Measurement device and additive manufacturing device

Abstract

This measurement device comprises a projection unit, an imaging unit, and an information processing unit. A fringe pattern in this device is a waveform pattern having down edges or rise edges. The information processing unit includes: a projection control unit that controls the projection unit so that the phase of the fringe pattern moves; a reflected-light-amount change measurement unit that measures, using the pixels of an imager, changes in the amounts of reflected light at points on the surface of an object under measurement that accompany phase changes of the fringe pattern; a phase calculation unit that detects the down edges or the rise edges from a time series of the measured values of the amounts of reflected light at the points on the surface of the object under measurement to detect the origin of the period of the fringe pattern, and that calculates initial phases of the pixels on the basis of the detected origin of the period; and a height calculation unit that, on the basis of the phases of the pixels, calculates the heights of the points on the surface of the object under measurement that correspond to said pixels.

Description

Measuring equipment and additive manufacturing equipment

[0001] This application claims priority to Japanese Patent Application No. 2024-031014, filed on March 1, 2024, the contents of which are incorporated herein by reference.

[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 Literature 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 model. The additive manufacturing device detects irregularities in the model based on data acquired by capturing an image of the fringe pattern projected onto the model.

[0004] Japanese Patent Application Laid-Open No. 2019-173103

[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 accuracy of the phase measurement at the observation point. 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.

[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.

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

[0011] FIG. 1 is a configuration diagram of an additive manufacturing apparatus according to a first embodiment of the present disclosure. FIG. 2 is a functional block diagram of a manufacturing control unit according to a first embodiment of the present disclosure. FIG. 3 is a configuration diagram of a projection unit according to a first embodiment of the present disclosure. FIG. 4 is a schematic diagram of a fringe pattern according to a first embodiment of the present disclosure. FIG. 5 is a schematic diagram of a fringe pattern according to a first embodiment of the present disclosure. FIG. 6 is a configuration diagram of an imaging unit according to a first embodiment of the present disclosure. FIG. 7 is a schematic diagram showing a measurement method according to a first embodiment of the present disclosure. FIG. 8 is a functional block diagram of an information processing unit according to a first embodiment of the present disclosure. FIG. 9 is a flowchart showing a procedure for additive manufacturing according to a first embodiment of the present disclosure. FIG. 10 is a flowchart showing a procedure for a measurement method according to a first embodiment of the present disclosure. FIG. 11 is a flowchart showing a procedure for measuring the height of a measurement object according to a first embodiment of the present disclosure. FIG. 12 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 a first embodiment of the present disclosure. FIG. 13 is a diagram showing a change in the amount of reflected light at one measurement point according to a first embodiment of the present disclosure. FIG. 14 is a schematic diagram of a fringe pattern according to a second embodiment of the present disclosure. FIG. 15 is a diagram showing a change in the amount of reflected light at one measurement point according to a second embodiment of the present disclosure. FIG. 16 is a configuration diagram of an additive manufacturing apparatus according to a third embodiment of the present disclosure. FIG. 17 is a diagram showing 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. Fig. 10 is a diagram showing an example of a change in reflected light amount after correction at one measurement point according to a third embodiment of the present disclosure. Fig. 11 is a schematic diagram of a fringe pattern according to a fourth embodiment of the present disclosure. Fig. 12 is a schematic diagram of a fringe pattern according to a fifth embodiment of the present disclosure. Fig. 13 is a schematic diagram of a fringe pattern according to a sixth embodiment of the present disclosure. Fig. 14 is a hardware configuration diagram according to an embodiment of the present disclosure.

[0012] First Embodiment An additive manufacturing apparatus 1 according to a first embodiment of the present disclosure will be described below with reference to FIGS. 1 to 13. Hereinafter, one horizontal direction will be referred to as the X direction, and the horizontal direction perpendicular to the X direction will be referred to as the Y direction. The up-down direction will be referred to as the Z direction. The Z direction is perpendicular to the X and Y directions.

[0013] 1 manufactures 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 manufacturing 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 houses a cylinder 4, a stage 5, a powder supply unit 6, and a coater 7. 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 in the top of the housing 3a. In FIG. 1, an example configuration is shown in which the projection window 3c and the imaging window 3d face each other in the horizontal direction with the beam window 3b in between, but this is not limited to this. 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. The 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 model 2 is layer-by-layer manufactured on the modeling surface 5a. The stage 5 is provided so as to be movable in the up and down direction along the cylinder 4. In other words, the height of the modeling surface 5a can be changed.

