Three-dimensional measuring device

Abstract

The three-dimensional measurement device (101) includes: one or more light source units (102) that irradiate the object to be measured (SA) with measurement light (105) having a prescribed pattern; one or more imaging units (103) that image the object to be measured (SA) irradiated with the measurement light (105); and a measurement unit (104) that measures the three-dimensional shape of the object to be measured (SA) based on the imaging result of the imaging unit (103). The light source unit (102) is composed of an S-iPMSEL (1) that oscillates at M points.

Description

Technical Field

[0001] The present invention relates to a three-dimensional measurement device. Background Art

[0002] As an existing three-dimensional measurement method, there is, for example, the method described in U.S. Patent Application Publication No. 2008 / 0240502 (Patent Document 1). In the method of Patent Document 1, a random dot pattern is irradiated onto an object to be measured, and two cameras respectively image the dot patterns at the same position. Then, based on the parallax of the two dot patterns, three-dimensional measurement of the object to be measured is performed according to the principle of triangulation.

[0003] In addition, for example, the method described in Japanese Unexamined Patent Application Publication No. 2011-242178 (Patent Document 2) is a measurement method using the phase shift method. In the method of Patent Document 2, a reference flat plate having a reference surface with a projected lattice pattern is prepared, and the reference flat plate is moved parallel in the normal direction by a workbench. Images of the lattice pattern projected onto the reference surface and the lattice pattern projected onto the object to be measured are imaged, and the spatial coordinates of the object to be measured are calculated using a table that correlates the phase of the lattice pattern with the spatial coordinates. Summary of the Invention

[0004] In the method of Patent Document 1 described above, a projector is used as a light source, and in the method of Patent Document 2, an LED array is used as a light source. Therefore, there are problems such as the three-dimensional measurement device becoming larger. As an imaging device, for example, an ultra-small camera with a size of 1 mm square or less has been developed. In order to miniaturize the entire three-dimensional measurement device, it is important to miniaturize the light source. It is considered that if the entire three-dimensional measurement device can be miniaturized, it can be applied to uses such as oral examination, endoscopic examination, examination of narrow parts such as the inside of a tube or the gap between walls, examination of furniture or devices under the floor, etc., or a handheld three-dimensional measurement device can be constructed. In addition, when the light source is applied to a three-dimensional measurement device, from the viewpoint of improving measurement accuracy, a light source that suppresses noise or distortion of the output light is preferred.

[0005] The present invention was created to solve the above technical problems, and its object is to provide a three-dimensional measurement device that expands the application range through miniaturization of the device and improves measurement accuracy.

[0006] A three-dimensional measurement device according to an aspect of the present invention includes: one or more light source units that irradiate an object to be measured with measurement light having a specified pattern; one or more imaging units that image the object to be measured irradiated with the measurement light; and a measurement unit that measures the three-dimensional shape of the object to be measured based on the imaging result of the imaging unit, wherein the light source unit is composed of an S-iPMSEL oscillating at M points.

[0007] In this three-dimensional measurement device, the light source unit is composed of an S-iPMSEL oscillating at M points. The S-iPMSEL includes a phase modulation layer having a basic layer and a plurality of different refractive index regions with refractive indices different from that of the basic layer. The centroid positions of the respective different refractive index regions deviate from the lattice point positions of an imaginary square lattice according to the output light image. The S-iPMSEL is formed in a size such as that of a needle tip, and can output a light image of a two-dimensional pattern in a direction perpendicular to the main surface of the substrate provided with the phase modulation layer or in a direction inclined with respect to the main surface. Therefore, by using the S-iPMSEL as the light source, miniaturization of the entire three-dimensional measurement device can be achieved, and the application range of the device can be expanded. In addition, by using the S-iPMSEL oscillating at M points, output of the 0th-order light (diffraction wave component not phase-modulated) different from the desired light image of the two-dimensional pattern can be eliminated. Thereby, measurement light of a pattern without noise or distortion caused by the 0th-order light can be irradiated onto the object to be measured, and improvement in measurement accuracy can be achieved.

[0008] Alternatively, the three-dimensional measurement device may include a single light source unit and a plurality of imaging units. The specified pattern of the measurement light is a periodic pattern composed of any one of a dot pattern, a bar pattern, and a lattice pattern. The measurement unit measures the three-dimensional shape of the object to be measured based on the active stereo method using the periodic pattern. In this case, three-dimensional measurement using an image with less texture and three-dimensional measurement in a dark area can be performed.

[0009] The three-dimensional measurement device includes the single light source unit and a plurality of imaging units. The specified pattern of the measurement light is a random dot pattern. The measurement unit measures the three-dimensional shape of the object to be measured based on the active stereo method using the random dot pattern. In this case, by using a random dot pattern instead of a periodic dot pattern, misidentification when imaging the same point of the dot pattern by different imaging units can be suppressed.

[0010] Alternatively, the three-dimensional measurement device may include a single light source unit and a plurality of imaging units. The specified pattern of the measurement light is a pattern having a uniform density. The measurement unit measures the three-dimensional shape of the object to be measured based on the active stereo method using the pattern having a uniform density. Since the emitted light from the S-iPMSEL is a laser, speckles may appear in the scattered light. Therefore, even when using a pattern having a uniform density, a random dot pattern is formed in the pattern of the measurement light. By using this random dot pattern, misidentification when imaging the same point of the dot pattern by different imaging units can be suppressed.

