Non-contact shape measuring machine and position adjusting method

Abstract

To provide a non-contact shape measuring machine and a position adjusting method capable of bringing one of a sensor head and a measurement surface close to the other at a low cost and with high accuracy.SOLUTION: The non-contact shape measuring machine includes: a sensor head 20; a light receiving sensor 36 in which an incident position of reflected light LA on a light receiving surface 36a changes according to a distance between the sensor head 20 and a measurement surface Wa; a distance measuring unit 44 which measures the distance based on the incident position of the reflected light LA on the light receiving surface Wa; and a moving mechanism (C-axis moving mechanism) 16 which moves the other toward and away from one of the sensor head 20 and the measurement surface Wa along a moving axis (C-axis 14). A measurement range WR is predetermined at a position separated from the sensor head 20 in an emission direction of measurement light L, and the light receiving surface Wa has a size capable of receiving the reflected light LA even when the other is moved toward the one up to a position where the measurement surface Wa is included within a proximity range SR by the moving mechanism.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a non-contact shape measuring instrument that measures the shape of a measurement surface in a non-contact manner, and a position adjustment method used in this non-contact shape measuring instrument. [Background technology]

[0002] There is known a surface shape measuring machine that performs shape measurement such as the contour shape and surface roughness of a measurement surface of a workpiece (object to be measured). In such a surface shape measuring machine, a contactor is brought into contact with the measurement surface and the workpiece is moved relatively in the horizontal direction, and the contactor traces the measurement surface while detecting the displacement caused by the oscillation of the contactor with a sensor head, and the surface shape of the measurement surface is measured based on the displacement detection signal output from the sensor head (see Patent Document 1).

[0003] In recent years, a non-contact shape measuring machine has been well known as a surface shape measuring machine that performs shape measurement of a measurement surface by moving a sensor head capable of measuring the distance to the measurement surface without contacting it with a contactor and a workpiece in a horizontal direction relative to each other instead of bringing a contactor into contact with the measurement surface (see Patent Document 2). The sensor head for non-contact measurement measures the distance to the measurement surface using, for example, triangulation. Specifically, the sensor head emits measurement light toward the measurement surface, and the reflected light reflected by the measurement surface is received by a light receiving sensor of the sensor head. At this time, the incident position of the reflected light on the light receiving surface of the light receiving sensor changes depending on the distance between the sensor head and the measurement surface, so that the distance between the sensor head and the measurement surface can be measured based on the incident position of the reflected light on the light receiving surface. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2017-161548 A [Patent Document 2] JP 2011-196763 A Summary of the Invention [Problem to be solved by the invention]

[0005] 20 is an explanatory diagram for explaining the adjustment of the height position in the Z direction of the sensor head 100 before performing non-contact measurement of the measurement surface Wa of the workpiece W with the non-contact shape measuring machine. Note that, among the mutually orthogonal XYZ directions in the figure, the XY direction is a direction parallel to the horizontal direction, and the Z direction is an up-down direction perpendicular to the horizontal direction. The X direction is the movement direction (scanning direction) of the sensor head 100, and is the emission direction of the measurement light L emitted from the sensor head 100 from the lower side in the Z direction.

[0006] 20, the measurement range WR in which the shape of the measurement surface Wa can be measured when the sensor head 100 is moved in the X direction is spaced downward in the Z direction from the sensor head 100 when viewed from the Y direction. Therefore, as shown by the reference symbol XXA in Fig. 20, when measuring the shape of the measurement surface Wa including the recess 102, if the position of the sensor head 100 in the Z direction is adjusted so that the measurement surface Wa is located at the center position of the measurement range WR in the Z direction, the lowest point of the recess 102 will not be included in the measurement range WR.

[0007] Therefore, as shown by symbol XXB in Figure 20, the sensor head 100 is pressed toward the measurement surface Wa so that the lowest point of the recess 102 is included in the measurement range WR, and the Z-direction position adjustment of the sensor head 100 is performed to bring the sensor head 100 as close as possible to the measurement surface Wa.

[0008] When performing such Z-direction position adjustment of the sensor head 100, It is required to prevent damage to the sensor head 100 and the workpiece W by avoiding collision and contact of the sensor head 100 with the measurement surface Wa of the workpiece W. For this reason, a method is known in which a piezoelectric sensor is provided on the underside of the sensor head 100, and the sensor head 100 is lowered downward in the Z direction until it comes into contact with the measurement surface Wa based on a signal output from the piezoelectric sensor. Also, instead of providing a piezoelectric sensor on the underside of the sensor head 100, a method is known in which a distance measuring sensor that measures the distance to the measurement surface Wa is separately provided on the sensor head 100, and the sensor head 100 is brought as close as possible to the measurement surface Wa based on the measurement result of the distance measuring sensor.

[0009] However, in the method of providing a piezoelectric sensor on the underside of the sensor head 100, the sensor head 100 cannot be brought close to the measurement surface Wa at a distance (working distance) shorter than the thickness of the piezoelectric sensor. There is also the problem that it takes time to manage the wiring extending from the piezoelectric sensor. Furthermore, since the piezoelectric sensor ends up coming into contact with the measurement surface Wa, damage to the sensor head 100 and the measurement surface Wa (workpiece W) cannot be reduced to zero. Furthermore, since the piezoelectric sensor has a finite size, the working distance is effectively reduced. Furthermore, the wiring of the piezoelectric sensor is prone to picking up vibrations, which can cause measurement noise.

[0010] In addition, in the method of separately providing a distance measuring sensor in the sensor head 100, if a low-cost sensor (e.g., an ultrasonic sensor) is used as the distance measuring sensor, the measurement accuracy of the distance measuring sensor is low, so the sensor head 100 cannot be brought as close as possible to the measurement surface Wa. Conversely, if a high-precision sensor is used as the distance measuring sensor, the manufacturing cost increases. Furthermore, since the measurement axis of the sensor head 100 and the measurement axis of the distance measuring sensor are different, when the measurement surface Wa has an uneven shape, it is difficult to adjust the Z-direction position of the sensor head 100 so that the lowest point of the recess 102 is included in the measurement range WR. Furthermore, since the measurement axis of the distance measuring sensor is different from the measurement axis of the sensor head 100, it cannot be used when the workpiece W is small, for example.

[0011] The present invention has been made in view of such circumstances, and an object thereof is to provide a non-contact shape measuring machine capable of approaching one of a sensor head and a measurement surface to the other at low cost and with high accuracy, and a position adjustment method used in this non-contact shape measuring machine.

Means for Solving the Problems

[0012] The non-contact shape measuring machine for achieving the object of the present invention includes a sensor head that emits measurement light toward a measurement surface and receives reflected light of the measurement light reflected by the measurement surface, and a light receiving sensor having a light receiving surface that receives the reflected light incident on the sensor head, and the light receiving sensor is such that the incident position of the reflected light on the light receiving surface changes according to the distance between the sensor head and the measurement surface, a distance measuring unit that measures the distance based on the incident position of the reflected light on the light receiving surface, and a moving mechanism that approaches and separates one of the sensor head and the measurement surface along a predetermined moving axis, and a measurement range for performing distance measurement in the emission direction is predetermined at a position separated from the emission direction of the measurement light from the sensor head. When the range between the sensor head and the measurement range is defined as a proximity range, the light receiving surface has a size capable of receiving the reflected light even when the other is approached by the moving mechanism to a position where the measurement surface is included within the proximity range.