[0017] (Powder Supply Unit) 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 modeling surface 5a, thereby forming a powder bed 6b on the modeling 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 and causes the powder supply unit 6 to supply powder 6a onto the modeling surface 5a. The coater control unit 23 controls the coater 7 and causes the coater 7 to level the powder 6a on the modeling surface 5a to form a powder bed 6b. The head control unit 24 controls the head 8 and causes the head 8 to irradiate the beam 8a onto the powder bed 6b on the modeling surface 5a.

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

[0022] (Projection Unit) The projection unit 30 is disposed outside the chamber 3. The projection unit 30 is disposed above the printing surface 5a across the 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) in an area including the surface of the object to be measured 11.

[0023] As shown in FIG. 3, the projection unit 30 includes a light source 32, a mask 33, an actuator 34, and a projection lens 35.

[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 multiple 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 multiple 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 transmittance values ​​Max and Min 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 33 b may gradually decrease from a maximum value Max to a 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 falls back to the maximum value Max at the cycle origin of the next cycle.

[0026] (Actuator) The actuator 34 moves the mask 33 in the second direction (Y direction in FIG. 4 ), which is the arrangement direction of the stripe pattern 33 b. 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] (Arrangement of Mask and Projection Lens) The mask 33 is inclined with respect to the optical axis O1 of the light source 32. That is, the mask 33 is arranged 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 arranged 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 its 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 disposed outside the chamber 3. The imaging unit 40 is disposed above the printing surface 5a across the imaging window 3d. To prevent the imaging unit 40 from interfering with the head 8, the projection unit 30 is disposed at an angle relative to the printing surface 5a, offset from directly above the printing surface 5a. While FIG. 1 illustrates an exemplary configuration in which the imaging unit 40 is disposed horizontally opposite the projection unit 30 across the head 8, this is not limiting. The positional relationship between the head 8, the projection unit 30, and the imaging unit 40 may be changed to match 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 via 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 image capturing unit 40 continuously captures images of the fringe pattern 36 projected by the projection unit 30. As shown in FIG. 6 , the image capturing 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 to be measured 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 to be measured 11.

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

[0034] (Arrangement of Imager and Light-Receiving Lens) 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 Section) The information processing section 50 processes information on the fringe pattern 36 captured by the imaging section 40, and calculates the shape of the measurement object 11. As shown in Fig. 8 , the information processing section 50 has the functions of a projection control section 51, an imaging control section 52, a memory section 53, a reflected light amount change measurement section 54, a phase calculation section 55, a height calculation section 56, and a surface shape calculation section 57.

[0036] (Projection Control Unit) The projection control unit 51 controls the projection unit 30 to project the 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. Note that 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 to be measured 11 .

[0038] (Memory unit) 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 measured object 11 acquired by the height calculation unit 56 described later.

[0039] (Reflected light amount change measuring 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 section 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 section 54 .

[0041] (Height Calculation Unit) 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 Unit) The surface shape calculation unit 57 calculates the surface shape of the object 2 by aggregating the heights of each point on the surface of the object 11. For example, the surface shape calculation unit 57 specifies the surface shape of the object 11 by plotting each point on the surface of the object 11 in a virtual space. The surface shape of the object 11 here means the uneven shape of the surface of the object 11 expressed in terms of height from the printing surface 5 a.

[0043] (Additive Manufacturing Procedure) The additive manufacturing procedure will be described below with reference to the flowchart in FIG. 9. 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 in the Z direction on the build surface 5a. In this way, the object 2 is layer-by-layer manufactured on the manufacturing surface 5a.

[0044] (Procedure of Measurement Method) Below, with reference to the flowchart in Fig. 10, the procedure of the method for measuring the shape of the object to be measured 11 (for example, the molded object 2 or the powder bed 6b) using the measurement device 9 will be described. In this embodiment, the measurement device 9 calculates the shape of the object to be measured 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). Below, with reference to the flowchart in Fig. 11, the procedure of step S21 will be described in detail.

[0045] As shown in Figure 7, the procedure of step S21 will be described using as an example the case of calculating the height of a measurement point P1 on the surface of the object to be measured 11 corresponding to one pixel 45a of the imager 44. 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 the base line L1. The line passing through the camera base point PA and pixel 45a is defined as the camera line of sight line L2. The 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 measurement 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 images of 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 45 a is acquired n times. The measured values ​​of the amount of light reflected by the pixel 45 a are stored in the storage unit 53 .

