Movement error calculation system, machine tool, calculation device, calibration method, and optical measurement device

Abstract

To provide a movement error calculation system capable of appropriately calculating a movement error.SOLUTION: This movement error calculation system calculates a movement error occurring in at least one of a mounting device on which a workpiece is mounted and a machining head equipped with a main spindle to which a tool is fitted. The movement error calculation system comprises: a reference member on which the mounting device is mounted; an object optical system that emits first light toward the reference member; a detector that receives second light advancing along an optical path of the first light among lights from the reference member, which are generated as a result of irradiation with the first light, via the object optical system; an optical detector fitted to the main spindle replacing the tool; and a calculation unit that calculates the movement error on the basis of the detection result of the optical detector.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to the technical fields of a movement error calculation system and calculation device capable of calculating a movement error that occurs in the movement of at least one of a mounting device and a head, a machine tool equipped with the movement error calculation system, and an optical measurement device capable of measuring an object. [Background technology]

[0002] Patent Document 1 describes a machine tool that calculates a movement error that occurs in the translational and rotational movements of first and second mechanical parts. In such a machine tool, a technical challenge is to appropriately calculate the movement error. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] U.S. Patent Publication No. 2018 / 0174317 Summary of the Invention

[0004] According to a first aspect, there is provided a movement error calculation system for calculating a movement error that occurs in the movement of at least one of a mounting device on which a workpiece is placed and a machining head of a machine tool that processes the workpiece with a tool detachably attached to the spindle of the machining head while moving at least one of the mounting device and the machining head, the movement error calculation system comprising: a reference member different from the workpiece placed on the mounting device; an objective optical system that irradiates a first light toward the reference member; and a detector that receives, via the objective optical system, a second light that travels along the optical path of the first light from the reference member generated by the irradiation of the first light, and also comprising an optical detection device attached to the spindle in place of the tool; and a calculation unit that calculates the movement error based on the detection result by the optical detection device.

[0005] According to a second aspect, there is provided a machine tool comprising the movement error calculation system provided by the first aspect, the machining head, the placement device, and a drive device for moving at least one of the machining head and the placement device.

[0006] According to a third aspect, there is provided a calculation device that calculates a movement error that occurs in the movement of at least one of a mounting device on which a workpiece can be placed and a head on which a processing unit for processing the workpiece can be attached, the calculation device comprising: an objective optical system that irradiates a first light toward a reference member placed on the mounting device; and a detector that receives, via the objective optical system, a second light from the reference member generated by the irradiation of the first light, and an arithmetic unit that calculates the movement error based on the detection result by a light detection device attached to the head.

[0007] According to a fourth aspect, there is provided a calibration method including irradiating a first light from an objective optical system of an optical detection device attached to a head to which a processing unit for processing a workpiece can be attached, toward a reference member placed on a placement device; receiving a second light from the reference member generated by the irradiation of the first light via the objective optical system using a detector of the optical detection device; and calibrating information used to control the movement of at least one of the placement device and the head based on the detection result by the optical detection device.

[0008] According to a fifth aspect, there is provided an optical measurement device comprising: an objective optical system; a measurement unit that irradiates a first light toward an object via the objective optical system and receives a second light from the object generated by the irradiation of the first light via the objective optical system; a focusing optical system that is provided in the optical path between the objective optical system and the measurement unit and forms a focusing point of the first light at a focal position of the objective optical system on the measurement unit side; and a calculation unit that measures at least a portion of the object based on the light reception result by the measurement unit.

[0009] According to a sixth aspect, there is provided a calculation device for calculating a movement error that occurs in the movement of at least one of a mounting device on which a workpiece can be placed and a head on which a processing unit for processing the workpiece can be attached, the calculation device comprising an objective optical system that irradiates a first light toward a reference member placed on the mounting device, receives a second light from the reference member generated by the irradiation of the first light via the objective optical system, and comprises an arithmetic unit that calculates the movement error based on the detection result by a light detection device attached to the head.

[0010] The functions and other advantages of the present invention will become apparent from the following detailed description of the preferred embodiments. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a perspective view showing the appearance of a machine tool according to this embodiment. [Figure 2] FIG. 2 is a system configuration diagram showing the system configuration of the machine tool in this embodiment. [Figure 3] FIG. 3 is a cross-sectional view showing the structure of the machining head in this embodiment. [Figure 4] FIG. 4 is a cross-sectional view showing the structure of the machining head in this embodiment. [Figure 5] FIG. 5 is a cross-sectional view showing a processing head to which a measuring device (particularly, a measuring head) according to this embodiment is attached. [Figure 6] FIG. 6 is a cross-sectional view showing a processing head to which a measuring device (particularly, a measuring head) according to this embodiment is attached. [Figure 7] FIG. 7 is a cross-sectional view showing an optical system that irradiates a measurement object with measurement light and detects return light from the measurement object. [Figure 8] FIG. 8 is a cross-sectional view showing the structure of an optical system provided in the measurement head of this embodiment. [Figure 9] FIG. 9 is a table showing the movement error. [Figure 10] FIG. 10 is a cross-sectional view showing a reference member and a measurement head that measures the reference member. [Figure 11] 11(a) and 11(b) are cross-sectional views showing a reference member and a measurement head that measures the reference member. [Figure 12] 12(a) and 12(b) are cross-sectional views showing a reference member and a measurement head that measures the reference member. [Figure 13] FIG. 13 is a cross-sectional view showing a reference member and a measurement head that measures the reference member. [Figure 14] FIG. 14 is a cross-sectional view showing a reference member and a measurement head that measures the reference member. [Figure 15] FIG. 15 shows the first reference member. [Figure 16] FIG. 16 schematically shows a method for calculating a movement error using the first reference member. [Figure 17] FIG. 17 schematically shows a method for calculating a movement error using the first reference member. [Figure 18] FIG. 18 shows the measurement results of the grating pattern before the processing head moves and the measurement results of the grating pattern after the processing head moves. [Figure 19] FIG. 19 shows the measurement results of the grating pattern before the processing head moves and the measurement results of the grating pattern after the processing head moves. [Figure 20] FIG. 20 shows the boundaries of the reference region. [Figure 21] FIG. 21 shows the boundaries of the reference region. [Figure 22] FIG. 22 shows the second reference member. [Figure 23] FIG. 23 schematically shows a method for calculating a movement error using a second reference member. [Figure 24] FIG. 24 schematically shows a method for calculating a movement error using a second reference member. [Figure 25] FIG. 25 shows a third reference member. [Figure 26] FIG. 26 is a cross-sectional view showing the structure of a first reflector provided on the third reference member. [Figure 27]FIG. 27 is a cross-sectional view showing the structure of a second reflector provided on the third reference member. [Figure 28] FIG. 28 is a cross-sectional view showing another structure of the second reflector provided in the third reference member. [Figure 29] FIG. 29 is a cross-sectional view showing another structure of the second reflector provided in the third reference member. [Figure 30] FIG. 30 is a cross-sectional view showing another structure of the second reflector provided in the third reference member. [Figure 31] FIG. 31 is a cross-sectional view showing the structure of the optical system of the measurement head in the first modified example. [Figure 32] FIG. 32 is a cross-sectional view showing the structure of the optical system of the measurement head in the second modified example. [Figure 33] FIG. 33 is a cross-sectional view showing the structure of the optical system of the measurement head in the second modified example. [Figure 34] FIG. 34 shows a measurement head that irradiates a reference member with measurement light. [Figure 35] Each of FIGS. 35(a) and 35(b) schematically shows the result of merging the calculation result of the position of the first portion of the reference member and the calculation result of the position of the second portion of the reference member. [Figure 36] Each of Figures 36(a) to 36(e) schematically shows the result of merging the calculation result of the position of the first part of the reference member and the calculation result of the position of the second part of the reference member when a movement error occurs. [Figure 37] FIG. 37 is a cross-sectional view showing the structure of a measurement head in the fourth modified example. [Figure 38] FIG. 38 is a cross-sectional view showing the structure of an optical system provided in a measurement head in the fourth modified example. [Figure 39] FIG. 39 is a system configuration diagram showing the system configuration of a machine tool in the fifth modified example. [Figure 40] FIG. 40 is a system configuration diagram showing the system configuration of a machine tool in the sixth modified example. [Figure 41] FIG. 41 is a side view showing the configuration of a head drive system of a machine tool in the seventh modified example. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of a movement error calculation system, a machine tool, a calculation device, a calculation method, a calculation system, a position calculation device, a position calculation method, a position calculation system, an optical measurement device, a calibration method, an optical processing machine, a measuring machine, a computer program, and a recording medium will be described with reference to the drawings. Hereinafter, embodiments of a movement error calculation system, a machine tool, a calculation device, a calculation method, a calculation system, a position calculation device, a position calculation method, a position calculation system, an optical measurement device, a calibration method, an optical processing machine, a measuring machine, a computer program, and a recording medium will be described using a machine tool 1 that can process a workpiece W, which is an example of an object.

[0013] In the following explanation, the positional relationships of the various components that make up the machine tool 1 will be described using an XYZ Cartesian coordinate system defined by mutually orthogonal X, Y, and Z axes. For convenience of explanation, the following explanation will be given using an example in which the X-axis direction and the Y-axis direction are horizontal (i.e., predetermined directions within a horizontal plane) and the Z-axis direction is vertical (i.e., a direction perpendicular to the horizontal plane, essentially an up-and-down direction). Furthermore, the rotation directions around the X-axis, Y-axis, and Z-axis (in other words, tilt directions) may be referred to as the θX direction, the θY direction, and the θZ direction, respectively.

[0014] (1) Structure of machine tool 1 First, the configuration of the machine tool 1 in this embodiment will be described.

[0015] (1-1) Overall structure of machine tool 1 First, the structure of a machine tool 1 in this embodiment will be described with reference to Figures 1 and 2. Figure 1 is a perspective view showing the appearance of the machine tool 1 in this embodiment. Figure 2 is a system configuration diagram showing an example of the system configuration of the machine tool 1 in this embodiment.

[0016] 1 and 2, the machine tool 1 includes a machining head 2, a head drive system 3, a stage device 4, a measuring device 5, a tool changer 6, a control device 7, and an output device 8. However, the machine tool 1 does not necessarily have to include at least one of the tool changer 6 and the output device 8. To make the drawings easier to understand, the measuring device 5, tool changer 6, control device 7, and output device 8 are omitted from FIG. 1.

[0017] The machining head 2 is a machining device for machining the workpiece W. The machining head 2 includes a main spindle 21 and a head housing 22. The machining head 2 will be described below with reference to Figs. 3 and 4 in addition to Figs. 1 and 2. Figs. 3 and 4 are each a cross-sectional view showing the structure of the machining head 2. The machining head 2 can also be simply referred to as a head.

[0018] As shown in Fig. 1 and Figs. 3 and 4, the main shaft 21 is a member that can rotate around a rotation axis RX. In this case, the main shaft 21 may be, for example, a member that extends along the rotation axis RX (i.e., a member having an elongated shape). In the example shown in Fig. 1, the rotation axis RX of the main shaft 21 is parallel to the Z axis. However, the main shaft 21 may also rotate around a rotation axis RX that intersects the Z axis (for example, a rotation axis RX that is perpendicular to the Z axis or inclined with respect to the Z axis).

[0019] As shown in Fig. 4, a tool 23 for machining the workpiece W (i.e., a machining tool) can be attached to the spindle 21. Specifically, as shown in Figs. 3 and 4, the spindle 21 is provided with an attachment portion 211 for attaching the tool 23. The tool 23 is attached to the spindle 21 via the attachment portion 211. The tool 23 attached to the attachment portion 211 can be removed from the attachment portion 211. In other words, the tool 23 is attached to the spindle 21 in a detachable manner.

[0020] In this embodiment, the state in which "a first object is attached to a second object" may include at least one of a state in which "the first object is directly attached to the second object (i.e., the first object is attached to the second object so that the first object and the second object are in contact)" and a state in which "the first object is indirectly attached to the second object (i.e., the first object is attached to the second object without the first object and the second object being in contact)." The state in which "the first object is indirectly attached to the second object" may also include a state in which "the first object is attached to the second object via a third object different from the first and second objects."

[0021] 3 and 4, the spindle 21 is provided with a mounting portion 211 at the tip of the spindle 21 (specifically, the tip on the workpiece W side), which has a hole 212 (e.g., a tapered hole) formed therein, into which the tool 23 is fitted (or inserted). In this case, a shank 231 of the tool 23, which has a shape complementary to the hole 212, is fitted (or inserted) into the hole 212 of the mounting portion 211, thereby mounting the tool 23 to the spindle 21. The mounting portion 211 may hold the tool 23 mounted thereon. In this case, the mounting portion 211 may include at least one of a mechanical chuck, an electrostatic chuck, a vacuum chuck, or the like, in order to hold the tool 23.

[0022] When the spindle 21 rotates with the tool 23 attached to it, the tool 23 also rotates around the rotation axis RX. As a result, the rotating tool 23 comes into contact with the workpiece W, machining the workpiece W. In this way, the machine tool 1 (particularly, the machining head 2) can machine the workpiece W using the spindle 21 and the tool 23. In this case, the spindle 21 (and further the tool 23) may be referred to as a processing section for processing (here, machining) the workpiece W.

[0023] Head housing 22 is a housing that houses spindle 21. Head housing 22 may house spindle 21 in a housing space formed inside head housing 22. Spindle 21 housed in head housing 22 may be supported by head housing 22 via a bearing member (for example, a bearing) not shown.

[0024] 1 and 2 again, the head drive system 3 moves the machining head 2. The head drive system 3 may also be referred to as a drive device. The head drive system 3 may, for example, move the machining head 2 along at least one of the X-axis direction, the Y-axis direction, and the Z-axis direction. The head drive system 3 may, for example, move the machining head 2 along at least one of the θX direction, the θY direction, and the θZ direction in addition to or instead of at least one of the X-axis direction, the Y-axis direction, and the Z-axis direction. That is, in addition to or instead of moving the machining head 2 along at least one of the X-axis direction, the Y-axis direction, and the Z-axis direction, the head drive system 3 may rotate the machining head 2 around at least one of the rotational axes along the X-axis direction, the Y-axis direction, and the Z-axis direction. The movement along at least one of the θX direction (the direction around the rotational axis along the X-axis direction), the θY direction (the direction around the rotational axis along the Y-axis direction), and the θZ direction (the direction around the rotational axis along the Z-axis direction) may also be referred to as a rotational movement. In the following description, the rotation axis along the X-axis direction, the rotation axis along the Y-axis direction, and the rotation axis along the Z-axis direction will be referred to as the A-axis, the B-axis, and the C-axis, respectively. Note that the operation of moving the machining head 2 along the rotation direction around at least one of the A-axis, B-axis, and C-axis may be considered equivalent to the operation of changing the attitude of the machining head 2.

[0025] 1, the head drive system 3 moves the machining head 2 along both the X-axis and the Z-axis. In this case, the head drive system 3 may include, for example, a column 31, which is a wall-like member extending upward along the Z-axis from a bed 40, which is the base of a stage device 4 described later; an X-guide member 32 attached to (or formed on) the column 31 and extending along the X-axis; an X-block member 33 attached to (or movable along) the X-guide member 32; a servo motor 34 that generates a driving force for moving the X-block member 33; a Z-guide member 35 attached to (or formed on) the X-block member 33 and extending along the Z-axis; a Z-block member (not shown in FIG. 1) attached to the Z-guide member 35 and movable along the Z-guide member 35; and a servo motor 36 that generates a driving force for moving the Z-block member. The machining head 2 (particularly, the head housing 22) may be attached to the Z-block member. As a result, the machining head 2 moves in the X-axis direction in accordance with the movement of the X-block member 33, and moves in the Z-axis direction in accordance with the movement of the Z-block member.

[0026] When the head drive system 3 moves the machining head 2, the relative positional relationship between the machining head 2 and the stage 41 (described later) (and further, the workpiece W placed on the stage 41) changes. As a result, the relative positional relationship between the machining position where the machining head 2 performs machining and the workpiece W changes. In other words, the machining position moves relative to the workpiece W. The machine tool 1 may machine the workpiece W while moving the machining head 2. Specifically, the machine tool 1 may machine the desired position of the workpiece W while setting the machining position at the desired position of the workpiece W by moving the machining head 2. However, if the machining position can be set at the desired position of the workpiece W by moving the stage 41 (described later), the machine tool 1 may machine the workpiece W without moving the machining head 2.

[0027] The stage device 4 includes a bed 40, a stage 41, and a stage drive system 42. The stage 41 and the stage drive system 42 are supported by the bed 40.

[0028] The workpiece W is placed on the stage 41. For this reason, the stage 41 may be referred to as a placement device. The stage 41 is capable of supporting the workpiece W placed on the stage 41. The stage 41 may be capable of holding the workpiece W placed on the stage 41. In this case, the stage 41 may be equipped with at least one of a mechanical chuck, an electrostatic chuck, a vacuum chuck, or the like to hold the workpiece W.

[0029] The stage 41 is disposed at a position where it can face the machining head 2 (particularly, the spindle 21). In the example shown in Fig. 1, the stage 41 is disposed below the machining head 2 (particularly, the spindle 21). However, the stage 41 may be disposed at a position different from the position below the machining head 2 (particularly, the spindle 21).

[0030] The stage drive system 42 moves the stage 41. The stage drive system 42 may also be referred to as a drive device. The stage drive system 42 may move the stage 41, for example, along at least one of the X-axis direction, the Y-axis direction, and the Z-axis direction. The stage drive system 42 may move the stage 41, for example, along at least one of the θX direction, the θY direction, and the θZ direction in addition to or instead of at least one of the X-axis direction, the Y-axis direction, and the Z-axis direction. That is, in addition to or instead of moving the stage 41 along at least one of the X-axis direction, the Y-axis direction, and the Z-axis direction, the stage drive system 42 may rotate the stage 41 around at least one of a rotation axis along the X-axis direction (i.e., the A-axis), a rotation axis along the Y-axis direction (i.e., the B-axis), and a rotation axis along the Z-axis direction (i.e., the C-axis). The operation of moving the stage 41 along a rotation direction around at least one of the A-axis, B-axis, and C-axis may be considered equivalent to an operation of changing the attitude of the stage 41.

[0031] 1 , stage drive system 42 moves stage 41 along the Y-axis direction and rotates stage 41 around each of the rotation axes of the A-axis and C-axis. In this case, stage drive system 42 may include, for example, a Y guide member 421 attached to (or formed on) bed 40 and extending along the Y-axis direction, a trunnion (Y block member) 422 attached to Y guide member 421 and movable along Y guide member 421, a servo motor 423 that generates a driving force for moving trunnion 422, a cradle 424 attached to trunnion 422 and rotatable about the A-axis relative to trunnion 422, and a servo motor (not shown) that generates a driving force for rotating cradle 424. Stage 41 may be attached to cradle 424 so as to be rotatable about the C-axis relative to cradle 424 using the driving force generated by the servo motor (not shown). As a result, the stage 41 moves in the Y-axis direction in accordance with the movement of the trunnion 422, rotates around the A-axis in accordance with the rotation of the cradle 424, and rotates around the C-axis.

[0032] When the stage drive system 42 moves the stage 41, the relative positional relationship between the machining head 2 and the stage 41 (and further, the workpiece W placed on the stage 41) changes. As a result, the relative positional relationship between the machining position where the machining head 2 performs machining and the workpiece W changes. In other words, the machining position moves relative to the workpiece W. The machine tool 1 may machine the workpiece W while moving the stage 41. Specifically, the machine tool 1 may machine the desired position of the workpiece W while setting the machining position at the desired position of the workpiece W by moving the stage 41. However, if the machining position can be set at the desired position of the workpiece W by moving the above-mentioned machining head 2, the machine tool 1 may machine the workpiece W without moving the stage 41.

[0033] The measurement device 5 is capable of measuring a measurement object. For example, the measurement device 5 may be capable of measuring the characteristics of the measurement object. The characteristics of the measurement object may include, for example, at least one of the position of the measurement object, the shape of the measurement object, the distance between the measurement device 5 and the measurement object, the reflectance of the measurement object, the transmittance of the measurement object, the temperature of the measurement object, and the surface roughness of the measurement object.

[0034] In the following description, an example will be described in which the measurement device 5 measures at least the position of the measurement object. The position of the measurement object may include the position of the surface of the measurement object. The position of the surface of the measurement object may include the position of at least a portion of the surface of the measurement object. The position of the measurement object may also mean the position of the measurement object relative to the measurement device 5 (i.e., the relative position). In other words, the position of the measurement object may mean the position of the measurement object in a measurement coordinate system based on the measurement device 5. The position of the measurement object relative to the measurement device 5 may include the position of the measurement object along a first direction relative to the measurement device 5. The position of the measurement object along the first direction relative to the measurement device 5 may be considered equivalent to the distance between the measurement device 5 and the measurement object along the first direction. The position of the measurement object relative to the measurement device 5 may include the positions of the measurement object along both the first direction and a second direction intersecting the first direction relative to the measurement device 5. The position of the measurement object relative to the measurement device 5 along each of the first and second directions may be considered equivalent to the distance between the measurement device 5 and the measurement object along the first direction and the distance between the measurement device 5 and the measurement object along the second direction. The position of the measurement object relative to the measurement device 5 may include the position of the measurement object relative to the measurement device 5 along each of the first direction, the second direction intersecting the first direction, and the third direction intersecting the first and second directions. The position of the measurement object relative to the measurement device 5 along each of the first to third directions may be considered equivalent to the distance between the measurement device 5 and the measurement object along the first direction, the distance between the measurement device 5 and the measurement object along the second direction, and the distance between the measurement device 5 and the measurement object along the third direction.

[0035] The position of each portion of the surface of the measurement object changes depending on the shape of the surface of the measurement object. Therefore, the operation of measuring the position of the measurement object may be considered equivalent to the operation of measuring the shape of the measurement object. The shape of the measurement object may include at least one of a one-dimensional shape, a two-dimensional shape, and a three-dimensional shape of the measurement object.

[0036] The measurement object may include, for example, a workpiece W to be machined by the machining head 2. The measurement object may include, for example, any object placed on the stage 41. The any object placed on the stage 41 may include, for example, the workpiece W. The any object placed on the stage 41 may include a reference member FM used in the movement error calculation operation described below. The measurement object may include, for example, the stage 41.

[0037] The measurement device 5 may be capable of measuring the measurement object without contact. The measurement device 5 may be capable of measuring the measurement object optically. The measurement device 5 may be capable of measuring the measurement object electrically. The measurement device 5 may be capable of measuring the measurement object magnetically. The measurement device 5 may be capable of measuring the measurement object thermally. The measurement device 5 may be capable of measuring the measurement object acoustically. The measurement device 5 may be capable of measuring the measurement object using a probe that physically contacts the measurement object.

[0038] In the following description, an example will be given in which the measurement device 5 is capable of optically measuring the measurement object. In this case, the measurement device 5 may be referred to as an optical measurement device. Specifically, in the following description, an example will be given in which the measurement device 5 measures the measurement object by irradiating the measurement object with measurement light ML (see FIG. 7 , etc., described later) and detecting (i.e., receiving) at least a portion of the light from the measurement object irradiated with the measurement light ML. The light from the measurement object irradiated with the measurement light ML is light from the measurement object that is generated by the irradiation of the measurement light ML. In the following description, the light that enters the measurement device 5 (i.e., is detected by the measurement device 5) of the light from the measurement object irradiated with the measurement light ML is referred to as "return light RL."

[0039] In this embodiment, in order to optically measure the measurement object, the measurement device 5 may include, for example, a measurement light source 51, a measurement head 52, and an output interface 53. The structure and operation of the measurement device 5 will be described in detail later, but will be briefly outlined here. The measurement light source 51 is capable of generating measurement light ML. The measurement head 52 is attached to the processing head 2. That is, the measurement head 52 is disposed on the processing head 2. The measurement head 52 attached to the processing head 2 may be fixed to the processing head 2. The measurement head 52 attached to the processing head 2 may be detachable from the processing head 2. For simplicity of illustration, the measurement head 52 attached to the processing head 2 is not shown in FIG. 1 . However, the measurement head 52 attached to the processing head 2 is illustrated in FIGS. 5 and 6 , etc., which will be used to later describe the structure and operation of the measurement device 5. The measurement device 5 irradiates the measurement light ML onto the measurement object using the measurement head 52. Furthermore, the measurement device 5 detects return light RL from the measurement object irradiated with the measurement light ML using the measurement head 52. For this reason, the measurement head 52 may be referred to as a light detection device. The output interface 53 can output the measurement results by the measurement device 5 (i.e., the detection results of the return light RL from the measurement object) to the control device 7.

[0040] The tool changer 6 is a device capable of changing the tool 23 attached to the spindle 21. For example, the tool changer 6 may retrieve one tool 23 to be attached to the spindle 21 from a tool magazine (not shown) that stores a plurality of tools 23, and attach the retrieved tool 23 to the spindle 21. In other words, the tool changer 6 may function as an attachment device capable of attaching the tool 23 to the spindle 21. The tool changer 6 may remove the tool 23 attached to the spindle 21 from the spindle 21 and store the removed tool 23 in a tool magazine (not shown). In other words, the tool changer 6 may function as a removal device capable of removing the tool 23 from the spindle 21. Note that an automatic tool changer (ATC) used in a machining center or the like may be used as the tool changer 6.

[0041] In this embodiment, as will be described in detail later, a measuring head 52 provided in the measuring device 5 may be attached to the spindle 21 in addition to the tool 23. In this case, the tool changer 6 may function as an attachment device capable of attaching the measuring head 52 to the spindle 21. That is, the tool changer 6 may remove the measuring head 52 from a tool magazine (not shown) that stores the measuring head 52 in addition to the tool 23 (or from a head magazine (not shown) that stores the measuring head 52 and is different from the tool magazine that stores the tool 23), and attach the removed measuring head 52 to the spindle 21. The tool changer 6 may also function as a removal device capable of removing the measuring head 52 from the spindle 21. That is, the tool changer 6 may remove the measuring head 52 attached to the spindle 21 from the spindle 21, and store the removed measuring head 52 in a tool magazine (not shown) or a head magazine (not shown).

[0042] The control device 7 controls the operation of the machine tool 1. For example, the control device 7 may control the operation of the machining head 2 provided in the machine tool 1 (e.g., rotation of the spindle 21). For example, the control device 7 may control the operation of the head drive system 3 provided in the machine tool 1 (e.g., movement of the machining head 2). For example, the control device 7 may control the operation of the stage drive system 42 provided in the machine tool 1 (e.g., movement of the stage 41). For example, the control device 7 may control the operation of the tool changer 6 provided in the machine tool 1 (i.e., replacement of the tool 23 attached to the spindle 21 and the measuring head 52).

[0043] The control device 7 may acquire the measurement results by the measuring device 5 from the output interface 53 of the measuring device 5, and may control the operation of the machine tool 1 based on the acquired measurement results. For example, the control device 7 may generate measurement data of the measurement object (e.g., data relating to at least one of the position and shape of the measurement object) based on the measurement results by the measuring device 5, and control the operation of the machine tool 1 based on the generated measurement data.

[0044] In this embodiment, the control device 7 performs a movement error calculation operation to calculate a movement error (in other words, a motion error) occurring in the movement of at least one of the machining head 2 and the stage 41, based on the measurement results from the measuring device 5. Specifically, the control device 7 performs the movement error calculation operation based on the measurement results of the reference member FM, which will be described later, by the measuring device 5. The control device 7 that performs the movement error calculation operation may also be referred to as a movement error calculation device or a calculation device. A system including the measuring device 5 and the control device 7 may also be referred to as a movement error calculation system or a calculation system. A system including the reference member FM, which will be described later, and the control device 7 may also be referred to as a movement error calculation system or a calculation system. A system including the reference member FM, the measuring device 5, and the control device 7 may also be referred to as a movement error calculation system or a calculation system. The movement error calculation operation will be described in detail later with reference to FIG. 9 and the like. Here, the reference member FM may be, for example, a member having known characteristics. As an example, the known characteristics of the reference member FM may include shape, dimensions, reflectance (reflectance distribution), and / or transmittance (transmittance distribution). The reference member FM may be a member having one or more feature points within the measurement range of the measurement device 5. Here, the presence of one or more feature points within the measurement range may refer to a state in which a feature point exists within a hypothetical region on the surface of the reference member FM corresponding to the measurement range. A feature point is, for example, a point whose position can be distinguished from other points and whose position can be identified, and whose characteristics may differ from the characteristics of other points. Examples of such characteristics may include the position or reflectance (transmittance) of the point. A feature point may be a vertex or corner of a region that can be distinguished from other regions, or may be the boundary of that region. Using a reference member FM having one or more feature points within the measurement range of the measurement device 5 has the advantage of reducing measurement errors.