[0013] According to this non-contact shape measuring machine, by causing a part of the light receiving sensor to function as a proximity sensor, it is possible to detect the approach of one of the sensor head and the measurement surface to the other.

[0014] In the non-contact shape measuring machine according to another aspect of the present invention, reflected light reflected in a direction different from the incident direction of the measurement light on the measurement surface enters the sensor head.

[0015] In the non-contact shape measuring machine according to another aspect of the present invention, the measurement light emitted from the sensor head and the reflected light incident on the sensor head are coaxial.

[0016] A non-contact shape measuring machine according to another aspect of the present invention includes a position adjustment unit that drives a movement mechanism to bring one object closer to the other object, and a movement amount calculation unit that calculates a movement amount of the other object required to bring the other object closest to the one object within a range in which the measurement range includes the measurement surface after the measurement surface reaches the measurement range while the other object is approaching the one object, based on the result of reception of reflected light by the light receiving sensor, by driving the movement mechanism to bring the other object closer to the one object by the movement amount. This makes it possible to automatically bring the sensor head as close to the measurement surface as possible.

[0017] In a non-contact shape measuring instrument according to another aspect of the present invention, the position adjustment unit stops driving the movement mechanism when the light receiving sensor is unable to receive the reflected light after the measurement surface has reached the measurement range, thereby making it possible to prevent contact between the sensor head and the measurement surface.

[0018] In a non-contact shape measuring instrument according to another aspect of the present invention, a voltage value of a light receiving signal of reflected light output from a light receiving sensor varies depending on the incident position of the reflected light on the light receiving surface, and a proximity determination unit is provided for determining whether one of the measurement surfaces has approached the other to a position included in the proximity range based on the voltage value of the light receiving signal output from the light receiving sensor. This makes it possible to detect the approach of one of the sensor head and the measurement surface to the other based on the voltage value of the light receiving signal.

[0019] In a non-contact shape measuring instrument according to another aspect of the present invention, the movement axis is parallel to the vertical direction.

[0020] A position adjustment method for achieving the object of the present invention is a position adjustment method for adjusting the position of the other side along the movement axis in the above-mentioned non-contact shape measuring machine, and includes a first approaching step of bringing the other side closer to the one side by the movement mechanism, a first stopping step of stopping the first approaching step at a position where the measurement surface is included in the measurement range based on the result of receiving reflected light by the light receiving sensor during the first approaching step, a second approaching step of bringing the other side further closer to the one side by the movement mechanism after the first stopping step, a signal outputting step of outputting a approaching signal indicating the approach of the other side to the one side when the other side approaches the one side to a position where the measurement surface is included in the proximity range based on the result of receiving reflected light by the light receiving sensor during the second approaching step, a separating step of moving the other side away from the one side by the movement mechanism when the signal outputting step is executed, and a second stopping step of stopping the separating step when the measurement surface reaches the measurement range based on the result of receiving reflected light by the light receiving sensor during the separating step.

[0021] According to this position adjustment method, the sensor head can be brought as close as possible to the measurement surface.

[0022] In a non-contact shape measuring instrument according to another aspect of the present invention, in the first approaching step, the other is moved faster than in the second approaching step and the separating step, thereby making it possible to shorten the time required for position adjustment. Effect of the Invention

[0023] The present invention enables one of the sensor head and the measurement surface to be brought closer to the other at low cost and with high accuracy. [Brief description of the drawings]

[0024] [Figure 1] 1 is a schematic diagram of a surface profile measuring instrument according to a first embodiment; [Diagram 2] FIG. 2 is a schematic diagram of a sensor head according to the first embodiment. [Diagram 3] FIG. 4 is an explanatory diagram for explaining a measurement range of a sensor head. [Figure 4]11 is an explanatory diagram for explaining a head position range showing a range of height positions in the Z direction of the sensor head that is allowable when measuring the shape of a measurement surface. FIG. [Diagram 5] 5 is a diagram showing a state in which the sensor head is brought closer to the measurement surface beyond the head position range shown in FIG. 4. [Figure 6] 4 is an explanatory diagram for explaining a light receiving sensor of the sensor head. FIG. [Figure 7] FIG. 2 is a functional block diagram of a control device according to the first embodiment. [Figure 8] 5 is a flowchart showing a flow of a shape measurement process of a measurement surface of a workpiece by the surface shape measuring machine of the first embodiment. [Figure 9] 9 is a flowchart showing the flow of a process for adjusting the height position of the sensor head in FIG. 8. [Figure 10] 11 is an explanatory diagram for explaining a height position adjustment process of a sensor head. FIG. [Figure 11] FIG. 11 is a functional block diagram of a control device of a surface profile measuring machine according to a second embodiment. [Figure 12] 11 is an explanatory diagram for explaining a movement amount calculated by a movement amount calculation unit; FIG. [Figure 13] 10 is a flowchart showing the flow of a height position adjustment process of a sensor head in a surface profile measuring instrument according to a second embodiment. [Figure 14] 13 is an explanatory diagram for explaining a height position adjustment process of a sensor head in the surface profile measuring instrument according to the second embodiment. FIG. [Figure 15] 15 is an explanatory diagram for explaining the reason why the movement of the sensor head is stopped in step S17A of FIG. 14. FIG. [Figure 16] 2 is an explanatory diagram for explaining a first light-receiving region and a second light-receiving region on a light-receiving surface of a light-receiving sensor that receives reflected light incident on a color confocal type sensor head. FIG. [Figure 17] 17 is an explanatory diagram for explaining in detail the second light receiving region described in FIG. 16. FIG. [Figure 18] 13 is an explanatory diagram for explaining a method of approach determination by the approach determiner of the fourth embodiment. FIG. [Figure 19]10A to 10C are explanatory diagrams for explaining modified examples of the surface shape measuring instruments according to the above embodiments. [Figure 20] 11 is an explanatory diagram for explaining adjustment of the height position in the Z direction of a sensor head before performing non-contact measurement of a measurement surface of a workpiece with a non-contact shape measuring machine. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] [First embodiment] Fig. 1 is a schematic diagram of a surface profile measuring machine 10 of a first embodiment corresponding to the non-contact profile measuring machine of the present invention. As shown in Fig. 1, the surface profile measuring machine 10 performs non-contact measurement of the profile of a measurement surface Wa of a workpiece W, specifically, the contour profile or surface roughness. Of the mutually orthogonal XYZ directions in the figure, the XY directions are planes parallel to the horizontal direction, and the Z direction is an up-down direction perpendicular to the horizontal direction. The Z direction is also a direction parallel (including approximately parallel, the same applies below) to the movement axis of the present invention.

[0026] The surface profile measuring instrument 10 includes a measuring table 12, a C-axis 14, a C-axis moving mechanism 16, a holder 18, a sensor head 20, an operation unit 22, a monitor 24, and a control device 26.

[0027] The measurement table 12 is substantially flat and has an upper surface parallel to the XY plane. A workpiece W is set on the upper surface of the measurement table 12, and a C-axis 14 is also provided thereon.

[0028] The C-axis 14 corresponds to the moving axis of the present invention, and is a column extending in the Z direction (upward) from the upper surface of the measurement table 12. A holder 18 is attached to this C-axis 14 via a C-axis moving mechanism 16 so as to be freely movable in the Z direction.

