Measurement device and laminate molding device

Abstract

To provide a measurement device capable of improving measuring accuracy.SOLUTION: A measurement device comprises a projection part, an imaging part, and an information processing part. A fringe pattern is waveform pattern having down edge or rise edge. The information processing part comprises: a projection control part controlling the projection part so that a phase of the fringe pattern moves; a reflected light quantity change measurement part measuring, on each pixel of an imager, change in reflected light quantity on each point on the surface of a measured object in association with phase change of the fringe pattern; a phase calculation part detecting the down edge or the rise edge from time series of the measured value of reflected light quantity each site on the surface of the measured object, detecting the cycle origin of the fringe pattern, and calculating an initial phase of each pixel on the basis of the detected cycle origin; and a height calculation part calculating a height of each point on the surface of measured object corresponding to each pixel on the basis of the phase of each pixel.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to a measurement apparatus and an additive manufacturing apparatus. [Background technology]

[0002] Three-dimensional additive manufacturing (3DAM) technology is known, which produces three-dimensional objects by irradiating a layer of powder with a beam such as a light beam or an electron beam. This type of manufacturing technology can cause deformation of the object due to the heat of the beam. Furthermore, spatter generated during the manufacturing process can remain, reducing the accuracy of the shape of the object.

[0003] Patent Document 1 discloses an additive manufacturing device that uses a fringe projection method to detect these abnormalities that occur during a manufacturing operation. This additive manufacturing device has a projector that projects a fringe pattern onto a manufactured object. The additive manufacturing device detects irregularities in the manufactured object based on data acquired by capturing an image of the fringe pattern projected onto the manufactured object. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-173103 Summary of the Invention [Problem to be solved by the invention]

[0005] In the fringe projection method, the phase of a fringe pattern (sine wave pattern), whose brightness generally varies sinusoidally, is shifted and projected, and the position (phase) of the observation point on the sine wave pattern is determined by observing the change in the amount of reflected light at the observation point. However, because the period origin of the sine wave pattern is located midway through the change in the amount of reflected light, it is difficult to accurately determine which measurement value corresponds to the measurement value at the period origin. This can result in a decrease in the measurement accuracy of the observation point's phase. In particular, if the number of measurement values ​​sampled is insufficient, the phase error increases, making it difficult to accurately measure the height of each point.

[0006] Although shortening the period of the fringe pattern waveform can improve measurement, it becomes difficult to detect the shift in period if there is a change in height that causes the waveform to shift by more than one period. For this reason, it is desirable to expand the measurement range in the height direction.

[0007] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a measurement device and an additive manufacturing device that can improve measurement performance. [Means for solving the problem]

[0008] In order to solve the above problem, a measurement device according to one aspect of the present disclosure includes a projection unit that projects a fringe pattern onto a surface of an object to be measured, an imaging unit that images the fringe pattern projected onto the surface of the object to be measured, and an information processing unit that processes information of the fringe pattern imaged by the imaging unit and measures the shape of the object to be measured, wherein the fringe pattern is a waveform pattern having a down edge where the amount of reflected light changes from a maximum value to a minimum value or a rising edge where the amount of reflected light changes from a minimum value to a maximum value, the imaging unit has an imager that acquires the amount of reflected light at each point on the surface of the object to be measured, and the information processing unit processes the fringe pattern so that the phase of the fringe pattern moves in a predetermined direction. The apparatus includes a projection control unit that controls the projection unit, a reflected light amount change measurement unit that measures a change in the reflected light amount at each point on the surface of the object to be measured that corresponds to each pixel of the imager due to a phase change of the fringe pattern based on the reflected light amount acquired for one cycle of the waveform pattern by changing the phase of the fringe pattern, a phase calculation unit that detects the down edge or the rising edge from a time series of measured values ​​of the reflected light amount at each pixel to detect a periodic origin of the fringe pattern and measures an initial phase of each pixel based on the detected periodic origin, and a height calculation unit that measures the height from the measurement reference plane of each point on the surface of the object to be measured that corresponds to each pixel based on the phase of each pixel.

[0009] An additive manufacturing apparatus according to one aspect of the present disclosure includes the above-described measuring device, a stage having a manufacturing surface on which an object is additively manufactured, a powder supply unit that supplies powder onto the manufacturing surface, and a head that irradiates a beam onto the powder on the manufacturing surface to sinter it. [Effects of the Invention]

[0010] According to the measuring device and additive manufacturing device of the present disclosure, it is possible to improve measurement performance. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a configuration diagram of an additive manufacturing apparatus according to a first embodiment of the present disclosure. [Figure 2]FIG. 2 is a functional block diagram of a forming control unit according to the first embodiment of the present disclosure. [Figure 3] FIG. 2 is a configuration diagram of a projection unit according to the first embodiment of the present disclosure. [Figure 4] FIG. 2 is a schematic diagram of a fringe pattern according to the first embodiment of the present disclosure. [Figure 5] FIG. 2 is a schematic diagram of a fringe pattern according to the first embodiment of the present disclosure. [Figure 6] FIG. 2 is a configuration diagram of an imaging unit according to the first embodiment of the present disclosure. [Figure 7] FIG. 2 is a schematic diagram illustrating a measurement method according to the first embodiment of the present disclosure. [Figure 8] FIG. 2 is a functional block diagram of an information processing unit according to the first embodiment of the present disclosure. [Figure 9] 1 is a flowchart showing a procedure for additive manufacturing according to a first embodiment of the present disclosure. [Figure 10] 3 is a flowchart showing the procedure of a measurement method according to the first embodiment of the present disclosure. [Figure 11] 5 is a flowchart showing a procedure for measuring the height of an object to be measured according to the first embodiment of the present disclosure. [Figure 12] FIG. 4 is a diagram showing a change in the amount of reflected light at each measurement point due to a phase shift of a fringe pattern according to the first embodiment of the present disclosure. [Figure 13] FIG. 4 is a diagram showing a change in the amount of reflected light at one measurement point according to the first embodiment of the present disclosure. [Figure 14] FIG. 10 is a schematic diagram of a fringe pattern according to a second embodiment of the present disclosure. [Figure 15] FIG. 10 is a diagram showing a change in the amount of reflected light at one measurement point according to the second embodiment of the present disclosure. [Figure 16] FIG. 10 is a configuration diagram of an additive manufacturing apparatus according to a third embodiment of the present disclosure. [Figure 17] 11A and 11B are diagrams illustrating an example of a change in the amount of reflected light and a pulse signal at one measurement point according to a third embodiment of the present disclosure. [Figure 18] FIG. 11 is a diagram showing an example of a change in the amount of reflected light after correction at one measurement point according to the third embodiment of the present disclosure. [Figure 19] FIG. 10 is a schematic diagram of a fringe pattern according to a fourth embodiment of the present disclosure. [Figure 20] FIG. 10 is a schematic diagram of a fringe pattern according to a fifth embodiment of the present disclosure. [Figure 21] FIG. 13 is a schematic diagram of a fringe pattern according to a sixth embodiment of the present disclosure. [Figure 22] FIG. 1 is a hardware configuration diagram according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0012] (First embodiment) Hereinafter, a layered manufacturing apparatus 1 according to a first embodiment of the present disclosure will be described with reference to FIGS. In the following, one horizontal direction is referred to as the X direction, and the horizontal direction perpendicular to the X direction is referred to as the Y direction. The vertical direction is referred to as the Z direction. The Z direction is perpendicular to the X and Y directions.

[0013] (Additive manufacturing equipment) 1 forms an object 2 by additive manufacturing (AM) technology. The additive manufacturing apparatus 1 includes a chamber 3, a cylinder 4, a stage 5, a powder supply unit 6, a coater 7, a head 8, a modeling control unit 20, and a measuring device 9.

[0014] (Chamber) The chamber 3 has a housing 3a, a beam window 3b, a projection window 3c, and an imaging window 3d. The housing 3a accommodates therein a cylinder 4, a stage 5, a powder supply unit 6, and a coater . The beam window 3b is provided in the center of the top of the housing 3a. The projection window 3c and the imaging window 3d are provided on the upper part of the housing 3a. In Fig. 1, the projection window 3c and the imaging window 3d are shown as being horizontally opposed to each other with the beam window 3b in between, but this is not limiting. The positional relationship between the beam window 3b, the projection window 3c, and the imaging window 3d may be changed as desired.

[0015] (cylinder) The cylinder 4 is formed in a cylindrical shape that extends in the vertical direction. A stage 5 is housed inside the cylinder 4.

[0016] (stage) The stage 5 is formed in the shape of a flat plate extending horizontally. The stage 5 has a modeling surface 5a on its upper surface. The modeling surface 5a extends horizontally. The object 2 is layer-by-layer manufactured on the modeling surface 5a. The stage 5 is provided so as to be movable in the vertical direction along the cylinder 4. In other words, the height of the modeling surface 5a can be changed.

[0017] (Powder supply section) The powder supply unit 6 supplies powder 6a onto the modeling surface 5a.

[0018] (Coater) The coater 7 moves horizontally to flatten the powder 6a supplied onto the building surface 5a, thereby forming a powder bed 6b on the building surface 5a.

[0019] (head) The head 8 is located outside the chamber 3. The head 8 is located directly above the center of the build surface 5a, with the beam window 3b in between. The head 8 irradiates a beam 8a, such as a light beam or an electron beam, onto the powder bed 6b on the build surface 5a. This beam 8a passes through the beam window 3b and is irradiated onto the powder bed 6b. The powder bed 6b irradiated with the beam 8a is sintered. As a result, the object 2 is built on the build surface 5a.

[0020] (Modeling Control Unit) As shown in FIG. 2, the modeling control unit 20 has the functions of a stage control unit 21, a powder supply control unit 22, a coater control unit 23, and a head control unit 24. The stage control unit 21 controls the stage 5 and sets the height of the modeling surface 5a. The powder supply control unit 22 controls the powder supply unit 6 to cause the powder supply unit 6 to supply powder 6a onto the modeling surface 5a. The coater control unit 23 controls the coater 7 to level the powder 6a on the modeling surface 5a and form a powder bed 6b. The head control unit 24 controls the head 8 to irradiate the beam 8a onto the powder bed 6b on the modeling surface 5a.

[0021] (Measuring equipment) The measuring device 9 is a device that measures the surface shapes of the object 2 and the powder bed 6b by a fringe projection method. Hereinafter, the object to be measured by the measuring device 9 will be referred to as a measurement target 11. The measurement target 11 is, for example, the object 2 or the powder bed 6b. The measurement device 9 includes a projection unit 30, an imaging unit 40, and an information processing unit 50.