[0045] The control device 7 may include, for example, an arithmetic device and a storage device. The arithmetic device may include, for example, at least one of a CPU (Central Processing Unit) and a GPU (Graphics Processing Unit). The storage device may include, for example, a memory. The control device 7 functions as a device that controls the operation of the machine tool 1 by the arithmetic device executing a computer program. This computer program is a computer program for causing the arithmetic device to perform (i.e., execute) the operations to be performed by the control device 7, which will be described later. In other words, this computer program is a computer program for causing the control device 7 to function so as to cause the machine tool 1 to perform the operations to be performed by the control device 7. The computer program executed by the arithmetic device may be recorded in a storage device (i.e., a recording medium) included in the control device 7, or may be recorded in any storage medium (e.g., a hard disk or semiconductor memory) built into or externally attachable to the control device 7. Alternatively, the arithmetic device may download the computer program to be executed from a device external to the control device 7 via a network interface.

[0046] The control device 7 does not have to be provided inside the machine tool 1. For example, the control device 7 may be provided outside the machine tool 1 as a server or the like. In this case, the control device 7 and the machine tool 1 may be connected via a wired and / or wireless network (or a data bus and / or a communication line). The wired network may be a network using a serial bus interface, such as at least one of IEEE1394, RS-232x, RS-422, RS-423, RS-485, and USB. The wired network may be a network using a parallel bus interface. The wired network may be a network using an interface compliant with Ethernet (registered trademark), such as at least one of 10BASE-T, 100BASE-TX, and 1000BASE-T. The wireless network may be a network using radio waves. An example of a network using radio waves is a network compliant with IEEE802.1x (for example, at least one of wireless LAN and Bluetooth (registered trademark)). The wireless network may be an infrared network. A network using optical communication may be used as the wireless network. In this case, the control device 7 and the machine tool 1 may be configured to be able to send and receive various information via the network. The control device 7 may also be able to send information such as commands and control parameters to the machine tool 1 via the network. The machine tool 1 may include a receiving device that receives information such as commands and control parameters from the control device 7 via the network. The machine tool 1 may also include a transmitting device that transmits information such as commands and control parameters to the control device 7 via the network (i.e., an output device that outputs information to the control device 7). Alternatively, a first control device that performs part of the processing performed by the control device 7 may be provided inside the machine tool 1, while a second control device that performs another part of the processing performed by the control device 7 may be provided outside the machine tool 1.

[0047] A computational model that can be constructed by machine learning may be implemented in the control device 7 by the computation device executing a computer program. An example of a computational model that can be constructed by machine learning is a computational model including a neural network (so-called artificial intelligence (AI)). In this case, learning of the computational model may include learning of parameters of the neural network (for example, at least one of weights and biases). The control device 7 may control the operation of the machine tool 1 using the computational model. That is, the operation of controlling the operation of the machine tool 1 may include the operation of controlling the operation of the machine tool 1 using the computational model. Note that the control device 7 may be implemented with a computational model that has been constructed by offline machine learning using training data. Furthermore, the computational model implemented in the control device 7 may be updated by online machine learning on the control device 7. Alternatively, the control device 7 may control the operation of the machine tool 1 using a computational model implemented in a device external to the control device 7 (that is, a device provided outside the machine tool 1) in addition to or instead of the computational model implemented in the control device 7.

[0048] The recording medium for recording the computer program executed by the control device 7 may be at least one of a CD-ROM, CD-R, CD-RW, flexible disk, optical disk such as MO, DVD-ROM, DVD-RAM, DVD-R, DVD+R, DVD-RW, DVD+RW, and Blu-ray®, magnetic medium such as magnetic tape, magneto-optical disk, semiconductor memory such as USB memory, and any other medium capable of storing a program. The recording medium may include a device capable of recording a computer program (e.g., a general-purpose device or a dedicated device in which a computer program is implemented in an executable state in at least one of software and firmware). Furthermore, each process or function included in the computer program may be realized by logical processing blocks realized within the control device 7 when the control device 7 (i.e., a computer) executes the computer program, or by hardware such as a predetermined gate array (FPGA (Field Programmable Gate Array) or ASIC (Application Specific Integrated Circuit)) included in the control device 7, or may be realized in a form in which logical processing blocks and partial hardware modules that realize some of the hardware elements are mixed together.

[0049] Output device 8 is a device that outputs information to the outside of machine tool 1. For example, output device 8 may output information as an image. That is, output device 8 may include a display device (a so-called display) capable of displaying an image. For example, output device 8 may output information as sound. That is, output device 8 may include an audio output device (a so-called speaker) capable of outputting sound. For example, output device 8 may output information on paper. That is, output device 8 may include a printing device (a so-called printer) capable of printing desired information on paper. For example, output device 8 may output information as data to a recording medium that can be externally attached to machine tool 1. For example, output device 8 may output (i.e., transmit) information as data via a communication line. That is, output device 8 may function as a communication device.

[0050] (1-2) Configuration of the measurement device 5 (measurement head 52) Next, the structure of the measuring device 5 will be described in more detail with reference to Fig. 5. Fig. 5 is a cross-sectional view showing the processing head 2 to which the measuring device 5 (particularly the measuring head 52) is attached.

[0051] As shown in FIG. 5, the measuring head 52 is attached to the machining head 2. Specifically, the measuring head 52 includes a head housing 521, and the head housing 521 is attached to the machining head 2. In the example shown in FIG. 5, the measuring head 52 is attached to the spindle 21 of the machining head 2. That is, the measuring head 52 is attached to the spindle 21 instead of the tool 23. Specifically, the head housing 521 is attached to an attachment portion 211 that the spindle 21 includes. In the example shown in FIG. 5, the spindle 21 includes an attachment portion 211 in which a hole 212 is formed. Therefore, the shank 520, which corresponds to a protruding portion of the head housing 521 and has a shape complementary to the hole 212, is fitted (or inserted) into the hole 212 of the attachment portion 211, thereby attaching the head housing 521 to the spindle 21. The attachment portion 211 may hold the head housing 521. In this case, the attachment portion 211 may include at least one of a mechanical chuck, an electrostatic chuck, a vacuum chuck, and the like to hold the head housing 521.

[0052] Head housing 521 (i.e., measuring head 52) attached to mounting portion 211 is detachable from mounting portion 211. That is, head housing 521 (i.e., measuring head 52) is detachably attached to spindle 21. For example, when measuring head 52 is attached to spindle 21, tool 23 is detached from spindle 21. On the other hand, when tool 23 is attached to spindle 21, measuring head 52 is detached from spindle 21. As described above, attachment and detachment of head housing 521 and attachment and detachment of tool 23 are performed by tool changer 6. However, an operator of machine tool 1 may manually perform at least one of attachment and detachment of measuring head 52 to and from spindle 21 and attachment and detachment of tool 23 to and from spindle 21.

[0053] However, the measurement head 52 may be attached to a part of the machining head 2 that is different from the spindle 21. For example, as shown in FIG. 6, which is a cross-sectional view showing the machining head 2 to which the measuring device 5 (particularly the measurement head 52) is attached, the measurement head 52 may be attached to the head housing 22 of the machining head 2. The head housing 521 may be attached to the head housing 22 of the machining head 2. The head housing 521 may be attached to the machining head 2 at a position separated from the rotation axis RX of the spindle 21 along a direction intersecting the rotation axis RX. In the example shown in FIG. 6, the head housing 521 is attached to the side of the head housing 22.

[0054] When the measuring head 52 is attached to a part of the machining head 2 that is different from the spindle 21, the measuring head 52 does not have to be detachable from the machining head 2. In other words, the measuring head 52 does not have to be detachably attached to the machining head 2. The measuring head 52 may remain attached to the machining head 2 even during the machining period in which the machining head 2 uses the tool 23 to machine the workpiece W. However, even when the measuring head 52 is attached to a part of the machining head 2 that is different from the spindle 21, the measuring head 52 may be detachably attached to the machining head 2.

[0055] The measurement head 52 may be attached at a fixed position relative to the processing head 2. In other words, the measurement head 52 may be attached to the processing head 2 so that the positional relationship between the processing head 2 and the measurement head 52 is fixed (i.e., does not change). The measurement head 52 may be attached and fixed directly to the processing head 2. The measurement head 52 may be attached and fixed indirectly to the processing head 2. For example, the measurement head 52 may be fixed to a support member whose other end is directly fixed to the processing head 2. Both a state in which the measurement head 52 is directly fixed to the processing head 2 and a state in which the measurement head 52 is directly fixed to the processing head 2 correspond to a state in which the measurement head 52 is attached at a fixed position relative to the processing head 2. Note that when the measurement head 52 is attached to the processing head 2, the positional relationship between the processing head 2 and the measurement head 52 is usually fixed unless the measurement device 5 is equipped with a drive system for moving the measurement head 52 independently of the processing head 2. Furthermore, when the measurement head 52 is attached to the main shaft 21 of the processing head 2, since the main shaft 21 is rotatable around the rotation axis RX, the rotation of the main shaft 21 may be locked using a mechanical fixing mechanism or the like when the measurement head 21 is attached to the main shaft 21.

[0056] However, the measuring head 52 does not have to be attached at a position where its positional relationship with the machining head 2 is fixed. The positional relationship between the machining head 2 and the measuring head 52 may be variable. The measuring device 5 may be equipped with a drive system for moving the measuring head 52 independently of the machining head 2. For example, this drive system may be configured to move the machining head 2 and the measuring head 52 relative to each other along the rotation axis RX. In this case, the control device 7 may measure the amount of movement of the machining head 2 and the measuring head 52 along the rotation axis RX using an encoder or the like, and may measure the movement error along this movement axis in advance and use this previously measured movement error to correct for the movement error of the machine tool 1 when calculating the movement error. As described above, when the measuring head 52 is attached to the head housing 22 of the machining head 2, there is a possibility that the measuring head 52 will interfere with the machining of the workpiece W during the machining period in which the machining head 2 processes the workpiece W with the tool 23. Specifically, for example, if the measuring head 52 comes into contact with the workpiece W (or another object) before the tool 23 comes into contact with the workpiece W, the tool 23 will not be able to come into contact with the workpiece W, and as a result, the measuring head 52 will interfere with the machining of the workpiece W. Therefore, the positional relationship between the machining head 2 and the measuring head 52 during at least a portion of the measurement period in which the measuring device 5 measures the measurement object may be different from the positional relationship between the machining head 2 and the measuring head 52 during at least a portion of the machining period in which the machining head 2 machines the workpiece W. For example, during at least a portion of the machining period, the positional relationship between the machining head 2 and the measuring head 52 may be set to a first relationship in which the measuring head 52 does not interfere with the machining of the workpiece W, and during at least a portion of the measurement period, the positional relationship between the machining head 2 and the measuring head 52 may be set to a second relationship different from the first relationship (for example, a second relationship in which the measuring device 5 can measure the measurement object using the measuring head 52).

[0057] When the measurement head 52 is attached to the processing head 2, the measurement head 52 also moves as the processing head 2 moves. In other words, the measurement head 52 moves in the same way as the processing head 2. For this reason, the head drive system 3 that moves the processing head 2 may be considered to function as a head drive system for moving the measurement head 52. In this case, the movement of the measurement head 52 changes the relative positional relationship between the measurement position where the measurement head 52 performs measurement and the measurement object. In other words, the measurement position moves with respect to the measurement object. The machine tool 1 may measure the measurement object while moving the measurement head 52 by moving the processing head 2. Specifically, the machine tool 1 may measure the desired position of the measurement object while setting the measurement position at a desired position of the measurement object by moving the measurement head 52. However, if the measurement object is the stage 41 or an object placed on the stage 41, the relative positional relationship between the measurement position where the measurement head 52 performs measurement and the measurement object also changes with the movement of the stage 41. Therefore, if the measurement position can be set at the desired position of the object to be measured by moving the stage 41, the machine tool 1 may measure the object to be measured without moving the measurement head 52.

[0058] When measuring head 52 is attached to spindle 21, measuring head 52 may also rotate about rotation axis RX as spindle 21 rotates. In this case, control device 7 may obtain in advance a movement error that accompanies the rotational movement of spindle 21, and may use this previously measured movement error to perform correction when calculating the movement error of machine tool 1.

[0059] The measurement head 52 further includes an optical system 522. The optical system 522 is housed in an internal storage space of the head housing 521. Therefore, the optical system 522 is attached to the processing head 2 via the head housing 521. When the optical system 522 is housed in the head housing 521 in this manner, unwanted substances (e.g., cutting chips, cutting fluid, etc.) generated by processing the workpiece W are prevented from adhering to the optical system 522.

[0060] The measurement head 52 may include a measurement light source 51. For example, the measurement light source 51 may be housed in the internal space of the head housing 521. In this case, the measurement light source 51 may be considered to constitute a part of the optical system 522. The measurement light source 51 may not be attached to the processing head 2, or may be attached to a part of the processing head 2 that is different from the main shaft 21. When the measurement device 52 includes multiple measurement light sources 51 (for example, measurement light sources 51#1 and 51#2 described later), at least one of the multiple measurement light sources 51 may not be attached to the processing head 2, or may be attached to a part of the processing head 2 that is different from the main shaft 21.

[0061] The optical system 522 is used to irradiate the measurement light ML from the measurement light source 51 onto the measurement object. Furthermore, the optical system 522 is used to detect return light RL from the measurement object. Specifically, as shown in FIG. 7, which is a cross-sectional view showing the optical system 522 that irradiates the measurement light ML onto the measurement object and detects return light RL from the measurement object, the measurement light ML generated by the measurement light source 51 enters the optical system 522 from the measurement light source 51 via an optical transmission member (not shown), such as an optical fiber. The optical system 522 emits the measurement light ML that has entered the optical system 522 toward the measurement object. In other words, the optical system 522 irradiates the measurement light ML onto the measurement object.

[0062] When the measurement light ML is irradiated onto the measurement object, light resulting from the irradiation of the measurement light ML is emitted from the measurement object. The light resulting from the irradiation of the measurement light ML may include reflected light of the measurement light ML irradiated onto the measurement object. The light resulting from the irradiation of the measurement light ML may include scattered light of the measurement light ML irradiated onto the measurement object. The light resulting from the irradiation of the measurement light ML may include transmitted light of the measurement light ML irradiated onto the measurement object. The light resulting from the irradiation of the measurement light ML may include diffracted light of the measurement light ML irradiated onto the measurement object.

[0063] At least a portion of the light generated by the irradiation of the measurement light ML is incident on the optical system 522 as return light RL from the measurement object. Specifically, a light component of the light generated by the irradiation of the measurement light ML that travels along the optical path of the measurement light ML is incident on the optical system 522 as return light RL. In this case, the optical path of the measurement light ML that is emitted from the fθ lens 5228 and incident on the measurement object may be the same as the optical path of the return light RL that is emitted from the measurement object and incident on the fθ lens 5228. As an example, when the measurement light ML is perpendicularly incident on the measurement object, the return light RL may be light that is mainly composed of specularly reflected light of the measurement light ML. Of course, when the measurement light ML is perpendicularly incident on the measurement object, the return light RL may include light other than the specularly reflected light of the measurement light ML (for example, at least one of diffusely reflected light, scattered light, transmitted light, and diffracted light of the measurement light ML). As another example, when the measurement light ML is obliquely incident on the measurement object (in other words, non-perpendicularly incident), the return light RL may be light mainly composed of diffusely reflected light of the measurement light ML. Of course, when the measurement light ML is obliquely incident on the measurement object, the return light RL may include light other than the diffusely reflected light of the measurement light ML (for example, at least one of specularly reflected light, scattered light, transmitted light, and diffracted light of the measurement light ML).

[0064] Here, the structure of the optical system 522 that irradiates the measurement object with the measurement light ML and detects the return light RL will be described in more detail with reference to Fig. 8. Fig. 8 is a cross-sectional view showing the structure of the optical system 522.

[0065] As shown in FIG. 8, the optical system 522 includes a beam splitter 5221, a beam splitter 5222, a detector (measurement unit) 5223, a beam splitter 5224, a mirror 5225, a detector (measurement unit) 5226, a galvanometer mirror 5227, and an fθ lens 5228.

[0066] Incidentally, the detector (measurement unit) 5223 of the optical system 522 does not have to be housed in the head housing 521. In other words, the detector (measurement unit) 5223 does not have to be attached to the machining head 2, or may be attached to a part of the machining head 2 different from the spindle 21. Similarly, at least one of the measurement light source 51, the beam splitter 5221, the beam splitter 5222, the detector (measurement unit) 5223, the beam splitter 5224, the mirror 5225, and the detector (measurement unit) 5226 may be housed in a housing different from the head housing 521 attached to the spindle 21 of the machining head 2. In this case, the housing different from the head housing 521 does not have to be attached to the machining head 2, or may be attached to a part of the machining head 2 different from the spindle 21, or may be attached outside a housing that houses at least one of the machining head 2, the head drive system 3, the stage device 4, and the measurement device 5 of the machine tool 1.

[0067] The measurement light ML from the measurement light source 51 is incident on the beam splitter 5221. In this embodiment, two measurement light sources 51 (specifically, measurement light sources 51#1 and 51#2) generate two measurement light beams ML, respectively, and these two measurement light sources 51 are incident on the beam splitter 5221. For this reason, the measurement device 5 includes a measurement light source 51#1 and a measurement light source 51#2. The two measurement light sources 51 may each emit two measurement light beams ML that are phase-synchronized and coherent with each other. However, the measurement device 5 may also include a single measurement light source 51.

[0068] The two measurement light sources 51 have different oscillation frequencies. Therefore, the two measurement light sources 51 respectively emit two measurement light beams ML with different frequencies. When the measurement light source 51 generates pulsed light as the measurement light beam ML, the two measurement light beams ML respectively emit two measurement light beams ML with different pulse frequencies (for example, the number of pulsed light beams per unit time, which is the reciprocal of the emission period of the pulsed light). As an example, the measurement light source 51#1 may emit measurement light beams ML with a pulse frequency of 25 GHz, and the measurement light source 51#2 may emit measurement light beams ML with a pulse frequency of 25 GHz+α (for example, +100 kHz). In the following description, the measurement light beams ML generated by the measurement light source 51#1 will be referred to as “measurement light beams ML#1,” and the measurement light beams ML generated by the measurement light source 51#2 will be referred to as “measurement light beams ML#2.” However, the two measurement light sources 51 may have the same oscillation frequency.

[0069] The measurement light source 51 includes an optical frequency comb light source. The optical frequency comb light source is a light source that can generate light containing frequency components that are evenly spaced on the frequency axis (hereinafter referred to as an "optical frequency comb") as pulsed light. In this case, the measurement light source 51 emits pulsed light containing frequency components that are evenly spaced on the frequency axis as measurement light ML. However, the measurement light source 51 may include a light source other than the optical frequency comb light source.

[0070] The two measurement beams ML#1 and ML#2 incident on the beam splitter 5221 are emitted toward the beam splitter 5222. That is, the beam splitter 5221 emits the measurement beams ML2#1 and ML#2 incident on the beam splitter 5221 from different directions in the same direction (that is, the direction in which the beam splitter 5222 is disposed).

[0071] Beam splitter 5222 emits measurement light ML#1-1, which is a part of measurement light ML#1 incident on beam splitter 5222, towards detector 5223. Beam splitter 5222 emits measurement light ML#1-2, which is another part of measurement light ML#1 incident on beam splitter 5222, towards beam splitter 5224. Beam splitter 5222 emits measurement light ML#2-1, which is a part of measurement light ML2#2 incident on beam splitter 5222, towards detector 5223. Beam splitter 5222 emits measurement light ML#2-2, which is another part of measurement light ML#2 incident on beam splitter 5222, towards beam splitter 5224.

[0072] The measurement beams ML#1-1 and ML#2-1 emitted from the beam splitter 5222 are incident on the detector 5223. The detector 5223 receives (i.e., detects) the measurement beams ML#1-1 and ML#2-1. In particular, the detector 5223 receives interference light generated by the interference between the measurement beams ML#1-1 and ML#2-1. Note that the operation of receiving interference light generated by the interference between the measurement beams ML#1-1 and ML#2-1 may be considered equivalent to the operation of receiving the measurement beams ML#1-1 and ML#2-1. The detection result by the detector 5223 (i.e., the reception result of the interference light) is output to the control device 7 via the output interface 53 as part of the measurement result of the measurement device 5.

[0073] Measurement beams ML#1-2 and ML#2-2 emitted from beam splitter 5222 are incident on beam splitter 5224. Beam splitter 5224 emits at least a portion of measurement beam ML#1-2 incident on beam splitter 5224 toward mirror 5225. Beam splitter 5224 emits at least a portion of measurement beam ML#2-2 incident on beam splitter 5224 toward galvanometer mirror 5227.

[0074] The measurement light ML#1-2 emitted from the beam splitter 5224 is incident on the mirror 5225. The measurement light ML#1-2 incident on the mirror 5225 is reflected by the reflecting surface of the mirror 5225 (the reflecting surface may also be referred to as a reference surface). Specifically, the mirror 5225 reflects the measurement light ML#1-2 incident on the mirror 5225 toward the beam splitter 5224. That is, the mirror 5225 emits the measurement light ML#1-2 incident on the mirror 5225 as measurement light ML#1-3, which is its reflected light, toward the beam splitter 5224. In this case, the measurement light ML#1-3 may also be referred to as a reference light. The measurement light ML#1-3 emitted from the mirror 5225 is incident on the beam splitter 5224. Beam splitter 5224 emits measurement beams ML#1-3 incident on beam splitter 5224 toward beam splitter 5222. Measurement beams ML#1-3 emitted from beam splitter 5224 are incident on beam splitter 5222. Beam splitter 5222 emits measurement beams ML#1-3 incident on beam splitter 5222 toward detector 5226.

[0075] On the other hand, measurement light ML#2-2 emitted from beam splitter 5224 toward galvanometer mirror 5227 is incident on galvanometer mirror 5227. Galvanometer mirror 5227 can change the traveling direction of measurement light ML#2-2 emitted from galvanometer mirror 5227 toward fθ lens 5228 so as to change the irradiation position of measurement light ML (measurement light ML#2-2 in this case) on the measurement object. For this reason, galvanometer mirror 5227 may be referred to as a traveling direction changing member. Galvanometer mirror 5227 may include an X-scanning mirror 52271 and a Y-scanning mirror 52272. X-scanning mirror 52271 and Y-scanning mirror 52272 are each a tilt-angle variable mirror that can change the angle with respect to the optical path of measurement light ML#2-2 incident on galvanometer mirror 5227. The X-scanning mirror 52271 changes the traveling direction of the measurement light ML#2-2 so that the irradiation position of the measurement light ML#2-2 on the measurement object changes along the X-axis direction. The Y-scanning mirror 52272 changes the traveling direction of the measurement light ML#2-2 so that the irradiation position of the measurement light ML#2-2 on the measurement object changes along the Y-axis direction.

[0076] Because the galvanometer mirror 5227 can change the irradiation position of the measurement light ML#2-2 on the measurement object in this way, the measurement device 5 can sequentially irradiate multiple parts of the measurement object with the measurement light ML#2-2. As a result, the measurement device 5 can measure multiple parts of the measurement object relatively quickly. In other words, the measurement device 5 can measure multiple points on the measurement object.

[0077] The measurement light ML#2-2 emitted from the galvanometer mirror 5227 is incident on the fθ lens 5228. The fθ lens 5228 can function as an objective optical system that irradiates the measurement light ML#2-2 onto the measurement object. The fθ lens 5228 may focus the measurement light ML#2-2 on the measurement object. That is, the fθ lens 5228 may irradiate the measurement light ML#2-2, which is converging light, onto the measurement object. In this case, the fθ lens 5228 may typically have a finite focal length. When the measurement light ML#2-2, which is converging light, is irradiated onto the measurement object, there is an advantage that the measurement accuracy of the measurement device 5 is relatively high because the diameter of the spot formed by the measurement light ML#2-2 on the surface of the measurement object is relatively small. However, as will be described in detail later in a modified example, the measurement head 52 may irradiate the measurement object with measurement light ML#2-2, which is parallel light (that is, collimated light).

[0078] The fθ lens 5228 may be a telecentric optical system on the measurement object side. In this case, even if the traveling direction of the measurement light ML#2-2 emitted from the galvanometer mirror 5227 changes, the traveling direction of the measurement light ML#2-2 emitted from the fθ lens 5228 remains parallel to the optical axis AX of the fθ lens 5228.

[0079] When the measurement head 52 is attached to the main shaft 21 of the processing head 2, the optical axis AX of the fθ lens 5228 may be coaxial with the rotation axis RX of the main shaft 21 (see FIG. 5 described above). In other words, the direction of the optical axis AX of the fθ lens 5228 may be a direction extending along the rotation axis RX. The optical axis AX of the fθ lens 5228 may coincide with the rotation axis RX. In this case, the fθ lens 5228 may emit the measurement light ML#2-2 so that the traveling direction of the measurement light ML#2-2 emitted from the fθ lens 5228 is a direction extending along the rotation axis RX. Note that, because the measurement light ML#2-2 emitted from the fθ lens 5228 becomes the measurement light ML#2-2 emitted from the optical system 522, the optical axis AX of the fθ lens 5228 may be considered to be the optical axis of the optical system 522 on the measurement object side (that is, a virtual light ray representing the light beam of the measurement light ML#2-2 emitted from the optical system 522 toward the measurement object). However, even when the measurement head 52 is attached to the main shaft 21 of the processing head 2, the optical axis AX of the fθ lens 5228 does not have to be coaxial with the rotation axis RX. For example, the optical axis AX of the fθ lens 5228 may be parallel to the rotation axis RX. The optical axis AX of the fθ lens 5228 may intersect with the rotation axis RX. The optical axis AX of the fθ lens 5228 may be in a twisted relationship with respect to the rotation axis RX. Even when the measurement head 52 is attached to a part of the processing head 2 that is different from the main shaft 21, the optical axis AX of the fθ lens 5228 does not have to be coaxial with the rotation axis RX (see FIG. 6 described above).

[0080] In order for the measurement head 52 to irradiate the workpiece W with the measurement light ML#2-2, the measurement head 52 is only required to include at least an fθ lens 5228. In this case, the measurement light ML#2-2 may be incident on the measurement head 52 via an optical system arranged outside the measurement head 52 (for example, an optical system that differs from the optical system 522 in that it does not include the fθ lens 5228). The measurement head 52 may irradiate the measurement light ML#2-2 incident on the measurement head 52 onto the workpiece W via the fθ lens 5228.

[0081] When the measurement light ML is irradiated onto the measurement object (workpiece W in the example shown in FIG. 6), return light RL, which is at least a part of the light generated by the irradiation of the measurement object with the measurement light ML, is emitted from the measurement object. The return light RL is incident on the optical system 522 (specifically, the fθ lens 5228). As described above, the return light RL is a light component that travels along the optical path of the measurement light ML among the light generated by the irradiation of the measurement light ML. Therefore, between the optical system 522 (particularly, the fθ lens 5228 having the terminal optical element) and the measurement object, the optical path of the return light RL may overlap with the optical path of the measurement light ML#2-2. In other words, between the optical system 522 and the measurement object, the optical path of the return light RL and the optical path of the measurement light ML#2-2 may be coaxial. For example, the fθ lens 5228 may irradiate the measurement object with the measurement light ML#2-2 so that the measurement light ML#2-2 is perpendicularly incident on the measurement object. The machine tool 1 may adjust the positional relationship between the fθ lens 5228 (i.e., the measurement head 52) and the measurement object by controlling at least one of the head drive system 3 and the stage drive system 42 so that the measurement light ML#2-2 is perpendicularly incident on the measurement object. When the measurement light ML#2-2 is perpendicularly incident on the measurement object, typically, the optical path of the return light RL overlaps with the optical path of the measurement light ML#2-2 between the optical system 522 and the measurement object. However, the fθ lens 5228 may irradiate the measurement light ML#2-2 onto the measurement object so that the measurement light ML#2-2 is obliquely incident on the measurement object. The machine tool 1 may adjust the positional relationship between the fθ lens 5228 and the measurement object by controlling at least one of the head drive system 3 and the stage drive system 42 so that the measurement light ML#2-2 is obliquely incident on the measurement object. Even in this case, as described above, the optical path of the return light RL, which is mainly composed of diffusely reflected light of the measurement light ML, overlaps with the optical path of the measurement light ML#2-2 between the optical system 522 and the measurement object.

[0082] When the optical path of the return light RL overlaps with the measurement light ML#2-2, the measurement device 5 may include a field stop (typically a pinhole) at a position optically conjugate with the surface of the measurement object (the focusing plane of the fθ lens 5228). In this case, the field stop can block multiple reflections that occur when the measurement light ML#2-2 is irradiated at one position on the measurement object and then reflected at another position on the measurement object, thereby reducing measurement errors. In this way, the field stop defines the optical path of the light component (return light RL) that travels along the optical path of the measurement light ML among the light generated by the irradiation of the measurement light ML. Here, the galvanometer mirror 5227 moves the position optically conjugate with the field stop within a plane that intersects with the optical axis AX of the fθ lens 5228. Therefore, the optical path of the return light RL from the surface of the measurement object to the galvanometer mirror 5227 also changes when the galvanometer mirror 5227 is driven. Instead of the field stop, the end of the optical fiber transmitting the measurement light ML#2-2 and the return light RL may be arranged at a position optically conjugate with the surface of the measurement object. However, between the optical system 522 and the measurement object, the optical path of the return light RL does not necessarily have to overlap with the optical path of the measurement light ML#2-2.