[0029] The C-axis moving mechanism 16 adjusts the position of the sensor head 20 in the Z direction (adjusts the height position) by moving the holder 18 along the C-axis 14, i.e., in the Z direction. This makes it possible to adjust the distance between the sensor head 20 and the measurement surface Wa. In this case, the sensor head 20 corresponds to the "other" of the present invention, and the measurement surface Wa corresponds to the "one" of the present invention. Equivalent.

[0030] The C-axis moving mechanism 16 is a known actuator that moves the holder 18 along the C-axis 14 (Z direction). The C-axis moving mechanism 16 automatically moves the holder 18 in the Z direction under the control of a control device 26 described below, or moves the holder 18 in the Z direction in response to an operator's operation (manual movement operation) of a lift lever 22a (see FIG. 7). Note that the manual movement operation of the holder 18 may be performed using a known operating member other than the lift lever 22a.

[0031] As shown in FIG. 7, the holder 18 includes an X-axis moving mechanism 18a and an X-position detection sensor 18b. The X-axis moving mechanism 18a is a known actuator that holds the sensor head 20 movably in the X direction under the control of a control device 26 described later. By driving the X-axis moving mechanism 18a, the sensor head 20 can be moved in the X direction relative to the workpiece W (measurement surface Wa). The X-position detection sensor 18b is composed of a linear scale and its reading head (not shown), and detects the X-direction position of the sensor head 20 and outputs the detection result to the control device 26. The X-axis moving mechanism 18a and the X-position detection sensor 18b are not limited to the above-mentioned configuration, and for example, a stepping motor can be used as the drive source of the X-axis moving mechanism 18a. In this case, the X-position detection sensor 18b can detect the position based on the number of drive pulses of the stepping motor.

[0032] The sensor head 20 is a detector (distance measuring sensor) used for measuring the distance to the measurement surface Wa by triangulation (non-contact distance measurement). The sensor head 20 emits measurement light L toward the measurement surface Wa located below it in the Z direction, and receives reflected light LA ​​of the measurement light L reflected by the measurement surface Wa. Therefore, in this embodiment, the emission direction of the measurement light L in the sensor head 20 is downward in the Z direction. The configuration of the sensor head 20 will be described later (see FIG. 2). The measurement surface Wa can be scanned along the X direction with the measurement light L by moving the sensor head 20 in the X direction by the X-axis moving mechanism 18a (see FIG. 7).

[0033] The operation unit 22 uses, for example, a keyboard, a mouse, an operation panel, and operation buttons, and receives input of various operations by an operator. The operation unit 22 also includes a lift lever 22a that allows the operator to manually operate the C-axis movement mechanism 16 (see FIG. 7).

[0034] Various displays such as a known liquid crystal display are used as the monitor 24. The monitor 24 displays the shape measurement results of the measurement surface Wa by the surface profile measuring instrument 10, various setting screens of the surface profile measuring instrument 10, various operation screens of the surface profile measuring instrument 10, etc.

[0035] The C-axis moving mechanism 16, the holder 18, the sensor head 20, the operation unit 22, and the monitor 24 are connected to the control device 26. The control device 26 comprehensively controls the operation of each part of the surface profile measuring instrument 10 in response to an input operation to the operation unit 22.

[0036] Fig. 2 is a schematic diagram of the sensor head 20 of the first embodiment. As shown in Fig. 2, the sensor head 20 includes a light source 30, a light incident / exit surface 32, a lens 34, and a light receiving sensor 36. The light source 30 emits measurement light L downward in the Z direction.

[0037] The light incident / exit surface 32 is a bottom surface on the lower side in the Z direction facing the measurement surface Wa, and has a light exit window 32a and a light entrance window 32b. The light exit window 32a is formed in the light incident / exit surface 32 at a position on the lower side of the light source 30 in the Z direction, and passes the measurement light L emitted from the light source 30 and emits the measurement light L toward the measurement surface Wa. The light entrance window 32b is formed in a position shifted in the X direction from the light exit window 32a in the light incident / exit surface 32. The reflected light LA ​​reflected in a direction different from the incident direction of the measurement light L on the measurement surface Wa is incident on the light entrance window 32b.

[0038] The light entrance window 32b is formed to have a width in the X direction larger than that of the light exit window 32a in response to the fact that the incident position and incident angle of the reflected light LA ​​with respect to the light entrance / exit surface 32 change depending on the distance between the sensor head 20 and the measurement surface Wa (see FIG. 6). The light exit window 32a and the light entrance window 32b may be openings.

[0039] The lens transmits the reflected light LA ​​incident through the light entrance window 32b, and emits the reflected light LA ​​toward a light receiving surface a of the light receiving sensor .

[0040] The light receiving sensor 36 is, for example, a one-dimensional or two-dimensional imaging element of the CCD (Charge Coupled Device) type or CMOS (Complementary Metal-Oxide-Semiconductor) type, and has a light receiving surface 36a that receives the reflected light LA ​​incident from the measurement surface Wa through the light entrance window 32b and the lens 34. In the triangulation type sensor head 20, the incident position of the reflected light LA ​​on the light receiving surface 36a changes depending on the distance between the sensor head 20 and the measurement surface Wa in the emission direction of the measurement light L (here, the Z direction). This makes it possible to measure the distance between the sensor head 20 and the measurement surface Wa based on the incident position of the reflected light LA ​​on the light receiving surface 36a.

[0041] FIG. 3 is an explanatory diagram for explaining the measurement range WR of the sensor head 20. In the sensor head 20 of the triangulation method, as described above, according to the distance between the sensor head 20 and the measurement surface Wa, the incident position of the reflected light LA with respect to the light receiving surface 36a changes. For this reason, according to the size of the light receiving surface 36a, a measurement range WR in the Z direction (hereinafter simply referred to as the measurement range WR) capable of accurately measuring the distance to the measurement surface Wa is predetermined for each type of sensor head 20. This measurement range WR is defined at a position spaced downward in the Z direction with respect to the sensor head 20. For this reason, a proximity range SR, which is a range closer to the sensor head 20 side than the measurement range WR, is provided between the sensor head 20 (light input / output surface 32) and the measurement range WR.

[0042] Note that in the sensor head 20, in order to narrow the spot diameter of the measurement light L, it is common to insert a lens (not shown) between the light source 30 and the light output window 32a. However, if a lens with a short focal length is used to improve the lateral resolution of the sensor head 20, the spot diameter becomes large on the side closer to the sensor head 20. For this reason, a range that is not very suitable for measurements requiring the lateral resolution of the sensor head 20 may be assigned to the proximity range SR.

[0043] FIG. 4 is an explanatory diagram for explaining a head position range MR indicating a range of the height position of the sensor head 20 in the Z direction that is allowed during the shape measurement of the measurement surface Wa. FIG. 5 is a diagram showing a state in which the sensor head 20 is brought closer to the measurement surface Wa beyond the head position range MR shown in FIG. 4.

[0044] As shown by reference numerals 4A and 4B in FIG. 4, during the shape measurement of the measurement surface Wa, the height position of the sensor head 20 in the Z direction is adjusted by the C-axis movement mechanism 16 so that the measurement surface Wa is included within the measurement range WR of the sensor head 20, that is, between the lower limit (see reference numeral 4A in FIG. 4) and the upper limit (see reference numeral 4B in FIG. 4) in the Z direction thereof. Specifically, the height position of the sensor head 20 (here, the light input / output surface 32) in the Z direction is adjusted by the C-axis movement mechanism 16 within a head position range MR, which is a position range in which the measurement surface Wa is included within the measurement range WR.