[0022] (projection section) The projection unit 30 is disposed outside the chamber 3. The projection unit 30 is disposed above the printing surface 5a across a projection window 3c. The projection unit 30 is also disposed at an angle with respect to the printing surface 5a, at a position offset from directly above the printing surface 5a so as not to interfere with the head 8. The projection unit 30 projects a fringe pattern 36 (see FIG. 4) onto an area including the surface of the object 11 to be measured.

[0023] As shown in FIG. 3, the projection unit 30 includes a light source 32, a mask 33, an actuator , and a projection lens .

[0024] (light source) The light source 32 irradiates radial light toward the measurement object 11. Here, a straight line connecting the center of the light source 32 and the center of a projection lens 35 (described later) is the optical axis O1 of the light source 32. This optical axis O1 passes through the center 10a of the printing surface 5a.

[0025] (mask) The mask 33 is disposed on the optical axis O1 of the light source 32, between the light source 32 and the printing surface 5a. The mask 33 is formed by drawing a plurality of striped patterns 33b on a transparent substrate 33a made of a light-transmitting material, such as glass. The striped patterns 33b extend in a first direction (e.g., the X direction in FIG. 4). The plurality of striped patterns 33b are periodically arranged along a second direction (e.g., the Y direction in FIG. 4). As shown in FIG. 4, a striped fringe pattern 36 is generated when light emitted from the light source 32 passes through the mask 33. As shown in FIG. 5, the mask 33 has a continuous arrangement of striped patterns 33b whose transmittance gradually increases from a minimum value Min to a maximum value Max along the second direction. The maximum and minimum values ​​Min of the transmittance may be set arbitrarily. Therefore, the fringe pattern 36 of this embodiment is a so-called sawtooth wave pattern in which the amount of reflected light increases linearly from a minimum value Min to a maximum value Max during one cycle (2π), and has a down edge that falls back to the minimum value Min at the cycle origin of the next cycle. Note that in other embodiments, the transmittance of each stripe pattern 33b may gradually decrease from the maximum value Max to the minimum value Min. In this case, the fringe pattern 36 is a sawtooth wave pattern (so-called inverse sawtooth wave pattern) in which the amount of reflected light decreases linearly from a maximum value Max to a minimum value Min during one cycle (2π), and has a rising edge that rises back to the maximum value Max at the cycle origin of the next cycle.

[0026] (actuator) The actuator 34 moves the mask 33 in a second direction (the Y direction in FIG. 4), which is the arrangement direction of the striped pattern 33b. The projection unit 30 changes the phase of the fringe pattern 36 by moving the mask 33 using the actuator 34.

[0027] (projection lens) The projection lens 35 is disposed on the optical axis O1 of the light source 32, between the mask 33 and the modeling surface 5a.

[0028] (Mask and projection lens arrangement) The mask 33 is tilted with respect to the optical axis O1 of the light source 32. That is, the mask 33 is disposed so as to intersect with a plane perpendicular to the optical axis O1 of the light source 32. In this embodiment, the mask 33 and the projection lens 35 are disposed parallel to the printing surface 5a so as to form a shift lens optical system.

[0029] The projection unit 30 may be a projector that projects the fringe pattern 36. In this case, the projection unit 30 moves the fringe pattern 36 and changes the phase, for example, by sequentially switching and projecting a plurality of projection pattern images in which the phase of the above-described fringe pattern 36 is changed.

[0030] (imaging unit) The imaging unit 40 is located outside the chamber 3. The imaging unit 40 is located above the printing surface 5a, with the imaging window 3d in between. To prevent the imaging unit 40 from interfering with the head 8, the projection unit 30 is located offset from directly above the printing surface 5a and tilted relative to the printing surface 5a. While FIG. 1 illustrates an example configuration in which the imaging unit 40 is located horizontally opposite the projection unit 30, with the head 8 in between, this configuration is not limiting. The positional relationship between the head 8, the projection unit 30, and the imaging unit 40 may be changed according to the positional relationship between the beam window 3b, the projection window 3c, and the imaging window 3d. The imaging unit 40 captures the fringe pattern 36 projected onto the surface of the measurement object 11 through the imaging window 3d. In this embodiment, the imaging unit 40 continuously captures the fringe pattern 36 while the mask 33 is moving. When the projection unit 30 is a projector, the imaging unit 40 continuously captures images of the fringe pattern 36 projected by the projection unit 30. As shown in FIG. 6, the imaging unit 40 includes a camera 41 and a light receiving lens 42.

[0031] (camera) The camera 41 has an imager 44 .

[0032] (Imager) The imager 44 acquires the amount of reflected light at each point on the surface of the object 11 onto which the fringe pattern 36 is projected. As shown in Fig. 7, the imager 44 has a plurality of pixels 45. Each of the plurality of pixels 45 acquires the amount of reflected light at one point on the surface of the object 11.

[0033] (receiving lens) The light receiving lens 42 is disposed on an optical axis O2 connecting the center 44b of the imager 44 and the center of the modeling surface 5a, between the imager 44 and the modeling surface 5a.

[0034] (Imager and receiving lens arrangement) In this embodiment, the imager 44 and the light receiving lens 42 are arranged parallel to the modeling surface 5a so as to form a shift lens optical system.

[0035] (Information Processing Department) The information processing unit 50 processes information on the fringe pattern 36 captured by the imaging unit 40, and calculates the shape of the measurement object 11. As shown in Fig. 8, the information processing unit 50 has the functions of a projection control unit 51, an imaging control unit 52, a memory unit 53, a reflected light amount change measurement unit 54, a phase calculation unit 55, a height calculation unit 56, and a surface shape calculation unit 57.

[0036] (Projection control unit) The projection control unit 51 controls the projection unit 30 to project a fringe pattern 36 onto the surface of the object to be measured 11. Furthermore, the projection control unit 51 moves the mask 33 using the actuator 34 to change the phase of the fringe pattern 36. If the projection unit 30 is a projector, the projection control unit 51 changes the phase of the fringe pattern 36 by switching the projection pattern image and causing the projection unit 30 to project it.

[0037] (imaging control unit) The imaging control unit 52 controls the imaging unit 40 to cause the imaging unit 40 to capture an image of the fringe pattern 36 projected onto the surface of the object 11 to be measured.

[0038] (Storage part) The memory unit 53 stores information such as the image of the fringe pattern 36 captured by the imaging unit 40, the phase of the fringe pattern 36 at each pixel 45 of the imager 44 acquired by the phase calculation unit 55 described later, and the height of the surface of the object to be measured 11 acquired by the height calculation unit 56 described later.

[0039] (Reflected light amount change measurement unit) The reflected light amount change measuring unit 54 measures the change in the reflected light amount at each point on the surface of the measured object 11 corresponding to each pixel 45 of the imager 44 due to the phase change of the fringe pattern 36, based on the reflected light amount obtained multiple times at each pixel 45 of the imager 44 by changing the phase of the fringe pattern 36.

[0040] (Phase calculation section) The phase calculation unit 55 calculates the initial phase of the fringe pattern 36 in each pixel 45 of the imager 44 based on the change in the amount of reflected light measured by the reflected light amount change measurement unit 54 .

[0041] (Height calculation part) The height calculation unit 56 calculates the height of each point on the surface of the object to be measured 11 corresponding to each pixel 45, based on the change in the amount of reflected light measured at each pixel 45. In this embodiment, the height calculation unit 56 performs further arithmetic processing based on the initial phase calculated by the phase calculation unit 55 based on the change in the amount of reflected light, and calculates the height of each point on the surface of the object to be measured 11 corresponding to each pixel 45.

[0042] (Surface shape calculation section) The surface shape calculation unit 57 aggregates the heights of each point on the surface of the measurement object 11 to calculate the surface shape of the model 2. For example, the surface shape calculation unit 57 specifies the surface shape of the measurement object 11 by plotting each point on the surface of the measurement object 11 in a virtual space. The surface shape of the measurement object 11 here means the uneven shape of the surface of the measurement object 11 expressed by the height from the modeling surface 5a.

[0043] (Additive manufacturing procedure) The procedure for additive manufacturing will be described below with reference to the flowchart in FIG. First, the stage control unit 21 moves the stage 5 in the -Z direction (step S11). This adjusts the build surface 5a to an appropriate height. After step S11, the powder supply control unit 22 controls the powder supply unit 6 to supply powder 6a to the build surface 5a (step S12). After step S12, the coater control unit 23 controls the coater 7 to level the powder 6a on the build surface 5a and form a powder bed 6b (step S13). After step S13, the head control unit 24 controls the head 8 to irradiate the powder bed 6b on the build surface 5a with a beam 8a (step S14). This sinters the powder bed 6b, forming a sintered layer. By repeating steps S11 to S14, multiple sintered layers are stacked on the build surface 5a in the Z direction. In this way, the object 2 is layer-by-layer manufactured on the build surface 5a.

[0044] (Measurement method procedure) 10, a procedure for measuring the shape of the object 11 (e.g., the object 2 or the powder bed 6b) using the measuring device 9 will be described below. In this embodiment, the measuring device 9 calculates the shape of the object 11 using a phase shift method. First, the measurement device 9 calculates the height of each point on the object to be measured 11 corresponding to each pixel 45 of the imager 44 (step S21). Hereinafter, the procedure of step S21 will be described in detail with reference to the flowchart of FIG.

[0045] As shown in Figure 7, the procedure of step S21 will be described using an example in which the height of measurement point P1 on the surface of the object to be measured 11 corresponding to one pixel 45a of the imager 44 is calculated. Figure 7 illustrates the camera base point PA that constitutes the imaging unit 40, and the projection base point PB of the fringe pattern 36 projected by the projection unit 30. The line connecting the camera base point PA and the projection base point PB is defined as base line L1. The line passing through the camera base point PA and pixel 45a is defined as camera line of sight line L2. Measurement point P1 corresponding to pixel 45a is on this camera line of sight line L2.

[0046] First, the projection control unit 51 causes the projection unit 30 to project the fringe pattern 36 onto the surface of the object to be measured 11 (step S31). Here, an example will be described in which the fringe pattern 36 is a sawtooth wave pattern that repeats a cycle in which the amount of reflected light increases linearly according to the phase.

[0047] Thereafter, the imaging control unit 52 causes the imaging unit 40 to capture an image of the fringe pattern 36 projected onto the surface of the object 11 (step S32). In step S32, the amount of reflected light at the measurement point P1 corresponding to the pixel 45a is acquired in the pixel 45a. In step S32, the projection control unit 51 drives the actuator 34 to move the mask 33 by at least one period of the fringe pattern 36. This changes the phase of the fringe pattern 36, and the amount of reflected light at the measurement point P1 changes in accordance with the phase change of the fringe pattern 36. At this time, the imaging unit 40 continuously captures images of the fringe pattern 36 while the mask 33 is moving. Note that if the projection unit 30 is a projector, the projection control unit 51 outputs a control signal to the projection unit 30 at predetermined time intervals to project the next projection pattern image, and the imaging control unit 52 repeatedly controls the imaging unit 40 to continuously capture the fringe pattern 36. This allows the amount of reflected light at the pixel 45a at each time to be acquired. The amount of light reflected by the pixel 45a is acquired n times. The measured values ​​of the amount of light reflected by the pixel 45a are stored in the storage unit 53.