[0083] The return light RL incident on the fθ lens 5228 is incident on the detector 5226 via the galvanometer mirror 5227 and the beam splitters 5224 and 52212. Therefore, the detector 5226 may be considered to receive the return light RL via the fθ lens 5228.

[0084] As described above, in addition to the return light RL, the measurement light ML#1-3 is incident on the detector 5226. That is, the return light RL that travels toward the detector 5226 via the measurement object and the measurement light ML#1-3 that travels toward the detector 5226 without traveling through the measurement object are incident on the detector 5226. The detector 5226 detects the measurement light ML#1-3 and the return light RL. In particular, the detector 5226 detects interference light generated by the interference between the measurement light ML#1-3 and the return light RL. Note that the operation of receiving the interference light generated by the interference between the measurement light ML#1-3 and the return light RL is equivalent to the operation of receiving the measurement light ML#1-3 and the return light RL. The detection result of the detector 5226 (i.e., the reception result of the interference light) is output to the control device 7 via the output interface 53 as part of the measurement result of the measurement device 5.

[0085] The control device 7 acquires the detection results of the detector 5223 and the detection results of the detector 5226 via the output interface 53. The control device 7 generates measurement data of the measurement object (e.g., measurement data relating to at least one of the position and shape of the measurement object) based on the detection results of the detector 5223 and the detection results of the detector 5226 (i.e., the measurement results of the measuring device 5).

[0086] Specifically, since the pulse frequency of measurement light ML#1 is different from the pulse frequency of measurement light ML#2, the pulse frequency of measurement light ML#1-1 is different from the pulse frequency of measurement light ML#2-1. Therefore, the interference light between measurement light ML#1-1 and measurement light ML#2-1 is interference light in which pulse light appears in synchronization with the timing when the pulse light constituting measurement light ML#1-1 and the pulse light constituting measurement light ML2#2-1 simultaneously enter the detector 5223. Similarly, the pulse frequency of measurement light ML#1-3 is different from the pulse frequency of return light RL. Therefore, the interference light between measurement light ML#1-3 and return light RL is interference light in which pulse light appears in synchronization with the timing when the pulse light constituting measurement light ML#1-3 and the pulse light constituting return light RL simultaneously enter the detector 5226. Here, the position (position on the time axis) of the pulsed light of interference light detected by detector 5226 varies depending on the positional relationship between the measurement head 52 and the measurement object (that is, essentially, the positional relationship between the processing head 2 and the measurement object). This is because the interference light detected by detector 5226 is interference light between return light RL heading toward detector 5226 via the measurement object and measurement light ML#1-3 heading toward detector 5226 without passing through the measurement object. On the other hand, the position (position on the time axis) of the pulsed light of interference light detected by detector 5223 does not vary depending on the positional relationship between the measurement head 52 and the measurement object (that is, essentially, the positional relationship between the processing head 2 and the measurement object). For this reason, it can be said that the time difference between the pulsed light of interference light detected by detector 5226 and the pulsed light of interference light detected by detector 5223 indirectly indicates the positional relationship between the measurement head 52 and the measurement object. Specifically, it can be said that the time difference between the pulsed light of interference light detected by detector 5226 and the pulsed light of interference light detected by detector 5223 indirectly indicates the distance between processing head 2 and the measurement object in the direction along the optical path of measurement light ML (that is, the direction along the traveling direction of measurement light ML). Therefore, the control device 7 can calculate the distance between measurement head 52 and the measurement object in the direction along the optical path of measurement light ML (for example, the Z-axis direction) based on the time difference between the pulsed light of interference light detected by detector 5226 and the pulsed light of interference light detected by detector 5223.In other words, the control device 7 can calculate the position of the measurement object in a direction along the optical path of the measurement light ML (e.g., the Z-axis direction). More specifically, the control device 7 can calculate the distance between the measurement head 52 and an irradiated portion of the measurement object irradiated with the measurement light ML#2-2. The control device 7 can calculate the position of the irradiated portion in a direction along the optical path of the measurement light ML (e.g., the Z-axis direction). Furthermore, because the irradiation position of the measurement light ML#2-2 on the measurement object is determined by the drive state of the galvanometer mirror 5227, the control device 7 can calculate the position of the irradiated portion in a direction intersecting the optical path of the measurement light ML (e.g., at least one of the X-axis direction and the Y-axis direction) based on the drive state of the galvanometer mirror 5227. As a result, the control device 7 can generate measurement data indicating the position of the irradiated portion (e.g., the position in a three-dimensional coordinate space).

[0087] In this embodiment, the optical system 522 is attached to the processing head 2. As a result, the positional relationship between the fθ lens 5228 and the detector 5226 included in the optical system 522 is fixed regardless of the movement of the processing head 2. Therefore, the measurement error of the measurement device 5 is smaller than when the positional relationship between the fθ lens 5228 and the detector 5226 changes as the processing head 2 moves. This is because if the positional relationship between the fθ lens 5228 and the detector 5226 changes, the position (position on the time axis) of the pulsed interference light detected by the detector 5226 may change even if the distance between the measurement head 52 and the measurement object has not changed. As a result, a technical problem may occur in which the distance calculated by the control device 7 based on the detection result by the detector 5226 changes even if the distance between the measurement head 52 and the measurement object has not changed. However, if the positional relationship between the fθ lens 5228 and the detector 5226 is fixed, such a technical problem does not occur. Therefore, the control device 7 can calculate the position of the measurement object with high accuracy.

[0088] The control device 7 that calculates the position of the measurement object in this manner may be called a position calculation device. A system including the control device 7 and at least one of the reference member FM and the measuring device 5 may be called a position calculation system.

[0089] The measurement head 52 may irradiate multiple portions of the measurement object with the measurement light ML#2-2. For example, the galvanometer mirror 5227 may change the irradiation position of the measurement light ML#2-2 on the measurement object so that the measurement head 52 irradiates multiple portions of the measurement object with the measurement light ML#2-2. For example, at least one of the processing head 2 and the stage 41 may move so that the measurement head 52 irradiates multiple portions of the measurement object with the measurement light ML#2-2. When the measurement light ML#2-2 irradiates multiple portions of the measurement object, the control device 7 can generate measurement data indicating the positions of the multiple portions of the measurement object. As a result, the control device 7 can generate measurement data indicating the shape of the measurement object based on the measurement data indicating the positions of the multiple portions. For example, the control device 7 can generate measurement data indicating the shape of the measurement object by calculating a three-dimensional shape composed of virtual planes (or curved surfaces) connecting the multiple portions whose positions have been identified as the shape of the measurement object.

[0090] As described above, when the fθ lens 5228 is a telecentric optical system on the measurement object side, the traveling direction of the measurement light ML#2-2 emitted from the fθ lens 5228 is parallel to the optical axis AX of the fθ lens 5228. Therefore, when the measurement light ML#2-2 is irradiated onto multiple portions of the measurement object, the traveling direction of the measurement light ML#2-2 does not change. As a result, even when the measurement light ML#2-2 is irradiated onto multiple portions of the measurement object, the control device 7 can appropriately calculate the distance between the measurement head 52 and the measurement object (i.e., the position of the measurement object) in the direction along the traveling direction of the measurement light ML (i.e., the direction along the optical path of the measurement light ML). The control device 7 may previously determine the telecentricity error of the fθ lens 5228 (for example, the in-plane variation of the telecentricity error) and reflect the error in the measurement result.

[0091] In this way, the measurement device 5 can measure the measurement object by irradiating the measurement light ML onto the measurement object and detecting the return light RL from the measurement object irradiated with the measurement light ML. In particular, in the example described above, the measurement device 5 can measure the measurement object by detecting the interference light between the return light RL and the measurement light ML#1-3, which is the reference light. For this reason, the measurement device 5 may be considered to be an interferometric measurement device. However, the measurement device 5 does not have to be an interferometric measurement device as long as it can measure the measurement object. For example, the measurement device 5 may be a triangulation measurement device. The measurement device 5 may be a stereo measurement device. The measurement device 5 may be a phase-shift measurement device. The measurement device 5 may be a confocal measurement device. The measurement device 5 may be a ToF (Time of Flight) measurement device. The measurement device 5 may be an FMCW (Frequency Modulated Continuous Wave) measurement device.

[0092] (2) Movement error calculation operation Next, the movement error calculation operation performed by the control device 7 will be described.

[0093] (2-1) Overview of movement error calculation operation As described above, the movement error calculation operation is an operation for calculating a movement error occurring in the movement of at least one of the processing head 2 and the stage 41 based on the measurement results by the measurement device 5. As described above, the measurement device 5 receives interference light between the measurement light ML and the return light RL, and therefore the movement error calculation operation may be considered to be an operation for calculating a movement error occurring in the movement of at least one of the processing head 2 and the stage 41 based on the detection results of the interference light between the measurement light ML and the return light RL. In the following description, the processing head 2 and the stage 41, for which movement errors are calculated, are collectively referred to as error calculation objects, as necessary. Furthermore, the head drive system 3 and the stage drive system 42, which move the processing head 2 and the stage 41, respectively, are collectively referred to as drive systems.

[0094] The movement error may include an error corresponding to the difference (i.e., deviation) between the actual movement amount of the error calculation object when the drive system moves the error calculation object and a target value for the movement amount of the error calculation object. Specifically, the movement error may include an error corresponding to the difference (i.e., deviation) between the actual movement amount of the error calculation object in one movement direction and a target value for the movement amount of the error calculation object in one movement direction when the drive system moves the error calculation object along one movement direction. For example, if the drive system moves the error calculation object so that the error calculation object moves by one movement amount only along one movement direction, the movement error may include an error corresponding to the difference between the actual movement amount of the error calculation object in one movement direction and the one movement amount.

[0095] The movement error may include an error corresponding to the actual movement amount of the error calculation object in a movement direction other than the one movement direction when the drive system moves the error calculation object along that direction. For example, when the drive system moves the error calculation object so that the error calculation object moves only along one movement direction, ideally the error calculation object will not move along any other movement direction. Therefore, when an error calculation object that should move in one movement direction actually moves along the other movement direction, a movement error of the error calculation object in the other movement direction occurs. In other words, a movement error corresponding to the movement amount of the error calculation object in the other movement direction occurs.

[0096] When the error calculation target object moves along one movement direction in this way, there is a possibility that at least one of a movement error in one movement direction and a movement error in another movement direction occurs. Therefore, the control device 7 may calculate at least one of a movement error in one movement direction and a movement error in another movement direction that occurs in the movement of the error calculation target object along the one movement direction.

[0097] When the drive system moves the error calculation target object along the X-axis direction, which is the linear direction, as shown in FIG. 9 which shows an example of the movement error, the control device 7 calculates the movement error E X The movement error E X is the movement error E in the X-axis direction XX and the Y-axis movement error E YX and the Z-axis movement error E ZX and the rotational movement error around the A axis, E AX and the rotational movement error around the B axis E BX and the rotational movement error around the C axis E CX The movement error E XX The movement error E may be the difference between the actual movement amount of the error calculation object in the X-axis direction and the target value of the movement amount of the error calculation object in the X-axis direction when the drive system moves the error calculation object along the X-axis direction. YX may be the actual movement amount of the error calculation target object in the Y-axis direction when the drive system moves the error calculation target object along the X-axis direction. ZX may be the actual movement amount of the object for which error calculation is to be performed in the Z-axis direction when the drive system moves the object for which error calculation is to be performed in the X-axis direction. AX may be the actual movement amount (rotation amount) of the error calculation target object in the rotation direction around the A axis when the drive system moves the error calculation target object along the X axis direction. BX may be the actual movement amount (rotation amount) of the error calculation target object in the rotation direction around the B axis when the drive system moves the error calculation target object along the X axis direction. CX may be the actual movement amount (rotation amount) of the error calculation target object in the rotation direction around the C axis when the drive system moves the error calculation target object along the X axis direction.

[0098] When the drive system moves the error calculation object along the Y-axis direction, which is the linear direction, as shown in FIG. 9, the control device 7 calculates the movement error E Y The movement error E Y is the movement error E in the X-axis direction XY and the Y-axis movement error E YY and the Z-axis movement error E ZY and the rotational movement error around the A axis, E AY and the rotational movement error around the B axis E BY and the rotational movement error around the C axis E CY The movement error E XY may be the actual movement amount of the object for which error calculation is to be performed in the X-axis direction when the drive system moves the object for which error calculation is to be performed in the Y-axis direction. YY The movement error E may be the difference between the actual movement amount of the error calculation object in the Y-axis direction and the target value of the movement amount of the error calculation object in the Y-axis direction when the drive system moves the error calculation object along the Y-axis direction. ZY may be the actual movement amount of the error calculation target object in the Z-axis direction when the drive system moves the error calculation target object along the Y-axis direction. AY may be the actual movement amount (rotation amount) of the error calculation target object in the rotation direction around the A axis when the drive system moves the error calculation target object along the Y axis direction. BY may be the actual movement amount (rotation amount) of the error calculation target object in the rotation direction around the B axis when the drive system moves the error calculation target object along the Y axis direction. CY may be the actual movement amount (rotation amount) of the error calculation target object in the rotation direction around the C axis when the drive system moves the error calculation target object along the Y axis direction.

[0099] When the drive system moves the error calculation object along the Z-axis direction, which is the linear direction, as shown in FIG. 9, the control device 7 calculates the movement error EZ The movement error E Z is the movement error E in the X-axis direction XZ and the Y-axis movement error E YZ and the Z-axis movement error E ZZ and the rotational movement error around the A axis, E AZ and the rotational movement error around the B axis E BZ and the rotational movement error around the C axis E CZ The movement error E XZ may be the actual movement amount of the object for which error calculation is to be performed in the X-axis direction when the drive system moves the object for which error calculation is to be performed in the Z-axis direction. YZ may be the actual movement amount of the error calculation target object in the Y-axis direction when the drive system moves the error calculation target object along the Z-axis direction. ZZ The movement error E may be the difference between the actual movement amount of the error calculation object in the Z-axis direction when the drive system moves the error calculation object along the Z-axis direction and the target value of the movement amount of the error calculation object in the Z-axis direction. AZ may be the actual movement amount (rotation amount) of the error calculation target object in the rotation direction around the A axis when the drive system moves the error calculation target object along the Z axis direction. BZ may be the actual movement amount (rotation amount) of the error calculation target object in the rotation direction around the B axis when the drive system moves the error calculation target object along the Z axis direction. CZ may be the actual movement amount (rotation amount) of the error calculation target object in the rotation direction around the C axis when the drive system moves the error calculation target object along the Z axis direction.

[0100] When the drive system moves (i.e., rotates) the error calculation object along the rotation direction around the A axis, as shown in FIG. 9, the control device 7 calculates the movement error E A The movement error E A is the movement error E in the X-axis direction XA and the Y-axis movement error E YAand the Z-axis movement error E ZA and the rotational movement error around the A axis, E AA and the rotational movement error around the B axis E BA and the rotational movement error around the C axis E CA The movement error E XA may be the actual movement amount of the object for which error calculation is to be performed in the X-axis direction when the drive system moves the object for which error calculation is to be performed in the rotation direction around the A-axis. YA may be the actual movement amount of the object for which error calculation is to be performed in the Y-axis direction when the drive system moves the object for which error calculation is to be performed in the rotation direction around the A-axis. ZA may be the actual movement amount of the object for which error calculation is to be performed in the Z-axis direction when the drive system moves the object for which error calculation is to be performed in the rotation direction around the A-axis. AA may be the difference between the actual movement amount of the error calculation object in the rotation direction around the A axis and the target value of the movement amount of the error calculation object in the rotation direction around the A axis when the drive system moves the error calculation object in the rotation direction around the A axis. BA may be the actual movement (rotation) amount of the error calculation object in the rotation direction around the B axis when the drive system moves the error calculation object in the rotation direction around the A axis. CA may be the actual movement amount (rotation amount) of the error calculation target object in the rotation direction around the C axis when the drive system moves the error calculation target object in the rotation direction around the A axis.

[0101] When the drive system moves (i.e., rotates) the error calculation object along the rotation direction around the B axis, as shown in FIG. 9, the control device 7 calculates the movement error E B The movement error E B is the movement error E in the X-axis direction XB and the Y-axis movement error E YB and the Z-axis movement error E ZB and the rotational movement error around the A axis, E ABand the rotational movement error around the B axis E BB and the rotational movement error around the C axis E CB The movement error E XB may be the actual movement amount of the object for which error calculation is to be performed in the X-axis direction when the drive system moves the object for which error calculation is to be performed in the rotation direction around the B-axis. YB may be the actual movement amount of the object for which error calculation is to be performed in the Y-axis direction when the drive system moves the object for which error calculation is to be performed in the rotation direction around the B-axis. ZB may be the actual movement amount of the object for which error calculation is to be performed in the Z-axis direction when the drive system moves the object for which error calculation is to be performed in the rotation direction around the B-axis. AB may be the actual movement amount (rotation amount) of the error calculation target object in the rotation direction around the A axis when the drive system moves the error calculation target object in the rotation direction around the B axis. BB may be the difference between the actual movement amount of the error calculation object in the rotation direction around the B axis and the target value of the movement amount of the error calculation object in the rotation direction around the B axis when the drive system moves the error calculation object in the rotation direction around the B axis. CB may be the actual movement amount (rotation amount) of the error calculation target object in the rotation direction around the C axis when the drive system moves the error calculation target object in the rotation direction around the B axis.

[0102] When the drive system moves (i.e., rotates) the error calculation object along the rotation direction around the C axis, as shown in FIG. 9, the control device 7 calculates the movement error E C The movement error E C is the movement error E in the X-axis direction XC and the Y-axis movement error E YC and the Z-axis movement error E ZC and the rotational movement error around the A axis, E AC and the rotational movement error around the B axis E BC and the rotational movement error around the C axis ECC The movement error E XC may be the actual movement amount of the object for which error calculation is to be performed in the X-axis direction when the drive system moves the object for which error calculation is to be performed in the rotation direction around the C-axis. YC may be the actual movement amount of the object for which error calculation is to be performed in the Y-axis direction when the drive system moves the object for which error calculation is to be performed in the rotation direction around the C-axis. ZC may be the actual movement amount of the object for which error calculation is to be performed in the Z-axis direction when the drive system moves the object for which error calculation is to be performed in the rotation direction around the C-axis. AC may be the actual movement amount (rotation amount) of the error calculation target object in the rotation direction around the A axis when the drive system moves the error calculation target object in the rotation direction around the XC axis. BC may be the actual movement amount (rotation amount) of the error calculation target object in the rotation direction around the B axis when the drive system moves the error calculation target object in the rotation direction around the C axis. CC may be the difference between the actual movement amount of the error calculation object in the rotation direction about the C axis and the target value of the movement amount of the error calculation object in the rotation direction about the C axis when the drive system moves the error calculation object in the rotation direction about the C axis.

[0103] Furthermore, the movement error E XX , movement error E YY and movement error E ZZ Each of these may be referred to as a translation error or a linear positioning error. YX , movement error E ZX , movement error E XY , movement error E ZY , movement error E XZ and movement error E YZ Each of these may be referred to as a translation error or straightness error. AX , movement error E AY and movement error E AZ Each of these may be referred to as an attitude error or a roll error. BX , movement error E BY and movement error EBZ Each of the errors E may be referred to as an attitude error or a pitch error. CX , movement error E CY and movement error E CZ Each of these may be referred to as an attitude error or a yaw error. YA , movement error E ZA , movement error E XB , movement error E ZB , movement error E XC and movement error E YC Each of these may be referred to as a radial error. XA , movement error E YB and movement error E ZC Each of these may be referred to as an axial error. BA , movement error E CA , movement error E AB , movement error E CB , movement error E AC and movement error E BC Each of these may be referred to as a tilt direction error. AA , movement error E BB and movement error E CC Each of these may be referred to as an angular positioning error.

[0104] As an example, as described above, the head drive system 3 moves the processing head 2 along the X-axis direction. Therefore, the control device 7 calculates, as the movement error of the processing head 2, a movement error E X That is, the control device 7 may calculate the movement error E XX , movement error E YX , movement error E ZX , movement error E AX , movement error E BX and movement error E CX At least one of the following may be calculated.

[0105] As another example, as described above, the head drive system 3 moves the processing head 2 along the Z-axis direction. Therefore, the control device 7 calculates, as the movement error of the processing head 2, a movement error E Z That is, the control device 7 may calculate the movement error E XZ , movement error E YZ , movement error E ZZ , movement error E AZ , movement error E BZ and movement error E CZ At least one of the following may be calculated.

[0106] As another example, as described above, the stage drive system 42 moves the stage 41 along the Y-axis direction. Therefore, the control device 7 calculates, as the movement error of the stage 41, a movement error E Y That is, the control device 7 may calculate the movement error E XY , movement error E YY , movement error E ZY , movement error E AY , movement error E BY and movement error E CY At least one of the following may be calculated.

[0107] As another example, as described above, the stage drive system 42 moves the stage 41 in the rotation direction around the A axis. Therefore, the control device 7 calculates, as the movement error of the stage 41, a movement error E A That is, the control device 7 may calculate the movement error E XA , movement error E YA , movement error E ZA , movement error E AA , movement error E BA and movement error E CA At least one of the following may be calculated.

[0108] As another example, as described above, the stage drive system 42 moves the stage 41 in the rotation direction around the C axis. Therefore, the control device 7 calculates, as the movement error of the stage 41, a movement error E C That is, the control device 7 may calculate the movement error E XC , movement error E YC , movement error E ZC , movement error E AC , movement error E BC and movement error E CC At least one of the following may be calculated.

[0109] When the head drive system 3 moves the processing head 2 along two movement directions, the control device 7 may calculate a movement error related to the relationship between two movement axes along each of the two movement directions. Similarly, when the stage drive system 42 moves the stage 41 along two movement directions, the control device 7 may calculate a movement error related to the orthogonality of the two movement axes along each of the two movement directions. As an example, when the head drive system 3 moves the processing head 2 along two linear directions and / or the stage drive system 42 moves the stage 42 along two linear directions, the control device 7 may calculate a movement error related to the orthogonality of the two movement axes along each of the two linear directions. For example, the control device 7 may calculate a movement error related to the orthogonality of at least two of the movement axes along the X-axis, the Y-axis, and the Z-axis. As another example, when the head drive system 3 moves (rotates) the processing head 2 along two rotational directions and / or the stage drive system 42 moves (rotates) the stage 42 along two rotational directions, the control device 7 may calculate a movement error related to the orthogonality of two rotational axes that respectively define the two rotational directions. For example, the control device 7 may calculate a movement error related to the orthogonality of at least two of the rotational axis around the A-axis, the rotational axis around the B-axis, and the rotational axis around the C-axis. As another example, when the head drive system 3 moves (rotates) the processing head 2 along one linear direction and one rotational direction and / or the stage drive system 42 moves (rotates) the stage 42 along one linear direction and one rotational direction, the control device 7 may calculate a movement error related to the orthogonality of the movement axis along the one linear direction and the rotational axis that respectively defines the one rotational direction. For example, the control device 7 may calculate a movement error related to the orthogonality of the movement axis along the X-axis and at least one of the rotational axis around the B-axis and the rotational axis around the C-axis. For example, the control device 7 may calculate a movement error related to the orthogonality between a movement axis along the Y axis and at least one of the rotation axis about the A axis and the rotation axis about the C axis. For example, the control device 7 may calculate a movement error related to the orthogonality between a movement axis along the Z axis and at least one of the rotation axis about the A axis and the rotation axis about the B axis.As another example, when the head drive system 3 moves (rotates) the processing head 2 along one linear direction and one rotational direction and / or the stage drive system 42 moves (rotates) the stage 42 along one linear direction and one rotational direction, the control device 7 may calculate a movement error related to the parallelism between the movement axis along the one linear direction and the rotation axis that defines the one rotational direction. For example, the control device 7 may calculate a movement error related to the parallelism between the movement axis along the X-axis and the rotation axis about the A-axis. For example, the control device 7 may calculate a movement error related to the parallelism between the movement axis along the Y-axis and the rotation axis about the B-axis. For example, the control device 7 may calculate a movement error related to the parallelism between the movement axis along the Z-axis and the rotation axis about the C-axis.

[0110] In this embodiment, to calculate the movement error, as shown in FIG. 10 , a reference member FM, which is different from the workpiece W to be machined by the machining head 2, is placed on the stage 41, and the measurement device 5 measures at least a portion of the reference member FM placed on the stage 41. That is, the measurement device 5 irradiates at least a portion of the reference member FM with measurement light ML and detects return light RL from at least a portion of the reference member FM. Thereafter, the control device 7 calculates the position of at least a portion of the reference member FM based on the measurement results by the measurement device 5 (that is, the detection results of the interference light between the measurement light ML and the return light RL). Thereafter, the control device 7 calculates the movement error based on the calculation results of the position of at least a portion of the reference member FM. Note that a specific example of the operation of calculating the movement error based on the calculation results of the position of at least a portion of the reference member FM will be described in detail later.

[0111] The measurement device 5 may measure at least a portion of the surface of the reference member FM that is irradiated with the measurement light ML (hereinafter referred to as the "reference surface FMS"). That is, the measurement device 5 may irradiate at least a portion of the reference surface FMS with the measurement light ML and detect the return light RL from at least a portion of the reference surface FMS. The control device 7 may then calculate the position of at least a portion of the reference surface FMS based on the measurement results by the measurement device 5 (that is, the detection results of the interference light between the measurement light ML and the return light RL). The control device 7 may then calculate a movement error based on the calculation results of the position of at least a portion of the reference surface FMS.

[0112] The measurement head 52 may use the galvanometer mirror 5227 to change the irradiation position of the measurement light ML on the reference member FM. That is, the measurement head 52 may irradiate different measurement target regions of the reference member FM with the measurement light ML. In the example shown in FIG. 10, the measurement head 52 irradiates one measurement target region P1 and another measurement target region P2 that are different from each other with the measurement light ML. In this case, the measurement light ML that travels from the galvanometer mirror 5227 in one traveling direction TD1 and enters the fθ lens 5228 may travel along one optical path OP1 and be irradiated onto one measurement target region P1 on the reference member FM (i.e., one position on the reference member FM). Furthermore, of the light from one measurement target region P1 generated by the measurement light ML irradiated onto one measurement target region P1, a light component that travels along one optical path OP1 enters the measurement head 52 (particularly, its detector 5226) as returned light RL. On the other hand, the measurement light ML that travels from the galvanometer mirror 5227 in another traveling direction TD2 different from the first traveling direction TD1 and enters the fθ lens 5228 may travel along another optical path OP2 different from the first optical path OP1 and be irradiated onto another measurement target region P2 of the reference member FM (i.e., another position on the reference member FM). Furthermore, of the light from the other measurement target region P2 generated by the measurement light ML irradiated onto the other measurement target region P2, a light component traveling along the other optical path OP2 is incident on the measurement head 52 (particularly its detector 5226) as returned light RL. Thereafter, the control device 7 may calculate the positions of multiple measurement target regions (e.g., measurement target regions P1 and P2) based on the measurement results by the measurement device 5. Thereafter, the control device 7 may calculate a movement error based on the calculation results of the positions of the multiple measurement target regions.

[0113] While the galvanometer mirror 5227 is changing the irradiation position of the measurement light ML on the reference member FM, the processing head 2 and the stage 41 may each be stationary. That is, the head drive system 3 does not have to move the processing head 2, and the stage drive system 42 does not have to move the stage 41. Because the measurement head 52 is attached to the processing head 2, the measurement head 52 may also be stationary while the galvanometer mirror 5227 is changing the irradiation position of the measurement light ML on the reference member FM. In this case, the position of the measurement head 52 (particularly the fθ lens 5228) when the measurement light ML is irradiated from the fθ lens 5228 to one position on the reference member FM may be the same as the position of the measurement head 52 (particularly the fθ lens 5228) when the measurement light ML is irradiated from the fθ lens 5228 to another position on the reference member FM. That is, when the measurement light ML is irradiated from the fθ lens 5228 onto a first position on the reference member FM, the measurement head 52 (particularly the fθ lens 5228) may be located at the third position, and when the measurement light ML is irradiated from the fθ lens 5228 onto a second position on the reference member FM, the measurement head 52 (particularly the fθ lens 5228) may remain located at the same third position. In this case, it is possible to reduce measurement errors that occur due to movement of at least one of the processing head 2 and the stage 41 during the period when the galvanometer mirror 5227 is changing the irradiation position of the measurement light ML on the reference member FM.

[0114] When calculating a movement error that occurs in the movement of the machining head 2 or the stage 41 when the machining head 2 or the stage 41 moves along one movement direction, the drive system may move the machining head 2 or the stage 41 in one movement direction. In other words, the drive system may change the positional relationship between the machining head 2 and the stage 41 in one movement direction by moving the machining head 2 or the stage 41 in one movement direction. The measuring device 5 may measure the reference member FM before the machining head 2 or the stage 41 moves in one movement direction, and measure the reference member FM after the machining head 2 or the stage 41 moves in one movement direction. In other words, the measuring device 5 may measure the reference member FM before the positional relationship between the machining head 2 and the stage 41 in one movement direction is changed, and measure the reference member FM after the positional relationship between the machining head 2 and the stage 41 in one movement direction is changed. Even in this case, the machining head 2 and the stage 41 may be stationary while the measuring device 5 is measuring the reference member FM. That is, the measuring device 5 may measure the reference member FM in a state where the processing head 2 and the stage 41 are stationary.