[0045] Here, as shown in Fig. 20, a recess 102 may be formed on the measurement surface Wa. For this reason, when measuring the shape of the measurement surface Wa, it is preferable to move the sensor head 20 as close as possible to the measurement surface Wa up to a height position (hereinafter referred to as target height position H1) where the upper limit of the measurement range WR reaches the measurement surface Wa as viewed from the Y direction side, as shown by reference numeral 4B in Fig. 4.

[0046] In this embodiment, in order to bring the sensor head 20 as close as possible to the measurement surface Wa, the sensor head 20 is first brought close to the measurement surface Wa to a position where the measurement surface Wa is included within the proximity range SR as shown in Fig. 5. Next, the sensor head 20 is moved upward in the Z direction away from the measurement surface Wa, thereby adjusting the position of the sensor head 20 to the target height position H1 shown by reference symbol 4B in Fig. 4.

[0047] When the sensor head 20 is brought close to the measurement surface Wa to a position where the measurement surface Wa is included within the proximity range SR in this way, it is necessary to be able to detect the measurement surface Wa even within the proximity range SR in order to avoid contact of the sensor head 20 with the measurement surface Wa. In this case, if a piezoelectric sensor or a distance measuring sensor is provided in the sensor head 20, problems arise in terms of accuracy and cost.

[0048] Therefore, in this embodiment, the size of the light receiving sensor 36 (light receiving surface 36a) of the sensor head 20 is adjusted (enlarged compared to the conventional size) so that the measurement surface Wa can be detected even within the proximity range SR (see FIG. 6).

[0049] 6 is an explanatory diagram for explaining the light receiving sensor 36 of the sensor head 20. Note that symbols A1 and A2 in the drawing indicate the measurement surface Wa located within the measurement range WR, and symbol B in the drawing indicates the measurement surface Wa located within the proximity range SR.

[0050] 6, the light receiving surface 36a of the light receiving sensor 36 has a size capable of receiving reflected light LA ​​reflected by a measurement surface Wa (see reference symbols A1 and A2) within the measurement range WR as well as reflected light LA ​​reflected by a measurement surface Wa (see reference symbol B) within the proximity range SR. Therefore, the light receiving surface 36a includes a first light receiving area E1 that receives reflected light LA ​​from the measurement surface Wa within the measurement range WR and a second light receiving area E2 that receives reflected light LA ​​from the measurement surface Wa within the proximity range SR. This second light receiving area E2 functions as a proximity sensor capable of detecting the measurement surface Wa within the proximity range SR.

[0051] In this way, by allocating a portion of the light receiving sensor 36 (light receiving surface 36a) as a proximity sensor, the sensor head 20 is able to detect when the sensor head 20 has approached the measurement surface Wa to a position where the measurement surface Wa is included within the proximity range SR, without the need for a piezoelectric sensor, a distance measuring sensor, or the like.

[0052] Fig. 7 is a functional block diagram of the control device 26 of the first embodiment. As shown in Fig. 7, the control device 26 includes an arithmetic circuit configured with various processors and memories. The various processors include a central processing unit (CPU), a graphics processing unit (GPU), an application specific integrated circuit (ASIC), and a programmable logic device (e.g., simple programmable logic devices (SPLD), complex programmable logic devices (CPLD), and field programmable gate arrays (FPGA)). The various functions of the control device 26 may be realized by one processor or by multiple processors of the same or different types.

[0053] The control device 26 functions as a height position adjustment unit 40, an approach determination unit 42, an adjustment end determination unit 43, a shape measurement control unit 44, a distance measurement unit 46, and a shape calculation unit 48 by executing a control program read out from a memory unit not shown.

[0054] The height position adjustment unit 40 operates before starting measurement of the shape of the measurement surface Wa, and executes part of a height position adjustment process to adjust the height position of the sensor head 20 in the Z direction to a target height position H1 (see symbol 4B in Figure 4).

[0055] Here, the height position adjustment process of the sensor head 20 is roughly divided into a first position adjustment process and a second position adjustment process. The first position adjustment process is a process of moving the sensor head 20 downward in the Z direction from an initial position separated upward from the measurement surface Wa in the Z direction to a position where the measurement surface Wa is included in the measurement range WR. The second position adjustment process is a process of moving the sensor head 20 further downward in the Z direction to a position where the measurement surface Wa is included in the proximity range SR. The third position adjustment process is a process of moving the sensor head 20 upward in the Z direction to the target height position H1. The height position adjustment unit 40 of the first embodiment drives the C-axis moving mechanism 16 to perform only the first position adjustment process. The second position adjustment process and the third position adjustment process are performed by the operator operating the lift lever 22a to drive the C-axis moving mechanism 16, that is, by a manual moving operation.

[0056] The height position adjustment unit 40 operates when a start operation for adjusting the height position of the sensor head 20 is performed on the operation unit 22, and executes the first position adjustment process. The height position adjustment unit 40 drives the C-axis movement mechanism 16 to move the sensor head 20 downward in the Z direction along the C-axis 14. Then, based on the light reception result (light reception position) of the reflected light LA ​​at the first light reception area E1 of the light reception surface 36a of the light receiving sensor 36, when the sensor head 20 reaches a position that includes the measurement surface Wa within the measurement range WR, for example, when the center position in the Z direction of the measurement range WR reaches the measurement surface Wa, the height position adjustment unit 40 stops the movement of the sensor head 20 by the C-axis movement mechanism 16. This completes the first position adjustment process. Thereafter, the second position adjustment process and the third position adjustment process are executed by manual movement operation by the operator (see FIG. 9).

[0057] The movement of the sensor head 20 in the first position adjustment process is executed faster than the movement of the sensor head 20 in the second position adjustment process and the third position adjustment process executed by a manual movement operation.

[0058] The approach determination unit 42 is connected to the sensor head 20 (light receiving sensor 36) via, for example, a known communication line (Ethernet, RS232C, etc.). The approach determination unit 42 operates when the second position adjustment process is started by a manual movement operation by the operator, and determines whether or not the sensor head 20 has approached the measurement surface Wa to a position where the measurement surface Wa is included in the proximity range SR during the execution of this second position adjustment process.

[0059] Specifically, when the sensor head 20 approaches the measurement surface Wa to a position where the measurement surface Wa is included within the proximity range SR, the reflected light LA ​​is incident on the second light receiving area E2 of the light receiving surface 36a, and a light receiving signal of the reflected light LA ​​is output from this second light receiving area E2. Therefore, the light receiving signal of the reflected light LA ​​output from the second light receiving area E2 is a near signal indicating that the sensor head 20 has approached the measurement surface Wa to a position where the measurement surface Wa is included within the proximity range SR. Therefore, the approach determination unit 42 is capable of making an approach determination (hereinafter, abbreviated as approach determination) for determining whether or not the sensor head 20 is in an approach state where the sensor head 20 has approached the measurement surface Wa to a position where the measurement surface Wa is included within the proximity range SR, based on whether or not an approach signal has been output from the light receiving sensor 36.

[0060] Furthermore, when the approach determination unit 42 determines that the sensor head 20 is in the “approaching state” in the approach determination, the approach determination unit 42 displays approach information indicating that on the monitor 24. This allows the operator to know that the sensor head 20 has approached the measurement surface Wa, i.e., that the second position adjustment process has been completed.