[0048] After step S32, the reflected light amount change measuring unit 54 measures the measured values ​​I1 to I2 acquired by the pixel 45a. n 12 shows an example in which the fringe pattern 36 is projected while shifting the phase at each coordinate in the Y direction on the surface of the object 11 to be measured. Measurement values ​​I1 to I8 in FIG. 12 exemplify some of the measurement values ​​of the amount of reflected light measured at each time in the pixel 45a. As shown in FIG. 13, the reflected light amount change measuring unit 54 displays a plurality of measurement values ​​I1 to I8 of the amount of reflected light of the pixel 45a at each time on a graph with the horizontal axis representing time and the vertical axis representing the amount of reflected light. n Plot the

[0049] In this embodiment, since the fringe pattern 36 is a sawtooth wave pattern, as in the example of FIG. 13, the measured value of the reflected light amount increases gradually within one period, but the measured value of the reflected light amount at the end of one period and the first measured value of the next period is the maximum reflected light amount I H Minimum reflected light intensity I L Therefore, the maximum reflected light intensity I H Minimum reflected light intensity I L By detecting the measurement value that has changed, it becomes easy to accurately detect the period origin of the fringe pattern 36. In the example of Fig. 13, the measurement value I8 is the period origin.

[0050] Furthermore, when the projection unit 30 is configured to move the mask 33, the movement speed of the mask 33 may change according to an acceleration / deceleration pattern (a pattern consisting of three sections: an acceleration section, a constant speed section, and a deceleration section) known as trapezoidal drive. In this case, the movement speed of the mask 33 is not constant between the acceleration section and the deceleration section, and the phase shift amount of the fringe pattern 36 is not constant. As a result, the measurement values ​​measured in these acceleration and deceleration sections change nonlinearly. Therefore, in this embodiment, the reflected light amount change measurement unit 54 corrects the measurement values ​​that are presumed to be affected by changes in the movement speed. For example, the reflected light amount change measurement unit 54 preliminarily determines the change in the reflected light amount of the fringe pattern 36 when the actuator 34 moves at a constant speed, and sets an ideal straight line LN of the change in reflected light amount from the slope of the calculated line. Alternatively, in order to suppress the effects of acceleration and deceleration accompanying the trapezoidal drive of the actuator 34, the reflected light amount change measurement unit 54 may exclude data from a certain period after the start of measurement and a certain period before the end of measurement from the time series data of the reflected light amount, and set the approximated straight line LN using the least squares method from the time series data in the middle of the measurement period. Note that since the approximated straight line may not be obtained correctly before or after the period origin, if the period origin is near the center of the measurement period, the approximated straight line LN is obtained from the time series data before or after the period origin, whichever has the larger number of data. The reflected light amount change measurement unit 54 corrects the measurement values ​​so that they fit the set straight line LN. In the example of FIG. 13, there is a deviation in the time axis direction in the acceleration / deceleration section and deceleration section of the actuator 34 compared to the constant velocity section. Therefore, the measurement values ​​I1 to I3, I, which are deviated in the time axis direction from the straight line LN, are used. n-2 ~I nis corrected in the time axis direction to fit the straight line LN. In this way, the reflected light intensity change measurement unit 54 can correct the measurement values ​​so that the influence of changes in moving speed is suppressed based on the sawtooth wave pattern characteristic that the measurement values ​​change linearly in each period. In conventional techniques using a sinusoidal fringe pattern 36, if the phase shift amount is not constant, the accuracy of the sinusoidal curve derived from each measurement value decreases. Correction to fit the measurement values ​​to the sinusoidal curve requires complex arithmetic processing. In contrast, in this embodiment, a time series of measurement values ​​in which the influence of changes in moving speed is suppressed can be obtained by the simple correction process of fitting the measurement values ​​to the straight line LN as described above. Furthermore, if the projection unit 30 is a projector, the timing from when a control signal is input from the projection control unit 51 to when the fringe pattern 36 is actually projected may vary due to arithmetic processing or the like of the projector. In this case, the time series of measurement values ​​also changes nonlinearly. Therefore, even when the projection unit 30 is a projector, the effect of variations in the projection timing of the projector can be suppressed by performing correction processing using the ideal straight line LN similarly obtained in advance.

[0051] After step S33, the phase calculation unit 55 calculates the initial phase φ of the pixel 45a based on the change in the amount of reflected light of the pixel 45a (step S34). For example, the phase calculation unit 55 calculates the initial phase φ of the pixel 45a based on the change in the amount of reflected light of the pixel 45a when the amount of reflected light reaches the maximum amount of reflected light I H Minimum reflected light intensity I L The down edge where the signal changes to a signal with a period origin is detected, and this is detected as the measurement value of the period origin. Since the sawtooth wave pattern shows a simple increase (or a simple decrease) in the amount of reflected light, the phase calculation unit 55 can calculate the initial phase φ of the pixel 45a from the waveform amplitude and the initially acquired measurement value I1 of the amount of reflected light.

[0052] After step S34, the height calculation unit 56 calculates the height of the measurement point P1 corresponding to the pixel 45a based on the initial phase φ of the pixel 45a (step S35). In step S35, the height calculation unit 56 calculates the azimuth angle θB from the projection base point PB to the measurement point P1 corresponding to the pixel 45a (the angle θB between the baseline L1 and the straight line connecting the projection base point PB and the measurement point P1). Since the positional relationship between the projection center of the projection lens 35 and the mask 33 is determined, the azimuth angle θn (n = 1, 2, 3, ..., N) of the period origin of each of the N sawtooth wave patterns of the mask 33 can be determined in advance. As shown in FIG. 13, the azimuth angle θB of the measurement point P1 corresponding to the pixel 45a can be calculated from the azimuth angle θn of the period origin of the sawtooth wave pattern and the initial phase φ of the pixel 45a by θB = θn + φ. The height calculation unit 56 performs calculations using the principles of triangulation based on the coordinates (XA, YA, ZA) of the camera base point PA and the coordinates (XB, YB, ZB) of the projection base point PB in the world coordinate system, the angle θA of the measurement point P1 as seen from the camera base point PA (the angle θA between the line connecting the camera base point PA and pixel 45a and the baseline L1), and the angle θB of the measurement point P1 as seen from the projection base point PB calculated based on the initial phase φ, to determine the coordinates (X1, Y1, Z1) of the measurement point P1 corresponding to pixel 45a. The coordinates of the camera base point PA and the projection base point PB are calibrated (defined) in advance using a point on the printing surface 5a as the origin of the world coordinate system. By using a point on the printing surface 5a as the origin, the height of the measurement point P1 from the printing surface 5a can be directly determined as the Z coordinate value (Z1) of the measurement point P1. Through the above procedure, calculation of the height of the measurement point P1 of the object to be measured 11 corresponding to one pixel 45a is completed.

[0053] The above-described procedure of steps S31 to S35 is performed for each pixel 45 of the imager 44. As a result, the height of each point on the surface of the object to be measured 11 corresponding to each pixel 45 is calculated. The height of each point on the surface of the object to be measured 11 corresponding to each pixel 45 is stored in the storage unit 53. With the above procedure, the calculation of the height at each point on the surface of the object to be measured 11 corresponding to each pixel 45 is completed (step S21).

[0054] After step S21, the surface shape calculation unit 57 aggregates the heights of each point on the surface of the object to be measured 11 corresponding to each pixel 45 calculated in step S21, and calculates the surface shape of the object to be measured 11 (step S22). For example, the surface shape calculation unit 57 specifies the surface shape of the object to be measured 11 by plotting each point on the surface of the object to be measured 11 in a virtual space. Through the above procedure, calculation of the shape of the object to be measured 11 is completed.

[0055] (Action and effect) The measuring device 9 and the layered manufacturing device 1 of this embodiment provide the following advantageous effects. In this embodiment, the measurement device includes a projection unit 30, an imaging unit 40, and an information processing unit 50. The projection unit 30 projects a fringe pattern 36 onto the surface of the measurement object 11. The imaging unit 40 captures an image of the fringe pattern 36 projected onto the surface of the measurement object 11. The information processing unit 50 processes information about the fringe pattern 36 captured by the imaging unit 40 and measures the shape of the measurement object 11. The fringe pattern 36 is a waveform pattern having a down edge where the amount of reflected light changes from a maximum value to a minimum value or a rising edge where the amount of reflected light changes from a minimum value to a maximum value. The imaging unit 40 has an imager 44 that acquires the amount of reflected light at each point on the surface of the measurement object 11 onto which the fringe pattern 36 is projected. The information processing unit 50 has a projection control unit 51, a reflected light amount change measurement unit 54, a phase calculation unit 55, and a height calculation unit 56. The projection control unit 51 controls the projection unit 30 so that the phase of the fringe pattern 36 moves in a predetermined direction (the Y direction in FIG. 4 ). The reflected light amount change measurement unit 54 measures the change in the reflected light amount at each point on the surface of the object 11 corresponding to each pixel 45 of the imager 44 due to the phase change of the fringe pattern 36, based on the reflected light amount acquired for one cycle of the waveform pattern by changing the phase of the fringe pattern 36. The phase calculation unit 55 detects a down edge or a rising edge from the time series of measured values ​​of the reflected light amount at each pixel 45 to detect the period origin of the fringe pattern 36, and calculates the initial phase φ of each pixel 45 based on the period origin. The height calculation unit 56 calculates the height of each point on the surface of the object 11 corresponding to each pixel 45 based on the initial phase φ of each pixel 45.

[0056] For example, when a sinusoidal wave pattern is used as a fringe pattern as in the past, the period origin of the sinusoidal wave pattern is located midway through the change in the amount of reflected light, making it difficult to accurately determine which measurement value corresponds to the period origin. This can reduce the accuracy of calculating the phase of the sinusoidal wave pattern obtained from the measurement values ​​of each pixel. In particular, when the number of sampled measurement values ​​is small, phase errors increase, making it difficult to accurately calculate the height of each point on the surface of the object 11 corresponding to each pixel. In contrast, the measurement device 9 according to the present embodiment, with its configuration described above, detects a down edge or a rising edge where the amount of reflected light changes sharply, and uses this as a reference to accurately detect the period origin of the waveform contained in the fringe pattern 36. By accurately detecting the period origin, the measurement device 9 can accurately calculate the initial phase φ of each pixel 45, thereby improving the accuracy of calculating the height of the measurement point corresponding to each pixel 45.