[0115] As an example, when the processing head 2 moves along the Z-axis direction, a movement error E ZWhen calculating the distance Φ, the head drive system 3 may move the machining head 2 along the Z-axis direction. That is, the head drive system 3 may change the positional relationship between the machining head 2 and the stage 41 in the Z-axis direction by moving the machining head 2 along the Z-axis direction. For example, the head drive system 3 may change the positional relationship between the machining head 2 and the stage 41 in the Z-axis direction from the relationship shown in FIG. 11(a) to a second relationship shown in FIG. 11(b). FIG. 11(a) shows an example in which the distance between the machining head 2 and the stage 41 in the Z-axis direction is distance D1. FIG. 11(b) shows an example in which the distance between the machining head 2 and the stage 41 in the Z-axis direction is distance D2, which is different from distance D1. In this case, the measuring device 5 may measure the reference member FM in the state shown in FIG. 11(a) and also measure the reference member FM in the state shown in FIG. 11(b). Specifically, the measurement device 5 may irradiate the reference member FM with measurement light ML and receive return light RL from the reference member FM in the state shown in Fig. 11(a). Similarly, the measurement device 5 may irradiate the reference member FM with measurement light ML and receive return light RL from the reference member FM in the state shown in Fig. 11(b).

[0116] As another example, when the stage 41 moves along the Y-axis, a movement error E YWhen calculating , the stage drive system 42 may move the stage 41 along the Y-axis direction. That is, the stage drive system 42 may change the positional relationship between the processing head 2 and the stage 41 in the Y-axis direction by moving the stage 41 along the Y-axis direction. For example, the stage drive system 42 may change the positional relationship between the processing head 2 and the stage 41 in the Y-axis direction from the relationship shown in FIG. 12(a) to the relationship shown in FIG. 12(b). In this case, the measurement device 5 may measure the reference member FM in the state shown in FIG. 12(a) and measure the reference member FM in the state shown in FIG. 12(b). Specifically, the measurement device 5 may irradiate the reference member FM with measurement light ML in the state shown in FIG. 12(a) and receive return light RL from the reference member FM. Similarly, the measurement device 5 may irradiate the reference member FM with measurement light ML and receive return light RL from the reference member FM in the state shown in FIG. 12(b).

[0117] 11(a) and 11(b), the processing head 2 moves along the Z-axis direction, which is a direction along the optical path of the measurement light ML emitted from the measurement head 52 (i.e., emitted from the fθ lens 5228). In other words, the processing head 2 moves along the Z-axis direction, which is a direction in which the optical axis AX of the fθ lens 5228 extends. On the other hand, in FIGS. 12(a) and 12(b), the stage 41 moves along the Y-axis direction, which is a direction intersecting the optical path of the measurement light ML emitted from the measurement head 52 (i.e., emitted from the fθ lens 5228). In other words, the stage 41 moves along the Y-axis direction, which is a direction intersecting the direction in which the optical axis AX of the fθ lens 5228 extends. In this way, the processing head 2 or the stage 41 may move along a direction along the optical path of the measurement light ML, or may move along a direction intersecting the optical path of the measurement light ML. In other words, the processing head 2 or the stage 41 may move along the direction in which the optical axis AX of the fθ lens 5228 extends, or along a direction intersecting the direction in which the optical axis AX of the fθ lens 5228 extends.

[0118] 11(a) and 11(b), the optical paths of the measurement light ML and return light RL in the state shown in FIG. 11(a) are at least partially different from the optical paths of the measurement light ML and return light RL in the state shown in FIG. 11(b). Specifically, the lengths of the optical paths of the measurement light ML and return light RL in the state shown in FIG. 11(a) are different from the lengths of the optical paths of the measurement light ML and return light RL in the state shown in FIG. 11(b). On the other hand, in FIGS. 12(a) and 12(b), the optical paths of the measurement light ML and return light RL in the state shown in FIG. 12(a) are the same as the optical paths of the measurement light ML and return light RL in the state shown in FIG. 12(b). In this way, the optical paths of the measurement light ML and return light RL before the processing head 2 or stage 41 moves may be the same as or different from the optical paths of the measurement light ML and return light RL after the processing head 2 or stage 41 moves. As one example, when the processing head 2 or the stage 41 moves along the optical path of the measurement light ML, the optical paths of the measurement light ML and the return light RL before the processing head 2 moves may be different from the optical paths of the measurement light ML and the return light RL after the processing head 2 moves. This is because the lengths of the optical paths of the measurement light ML and the return light RL change as the processing head 2 or the stage 41 moves. As another example, when the processing head 2 moves in a direction intersecting the optical path of the measurement light ML, the optical paths of the measurement light ML and the return light RL before the processing head 2 moves may be different from the optical paths of the measurement light ML and the return light RL after the processing head 2 moves. As another example, when the stage 41 moves in a direction intersecting the optical path of the measurement light ML, the optical paths of the measurement light ML and the return light RL before the stage 41 moves may be the same as the optical paths of the measurement light ML and the return light RL after the stage 41 moves. However, when the reference member FM2 or FM3 described later is used as the reference member FM, even if the stage 41 moves along a direction that intersects with the optical path of the measurement light ML, the optical paths of the measurement light ML and the return light RL before the stage 41 moves may be different from the optical paths of the measurement light ML and the return light RL after the stage 41 moves.

[0119] As described above, the control device 7 calculates the distance between the measurement head 52 and the measurement object in the direction along the optical path of the measurement light ML (i.e., the position of the measurement object) based on the measurement results by the measurement device 5. In this case, the processing head 2 or the stage 41 may move so that the distance between the processing head 2 and the stage 41 in the direction along the optical path of the measurement light ML (i.e., the distance between the measurement head 52 and the reference member FM) changes. In particular, when the processing head 2 or the stage 41 is moved in the X-axis direction, Y-axis direction, or Z-axis direction, the processing head 2 or the stage 41 may move so that the distance between the measurement head 52 and the reference member FM in the direction along the optical path of the measurement light ML changes. In this case, the control device 7 can appropriately calculate the change in the distance between the measurement head 52 and the reference member FM caused by the movement of the processing head 2 or the stage 41. As a result, the control device 7 detects a measurement error (for example, a movement error E XX , movement error E YY and movement error E ZZ ) can be calculated appropriately.

[0120] 11(a) and 11(b), the movement of the processing head 2 in the Z-axis direction changes the distance between the measurement head 52 and the reference member FM in the Z-axis direction, which is the direction along the optical path of the measurement light ML. Therefore, in the example shown in Figures 11(a) and 11(b), it can be said that the processing head 2 moves so that the movement of the processing head 2 in the Z-axis direction changes the distance between the measurement head 52 and the reference member FM in the Z-axis direction, which is the direction along the optical path of the measurement light ML.

[0121] 12(a) and 12(b), movement of the stage 41 in the Y-axis direction does not change the distance between the measurement head 52 and the reference member FM along the Z-axis direction, which is the direction along the optical path of the measurement light ML. Therefore, in the example shown in Figures 12(a) and 12(b), it cannot be said that movement of the stage 41 in the Y-axis direction changes the distance between the measurement head 52 and the reference member FM in the Z-axis direction, which is the direction along the optical path of the measurement light ML. Therefore, in this case, the traveling direction of the measurement light ML may be changed by movement of the processing head 2 or the stage 41 so that the distance between the measurement head 52 and the reference member FM along the optical path of the measurement light ML changes.

[0122] As an example, as shown in FIG. 13 , the measurement head 52 may change the traveling direction of the measurement light ML using a deflection member 523 that deflects the measurement light ML emitted from the fθ lens 5228 toward the reference member FM. The deflection member 523 may be, for example, a mirror. In this case, the measurement light ML emitted from the measurement head 52 travels along the Y-axis direction, which is the movement direction of the stage 41. That is, the deflection member 523 deflects the measurement light ML so that the traveling direction of the measurement light ML is the same as or parallel to the direction in which the movement error is measured (the Y-axis direction). As a result, the stage 41 can be moved by moving the stage 41 in the Y-axis direction so that the distance between the measurement head 52 and the reference member FM in the Y-axis direction, which is the traveling direction of the measurement light ML, changes. In the example shown in FIG. 13 , the distance between the measurement head 52 and the reference member FM in the Y-axis direction changes from distance D3 to distance D4 by moving the stage 41 in the Y-axis direction. Note that in the example shown in FIG. 13 , the measurement head 52 includes the deflection member 523. That is, the deflection member 523 is housed in the head housing 521. However, the deflection member 523 may be disposed outside the head housing 521.

[0123] As another example, as shown in FIG. 14 , if at least one of the processing head 2 and the stage 41 is rotatable around a rotation axis, the traveling direction of the measurement light ML may be changed by rotating at least one of the processing head 2 and the stage 41 around the rotation axis. FIG. 14 shows an example in which the processing head 2 is rotated in a rotational direction around the X axis (i.e., in a rotational direction around the A axis) to change the traveling direction of the measurement light ML to the Y axis direction, which is the movement direction of the stage 41. In other words, the direction of the processing head 2 is set so that the traveling direction of the measurement light ML is the same as or parallel to the direction in which the movement error is measured (the Y axis direction). In this case, the stage 41 can be moved so that the distance between the measurement head 52 and the reference member FM in the Y axis direction, which is the traveling direction of the measurement light ML, changes as the stage 41 moves in the Y axis direction. In the example shown in FIG. 14 , the distance between the measurement head 52 and the reference member FM in the Y axis direction changes from distance D5 to distance D6 as the stage 41 moves in the Y axis direction.

[0124] When the traveling direction of the measurement light ML is changed, the orientation of the reference member FM placed on the stage 41 may also be changed in accordance with the traveling direction of the measurement light ML. Specifically, the orientation of the reference member FM placed on the stage 41 may be changed so that the measurement light ML, whose traveling direction has been changed, is irradiated onto the reference surface FMS of the reference member FM. Typically, the orientation of the reference member FM placed on the stage 41 may be changed so that the reference surface FMS becomes a plane intersecting with the traveling direction of the measurement light ML. In the example shown in FIGS. 13 and 14 , the orientation of the reference member FM placed on the stage 41 is changed so that the reference surface FMS becomes a plane intersecting with the Y-axis direction, which is the traveling direction of the measurement light ML (for example, a plane along the XZ plane). Note that the reference member FM is not limited to a flat member and may be a three-dimensional member. In this case, a reference member having multiple planes whose normals are oriented in different predetermined directions may be used. In this case, each of the multiple planes may be used as the reference surface FMS. For example, when a cubic reference member is used, the measurement device 5 may use the top surface of the reference member as one reference surface FMS to perform the measurement method shown in Figures 11 and 12, and may use the side surface of the reference member as another reference surface FMS to perform the measurement method shown in Figures 13 and 14.

[0125] Although detailed explanation will be omitted to avoid redundancy, the same can be said when the processing head 2 or the stage 41 moves along a movement direction different from the Y-axis direction and the Z-axis direction. Specifically, when the processing head 2 moves along the X-axis direction, the movement error E X When calculating the error E, the head drive system 3 moves the processing head 2 along the X-axis direction, and the measurement device 5 may measure the reference member FM both before and after the processing head 2 moves in the X-axis direction. AWhen calculating the error E, the stage drive system 42 moves the stage 41 in the rotation direction around the A axis, and the measurement device 5 may measure the reference member FM both before and after the stage 41 moves in the rotation direction around the A axis. C When calculating the reference member FM, the stage drive system 42 may move the stage 41 in the rotation direction around the C-axis, and the measurement device 5 may measure the reference member FM both before and after the stage 41 moves in the rotation direction around the C-axis. The movement direction of the processing head 2 or the stage 41 is not limited to the X-axis, Y-axis, and Z-axis directions. For example, the movement direction of the processing head 2 or the stage 41 may be set along an axis along which at least two of the coordinate values ​​in the X-axis direction, the Y-axis direction, and the Z-axis direction change simultaneously (typically, an axis along a diagonal line connecting the vertices of an imaginary cube in the XYZ coordinate system). In the example of FIG. 13 , the angle of the deflection member 523 may be adjusted to set the traveling direction of the measurement light ML to be the same as or parallel to the movement direction of the processing head 2 or the stage 41. In the example of FIG. 14 , the angle of the reference member FM may be adjusted to set the traveling direction of the measurement light ML to be the same as or parallel to the movement direction of the processing head 2 or the stage 41.

[0126] Thereafter, the control device 7 may calculate the position of the reference member FM before the machining head 2 or the stage 41 moves and the position of the reference member FM after the machining head 2 or the stage 41 moves, based on the measurement results by the measurement device 5. Then, the control device 7 may calculate a movement error based on the calculated position of the reference member FM. For example, in the example shown in FIGS. 11(a) and 11(b), the movement error E ZIn this case, the control device 7 calculates the distance from the measurement head 52 to the reference member FM along the Z axis direction before the movement of the processing head 2 (i.e., the Z position of the reference member FM) from the detection result of the return light RL from the reference member FM before the movement of the processing head 2. Furthermore, the control device 7 calculates the distance from the measurement head 52 to the reference member FM along the Z axis direction after the movement of the processing head 2 (i.e., the Z position of the reference member FM) from the detection result of the return light RL from the reference member FM after the movement of the processing head 2. Here, the movement error E Z (In particular, the movement error E ZZ ) does not occur, the difference between the Z position of the reference member FM before the machining head 2 moves and the Z position of the reference member FM after the machining head 2 moves should match the target value of the movement amount of the machining head 2 in the Z-axis direction. Z (In particular, the movement error E ZZ ) occurs, the difference between the Z position of the reference member FM before the machining head 2 moves and the Z position of the reference member FM after the machining head 2 moves does not match the target value of the movement amount of the machining head 2 in the Z axis direction. Therefore, the control device 7 calculates the movement error E based on the position of the reference member FM. Z (In particular, the movement error E ZZ ) can be calculated. ZZ Other movement errors (i.e., movement error E XZ , movement error E YZ , movement error E AZ , movement error E BZ and movement error E CZ Similarly, information about the movement error is included in the measurement result by the measuring device 5 for at least one of the above. Therefore, the control device 7 determines the movement error E Z (For example, the movement error E XZ , movement error E YZ , movement error E AZ , movement error E BZ and movement error E CZSimilarly, even when the processing head 2 or the stage 41 moves in a direction different from the Z-axis direction, the control device 7 can calculate the movement error (for example, the movement error E X , movement error E Y , movement error E A , movement error E B and movement error E C It is possible to calculate the orthogonality between the X, Y and Z axes.

[0127] After calculating the movement error, the control device 7 may control the operation of the machine tool 1 based on the calculated movement error. For example, the control device 7 may control at least one of the head drive system 3 and the stage drive system 42 based on the calculated movement error so that even when a movement error exists, at least one of the machining head 2 and the stage 41 moves in the same way as when no movement error exists.

[0128] For example, the control device 7 may calibrate (in other words, correct or amend) the movement control information used to control the movement of at least one of the machining head 2 and the stage 41 based on the movement error. For example, the control device 7 may calibrate the movement control information based on the movement error so that at least one of the machining head 2 and the stage 41 moves in the same manner even when a movement error exists as when no movement error exists. In this case, the control device 7 may control the movement of at least one of the machining head 2 and the stage 41 based on the calibrated movement control information. Note that calibrating the movement control information may include correcting the movement control information so that the movement error after calibration is smaller than the movement error before calibration.

[0129] An example of the movement control information is movement path information (e.g., machining path information) indicating the movement path of at least one of the machining head 2 and the stage 41 in a reference coordinate system. The control device 7 typically uses the movement path information to control at least one of the head drive system 3 and the stage drive system 42 so that at least one of the machining head 2 and the stage 41 moves along the movement path indicated by the movement path information. The movement path information may include coordinate information indicating the movement path using coordinates (e.g., information indicating the coordinates of each position on the movement path). The movement path information may also include vector information indicating the movement path using vectors (e.g., information indicating the movement direction and movement amount at each position on the movement path). In this case, the control device 7 may calibrate the movement path information based on a movement error. For example, the control device 7 may calibrate the movement path information based on a movement error so that at least one of the machining head 2 and the stage 41 moves in the same way even when a movement error exists as when no movement error exists. In this case, the control device 7 may control at least one of the head drive system 3 and the stage drive system 42 based on the calibrated movement path information.

[0130] In addition to or instead of calibrating the movement path information based on the movement error, the control device 7 may calculate a calibration amount (in other words, a correction amount or amendment amount) for the movement path information based on the movement error. For example, the control device 7 may calculate a calibration amount for calibrating the movement path information so that at least one of the processing head 2 and the stage 41 moves in the same way as when no movement error exists, even when a movement error exists. In this case, the control device 7 may calibrate the movement path information based on the calculated calibration amount, and control at least one of the head drive system 3 and the stage drive system 42 based on the calibrated movement path information.

[0131] Another example of the movement control information is a drive command signal for operating at least one of the head drive system 3 and the stage drive system 42. The drive command signal may include, for example, a signal for driving a motor included in at least one of the head drive system 2 and the stage drive system 42. If the motor is a stepping motor, the drive command signal may include a signal specifying the number of steps (number of pulses). In this case, the control device 7 may calibrate the drive command signal generated based on the movement path information based on a movement error. For example, the control device 7 may calibrate the drive command signal generated based on the movement path information based on a movement error so that at least one of the processing head 2 and the stage 41 moves in the same manner as when there is no movement error, even when there is a movement error. In this case, the control device 7 may output the calibrated drive command signal to at least one of the head drive system 3 and the stage drive system 42. Alternatively, instead of calibrating the drive command signal generated based on the movement path information based on the movement error, the control device 7 may generate the drive command signal based on the movement error and the movement path information. That is, the control device 7 may generate a calibrated drive command signal based on the movement error and the movement path information.

[0132] As another example, in addition to or instead of calibrating the drive command signal based on the movement error, the control device 7 may calculate a calibration amount for the drive command signal based on the movement error. For example, the control device 7 may calculate a calibration amount for calibrating the drive command signal so that even when a movement error exists, at least one of the processing head 2 and the stage 41 moves in the same way as when no movement error exists. In this case, the control device 7 may calibrate the drive command signal based on the calculated calibration amount and output the calibrated drive command signal to at least one of the head drive system 3 and the stage drive system 42.

[0133] The control device 7 may output the calculated movement error using the output device 8. For example, the control device 7 may display an image indicating the calculated movement error using the output device 8 including a display device. For example, the control device 7 may output a sound indicating the calculated movement error using the output device 8 including an audio output device. For example, the control device 7 may output a paper sheet on which the calculated movement error is printed using the output device 8 including a printing device. For example, the control device 7 may output data indicating the calculated movement error to a recording medium using the output device 8. For example, the control device 7 may output (i.e., transmit) data indicating the calculated movement error to an external device using the output device 8 that can function as a communication device. In this case, an operator who confirms the movement error output by the output device 8 may control the machine tool 1 based on the movement error. An external device that acquires the movement error output by the output device 8 may control the machine tool 1 based on the movement error. Note that the control device 7 may output at least one of the calibrated movement control information and the calibration amount of the movement control information, in addition to the calculated movement error, using the output device 8.

[0134] The control device 7 may use the output device 8 to output measurement data indicating the calculated position of the reference member FM in order to calculate the movement error. For example, the control device 7 may use the output device 8 including a display device to display an image indicating the calculated position of the reference member FM. For example, the control device 7 may use the output device 8 including an audio output device to output audio indicating the calculated position of the reference member FM. For example, the control device 7 may use the output device 8 including a printing device to output a paper page on which the calculated position of the reference member FM is printed. For example, the control device 7 may use the output device 8 to output data indicating the calculated position of the reference member FM to a recording medium. For example, the control device 7 may use the output device 8 that can function as a communication device to output (i.e., transmit) data indicating the calculated position of the reference member FM to an external device. In this case, an operator who confirms the position of the reference member FM output by the output device 8 may calculate the movement error based on the position of the reference member FM. An operator who confirms the position of the reference member FM output by the output device 8 may control the machine tool 1 based on the position of the reference member FM. The movement error may be calculated by an external device that acquires the position of the reference member FM output by the output device 8. The machine tool 1 may be controlled by an external device that acquires the position of the reference member FM output by the output device 8.

[0135] (2-2) Example of movement error calculation operation Next, a specific example of the movement error calculation operation will be described. In this embodiment, the control device 7 may perform at least one of a movement error calculation operation using a first reference member FM (hereinafter referred to as "reference member FM1"), a movement error calculation operation using a second reference member FM (hereinafter referred to as "reference member FM2"), and a movement error calculation operation using a third reference member FM (hereinafter referred to as "reference member FM3"). Therefore, below, the movement error calculation operation using the reference member FM1, the movement error calculation operation using the reference member FM2, and the movement error calculation operation using the reference member FM3 will be described in order.

[0136] In the following description, the reference members FM1, FM2, and FM3 are used to calculate the movement error E ZThe movement error calculation operation will be described below. However, the control device 7 calculates the movement error E X , movement error E Y , movement error E A , movement error E B and movement error E C Even when calculating at least one of the following, the movement error E Z As a result, the control device 7 may perform the same operation as in the case of calculating the movement error E Z By performing the same operation as when calculating the movement error E X , movement error E Y , movement error E A , movement error E B and movement error E C At least one of the following may be calculated.

[0137] (2-2-1) Movement error calculation operation using reference member FM1 First, the movement error calculation operation using the reference member FM1 will be described.

[0138] An example of the reference member FM1 is shown in FIG. 15. As shown in FIG. 15, the reference member FM1 is a member on which a grid pattern GP of a predetermined shape is formed on a reference surface FMS. Specifically, a plurality of reference regions MA11 and a plurality of reference regions MA12 are formed on the reference surface FMS of the reference member FM1. The plurality of reference regions MA11 and the plurality of reference regions MA12 are arranged so as to form the grid pattern GP of a predetermined shape. In the example shown in FIG. 15, the plurality of reference regions MA11 and the plurality of reference regions MA12 are arranged along the reference surface FMS so that the reference regions MA11 and the reference regions MA12 are alternately arranged along each of two directions (e.g., the X-axis direction and the Y-axis direction) that are orthogonal to each other.

[0139] The plurality of reference regions MA11 and the plurality of reference regions MA12 in the grid pattern GP are not limited to being arranged in a checkerboard pattern on a plane. At least one of the plurality of reference regions MA11 and at least one of the plurality of reference regions MA12 may be arranged on different planes. Furthermore, the plurality of reference regions MA11 and the plurality of reference regions MA12 may be arranged along two directions that are not orthogonal to each other, or may not be arranged alternately.

[0140] The reference area MA11 and the reference area MA12 may be areas having different predetermined characteristics. The predetermined characteristic may be a characteristic that satisfies the condition that information regarding the difference between the predetermined characteristic of the reference area MA11 and the predetermined characteristic of the reference area MA12 is included in the measurement result by the measurement device 5. In other words, the predetermined characteristic may be a characteristic that satisfies the condition that the difference between the predetermined characteristic of the reference area MA11 and the predetermined characteristic of the reference area MA12 can be identified from the measurement result by the measurement device 5. For example, the predetermined characteristic may include a position in a direction intersecting the reference plane FMS (e.g., the Z-axis direction). In this case, information regarding the difference between the position of the reference area MA11 in the Z-axis direction and the position of the reference area MA12 in the Z-axis direction is included in the measurement result by the measurement device 5 as the difference between the distance between the measurement head 52 and the reference area MA11 in the Z-axis direction and the distance between the measurement head 52 and the reference area MA12 in the Z-axis direction. For example, the predetermined characteristic may include reflectance with respect to the measurement light ML. In this case, information regarding the difference between the reflectance of the reference area MA11 and the reflectance of the reference area MA12 is included in the measurement result by the measuring device 5 as the difference in the detected intensity of the return light RL at the detector 5226 (i.e., the difference in the detected intensity of the interference light). Note that two or more of the examples given as examples of the predetermined characteristics may be different at the same time. On the other hand, the multiple reference areas MA11 may be areas where the predetermined characteristics are the same. Similarly, the multiple reference areas MA12 may be areas where the predetermined characteristics are the same.

[0141] The measurement device 5 may measure at least five reference areas MA11 within the grid pattern GP, ​​as shown in Figures 16 and 17. Alternatively, the measurement device 5 may measure at least five reference areas MA12 within the grid pattern GP. In other words, the measurement device 5 may measure at least five reference areas within the grid pattern GP that have the same predetermined characteristics as described above as at least five measurement target areas. Note that, below, an example will be described in which the measurement device 5 measures five reference areas MA11 (specifically, reference area MA11c, reference area MA11x+, reference area MA11x-, reference area MA11y+, and reference area MA11y-).

[0142] The measurement device 5 may use the galvanometer mirror 5227 to change the irradiation position of the measurement light ML on the reference surface FMS, thereby irradiating the measurement light ML onto each of the reference region MA11c, the reference region MA11x+, the reference region MA11x-, the reference region MA11y+, and the reference region MA11y-. Therefore, the reference region MA11c, the reference region MA11x+, the reference region MA11x-, the reference region MA11y+, and the reference region MA11y- may be included in a scanning region that the galvanometer mirror 5227 can scan with the measurement light ML while the positional relationship between the measurement head 52 and the reference member FM is fixed. Specifically, as shown in FIG. 17 , the measurement head 52 may irradiate the measurement light ML traveling from the fθ lens 5228 along the optical path OP11 onto the reference region MA11c. Furthermore, the measurement head 52 may receive, as returned light RL from the reference area MA11c, a light component of light from the reference area MA11c generated by the measurement light ML irradiated onto the reference area MA11c and traveling along the optical path OP11. Furthermore, the measurement head 52 may irradiate the reference area MA11x+ with the measurement light ML traveling along an optical path OP12 different from the optical path OP11 from the fθ lens 5228. Furthermore, the measurement head 52 may receive, as returned light RL from the reference area MA11x+, a light component of light from the reference area MA11x+ generated by the measurement light ML irradiated onto the reference area MA11x+ and traveling along the optical path OP12. Furthermore, the measurement head 52 may irradiate, as returned light RL from the reference area MA11x−, with the measurement light ML traveling from the fθ lens 5228 along an optical path OP13 different from the optical path OP11 to OP12. Furthermore, the measurement head 52 may receive, as returned light RL from the reference area MA11x-, a light component of light from the reference area MA11x- generated by the measurement light ML irradiated onto the reference area MA11x+, which travels along an optical path OP13. Furthermore, the measurement head 52 may irradiate the reference area MA11y+ with measurement light ML traveling from the fθ lens 5228 along an optical path OP14 different from the optical paths OP11 to OP13. Furthermore, the measurement head 52 may receive, as returned light RL from the reference area MA11y+, a light component of light from the reference area MA11y+ generated by the measurement light ML irradiated onto the reference area MA11y+, which travels along an optical path OP14.Furthermore, the measurement head 52 may irradiate the reference area MA11y- with measurement light ML traveling along an optical path OP15 different from the optical paths OP11 to OP14 from the fθ lens 5228. Furthermore, the measurement head 52 may receive, as return light RL from the reference area MA11y-, a light component traveling along the optical path OP15 of the light from the reference area MA11y- generated by the measurement light ML irradiated onto the reference area MA11y+.

[0143] The reference region MA11c, the reference region MA11x+, the reference region MA11x-, the reference region MA11y+, and the reference region MA11y- may satisfy the following positional conditions. First, each of the reference regions MA11x+ and MA11x- may be located at a position away from the reference region MA11c along the X-axis direction (or a first direction along the reference plane FMS). Furthermore, the direction in which the reference region MA11x+ moves away from the reference region MA11c may be opposite to the direction in which the reference region MA11x- moves away from the reference region MA11c. In the examples shown in FIGS. 16 and 17, the reference region MA11x+ moves away from the reference region MA11c toward the +X side, and the reference region MA11x- moves away from the reference region MA11c toward the -X side. However, the direction in which the reference region MA11x+ moves away from the reference region MA11c may be the same as the direction in which the reference region MA11x- moves away from the reference region MA11c. Furthermore, the position of the reference region MA11x+ in the Y-axis direction (or the second direction along the reference plane FMS) may be the same as the position of the reference region MA11x- in the Y-axis direction (or the second direction along the reference plane FMS). Furthermore, each of the reference regions MA11y+ and MA11y- may be located at a position away from the reference region MA11c along the Y-axis direction (or the second direction along the reference plane FMS). Furthermore, the direction in which the reference region MA11y+ moves away from the reference region MA11c may be opposite to the direction in which the reference region MA11y- moves away from the reference region MA11c. In the examples shown in FIGS. 16 and 17, the reference region MA11y+ moves away from the reference region MA11c toward the +Y side, and the reference region MA11y- moves away from the reference region MA11c toward the -Y side. However, the direction in which the reference region MA11y+ moves away from the reference region MA11c may be the same as the direction in which the reference region MA11y- moves away from the reference region MA11c. Furthermore, the position of the reference region MA11y+ in the X-axis direction (or the first direction along the reference surface FMS) may be the same as the position of the reference region MA11y- in the X-axis direction (or the first direction along the reference surface FMS).