[0061] The adjustment end determination unit 43 operates when the third position adjustment process is started by a manual movement operation by the operator, and determines whether or not the sensor head 20 has reached the target height position H1 during execution of this third position adjustment process. When the measurement surface Wa reaches the upper limit of the measurement range WR from the proximity range SR during the third position adjustment process, the reflected light LA ​​is incident on the first light receiving area E1 of the light receiving surface 36a. In this case, the output of the approach signal from the light receiving sensor 36 stops, and a light receiving signal of the reflected light LA ​​is output from the first light receiving area E1. Therefore, the adjustment end determination unit 43 determines whether or not the output of the approach signal from the light receiving sensor 36 has stopped (the reception of the reflected light LA ​​from the first light receiving area E1 has stopped). Based on whether or not an optical signal is output, it is possible to make an adjustment end judgment (hereinafter, abbreviated as adjustment end judgment) for judging whether or not the sensor head 20 has reached the target height position H1.

[0062] Furthermore, when the adjustment completion determination unit 43 determines in the adjustment completion determination that "the sensor head 20 has reached the target height position H1," it displays adjustment completion information indicating that on the monitor 24. This allows the operator to know that the sensor head 20 has reached the target height position H1, i.e., that all height position adjustments of the sensor head 20 have been completed.

[0063] The shape measurement control unit 44 operates when an operation to start shape measurement of the measurement surface Wa is executed on the operation unit 22 after the position of the sensor head 20 is adjusted to the target height position H1. The shape measurement control unit 44 drives the X-axis moving mechanism 18a of the holder 18 to move the sensor head 20 in the X direction, and also starts detection of the X-direction position of the sensor head 20 by the X-position detection sensor 18b. As a result, the measurement surface Wa is scanned along the X direction by the measurement light L emitted from the sensor head 20, that is, the shape measurement of the measurement surface Wa is executed.

[0064] When the shape measurement of the measurement surface Wa is started, the distance measurement unit 46 continuously measures the distance from the sensor head 20 to the measurement surface Wa (the irradiation position of the measurement light L) based on the light receiving position of the reflected light LA ​​incident on the first light receiving area E1 of the light receiving surface 36a, and continuously outputs the distance measurement results to the shape calculation unit 48. Note that the distance measurement by the distance measurement unit 46 is performed in synchronization with the detection of the X-direction position of the sensor head 20 by the X-position detection sensor 18b.

[0065] The shape calculation unit 48 calculates various shapes of the measurement surface Wa using a known method based on the distance measurement results by the distance measurement unit 46 and the X-direction position detection results of the sensor head 20 by the X-position detection sensor 18b, which are executed in synchronization with each other.

[0066] When the shape measurement of the measurement surface Wa is completed, the operator operates the lift lever 22a to drive the C-axis movement mechanism 16 to move (retract) the sensor head 20 upward in the Z direction along the C-axis 14, thereby moving it away from the measurement surface Wa. This movement continues until the reflected light LA ​​is no longer received by the first light receiving area E1 of the light receiving surface 36a, that is, until the measurement surface Wa moves out of the measurement range WR. The movement of the sensor head 20 in this case can be performed faster than the movement of the sensor head 20 in the second position adjustment process and the third position adjustment process.

[0067] [Operation of the first embodiment] Fig. 8 is a flowchart showing the flow of a shape measurement process of the measurement surface Wa of the workpiece W by the surface shape measuring machine 10 of the first embodiment having the above-mentioned configuration. Fig. 9 is a flowchart showing the flow of a height position adjustment process of the sensor head 20 in Fig. 8, which relates to the position adjustment method of the present invention. Fig. 10 is an explanatory diagram for explaining the height position adjustment process of the sensor head 20.

[0068] As shown in FIG. 8, after an operator sets a workpiece W on the upper surface of the measurement table 12, first, a height position adjustment process is executed to adjust the height position of the sensor head 20 in the Z direction to a target height position H1 (step S10).

[0069] 9 and 10, in response to an operator's operation to start height position adjustment on the operation unit 22, the height position adjustment unit 40 drives the C-axis movement mechanism 16 to move the sensor head 20 downward in the Z direction along the C-axis 14 at high speed (step S11, see reference symbol XA in FIG. 10). This causes the sensor head 20 to approach the measurement surface Wa at high speed. Note that step S11 corresponds to the first approach step of the present invention.

[0070] When the reflected light LA ​​is not received by the first light receiving area E1 of the light receiving surface 36a, that is, when the height position adjustment unit 40 moves the sensor head to a position where the measurement surface Wa is included in the measurement range WR, If the sensor head 20 is not approaching the measurement surface Wa, the sensor head 20 continues to move downward in the Z direction at high speed (NO in step S12).

[0071] When the sensor head 20 approaches the measurement surface Wa to a position where the measurement surface Wa is included within the measurement range WR, the reflected light LA ​​is received by the first light receiving area E1 (YES in step S12). Then, when the reflected light LA ​​is received by the first light receiving area E1, the height position adjustment unit 40 stops the movement of the sensor head 20 by the C-axis movement mechanism 16 at a position where an arbitrary position within the measurement range WR (for example, the center position in the Z direction) reaches the measurement surface Wa based on the light reception result (step S13, see symbol XB in FIG. 10). Note that step S13 corresponds to the first stopping step of the present invention. This completes the first position adjustment process of the sensor head 20.

[0072] When the first position adjustment process of the sensor head 20 is completed, the operator operates the lift lever 22a to drive the C-axis movement mechanism 16, thereby manually moving the sensor head 20 further downward in the Z direction along the C-axis 14 at low speed (step S14). Note that step S14 corresponds to the second approach step of the present invention. This starts the second position adjustment process of the sensor head 20, and the sensor head 20 moves further closer to the measurement surface Wa. At the same time, the approach determination unit 42 starts approach determination by monitoring whether or not an approach signal is output from the light receiving sensor 36 (NO in step S15).

[0073] When the sensor head 20 approaches the measurement surface Wa to a position where the measurement surface Wa is included within the proximity range SR, the reflected light LA ​​is incident on the second light receiving area E2, and an approach signal is output from the light receiving sensor 36 (YES in step S15, which corresponds to a signal output step of the present invention). As a result, the approach determination unit 42 determines the approach state as the approach state, and displays approach information indicating that on the monitor 24 (step S16).

[0074] In response to the display of the approach information on the monitor 24, the operator stops the drive of the C-axis movement mechanism 16 by the lift lever 22a, thereby stopping the movement of the sensor head 20. This causes the sensor head 20 to stop at a height position where the measurement surface Wa is included in the proximity range SR (see symbol XC in FIG. 10). This completes the second position adjustment process for the sensor head 20.

[0075] When the second position adjustment process of the sensor head 20 is completed, the operator operates the lift lever 22a to drive the C-axis moving mechanism 16, thereby manually moving the sensor head 20 upward in the Z direction along the C-axis 14 (step S17). This starts the third position adjustment process of the sensor head 20, and the sensor head 20 moves away from the measurement surface Wa (corresponding to the moving away step of the present invention). At the same time, the approach determination unit 42 starts an adjustment end determination by monitoring whether or not an approach signal is output from the light receiving sensor 36 (NO in step S18).