[0057] The projection unit 30 may also have a configuration including a light source 32 that irradiates light toward the object 11, a mask 33 that transmits the light irradiated from the light source 32 and generates a fringe pattern 36, and an actuator 34 that moves the mask 33. In this case, the projection control unit 51 of the information processing unit 50 controls the actuator 34 so that the mask 33 moves in a second direction (the Y direction in FIG. 4).

[0058] In this manner, the measurement device 9 can change the phase of the fringe pattern 36 simply by moving the mask 33. This reduces the time required to change the phase of the fringe pattern 36. This increases the number of times the amount of reflected light is measured at each point on the surface of the object 11 per unit time. Furthermore, since the time required to change the phase of the fringe pattern 36 is shorter than when switching projected pattern images using a projector, the time required to measure the shape of the object 11 is reduced. Furthermore, in this embodiment, the projection unit 30 can change the phase of the fringe pattern 36 with a simple configuration including the light source 32, the mask 33, and the actuator 34, which allows the projection unit 30 to be made smaller.

[0059] The projection unit 30 may be a projector. In this case, the projection control unit 51 of the information processing unit 50 outputs a control signal to the projection unit 30 so as to project a projection pattern image in which the phase of the fringe pattern 36 is shifted in a predetermined direction (the Y direction in FIG. 4) at predetermined time intervals.

[0060] In this way, for example, the above-mentioned measuring device 9 can be configured by simply updating the software of a measuring device having an existing projector, such as by adding a projection pattern image of the fringe pattern 36 and each functional unit of the information processing unit 50. This makes it possible to reduce the manufacturing costs and introduction costs of the measuring device 9.

[0061] The fringe pattern 36 is a sawtooth wave pattern. The phase calculation unit 55 of the information processing unit 50 detects the down edge or the rising edge as the period origin of the sawtooth wave pattern, and calculates the initial phase φ of each pixel 45 from the position of the period origin in the time series of measurement values.

[0062] As mentioned above, the sawtooth wave pattern has a maximum reflected light intensity I at the origin of the period. H Minimum reflected light intensity I L to, or minimum reflected light amount I L Maximum reflected light intensity I HThe sawtooth wave pattern has such characteristics that the measurement device 9 can easily detect the period origin accurately based on the abrupt change in the amount of reflected light. By accurately detecting the period origin, the initial phase φ of each pixel 45 can be calculated more accurately. Furthermore, with a sawtooth wave pattern, the change in transmittance of the mask 33 can be simplified more than with a sine wave pattern, making it possible to manufacture the mask 33 easily and accurately.

[0063] In addition, the reflected light amount change measurement unit 54 of the information processing unit 50 corrects measurement values ​​that deviate from a line LN, which is an ideal line of the reflected light amount change obtained in advance or an approximate line obtained from a time series of measurement values, by moving them onto the line LN.

[0064] In this way, the measurement device 9 can correct any variations in the measured values ​​that occur due to variations in the phase shift amount of the fringe pattern 36 caused by changes in the moving speed of the actuator 34 or variations in the timing of switching the projection pattern image of the projector. By using the time series of the corrected measured values ​​in this way, the measurement device 9 can easily calculate the initial phase φ accurately.

[0065] (Second embodiment) Next, a second embodiment will be described with reference to Figures 14 and 15. Components common to the above-described embodiment will be given the same reference numerals and detailed description will be omitted.

[0066] (fringe pattern) Taking the mask 33 as an example, as shown in FIG. 14, the mask 33 is formed by alternating stripe patterns 33b with a maximum transmittance (Max) and stripe patterns 33b with a minimum transmittance (Min). The substrate 33a may be exposed without the stripe patterns 33b with a maximum transmittance (Max). That is, the fringe pattern 36 according to this embodiment is a rectangular wave pattern in which one cycle (2π) is made up of a section C1 with a maximum reflected light amount (Max) and a section C2 with a minimum reflected light amount (Min). While FIG. 14 shows an example in which the ratio of the section C1, where the maximum reflected light amount (Max) continues, to the section C2, where the minimum reflected light amount (Min) continues, is the same (both are 1 / 2 cycle), this is not limiting. The ratios of the sections C1 and C2 to one cycle may be different, and may be set arbitrarily. The ratios of the sections C1 and C2 to one cycle are pre-recorded by the information processing unit 50. In the example of FIG. 14, the rising edge at which the amount of reflected light rises to the maximum value Max is set as the cycle origin, but the falling edge at which the amount of reflected light falls to the minimum value Min may also be set as the cycle origin.

[0067] If the measurement time for one cycle can be made sufficiently long, the mask 33 may be moved by the actuator 34 to project the fringe pattern 36. However, if the measurement time for one cycle is short (i.e., if high-speed measurement is required), changes in the movement speed due to the trapezoidal drive of the actuator 34 described above will distort the square wave pattern obtained from the time series of measurement values ​​in a portion of the interval after the mask 33 starts to move and before it stops moving. Therefore, if it is necessary to shorten the measurement time, it is desirable to use a projector as the projection unit 30 and have the projection pattern image switched and projected by the projection unit 30 at predetermined intervals.

[0068] (Measurement method procedure) The procedure of the measurement method in this embodiment is the same as that in the first embodiment (FIG. 10). However, part of the processing in the procedure of step S21 (FIG. 11) for measuring the height of each point on the surface of the measurement object 11 differs from that in the first embodiment. Here, the details of step S21 (steps S31 to S35) will be described.

[0069] First, the projection control unit 51 causes the projection unit 30 to project the fringe pattern 36 onto the surface of the object to be measured 11 (step S31). Thereafter, the imaging control unit 52 causes the imaging unit 40 to capture an image of the fringe pattern 36 projected onto the surface of the object to be measured 11 (step S32). These processes are the same as those in the first embodiment.

[0070] After step S32, the reflected light amount change measuring unit 54 measures the measured values ​​I1 to I2 acquired by the pixel 45a. n 15, the reflected light amount change measuring unit 54 plots the measured values ​​I1 to I2 of the pixel 45a at each time on a graph with the horizontal axis representing time and the vertical axis representing the amount of reflected light. n In this embodiment, since the fringe pattern 36 is a rectangular wave pattern, the maximum reflected light amount I H and minimum reflected light amount I L A waveform pattern consisting of the following can be obtained.

[0071] After step S33, the phase calculation unit 55 calculates the initial phase φ of the pixel 45a based on the change in the amount of reflected light of the pixel 45a (step S34). The phase calculation unit 55 measures the elapsed time until the first rising edge or down edge (first edge) and the elapsed time until the next down edge or rising edge (second edge), with the imaging start time set as time 0. The phase calculation unit 55 also calculates the elapsed time until the first edge, the elapsed time until the second edge, and the maximum amount of reflected light I for one period of the square wave pattern. H The section where the minimum reflected light intensity I L The initial phase φ of the pixel 45a is calculated based on the ratio of the duration of the period.

[0072] In the example of FIG. 15, a rectangular wave pattern is projected and captured at each time from the first imaging time t0 to the last imaging time tn, and the first down edge (measured value I t1 ) is detected, and at time t2, the next rising edge (measured value I t2The phase calculation unit 55 calculates the time dt1 that has elapsed since the first imaging time t0 until the time t1 at which the first down edge is detected, and the time dt2 that has elapsed since the time t1 until the time t2 at which the next rising edge is detected (i.e., the minimum reflected light amount I L The maximum reflected light intensity I H Section C1 and minimum reflected light amount I L The proportion of the section C2 in the period is known in advance. Therefore, the phase calculation unit 55 calculates the time corresponding to one period of the square wave pattern from the elapsed time dt2 from when the first edge is detected until the next edge is detected and the proportion of the section C1 or the section C2 in one period. For example, the minimum reflected light amount I L If the section C2 in which the period continues is 1 / 2 period, one period 2π of the square wave pattern corresponds to the duration dt2×2 on the time axis. Therefore, the period origin of this square wave pattern on the time axis is the time measured by dt2×2 before the time t2. The phase calculation unit 55 calculates the period origin on the time axis (i.e., the maximum reflected light amount I H the starting point of the reflection) and the maximum reflected light intensity I H The phase calculation unit 55 calculates the shift amount dt3 of the square wave pattern on the time axis from the duration dt1 of the square wave pattern. Furthermore, since it is known that one period 2π of the square wave pattern corresponds to time dt2×2 on the time axis, it can calculate the initial phase φ of the pixel 45a from the shift amount dt3.

[0073] After step S34, the height calculation unit 56 calculates the height of the measurement point P1 corresponding to the pixel 45a based on the initial phase φ of the pixel 45a (step S35). This process is the same as in the first embodiment. The above procedure completes the calculation of the height of the measurement point P1 on the object 11 corresponding to one pixel 45a. Similar processing is performed for the other pixels 45 on the imager 44.

[0074] (Action and effect) The measuring device 9 and the layered manufacturing device 1 of this embodiment provide the following advantageous effects. In this embodiment, the fringe pattern 36 is a square wave pattern. The phase calculation unit 55 of the information processing unit 50 calculates the initial phase φ of each pixel 45 based on the elapsed time from the first edge, which is a down edge or a rising edge that is first detected in the time series of measurement values, to the second edge, which is a rising edge or a down edge that is next detected, and the proportion of the section in one cycle of the square wave pattern where the amount of reflected light is maximum or minimum.

[0075] Changes in the environment during measurement, such as temperature, can cause fluctuations in the amount of reflected light. This can lead to measurement errors in the amount of reflected light, reducing the accuracy of phase calculations. On the other hand, time is not affected by the environment, unlike the amount of reflected light, and its resolution can be easily increased. Therefore, the measurement device 9 according to this embodiment uses a binary square wave pattern for the fringe pattern 36 and calculates the initial phase φ using the elapsed time to the first edge and the elapsed time from the first edge to the second edge, thereby suppressing the effects of measurement errors in the amount of reflected light and enabling highly accurate calculation of the initial phase φ. Furthermore, a square wave pattern can simplify the transmittance change of the mask 33 compared to a sine wave pattern or a sawtooth wave pattern, making it possible to manufacture the mask 33 more easily and accurately.

[0076] (Third embodiment) Next, a third embodiment will be described with reference to Figures 16 to 18. Components common to the above-described embodiments will be given the same reference numerals and detailed description will be omitted.

[0077] (projection section) As shown in FIG. 16, the projection unit 30 according to this embodiment further includes a signal output unit 37.

[0078] (Signal output section) The signal output section 37 outputs a pulse signal in accordance with the phase shift of the fringe pattern 36 .