[0144] The control device 7 calculates a movement error E based on the measurement results of the reference area MA11c, the reference area MA11x+, the reference area MA11x-, the reference area MA11y+, and the reference area MA11y-. Z may be calculated.

[0145] For example, the control device 7 calculates the movement error E based on the measurement result of the reference area MA11c. ZZ Specifically, as described above, the movement error E Z When calculating the movement error E, the measurement device 5 measures the reference member FM both before and after the machining head 2 moves in the Z-axis direction. In this case, the control device 7 may calculate the distance from the measurement head 52 to the reference area MA11c along the Z-axis direction before the machining head 2 moves (i.e., the Z position of the reference area MA11c) from the detection result of the return light RL from the reference area MA11c before the machining head 2 moves. Furthermore, the control device 7 may calculate the distance from the measurement head 52 to the reference area MA11c along the Z-axis direction after the machining head 2 moves (i.e., the Z position of the reference area MA11c) from the detection result of the return light RL from the reference area MA11c after the machining head 2 moves. Here, the movement error E ZZ If no movement error E occurs, the difference between the Z position of the reference area MA11c before the machining head 2 moves and the Z position of the reference area MA11c after the machining head 2 moves should match the target value of the movement amount of the machining head 2 in the Z-axis direction. ZZ When this occurs, the difference between the Z position of the reference area MA11c before the machining head 2 moves and the Z position of the reference area MA11c after the machining head 2 moves does not match the target value of the movement amount of the machining head 2 in the Z axis direction. Therefore, the control device 7 calculates the difference between the Z position of the reference area MA11c before the machining head 2 moves and the Z position of the reference area MA11c after the machining head 2 moves, and determines the difference between the calculated difference and the target value of the movement amount of the machining head 2 in the Z axis direction as the movement error E ZZ It may be calculated as:

[0146] For example, the control device 7 calculates the movement error E based on the measurement results of the reference areas MA11x+ and MA11x-.BZ Specifically, the control device 7 may calculate the distance from the measurement head 52 to the reference region MA11x+ along the Z-axis direction before the movement of the machining head 2 (i.e., the Z position of the reference region MA11x+) from the detection result of the returned light RL from the reference region MA11x+ before the movement of the machining head 2. Furthermore, the control device 7 may calculate the distance from the measurement head 52 to the reference region MA11x- along the Z-axis direction before the movement of the machining head 2 (i.e., the Z position of the reference region MA11x-) from the detection result of the returned light RL from the reference region MA11x- before the movement of the machining head 2. Furthermore, the control device 7 may calculate the distance from the measurement head 52 to the reference region MA11x+ along the Z-axis direction after the movement of the machining head 2 (i.e., the Z position of the reference region MA11x+) from the detection result of the returned light RL from the reference region MA11x+ after the movement of the machining head 2. Furthermore, the control device 7 may calculate the distance from the measurement head 52 to the reference area MA11x- along the Z-axis direction after the machining head 2 has moved (i.e., the Z position of the reference area MA11x-) from the detection result of the return light RL from the reference area MA11x- after the machining head 2 has moved. Thereafter, the control device 7 may calculate the difference between the Z position of the reference area MA11x+ before the machining head 2 has moved and the Z position of the reference area MA11x- before the machining head 2 has moved as the amount of rotation (pitch rotation) of the reference member FM1 around the B axis before the machining head 2 has moved. Furthermore, the control device 7 may calculate the difference between the Z position of the reference area MA11x+ after the machining head 2 has moved and the Z position of the reference area MA11x- after the machining head 2 has moved as the amount of rotation (pitch rotation) of the reference member FM1 around the B axis after the machining head 2 has moved. Here, the movement error E BZ If no movement error E occurs, the pitch rotation amount of the reference member FM1 after the machining head 2 moves should match the pitch rotation amount of the reference member FM1 before the machining head 2 moves. BZWhen this occurs, the amount of pitch rotation of the reference member FM1 after the machining head 2 has moved does not match the amount of pitch rotation of the reference member FM1 before the machining head 2 has moved. Therefore, the difference between the amount of pitch rotation of the reference member FM1 after the machining head 2 has moved and the amount of pitch rotation of the reference member FM1 before the machining head 2 has moved is the movement error E BZ Therefore, the control device 7 calculates the difference between the pitch rotation amount of the reference member FM1 after the machining head 2 has moved and the pitch rotation amount of the reference member FM1 before the machining head 2 has moved as the movement error E BZ It may be calculated as:

[0147] For example, the control device 7 calculates the movement error E based on the measurement results of the reference areas MA11y+ and MA11y−. AZSpecifically, the control device 7 may calculate the distance from the measurement head 52 to the reference region MA11y+ along the Z-axis direction before the movement of the machining head 2 (i.e., the Z position of the reference region MA11y+) from the detection result of the returned light RL from the reference region MA11y+ before the movement of the machining head 2. Furthermore, the control device 7 may calculate the distance from the measurement head 52 to the reference region MA11y- along the Z-axis direction before the movement of the machining head 2 (i.e., the Z position of the reference region MA11y-) from the detection result of the returned light RL from the reference region MA11y- before the movement of the machining head 2. Furthermore, the control device 7 may calculate the distance from the measurement head 52 to the reference region MA11y+ along the Z-axis direction after the movement of the machining head 2 (i.e., the Z position of the reference region MA11y+) from the detection result of the returned light RL from the reference region MA11y+ after the movement of the machining head 2. Furthermore, the control device 7 may calculate the distance from the measurement head 52 to the reference area MA11y- along the Z-axis direction after the machining head 2 has moved (i.e., the Z position of the reference area MA11y-) from the detection result of the return light RL from the reference area MA11y- after the machining head 2 has moved. Thereafter, the control device 7 calculates the difference between the Z position of the reference area MA11y+ before the machining head 2 has moved and the Z position of the reference area MA11y- before the machining head 2 has moved as the amount of rotation (roll rotation amount) of the reference member FM1 around the A-axis before the machining head 2 has moved. Furthermore, the control device 7 calculates the difference between the Z position of the reference area MA11y+ after the machining head 2 has moved and the Z position of the reference area MA11y- after the machining head 2 has moved as the amount of rotation (roll rotation amount) of the reference member FM1 around the A-axis after the machining head 2 has moved. Here, the movement error E AZ If no movement error E occurs, the amount of roll rotation of the reference member FM1 after the processing head 2 moves should match the amount of roll rotation of the reference member FM1 before the processing head 2 moves. BZWhen this occurs, the amount of roll rotation of the reference member FM1 after the processing head 2 has moved does not match the amount of roll rotation of the reference member FM1 before the processing head 2 has moved. Therefore, the difference between the amount of roll rotation of the reference member FM1 after the processing head 2 has moved and the amount of roll rotation of the reference member FM1 before the processing head 2 has moved is the movement error E AZ Therefore, the control device 7 calculates the difference between the amount of roll rotation of the reference member FM1 after the machining head 2 has moved and the amount of roll rotation of the reference member FM1 before the machining head 2 has moved as the movement error E AZ It may be calculated as:

[0148] In addition, when the processing head 2 or the stage 41 moves along a movement direction different from the Z-axis direction (that is, when the movement error E Z Similarly, even when calculating a movement error other than the reference area MA11c, the control device 7 may calculate a movement error in one linear direction based on the measurement results of the reference area MA11c. The control device 7 may calculate a movement error in a rotational direction about one rotation axis based on the measurement results of the reference areas MA11x+ and MA11x-. The control device 7 may calculate a movement error in a rotational direction about another rotation axis based on the measurement results of the reference areas MA11y+ and MA11y-. However, when the machining head 2 or the stage 41 moves along the rotational direction (i.e., rotates), the difference between the position of the reference area MA11c before the machining head 2 or the stage 41 moves and the position of the reference area MA11c after the machining head 2 or the stage 41 moves includes not only a component of the movement error in the Z-axis direction but also a component of the movement amount (rotation amount) of the machining head 2 or the stage 41 along the rotational direction. Therefore, the control device 7 may calculate the movement error in one linear direction by removing the component of the movement amount (rotation amount) of the machining head 2 or the stage 41 along the rotation direction from the difference between the position of the reference area MA11c before the machining head 2 or the stage 41 moves and the position of the reference area MA11c after the machining head 2 moves. The same applies to the difference in the pitch rotation amount and the difference in the roll rotation amount.

[0149] The measurement device 5 may measure the grating pattern GP in addition to or instead of at least five reference areas MA11 in the grating pattern GP. Specifically, the measurement device 5 may measure both the reference areas MA11 and MA12 that constitute the grating pattern GP. Here, as described above, because the predetermined characteristics (e.g., height or reflectance) of the reference area MA11 are different from the predetermined characteristics of the reference area MA12, the control device 7 can identify the state of the grating pattern P on the stage 41 based on the measurement results of the reference areas MA11 and MA12 by the measurement device 5 (i.e., the detection results of the return light RL from the reference area MA11 and the return light RL from the reference area MA12). For example, the control device 7 may identify the state of the grating pattern GP before the machining head 2 moves from the detection results of the return light RL from the grating pattern GP before the machining head 2 moves. Furthermore, the control device 7 may identify the state of the grating pattern GP before the machining head 2 moves from the detection results of the return light RL from the grating pattern GP after the machining head 2 moves. Thereafter, the control device 7 calculates the movement error E based on the identified state of the grating pattern P. Z may be calculated.

[0150] For example, the movement error E XZ If no movement error E occurs, the position of the grid pattern GP in the X-axis direction after the processing head 2 has moved should match the position of the grid pattern GP in the X-axis direction before the processing head 2 has moved. XZ 18, the position of the grid pattern GP in the X-axis direction after the machining head 2 has moved does not match the position of the grid pattern GP in the X-axis direction before the machining head 2 has moved. Therefore, the difference between the position of the grid pattern GP in the X-axis direction after the machining head 2 has moved and the position of the grid pattern GP in the X-axis direction before the machining head 2 has moved is a movement error E XZ Therefore, the control device 7 calculates the difference between the position of the grid pattern GP in the X-axis direction after the machining head 2 has moved and the position of the grid pattern GP in the X-axis direction before the machining head 2 has moved as the movement error E XZ It may be calculated as:

[0151] For example, the movement error E YZ If no movement error E occurs, the position of the grid pattern GP in the Y-axis direction after the processing head 2 has moved should match the position of the grid pattern GP in the Y-axis direction before the processing head 2 has moved. YZ 18, the position of the grid pattern GP in the Y-axis direction after the machining head 2 has moved does not match the position of the grid pattern GP in the Y-axis direction before the machining head 2 has moved. Therefore, the difference between the position of the grid pattern GP in the Y-axis direction after the machining head 2 has moved and the position of the grid pattern GP in the Y-axis direction before the machining head 2 has moved is a movement error E YZ Therefore, the control device 7 calculates the difference between the position of the grid pattern GP in the Y-axis direction after the machining head 2 has moved and the position of the grid pattern GP in the Y-axis direction before the machining head 2 has moved as the movement error E YZ It may be calculated as:

[0152] For example, the movement error E CZ If no movement error E occurs, the rotation angle of the grid pattern GP in the rotation direction around the C axis after the processing head 2 has moved should match the rotation angle of the grid pattern GP in the rotation direction around the C axis before the processing head 2 has moved. CZ 19, the rotation angle of the grid pattern GP in the rotation direction around the C axis after the machining head 2 has moved does not match the rotation angle of the grid pattern GP in the rotation direction around the C axis before the machining head 2 has moved. Therefore, the difference between the rotation angle of the grid pattern GP in the rotation direction around the C axis after the machining head 2 has moved and the rotation angle of the grid pattern GP in the rotation direction around the C axis before the machining head 2 has moved is the movement error E CZ Therefore, the control device 7 calculates the difference between the rotation angle of the grid pattern GP in the rotation direction around the C axis after the processing head 2 has moved and the rotation angle of the grid pattern GP in the rotation direction around the C axis before the processing head 2 has moved as the movement error E CZ It may be calculated as:

[0153] In addition, when the processing head 2 or the stage 41 moves along a movement direction different from the Z-axis direction (that is, when the movement error E Z Similarly, even in the case where a movement error other than the above is calculated, the control device 7 may calculate the movement error in each of two different linear directions and the movement error in the rotational direction around one rotation axis based on the measurement results of the grid pattern GP. However, when the machining head 2 or the stage 41 moves along the rotational direction (i.e., rotates), the difference between the position of the grid pattern GP after the machining head 2 or the stage 41 moves and the position of the grid pattern GP before the machining head 2 or the stage 41 moves includes not only a component of the movement error in at least one of the X-axis and Y-axis directions but also a component of the movement amount (rotation amount) of the machining head 2 or the stage 41 along the rotational direction. Therefore, the control device 7 may calculate the movement error in one linear direction by removing the component of the movement amount (rotation amount) of the machining head 2 or the stage 41 along the rotational direction from the difference between the position of the grid pattern GP after the machining head 2 or the stage 41 moves and the position of the grid pattern GP before the machining head 2 moves. The same applies to the difference in the rotation angle of the grid pattern GP.

[0154] The measurement device 5 may measure the boundary BD between the reference region MA11 and the reference region MA12 in addition to or instead of at least one of the at least five reference regions MA11 and the grid pattern GP. That is, the measurement device 5 may irradiate the boundary BD with measurement light ML and receive return light RL from the boundary BD. In particular, the measurement device 5 may irradiate at least three boundaries BD, including two boundaries BD extending in different directions, with measurement light ML and receive return light RL from the at least three boundaries. For example, as shown in FIG. 20 , the measurement device 5 may irradiate the measurement light ML to a boundary BD#1 extending along the Y-axis direction and being the boundary between the reference region MA11#1 and the reference region MA12#1, which are adjacent along the X-axis direction; a boundary BD#2 extending along the X-axis direction and being the boundary between the reference region MA11#2 and the reference region MA12#2, which are adjacent along the Y-axis direction; and a boundary BD#3 extending along the Y-axis direction and being the boundary between the reference region MA11#3 and the reference region MA12#3, which are adjacent along the X-axis direction.

[0155] Alternatively, the measurement device 5 may irradiate the measurement light ML to a plurality of locations on the boundary BD between a certain reference area MA11 and a certain reference area MA12. In this case, too, the measurement device 5 may be considered to irradiate the measurement light ML to a plurality of boundaries BD. Specifically, for example, as shown in FIG. 21, the measurement device 5 may irradiate measurement light ML onto each of the boundary BD#11 (i.e., part of the boundary BD#1) between the first area portion dMA11#1-1 of the reference area MA11#1 and the first area portion dMA12#1-1 of the reference area MA12#1, the boundary BD#12 (i.e., another part of the boundary BD#1) between the second area portion dMA11#1-2 of the reference area MA11#1 and the second area portion dMA12#1-2 of the reference area MA12#1, and the boundary BD#41 (i.e., part of the boundary BD#4 extending along the X-axis direction, which is the boundary between the reference area MA11#4 and the reference area MA12#1) between the first area portion dMA11#4-1 of the reference area MA11#4 adjacent along the Y-axis direction and the third area portion dMA12#1-3 of the reference area MA12#1.

[0156] In this case, the control device 7 may calculate the position of the boundary BD (for example, the position in a three-dimensional coordinate space) based on the measurement result of the boundary BD by the measurement device 5 (i.e., the detection result of the return light RL from the boundary BD). Thereafter, the control device 7 calculates the movement error E Z For example, the control device 7 may calculate the movement error E based on the position of a first boundary BD (for example, boundary BD#1 in FIG. 20 or boundary BD#11 in FIG. 21) along at least one of the X-axis direction and the Y-axis direction, the position of a second boundary BD (for example, boundary BD#2 in FIG. 20 or boundary BD#41 in FIG. 21) along at least one of the X-axis direction and the Y-axis direction, and the position of a third boundary BD (for example, boundary BD#3 in FIG. 20 or boundary BD#12 in FIG. 21) along at least one of the X-axis direction and the Y-axis direction. XZ , movement error E YZ and movement error E CZ Because it is possible to calculate the translation amount of the plane and the rotation amount of the plane around the rotation axis intersecting the plane from the positions of three points in the plane, the movement error E can be calculated by comparing the translation amount and the rotation amount before and after the movement of at least one of the machining head 2 and the stage 41. XZ , movement error E YZ and movement error E CZ In this way, the control device 7 may calculate the movement errors in three different movement directions based on the XY positions of the three boundaries BD. Also, for example, the control device 7 may calculate the movement error E based on the position of the first boundary BD along the Z-axis direction, the position of the second boundary BD along the Z-axis direction, and the position of the third boundary BD along the Z-axis direction. ZZ , movement error E AZ and movement error E BZ This operation is essentially the same as calculating the movement error E from the positions of at least five reference areas MA11 (five reference areas MA11) described with reference to FIGS. ZZ , movement error E AZ and movement error E BZThis may be considered to be equivalent to an operation of calculating at least one of the above. In this way, the control device 7 may calculate the movement errors in three different movement directions based on the Z positions of the three boundaries BD. As a result, the control device 7 may calculate the movement errors in six different movement directions based on the X, Y, and Z positions of the three boundaries BD.

[0157] (2-2-2) Movement error calculation operation using reference member FM2 Next, the movement error calculation operation using the reference member FM2 will be described.

[0158] An example of the reference member FM2 is shown in FIG. 22. As shown in FIG. 22, the reference member FM2 is a member on which a polyhedron TP is formed on a reference surface FMS. In the example shown in FIG. 22, the reference member FM2 has a polyhedron TP corresponding to a triangular pyramid formed thereon. In this case, the polyhedron TP may include a first plane PL1, a second plane PL2, and a third plane PL3, each of which forms three side surfaces of the triangular pyramid. The first plane PL1 may have a normal line that faces in a direction different from the normal lines of the second plane PL2 and the third plane PL3. The second plane PL2 may have a normal line that faces in a direction different from the normal lines of the first plane PL1 and the third plane PL3. The third plane PL3 may have a normal line that faces in a direction different from the normal lines of the first plane PL1 and the second plane PL2. The first plane PL1 may be connected to the second plane PL2 via a first boundary line BL1 (i.e., the first side of the triangular pyramid). The second plane PL2 may be connected to the third plane PL3 via a second boundary line BL2 (i.e., the second side of the triangular pyramid). The third plane PL1 may be connected to the first plane PL1 via a third boundary line BL3 (i.e., the third side of the triangular pyramid).

[0159] The polyhedron TP is not limited to a triangular pyramid. For example, any convex polyhedron may be used as the polyhedron TP. For example, any pyramid may be used as the polyhedron TP. For example, any prism may be used as the polyhedron TP. For example, any non-convex polyhedron may be used as the polyhedron TP. When the polyhedron TP is an arbitrary convex polyhedron, there is a reduced possibility that the measurement light ML reflected and / or scattered by one surface of the polyhedron will pass through another polyhedron and then be returned to the measurement device 5 as return light RL. This has the advantage of reducing the possibility of measurement errors occurring.

[0160] As shown in FIG. 23 , the measurement device 5 may measure each of at least three planes (first plane PL1 to third plane PL3 in the example shown in FIG. 22 ) that constitute the polyhedron TP. Specifically, the measurement device 5 may irradiate each of the first plane PL1 to third plane PL3 with the measurement light ML by using the galvanometer mirror 5227 to change the irradiation position of the measurement light ML. Therefore, the first plane PL1 to third plane PL3 may be included in a scanning region that the galvanometer mirror 5227 can scan with the measurement light ML while the positional relationship between the measurement head 52 and the reference member FM is fixed. Specifically, the measurement head 52 may irradiate the first plane PL1 with the measurement light ML that travels along the optical path OP21 from the fθ lens 5228. Furthermore, the measurement head 52 may receive, as returned light RL from the first plane PL1, a light component that travels along the optical path OP21 out of the light from the first plane PL1 that is generated by the measurement light ML irradiated onto the first plane PL1. Furthermore, the measurement head 52 may irradiate the second plane PL2 with the measurement light ML traveling from the fθ lens 5228 along an optical path OP22 different from the optical path OP21. Furthermore, the measurement head 52 may receive, as returned light RL from the second plane PL2, a light component traveling along the optical path OP22 of the light from the second plane PL2 generated by the measurement light ML irradiated onto the second plane PL2. Furthermore, the measurement head 52 may irradiate the third plane PL3 with the measurement light ML traveling from the fθ lens 5228 along an optical path OP23 different from the optical path OP21 to OP22. Furthermore, the measurement head 52 may receive, as returned light RL from the third plane PL3, a light component traveling along the optical path OP23 of the light from the third plane PL3 generated by the measurement light ML irradiated onto the third plane PL3.

[0161] The measurement device 5 may irradiate each of the multiple measurement target regions on the first plane PL1 with the measurement light ML by changing the irradiation position of the measurement light ML on the first plane PL1 using the galvanometer mirror 5227. The measurement device 5 may irradiate each of the multiple measurement target regions on the second plane PL2 with the measurement light ML by changing the irradiation position of the measurement light ML on the second plane PL2 using the galvanometer mirror 5227. The measurement device 5 may irradiate each of the multiple measurement target regions on the third plane PL3 with the measurement light ML by changing the irradiation position of the measurement light ML on the third plane PL3 using the galvanometer mirror 5227.

[0162] The control device 7 calculates the movement error E based on the measurement results of at least three planes (first plane PL1 to third plane PL3 in the example shown in FIG. 22) that constitute the polyhedron TP. Z Hereinafter, the movement error E may be calculated based on the measurement results of the first plane PL1 to the third plane PL3. Z An example of the operation for calculating the following will be described.

[0163] Specifically, the control device 7 may calculate the position (specifically, the three-dimensional position) of the first plane PL1 from the detection result of the return light RL from the first plane PL1. To calculate the position of the first plane PL1, the measurement device 5 may use the galvanometer mirror 5227 to change the irradiation position of the measurement light ML on the first plane PL1, thereby irradiating the measurement light ML onto each of at least three measurement target regions on the first plane PL1. However, the measurement device 5 does not need to irradiate the measurement light ML onto the first boundary line BL1 between the first plane PL1 and the second plane PL2 and the third boundary line BL3 between the first plane PL1 and the third plane PL3. In this case, the control device 7 may calculate the positions of the at least three measurement target regions based on the measurement results of the at least three measurement target regions, and may calculate the position of the first plane PL1 by specifying the plane connecting the three measurement target regions located at the calculated positions as the first plane PL1.

[0164] Furthermore, the control device 7 may calculate the position (specifically, the three-dimensional position) of the second plane PL2 from the detection result of the return light RL from the second plane PL2. To calculate the position of the second plane PL2, the measurement device 5 may use the galvanometer mirror 5227 to change the irradiation position of the measurement light ML on the second plane PL2, thereby irradiating the measurement light ML onto each of at least three measurement target regions on the second plane PL2. However, the measurement device 5 does not need to irradiate the measurement light ML onto the first boundary line BL1 between the second plane PL2 and the first plane PL1 and the second boundary line BL2 between the second plane PL2 and the third plane PL3. In this case, the control device 7 may calculate the positions of the at least three measurement target regions based on the measurement results of the at least three measurement target regions, and may calculate the position of the second plane PL2 by specifying the plane connecting the three measurement target regions located at the calculated positions as the second plane PL2.

[0165] Furthermore, the control device 7 may calculate the position (specifically, the three-dimensional position) of the third plane PL3 from the detection result of the return light RL from the third plane PL3. To calculate the position of the third plane PL3, the measurement device 5 may use the galvanometer mirror 5227 to change the irradiation position of the measurement light ML on the third plane PL3, thereby irradiating the measurement light ML onto each of at least three measurement target regions on the third plane PL3. However, the measurement device 5 does not need to irradiate the measurement light ML onto the third boundary line BL3 between the third plane PL3 and the first plane PL1 and the second boundary line BL2 between the third plane PL3 and the second plane PL2. In this case, the control device 7 may calculate the positions of the at least three measurement target regions based on the measurement results of the at least three measurement target regions, and may calculate the position of the third plane PL3 by identifying the plane connecting the three measurement target regions located at the calculated positions as the third plane PL3.

[0166] Thereafter, the control device 7 may calculate the positions of the vertices VP of the polyhedron TP based on the calculated positions of the first plane PL1 to the third plane PL3. An example of the vertices VP of the polyhedron TP is shown in FIG. 24. As shown in FIG. 24, the points at which the first boundary line BL1 to the third boundary line BL3 intersect may be used as the vertices VP. The points at which the first boundary line BL1 and the third plane PL3 intersect may be used as the vertices VP. The points at which the second boundary line BL2 and the first plane PL1 intersect may be used as the vertices VP. The points at which the third boundary line BL3 and the second plane PL2 intersect may be used as the vertices VP.

[0167] Furthermore, the control device 7 may calculate the position of the central axis CX of the polyhedron TP based on the calculated positions of the first plane PL1 to the third plane PL3. An example of the central axis CX of the polyhedron TP is shown in FIG. 24. As shown in FIG. 24, an axis connecting the incenter IC of the fourth plane (polygon) PL4, which is obtained by connecting points BP1 to BP3 located equidistant from the vertex VP on the first boundary line BL1 to the third boundary line BL3, and the vertex VP may be used as the central axis CX. In this case, the control device 7 may calculate the position of the fourth plane PL4 based on the calculated positions of the first plane PL1 to the third plane PL3, calculate the position of the incenter IC based on the calculated position of the fourth plane PL4, and calculate the position of the axis connecting the calculated position of the incenter IC and the calculated position of the vertex VP as the position of the central axis CX.

[0168] The control device 7 performs the same operation both before and after the machining head 2 moves along the Z-axis direction. As a result, the control device 7 calculates the positions of the vertex VP and the central axis CX before the machining head 2 moves, and the positions of the vertex VP and the central axis CX after the machining head 2 moves. Thereafter, the control device 7 calculates a movement error E based on at least one of the positions of the vertex VP and the central axis CX. Z may be calculated.