[0048] After step S32, the reflected light amount change measuring unit 54 measures the measured value I １ ~I 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. １ ~I ８ 13 shows an example of some of the measured values ​​of the reflected light amount 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 measured values ​​I of the reflected light amount of the pixel 45a at each time on a graph with time on the horizontal axis and the reflected light amount on the vertical axis. １ ~I 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 is equal to the maximum reflected light amount I between the last measured value of one period and the first measured value of the next period. Ｈ From the minimum reflected light amount I Ｌ Therefore, the maximum reflected light amount I Ｈ From the minimum reflected light amount 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. ８ 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 associated with 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 line LN using the least squares method from the time series data in the middle of the measurement period. Note that since the approximated 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 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 value so that it fits the set line LN. In the example of FIG. 13 , a deviation occurs in the time axis direction during the acceleration / deceleration section and deceleration section of the actuator 34 compared to the constant velocity section. Therefore, the measurement value I that deviates in the time axis direction from the line LN is １ ~I ３ , I ｎ－２ ~I ｎis corrected in the time axis direction to fit the straight line LN. In this way, the reflected light amount 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, etc. 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 reflected light amount I from the waveform obtained by plotting the amount of reflected light of the pixel 45a. Ｈ From the minimum reflected light amount I Ｌ Since the sawtooth wave pattern has a simple increase (or a simple decrease) in the amount of reflected light, the phase calculation unit 55 calculates the phase I from the waveform amplitude and the initially acquired measurement value I of the amount of reflected light. １ The initial phase φ of the pixel 45a can be obtained from

[0052] After step S34, the height calculation unit 56 calculates the height of the measurement point P1 corresponding to pixel 45a based on the initial phase φ of 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 pixel 45a (the angle θB formed between the baseline L1 and a 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 Figure 13, the azimuth angle θB of the measurement point P1 corresponding to 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 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 formed 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 on 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 11 corresponding to each pixel 45 calculated in step S21 to calculate the surface shape of the object 11 (step S22). For example, the surface shape calculation unit 57 specifies the surface shape of the object 11 by plotting each point on the surface of the object 11 in a virtual space. With the above procedure, the calculation of the shape of the object 11 is completed.

[0055] (Effects) The measuring device 9 and additive manufacturing device 1 of this embodiment provide the following effects. This embodiment 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 object to be measured 11. The imaging unit 40 captures an image of the fringe pattern 36 projected onto the surface of the object to be measured 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 object to be measured 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 object to be measured 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 during the change in the amount of reflected light, making it difficult to accurately detect 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 easily 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 measurement 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 the 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-described 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 a down edge or a 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 described above, the sawtooth wave pattern has a maximum reflected light amount I at the origin of the period. Ｈ From the minimum reflected light amount I Ｌ to, or minimum reflected light amount I Ｌ Maximum reflected light amount I Ｈ The 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, if the amount of phase shift 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 the projection pattern image of the projector, causing variations in the measurement values, the measurement device 9 can correct this. By using the time series of measurement values ​​corrected 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 assigned the same reference numerals, and detailed description thereof 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 composed 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 section 1 and section C2 within one cycle may be different, and may be set arbitrarily. The ratios of sections C1 and C2 within 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 rectangular 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] (Procedure of Measurement Method) The procedure of the measurement method in this embodiment is the same as that in the first embodiment (FIG. 10). However, a 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 value I １ ~I ｎ 15, the reflected light amount change measuring unit 54 plots the measured value I 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. １ ~I ｎ In this embodiment, since the fringe pattern 36 is a rectangular wave pattern, the maximum reflected light amount I is plotted as in the example of FIG. 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 from 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 to 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 cycle of the rectangular wave pattern. Ｈ The section in which the minimum reflected light amount I Ｌ The initial phase φ of the pixel 45a is measured based on the ratio of the duration of the period in which the pixel 45a continues.

[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 ｔ２ The phase calculation unit 55 calculates the elapsed time dt1 from the first image capture time t0 to the time t1 when the first down edge is detected, and the elapsed time dt2 from the time t1 to the time t2 when 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 Therefore, the phase calculation unit 55 calculates the time corresponding to one period of the rectangular 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 period C1 or 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 on the time axis of this square wave pattern is the time measured by dt2×2 going back from 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 amount I ＨThe 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 the 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. With the above procedure, the calculation of the height of the measurement point P1 of the object to be measured 11 corresponding to one pixel 45a is completed. Similar processes are performed for the other pixels 45 of the imager 44.