[0079] When the projection unit 30 is configured to move the mask 33 , the signal output unit 37 is a linear encoder attached to the actuator 34 or a rotary encoder attached to the drive motor of the actuator 34 .

[0080] When the projection unit 30 is a projector, it is a signal generator that outputs a pulse signal at the timing when the projector completes switching of the projection pattern image.

[0081] (Information Processing Department) Furthermore, in the information processing unit 50 according to this embodiment, the functions of the imaging control unit 52 and the reflected light amount change measuring unit 54 are different from those in the second embodiment.

[0082] (imaging control unit) When the imaging control unit 52 detects from the pulse signal that the phase of the fringe pattern 36 has shifted by a predetermined amount, it controls the imaging unit 40 to image the fringe pattern 36 .

[0083] (Reflected light amount change measurement unit) As described above, when the projection unit 30 is configured to move the mask 33, any change in the movement speed due to trapezoidal drive of the actuator 34 will distort the square wave pattern obtained from the time series of measurement values. Furthermore, even when the projection unit 30 is a projector, as described above, there is a possibility that the projection timing of the fringe pattern 36 will vary, and in this case too, the square wave pattern obtained from the time series of measurement values ​​will be distorted. Therefore, the reflected light amount change measurement unit 54 according to this embodiment corrects the time axis of the graph on which the time series of measurement values ​​is plotted based on the pulse signal.

[0084] (Measurement method procedure) The procedure of the measurement method in this embodiment is the same as that in the second embodiment. However, a part of the process in step S21 (FIG. 11) for calculating the height of each point on the surface of the object to be measured 11 differs from that in the second embodiment. Here, the details of step S21 (steps S31 to S35) will be described.

[0085] First, the projection control unit 51 causes the projection unit 30 to project the fringe pattern 36 onto the surface of the object to be measured 11 (step S31).

[0086] Thereafter, the imaging control unit 52 causes the imaging unit 40 to capture an image of the fringe pattern 36 projected onto the surface of the object to be measured 11 (step S32).

[0087] If the projection unit 30 is configured to move the mask 33, in step S32, the projection control unit 51 drives the actuator 34 to move the mask 33. This changes the phase of the fringe pattern 36, and the amount of reflected light at the measurement point P1 corresponding to the pixel 45a changes in accordance with the phase change of the fringe pattern 36. At this time, the signal output unit 37 of the projection unit 30 outputs a control signal to the imaging unit 40 to capture the fringe pattern 36 each time it receives a pulse signal. Note that the imaging control unit 52 may calculate the amount of movement of the mask 33 from the pulse signal and output a control signal to the imaging unit 40 each time the mask 33 moves a predetermined amount. Also, if the projection unit 30 is a projector, in step S32, the projection control unit 51 controls the projection unit 30 to project the next projection pattern image each time one image capture is completed. When the imaging control unit 52 receives a pulse signal indicating the completion of the projection pattern image switching, it outputs a control signal to the imaging unit 40 to capture the fringe pattern 36. The imaging unit 40 receives this control signal and captures an image of the fringe pattern 36 .

[0088] After step S32, the reflected light amount change measuring unit 54 measures the measured values ​​I1 to I2 acquired by the pixel 45a. n Based on this, the change in the amount of reflected light is measured (step S33).

[0089] FIG. 17 shows, as an example, pulse signals outputted every time the mask 33 moves, and the measured values ​​I1 to I2 of the amount of reflected light measured by the pixel 45a in response to the pulse signals. nAs shown in (b) of FIG. 17, the output interval of the pulse signal is constant in the constant velocity section of the actuator 34, but in the acceleration section and deceleration section, the output interval of the pulse signal is longer than in the constant velocity section. Therefore, as shown in (a) of FIG. 17, the measured values ​​I1 to I n If the measured time is plotted on a graph, a square wave pattern identical to the fringe pattern 36 will not be obtained. This will result in errors when calculating the time corresponding to one cycle (2π) from the elapsed time dt2, as in the second embodiment ( FIG. 15 ), or when calculating the shift amount dt3 of the square wave pattern from the elapsed time dt1. For this reason, in this embodiment, the reflected light amount change measurement unit 54 corrects the square wave pattern based on the pulse signals acquired from the signal output unit 37. For example, the reflected light amount change measurement unit 54 calculates the amount of movement of the mask 33 (the amount of movement of the phase of the fringe pattern 36) from the number of acquired pulse signals and plots the result on a graph whose horizontal axis represents the amount of movement instead of the time axis. FIG. 18 shows an example in which each measurement value is plotted on a graph whose horizontal axis represents the amount of movement. In this way, the reflected light amount change measurement unit 54 can accurately measure the fringe pattern 36 projected at the measurement point P1 without being affected by changes in the moving speed of the mask 33 or variations in the timing of switching the projected pattern image of the projector. 17 and 18 show an example in which the fringe pattern 36 is a square wave, but the present invention is not limited to this. The fringe pattern 36 may also be a sine wave pattern or a sawtooth wave pattern.

[0090] After step S33, the phase calculation unit 55 calculates the initial phase φ of pixel 45a based on the change in the amount of reflected light from pixel 45a (step S34). In FIG. 18, dp1 is the movement amount of the mask 33 from the first imaging time t0 to the time t1 when the first down edge is detected, dp2 is the movement amount of the mask 33 from the time t1 when the first edge is detected to the time t2 when the next edge is detected, and dp3 is the amount of deviation from the period origin. The phase calculation unit 55 replaces time with the movement amount and calculates the initial phase φ in the same way as in the second embodiment (FIG. 15). Furthermore, after step S34, the height calculation unit 56 calculates the height of measurement point P1 corresponding to pixel 45a based on the initial phase φ of pixel 45a (step S35). The processes of steps S34 to S35 are the same as those in the second embodiment. The above procedure completes the measurement of the height of the measurement point P1 on the object 11 corresponding to one pixel 45a. Similar processing is performed for the other pixels 45 of the imager 44.

[0091] (Action and effect) The measuring device 9 and the layered manufacturing device 1 of this embodiment provide the following advantageous effects. In this embodiment, projection unit 30 further includes signal output unit 37 that outputs a pulse signal in response to a shift in the phase of fringe pattern 36. Information processing unit 50 further includes an imaging control unit 52 that, when it detects from the pulse signal that the phase of fringe pattern 36 has shifted a predetermined amount, controls imaging unit 40 to capture an image of fringe pattern 36. Reflected light amount change measurement unit 54 of information processing unit 50 corrects a waveform obtained by plotting a time series of measurement values ​​so that it becomes a waveform corresponding to the amount of phase shift of fringe pattern 36 based on the pulse signal.

[0092] In this way, the measuring device 9 can accurately measure the change in the amount of reflected light at each pixel 45 that accompanies a change in the phase of the fringe pattern 36 without being affected by variations in the trapezoidal drive of the actuator 34 or the timing of switching the projector's projection pattern image. This improves the accuracy of calculating the initial phase φ of each pixel 45 and the height of each point on the object to be measured 11 corresponding to each pixel 45.

[0093] (Fourth embodiment) Next, a fourth embodiment will be described with reference to Fig. 19. Components common to the above-described embodiments are given the same reference numerals, and detailed description thereof will be omitted.

[0094] (fringe pattern) As shown in FIG. 19, the fringe pattern 36 of this embodiment is formed by combining a first waveform W1, whose cycle spans the entire area of ​​the fringe pattern 36 in a predetermined direction, with a second waveform W2, whose cycle is shorter than that of the first waveform W1. Taking the mask 33 as an example, the first waveform W1 varies the transmittance of a predetermined wavelength in a sinusoidal manner over one cycle along the second direction (Y direction) of the mask 33. The second waveform W2 varies the transmittance of a wavelength different from that of the first waveform W1 in a sawtooth manner along the second direction (Y direction) of the mask 33. The second waveform W2 is formed by repeating a sawtooth wave for multiple cycles (F1 to Fn). For example, the light source 32 is a white light source including at least three wavelengths (RGB), and the first waveform W1 varies the amount of reflected light of one of the RGB wavelengths (e.g., red), and the second waveform W2 varies the amount of reflected light of a wavelength different from the first wavelength (e.g., green). The camera 41 is a three-chip color camera.

[0095] (Measurement method procedure) The procedure of the measurement method in this embodiment is the same as that in the first embodiment (FIG. 10). However, part of the processing in the procedure of step S21 (FIG. 11) for measuring the height of each point on the surface of the measurement object 11 differs from that in the first embodiment. Here, the details of step S21 (steps S31 to S35) will be described.

[0096] First, the projection control unit 51 causes the projection unit 30 to project the fringe pattern 36 onto the surface of the object to be measured 11 (step S31). Thereafter, the imaging control unit 52 causes the imaging unit 40 to capture the fringe pattern 36 projected onto the surface of the object to be measured 11 (step S32). In this embodiment, the first waveform W1 is obtained by changing the amount of reflected red light, and the second waveform W2 is obtained by changing the amount of reflected green light. The imaging unit 40 outputs to the information processing unit 50 an R image obtained by capturing only the red wavelength as an image of the first waveform W1, and a G image obtained by capturing only the green wavelength as an image of the second waveform W2.

[0097] After step S32, the reflected light amount change measuring unit 54 measures the change in the reflected light amount for each wavelength at the measurement point P1 corresponding to pixel 45a based on the image of the first waveform W1 (R image) and the image of the second waveform W2 (G image) captured by the imaging unit 40 (step S33).

[0098] After step S33, the phase calculation unit 55 calculates the initial phase φ of the pixel 45a based on the change in the amount of reflected light for each wavelength of the pixel 45a (step S34). First, the phase calculation unit 55 calculates the initial phase φ1 of the sine wave of the pixel 45a from the change in the amount of reflected light of the first waveform W1 (sine wave pattern) in the R image. This calculation method may use conventional technology. For example, the initial phase φ1 of the first waveform W1 (sine wave) can be calculated based on the change in the amount of reflected light between the R image capturing the initially projected fringe pattern 36 and the R image captured after the fringe pattern 36 is moved by one period of the second waveform W2. The phase calculation unit 55 also calculates the initial phase φ2 of the second waveform W2 (sawtooth wave) of the pixel 45a based on the change in the amount of reflected light in multiple G images. The calculation method for the initial phase φ2 of the sawtooth wave pattern is the same as in the first embodiment. Furthermore, the phase calculation unit 55 determines which cycle of the second waveform W2 (sawtooth wave) the waveform in which the initial phase φ2 was detected belongs to, based on the initial phase φ1 of the first waveform W1 (sine wave). For example, the phase calculation unit 55 references a table that associates the phase of the first waveform W1 with the number of cycles of the second waveform W2, and determines which cycle of the second waveform W2 the waveform in which the initial phase φ2 was detected belongs to.