[0076] When the measurement surface Wa reaches the upper limit of the measurement range WR (within the measurement range WR), the reflected light LA ​​is incident on the first light receiving area E1, and the output of the approach signal from the light receiving sensor 36 stops (YES in step S18). As a result, the adjustment end determination unit 43 determines that "the sensor head 20 has reached the target height position H1" in the adjustment end determination, and displays adjustment end information on the monitor 24. In response to the display of the adjustment end information on the monitor 24, the operator stops the movement of the sensor head 20 by stopping the drive of the C-axis moving mechanism 16 by the lift lever 22a (step S19, corresponding to the second stopping step of the present invention). As a result, the position of the sensor head 20 is adjusted to the target height position H1 (see symbol XD in FIG. 10). With the above, the third position adjustment process of the sensor head 20 is completed, that is, all height position adjustment processes of the sensor head 20 are completed.

[0077] Returning to FIG. 8, after adjusting the position of the sensor head 20 to the target height position H1, the operator An operation to start the shape measurement of the measurement surface Wa is executed in the operation unit 22 (step S20). In response to this start operation, the shape measurement control unit 44 drives the X-axis moving mechanism 18a to move the sensor head 20 in the X direction, and also starts detection of the X-direction position of the sensor head 20 by the X-position detection sensor 18b, thereby starting the shape measurement of the measurement surface Wa (step S30).

[0078] When the shape measurement of the measurement surface Wa is started, the distance measurement by the distance measurement unit 46 and the detection of the X-direction position of the sensor head 20 by the X-position detection sensor 18b are synchronously and continuously performed. Then, based on these results, the shape calculation unit 48 calculates various shapes of the measurement surface Wa by a known method.

[0079] When the operator has completed the shape measurement of the measurement surface Wa, he or she operates the lift lever 22a to drive the C-axis movement mechanism 16, thereby manually moving the sensor head 20 upward in the Z direction along the C-axis 14 at high speed. This causes the sensor head 20 to move away from the measurement surface Wa at high speed (NO in steps S40 and S50). The sensor head 20 continues to move away from the measurement surface Wa until the measurement surface Wa is outside the measurement range WR (YES in step S50).

[0080] As described above, in the surface profile measuring instrument 10 of the first embodiment, the size of the light receiving surface 36a of the light receiving sensor 36 is enlarged from the conventional size, and the light receiving sensor 36 also functions as a proximity sensor, so that the measurement surface Wa within the proximity range SR can be detected without providing a piezoelectric sensor and a distance measuring sensor separately in the sensor head 20. As a result, the sensor head 20 can be brought close to the measurement surface Wa at low cost and with high accuracy. This allows the position of the sensor head 20 to be adjusted to the target height position H1 at low cost and with high accuracy.

[0081] [Second embodiment] 11 is a functional block diagram of the control device 26 of the surface profile measuring machine 10 of the second embodiment. In the surface profile measuring machine 10 of the first embodiment, part of the height position adjustment process of the sensor head 20 (second position adjustment process and third position adjustment process) is performed by a manual movement operation by an operator, but the surface profile measuring machine 10 of the second embodiment automatically performs all of the height position adjustment process of the sensor head 20.

[0082] 11, the surface profile measuring instrument 10 of the second embodiment has basically the same configuration as the surface profile measuring instrument 10 of the first embodiment, except that the function of the height position adjustment unit 40 of the control device 26 is different from that of the first embodiment, and the control device 26 functions as a movement amount calculation unit 41 instead of the adjustment end determination unit 43. For this reason, parts that are the same in function or configuration as those of the first embodiment are given the same reference numerals and their description will be omitted.

[0083] FIG. 12 is an explanatory diagram for explaining the movement amount Δh calculated by the movement amount calculation unit 41. As shown in FIG. 12, while the sensor head 20 is approaching the measurement surface Wa from the above-described initial position, after the measurement surface Wa reaches the lower limit of the measurement range WR, the movement amount calculation unit 41 calculates the movement amount Δh necessary to bring the sensor head 20 closest to the measurement surface Wa within the range where the measurement surface Wa is included in the measurement range WR. Here, "bringing the sensor head 20 closest to the measurement surface Wa within the range where the measurement surface Wa is included in the measurement range WR" means moving the sensor head 20 to the target height position H1 (see FIG. 4). Since the Z-direction distance from the sensor head 20 to the measurement range WR and the Z-direction width of the measurement range WR are known, the movement amount calculation unit 41 can calculate the movement amount Δh based on this known information.

[0084] Note that instead of causing the control device 26 to function as the movement amount calculation unit 41, the pre-calculated movement amount Δh may be stored in a storage unit (not shown).

[0085] Returning to FIG. 11, when the start operation of adjusting the height position of the sensor head 20 is executed by the operation unit 22, the height position adjustment unit 40 (corresponding to the position adjustment unit of the present invention) of the second embodiment drives the C-axis movement mechanism 16 based on the light reception result of the reflected light LA by the light reception sensor 36 and the movement amount Δh, and automatically moves the sensor head 20 to the target height position H1 (see FIG. 13 described later).

[0086] FIG. 13 is a flowchart showing the flow of the height position adjustment process of the sensor head 20 in the surface shape measuring machine 10 of the second embodiment. FIG. 14 is an explanatory diagram for explaining the height position adjustment process of the sensor head 20 in the surface shape measuring machine 10 of the second embodiment.

[0087] 13 and 14, in response to an operator's operation to start height position adjustment on the operation unit 22, the height position adjustment unit 40 drives the C-axis movement mechanism 16 to move the sensor head 20 downward in the Z direction at high speed along the C-axis 14 (step S11, see reference symbol XIVA in FIG. 14). This causes the sensor head 20 to approach the measurement surface Wa at high speed. Then, the height position adjustment unit 40 continues to move the sensor head 20 downward in the Z direction at high speed until the position where the reflected light LA ​​is received by the first light receiving area E1, that is, the position where the measurement surface Wa reaches the lower limit of the measurement range WR (NO in step S12).

[0088] When the sensor head 20 approaches the measurement surface Wa to the reference position H0 where the measurement surface Wa reaches the lower limit of the measurement range WR (YES in step S12, see reference character XIVB in FIG. 14), the reflected light LA ​​is received by the first light receiving region E1. When the reflected light LA ​​is received by the first light receiving region E1, that is, when the sensor head 20 reaches the reference position H0, the height position adjustment unit 40 acquires the calculation result of the movement amount Δh from the movement amount calculation unit 41 (step S13A). Note that the timing at which the height position adjustment unit 40 acquires the movement amount Δh is not particularly limited as long as it is before step S14A described later.

[0089] Then, the height position adjustment unit 40 drives the C-axis movement mechanism 16 to move the sensor head 20 further downward in the Z direction from the reference position H0 by a movement amount Δh at high speed (low speed movement is also possible), i.e., to move it closer to the measurement surface Wa (step S14A).

[0090] At this time, the height position adjustment unit 40 monitors whether or not the reflected light LA ​​is received by the light receiving surface 36a while the sensor head 20 is further moved downward in the Z direction by the movement amount Δh from the reference position H0. If the light receiving sensor 36 is no longer able to receive the reflected light LA ​​during this movement of the sensor head 20, the height position adjustment unit 40 stops the movement of the sensor head 20 by the C-axis movement mechanism 16 (NO in step S15A, NO in step S16A, step S17A).