[0169] For example, the control device 7 calculates the movement error E based on the position of the vertex VP in the Z-axis direction (Z position). ZZSpecifically, the movement error E ZZ If no movement error E occurs, the difference between the Z position of the vertex VP before the machining head 2 moves and the Z position of the vertex VP after the machining head 2 moves should match the target value of the movement amount of the machining head 2 in the Z-axis direction. ZZ When this occurs, the difference between the Z position of the vertex VP before the machining head 2 moves and the Z position of the vertex VP after the machining head 2 moves does not match the target value of the movement amount of the machining head 2 in the Z axis direction. Therefore, the control device 7 calculates the difference between the Z position of the vertex VP before the machining head 2 moves and the Z position of the vertex VP after the machining head 2 moves, and determines the difference between the calculated difference and the target value of the movement amount of the machining head 2 in the Z axis direction as the movement error E ZZ It may be calculated as:

[0170] For example, the control device 7 calculates the movement error E based on the position of the vertex VP in the X-axis direction (X position). XZ Specifically, the movement error E XZ If no movement error E occurs, the X position of the vertex VP after the machining head 2 has moved should match the X position of the vertex VP before the machining head 2 has moved. XZ When this occurs, the X position of the vertex VP after the machining head 2 has moved does not match the X position of the vertex VP before the machining head 2 has moved. Therefore, the difference between the X position of the vertex VP after the machining head 2 has moved and the X position of the vertex VP before the machining head 2 has moved is the movement error E XZ Therefore, the control device 7 calculates the difference between the X position of the vertex VP after the machining head 2 has moved and the X position of the vertex VP before the machining head 2 has moved as the movement error E XZ It may be calculated as:

[0171] For example, the control device 7 calculates the movement error E based on the position of the vertex VP in the Y-axis direction (Y position). YZ Specifically, the movement error E YZIf no movement error E occurs, the Y position of the vertex VP after the machining head 2 has moved should match the Y position of the vertex VP before the machining head 2 has moved. YZ When this occurs, the Y position of the vertex VP after the machining head 2 has moved does not match the Y position of the vertex VP before the machining head 2 has moved. Therefore, the difference between the Y position of the vertex VP after the machining head 2 has moved and the Y position of the vertex VP before the machining head 2 has moved is the movement error E YZ Therefore, the control device 7 calculates the difference between the Y position of the vertex VP after the machining head 2 has moved and the Y position of the vertex VP before the machining head 2 has moved as the movement error E YZ It may be calculated as:

[0172] For example, the control device 7 calculates the movement error E based on the rotation angle of the central axis CX around the A axis. AZ Specifically, the movement error E AZ If no movement error E occurs, the rotation angle of the central axis CX around the A axis after the machining head 2 has moved (in other words, the tilt angle) should match the rotation angle of the central axis CX around the A axis before the machining head 2 has moved. AZ When this occurs, the rotation angle of the central axis CX around the A axis after the machining head 2 has moved does not match the rotation angle of the central axis CX around the A axis before the machining head 2 moved. Therefore, the difference between the rotation angle of the central axis CX around the A axis after the machining head 2 has moved and the rotation angle of the central axis CX around the A axis before the machining head 2 moved is the movement error E AZ Therefore, the control device 7 calculates the rotation angle of the central axis CX around the A-axis after the machining head 2 has moved, based on the position of the central axis CX after the machining head 2 has moved, calculates the rotation angle of the central axis CX around the A-axis before the machining head 2 has moved, based on the position of the central axis CX before the machining head 2 has moved, and calculates the difference between the rotation angle of the central axis CX around the A-axis after the machining head 2 has moved and the rotation angle of the central axis CX around the A-axis before the machining head 2 has moved as the movement error E AZ It may be calculated as:

[0173] For example, the control device 7 calculates the movement error E based on the rotation angle of the central axis CX around the B axis. BZ Specifically, the movement error E BZ If no movement error E occurs, the rotation angle of the central axis CX around the B axis after the machining head 2 has moved should match the rotation angle of the central axis CX around the B axis before the machining head 2 moved. BZ When this occurs, the rotation angle of the central axis CX around the B axis after the machining head 2 has moved does not match the rotation angle of the central axis CX around the B axis before the machining head 2 has moved. Therefore, the difference between the rotation angle of the central axis CX around the B axis after the machining head 2 has moved and the rotation angle of the central axis CX around the B axis before the machining head 2 has moved is the movement error E BZ Therefore, the control device 7 calculates the rotation angle of the central axis CX around the B axis after the machining head 2 has moved, based on the position of the central axis CX after the machining head 2 has moved, calculates the rotation angle of the central axis CX around the B axis before the machining head 2 has moved, based on the position of the central axis CX before the machining head 2 has moved, and calculates the difference between the rotation angle of the central axis CX around the B axis after the machining head 2 has moved and the rotation angle of the central axis CX around the B axis before the machining head 2 has moved as the movement error E BZ It may be calculated as:

[0174] For example, the control device 7 calculates the movement error E based on the rotation angle around the C axis of the fourth plane PL4 used to calculate the central axis CX. CZ Specifically, the movement error E CZ If no movement error E occurs, the rotation angle of the fourth plane PL4 around the C axis after the machining head 2 has moved should match the rotation angle of the fourth plane PL4 around the C axis before the machining head 2 has moved. CZ When this occurs, the rotation angle of the fourth plane PL4 about the C axis after the machining head 2 has moved does not match the rotation angle of the fourth plane PL4 about the C axis before the machining head 2 has moved. Therefore, the difference between the rotation angle of the fourth plane PL4 about the C axis after the machining head 2 has moved and the rotation angle of the fourth plane PL4 about the C axis before the machining head 2 has moved is the movement error E CZTherefore, the control device 7 calculates the rotation angle of the fourth plane PL4 around the C-axis after the machining head 2 has moved, based on the positions of the first plane PL1 to the third plane PL3 after the machining head 2 has moved, calculates the rotation angle of the fourth plane PL4 around the C-axis before the machining head 2 has moved, based on the positions of the first plane PL1 to the third plane PL3 before the machining head 2 has moved, and calculates the difference between the rotation angle of the fourth plane PL4 around the C-axis after the machining head 2 has moved and the rotation angle of the fourth plane PL4 around the C-axis before the machining head 2 has moved as the movement error E CZ It may be calculated as:

[0175] In addition, when the processing head 2 or the stage 41 moves along a movement direction different from the Z-axis direction (that is, when the movement error E Z Similarly, even in the case of calculating movement errors other than the above, the control device 7 may calculate the movement errors in each of three different linear directions and the orthogonality of the three different linear directions based on the position of the vertex VP of the polyhedron TP. The control device 7 may calculate the movement errors in each of two rotational directions around two different rotational axes based on the position of the central axis CX of the polyhedron TP. The control device 7 may calculate the movement error in the rotational direction around one rotational axis based on the position of the fourth plane PL4. However, when the machining head 2 or the stage 41 moves along the rotational direction (i.e., rotates), the difference between the position of the vertex VP after the machining head 2 or the stage 41 moves and the position of the vertex VP before the machining head 2 or the stage 41 moves includes not only a component of movement error in at least one of the X-axis, Y-axis, and Z-axis directions, but also a component of the movement amount (rotation amount) of the machining head 2 or the stage 41 along the rotational direction. Therefore, the control device 7 may calculate the linear movement error by removing the component of the movement amount (rotation amount) of the machining head 2 or stage 41 along the rotation direction from the difference between the position of the vertex VP after the machining head 2 or stage 41 has moved and the position of the vertex VP before the machining head 2 or stage 41 has moved. The same applies to the difference in the rotation angle of the central axis CX and the difference in the rotation angle of the fourth plane PL4.

[0176] Furthermore, the measurement device 5 may measure the first boundary line BL1 between the second plane PL2 and the first plane PL1, the second boundary line BL2 between the second plane PL2 and the third plane PL3, and the third boundary line BL3 between the third plane PL3 and the first plane PL1 by irradiating measurement light ML onto these first boundary line BL1, second boundary line BL2, and third boundary line BL3.

[0177] (2-2-3) Movement error calculation operation using reference member FM3 Next, the movement error calculation operation using the reference member FM3 will be described.

[0178] An example of the reference member FM3 is shown in Fig. 25. As shown in Fig. 25, the reference member FM3 is a member in which at least one reflector RM1 and at least one reflector RM2 are arranged on a reference plane FMS. In the example shown in Fig. 25, the reference member FM3 includes three reflectors RM1 (specifically, reflectors RM1#1 to RM1#3) and three reflectors RM2 (specifically, reflectors RM2#1 to RM2#3). However, the number of reflectors RM1 and the number of reflectors RM2 are not limited to three.

[0179] The three reflectors RM1 may include at least two reflectors RM1 whose positions differ from one another in one direction (e.g., the X-axis direction) along the reference plane FMS. In the example shown in FIG. 25, the position of the reflector RM1#1 in the X-axis direction, the position of the reflector RM1#2 in the X-axis direction, and the position of the reflector RM1#3 in the X-axis direction are all different from one another. The three reflectors RM1 may also include at least two reflectors RM1 whose positions differ from one another in another direction (e.g., the Y-axis direction) along the reference plane FMS. In the example shown in FIG. 25, the position of the reflector RM1#1 in the Y-axis direction is all different from one another, and the position of the reflector RM1#2 in the Y-axis direction and the position of the reflector RM1#3 in the Y-axis direction are all different from one another. The three reflectors RM1 may also be arranged on a circle. In particular, the three reflectors RM1 may be arranged at equal intervals on the circle. In the following description, it is assumed that the three reflectors RM1 are arranged at intervals of 120 degrees on the circle. However, the location of the reflector RM1 is not limited to the location shown in FIG.

[0180] The three reflectors RM2 may include at least two reflectors RM2 whose positions differ from one another in one direction (e.g., the X-axis direction) along the reference plane FMS. In the example shown in FIG. 25, the position of the reflector RM2#1 in the X-axis direction, the position of the reflector RM2#2 in the X-axis direction, and the position of the reflector RM2#3 in the X-axis direction are all different from one another. The three reflectors RM2 may also include at least two reflectors RM2 whose positions differ from one another in another direction (e.g., the Y-axis direction) along the reference plane FMS. In the example shown in FIG. 25, the position of the reflector RM2#3 in the Y-axis direction is all different from the position of the reflector RM2#1 in the Y-axis direction and the position of the reflector RM2#2 in the Y-axis direction. The three reflectors RM2 may also be arranged circumferentially. The three reflectors RM2 may also be arranged on the same circumference as the circumference on which the three reflectors RM1 are arranged. In particular, the three reflectors RM1 may be arranged at equal intervals on the circumference. In the following description, the three reflectors RM2 are assumed to be arranged at intervals of 120 degrees on the same circumference as the three reflectors RM1, but the arrangement positions of the reflectors RM2 are not limited to the positions shown in FIG.

[0181] The reflector RM1 is an optical system that reflects at least a portion of the measurement light ML that has entered the reflector RM1 as return light RL toward the measurement head 52. The reflector RM2 is also an optical system that reflects at least a portion of the measurement light ML that has entered the reflector RM2 toward the measurement head 52 as return light RL.

[0182] An example of the structure of reflector RM1 is shown in FIG. 26. As shown in FIG. 26, reflector RM1 may include a reflecting member 911 and a reflecting member 912. The reflecting member 911 is an optical element that reflects the measurement light ML incident on reflector RM1 toward the reflecting member 912. The reflecting member 912 is an optical element that reflects the measurement light ML from the reflecting member 911 toward the reflecting member 911. The measurement light ML reflected by the reflecting member 912 is incident on the reflecting member 911 as returned light RL. The reflecting member 911 reflects the returned light RL incident on the reflecting member 911 toward the measurement head 52. The reflecting members 911 and 912 may be aligned with each other so that the optical path of the measurement light ML and the optical path of the returned light RL coincide with each other. In the example shown in FIG. 26, a double-pass corner cube (a type of retroreflecting mirror) in which two mirrors are combined to form a 90-degree angle is used as the reflecting member 911.

[0183] When such a reflector RM1 is used, the control device 7 can calculate the distance between the measurement head 52 and the reflector RM1 in the direction along the optical path of the measurement light ML, based on the measurement results of the reflector RM1 by the measurement device 5. In other words, the control device 7 can calculate the position of the reflector RM1 in the direction along the optical path of the measurement light ML.

[0184] Next, an example of the structure of reflector RM2 is shown in FIG. 27. As shown in FIG. 27, reflector RM2 may include a reflecting member 921 and a reflecting member 922. The reflecting members 921 and 922 may be the same as the above-described reflecting members 911 and 912, respectively. Reflector RM2 further includes an optical path length adjustment element 923. The measurement light ML incident on reflector RM2 is incident on the optical path length adjustment element 923. The measurement light ML incident on the optical path length adjustment element 913 passes through the optical path length adjustment element 923 and is incident on the reflecting member 921. In this case, in reflector RM2, as in reflector RM1, the reflecting member 911 reflects the measurement light ML toward the reflecting member 912, and the reflecting member 912 reflects the measurement light ML as returned light RL toward the reflecting member 911. The reflecting member 911 reflects the returned light RL toward the optical path length adjustment element 923. The return light RL that has entered the optical path length adjustment element 923 passes through the optical path length adjustment element 923 and is emitted from the reflector RM2 toward the measurement head 52.

[0185] The optical path length adjustment element 923 has the property of being able to change the optical path lengths (in other words, optical distances) of the measurement light ML and the return light RL according to differences in the incident position of the measurement light ML. In particular, the optical path length adjustment element 923 may have the property of being able to change the optical path lengths of the measurement light ML and the return light RL according to differences in the incident position of the measurement light ML in a direction intersecting the optical path of the measurement light ML incident on the reference member FM3 (in the example shown in FIG. 27, the direction along the XY plane).

[0186] 27, an optical element is used as the optical path length adjustment element 923, whose thickness in a direction along the optical path of the measurement light ML incident on the reference member FM3 (in the example shown in FIG. 27, the Z-axis direction) changes stepwise along a direction intersecting the optical path of the measurement light ML incident on the reference member FM3. In this case, as shown in FIG. 27, the optical path length adjustment element 923 may be considered to be an optical element in which a plurality of element portions 9231 having different thicknesses are arranged along a direction intersecting the optical path of the measurement light ML. In this case, the measurement light ML incident on one incident position on the incident surface of the reflector RM is incident on one element portion 9231 (e.g., element portion 9231#1), and the measurement light ML incident on another incident position on the incident surface of the reflector RM different from the one incident position is incident on another element portion 9231 different from the one element portion 9231 (e.g., element portion 9231#2). Here, because the thicknesses of the element portions 9231 are different, the optical path length of the measurement light ML and the return light RL passing through one element portion 9231 is different from the optical path length of the measurement light ML and the return light RL passing through another element portion 9231 that is different from the one element portion 9231. Specifically, the optical path length of the measurement light ML and the return light RL from one incident position to the position where the return light RL is emitted from the reflector RM2 via one element portion 9231 and the reflecting members 921 and 922 (that is, from one incident position to one emission position) is different from the optical path length of the measurement light ML and the return light RL from another incident position to the position where the return light RL is emitted from the reflector RM2 via the other element portion 9231 and the reflecting members 921 and 922 (that is, from another incident position to another emission position).

[0187] 27 , the measurement head 52 may irradiate the measurement light ML traveling from the fθ lens 5228 along the optical path OP31 onto the reflecting member 921 via one element portion 9231 (e.g., element portion 9231#1). Furthermore, the measurement head 52 may receive, as the return light RL from the reflecting members 921 and 922, a light component traveling along the optical path OP31 via one element portion 9231 (e.g., element portion 9231#1). For example, the measurement head 52 may irradiate the measurement light ML traveling from the fθ lens 5228 along the optical path OP32 onto the reflecting member 921 via another element portion 9231 (e.g., element portion 9231#2). Furthermore, the measurement head 52 may receive light components of the light from the reflecting members 921 and 922 that travel along the optical path OP32 through other element parts 9231 (e.g., element part 9231#2) as return light RL from the reflecting members 921 and 922.

[0188] When such a reflector RM2 is used, the control device 7 can calculate the position of the reflector RM2 in the direction intersecting the optical path of the measurement light ML based on the measurement result of the reflector RM2 by the measurement device 5. This is because, when the position of the reflector RM2 in the direction intersecting the optical path of the measurement light ML (e.g., its position relative to the measurement head 52) changes, the incident position of the measurement light ML on the optical path length adjustment element 923 changes. When the incident position of the measurement light ML on the optical path length adjustment element 923 changes, the optical path lengths of the measurement light ML and the return light RL change. When the optical path lengths of the measurement light ML and the return light RL change, the timing at which pulsed light appears in the interference light detected by the detector 5226 changes. Therefore, the detection result of the interference light by the detector 5226 contains information about the position of the reflector RM2 in the direction intersecting the optical path of the measurement light ML. Therefore, the distance from the measurement head 52 to the reflector RM2 calculated by the control device 7 varies depending on the position of the reflector RM2 in the direction intersecting the optical path of the measurement light ML. That is, the control device 7 can calculate the distance from the measurement head 52 to the reflector RM2, which varies depending on the position of the reflector RM2 in a direction intersecting the optical path of the measurement light ML. In particular, the control device 7 can calculate the distance from the measurement head 52 to the reflector RM2, which varies depending on the position of the reflector RM2 in the optical path length changing direction of the optical path length adjustment element 923. The optical path length changing direction is a direction that satisfies the condition that "the optical path length changes when the incident position of the measurement light ML changes along the optical path length changing direction." In the example shown in Fig. 27, the thickness of the optical path length adjustment element 923 changes stepwise depending on the position of the optical path length changing element 923 in the X-axis direction, and therefore the optical path length changing direction may be considered to be the X-axis direction.

[0189] In this embodiment, the three reflectors RM2 may be arranged so that the optical path length changing directions are different from one another. In Fig. 25, the optical path length changing directions of the three reflectors RM2 are indicated by arrows. In the example shown in Fig. 25, the three reflectors RM2 are arranged so that the optical path length changing directions are offset by 120°. However, at least two of the three reflectors RM2 may be arranged so that the optical path length changing directions are the same.

[0190] The control device 7 calculates the movement error E based on the measurement results of the three reflectors RM1 and the measurement results of the three reflectors RM2. Z For example, the control device 7 may calculate the movement error E based on the measurement results of the three reflectors RM1. ZZ , movement error E AZ and movement error E BZ For example, the control device 7 may calculate at least one of the following based on the measurement results of the three reflectors RM2: XZ , movement error E XZ and movement error E CZ At least one of the following may be calculated.

[0191] Movement error E ZZ , movement error E AZ and movement error E BZ In order to calculate at least one of the above, the control device 7 may calculate the distances between the measurement head 52 and the three reflectors RM1 in the direction along the Z axis (i.e., the Z positions of the three reflectors RM1) from the detection results of the return light RL from the three reflectors RM1. Note that, hereinafter, the distances between the measurement head 52 and the reflectors RM1#1, RM1#2, and RM1#3 are represented using the symbols Dz1, Dz2, and Dz3, respectively.

[0192] Thereafter, the control device 7 may calculate a position Dz0 of the reference member FM3 in the Z-axis direction, a rotation angle (amount of rotation) θa of the reference member FM3 in the rotation direction about the A-axis, and a rotation angle (amount of rotation) θb of the reference member FM3 in the rotation direction about the B-axis, based on the Z positions of the three reflectors RM1 (i.e., distances Dz1, Dz2, and Dz3). For example, the control device 7 may calculate an average value Dzav (e.g., (Dz1+Dz2+Dz3) / 3) of the Z positions of the three reflectors RM1 as the position Dz0 of the reference member FM3. Alternatively, the control device 7 may calculate an average value (e.g., (Dz1+Dz2+Dz3+Dz4+Dz5+Dz6) / 6) of the Z positions of the three reflectors RM1 and the positions of the three reflectors RM1 (distances Dz4, Dz5, and Dz6 calculated from measurement results of three reflectors RM2, which will be described later) as the average value Dzav. For example, the control device 7 may calculate the rotation angle θa using Equation 1, "θa=arcsin((ΔDz1-ΔDz2+ΔDz3) / 2r)". For example, the control device 7 may calculate the rotation angle θb using Equation 2, "θb=arcsin((ΔDz2 / cos30°-ΔDz3 / cos30°) / 2r)". Note that "ΔDz1" in Equation 1 is calculated from the equation "ΔDz1=Dz1-Dzav". "ΔDz2" in Equations 1 and 2 is calculated from the equation "ΔDz2=Dz2-Dzav". "ΔDz3" in Equations 1 and 2 is calculated from the equation "ΔDz3=Dz3-Dzav". "r" in Equations 1 and 2 is the radius of the circumference on which the three reflectors RM1 are arranged.

[0193] The control device 7 performs the same operation both before and after the machining head 2 moves along the Z-axis direction. As a result, the control device 7 calculates the position Dz0, rotation angle θa, and rotation angle θb of the reference member FM3 before the machining head 2 moves, and the position Dz0, rotation angle θa, and rotation angle θb of the reference member FM3 after the machining head 2 moves. Thereafter, the control device 7 calculates the movement error E based on at least one of the position Dz0, rotation angle θa, and rotation angle θb. Z may be calculated.

[0194] For example, the control device 7 calculates the movement error E based on the position Dz0 of the reference member FM3. ZZ Specifically, the movement error E ZZ If no movement error E occurs, the difference between the position Dz0 of the reference member FM3 before the machining head 2 moves and the position Dz0 of the reference member FM3 after the machining head 2 moves should match the target value of the movement amount of the machining head 2 in the Z-axis direction. ZZ When this occurs, the difference between the position Dz0 of the reference member FM3 before the machining head 2 moves and the position Dz0 of the reference member FM3 after the machining head 2 moves does not match the target value of the movement amount of the machining head 2 in the Z-axis direction. Therefore, the control device 7 calculates the difference between the position Dz0 of the reference member FM3 before the machining head 2 moves and the position Dz0 of the reference member FM3 after the machining head 2 moves, and determines the difference between the calculated difference and the target value of the movement amount of the machining head 2 in the Z-axis direction as the movement error E ZZ It may be calculated as:

[0195] For example, the control device 7 calculates the movement error E based on the rotation angle θa of the reference member FM3. AZ Specifically, the movement error E AZ If no movement error E occurs, the rotation angle θa of the reference member FM3 after the machining head 2 has moved should match the rotation angle θa of the reference member FM3 before the machining head 2 has moved. AZ When this occurs, the rotation angle θa of the reference member FM3 after the machining head 2 has moved does not match the rotation angle θa of the reference member FM3 before the machining head 2 has moved. Therefore, the difference between the rotation angle θa after the machining head 2 has moved and the rotation angle θa before the machining head 2 has moved is the movement error E AZ Therefore, the control device 7 calculates the difference between the rotation angle θa after the machining head 2 has moved and the rotation angle θa before the machining head 2 has moved as the movement error E AZ It may be calculated as:

[0196] For example, the control device 7 calculates the movement error E based on the rotation angle θb of the reference member FM3.BZ Specifically, the movement error E BZ If no movement error E occurs, the rotation angle θb of the reference member FM3 after the machining head 2 has moved should match the rotation angle θb of the reference member FM3 before the machining head 2 has moved. BZ When this occurs, the rotation angle θb of the reference member FM3 after the machining head 2 has moved does not match the rotation angle θb of the reference member FM3 before the machining head 2 has moved. Therefore, the difference between the rotation angle θb after the machining head 2 has moved and the rotation angle θb before the machining head 2 has moved is the movement error E BZ Therefore, the control device 7 calculates the difference between the rotation angle θb after the machining head 2 has moved and the rotation angle θb before the machining head 2 has moved as the movement error E BZ It may be calculated as:

[0197] Movement error E XZ , movement error E YZ and movement error E CZ In order to calculate at least one of the above, the control device 7 may calculate the distance between the measurement head 52 and the reflector RM2, which varies depending on the position of the reflector RM2 in a direction intersecting the optical path of the measurement light ML (particularly, the optical path length changing direction), from the detection results of the return light RL from the three reflectors RM2. Note that, hereinafter, the distances to the reflectors RM2#1, RM2#2, and RM2#3 will be represented using the symbols Dz4, Dz5, and Dz6, respectively.

[0198] Thereafter, the control device 7 may calculate the position Dx0 of the reference member FM3 in the X-axis direction, the position Dy0 of the reference member FM3 in the Y-axis direction, and the rotation angle (amount of rotation) θc of the reference member FM3 in the rotation direction about the C-axis, based on the distances between the measurement head 52 and the three reflectors RM2 (i.e., distances Dz4, Dz5, and Dz6). For example, the control device 7 may calculate the position Dx0 (actually, the amount of displacement in the X-axis direction) using Equation 3, "Dx0=((Dz4+Dz5-DZ6) / 2". For example, the control device 7 may calculate the position Dy0 (actually, the amount of displacement in the Y-axis direction) using Equation 4, "Dy0=((Dz4 / cos30°-Dz5 / cos30°) / 2". For example, the control device 7 may calculate the rotation angle θc using Equation 5, "θc=arcsin(((ΔDz4+ΔDz5+ΔDz6) / 3) / r)".

[0199] The control device 7 performs the same operation both before and after the machining head 2 moves along the Z-axis direction. As a result, the control device 7 calculates the position Dx0, position Dy0, and rotation angle θc of the reference member FM3 before the machining head 2 moves, and the position Dx0, position Dy0, and rotation angle θc of the reference member FM3 after the machining head 2 moves. Thereafter, the control device 7 calculates the movement error E based on at least one of the position Dx0, position Dy0, and rotation angle θc. Z may be calculated.

[0200] For example, the control device 7 calculates the movement error E based on the position Dx0 of the reference member FM3. XZ Specifically, the movement error E XZ If no movement error E occurs, the position Dx0 of the reference member FM3 after the machining head 2 has moved should match the position Dx0 of the reference member FM3 before the machining head 2 has moved. XZWhen this occurs, the position Dx0 of the reference member FM3 after the machining head 2 has moved does not match the position Dx0 of the reference member FM3 before the machining head 2 has moved. Therefore, the difference between the position Dx0 after the machining head 2 has moved and the position Dx0 before the machining head 2 has moved is the movement error E XZ Therefore, the control device 7 calculates the difference between the position Dx0 after the machining head 2 has moved and the position Dx0 before the machining head 2 has moved as the movement error E XZ It may be calculated as:

[0201] For example, the control device 7 calculates the movement error E based on the position Dy0 of the reference member FM3. YZ Specifically, the movement error E YZ If no movement error E occurs, the position Dy0 of the reference member FM3 after the machining head 2 has moved should match the position Dy0 of the reference member FM3 before the machining head 2 has moved. YZ When this occurs, the position Dy0 of the reference member FM3 after the machining head 2 has moved does not match the position Dy0 of the reference member FM3 before the machining head 2 has moved. Therefore, the difference between the position Dy0 after the machining head 2 has moved and the position Dy0 before the machining head 2 has moved is the movement error E YZ Therefore, the control device 7 calculates the difference between the position Dy0 after the machining head 2 has moved and the position Dy0 before the machining head 2 has moved as the movement error E YZ It may be calculated as:

[0202] For example, the control device 7 calculates the movement error E based on the rotation angle θc of the reference member FM3. CZ Specifically, the movement error E CZ If no movement error E occurs, the rotation angle θc of the reference member FM3 after the machining head 2 has moved should match the rotation angle θc of the reference member FM3 before the machining head 2 has moved. CZWhen this occurs, the rotation angle θc of the reference member FM3 after the machining head 2 has moved does not match the rotation angle θc of the reference member FM3 before the machining head 2 has moved. Therefore, the difference between the rotation angle θc after the machining head 2 has moved and the rotation angle θc before the machining head 2 has moved is the movement error E CZ Therefore, the control device 7 calculates the difference between the rotation angle θc after the machining head 2 has moved and the rotation angle θc before the machining head 2 has moved as the movement error E CZ It may be calculated as:

[0203] In addition, when the processing head 2 or the stage 41 moves along a movement direction different from the Z-axis direction (that is, when the movement error E Z Similarly, even in the case where a movement error other than the above is calculated, the control device 7 may calculate the movement error in each of two different linear directions and the movement error in the rotational direction about one rotation axis based on the measurement results of the three reflectors RM1. The control device 7 may calculate the movement error in one linear direction and the movement error in the rotational direction about two different rotation axes based on the measurement results of the three reflectors RM2. However, when the machining head 2 or the stage 41 moves along the rotational direction (i.e., rotates), the difference between the position Dz0 after the machining head 2 or the stage 41 has moved and the position Dz0 before the machining head 2 or the stage 41 has moved includes not only a component of the movement error in the Z-axis direction but also a component of the movement amount (rotation amount) of the machining head 2 or the stage 41 along the rotational direction. Therefore, the control device 7 may calculate the movement error in one linear direction by removing the component of the movement amount (rotation amount) of the machining head 2 or stage 41 along the rotation direction from the difference between the position Dz0 after the machining head 2 or stage 41 has moved and the position Dz before the machining head 2 or stage 41 has moved. The same applies to the differences between the position Dx0, the position Dy0, the rotation angle θa, the rotation angle θb, and the rotation angle θc.

[0204] 27 。 For example, as shown in FIG. 28 , the reflector RM2 may include an optical path length adjustment element 924 instead of the optical path length adjustment element 923. The optical path length adjustment element 924 is an optical member in which a plurality of optical elements 9241, each having a different refractive index compared to the optical path length adjustment element 924, are stacked along a direction intersecting the optical path of the measurement light ML. The thicknesses of the plurality of optical elements 9241 (specifically, the size in the direction along the optical path of the measurement light ML) may be the same. Even in this case, the optical path lengths of the measurement light ML and the returned light RL change due to the difference in the refractive index of the optical elements 9241 onto which the measurement light ML is incident. Alternatively, as shown in FIG. 29 , the reflector RM2 may include a reflecting member 925 instead of the optical path length adjustment element 923 and the reflecting member 922. The reflecting member 925 may differ from the reflecting member 922 in that the position of the reflecting surface that reflects the measurement light ML changes along a direction intersecting the irradiation direction of the measurement light ML. Even in this case, the optical path lengths of the measurement light ML and the returned light RL change due to differences in the position of the reflecting surface onto which the measurement light ML is incident. Alternatively, for example, as shown in FIG. 30 , the reflector RM2 may include multiple reflecting members 926 instead of the optical path length adjustment element 923. Each reflecting member 926 includes reflecting members 921 and 922. The multiple reflecting members 926 are aligned along a direction intersecting the optical path of the measurement light ML. The multiple reflecting members 926 are disposed at different positions along the optical path of the measurement light ML. Even in this case, the optical path lengths of the measurement light ML and the returned light RL change due to differences in the position of the reflecting member 926 onto which the measurement light ML is incident (the position along the optical path of the measurement light ML).

[0205] (3) Technical effect of machine tool 1 As described above, in this embodiment, the control device 7 can calculate movement errors that occur in the movement of at least one of the machining head 2 and the stage 41 based on the measurement results of the reference member FM. In particular, the control device 7 can calculate movement errors in multiple movement directions that occur in the movement of at least one of the machining head 2 and the stage 41 based on the measurement results of a single reference member FM by a single measuring device 5. Therefore, compared to the machine tool of the comparative example, which needs to measure multiple reference members and / or needs to measure the reference member using multiple measuring devices to calculate movement errors in multiple movement directions, the time required to calculate movement errors in multiple movement directions can be shortened. Furthermore, the effort required to calculate movement errors in multiple movement directions can also be reduced.

[0206] The control device 7 may calibrate an attachment error of the measuring head 52 to the processing head 2. In at least one of the first to seventh modified examples described below, the control device 7 may also calibrate an attachment error of the measuring head 52 to the processing head 2.

[0207] For example, a reference member for calibrating an attachment error of the measurement head 52 to the processing head 2 may be placed on the stage 41, and the control device 7 may calculate in advance the position and orientation of the placed reference member using an existing method. Then, the control device 7 may calculate the position and orientation of the reference member using the measurement head 52 attached to the processing head 2. The control device 7 may calibrate an attachment error of the measurement head 52 to the processing head 2 based on the difference between the position and orientation of the reference member calculated in advance and the position and orientation of the reference member calculated using the measurement head 52 attached to the processing head 2.