[0011] Alternatively, the three-dimensional measurement device may include a plurality of light source units and a single imaging unit. The specified pattern of the measurement light is a Gray code pattern, and the measurement unit measures the three-dimensional shape of the object to be measured based on the triangulation method using the Gray code pattern. The number of patterns of the Gray code pattern only needs to be small relative to the number of pixels of the imaging unit. Therefore, the irradiation of the measurement light with the Gray code pattern can be achieved by a small number of light source units. In the case of using the Gray code, the Hamming distance between adjacent pixels is 1. Even if a bit error occurs when restoring the bit stream, the error converges to 1. That is, in the Gray code, a symbol with a large noise can be obtained.

[0012] Alternatively, the three-dimensional measurement device may include a plurality of light source units and a single imaging unit. The specified pattern of the measurement light is a sine-wave-shaped bar pattern, and the measurement unit measures the three-dimensional shape of the object to be measured based on the phase-shift method using the sine-wave-shaped bar pattern. In this case, by performing height conversion on the measured phase, the height of the object to be measured can be measured at intervals smaller than the pitch of the sine-wave-shaped bar pattern.

[0013] Alternatively, the plurality of light source units respectively output sine-wave-shaped bar patterns with different periods. In the phase-shift method, the discontinuity at 2π in phase becomes a technical problem. In contrast, by using sine-wave-shaped bar patterns with different periods, the discontinuity at 2π in phase can be improved, and high-precision three-dimensional measurement can be achieved with a small number of patterns.

[0014] Alternatively, the three-dimensional measurement device may include a plurality of light source units and a single imaging unit. The specified pattern of the measurement light is a sine-wave-shaped bar pattern, and the measurement unit measures the three-dimensional shape of the object to be measured based on the sampling Moiré method using the sine-wave-shaped bar pattern. In this case, high-precision three-dimensional measurement can be achieved with an even smaller number of patterns.

[0015] Alternatively, the three-dimensional measurement device may include a plurality of light source units and a single imaging unit. The specified pattern of the measurement light is an overlapping pattern in which a sine-wave-shaped bar pattern and a random dot pattern are overlapped, and the measurement unit measures the three-dimensional shape of the object to be measured based on the phase-shift method using the overlapping pattern. In the phase-shift method, the discontinuity at 2π in phase becomes a technical problem. In contrast, by using the random dot pattern, the discontinuity at 2π in phase can be improved, and high-precision three-dimensional measurement can be achieved with a small number of patterns.

[0016] Alternatively, the three-dimensional measurement device may include a plurality of light source units and a single imaging unit. The specified pattern of the measurement light includes a sine-wave-shaped bar pattern and a Gray code pattern, and the measurement unit measures the three-dimensional shape of the object to be measured based on the phase-shift method using the sine-wave-shaped bar pattern and the triangulation method using the Gray code pattern. In the phase-shift method, the discontinuity at 2π in phase becomes a technical problem. In contrast, by using the Gray code, the discontinuity at 2π in phase can be improved, and high-precision three-dimensional measurement can be achieved with a small number of patterns.

[0017] Alternatively, the three-dimensional measurement device may include a plurality of light source units and a plurality of imaging units, the specified pattern of the measurement light may be a sine-wave-shaped bar pattern, and the measurement unit may measure the three-dimensional shape of the object to be measured based on the phase shift method and the active stereo method using the sine-wave-shaped bar pattern. In this case, by performing height conversion on the measured phase, it is possible to measure the height of the object to be measured at intervals smaller than the pitch of the sine-wave-shaped bar pattern. In addition, in the phase shift method, the discontinuity at 2π of the phase becomes a technical problem. In contrast, by combining the active stereo method using a plurality of imaging units, the discontinuity at 2π of the phase can be improved, and high-precision three-dimensional measurement can be achieved with a small number of patterns.

[0018] Alternatively, the light source unit and the imaging unit may be disposed on the surface of the three-dimensional object. In this case, the three-dimensional object on which the light source unit and the imaging unit are disposed can be configured as a probe of the three-dimensional measurement device. By using the three-dimensional object, the respective groups of the light source unit and the imaging unit can be directed in different directions, and thus, three-dimensional shape measurement of the object to be measured can be performed with a large solid angle. In addition, it can be easily applied to uses such as oral examination, endoscopic examination, examination of narrow parts such as the inside of a tube or the gap between walls, examination from under the floor of furniture or devices, etc., or to construct a handheld three-dimensional measurement device. Description of the Drawings

[0019] Figure 1 It is a partial perspective cross-sectional view showing the structure of the S-iPMSEL.

[0020] Figure 2 It is a cross-sectional view showing the stacked structure of the S-iPMSEL.

[0021] Figure 3 It is a top view of the phase modulation layer.

[0022] Figure 4 It is a view showing an enlarged view of the unit constituent region R.

[0023] Figure 5 It is a top view showing an example of applying a substantially periodic refractive index structure in a specific region of the phase modulation layer.

[0024] Figure 6 It is a view for explaining the relationship between the optical image obtained by imaging the output beam pattern of the S-iPMSEL and the rotational angle distribution on the phase modulation layer.

[0025] Figure 7 It is a view for explaining the coordinate transformation from spherical coordinates to coordinates in the XYZ orthogonal coordinate system.

[0026] Figure 8 It is a top view showing the reciprocal lattice space of the phase modulation layer of the S-iPMSEL oscillating at point M.

[0027] Figure 9 It is a conceptual diagram showing the state of adding the in-plane wave number vector and the diffraction vector.

[0028] Figure 10 It is a diagram for schematically explaining the peripheral structure of light.