[0074] (Effects) The measuring device 9 and additive manufacturing device 1 of this embodiment provide the following 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 a first edge, which is a down edge or rising edge, that is first detected in the time series of measurement values ​​to a second edge, which is a rising edge or 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 measured. This can lead to measurement errors in the amount of reflected light, reducing the accuracy of phase calculation. 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 influence 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 are given the same reference numerals, and detailed description thereof will be omitted.

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

[0078] (Signal Output Unit) The signal output unit 37 outputs a pulse signal in response to 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 Section) In the information processing section 50 according to this embodiment, the functions of the imaging control section 52 and the reflected light amount change measuring section 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 Measuring 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 measuring 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] (Procedure of Measurement Method) The procedure of the measurement method in this embodiment is the same as that in the second embodiment. However, a part of the processing in the procedure of step S21 (FIG. 11) for calculating the height of each point on the surface of the measurement object 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, and when the imaging control unit 52 receives a pulse signal indicating 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 value I １ ~I ｎ Based on this, the change in the amount of reflected light is measured (step S33).

[0089] FIG. 17 shows, as an example, a pulse signal outputted every time the mask 33 moves, and a measurement value I of the amount of reflected light measured by the pixel 45a in response to the pulse signal. １ ~I ｎ As 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 the output interval of the pulse signal is longer in the acceleration section and deceleration section than in the constant velocity section. Therefore, as shown in (a) of FIG. 17, the measured value I １ ~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 would 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 deviation 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 movement 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 rectangular 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 represents 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 represents 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 represents the amount of deviation from the period origin. The phase calculation unit 55 calculates the initial phase φ in the same manner as in the second embodiment ( FIG. 15 ), substituting time for the movement amount. 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 in steps S34 and S35 are the same as those in the second embodiment. Through the above procedure, measurement of the height of measurement point P1 of the object 11 corresponding to one pixel 45a is completed. Similar processes are performed for the other pixels 45 of the imager 44.

[0091] (Effects) The measuring device 9 and additive manufacturing device 1 of this embodiment provide the following effects. In this embodiment, the projection unit 30 further includes a signal output unit 37 that outputs a pulse signal in accordance with a shift in the phase of the fringe pattern 36. The information processing unit 50 further includes an imaging control unit 52 that controls the imaging unit 40 to image the fringe pattern 36 when it detects from the pulse signal that the phase of the fringe pattern 36 has shifted a predetermined amount. The reflected light amount change measuring unit 54 of the information processing unit 50 corrects the waveform obtained by plotting 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.

[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 measured object 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 denoted by the same reference numerals, and detailed description thereof will be omitted.

[0094] (Fringe Pattern) As shown in FIG. 19 , the fringe pattern 36 according to 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. Using 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 of RGB. 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] (Procedure of Measurement Method) The procedure of the measurement method in this embodiment is the same as that in the first embodiment (FIG. 10). However, a 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 the image of the first waveform W1, and a G image obtained by capturing only the green wavelength as the 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 period of the second waveform W2 (sawtooth wave) the waveform in which the initial phase φ2 is 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 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 belongs to.

[0099] After step S34, the height calculation unit 56 calculates the height of the measurement point P1 corresponding to pixel 45a based on the period and initial phase φ2 of the second waveform at pixel 45a (step S35). Using a waveform with a shorter period improves measurement accuracy in the height direction. However, shortening the period can result in a height error equivalent to one period if the height of the projected waveform at measurement point P1 corresponding to pixel 45a shifts by more than one period (2π). However, in this embodiment, the initial phase φ1 of the first waveform W1 at pixel 45a can be determined based on the initial phase φ1 of the first waveform W1 at pixel 45a. As described in the first embodiment, the short-period second waveform W2 (sawtooth wave pattern) requires a pattern shift of one period before the initial phase φ2 of pixel 45a can be calculated. On the other hand, by using a sinusoidal wave pattern for the first waveform W1, the initial phase φ1 can be calculated by simply moving the first waveform W1 slightly (by one period of the short-period second waveform W2). This allows for a wider measurement range in the height direction than in the first embodiment, while still moving the actuator 34 by the same amount 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 the second waveform W2 has 20 periods throughout the entire fringe pattern 36, the phase of the first waveform W1 can be calculated with an accuracy of approximately 360° / 20 = ±6.5°. By combining the first waveform W1 and the second waveform W2 in this manner, the height can be calculated accurately even in areas where the height changes 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 measurement object 11 corresponding to one pixel 45a. Similar processing is performed for the other pixels 45 on the imager 44.