[0091] FIG. 15 is an explanatory diagram for explaining the reason for stopping the movement of the sensor head 20 in step S17A of FIG. 14. As shown by symbols XVA and XVB in FIG. 15, it is difficult to precisely align the emission direction (measurement axis) of the measurement light L from the sensor head 20 with the C-axis 14 (Z direction), and this emission direction may be inclined with respect to the Z direction. In this case, as the sensor head 20 moves downward in the Z direction, the incident position of the measurement light L incident on the measurement surface Wa from the sensor head 20 changes. For this reason, if the measurement surface Wa is inclined or uneven (concave 102, etc.), the light receiving sensor 36 may not be able to receive the reflected light LA ​​during the movement of the sensor head 20 downward in the Z direction (approaching the measurement surface Wa), and the light receiving sensor 36 may lose sensitivity. As a result, if the sensor head 20 continues to move downward in the Z direction, the sensor head 20 may come into contact with the measurement surface Wa.

[0092] Therefore, in the second embodiment, the sensor head 20 is moved further from the reference position H0 by an amount Δh. If the light receiving sensor 36 loses its sensitivity while being moved downward in the Z direction, the movement of the sensor head 20 is stopped, thereby making it possible to prevent the sensor head 20 from coming into contact with the measurement surface Wa.

[0093] In addition, the height position adjustment unit 40 may stop the movement of the sensor head 20 when the approach determination unit 42 determines that the sensor head 20 is in an “approaching state” in the approach determination, i.e., when the sensor head 20 approaches the measurement surface Wa to a position where the measurement surface Wa is included within the proximity range SR.

[0094] 13 and 14, when the C-axis moving mechanism 16 has moved the sensor head 20 downward in the Z direction from the reference position H0 by the movement amount Δh, the height position adjustment unit 40 stops the movement of the sensor head 20 by the C-axis moving mechanism 16 (YES in step S15A, YES in step S16A). As a result, the position of the sensor head 20 is automatically adjusted to the target height position H1 (see symbol XIVC in FIG. 14). Note that the subsequent processing is the same as in the first embodiment (see FIG. 8), and therefore a detailed description will be omitted here.

[0095] As described above, in the surface profile measuring instrument 10 of the second embodiment, the height position adjustment of the sensor head 20 can be performed automatically, so that the position of the sensor head 20 can be adjusted to the target height position H1 more easily, more accurately, and in a shorter time than in the first embodiment.

[0096] [Third embodiment] In the surface profile measuring instrument 10 of each of the above embodiments, a triangulation type sensor head 20 is used to measure the distance between the sensor head 20 and the measurement surface Wa, but the present invention is also applicable to a surface profile measuring instrument 10 that measures the distance to the measurement surface Wa using a known color confocal type sensor head 20 (not shown). Note that components that are the same in function or configuration as those of the above embodiments are given the same reference numerals and their description is omitted.

[0097] In the color confocal sensor head 20, the wavelength of the reflected light LA ​​incident on the sensor head 20 [pinhole (optical fiber cable, etc., not shown)] changes depending on the distance between the sensor head 20 and the measurement surface Wa, and the incident position of the reflected light LA ​​incident on the light receiving surface 36a (pixel position on the light receiving surface 36a) changes depending on the wavelength of the reflected light LA. Therefore, as in each of the above embodiments, the color confocal sensor head 20 can detect the measurement surface Wa within the proximity range SR by enlarging the size of the light receiving surface 36a more than before. Note that in the color confocal sensor head 20, the measurement light L and the reflected light LA ​​are coaxial.

[0098] Fig. 16 is an explanatory diagram for explaining the first light-receiving region E1 and the second light-receiving region E2 on the light-receiving surface 36a of the light-receiving sensor 36 that receives the reflected light LA ​​incident on the color confocal sensor head 20. Note that the horizontal axis in Fig. 16 indicates the pixel position on the light-receiving surface 36a, and the vertical axis indicates the signal intensity of the light-receiving signal (symbol SG) of the reflected light LA ​​received by the light-receiving surface 36a.

[0099] 16, the light receiving surface 36a of the third embodiment is adjusted in size to include a first light receiving area E1 that receives reflected light LA ​​from the measurement surface Wa within the measurement range WR and a second light receiving area E2 that receives reflected light LA ​​from the measurement surface Wa within the proximity range SR, as in the above embodiments. As a result, a part of the light receiving sensor 36 (light receiving surface 36a) can be allocated as a proximity sensor, as in the above embodiments, and the same effect as in the above embodiments can be obtained.

[0100] Fig. 17 is an explanatory diagram for explaining in detail the second light receiving area E2 described in Fig. 16. As shown in Fig. 17, when the sensitivity [signal strength (voltage value) of the light receiving signal of the reflected light LA)] changes according to the incident position (pixel position on the light receiving surface 36a) of the reflected light LA ​​incident on the light receiving surface 36a, the distance between the sensor head 20 and the measurement surface Wa can be measured according to the magnitude of the sensitivity. In this case, the sensitivity gradually decreases as the incident position of the reflected light LA ​​on the light receiving surface 36a moves away from the center of the pixel position.

[0101] Specifically, when the sensitivity falls below the lower threshold range R1A where the sensitivity can be obtained, the sensitivity becomes zero (including nearly zero) in the non-sensitivity range R2A. Also, when the sensitivity exceeds the upper threshold range R1B where the sensitivity can be obtained, the sensitivity becomes zero in the non-sensitivity range R2B. Here, the lower threshold range R1A and the upper threshold range R1B may not be suitable for distance measurement because of their low sensitivity (poor S / N ratio), and are particularly unsuitable for distance measurement when a lens is selected so that the spot diameter of the measurement light L is small in the first light receiving region E1. For this reason, the lower threshold range R1A and the upper threshold range R1B can also be included in the second light receiving region E2.

[0102] [Fourth embodiment] Next, a surface profile measuring instrument 10 according to a fourth embodiment will be described. In the surface profile measuring instrument 10 according to each of the above embodiments, the approach determination unit 42 performs the approach determination based on whether or not an approach signal is output from the light receiving sensor 36, but in the surface profile measuring instrument 10 according to the fourth embodiment, the approach determination unit 42 performs the approach determination based on the voltage value (signal strength) of the light receiving signal output from the light receiving sensor 36.

[0103] Note that the surface shape measuring machine 10 of the fourth embodiment has basically the same configuration as the surface shape measuring machine 10 of each of the above embodiments, except that it has a function of outputting the voltage value (signal value) of the light reception signal output from the light reception sensor 36 to the approach determination unit 42. Therefore, those that are the same as each of the above embodiments in terms of function or configuration are denoted by the same reference numerals, and their descriptions are omitted.

[0104] FIG. 18 is an explanatory diagram for explaining the approach determination method of the approach determination unit 42 of the fourth embodiment. Here, an example will be described in which the voltage value of the light reception signal output from the light reception sensor 36 increases as the sensor head 20 approaches the measurement surface Wa and the distance between them decreases.

[0105] As shown in FIG. 18, the approach determination unit 42 of the fourth embodiment determines the approach based on whether the voltage value of the light reception signal output from the light reception sensor 36 has reached a predetermined maximum value Vmax (voltage value = Vmax) as shown by reference symbol XVIIIA, or whether the voltage value has reached a predetermined upper limit threshold Th (voltage value = upper limit threshold Th) as shown by reference symbol XVIIIB. In other words, the light reception signal with the maximum value Vmax or the upper limit threshold Th is assigned as the approach signal.