[0029] Figure 11 It is a diagram conceptually showing an example of the rotation angle distribution φ2(x, y).

[0030] Figure 12 It is a conceptual diagram for explaining the state of removing wave number diffusion from the in-plane wave number vector in a direction and then adding the diffraction vector.

[0031] Figure 13 It is a top view of a phase modulation layer of a modified example.

[0032] Figure 14 It is a diagram showing the positional relationship of different refractive index regions on the phase modulation layer of the modified example.

[0033] Figure 15 It is a schematic diagram showing the structure of the three-dimensional measurement device of the first embodiment.

[0034] Figure 16 It is a diagram showing an example of the periodic pattern used in the first embodiment.

[0035] Figure 17 It is a diagram showing an example of the far-field image of the periodic pattern.

[0036] Figure 18 It is a diagram showing an example of the random dot pattern used in the first embodiment.

[0037] Figure 19 It is a diagram showing an example of the pattern with uniform density used in the first embodiment.

[0038] Figure 20 It is a diagram showing an example of the FFP of the pattern with uniform density.

[0039] Figure 21 It is a schematic diagram showing the structure of the three-dimensional measurement device of the second embodiment.

[0040] Figure 22 It is a diagram showing an example of the Gray code pattern used in the second embodiment.

[0041] Figure 23 It is a diagram showing an example of the sine-wave-shaped bar pattern used in the second embodiment.

[0042] Figure 24This is a diagram showing an example of a sine-wave-shaped matrix pattern used in the second embodiment.

[0043] Figure 25 This is a diagram showing the improvement of discontinuity at a phase of 2π.

[0044] Figure 26 This is a diagram showing an example of a moiré pattern used in the second embodiment.

[0045] Figure 27 This is a diagram showing an example of an overlapping pattern used in the second embodiment.

[0046] Figure 28 This is a diagram showing another example of an overlapping pattern used in the second embodiment.

[0047] Figure 29 This is a schematic diagram showing the structure of the three-dimensional measurement device of the third embodiment.

[0048] Figure 30 This is a schematic perspective view showing an example of the arrangement of the light source unit and the imaging unit.

[0049] Figure 31 This is a schematic perspective view showing another example of the arrangement of the light source unit and the imaging unit.

[0050] Figure 32 This is a perspective view showing an example of the formation of a sine-wave-shaped bar pattern.

[0051] Figure 33 This is a schematic diagram showing an example of a laser with a multi-point pattern and a bar pattern using the laser.

[0052] Figure 34 This is a schematic diagram showing another example of a laser with a multi-point pattern and a bar pattern using the laser.

[0053] Figure 35 This is a schematic cross-sectional view showing an example of the structure of a metal lens. Detailed Embodiment

[0054] Hereinafter, with reference to the accompanying drawings, a preferred embodiment of the three-dimensional measurement device according to one aspect of the present invention will be described in detail.

[0055] The three-dimensional measurement device 101 of the present embodiment is configured to include one or more light source units 102 that irradiate a measurement object SA with measurement light 105 having a predetermined pattern, one or more imaging units 103 that image the measurement object SA irradiated with the measurement light 105, and a measurement unit 104 that measures the three-dimensional shape of the measurement object SA based on the imaging result of the imaging unit 103 (see Figure 15etc.). In addition, the light source unit 102 is composed of an S-iPMSEL (Static-integrable Phase Modulating Surface Emitting Lasers) 1 that oscillates at point M.

[0056] In the three-dimensional measurement device 101, by using the S-iPMSEL 1 configured in the size of a tip as the light source unit 102, the overall size of the device can be miniaturized, and the application range of the device can be expanded. In addition, in the three-dimensional measurement device 101, by using the S-iPMSEL 1 that oscillates at point M, the output of the 0th-order light (diffraction wave component not phase-modulated) different from the optical image of the desired two-dimensional pattern can be eliminated. Thus, the measurement light 105 of a pattern without noise or distortion caused by the 0th-order light can be irradiated onto the object to be measured SA, and the measurement accuracy can be improved.

[0057] [S-iPMSEL that oscillates at point M]

[0058] First, the S-iPMSEL 1 that oscillates at point M will be described. Figure 1 It is a partial perspective cross-sectional view showing the structure of the SiPMSEL. Figure 2 It is a cross-sectional view showing the stacked structure of the S-iPMSEL. In Figure 1 it, an XYZ orthogonal coordinate system is defined with the axis extending in the thickness direction of the S-iPMSEL 1 at the center of the S-iPMSEL 1 as the Z axis.

[0059] The S-iPMSEL 1 is a laser light source that forms a standing wave in the XY-plane direction and outputs a plane wave whose phase is controlled in the Z-axis direction. The S-iPMSEL 1 outputs light images in a direction perpendicular to the main surface 10a of the semiconductor substrate 10 (i.e., the Z-axis direction), or a direction inclined with respect to the main surface 10a, or a two-dimensional arbitrary shape including these two directions.

[0060] As Figure 1 and Figure 2 shown, the S-iPMSEL 1 includes an active layer 12 as a light-emitting part provided on the semiconductor substrate 10, a pair of cladding layers 11 and 13 that sandwich the active layer 12, and a contact layer 14 provided on the cladding layer 13. These semiconductor substrate 10, cladding layers 11, 13, and contact layer 14 are made of compound semiconductors such as GaAs-based semiconductors, InP-based semiconductors, or nitride-based semiconductors. The energy band gap of the cladding layer 11 and the energy band gap of the cladding layer 13 are greater than the energy band gap of the active layer 12. The thickness directions of the semiconductor substrate 10 and each layer 11 to 14 are the same as the Z-axis direction.