[0101] (Effects) The measuring device 9 and additive manufacturing device 1 of this embodiment provide the following 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 changes 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 changes over a shorter period than that of the first waveform W1. The reflected light amount change measuring unit 54 measures the changes in the amount of reflected light of the first waveform W1 and the second waveform W2 at each point on the surface of the object to be measured 11 corresponding to each pixel 45 of the imager 44 that accompany the phase change 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, φ2 of the first waveform W1 and the second waveform W2 of each pixel 45 from the time series of the measured values ​​of the reflected light amount 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 photograph 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, the 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. In the fifth embodiment, the fringe pattern of the fourth embodiment is changed. Components common to the fourth embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

[0106] 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 along a predetermined direction (Y direction) of the fringe pattern 36, and a descending pattern W1b in which the amount of reflected light gradually decreases. 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 imaging 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] (Procedure of measurement method) The procedure of the measurement method in this embodiment is the same as that in the fourth embodiment. However, among the processes in the procedure of step S21 (FIG. 11) for measuring the height of each point on the surface of the measurement object 11, a part of the processes in 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 of the rising pattern W1a (R image), the image of the falling pattern W1b (B image), and the image of the second wavelength (G image) of the first waveform W1 captured by the imaging unit 40 (step S33).

[0109] 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 for each wavelength of pixel 45a (step S34). First, the phase calculation unit 55 calculates the position (initial phase φ1) of pixel 45a across 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) of the first waveform W1. The phase calculation unit 55 also calculates the initial phase φ2 of pixel 45a on the second waveform W2 (sawtooth wave) based on the change in the amount of reflected light in the multiple G images. Furthermore, the phase calculation unit 55 uses the initial phase φ1 of the first waveform W1 to identify which cycle of the multiple second waveforms W2 (sawtooth waves) the waveform at which the initial phase φ2 was detected is. 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] In the sine wave pattern, the maximum reflected light amount 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, the ascending pattern W1a and the 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 at 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). Through the above procedure, measurement of the height of the measurement point P1 of the object 11 corresponding to one pixel 45a is completed. Similar processing is performed for the other pixels 45 of the imager 44.

[0112] (Effects) The measuring device 9 and additive manufacturing device 1 of this embodiment have the following effects: In this embodiment, the first waveform W1 of the fringe pattern 36 is made up 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 described above, in the sinusoidal wave pattern, the maximum reflected light amount I Ｈ and minimum reflected light amount I Ｌ Around 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°) and the minimum value (phase 270°) are 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 sum (Dr+Db) of the reflected light amounts of the ascending pattern W1a and the descending pattern W1b is a constant value, so by normalizing using this value, the phase can be accurately detected regardless of changes in the reflectance of the object 11 to be measured or the ambient temperature.

[0114] Sixth Embodiment Next, a sixth embodiment will be described with reference to Fig. 21. The sixth embodiment is a modification of 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 formed by superimposing a signal representing each period on a portion of the waveform of each period. The fringe pattern 36 according to this embodiment does not combine multiple types of waveforms, as in the fourth and fifth embodiments, but includes only one type of waveform. While FIG. 21 illustrates 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 illustrates 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] (Procedure of Measurement Method) The procedure of the measurement method in this embodiment is the same as that in the fourth embodiment. However, among the processes in the procedure 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 processes in 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 from 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 plotting the time series of the measured values. The maximum reflected light amount I before and after this period origin is calculated. Ｈ and the minimum reflected light amount I Ｌ The waveform amplitude of the sawtooth wave pattern can be determined from the waveform amplitude and the initially acquired measurement value I of the amount of reflected light, since the sawtooth wave pattern has a simple increase (or a simple decrease) in the amount of reflected light. １ The initial phase φ of pixel 45a can be calculated from the signal. The phase calculation unit 55 analyzes the signal included in the time series of measurement values ​​to determine the period of the waveform measured by pixel 45a. 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. The measured signal portion can be corrected to reduce the reflected light amount by a certain percentage, thereby restoring the original waveform without any superimposed signal. For example, when a sine wave pattern is used, the initial phase φ can be calculated more accurately by removing the change in the reflected light amount due to the superimposed signal and restoring the original sine wave pattern. In other words, the fringe pattern 36 according to this embodiment is characterized in that the reflected light amount (transmittance) of the signal portion is increased by a certain percentage from the original waveform, which facilitates the restoration of the original waveform pattern and enables the initial phase φ to be calculated with high accuracy.