[0106] Note that when the voltage value of the light reception signal output from the light reception sensor 36 decreases as the distance between the sensor head 20 and the measurement surface Wa decreases, the approach determination unit 42 (illustration omitted) determines the approach based on whether the voltage value of the light reception signal output from the light reception sensor 36 has reached a predetermined minimum value or a lower limit threshold. In other words, the light reception signal with the minimum value or the lower limit threshold is assigned as the approach signal.

[0107] [Modification Example] Fig. 19 is an explanatory diagram for explaining a modified example of the surface profile measuring machine 10 of each of the above-mentioned embodiments. In the surface profile measuring machine 10 of each of the above-mentioned embodiments, when the holder 18 is moved downward in the Z direction by the C-axis moving mechanism 16, the sensor head 20 approaches the measurement surface Wa, and conversely, when the holder 18 is moved upward in the Z direction by the C-axis moving mechanism 16, the sensor head 20 moves away from the measurement surface Wa, but the present invention is not limited to this. For example, as shown in Fig. 19, the surface profile measuring machine 10 may be configured such that when the holder 18 is moved downward in the Z direction by the C-axis moving mechanism 16, the sensor head 20 moves away from the measurement surface Wa, and conversely, when the holder 18 is moved upward in the Z direction by the C-axis moving mechanism 16, the sensor head 20 approaches the measurement surface Wa.

[0108] [others] In each of the above embodiments, the light source 30 and the light receiving sensor 36 are provided inside the sensor head 20, but the light source 30 and / or the light receiving sensor 36 may be provided outside the sensor head 20. In this case, a separate optical system is provided to guide the measurement light L from the light source 30 to the sensor head 20, or a separate optical system is provided to guide the reflected light LA ​​incident on the sensor head 20 to the light receiving sensor 36.

[0109] In each of the above embodiments, the C-axis 14, which corresponds to the movement axis of the present invention, is parallel to the Z direction (vertical direction), but it may be parallel to any direction other than the Z direction.

[0110] In each of the above embodiments, the sensor head 20 is moved in the Z direction along the C-axis 14 by the C-axis moving mechanism 16, but instead of moving the sensor head 20, the workpiece W may be moved along the moving axis by various known moving mechanisms.

[0111] In each of the above embodiments, the triangulation method and the color confocal method have been used as examples of methods for measuring the distance from the sensor head 20 to the measurement surface Wa, but the present invention can be applied to various distance measurement methods that can measure distance depending on the incident position of the reflected light LA ​​on the light receiving surface 36a.

[0112] Although the above embodiments have been described taking the surface shape measuring instrument 10 as an example, the present invention is applicable to various shape measuring instruments that perform non-contact measurement of various shapes of the measurement surface Wa. [Explanation of symbols]

[0113] 10... surface shape measuring device, 12... measurement table, 14... C-axis, 16... C-axis movement mechanism, 18... holder, 18a... X-axis movement mechanism, 18b... X-position detection sensor, 20... sensor head, 22... operation unit, 22a... lift lever, 24... monitor, 26... control device, 30... light source, 32... light entrance / exit surface, 32a... light exit window, 32b... light entrance window, 34... lens, 36... light receiving sensor, 36a... light receiving surface, 40... height position adjustment unit, 41... movement amount calculation unit, 42... approach determination unit, 43... adjustment end determination unit , 44...shape measurement control section, 46...distance measurement section, 48...shape calculation section, 100...sensor head, 102...recess, E1...first light receiving area, E2...second light receiving area, H0...reference position, H1...target height position, L...measurement light, LA...reflected light, MR...head position range, R1A...lower threshold range, R1B...upper threshold range, R2A...no sensitivity range, R2B...no sensitivity range, SR...proximity range, Th...upper threshold, Vmax...maximum value, W...workpiece, WR...measurement range, Wa...measurement surface, Δh...movement amount

Claims

1. a sensor head that emits measurement light toward a measurement surface and receives reflected light of the measurement light reflected by the measurement surface; a light receiving sensor having a light receiving surface that receives the reflected light incident on the sensor head, the light receiving sensor changing an incident position of the reflected light on the light receiving surface depending on a distance between the sensor head and the measurement surface; a distance measurement unit that measures the distance based on an incident position of the reflected light with respect to the light receiving surface; a moving mechanism for moving one of the sensor head and the measurement surface toward and away from the other along a predetermined movement axis; Equipped with a measurement range for performing the measurement of the distance in the emission direction of the measurement light is predetermined at a position spaced from the sensor head in the emission direction of the measurement light, When the range between the sensor head and the measurement range is defined as a proximity range, the light receiving surface has a size that can receive the reflected light even when the other is brought close to one side by the moving mechanism to a position where the measurement surface is included in the proximity range.

2. 2. The non-contact shape measuring instrument according to claim 1, wherein the reflected light reflected in a direction different from the incident direction of the measurement light from the measurement surface is incident on the sensor head.

3. 2. The non-contact shape measuring instrument according to claim 1, wherein the measurement light emitted from the sensor head and the reflected light incident on the sensor head are coaxial.

4. a position adjustment unit that drives the moving mechanism to bring the one closer to the other; a movement amount calculation unit that calculates a movement amount of the other object that is required to bring the other object closest to the one object within a range in which the measurement surface is included in the measurement range after the measurement surface reaches the measurement range while the other object is approaching the one object; Equipped with 4. The non-contact shape measuring machine according to claim 1, wherein the position adjustment unit drives the moving mechanism to bring the other one closer to the one by the movement amount after the measurement surface reaches the measurement range while the other one is approaching the one based on a result of receiving the reflected light by the light receiving sensor.

5. 5. The non-contact shape measuring machine according to claim 4, wherein the position adjustment unit stops driving the moving mechanism when the reflected light cannot be received by the light receiving sensor after the measurement surface reaches within the measurement range.

6. a voltage value of a light receiving signal of the reflected light output from the light receiving sensor varies depending on an incident position of the reflected light with respect to the light receiving surface; 4. The non-contact shape measuring machine according to claim 1, further comprising a proximity determination unit that determines whether the other has approached the one to a position where the measurement surface is included within the proximity range based on a voltage value of the light receiving signal output from the light receiving sensor.

7. 4. The non-contact shape measuring instrument according to claim 1, wherein the movement axis is parallel to the vertical direction.

8. 4. A position adjustment method for adjusting the position of the other object along the movement axis in the non-contact shape measuring machine according to claim 1, comprising the steps of: a first approaching step of moving the other one closer to the one by the moving mechanism; a first stopping step of stopping the first approaching step at a position where the measurement surface is included within the measurement range based on a result of reception of the reflected light by the light receiving sensor during execution of the first approaching step; a second approaching step of moving the other object further closer to the one object by the moving mechanism after the first stopping step; a signal output step of outputting a proximity signal indicating the approach of the other object to the one object when the other object approaches the one object to a position where the measurement surface is included in the proximity range based on a result of receiving the reflected light by the light receiving sensor during execution of the second approach step; a separating step of separating the other from the one by the moving mechanism when the signal output step is executed; a second stopping step of stopping the separating step when the measurement surface reaches the measurement range based on a result of receiving the reflected light by the light receiving sensor during the execution of the separating step; The position adjustment method includes the steps of:

9. The position adjustment method according to claim 8 , wherein in the first approaching step, the other of the two is moved at a higher speed than in the second approaching step and the separating step.

Images