[0099] After step S34, the height calculation unit 56 calculates the height of the measurement point P1 corresponding to the pixel 45a based on the period and initial phase φ2 of the second waveform at the pixel 45a (step S35). Using a waveform with a shorter period improves measurement accuracy in the height direction. However, if the period is shortened, a height error equivalent to one period occurs at measurement point P1 corresponding to pixel 45a if the projected waveform shifts by more than one period (2π). However, in this embodiment, the period of the initial phase φ2 of the second waveform W2 of pixel 45a can be determined based on the initial phase φ1 of the first waveform W1 of pixel 45a. As described in the first embodiment, the second waveform W2 (sawtooth wave pattern) with a short period requires a pattern shift of one period to calculate the initial phase φ2 of pixel 45a. On the other hand, by using a sinusoidal wave pattern for the first waveform W1 with a long period, the initial phase φ1 of the first waveform W1 can be calculated by simply shifting the pattern slightly (by one period of the short-period second waveform W2). This allows the measurement range in the height direction to be expanded compared to the first embodiment, while maintaining the same movement amount of actuator 34 as in the first embodiment. The purpose of combining the long-period first waveform W1 is to expand the measurement range in the height direction using the short-period second waveform W2. Therefore, the accuracy of the initial phase φ1 of the first waveform W1 only needs to be high enough to detect one period of the second waveform W2. For example, if there are 20 periods of the second waveform W2 across the entire fringe pattern 36, the phase of the first waveform W1 needs to be calculated with an accuracy of approximately 360° / 20 = ±6.5°. By combining the first waveform W1 and the second waveform W2 in this way, height can be calculated accurately even in areas where there is a height change that shifts by one period of the short-period second waveform W2.

[0100] The above procedure completes the calculation of the height of the measurement point P1 on the object 11 corresponding to one pixel 45a. Similar processing is performed for the other pixels 45 on the imager 44.

[0101] (Action and effect) The measuring device 9 and the layered manufacturing device 1 of this embodiment provide the following advantageous effects. In this embodiment, the fringe pattern 36 is a waveform pattern obtained by combining a first waveform W1, in which the amount of reflected light of a first wavelength varies over one period across the entire area of ​​the fringe pattern 36 in a predetermined direction (the Y direction in FIG. 19 ), and a second waveform W2, in which the amount of reflected light of a second wavelength different from the first wavelength varies over a shorter period than that of the first waveform W1. The reflected light amount change measurement unit 54 measures changes in the amount of reflected light of each of the first waveform W1 and the second waveform W2 at each point on the surface of the object 11 corresponding to each pixel 45 of the imager 44, resulting from changes in the phase of the fringe pattern 36, based on the amount of reflected light acquired multiple times by changing the phase of the fringe pattern 36. The phase calculation unit 55 calculates the initial phases φ1 and φ2 of the first waveform W1 and the second waveform W2 at each pixel 45 from the time series of measured values ​​of the amount of reflected light of each of the first waveform W1 and the second waveform W2 at each pixel 45. The height calculation unit 56 calculates the height of each point on the surface of the object to be measured 11 corresponding to each pixel 45 based on the initial phases φ1, φ2 of the first waveform W1 and the second waveform W2 of each pixel 45.

[0102] By doing this, the measurement device 9 can determine, from the first waveform W1, the position (phase) of each point on the object to be measured 11 corresponding to each pixel 45 within the entire fringe pattern 36. Therefore, even if there is a height change that exceeds one period of the second waveform W2, the height can be calculated with high accuracy. In other words, the measurement range in the height direction can be expanded. This allows the period of the second waveform W2 to be shorter than before, thereby improving the measurement accuracy of each measurement point. Furthermore, since two different waveform patterns can be projected simultaneously, the time required to capture and measure each waveform pattern can be reduced.

[0103] Furthermore, the phase calculation unit 55 determines the period of the second waveform W2 over the entire area of ​​the fringe pattern 36 from the initial phase φ1 of the first waveform W1. The height calculation unit 56 calculates the height of each point on the surface of the object to be measured 11 corresponding to each pixel 45, based on the period and initial phase φ2 of the second waveform W2.

[0104] By identifying the period of the second waveform W2 at which the waveform at which the initial phase φ2 of each pixel 45 is detected corresponds, the measurement device 9 can measure, for example, an object to be measured 11 having a height change that causes the second waveform W2 to shift by one or more periods. This makes it possible to shorten the period of the second waveform W2 compared to conventional methods and improve the measurement accuracy at each measurement point.

[0105] (Fifth embodiment) Next, a fifth embodiment will be described with reference to Fig. 20. The fifth embodiment is obtained by changing the fringe pattern of the fourth embodiment. Components common to the fourth embodiment are given the same reference numerals and detailed description thereof will be omitted.

[0106] (fringe pattern) As shown in FIG. 20 , in the fringe pattern 36 according to this embodiment, the first waveform W1 is composed of an ascending pattern W1a, in which the amount of reflected light gradually increases, and a descending pattern W1b, in which the amount of reflected light gradually decreases, along a predetermined direction (Y direction) of the fringe pattern 36. The ascending pattern W1a and the descending pattern W1b each vary the amount of reflected light at different wavelengths. In this embodiment, the ascending pattern W1a of the first waveform W1 varies the amount of reflected light of red among RGB, the descending pattern W1b of the first waveform W1 varies the amount of reflected light of blue, and the second waveform W2 varies the amount of reflected light of green. Therefore, the image capturing unit 40 outputs to the information processing unit 50 an R image capturing only the red wavelength as the image of the ascending pattern W1a, a B image capturing only the blue wavelength as the image of the descending pattern W1b, and a G image capturing only the green wavelength as the image of the second waveform W2.

[0107] (Measurement method procedure) The procedure of the measurement method in this embodiment is the same as that in the fourth embodiment. However, among the processing steps of step S21 (FIG. 11) for measuring the height of each point on the surface of the measurement object 11, a part of the processing steps S33 to S34 differs from that in the fourth embodiment. The differences from the fourth embodiment will be described below.

[0108] In step S33, the reflected light amount change measuring unit 54 measures the change in the reflected light amount for each wavelength at the measurement point P1 corresponding to pixel 45a based on the image (R image) of the rising pattern W1a of the first waveform W1, the image (B image) of the falling pattern W1b, and the image of the second wavelength (G image) captured by the imaging unit 40 (step S33).

[0109] After step S33, the phase calculation unit 55 calculates the initial phase φ of the pixel 45a based on the change in the amount of reflected light for each wavelength of the pixel 45a (step S34). First, the phase calculation unit 55 calculates the position (initial phase φ1) of the pixel 45a in the entire fringe pattern 36 from (Dr-Db) / (Dr+Db), where Dr is the amount of reflected light obtained from the rising pattern W1a (R image) of the first waveform W1 and Db is the amount of reflected light obtained from the falling pattern W1b (B image). The phase calculation unit 55 also calculates the initial phase φ2 of the pixel 45a on the second waveform W2 (sawtooth wave) based on the change in the amount of reflected light in the multiple G images. The phase calculation unit 55 also determines, from the initial phase φ1 of the first waveform W1, which cycle of the multiple second waveforms W2 (sawtooth waves) the waveform at which the initial phase φ2 was detected belongs. For example, as in the fourth embodiment, the phase calculation unit 55 refers to a table that associates the initial phase φ1 of the first waveform W1 with the number of periods of the second waveform W2, and determines which period of the second waveform W2 the waveform in which the initial phase φ2 is detected is.

[0110] For a sine wave pattern, the maximum reflected light intensity I H and minimum reflected light amount I L (i.e., near phases of 90° and 270°), the difference in the amount of reflected light due to changes in phase is small, which may make it difficult to accurately calculate the phase. On the other hand, in this embodiment, by using a combination of two waveforms, an ascending pattern W1a and a descending pattern W1b, as the first waveform W1, it is possible to accurately calculate the phase regardless of the position (phase) of the first waveform W1 projected onto the measurement point P1 corresponding to pixel 45a.

[0111] After step S34, the height calculation unit 56 calculates the height of the measurement point P1 corresponding to the pixel 45a based on the period and initial phase φ2 of the second waveform W2 at the pixel 45a (step S35). The above procedure completes the measurement of the height of the measurement point P1 on the object 11 corresponding to one pixel 45a. Similar processing is performed for the other pixels 45 of the imager 44.

[0112] (Action and effect) The measuring device 9 and the layered manufacturing device 1 of this embodiment provide the following advantageous effects. In this embodiment, the first waveform W1 of the fringe pattern 36 consists of an ascending pattern W1a in which the amount of reflected light of one wavelength gradually increases along a predetermined direction of the fringe pattern 36, and a descending pattern W1b in which the amount of reflected light of another wavelength gradually decreases along the predetermined direction of the fringe pattern 36.

[0113] As mentioned above, in the sine wave pattern, the maximum reflected light intensity I H and minimum reflected light amount I LAround this point (i.e., around phases of 90° and 270°), the difference in the amount of reflected light due to phase changes is small, making it difficult to accurately measure the phase. On the other hand, in this embodiment, by using a combination of two waveforms, an ascending pattern W1a and a descending pattern W1b, as the first waveform W1, it is possible to accurately measure the phase regardless of the position (phase) of the first waveform W1 projected at the measurement point P1 corresponding to pixel 45a. Furthermore, in the case of a sinusoidal pattern, unless the amount of reflected light at the maximum value (phase 90°) or the minimum value (phase 270°) is known, the accurate phase cannot be determined solely from the amount of reflected light at other phases. Therefore, even if the intensity of the light source is constant, the sinusoidal pattern cannot accurately detect the phase when the reflectance of the object to be measured changes. Furthermore, because the emission intensity of many light sources changes depending on the ambient temperature, the sinusoidal pattern cannot accurately detect the phase even when the intensity of the light source changes. On the other hand, in this embodiment, the total amount of reflected light of the ascending pattern W1a and the descending pattern W1b (Dr+Db) is a constant value, so by normalizing with this value, the phase can be accurately detected regardless of changes in the reflectance of the object 11 or the ambient temperature.

[0114] (Sixth embodiment) Next, a sixth embodiment will be described with reference to Fig. 21. The sixth embodiment is obtained by changing the fringe pattern of the fourth and fifth embodiments. Components common to the fourth and fifth embodiments are given the same reference numerals, and detailed description thereof will be omitted.