[0208] For example, when calculating a movement error of a machine tool 1 in which a measuring head 52 is attached to the spindle 21 of a machining head 2, the control device 7 may first attach a touch probe to the spindle 21 and use the touch probe to calculate the position and orientation of a reference member for calibrating the attachment error. In this case, the control device 7 may calculate the average value of coordinates calculated by rotating the spindle 21 by a predetermined angle and bringing the touch probe into contact with a measurement point on the reference member. For example, when calculating coordinates by rotating the spindle 21 by 90 degrees and bringing the touch probe into contact with the reference member, the control device 7 may calculate the average value of four coordinates calculated by bringing the touch probe into contact four times. Similarly, the control device 7 may calculate the average value of coordinates of other measurement points necessary to calculate the position and orientation of the reference member. The control device 7 may then calculate the position and orientation of the reference member based on the calculated average coordinate values ​​of each measurement point on the reference member. Next, the control device 7 replaces the touch probe attached to the spindle 21 with the measuring head 52 and uses the measuring head 52 to calculate the position and orientation of the reference member. The control device 7 may then calibrate the attachment error of the measuring head 52 to the spindle 21 of the machining head 2 based on the difference between the position and attitude of the reference member calculated by the touch probe and the position and attitude of the reference member calculated by the measuring head 52. In this case, the effect of the attachment error of the touch probe to the spindle 21 on the calculation results of the measurement point can be reduced by rotating the spindle 21 by a predetermined angle and calculating the average value of the coordinates calculated by bringing the touch probe into contact with the measurement point of the reference member.

[0209] The position of the reference member may include at least a part of the X component (i.e., the position in the X-axis direction), the Y component (i.e., the position in the Y-axis direction), and the Z component (i.e., the position in the Z-axis direction) in three-dimensional space. Furthermore, the orientation of the reference member may include at least a part of the θX component (i.e., the position in the θX direction), the θY component (i.e., the position in the θY direction), and the θZ component (i.e., the position in the θZ direction) in three-dimensional space.

[0210] The reference member used to calibrate the attachment error of the measuring head 52 to the processing head 2 may be permanently placed on the stage 41. Alternatively, the reference member may be placed on the stage 41 only when the attachment error is to be calibrated. The location where the reference member is placed does not have to be the stage 41. The reference member may be placed anywhere as long as it is placed at a position where it can be measured by the measuring head 52 attached to the processing head 41.

[0211] Furthermore, the reference member used to calibrate the attachment error of the measuring head 52 to the processing head 2 may be at least one of the above-mentioned reference members FM1, FM2, and FM3. For example, when the reference member FM1 is used to calibrate the attachment error of the measuring head 52 to the processing head 2, the control device 7 may calculate the position and orientation of the reference member FM1 by measuring the grid pattern GP of the reference member FM1 with the measuring head 52 as described above.

[0212] (4) Variations Next, a modified example of the machine tool 1 will be described.

[0213] (4-1) First Modification First, a first modified example of the machine tool 1 will be described. In the following description, the first modified example of the machine tool 1 will be referred to as "machine tool 1a." The machine tool 1a differs from the machine tool 1 in that it includes a measuring device 5a instead of the measuring device 5. Other features of the machine tool 1a may be the same as other features of the machine tool 1. The measuring device 5a differs from the measuring device 5 in that it includes a measuring head 52a instead of the measuring head 52. Other features of the measuring device 5a may be the same as other features of the measuring device 5. The measuring head 52a differs from the measuring head 52 in that it includes an optical system 522a instead of the optical system 522. Other features of the measuring head 52a may be the same as other features of the measuring head 52. The optical system 522a differs from the optical system 522 in that it can irradiate a measurement object with measurement light ML, which is parallel light (i.e., collimated light). Hereinafter, the optical system 522a in the first modified example will be described with reference to FIG. 31 . FIG. 31 is a cross-sectional view showing the structure of an optical system 522a in the first modified example.

[0214] 31, optical system 522a differs from optical system 522 in that optical system 522a includes a focusing optical system 5220a and a reflecting optical system 5229a instead of fθ lens 5228. Other features of optical system 522a may be the same as other features of optical system 522. Note that, for simplification of the drawing, some of the optical elements included in optical system 522a are omitted in FIG.

[0215] The focusing optical system 5220a focuses the measurement light ML near the X scanning mirror 52271 and the Y scanning mirror 52272 of the galvanometer mirror 5227, typically between the X scanning mirror 52271 and the Y scanning mirror 52272 of the galvanometer mirror 5227. The reflecting optical system 5229a reflects the measurement light ML emitted from the galvanometer mirror 5227 toward the measurement object (for example, the reference member FM). In the example shown in FIG. 31 , the reflecting optical system 5229a includes a reflecting optical element 52291a and a reflecting optical element 52292a, and has a finite focal length. The measurement light ML emitted from the galvanometer mirror 5227 is incident on a reflecting surface 52294a of the reflecting optical element 52292a via an opening 52293a formed in the reflecting optical element 52291a. The reflecting surface 52294a reflects the measurement light ML toward the reflecting surface 52295a of the reflecting optical element 52291a, which faces the reflecting surface 52294a. The reflecting surface 52295a reflects the measurement light ML toward the measurement object, which faces the reflecting surface 52295a. Here, the measuring light ML is focused (a focusing point is formed) at the front focal position (incident side) of the reflecting optical system 5229a by the focusing optical system 5220a, so that the measurement light ML, which is parallel light, can be irradiated onto the measurement object.

[0216] When the measurement object is irradiated with the measurement light ML, which is parallel light, the possibility of the measurement accuracy fluctuating due to defocusing of the measurement light ML is lower than when the measurement object is irradiated with the measurement light ML, which is convergent light. As a result, the possibility of the measurement accuracy fluctuating due to movement of at least one of the processing head 2 and the stage 41 (particularly movement in the direction along the optical path of the measurement light ML) is lower. Therefore, even when measuring the reference member FM while moving at least one of the processing head 2 and the stage 41, the measurement device 5a can measure the reference member FM with constant measurement accuracy. Therefore, the control device 7 can calculate the movement error with relatively high accuracy without being affected by fluctuations in the measurement accuracy of the measurement device 5a. Note that in the first modified example, the return light RL is a parallel light beam that travels backward along the optical path of the measurement light ML, which has been converted into parallel light, among the light generated from the reference member FM by irradiation with the measurement light ML.

[0217] (4-2) Second Modification Next, a second modified example of the machine tool 1 will be described. In the following description, the second modified example of the machine tool 1 will be referred to as "machine tool 1b." The machine tool 1b differs from the machine tool 1 in that it includes a measuring device 5b instead of the measuring device 5. Other features of the machine tool 1b may be the same as other features of the machine tool 1. The measuring device 5b differs from the measuring device 5 in that it includes a measuring head 52b instead of the measuring head 52. Other features of the measuring device 5b may be the same as other features of the measuring device 5. The measuring head 52b differs from the measuring head 52 in that it includes an optical system 522b instead of the optical system 522. Other features of the measuring head 52b may be the same as other features of the measuring head 52. The optical system 522b differs from the optical system 522 in that it can irradiate the measurement object with measurement light ML, which is parallel light (i.e., collimated light). Hereinafter, the optical system 522b in the second modified example will be described with reference to FIG. 32. FIG. 32 is a cross-sectional view showing the structure of an optical system 522b in the second modified example.

[0218] 32, the optical system 522b differs from the optical system 522 in that it includes a condensing optical system 5229b. Other features of the optical system 522b may be the same as other features of the optical system 522.

[0219] The focusing optical system 5229b is disposed on the optical path of the measurement light ML and the return light RL between the fθ lens 5228 and the detector 5226. In the example shown in FIG. 32, the focusing optical system 5229b is disposed on the optical path of the measurement light ML and the return light RL between the beam splitter 5224 and the galvanometer mirror 5227. The focusing optical system 5229b forms a focusing position of the measurement light ML at a focal position PP (or near the focal position PP, the same applies below) on the detector 5226 side of the fθ lens 5228. The focal position PP on the detector 5226 side of the fθ lens 5228 may be considered equivalent to the focal position on the spindle 21 side of the fθ lens 5228. The focal position PP on the detector 5226 side of the fθ lens 5228 may be considered equivalent to the focal position on the machining head 2 side of the fθ lens 5228. The focal position PP of the f-theta lens 5228 on the detector 5226 side may be considered to be equivalent to the focal position of the f-theta lens 5228 on the side opposite the measurement object side. The focal position PP of the f-theta lens 5228 on the detector 5226 side may be considered to be equivalent to the focal position of the f-theta lens 5228 on the side opposite the stage 41 side. The focal position PP of the f-theta lens 5228 on the detector 5226 side may coincide with the entrance-side pupil position of the f-theta lens 5228. In the example shown in FIG. 32 , the focal position PP of the f-theta lens 5228 on the detector 5226 side is located within the galvanometer mirror 5227. The focal position PP of the f-theta lens 5228 on the detector 5226 side is located on the optical path between the X-scanning mirror 52271 and the Y-scanning mirror 52272 of the galvanometer mirror 5227. However, the focal position PP of the f-theta lens 5228 on the detector 5226 side is not limited to the position shown in FIG. 32 . The focal position PP of the fθ lens 5228 on the detector 5226 side may be located at a position independent of the galvanometer mirror 5227. Even if the measurement head 52b does not include the galvanometer mirror 5227, the focal position PP of the fθ lens 5228 on the detector 5226 side may be located at an appropriate position on the optical path between the fθ lens 5228 and the detector 5226. 32, the light collecting optical system 5229b includes a single lens (i.e., a refractive optical element). However, the light collecting optical system 5229b may include multiple refractive optical elements. The light collecting optical system 5229b does not have to include a refractive optical element. The light collecting optical system 5229b may include at least one reflective optical element.

[0220] 32, the measurement light ML, which is parallel light, is emitted from the fθ lens 5228. Therefore, in the second modification, as in the first modification, the control device 7 can calculate the movement error with relatively high accuracy without being affected by fluctuations in the measurement accuracy of the measurement device 5b. Note that in the second modification as well, the return light RL is a parallel luminous flux that travels backward along the optical path of the measurement light ML, which has been converted into parallel light, among the light generated from the reference member FM by irradiation with the measurement light ML.

[0221] The collecting optical system 5229b may be movable with respect to the optical paths of the measurement light ML and the return light RL. Specifically, for example, the measurement head 52b may include a drive system 54b that can move the collecting optical system 5229b. The drive system 54b may move the collecting optical system 5229b to insert or remove the collecting optical system 5229b into or from the optical paths of the measurement light ML and the return light RL. By moving the collecting optical system 5229b, the drive system 54b may switch the state of the collecting optical system 5229b between a state in which the collecting optical system 5229b is located on the optical paths of the measurement light ML and the return light RL and a state in which the collecting optical system 5229b is not located on the optical paths of the measurement light ML and the return light RL.

[0222] When the focusing optical system 5229b is located on the optical paths of the measurement light ML and the return light RL, the measurement light ML emitted from the fθ lens 5228 becomes parallel light, as shown in Fig. 32. On the other hand, when the focusing optical system 5229b is not located on the optical paths of the measurement light ML and the return light RL, the measurement light ML emitted from the fθ lens 5228 becomes convergent light, as shown in Fig. 33.

[0223] The drive system 54b may switch the state of the collecting optical system 5229b between a state in which the collecting optical system 5229b is located on the optical paths of the measurement light ML and the return light RL and a state in which the collecting optical system 5229b is not located on the optical paths of the measurement light ML and the return light RL, depending on the type of measurement object. For example, if the measurement object is a first object, the drive system 54b may move the collecting optical system 5229b so that the collecting optical system 5229b is located on the optical paths of the measurement light ML and the return light RL. For example, if the measurement object is a second object different from the first object, the drive system 54b may move the collecting optical system 5229b so that the collecting optical system 5229b is not located on the optical paths of the measurement light ML and the return light RL.

[0224] As an example, when a reference member FM is placed on the stage 41 as the measurement object, the drive system 54b may move the condensing optical system 5229b so that the condensing optical system 5229b is positioned on the optical paths of the measurement light ML and the return light RL. In this case, as described above, the control device 7 can calculate the measurement error with relatively high accuracy without being affected by fluctuations in the measurement accuracy of the measuring device 5b. On the other hand, when the measurement object is a workpiece W, the drive system 54b may move the condensing optical system 5229b so that the condensing optical system 5229b is not positioned on the optical paths of the measurement light ML and the return light RL. In this case, the diameter of the spot formed by the measurement light ML on the surface of the workpiece W becomes relatively small as described above, and therefore the measuring device 5 can measure the workpiece W with relatively high measurement accuracy.

[0225] The machine tool 1a in the first modified example described above may be provided with components specific to the second modified example. The components specific to the second modified example may include components related to the optical system 522b.

[0226] The focusing optical system 5220a in the first modified example described above may be the same as the focusing optical system 5229b in the second modified example. That is, the focusing optical system 5229b in the second modified example may be used as the focusing optical system 5220a in the first modified example described above. In this case, the positional relationship between the focusing optical system 5220a and the galvanometer mirror 5227 in the first modified example may be the same as the positional relationship between the focusing optical system 5229b and the galvanometer mirror 5227 in the second modified example.

[0227] In the first and second modified examples described above, the focusing optical system 5220a or 5229b is arranged on the light source and / or detector side of the fθ lens 5228 and reflecting optical system 5229a as the objective optical system to collimate the measurement light ML. However, a diverging optical system may be arranged on the reference member FM side or workpiece W side of the fθ lens 5228 and reflecting optical system 5229a as the objective optical system to collimate the measurement light ML. In this case, the diverging optical system typically has a negative focal length, and its focal position coincides with the focal plane of the fθ lens 5228 and reflecting optical system 5229a as the objective optical system. The diverging optical system may then be moved to follow the irradiation position of the measurement light ML on the reference member FM or workpiece W so that the beam center of the measurement light ML and the optical axis of the diverging optical system are coaxial. Furthermore, this diverging optical system does not need to be moved, and a similar diverging optical system may be placed on each optical path of the measurement light ML from the fθ lens 5228, which may change depending on the change in the irradiation position of the measurement light ML on the reference member FM or the workpiece W.

[0228] (4-3) Third Modification Next, a third modified example of the machine tool 1 will be described. In the following description, the first modified example of the machine tool 1 will be referred to as "machine tool 1c." The machine tool 1c differs from the machine tool 1 in that, when measuring the measurement object while changing the positional relationship between the measurement head 52 and the measurement object along a direction intersecting the optical path of the measurement light ML (i.e., a direction intersecting the traveling direction of the measurement light ML), the measurement fields of view MSA may be partially overlapped. Other features of the machine tool 1c may be the same as other features of the machine tool 1.

[0229] 34 showing a measurement head 52 irradiating a reference member FM, which is an example of a measurement object, with measurement light ML, the measurement head 52 may measure a first portion FMa1 of the reference member FM1 when the positional relationship between the stage 41 and the processing head 2 in a direction intersecting the optical path of the measurement light ML (the X-axis direction in the example shown in FIG. 34) is a first relationship. Specifically, at least one of the head drive system 3 and the stage drive system 42 may move at least one of the processing head 2 (and further, the measurement head 52) and the stage 41 so that the positional relationship between the stage 41 and the processing head 2 in the direction intersecting the optical path of the measurement light ML is a first relationship in which the first portion FMa1 of the reference member FM1 is included in a measurement field of view MSA of the measurement device 5. The measurement field of view MSA may be a scanning area that can be scanned by the galvanometer mirror 5227 with the measurement light ML while the positional relationship between the measurement head 52 and the measurement object is fixed. In other words, the measurement field of view MSA may be a scanning area that can be scanned by the galvanometer mirror 5227 with the measurement light ML when the machining head 2 (further, the measurement head 52) and the stage 41 do not move. Thereafter, the measurement head 52 may irradiate the first portion FMa1 with the measurement light ML traveling along the optical path OP41 from the fθ lens 5228. Furthermore, the measurement head 52 may receive, as returned light RL from the first portion FMa1, a light component traveling along the optical path OP41 of the light from the first portion FMa1 that is generated by the measurement light ML irradiated onto the first portion FMa1. Thereafter, at least one of the head drive system 3 and the stage drive system 42 may move at least one of the machining head 2 (further, the measurement head 52) and the stage 41 so that the positional relationship between the stage 41 and the machining head 2 in a direction intersecting the optical path of the measurement light ML becomes a second relationship in which the second portion FMa2 of the reference member FM1 is included in the measurement field of view MSA of the measurement device 5. The second portion FMa2 partially overlaps with the first portion FMa1. That is, the second portion FMa2 includes a part of the first portion FMa1. Conversely, the first portion FMa1 includes a part of the second portion FMa2. Thereafter, the measurement head 52 may irradiate the second portion FMa2 with the measurement light ML traveling from the fθ lens 5228 along the optical path OP42.Furthermore, the measurement head 52 may receive, as return light RL from the second portion FMa2, a light component that travels along the optical path OP42 out of the light from the second portion FMa2 that is generated by the measurement light ML irradiated onto the second portion FMa2. The machine tool 1c may repeat the above operations as many times as necessary.

[0230] Thereafter, the control device 7 may calculate the movement error based on the measurement results by the measurement device 5, including the measurement results of the first portion FMa1 and the second portion FMa2. Specifically, the control device 7 may calculate the position of the first portion FMa1 based on the detection results of the return light RL from the first portion FMa1. The control device 7 may calculate the position of the second portion FMa2 based on the detection results of the return light RL from the second portion FMa2. Thereafter, the control device 7 may merge the calculation results of the position of the first portion FMa1 and the calculation results of the position of the second portion FMa2. Specifically, the control device 7 calculates the positions of feature points common to the first portion FMa1 and the second portion FMa2 based on the calculation results of the position of the first portion FMa1. Furthermore, the control device 7 calculates the positions of feature points common to the first portion FMa1 and the second portion FMa2 based on the calculation results of the position of the second portion FMa2. Thereafter, the control device 7 may merge the calculation result of the position of the first part FMa1 and the calculation result of the position of the second part FMa2 so that the calculated positions of the feature points match, and then the control device 7 may calculate a movement error based on the merged result.

[0231] Here, when no movement error occurs, the first part FMa1 and the second part FMa2 are merged so as to neatly overlap via the common part FMac common to both the first part FMa1 and the second part FMa2, as shown in FIG. 35(a), which schematically shows the merge result when no movement error occurs. On the other hand, when a movement error occurs, the first part FMa1 and the second part FMa2 are merged so as to have a deviation caused by the movement error, as shown in FIG. 35(b), which schematically shows the merge result when a movement error occurs. Therefore, the control device 7 may calculate the movement error by calculating the deviation between the first part FMa1 and the second part FMa2 that appears in the merge result. Hereinafter, the movement error E X An example of calculating the above will be described.

[0232] For example, as shown in FIG. 36(a), the control device 7 calculates a movement error E based on the amount of deviation Δx in the X-axis direction between the end of the first portion FMa1 (i.e., the end of the measurement field of view MSA when the first portion FMa1 is measured) and the end of the second portion FMa2 (i.e., the end of the measurement field of view MSA when the second portion FMa2 is measured). XX Specifically, the movement error E XX If no deviation Δx occurs, the deviation Δx should match the target value of the movement amount of the processing head 2 in the X-axis direction. XX When this occurs, the deviation Δx does not match the target value of the movement amount of the machining head 2 in the X-axis direction. Therefore, the control device 7 calculates the deviation Δx, and determines the difference between the calculated deviation Δx and the target value of the movement amount of the machining head 2 in the X-axis direction as the movement error E XX It may be calculated as:

[0233] For example, as shown in FIG. 36(a), the control device 7 calculates a movement error E based on the deviation Δy in the Y-axis direction between the end of the first portion FMa1 and the end of the second portion FMa2. YX Specifically, the movement error E YX If no error occurs, the deviation Δy should be zero. YXIf the deviation amount Δy is equal to or greater than zero, the control device 7 calculates the deviation amount Δy as the movement error E YX It may be calculated as:

[0234] For example, as shown in FIG. 36(b), the control device 7 calculates a movement error E based on the deviation amount Δz in the Z-axis direction between the feature point of the first portion FMa1 and the feature point of the second portion FMa2. ZX Specifically, the movement error E ZX If no error occurs, the deviation Δz should be zero. ZX If this occurs, the deviation amount Δz will not be zero. Therefore, the control device 7 calculates the deviation amount Δz as the movement error E ZX It may be calculated as:

[0235] For example, as shown in FIG. 36(c), the control device 7 calculates a movement error E based on a difference Δz11 between the Z positions of two feature points of the first portion FMa1 located at different positions along the Y axis direction and a difference Δz12 between the Z positions of the same two feature points of the second portion FMa2 located at different positions along the Y axis direction. AX Specifically, the movement error E AX If no difference Δz11 and difference Δz12 occur, they should match. AX When this occurs, the difference Δz11 and the difference Δz12 do not match. Therefore, the control device 7 calculates the difference Δz11 and the difference Δz12, and determines the difference between the difference Δz11 and the difference Δz12 as the movement error E BX It may be calculated as:

[0236] For example, as shown in FIG. 36(d), the control device 7 calculates a movement error E based on a difference Δz21 between the Z positions of two feature points of the first portion FMa1 located at different positions along the X axis direction and a difference Δz22 between the Z positions of the same two feature points of the second portion FMa2 located at different positions along the X axis direction. BX Specifically, the movement error E BX If no movement error E occurs, the difference Δz21 and the difference Δz22 should match. BXWhen this occurs, the difference Δz21 and the difference Δz22 do not match. Therefore, the control device 7 calculates the difference Δz21 and the difference Δz22, and determines the difference between the difference Δz21 and the difference Δz22 as the movement error E BX It may be calculated as:

[0237] For example, as shown in FIG. 36(e), the control device 7 calculates a movement error E based on the difference Δθ between the amount of rotation of the first portion FMa1 around the C axis (i.e., the amount of rotation of the measurement field of view MSA when measuring the first portion FMa1) and the amount of rotation of the second portion FMa2 around the C axis (i.e., the amount of rotation of the measurement field of view MSA when measuring the second portion FMa2). CX Specifically, the movement error E CX If no error occurs, the difference Δθ should be zero. CX If this occurs, the difference Δθ will not be zero. Therefore, the control device 7 converts the difference Δθ into the movement error E CX It may be calculated as:

[0238] In this third modified example, the control device 7 can perform the movement error calculation operation using the workpiece W machined by the machining head 2, etc., without using the reference member FM. Specifically, at least one of the machining head 2 and the stage 41 usually moves so that machining is performed on the workpiece W to shape the workpiece W into a desired shape. Here, if a movement error occurs, at least one of the machining head 2 and the stage 41 will move along a movement path different from the designed movement path (e.g., the movement path indicated by the above-mentioned movement path information). As a result, the shape of the machined workpiece W will differ from the desired shape. For example, the shape of the machined workpiece W will reflect distortion of a guide member provided in at least one of the head drive system 3 and the stage drive system 41, which is one cause of the movement error. Even when the measuring device 5 processes such a workpiece W, because the measuring head 52 moves together with the machining head 2, the movement of the measuring head 52 during measurement of the workpiece W will also generate a movement error that occurs in the movement of the machining head 2 during machining of the workpiece W. Therefore, the measurement results of the workpiece W by the measurement head 52, which has moved along a movement path including a movement error, will erroneously indicate that the shape of the workpiece W is the desired shape. However, as described above, when the measurement device 5 measures the workpiece W while at least one of the machining head 2 and the stage 41 is stopped, the measurement device 5 can accurately measure the position (shape) of at least the portion of the workpiece W that is included in the measurement field of view MSA. Therefore, as shown in Figures 36(a) to 36(e), the movement error that occurs in the movement of at least one of the machining head 2 and the stage 41 appears as a discrepancy between the measurement results of a first portion of the workpiece W and the measurement results of a second portion of the workpiece W that partially overlaps the first portion. Therefore, the control device 7 can perform the movement error calculation operation using the workpiece W (or any other object) machined by the machining head 2 without using the reference member FM.

[0239] At least one of the machine tool 1a in the first modified example to the machine tool 1b in the second modified example described above may include components specific to the third modified example. The components specific to the third modified example may include components related to measurement of a first portion of the measurement object and a second portion of the measurement object that partially overlaps with the first portion.

[0240] (4-4) Fourth Modification Next, a fourth modified example of the machine tool 1 will be described. In the following description, the fourth modified example of the machine tool 1 will be referred to as "machine tool 1d." The machine tool 1d differs from the machine tool 1 in that it includes a measuring device 5d instead of the measuring device 5. Other features of the machine tool 1d may be the same as other features of the machine tool 1. The measuring device 5d differs from the measuring device 5 in that it includes measuring heads 52d-1 and 52d-2 instead of the measuring head 52. Other features of the measuring device 5d may be the same as other features of the measuring device 5. Hereinafter, measuring heads 52d-1 and 52d-2 in the fourth modified example will be described with reference to FIG. 37. FIG. 37 is a cross-sectional view showing the structure of measuring heads 52d-1 and 52d-2 in the fourth modified example.

[0241] As shown in FIG. 37 , each of the measurement heads 52d-1 and 52d-2 is attached to the processing head 2. However, the measurement heads 52d-1 and 52d-2 are attached to different parts of the processing head 2. Specifically, the measurement head 52d-1 is attached to a part of the processing head 2 that is different from the spindle 21. In the example shown in FIG. 37 , the head housing 521d-1 of the measurement head 52d-1 is attached to the head housing 22 of the processing head 2. On the other hand, the measurement head 52d-2 is attached to the spindle 21 of the processing head 21. Specifically, the head housing 521d-2 of the measurement head 52d-2 is attached to the spindle 21. The measurement head 52d-1 includes an optical system 522d-1 that includes a part of the optical system 522 included in the measurement head 52. The measurement head 52d-2 includes an optical system 522d-2 that includes another part of the optical system 522 included in the measurement head 52. Therefore, the measurement heads 52d-1 and 52d-2 correspond to two heads obtained by dividing the measurement head 52 described above.

[0242] The optical system 522d-1 emits measurement light ML from the measurement light source 51 toward the optical system 522d-2. The optical system 522d-2 emits measurement light ML from the optical system 522d-1 toward the measurement object. The optical system 522d-2 emits return light RL from the measurement object toward the optical system 522d-1. The optical system 522d-1 receives return light RL from the optical system 522d-2.

[0243] The optical system 522d-1 may include an optical system 5220d-1 and a mirror 5229d-1 to emit measurement light ML from the measurement light source 51 toward the optical system 522d-2 and receive return light RL from the optical system 522d-2. Furthermore, the optical system 522d-2 includes a mirror 5229d-2 and an fθ lens 5228 to emit measurement light ML from the optical system 522d-1 toward the measurement object and emit return light RL from the measurement object toward the optical system 522d-1. The optical system 522d-2 may further include a deflector 523 to change the traveling direction of the measurement light ML.

[0244] As shown in FIG. 38 , the optical system 5220d-1 differs from the optical system 522 in that it does not need to include an fθ lens 5228. Other features of the optical system 5220d-1 may be the same as those of the optical system 522. The optical system 5220d-1 emits measurement light ML from the measurement light source 51 toward a mirror 5229d-1. Specifically, the measurement light ML from the galvanometer mirror 5227 is incident on the mirror 5229d-1. The mirror 5229d-1 reflects the measurement light ML from the optical system 5220d-1 toward the optical system 522d-2. The measurement light ML from the optical system 522d-1 is incident on a mirror 5229d-2 of the optical system 522d-2. The mirror 5229d-2 reflects the measurement light ML from the optical system 522d-1 toward the fθ lens 5228. The fθ lens 5228 irradiates the measurement object with the measurement light ML from the mirror 5229d-2. That is, the optical system 522d-2 irradiates the measurement object with the measurement light ML via the fθ lens 5228.

[0245] Return light RL from the measurement object is incident on mirror 5229d-2 via fθ lens 5228. Mirror 5229d-1 reflects the return light RL from the measurement object toward optical system 522d-1. That is, optical system 522d-2 emits the return light RL from the measurement object toward optical system 522d-1 via fθ lens 5228. Return light RL from optical system 522d-2 is incident on mirror 5229d-1 of optical system 522d-1. Mirror 5229d-1 reflects measurement light RL from optical system 522d-2 toward optical system 5220d-1 (particularly, galvanometer mirror 5227). As a result, detector 5226 included in optical system 5220d-1 receives the return light RL.

[0246] Even with the machine tool 1d of the fourth modified example, it is possible to enjoy the same effects as those that can be enjoyed by the above-described machine tool 1. Furthermore, the measuring head 52d-1 attached to the head housing 22, rather than the measuring head 52d-2 detachably attached to the spindle 21, is equipped with the galvanometer mirror 5227, which tends to occupy a large volume, so that the size of the measuring head 52d-2 can be made small enough to be handled by the tool changer 6.

[0247] At least one of the machine tool 1a in the first modified example to the machine tool 1c in the third modified example described above may be provided with components specific to the fourth modified example. The components specific to the fourth modified example may include components related to the measuring heads 52d-1 and 52d-2.

[0248] (4-5) Fifth Modification Next, a fifth modified example of the machine tool 1 will be described with reference to Fig. 39. In the following description, the fifth modified example of the machine tool 1 will be referred to as "machine tool 1e." Fig. 39 is a system configuration diagram showing the system configuration of the machine tool 1e in the fifth modified example.