[0061] S-iPMSEL1 also includes a phase modulation layer 15 that is optically coupled to the active layer 12. In this embodiment, the phase modulation layer 15 is disposed between the active layer 12 and the cladding layer 13. The thickness direction of the phase modulation layer 15 is consistent with the Z-axis direction. The phase modulation layer 15 can also be disposed between the cladding layer 11 and the active layer 12. As needed, a light guiding layer can also be disposed in at least one of the space between the active layer 12 and the cladding layer 13 and the space between the active layer 12 and the cladding layer 11. The light guiding layer can include a carrier barrier layer for efficiently confining carriers to the active layer 12.

[0062] The phase modulation layer 15 is configured to include a basic layer 15a made of a first refractive index medium and a plurality of different refractive index regions 15b made of a second refractive index medium having a refractive index different from that of the first refractive index medium and existing within the basic layer 15a. The plurality of different refractive index regions 15b include a substantially periodic structure. When the equivalent refractive index of the mode is set to n, the wavelength λ0(=(√2)a×n, where a is the lattice pitch) selected by the phase modulation layer 15 is included in the emission wavelength range of the active layer 12. The phase modulation layer 15 can select the band edge wavelength near the wavelength λ0 in the emission wavelength of the active layer 12 and output it to the outside. The laser incident into the phase modulation layer 15 forms a specified mode corresponding to the configuration of the different refractive index regions 15b within the phase modulation layer 15 and is emitted from the surface of the S-iPMSEL1 to the outside as a laser beam having a desired pattern.

[0063] S-iPMSEL1 also includes an electrode 16 disposed on the contact layer 14 and an electrode 17 disposed on the back surface 10b of the semiconductor substrate 10. The electrode 16 makes an ohmic contact with the contact layer 14, and the electrode 17 makes an ohmic contact with the semiconductor substrate 10. The electrode 17 has an opening 17a. The electrode 16 is disposed in the central region of the contact layer 14. The portion of the contact layer 14 other than the electrode 16 is covered by a protective film 18 (see Figure 2 ). Due to the limitation of the current range, the contact layer 14 not in contact with the electrode 16 can also be removed. The portion of the back surface 10b of the semiconductor substrate 10 other than the electrode 17, including the inside of the opening 17a, is covered by an antireflection film 19. The antireflection film 19 in the region other than the opening 17a can also be removed.

[0064] In the S-iPMSEL1, if a driving current is supplied between the electrode 16 and the electrode 17, recombination of electrons and holes occurs in the active layer 12, and the active layer 12 emits light. The electrons, holes, and light generated in the active layer 12 that contribute to the emission are efficiently confined between the cladding layer 11 and the cladding layer 13.

[0065] The light emitted from the active layer 12 enters the inside of the phase modulation layer 15, forming a specified mode corresponding to the lattice structure inside the phase modulation layer 15. The laser light emitted from the phase modulation layer 15 passes through the opening 17a from the back surface 10b and is directly output to the outside of the S-iPMSEL 1. Alternatively, the laser light emitted from the phase modulation layer 15 is reflected in the electrode 16, and then passes through the opening 17a from the back surface 10b and is output to the outside of the S-iPMSEL 1. At this time, the signal light (measurement light 105) included in the laser light is emitted in an arbitrary two-dimensional direction including a direction perpendicular to the main surface 10a or a direction inclined with respect to the main surface 10a. It is this signal light that forms a desired light image. The signal light is mainly the first-order light and the -1st order light of the laser. The 0th order light of the laser is not output from the phase modulation layer 15 of the present embodiment.

[0066] Figure 3 is a top view of the phase modulation layer 15. As shown in this figure, the phase modulation layer 15 includes a basic layer 15a made of a first refractive index medium and a plurality of different refractive index regions 15b made of a second refractive index medium having a refractive index different from that of the first refractive index medium. In Figure 3 a, a hypothetical square lattice in the XY plane is set for the phase modulation layer 15. One side of the square lattice is parallel to the X axis, and the other side is parallel to the Y axis. A square unit constituent region R centered on the lattice point O of the square lattice is set two-dimensionally over multiple columns along the X axis and multiple rows along the Y axis. If the XY coordinates of each unit constituent region R are defined at the centroid position of each unit constituent region R, these centroid positions coincide with the lattice point O of the hypothetical square lattice. The plurality of different refractive index regions 15b are provided, for example, one by one in each unit constituent region R. The planar shape of the different refractive index region 15b is, for example, a circular shape. The lattice point O may be located outside the different refractive index region 15b or inside the different refractive index region 15b.

[0067] The ratio of the area S of the different refractive index region 15b occupied within one unit constituent region R is called the filling factor (FF). If the lattice pitch of the square lattice is a, the filling factor FF of the different refractive index region 15b is given as S / a 2 . S is the area of the different refractive index region 15b on the XY plane. For example, when the shape of the different refractive index region 15b is a perfect circle, the filling factor FF is given as S = π(d / 2) using the diameter d of the perfect circle 2 . When the shape of the different refractive index region 15b is a square, the filling factor FF is given as S = LA using the length LA of one side of the square 2 .