[0115] (fringe pattern) As shown in FIG. 21 , the fringe pattern 36 according to this embodiment is obtained by superimposing a signal representing the period on a portion of the waveform of each period. The fringe pattern 36 according to this embodiment does not include multiple types of waveforms combined together, as in the fourth and fifth embodiments, but includes only one type of waveform. While FIG. 21 shows an example in which the fringe pattern 36 is a sawtooth wave pattern, other waveforms (sine wave, square wave, etc.) may also be used. The signal superimposed on the waveform of each period includes, for example, a start bit (1 bit), data bits (several bits), and a parity bit (1 bit), such as an asynchronous signal. The data bits include a period number. The signal superimposed on the waveform of each period has a transmittance (amount of reflected light) that is increased by a certain percentage from the original waveform. While FIG. 21 shows an example in which only one superimposed signal is included in one waveform period, this is not limiting. In other embodiments, two of the same superimposed signals may be included in one waveform period.

[0116] (Measurement method procedure) The procedure of the measurement method in this embodiment is the same as that in the fourth embodiment. However, among the processing steps of step S21 (FIG. 11) for calculating the height of each point on the surface of the object to be measured 11 corresponding to each pixel 45 of the imager 44, a part of the processing steps S33 to S34 differs from that in the fourth embodiment. The differences from the fourth embodiment will be described below.

[0117] In step S33, the reflected light amount change measuring unit 54 measures the change in the reflected light amount at the measurement point P1 corresponding to the pixel 45a based on the fringe pattern 36 captured by the imaging unit 40 (step S33).

[0118] After step S33, the phase calculation unit 55 calculates the initial phase φ of the pixel 45a based on the change in the amount of reflected light of the pixel 45a (step S34). First, the phase calculation unit 55 obtains the initial phase φ of the fringe pattern at the pixel 45a from the time series of the measured values ​​of the amount of reflected light, as in the first embodiment. That is, the down edge (or the rising edge) indicating the period origin is detected from the graph on which the time series of the measured values ​​is plotted. The maximum reflected light amount I before and after this period origin is calculated. Hand minimum reflected light intensity I L The waveform amplitude of the sawtooth wave pattern can be determined from

[0000] . Because the sawtooth wave pattern exhibits a simple increase (or decrease) in the amount of reflected light, the phase calculation unit 55 can calculate the initial phase φ of pixel 45a from the waveform amplitude and the first measurement value I1 of the amount of reflected light. The phase calculation unit 55 also analyzes the signal included in the time series of measurement values ​​to determine which period of the waveform measured by pixel 45a belongs to. Specifically, the phase calculation unit 55 obtains the period number included in the signal by detecting and decoding a signal whose reflected light amount is greater than a certain percentage from the straight line LN (FIG. 13) of the sawtooth wave pattern. Note that the measurement value of this signal portion can be corrected to reduce the amount of reflected light by a certain percentage, thereby restoring the original waveform without the signal superimposition. For example, when a sine wave pattern is used, the initial phase φ can be calculated more accurately by removing the change in the amount of reflected light due to the signal superimposition and restoring the original sine wave pattern. In other words, the fringe pattern 36 of this embodiment is also characterized in that the amount of reflected light (transmittance) of the signal portion is increased at a constant rate from the original waveform, which makes it easier to restore the original waveform pattern and has the effect of enabling the initial phase φ to be determined with high accuracy.

[0119] Also, for example, suppose that at the start of imaging, a waveform is observed in pixel 45a from the middle of the superimposed signal. In this case, if only one superimposed signal is included in one cycle, moving one cycle and collecting one cycle of images will result in a difference in the period number of the superimposed signal included in the image immediately after imaging begins and the period number of the superimposed signal included in the image immediately before imaging ends, making it impossible to obtain the correct period number. To address this situation, as described above, two of the same superimposed signals may be included in one cycle. If the superimposed signal begins immediately after imaging begins, that is, if the superimposed signal cannot be obtained continuously from the beginning (start bit), the phase calculation unit 55 discards this superimposed signal. Furthermore, the phase calculation unit 55 sets the period number included in the superimposed signal that can be read continuously and completely from the beginning to the end of the next image captured as positive. This allows the phase calculation unit 55 to obtain the correct period number regardless of the waveform position at the start of imaging.

[0120] After step S34, the height calculation unit 56 calculates the height of measurement point P1 corresponding to pixel 45a based on the period and phase φ of the waveform at measurement point P1 (step S35). Because the initial phase φ should appear before the period origin, the period number in which the initial phase φ exists is the previous period number. As described above, the azimuth angle θn of the period origin of each period is known. Therefore, the azimuth angle θB of measurement point P1 corresponding to pixel 45a can be calculated from the azimuth angle θn of the period origin of the period number read from the signal and the initial phase φ of pixel 45a by θB = θn + φ. The method of calculating the height of measurement point P1 corresponding to pixel 45a using the azimuth angle θB is the same as in the first embodiment. The above procedure completes the calculation of the height of the measurement point P1 on the object 11 corresponding to one pixel 45a. Similar processing is performed for the other pixels 45 on the imager 44.

[0121] (Action and effect) The measuring device 9 and the layered manufacturing device 1 of this embodiment provide the following advantageous effects. In this embodiment, the fringe pattern 36 is a waveform pattern in which the amount of reflected light changes periodically in a predetermined direction, and is a waveform pattern in which a signal indicating the number of periods is superimposed for each period. The phase calculation unit 55 measures the initial phase φ and period of each pixel 45 from the time series of measured values ​​of the amount of reflected light at each pixel 45. The height calculation unit 56 measures the height of each point on the surface of the object to be measured 11 corresponding to each pixel 45, based on the initial phase φ and period of each pixel 45.

[0122] In this way, the measurement device 9 can easily and accurately identify the waveform cycle of the fringe pattern 36 measured at each pixel 45. This makes it possible to measure even an object 11 whose height changes by more than one waveform cycle, for example.

[0123] Furthermore, in the fringe pattern 36, the amount of reflected light of the signal is greater by a certain percentage than in the waveform pattern.

[0124] In this way, the measuring device 9 can easily remove the signal and restore the original waveform pattern, and can accurately determine the initial phase φ.

[0125] (Hardware configuration) The forming control unit 20 and the information processing unit 50 in the above-described embodiments and modifications are implemented in a computer 1100 shown in Fig. 22. Fig. 22 is a schematic block diagram showing the configuration of a computer according to each embodiment. The computer 1100 includes a processor 1110, a main memory 1120, a storage 1130, and an interface 1140.

[0126] The operations of the above-mentioned functional units of the forming control unit 20 and the information processing unit 50 are stored in the form of a program in the storage 1130. The processor 1110 reads the program from the storage 1130, loads it into the main memory 1120, and executes the above-mentioned processing in accordance with the program. The processor 1110 also allocates a storage area in the main memory 1120 in accordance with the program.

[0127] The program may be for realizing some of the functions to be performed by the computer 1100. For example, the program may be combined with other programs already stored in the storage 1130 or other programs implemented in other devices to perform the functions. Furthermore, the computer 1100 may include a custom LSI (Large Scale Integrated Circuit) such as a PLD (Programmable Logic Device) in addition to or instead of the above configuration. Examples of PLDs include PAL (Programmable Array Logic), GAL (Generic Array Logic), CPLD (Complex Programmable Logic Device), and FPGA (Field Programmable Gate Array). In this case, some or all of the functions to be performed by the processor 1110 may be realized by the integrated circuit.

[0128] Examples of storage 1130 include a magnetic disk, a magneto-optical disk, and a semiconductor memory. Storage 1130 may be an internal medium directly connected to the bus of computer 1100, or an external medium connected to computer 1100 via interface 1140 or a communication line. Furthermore, when this program is distributed to computer 1100 via a communication line, computer 1100 that receives the program may load the program into main memory 1120 and execute the above-mentioned processing. Storage 1130 may also be a non-transitory tangible storage medium.

[0129] The program may also be a program for realizing part of the above-described functions. Furthermore, the program may be a so-called differential file (differential program) that realizes the above-described functions in combination with another program already stored in storage 1130.

[0130] (Other embodiments) The above describes in detail the embodiments of the present disclosure with reference to the drawings, but the specific configuration is not limited to this embodiment, and design changes and the like are also included within the scope that does not deviate from the gist of the present disclosure.

[0131] In the above embodiment, the measuring device 9 measures the shapes of the object 2 and the powder bed 6b manufactured by the additive manufacturing apparatus 1, but this is not limiting. For example, the measuring device 9 may be used to measure the shape of an object manufactured by an external device.

[0132] In the above embodiment, the case where the projection unit 30 and the image capture unit 40 are provided outside the chamber 3 has been described, but this is not limiting. The projection unit 30 and the image capture unit 40 may also be provided inside the chamber 3.

[0133] In the above embodiment, the case where one projection lens 35 is provided in the projection unit 30 has been described, but the present invention is not limited to this. A plurality of projection lenses 35 may be provided in the projection unit 30.

[0134] In the above embodiment, the case where one light receiving lens 42 is provided in the imaging section 40 has been described, but this is not limitative. The imaging section 40 may be provided with a plurality of light receiving lenses 42.

[0135] <Additional Notes> The measuring device and the additive manufacturing device described in each embodiment can be understood, for example, as follows.

[0136] (1) A measurement device 9 according to a first aspect includes a projection unit 30 that projects a fringe pattern 36 onto the surface of an object to be measured 11, an imaging unit 40 that images the fringe pattern 36 projected onto the surface of the object to be measured 11, and an information processing unit 50 that processes information on the fringe pattern 36 imaged by the imaging unit 40 and measures the shape of the object to be measured 11, the fringe pattern 36 being a waveform pattern having a down edge where the amount of reflected light changes from a maximum value to a minimum value or a rising edge where the amount of reflected light changes from a minimum value to a maximum value, the imaging unit 40 having an imager 44 that acquires the amount of reflected light at each point on the surface of the object to be measured 11, and the information processing unit 50 processes the information on the fringe pattern 36 so that the phase of the fringe pattern 36 moves in a predetermined direction. a reflected light amount change measurement unit 54 that measures the change in the amount of reflected light at each point on the surface of the object to be measured 11 corresponding to each pixel 45 due to the phase change of the fringe pattern 36, based on the amount of reflected light acquired multiple times at each pixel 45 of the imager 44 while changing the phase of the fringe pattern 36; a phase calculation unit 55 that detects a down edge or a rising edge from the time series of measured values ​​of the amount of reflected light at each pixel 45 to detect the periodic origin of the fringe pattern 36 and calculates an initial phase φ of each pixel 45 based on the periodic origin; and a height calculation unit 56 that calculates the height of each point on the surface of the object to be measured 11 corresponding to each pixel 45, based on the initial phase φ of each pixel 45.