[0119] Also, for example, suppose that at the start of imaging, a waveform is observed in pixel 45a starting halfway through 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 determines 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 using the azimuth angle θn of the period origin of the period number read from the signal and the initial phase φ of pixel 45a, as follows: θB = θn + φ. The method for calculating the height of measurement point P1 corresponding to pixel 45a using the azimuth angle θB is the same as in the first embodiment. Through the above procedure, the calculation of the height of measurement point P1 of the object 11 corresponding to one pixel 45a is completed. Similar processing is performed for the other pixels 45 of the imager 44.

[0121] (Actions and Effects) The measuring device 9 and additive manufacturing device 1 of this embodiment provide the following actions and 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 large-scale integrated circuit (LSI) such as a programmable logic device (PLD) in addition to or instead of the above configuration. Examples of PLDs include programmable array logic (PAL), generic array logic (GAL), complex programmable logic device (CPLD), and field programmable gate array (FPGA). In this case, some or all of the functions realized 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) Although the embodiments of the present disclosure have been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes and the like within the scope that does not deviate from the gist of the present disclosure are also included.

[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 this is not limitative. 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 unit 40 has been described, but this is not limitative. The imaging unit 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 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 a 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 of the imager 44 due to a 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 a 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 measurement device 9 according to the second aspect is the measurement 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, since 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, the projection unit 30 can 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 makes it possible to reduce the manufacturing costs and introduction costs of the measuring device 9.

[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 aspect, it is easy to accurately detect the period origin based on the abrupt 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 aspect, when the phase shift amount of the fringe pattern 36 is not constant due to the influence of changes in the moving speed of the actuator 34 or variations in the timing of image switching 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 measurement 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 where the amount of reflected light is at its maximum and a section C2 where 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 where the amount of reflected light is at its maximum or the proportion of the section C2 where the amount of reflected light is at its minimum in one cycle of the rectangular wave pattern.

[0147] According to this aspect, 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 easily than with a sine wave pattern or a sawtooth wave pattern, making it possible to manufacture the mask 33 more easily and with higher accuracy.

[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 aspect, 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 measured object corresponding to each pixel 45.

[0150] (8) The eighth aspect of the additive manufacturing apparatus 1 includes a measuring device 9 selected from any one of (1) to (7), a stage 5 having a manufacturing surface on which an object is additively manufactured, a powder supply unit 6 that supplies powder onto the manufacturing surface, and a head 8 that irradiates a beam onto the powder on the manufacturing surface to sinter it.

[0151] According to this aspect, it is possible to manufacture a molded object with high precision while measuring the shapes of the molding surface and the powder bed 6b.

[0152] According to the measuring device and additive manufacturing device of the present disclosure, it is possible to improve measurement performance.

[0153] 1...Layered manufacturing apparatus, 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...storage 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 measurement system comprising: a projection unit that projects a fringe pattern onto the 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, and 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 comprises: a projection control unit that controls the projection unit so that the phase of the fringe pattern moves in a predetermined direction; and a reflected light amount change measurement unit that measures the change in the amount of reflected light at each point on the surface of the object to be measured corresponding to each pixel of the imager due to the 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 a time series of measurement values ​​of the amount of reflected light at each pixel to detect a periodic origin of a fringe pattern, and calculates an initial phase of each pixel based on the detected periodic origin; and a height calculation unit that calculates a height of each point on the surface of the object to be measured that corresponds to each pixel based on the initial phase of each pixel.

2. The measurement device described in claim 1, wherein the projection unit has: a light source that irradiates light toward the object to be measured; a mask that transmits the light irradiated from the light source and generates the fringe pattern; and an actuator that moves the mask, and the projection control unit controls the actuator so that the mask moves in the specified direction.

3. The measurement device according to claim 1, wherein the projection unit is a projector, and 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.

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

5. The measurement device according to claim 4, wherein the reflected light amount change measurement unit corrects 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 a time series of measurement values ​​by moving them onto the straight line.

6. A measurement device according to any one of claims 1 to 3, wherein 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, and 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 rising edge that is first detected in the time series of measurement values, to a second edge, which is a rising edge or down edge that is next detected, and the proportion of sections in one cycle of the rectangular wave pattern where the amount of reflected light is maximum or minimum.

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

8. An additive manufacturing device comprising: the measuring device according to any one of claims 1 to 3; 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.

Images