[0068] Figure 4It is an enlarged diagram showing the unit constituent area R. As shown in the figure, the different refractive index regions 15b each have a center of gravity G. Here, let the angle formed by the vector from the lattice point O toward the center of gravity G and the X-axis be φ(x, y). x represents the position of the x-th lattice point on the X-axis, and y represents the position of the y-th lattice point on the Y-axis. When the rotation angle φ is 0°, the direction of the vector connecting the lattice point O and the center of gravity G coincides with the positive direction of the X-axis. In addition, let the length of the vector connecting the lattice point O and the center of gravity G be r(x, y). In one example, r(x, y) is constant in the phase modulation layer 15 as a whole regardless of x and y.

[0069] like Figure 3 As shown, the direction of the vector connecting the lattice point O and the center of gravity G, that is, the rotation angle φ around the lattice point O of the center of gravity G of the different refractive index region 15b, is set individually for each lattice point O according to the phase pattern corresponding to the desired light image. The phase pattern, that is, the rotation angle distribution φ(x, y), has a specific value for each position determined by the values ​​of x and y, but is not necessarily limited to being represented by a specific function. The rotation angle distribution φ(x, y) is determined by extracting the distribution of the phase distribution from the complex amplitude distribution obtained by Fourier transforming the desired light image. When obtaining the complex amplitude distribution based on the desired light image, the reproducibility of the beam pattern can be improved by applying an iterative algorithm such as the Gerchberg-Saxton (GS) method generally used in computer-generated holography.

[0070] Figure 5 FIG. 1 is a top view showing an example of applying a roughly periodic structure of a refractive index in a specific region of a phase modulation layer. Figure 5 In the example shown, a substantially periodic structure (eg, Figure 3 Structure shown). On the other hand, in the outer region ROUT surrounding the inner region RIN, a perfect circular region of different refractive index with the same center of gravity is arranged at the lattice point position of the square lattice. The filling factor FF in the outer region ROUT is set to, for example, 12%. Inside the inner region RIN and in the outer region ROUT, the lattice spacing of the square lattice is assumed to be the same (= a). In the case of this structure, light is also distributed in the outer region ROUT, so the generation of high-frequency noise (so-called window function noise) caused by the sudden change in light intensity on the peripheral part of the inner region RIN can be suppressed. In addition, light leakage in the in-plane direction can be suppressed, and a reduction in the threshold current can be expected.

[0071] Figure 6It is a diagram showing the relationship between the optical image obtained by imaging the output beam pattern of S-iPMSEL1 and the rotational angle distribution φ(x, y) on the phase modulation layer 15. The center Q of the output beam pattern is not limited to being located on the axis perpendicular to the main surface 10a of the semiconductor substrate 10, and can also be arranged on the perpendicular axis. In Figure 6 For ease of explanation, it is assumed that the center Q is located on the axis perpendicular to the main surface 10a. Figure 6 Four quadrants with the center Q as the origin are shown in Figure 6 In the example of , the character "A" appears in the third quadrant, and a symbol obtained by rotating the character "A" by 180 degrees appears in the first quadrant. When the output beam pattern is a rotationally symmetric optical image (such as a cross, a circle, a double circle, etc.), they are overlapped and observed as one optical image. As shown in Figure 4 When the centroid G of the different refractive index regions 15b of S-iPMSEL1 is shifted in the circumferential direction around the lattice point O, as shown in Figure 6 shown, there is no intensity difference between the output beam pattern in the first quadrant and the output beam pattern in the third quadrant. However, as shown in Figure 14 shown, when the centroid G of the different refractive index regions 15b of S-iPMSEL1 is shifted on the straight line passing through the lattice point O, an intensity difference can be created between the output beam pattern in the first quadrant and the output beam pattern in the third quadrant.

[0072] The optical image of the output beam pattern of S-iPMSEL1 includes at least one of speckles, dots, straight lines, crosses, line drawings, lattice patterns, photographs, striped patterns, CG (computer graphics), and characters. In order to obtain a desired optical image, the rotational angle distribution φ(x, y) of the different refractive index regions 15b on the phase modulation layer 15 is determined through the following steps.

[0073] As a first prerequisite, in the XYZ orthogonal coordinate system defined by the Z axis coinciding with the normal direction and the X-Y plane coinciding with one surface of the phase modulation layer 15 including a plurality of different refractive index regions 15b, a hypothetical square lattice composed of M1 (an integer of 1 or more) × N1 (an integer of 1 or more) units having a square shape is set on the X-Y plane.

[0074] As a second prerequisite, as shown in Figure 7 shown, it is assumed that the coordinates (ξ, η, ζ) in the XYZ orthogonal coordinate system satisfy the relationships shown in the following equations (1) to (3) with respect to the spherical coordinates (r, θrot, θtilt) defined by the length r of the radius vector, the tilt angle θtilt from the Z axis, and the rotation angle θrot from a specific X axis on the XY plane. Figure 7This is a diagram for explaining the coordinate transformation from spherical coordinates (r, θrot, θtilt) to coordinates (ξ, η, ζ) in the XYZ orthogonal coordinate system, and represents a designed light image in real space, i.e., on a specified plane set in the XYZ orthogonal coordinate system, through the coordinates (ξ, η, ζ).