[0137] According to this aspect, it becomes easy to accurately detect the period origin of the waveform included in the fringe pattern 36, using the detected down edge or rising edge as a reference. By accurately detecting the period origin, the initial phase φ of each pixel 45 can be measured with high precision, and therefore the measurement precision of the height of each point on the surface of the object to be measured 11 corresponding to each pixel 45 can also be improved.

[0138] (2) The measuring device 9 according to the second aspect is the measuring device 9 of (1), in which the projection unit 30 has a light source 32 that irradiates light toward the object to be measured 11, a mask 33 that transmits the light irradiated from the light source 32 and generates a fringe pattern 36, and an actuator 34 that moves the mask 33, and the projection control unit 51 controls the actuator 34 so that the mask 33 moves in a predetermined direction.

[0139] According to this aspect, the phase of the fringe pattern 36 can be changed simply by moving the mask 33. This reduces the time required to change the phase of the fringe pattern 36. This increases the number of times the amount of reflected light is measured at each point on the surface of the object 11 per unit time. Furthermore, since the time required to change the phase of the fringe pattern 36 is shorter than when switching images using a projector, the time required to measure the shape of the object 11 is reduced. Furthermore, the projection unit 30 can change the phase of the fringe pattern 36 with a simple configuration consisting of the light source 32, the mask 33, and the actuator 34, which allows the projection unit 30 to be made smaller.

[0140] (3) The measuring device 9 according to the third aspect is the measuring device 9 of (1), in which the projection unit 30 is a projector, and the projection control unit 51 outputs a control signal to the projection unit 30 so as to project a projection pattern image in which the phase of the fringe pattern 36 is shifted in a predetermined direction at predetermined time intervals.

[0141] According to this aspect, the above-described measuring device 9 can be configured by simply updating the software of, for example, a measuring device having an existing projector, by adding a projection pattern image of the fringe pattern 36 and each functional unit of the information processing unit 50. This allows the manufacturing cost and introduction cost of the measuring device 9 to be reduced.

[0142] (4) The measuring device 9 according to the fourth aspect is any one of the measuring devices 9 of (1) to (3), in which the fringe pattern 36 is a sawtooth wave pattern, and the phase calculation unit 55 detects the down edge or the rising edge as the period origin of the sawtooth wave pattern, and measures the initial phase φ of each pixel 45 from the position of the period origin in the time series of measurement values.

[0143] According to this embodiment, it is easy to accurately detect the period origin based on the steep change in the amount of reflected light of the sawtooth wave. Accurate detection of the period origin allows for more accurate measurement of the initial phase φ of each pixel 45. Furthermore, with a sawtooth wave pattern, the change in transmittance of the mask 33 can be simplified compared to a sine wave pattern, making it possible to easily and accurately manufacture the mask 33.

[0144] (5) The measuring device 9 according to the fifth aspect is the measuring device 9 of (4), in which the reflected light amount change measuring unit 54 corrects the measured values ​​that deviate from the straight line LN, which is an ideal straight line of the reflected light amount change that has been determined in advance or an approximate straight line determined from the time series of the measured values, by moving them onto the straight line LN.

[0145] According to this embodiment, when the phase shift amount of the fringe pattern 36 is not constant due to changes in the moving speed of the actuator 34 or variations in the timing of switching images by the projector, causing variations in the measured values, this can be corrected. By using the time series of the corrected measured values ​​in this way, the measuring device 9 can easily calculate the initial phase φ accurately.

[0146] (6) The measuring device 9 according to the sixth aspect is any one of the measuring devices 9 of (1) to (3), in which the fringe pattern 36 is a rectangular wave pattern consisting of a section C1 in which the amount of reflected light is at its maximum and a section C2 in which the amount of reflected light is at its minimum, and the phase calculation unit 55 calculates the initial phase φ of each pixel 45 based on the elapsed time from the first edge, which is the down edge or rising edge that is first detected in the time series of measurement values, to the second edge, which is the rising edge or down edge that is next detected, and the proportion of the section C1 in which the amount of reflected light is at its maximum or the proportion of the section C2 in which the amount of reflected light is at its minimum in one cycle of the rectangular wave pattern.

[0147] According to this embodiment, by making the fringe pattern 36 a binary rectangular wave pattern and measuring the initial phase φ using the elapsed time to the first edge and the elapsed time from the first edge to the second edge, it is possible to suppress the influence of measurement errors in the amount of reflected light and calculate the initial phase φ with high accuracy. Furthermore, with a rectangular wave pattern, the change in transmittance of the mask 33 can be simplified more than with a sine wave pattern or a sawtooth wave pattern, making it possible to manufacture the mask 33 more easily and accurately.

[0148] (7) A measuring device 9 according to a seventh aspect is any one of the measuring devices 9 of (1) to (6), wherein the projection unit 30 further has a signal output unit 37 that outputs a pulse signal in accordance with the phase shift of the fringe pattern 36, the information processing unit 50 further has an imaging control unit 52 that controls the imaging unit 40 to image the fringe pattern when it detects from the pulse signal that the phase of the fringe pattern 36 has shifted a predetermined amount, and the reflected light amount change measuring unit 54 corrects the waveform plotted as a time series of measurement values ​​so that it becomes a waveform in accordance with the amount of phase shift of the fringe pattern 36 based on the pulse signal.

[0149] According to this embodiment, it is possible to accurately measure the change in the amount of reflected light at each pixel 45 without being affected by variations in the trapezoidal drive of the actuator 34 or the image switching timing of the projector, thereby improving the accuracy of calculating the initial phase φ of each pixel 45 and the height of each point on the object to be measured corresponding to each pixel 45.

[0150] (8) The additive manufacturing apparatus 1 according to the eighth aspect includes any one of the measuring devices 9 of (1) to (7). The apparatus is equipped with a measuring device, a stage 5 having a modeling surface on which the model is layered, a powder supply unit 6 that supplies powder onto the modeling surface, and a head 8 that irradiates a beam onto the powder on the modeling surface to sinter it.

[0151] According to this embodiment, it is possible to manufacture a model with high precision while measuring the shapes of the modeling surface and the powder bed 6b. [Explanation of symbols]

[0152] 1...Additive manufacturing device, 2...Model, 3...Chamber, 4...Cylinder, 5...Stage, 5a...Modeling surface, 6...Powder supply unit, 6a...Powder, 6b...Powder bed, 7...Coater, 8...Head, 8a...Beam, 9...Measuring device, 11...Measurement object, 13...Image, 20...Modeling control unit, 21...Stage control unit, 22...Powder supply control unit, 23...Coater control unit, 24...Head control unit, 30...Projection unit, 31...Case, 32...Light source, 33...Mask, 33a...Substrate, 33b...Striped pattern, 34...Actuator, 35...Projection Lens, 36...fringe pattern, 37...signal output unit, 40...imaging unit, 41...camera, 42...light receiving lens, 43...camera case, 44...imager, 44a...imager surface, 45...pixel, 45a...pixel, 50...information processing unit, 51...projection control unit, 52...imaging control unit, 53...memory unit, 54...reflected light amount change measurement unit, 55...phase calculation unit, 56...height calculation unit, 57...surface shape calculation unit, O1...optical axis, O2...optical axis, P1...measurement point, PA...camera base point, PB...projection base point, L1...base line, L2...camera line of sight

Claims

1. a projection unit that projects a fringe pattern onto a surface of the object to be measured; an imaging unit that images the fringe pattern projected onto the surface of the object to be measured; an information processing unit that processes information of the fringe pattern captured by the imaging unit and measures the shape of the object to be measured; Equipped with the fringe pattern is a wave pattern having a down edge where the amount of reflected light changes from a maximum value to a minimum value or a rising edge where the amount of reflected light changes from a minimum value to a maximum value, the imaging unit has an imager that acquires the amount of reflected light at each point on the surface of the object to be measured, The information processing unit a projection control unit that controls the projection unit so that the phase of the fringe pattern moves in a predetermined direction; a reflected light amount change measuring unit that measures a change in the amount of reflected light at each point on the surface of the object corresponding to each pixel of the imager, which is caused by a phase change of the fringe pattern, based on the amount of reflected light acquired for one cycle of the waveform pattern by changing the phase of the fringe pattern; a phase calculation unit that detects the down edge or the rising edge from the time series of the measurement values ​​of the reflected light amount at each pixel to detect a period origin of the fringe pattern, and calculates an initial phase of each pixel based on the detected period origin; a height calculation unit that calculates the height of each point on the surface of the object corresponding to each pixel based on the initial phase of each pixel; having Measuring equipment.

2. The projection unit a light source that irradiates light toward the object to be measured; a mask that transmits light emitted from the light source and generates the fringe pattern; an actuator for moving the mask; and the projection control unit controls the actuator so that the mask moves in the predetermined direction. The measurement device according to claim 1 .

3. the projection unit is a projector, the projection control unit outputs a control signal to the projection unit so as to project a projection pattern image in which the phase of the fringe pattern is shifted in a predetermined direction at predetermined time intervals. The measurement device according to claim 1 .

4. the fringe pattern is a sawtooth pattern; the phase calculation unit detects the down edge or the rising edge as a period origin of the sawtooth wave pattern, and measures an initial phase of each pixel from the position of the period origin in the time series of the measurement values; The measuring device according to any one of claims 1 to 3.

5. the reflected light amount change measuring unit corrects the measurement values ​​that deviate from a predetermined ideal straight line of the reflected light amount change or a straight line that is an approximate straight line obtained from the time series of the measurement values ​​by moving them onto the straight line. The measuring device according to claim 4.

6. the fringe pattern is a rectangular wave pattern consisting of a section where the amount of reflected light is maximum and a section where the amount of reflected light is minimum, the phase calculation unit measures the initial phase of each pixel based on the elapsed time from a first edge, which is a down edge or a rising edge, that is first detected in the time series of measurement values, to a second edge, which is a rising edge or a down edge, that is next detected, and based on the proportion of a section in one cycle of the rectangular wave pattern where the amount of reflected light is maximum or minimum. The measuring device according to any one of claims 1 to 3.

7. the projection unit further includes a signal output unit that outputs a pulse signal in response to a phase shift of the fringe pattern, the information processing unit further includes an imaging control unit that, when detecting from the pulse signal that the phase of the fringe pattern has shifted by a predetermined amount, controls the imaging unit to image the fringe pattern; the reflected light amount change measuring unit corrects a waveform obtained by plotting a time series of the measurement values ​​so that the waveform corresponds to an amount of phase shift of the fringe pattern based on the pulse signal. The measurement device according to claim 6.

8. The measurement device according to any one of claims 1 to 3; a stage having a modeling surface on which an object is layer-by-layer manufactured; a powder supply unit that supplies powder onto the modeling surface; a head that irradiates a beam onto the powder on the building surface to sinter it; Equipped with Additive manufacturing equipment.

Images