[0249] As shown in FIG. 39, machine tool 1e differs from machine tool 1 in that it includes a machining head 2e instead of machining head 2. Other features of machine tool 1e may be the same as other features of machine tool 1. Machining head 2e differs from machining head 2 in that it can machine workpiece W using machining light instead of tool 23. Note that the machining light used by machining head 2e to machine workpiece W is different from measurement light ML used by measurement device 5 to measure the measurement object. Other features of machining head 2e may be the same as other features of machining head 2.

[0250] In order to machine the workpiece W using the machining light, the machining head 2e may be equipped with a machining optical system 21e. The machining optical system 21e may be housed in a head housing of the machining head 2e. The machining optical system 21e may be attached to the machining head 2e. The machining optical system 21e emits machining light generated by a machining light source (not shown) toward the workpiece W. For this reason, the machining optical system 21e may be referred to as a machining light emitting unit. The machine tool 1e may machine the workpiece W by irradiating the workpiece W with machining light from the machining optical system 21e while moving at least one of the machining head 2e and the stage 41. For example, the machine tool 1e may perform additive machining on the workpiece W by irradiating the workpiece W with the machining light. The machine tool 1e may perform subtractive machining on the workpiece W by irradiating the workpiece W with the machining light. Note that the machine tool 1e that machines the workpiece W using the machining light may be referred to as an optical machining machine. The machining optical system 21e may be referred to as a processing unit for processing (here, processing) the workpiece W.

[0251] In the fifth modified example, the control device 7 may also perform a movement error calculation operation to calculate a movement error occurring in the movement of at least one of the machining head 2e and the stage 41, based on the measurement results from the measuring device 5. As a result, the fifth modified example can also provide the same effects as those that can be provided by the machine tool 1 described above.

[0252] If the processing optical system 21e is detachable from the processing head 2e, the measurement head 52 may be attached to the mounting portion of the processing head 2e to which the processing optical system 21e is attached. If the measurement head 52 is separable into measurement heads 52d-1 and 52d-2 as in the fourth modified example, the measurement head 52d-2 equipped with the fθ lens 5228 may be attached to the mounting portion of the processing head 2e to which the processing optical system 21e is attached. If the processing optical system 21e is not detachable from the processing head 2e, the measurement head 52 may be attached at a position relatively close to the mounting portion of the processing head 2e to which the processing optical system 21e is attached. The measurement head 52 may be attached as close as possible to the mounting portion of the processing head 2e to which the processing optical system 21e is attached. When the measurement head 52 can be divided into measurement heads 52d-1 and 52d-2 as in the fourth modified example, the measurement head 52d-2 equipped with the fθ lens 5228 may be attached at a position relatively close to the attachment portion of the processing head 2e to which the processing optical system 21e is attached. The measurement head 52d-2 may be attached at a position as close as possible to the attachment portion of the processing head 2e to which the processing optical system 21e is attached.

[0253] Furthermore, the machine tool 1e may process the workpiece W by irradiating the workpiece W with an energy beam different from light, called processing light. At least one of a charged particle beam (e.g., an electron beam or an ion beam) and an electromagnetic wave may be used as the energy beam.

[0254] It should be noted that the machining head 2e does not necessarily have to be movable. The head drive system 3 does not have to move the machining head 2e. The machine tool 1e does not have to be equipped with the head drive system 3. When the machining head 2e does not move, the machining head 2e may be simply referred to as the head 2e.

[0255] At least one of the machine tools 1a in the first modified example to 1d in the fourth modified example described above may be provided with components specific to the fifth modified example. The components specific to the fifth modified example may include components related to the machining head 2e.

[0256] (4-6) Sixth Modification Next, a sixth modified example of the machine tool 1 will be described. In the following description, the sixth modified example of the machine tool 1 will be referred to as "machine tool 1f." The machine tool 1f differs from the machine tool 1 in that it does not have to be able to machine the workpiece W. In this case, as shown in Figure 40, which is a system configuration diagram showing the system configuration of the machine tool 1f in the sixth modified example, the machine tool 1f may be equipped with an optional moving head 2f that can be moved by a head drive system 3, instead of the machining head 2. Other features of the machine tool 1f may be the same as other features of the machine tool 1. In addition, because the machine tool 1f does not have to be able to machine the workpiece W, in order to eliminate any misunderstanding that may arise from the term "machine tool," in the following description, the machine tool 1f equipped with the moving head 2f will be referred to as "moving device 1f." 40, the moving head 2f differs from the processing head 2 in that it may not be capable of processing the workpiece W. Other features of the moving head 2f may be the same as other features of the processing head 2.

[0257] The moving head 2f may be equipped with a measuring device (measuring unit) 21f. The measuring device 21f may be housed in a head housing of the moving head 2f. The measuring device 21f may be attached to the moving head 2f. The measuring device 21f is capable of measuring a measurement object. The measurement object measured by the measuring device 21f may be the same as or different from the measurement object measured by the measuring device 5. As an example, the measuring device 21f may be capable of measuring a workpiece W. The measuring device 21f may be capable of measuring a measurement object without contact. The measuring device 21f may be capable of optically measuring a measurement object. The measuring device 21f may be capable of electrically measuring a measurement object. The measuring device 21f may be capable of magnetically measuring a measurement object. The measuring device 21f may be capable of thermally measuring a measurement object. The measuring device 21f may be capable of measuring a measurement object using a probe that physically contacts the measurement object.

[0258] The moving device 1f may measure the measurement object using the measuring device 21f while moving at least one of the moving head 2f and the stage 41. Note that if the moving head 2f is equipped with a measuring device 91f capable of measuring the workpiece W, the moving head 2f may be referred to as a workpiece measuring head. If the moving head 2f is equipped with a measuring device 91f, the moving device 1f may be referred to as a measuring machine or a measuring device. The moving device 1f may be capable of functioning as a coordinate measuring machine (CMM). If the measuring device 91f is capable of measuring the workpiece W, the measuring device 91f may be referred to as a processing unit for processing (here, measuring) the workpiece W.

[0259] In this sixth modified example as well, the control device 7 may perform a movement error calculation operation to calculate a movement error occurring in the movement of at least one of the moving head 2f and the stage 41, based on the measurement results from the measuring device 5. As a result, in the sixth modified example as well, it is possible to enjoy the same effects as those that can be enjoyed by the machine tool 1 described above.

[0260] Note that if the measuring device 21f is detachable from the moving head 2f, the measuring head 52 may be attached to the mounting portion of the moving head 2f to which the measuring device 21f is attached. If the measuring head 52 is separable into measuring heads 52d-1 and 52d-2 as in the fourth modified example, the measuring head 52d-2 equipped with the fθ lens 5228 may be attached to the mounting portion of the moving head 2f to which the measuring device 21f is attached. If the measuring device 21f is not detachable from the moving head 2f, the measuring head 52 may be attached in a position relatively close to the mounting portion of the moving head 2f to which the measuring device 21f is attached. The measuring head 52 may be attached as close as possible to the mounting portion of the moving head 2f to which the measuring device 21f is attached. When the measurement head 52 can be divided into measurement heads 52d-1 and 52d-2 as in the fourth modified example, the measurement head 52d-2 equipped with the fθ lens 5228 may be attached at a position relatively close to the attachment portion of the moving head 2f to which the measurement device 21f is attached. The measurement head 52d-2 may be attached at a position as close as possible to the attachment portion of the processing head 2f to which the measurement device 21f is attached.

[0261] It should be noted that the moving head 2f does not necessarily have to be movable. The head drive system 3 does not have to move the moving head 2f. The moving device 1f does not have to be equipped with the head drive system 3. When the moving head 2f does not move, the moving head 2f may simply be referred to as the head 2f. When the moving head 2f does not move, the moving device 1f may be referred to as a processing device.

[0262] At least one of the machine tools 1a in the first modified example to the machine tool 1e in the fifth modified example described above may be provided with components specific to the sixth modified example. The components specific to the sixth modified example may include components related to the moving head 2f.

[0263] (4-7) Seventh Modification Next, a seventh modified example of the machine tool 1 will be described. In the following description, the seventh modified example of the machine tool 1 will be referred to as "machine tool 1g." The machine tool 1g differs from the machine tool 1 in that it is equipped with a head drive system 3g instead of the head drive system 3. Other features of the machine tool 1g may be the same as other features of the machine tool 1. Hereinafter, the head drive system 3g in the seventh modified example will be described with reference to FIG. 41. FIG. 41 is a side view showing the structure of the head drive system 3g in the seventh modified example.

[0264] As shown in FIG. 41 , the head drive system 3g may differ from the head drive system 3 in that it is a robot arm. The robot arm may be a manipulator with three or more degrees of freedom. The robot arm may function as a robot having a so-called vertical multi-joint structure. The robot arm may function as a polar coordinate robot having a horizontal multi-joint structure. The robot arm may function as a cylindrical coordinate robot. The robot arm may function as a Cartesian coordinate robot. The robot arm may function as a parallel link robot. A machining head 2 may be attached to the tip of the robot arm. In other words, the machining head 2 may be attached to the robot arm as an end effector. The other features of the head drive system 3g may be the same as those of the head drive system 3. In this case, a measuring head 52 may be attached to the machining head 2, or a measuring head 52 in a modified example (e.g., at least one of measuring heads 52a, 52b, 52d-1, and 52d-2) may be attached instead of the measuring head 52. Alternatively, at least one of the measuring heads 52, 52a, 52b, 52d-1 and 52d-2 may be attached to the tip of a robot arm to which the processing head 2 is attached.

[0265] In the seventh modified example, the control device 7 may also perform a movement error calculation operation to calculate a movement error occurring in the movement of at least one of the machining head 2 attached to the robot arm and the stage 41, based on the measurement results from the measurement device 5. As a result, the seventh modified example can also achieve the same effects as those that can be achieved by the machine tool 1 described above.

[0266] (4-8) Other variations In the above description, the measurement device 5 is an interferometric measurement device that uses an optical frequency comb light source as the measurement light source 51. However, the measurement device 5 may also be an interferometric measurement device that uses a light source other than the optical frequency comb light source as the measurement light source 51. For example, the measurement device 5 may be an optical coherence tomography (OCT) measurement device. An example of an OCT measurement device is described in Japanese Patent Application Laid-Open No. 2020-101499. For example, the measurement device 5 may be a measurement device equipped with a white light confocal displacement meter. An example of a white light confocal displacement meter is described in Japanese Patent Application Laid-Open No. 2020-085633. For example, the measurement device 5 may be a phase modulation measurement device. An example of a phase modulation measurement device is described in Japanese Patent Application Laid-Open No. 2010-025922. For example, the measurement device 5 may be an intensity modulation measurement device. An example of an intensity modulation type measurement device is described in Japanese Patent Application Laid-Open No. 2016-510415 and US Patent Application Publication No. 2014 / 226145.

[0267] In the above description, the control device 7 included in the machine tool 1 performs a first operation of acquiring measurement results from the measuring device 5, a second operation of calculating the position of the reference member FM based on the measurement results from the measuring device 5, a third operation of calculating a movement error based on the position of the reference member FM, and a fourth operation of calibrating at least one of the coordinate information and the drive signal based on the movement error. However, at least one of the first to fourth operations may be performed by another control device (arithmetic device) different from the control device 7 included in the machine tool 1. For example, the control device 7 may perform the first and second operations, the other control device may perform the third operation based on the position of the reference member FM calculated by the control device 7, and the control device 7 may perform the fourth operation based on the movement error calculated by the other control device 7.

[0268] The movement error may vary depending on the environmental temperature around the machine tool 1. For this reason, the control device 7 may calculate a plurality of movement errors corresponding to a plurality of different environmental temperatures. In this case, the control device 7 may select one movement error that corresponds to the actual environmental temperature around the machine tool 1 from the plurality of movement errors, and control the machine tool 1 using the selected one movement error.

[0269] In the above description, the machine tool 1 is provided with the head drive system 3. In other words, the machining head 2 is movable. However, the machine tool 1 does not have to be provided with the head drive system 3. In other words, the machining head 2 does not have to be movable.

[0270] In the above description, the machine tool 1 is provided with the stage drive system 42. That is, the stage 41 is movable. However, the machine tool 1 does not necessarily have to be provided with the stage drive system 42. That is, the stage 41 does not necessarily have to be movable.

[0271] In the above-described embodiment and the first to fifth modified examples, a machining center has been used as an example of a machine tool. However, the machine tool is not limited to a machining center and may be, for example, at least one of a turning center, lathe, milling machine, grinding machine, polishing machine, lapping machine, honing machine, band saw, drilling machine, boring machine, gear cutting machine, scraping machine, and electric discharge machine. The machine tool may also be any machine that processes a material into a predetermined shape and dimensions. If the machine tool is a grinding machine, measuring heads 52 and 52b may be attached to a head (processing head) to which a grinding wheel is attached. Measuring head 52 (or at least one of measuring heads 52a, 52b, 52d-1, and 52d-2) may be attached to the head to which a grinding wheel is attached, instead of the grinding wheel attached to the attachment portion. The measuring head 52 (or at least one of the measuring heads 52a, 52b, 52d-1 and 52d-2) may be detachably attached to a head to which the grindstone is attached.

[0272] (5) Supplementary Notes The following additional notes are provided regarding the above-described embodiment. [Appendix 1] A calculation device for calculating a movement error occurring in the movement of at least one of a mounting device capable of mounting a workpiece and a head capable of attaching a processing unit for processing the workpiece, The head includes an objective optical system that irradiates a first light toward a reference member placed on the mounting device, and a detector that receives, via the objective optical system, a second light from the reference member that is generated by the irradiation of the first light, and a calculation unit that calculates the movement error based on a detection result by a light detection device attached to the head. Calculation device. [Appendix 2] The apparatus further includes an output unit that outputs the movement error calculated by the calculation unit. 10. The computing device of claim 1. [Appendix 3] the detector receives interference light between a portion of the first light and at least a portion of the second light; The calculation unit calculates the movement error based on the detection result of the interference light. 3. The computing device of claim 1 or 2. [Appendix 4] The calculation unit calculates a position of at least a part of the reference member based on a detection result of the interference light, and calculates the movement error based on the calculation result of the position. 4. The computing device of claim 3. [Appendix 5] The calculation unit calibrates information used for movement control of at least one of the placement device and the head based on the calculated movement error. 5. The computing device of any one of claims 1 to 4. [Appendix 6] The second light is light that travels along the optical path of the first light, among the light from the reference member that is generated by irradiation with the first light. 6. The computing device of any one of appendices 1 to 5. [Appendix 7] The light detection device further includes a focusing optical system that is provided in an optical path between the objective optical system and the detector and that forms a focusing point of the first light at a focal position on the detector side of the objective optical system. 7. The computing device of any one of claims 1 to 6. [Appendix 8] The light detection device further includes an insertion / removal device for inserting and removing the focusing optical system into and from the optical path. 8. The computing device of claim 7. [Appendix 9] The light detection device further includes a traveling direction changing member that can change the traveling direction of the first light toward the objective optical system so that the irradiation position of the first light on the reference member changes. 9. The computing device of any one of appendices 1 to 8. [Appendix 10] the first light, which is propagated in a first direction by the propagating direction changing member and is incident on the objective optical system, is propagated along a first optical path and is irradiated onto a first position of the reference member; the second light traveling along the first optical path from the first position generated by the first light irradiated at the first position is incident on the detector; the first light travels in a second traveling direction different from the first traveling direction by the traveling direction changing member and is incident on the objective optical system, travels along a second optical path different from the first optical path, and is irradiated onto a second position different from the first position of the reference member, the second light traveling along the second optical path from the second position generated by the first light irradiated to the second position is incident on the detector; The calculation unit calculates the movement error based on the detection results of the light detection device at each of the first position and the second position. 10. The computing device of claim 9. [Appendix 11] when the first light is irradiated from the objective optical system to the first position of the reference member, the objective optical system is located at a third position; When the first light is irradiated from the objective optical system to the second position on the reference member, the objective optical system is located at the third position. 11. The computing device of claim 10. [Appendix 12] the reference member includes a first region, a second region having a different characteristic from that of the first region, a third region, a fourth region having a different characteristic from that of the third region, a fifth region, and a sixth region having a different characteristic from that of the fifth region; The calculation unit calculates the movement error based on the position of a first boundary extending in a first direction and being a boundary between the first region and the second region, the position of a second boundary extending in a second direction intersecting with the first direction and being a boundary between the third region and the fourth region, and the position of a third boundary extending in a third direction intersecting with the second direction and being a boundary between the fifth region and the sixth region. 12. The computing device of claim 10 or 11. [Appendix 13] The light detection device further includes a deflection member that deflects the first light from the objective optical system toward the reference member. 13. The computing device of any one of claims 1 to 12. [Appendix 14] At least one of the mounting device and the head is movable along a first direction; The calculation unit calculates, based on a detection result by the light detection device, a motion error in a second direction and a motion error in a third direction different from the second direction that occur in the movement of at least one of the mounting device and the head when at least one of the mounting device and the head moves along the first direction. 14. The computing device of any one of claims 1 to 13. [Appendix 15] the detector receives the second light traveling along the first optical path among the light from the reference member generated by irradiating the reference member with the first light traveling along the first optical path from the objective optical system when a positional relationship between the mounting device and the head in the first direction is a first relationship, and receives the second light traveling along the second optical path among the light from the reference member generated by irradiating the reference member with the first light traveling along the second optical path from the objective optical system when a positional relationship between the mounting device and the head in the fir...

Claims

1. A movement error calculation system for calculating a movement error occurring in the movement of at least one of a mounting device for mounting a workpiece and a machining head of a machine tool that machines the workpiece with a tool detachably attached to a spindle of the machining head while moving the mounting device and / or the machining head, a reference member different from the workpiece placed on the placement device; an optical detection device that includes an objective optical system that irradiates a first light toward the reference member, and a detector that receives, via the objective optical system, a second light that travels along an optical path of the first light among the light from the reference member that is generated by the irradiation of the first light, and is attached to the spindle instead of the tool; a calculation unit that calculates the movement error based on the detection result by the photodetector; A movement error calculation system comprising:

2. the detector receives interference light between a portion of the first light and at least a portion of the second light; The calculation unit calculates the movement error based on the detection result of the interference light. The movement error calculation system according to claim 1 .

3. The main shaft is rotatable around a rotation axis, The optical axis of the objective optical system and the rotation axis are coaxial. The movement error calculation system according to claim 1 or 2.

4. the light detection device further includes a focusing optical system that is provided in an optical path between the objective optical system and the detector and forms a focusing point of the first light at a focal position on the detector side of the objective optical system, The first light emitted from the light detection device is parallel light. The movement error calculation system according to claim 1 .

5. the optical measurement device further includes an insertion / removal device that inserts and removes the focusing optical system into and from the optical path, When the condensing optical system is inserted into the optical path, the first light emitted from the objective optical system becomes parallel light, and when the condensing optical system is removed from the optical path, the first light emitted from the objective optical system becomes convergent light. The movement error calculation system according to claim 4 .

6. The light detection device further includes a traveling direction changing member that can change the traveling direction of the first light toward the objective optical system so that the irradiation position of the first light on the reference member changes. The movement error calculation system according to any one of claims 1 to 5.

7. the first light, which is propagated in a first direction by the propagating direction changing member and is incident on the objective optical system, is propagated along a first optical path and is irradiated onto a first position of the reference member; the second light traveling along the first optical path from the first position generated by the first light irradiated at the first position is incident on the detector; the first light travels in a second traveling direction different from the first traveling direction by the traveling direction changing member and is incident on the objective optical system, travels along a second optical path different from the first optical path, and is irradiated onto a second position different from the first position of the reference member, the second light traveling along the second optical path from the second position generated by the first light irradiated to the second position is incident on the detector; The calculation unit calculates the movement error based on the detection results of the light detection device at each of the first position and the second position. The movement error calculation system according to claim 6 .

8. when the first light is irradiated from the objective optical system to the first position of the reference member, the objective optical system is located at a third position; When the first light is irradiated from the objective optical system to the second position on the reference member, the objective optical system is positioned at the third position. The movement error calculation system according to claim 7 .

9. The light detection device further includes a deflection member that deflects the first light from the objective optical system toward the reference member. The movement error calculation system according to any one of claims 1 to 8.

10. The calculation unit calculates a position of at least a part of the reference member based on a detection result of the interference light, and calculates the movement error based on the calculation result of the position. The movement error calculation system according to claim 2 or any one of claims 3 to 7 dependent on claim 2.

11. the reference member includes a first region, a second region having a different characteristic from that of the first region, a third region, a fourth region having a different characteristic from that of the third region, a fifth region, and a sixth region having a different characteristic from that of the fifth region; The calculation unit calculates the movement error based on the position of a first boundary extending in a first direction and being a boundary between the first region and the second region, the position of a second boundary extending in a second direction intersecting with the first direction and being a boundary between the third region and the fourth region, and the position of a third boundary extending in a third direction intersecting with the second direction and being a boundary between the fifth region and the sixth region. The movement error calculation system according to any one of claims 7 to 10.

12. The first light is pulsed light including frequency components arranged at equal intervals on a frequency axis. The movement error calculation system according to any one of claims 1 to 11.

13. At least one of the mounting device and the processing head is movable along a first direction, The calculation unit calculates, based on a detection result by the light detection device, a movement error in a second direction and a movement error in a third direction different from the second direction that occur in movement of at least one of the mounting device and the processing head when at least one of the mounting device and the processing head moves along the first direction. The movement error calculation system according to any one of claims 1 to 12.

14. the first direction is a linear direction, the second direction is one of a linear direction that is the same as the first direction or that intersects with the first direction, and a rotational direction about an axis along the first direction or an axis that intersects with the first direction as a rotation axis, The third direction is a linear direction that is the same as the first direction or intersects with the first direction, or a rotational direction about an axis along the first direction or an axis intersecting with the first direction as a rotation axis. The movement error calculation system according to claim 13 .

15. the first direction is a rotation direction about a first axis, the second direction is one of a linear direction along the first axis or a linear direction intersecting the first axis, and a rotational direction about the first axis or a second axis intersecting the first axis, The third direction is another direction among a linear direction along the first axis or a linear direction intersecting the first axis and a rotational direction about the first axis or a second axis intersecting the first axis. The movement error calculation system according to claim 13 .

16. At least one of the mounting device and the processing head is movable along a first direction, The calculation unit calculates, based on a detection result by the light detection device, a movement error in a second direction, a movement error in a third direction different from the second direction, a movement error in a fourth direction different from the second to third direction, a movement error in a fifth direction different from the second to fourth direction, a movement error in a sixth direction different from the second to fifth direction, and a movement error in a seventh direction different from the second to sixth direction, which occur in movement of at least one of the mounting device and the processing head when at least one of the mounting device and the processing head moves along a first direction. The movement error calculation system according to any one of claims 1 to 15.

17. the detector receives the second light traveling along the first optical path among the light from the reference member generated by irradiating the reference member with the first light traveling along the first optical path from the objective optical system when the positional relationship between the mounting device and the processing head in the first direction is a first relationship, and receives the second light traveling along the second optical path among the light from the reference member generated by irradiating the reference member with the first light traveling along the second optical path from the objective optical system when the positional relationship between the mounting device and the processing head in the first direction is a second relationship different from the first relationship, The calculation unit calculates the movement error based on the detection results of the light detection device in each of the first positional relationship and the second positional relationship. The movement error calculation system according to any one of claims 13 to 16.

18. The first direction includes a direction along an optical path of the first light emitted from the objective optical system. The movement error calculation system according to any one of claims 13 to 17.

19. The first direction includes a direction intersecting an optical path of the first light emitted from the objective optical system. The movement error calculation system according to any one of claims 13 to 18.

20. the detector receives the second light traveling along the first optical path among light from a first portion of the reference member generated by irradiating the reference member with the first light traveling along the first optical path from the objective optical system when a positional relationship between the mounting device and the processing head in a direction intersecting the optical path of the first light is a first relationship; and receives the second light traveling along the second optical path among light from a second portion of the reference member that partially overlaps with the first portion, generated by irradiating the reference member with the first light traveling along the second optical path from the objective optical system when a positional relationship between the mounting device and the processing head in a direction intersecting the optical path of the first light is a second relationship different from the first relationship. The calculation unit calculates the movement error based on the detection results of the light detection device in each of the first portion and the second portion.

20. The movement error calculation system according to claim 19.

21. The reference member has a grid pattern formed thereon. The movement error calculation system according to any one of claims 1 to 20.

22. The detector detects (i) the second light traveling along the first optical path among the light from the first measurement target region generated by irradiating a first measurement target region of the grating pattern with the first light traveling along a first optical path from the objective optical system, (ii) the second light traveling along the second optical path among the light from the second measurement target region generated by irradiating a second measurement target region of the grating pattern with the first light traveling along a second optical path different from the first optical path from the objective optical system, and (iii) the first light traveling along a third optical path different from the first to second optical paths from the objective optical system to a third measurement target region of the grating pattern. (iv) the second light traveling along the fourth optical path out of the light from the fourth measurement target area generated by irradiating a fourth measurement target area of ​​the grating pattern from the objective optical system with the first light traveling along a fourth optical path different from the first to third optical paths, and (iii) the second light traveling along the fifth optical path out of the light from the fifth measurement target area generated by irradiating a fifth measurement target area of ​​the grating pattern from the objective optical system with the first light traveling along a fifth optical path different from the first to fourth optical paths, The calculation unit calculates the movement error based on the detection results of the photodetector at the first to fifth measurement target portions. The movement error calculation system according to claim 21.

23. The reference member includes a polyhedron.

23. The movement error calculation system according to any one of claims 1 to 22.

24. the polyhedron includes a first plane, a second plane having a normal oriented in a direction different from the normal of the first plane, and a third plane having a normal oriented in a direction different from the normals of the first and second planes; The detector receives: (i) the second light traveling along the first optical path among light from at least a part of the first plane generated by irradiating the first plane with the first light traveling along a first optical path from the objective optical system; (ii) the second light traveling along the second optical path among light from at least a part of the second plane generated by irradiating the second plane with the first light traveling along a second optical path different from the first optical path from the objective optical system; and (iii) the second light traveling along the third optical path among light from at least a part of the third plane generated by irradiating the third plane with the first light traveling along a third optical path different from the first to second optical paths from the objective optical system; The calculation unit calculates the movement error based on the detection results of the photodetector on the first to third planes.

24. The movement error calculation system according to claim 23.

25. the reference member includes a reflecting member that reflects the first light from the photodetector that is incident at a first position and emits the second light toward the photodetector, and that reflects the first light from the photodetector that is incident at a second position different from the first position and emits the second light toward the photodetector; The optical path length of the optical path from the first position to the position where the optical beam is emitted from the reference member via the reflecting member is different from the optical path length of the optical path from the second position to the position where the optical beam is emitted from the reference member via the reflecting member.

25. The movement error calculation system according to any one of claims 1 to 24.

26. The detector receives (i) the second light traveling along the first optical path among the light from the reflecting member generated by irradiating the reflecting member with the first light traveling along a first optical path from the objective optical system, and (ii) the second light traveling along the second optical path among the light from the reflecting member generated by irradiating the reflecting member with the first light traveling along a second optical path different from the first optical path from the objective optical system, The calculation unit calculates the movement error based on the detection result of the light detection device on the reflecting member.

26. The movement error calculation system according to claim 25.

27. A movement error calculation system according to any one of claims 1 to 26; The processing head; the placement device; a drive device that moves at least one of the processing head and the placement device; A machine tool equipped with:

28. A calculation device for calculating a movement error occurring in the movement of at least one of a mounting device capable of mounting a workpiece and a head capable of attaching a processing unit for processing the workpiece, The head includes an objective optical system that irradiates a first light toward a reference member placed on the mounting device, and a detector that receives, via the objective optical system, a second light from the reference member that is generated by the irradiation of the first light, and a calculation unit that calculates the movement error based on a detection result by a light detection device attached to the head. Calculation device.

29. Irradiating a first light from an objective optical system of a light detection device attached to a head on which a processing section for processing the workpiece can be attached, toward a reference member placed on a mounting device; receiving second light from the reference member generated by the irradiation of the first light via the objective optical system using a detector of the light detection device; calibrating information used to control the movement of at least one of the mounting device and the head based on the detection result by the light detection device; A calibration method including:

30. an objective optical system; a measurement unit that irradiates a first light toward an object via the objective optical system and receives a second light from the object that is generated by the irradiation of the first light via the objective optical system; a focusing optical system that is provided in an optical path between the objective optical system and the measurement unit and forms a focusing point of the first light at a focal position of the objective optical system on the measurement unit side; a calculation unit that measures at least a part of the object based on the light reception result by the measurement unit; An optical measurement device comprising:

31. A calculation device for calculating a movement error occurring in the movement of at least one of a mounting device capable of mounting a workpiece and a head capable of attaching a processing unit for processing the workpiece, an objective optical system that irradiates a first light toward a reference member placed on the mounting device; a calculation unit that receives, via the objective optical system, a second light from the reference member that is generated by the irradiation of the first light, and calculates the movement error based on a detection result by a light detection device attached to the head; Calculation device.

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