[0075] Let the beam pattern corresponding to the light image output from S-iPMSEL1 be a set of bright spots directed towards the direction specified by the angles θtilt and θrot. At this time, let the angles θtilt and θrot be angles converted into the normalized wave numbers specified by the following formula (4), i.e., the coordinate value kx on the Kx axis corresponding to the X axis, and the normalized wave numbers specified by the following formula (5), i.e., the coordinate value ky on the Ky axis corresponding to the Y axis and orthogonal to the Kx axis. The normalized wave number refers to the wave number obtained by normalizing the wave number 2π / a corresponding to the lattice spacing of the imaginary square lattice to 1.0. At this time, within the wave number space defined by the Kx axis and the Ky axis, specific wave number ranges including the beam pattern corresponding to the light image are each composed of square-shaped M2 (an integer greater than or equal to 1) × N2 (an integer greater than or equal to 1) image regions FR. The integer M2 does not need to be the same as the integer M1. Similarly, the integer N2 does not need to be the same as the integer N1. Formulas (4) and (5) are disclosed in, for example, Y. Kurosaka et al., ″Effects of non-lasing band in two-dimensional photonic-crystal lasers clarified using omnidirectional bandstructure,″ Opt. Express 20, 21773 - 21783 (2012).

[0076] [Equation 1]

[0077] ξ = r sinθ tilt cosθ rot …(1)

[0078] [Equation 2]

[0079] η = r sinθ tilt sinθ rot …(2)

[0080] [Equation 3]

[0081] ζ = r cosθ tilt …(3)

[0082] [Equation 4]

[0083]

[0084] [Equation 5]

[0085]

[0086] a: Lattice constant of the imaginary square lattice

[0087] λ: Oscillation wavelength of S-iPMSEL1

[0088] As a third prerequisite, in the wavenumber space, with j as the imaginary unit, the two-dimensional inverse discrete Fourier transform of each of the image regions FR(kx, ky) that specify the coordinate component kx (an integer from 0 to M2 - 1) in the Kx-axis direction and the coordinate component ky (an integer from 0 to N2 - 1) in the Ky-axis direction is given by the complex amplitude F(x, y) of the unit constituent region R(x, y) on the X-Y plane that specifies the coordinate component x (an integer from 0 to M1 - 1) in the X-axis direction and the coordinate component y (an integer from 0 to N1 - 1) in the Y-axis direction through the following formula (6). Let the amplitude term be A(x, y) and the phase term be P(x, y). At this time, the complex amplitude F(x, y) is defined by the following formula (7). As a fourth prerequisite, the unit constituent region R(x, y) is defined by the s-axis and the t-axis that are respectively parallel to the X-axis and the Y-axis and orthogonal at the lattice point O(x, y) that is the center of the unit constituent region R(x, y).

[0089] [Equation 6]

[0090]

[0091] [Equation 7]

[0092] F(x, y) = A(x, y) × exp[jP(x, y)]…(7)

[0093] Under the above first to fourth prerequisites, the phase modulation layer 15 is configured to satisfy the following fifth and sixth conditions. That is, within the unit constituent region R(x, y), it is arranged in a state where the centroid G is away from the lattice point O(x, y), thereby satisfying the fifth condition. In a state where the line segment length r2(x, y) from the lattice point O(x, y) to the corresponding centroid G is set to a common value for each of the M1 × N1 unit constituent regions R, the corresponding different refractive index regions 15b are arranged within the unit constituent region R(x, y) so that the angle φ(x, y) formed by the line segment connecting the lattice point O(x, y) and the corresponding centroid G and the s-axis satisfies the following relationship, thereby satisfying the sixth condition:

[0094] φ(x, y) = C × P(x, y) + B

[0095] C: Proportional constant and for example 180° / π

[0096] B: Arbitrary constant and for example 0

[0097] Next, the oscillation at point M of S-iPMSEL1 will be described. To perform the oscillation at point M of S-iPMSEL1, it can be assumed that the lattice pitch a of the imaginary square lattice, the emission wavelength λ of the active layer 12, and the equivalent refractive index n of the mode satisfy the condition of λ = (√2)n × a. Figure 8 It is a top view of the reciprocal lattice space of the phase modulation layer of the S-iPMSEL for the oscillation at point M. The point P in the figure represents the reciprocal lattice point. The arrow B1 in the figure represents the basic reciprocal lattice vector, and the arrows K1, K2, K3, and K4 represent the four in-plane wave number vectors. The in-plane wave number vectors K1 to K4 each have a wave number spread SP based on the rotation angle distribution φ(x, y).

[0098] The shape and size of the wave number spread SP are the same as those in the case of the Γ-point oscillation described above. In S-iPMSEL1 with the oscillation at point M, the magnitudes of the in-plane wave number vectors K1 to K4 (i.e., the magnitudes of the standing waves in the in-plane direction) are smaller than the magnitude of the basic reciprocal lattice vector B1. Therefore, the sum of the vectors of the in-plane wave number vectors K1 to K4 and the basic reciprocal lattice vector B1 is not 0, and the wave number in the in-plane direction cannot be 0 by diffraction. Thus, the 0th-order light in the direction perpendicular to the plane (Z-axis direction), the 1st-order light, and the -1st-order light in the direction inclined with respect to the Z-axis direction are not output.

[0099] In the present embodiment, the following measures are taken for the phase modulation layer 15 in S-iPMSEL1 with the oscillation at point M, whereby it is possible to output a part of the 1st-order light and the -1st-order light without outputting the 0th-order light. Specifically, as Figure 9 shown, by adding a certain diffraction vector V having a certain magnitude and direction to the in-plane wave number vectors K1 to K4, it is possible to make the magnitude of at least one of the in-plane wave number vectors K1 to K4 (the in-plane wave number vector K3 in the figure) smaller than 2π / λ. In other words, at least one of the in-plane wave number vectors K1 to K4 (the in-plane wave number vector K3) after adding the diffraction vector V converges within a circular region (light ray) LL with a radius of 2π / λ.

[0100] In Figure 9 , the in-plane wave number vectors K1 to K4 represented by the dashed lines indicate before the addition operation of the diffraction vector V, and the in-plane wave number vectors K1 to K4 represented by the solid lines indicate after the addition operation of the diffraction vector V. The light ray LL corresponds to the total reflection condition, and the wave number vector with a magnitude converging within the light ray LL has a component in the direction perpendicular to the plane (Z-axis direction). In one example, the direction of the diffraction vector V is along the Γ-M1 axis or the Γ-M2 axis. The magnitude of the diffraction vector V is in the range of 2π / (√2)a - 2π / λ to 2π / (√2)a + 2π / λ. As an example, the magnitude of the diffraction vector V is 2π / (√2)a.

[0101] Next, the discussion is about the magnitude and direction of the diffraction vector V that converges at least one of the in-plane wave number vectors K1 to K4 within the light ray LL. The following mathematical expressions (8) to (11) represent the in-plane wave number vectors K1 to K4 before adding the diffraction vector V.

[0102] [Equation 8]

[0103]

[0104] [Equation 9]

[0105]

[0106] [Equation 10]

[0107]

[0108] [Equation 11]

[0109]

[0110] The diffusion of the wave number vector, Δkx and Δky, respectively satisfy the following mathematical expressions (12) and (13). The maximum values of the diffusion of the in-plane wave number vector in the x-axis direction, Δkxmax, and in the y-axis direction, Δkymax, are specified by the angular diffusion of the designed optical image.

[0111] [Equation 12]

[0112] -Δkx max ≤Δkx≤Δkx max …(12)

[0113] [Equation 13]

[0114] -Δky max ≤Δky≤Δky max …(13)

[0115] When the diffraction vector V is expressed as the following mathematical expression (14), the in-plane wave number vectors K1 to K4 after adding the diffraction vector V become the following mathematical expressions (15) to (18).

[0116] [Equation 14]

[0117] V = (Vx, Vy)…(14)

[0118] [Equation 15]

[0119]

[0120] [Equation 16]

[0121]

[0122] [Number 17]

[0123]

[0124] [Number 18]

[0125]

[0126] If any one of the wave number vectors K1 to K4 in the mathematical expressions (15) to (18) is considered to converge within the ray LL, the relationship of the following mathematical expression (19) holds.

[0127] [Number 19]

[0128]

[0129] That is, by adding the diffraction vector V that satisfies the mathematical expression (19), any one of the wave number vectors K1 to K4 converges within the ray LL, and a part of the first-order light and the -first-order light is output.

[0130] The reason for setting the size (radius) of the ray LL to 2π / λ is as follows. Figure 10 This is a diagram for schematically explaining the peripheral structure of the ray LL. The boundary between the device and air observed from the direction perpendicular to the Z-axis direction is shown in this diagram. The magnitude of the wave number vector of light in vacuum is 2π / λ, but when light propagates in the device medium as Figure 10 such, the magnitude of the wave number vector Ka in the medium with a refractive index n is 2πn / λ. At this time, in order for light to propagate at the boundary between the device and air, it is necessary to make the wave number component parallel to the boundary continuous (wave number conservation law).

[0131] In Figure 10 , when the wave number vector Ka forms an angle θ with the Z-axis, the length of the wave number vector projected onto the plane (i.e., the in-plane wave number vector) Kb is (2πn / λ)sinθ. On the other hand, generally, according to the relationship of the refractive index n>1 of the medium, in the angle where the in-plane wave number vector Kb in the medium is greater than 2π / λ, the wave number conservation law does not hold. At this time, total internal reflection of light occurs and it cannot be taken out to the air side. The magnitude of the wave number vector corresponding to this total internal reflection condition is the size of the ray LL, that is, 2π / λ.

[0132] As an example of a specific method of adding the in-plane wave number vectors K1 to K4 and the diffraction vector V, consider a method of overlapping the rotation angle distribution φ2(x, y) (second phase distribution) independent of the optical image and the phase distribution corresponding to the optical image, i.e., the rotation angle distribution φ1(x, y) (first phase distribution). In this case, the rotation angle distribution φ(x, y) of the phase modulation layer 15 is expressed as φ(x, y) = φ1(x, y) + φ2(x, y). As described above, φ1(x, y) corresponds to the phase of the complex amplitude when performing a Fourier transform on the optical image. φ2(x, y) is the rotation angle distribution for adding the diffraction vector V that satisfies the above equation (19).

[0133] Figure 11 FIG. is a diagram conceptually showing an example of the rotation angle distribution φ2(x, y). In the example of this figure, the first phase value φA and the second phase value φB different from the first phase value φA are arranged in a checkerboard pattern. In one example, the phase value φA is 0 (rad), and the phase value φB is π (rad). In this case, the first phase value φA and the second phase value φB change for each π. By this arrangement of phase values, it is possible to preferably achieve the diffraction vector V along the Γ-M1 axis or the Γ-M2 axis. In the case of being arranged in a checkerboard pattern, V = (±π / a, ±π / a), and the diffraction vector V and Figure 8 the wave number vectors K1 to K4 exactly cancel each other. In addition, the angular distribution θ2(x, y) of the diffraction vector V is represented by the inner product of the diffraction vector V (Vx, Vy) and the position vector r(x, y). That is, the angular distribution θ2(x, y) of the diffraction vector V is represented by θ2(x, y) = V·r = Vxx + Vyy.

[0134] In the above-described embodiment, when the wave number diffusion based on the angular diffusion of the optical image is included in a circle with a radius Δk centered at a certain point in the wave number space, it can also be simply considered that: by adding the diffraction vector V to the in-plane wave number vectors K1 to K4 in four directions, the magnitude of at least one of the in-plane wave number vectors K1 to K4 in four directions becomes less than 2π / λ (light ray LL). It can also be considered that: by removing the wave number diffusion Δk from the in-plane wave number vectors K1 to K4 in four directions and then adding the diffraction vector V, the magnitude of at least one of the in-plane wave number vectors K1 to K4 in four directions becomes less than the value obtained by subtracting the wave number diffusion Δk from 2π / λ, i.e., {(2π / λ) - Δk}.

[0135] Figure 12 FIG. is a diagram conceptually showing the above state. As shown in this figure, if the in-plane wave number vectors K1 to K4 from which the wave number diffusion Δk has been removed are added with the diffraction vector V, the magnitude of at least one of the in-plane wave number vectors K1 to K4 becomes less than {(2π / λ) - Δk}. In Figure 12 FIG., the region LL2 is a circular region with a radius of {(2π / λ) - Δk}. InFigure 12 Among them, the in-plane wave number vectors K1 to K4 represented by the dashed line indicate before the addition operation of the diffraction vector V, and the in-plane wave number vectors K1 to K4 represented by the solid line indicate after the addition operation of the diffraction vector V. The region LL2 corresponds to the total reflection condition considering the wave number spread Δk, and the wave number vectors converging to the size within the region LL2 also propagate in the direction perpendicular to the plane (Z-axis direction).

[0136] In this method, the magnitude and direction of the diffraction vector V for converging at least one of the in-plane wave number vectors K1 to K4 into the region LL2 are described. The following mathematical expressions (20) to (23) represent the in-plane wave number vectors K1 to K4 before adding the diffraction vector V.

[0137] [Equation 20]

[0138]

[0139] [Equation 21]

[0140]

[0141] [Equation 22]

[0142]

[0143] [Equation 23]

[0144]

[0145] Here, when the diffraction vector V is expressed as the above mathematical expression (14), the in-plane wave number vectors K1 to K4 after adding the diffraction vector V are the following mathematical expressions (24) to (27).

[0146] [Equation 24]

[0147]

[0148] [Equation 25]

[0149]

[0150] [Equation 26]

[0151]

[0152] [Equation 27]

[0153]

[0154] In Eqs. (24) to (27), if any one of the in-plane wave number vectors K1 to K4 converges within region LL2, the relationship of the following Eq. (28) holds. That is, by adding a diffraction vector V that satisfies Eq. (28), any one of the in-plane wave number vectors K1 to K4 from which the wave number spread Δk has been removed converges within region LL2. Even in such a case, it is possible to output the first-order light and a part of the -first-order light without outputting the zero-order light.

[0155] [Equation 28]

[0156]

[0157] Figure 13 is a top view of the phase modulation layer of the modified example. Figure 14 is a diagram showing the positional relationship of the different refractive index regions on the phase modulation layer of the modified example. As Figure 13 and Figure 14 shown, the center of gravity G of each different refractive index region 15b of the phase modulation layer 15 of the modified example is arranged on the straight line D. The straight line D is a straight line that passes through the lattice points O corresponding to each unit constituent region R and is inclined with respect to each side of the square lattice. That is, the straight line D is a straight line that is inclined with respect to both the X-axis and the Y-axis. The inclination angle of the straight line D with respect to one side (X-axis) of the square lattice is θ.

[0158] The inclination angle θ is constant within the phase modulation layer 15B. The inclination angle θ satisfies 0° < θ < 90°, and in one example, θ = 45°. Alternatively, the inclination angle θ satisfies 180° < θ < 270°, and in one example, θ = 225°. When the inclination angle θ satisfies 0° < θ < 90° or 180° < θ < 270°, the straight line D extends from the first quadrant to the third quadrant of the coordinate plane defined by the X-axis and the Y-axis. The inclination angle θ satisfies 90° < θ < 180°, and in one example, θ = 135°. Alternatively, the inclination angle θ satisfies 270° < θ < 360°, and in one example, θ = 315°. When the inclination angle θ satisfies 90° < θ < 180° or 270° < θ < 360°, the straight line D extends from the second quadrant to the fourth quadrant of the coordinate plane defined by the X-axis and the Y-axis. In this way, the inclination angle θ becomes an angle other than 0°, 90°, 180°, and 270°.

[0159] Here, let the distance between the lattice point O and the center of gravity G be r(x, y). x is the position of the x-th lattice point on the X-axis, and y is the position of the y-th lattice point on the Y-axis. When the distance r(x, y) is positive, the center of gravity G is located in the first quadrant (or the second quadrant). When the distance r(x, y) is negative, the center of gravity G is located in the third quadrant (or the fourth quadrant). When the distance r(x, y) is 0, the lattice point O and the center of gravity G coincide with each other. The inclination angle is preferably 45°, 135°, 225°, or 275°. Among these inclination angles, only two of the four wave number vectors (for example, the in-plane wave number vectors (±π / a, ±π / a)) that form the standing wave at point M are phase-modulated, and the remaining two are not phase-modulated. Therefore, a stable standing wave can be formed.

[0160] According to the phase pattern corresponding to the desired optical image, the distance r(x, y) between the center of gravity G of each different refractive index region and the lattice point O corresponding to each unit constituent region R is set individually for each different refractive index region 15b. The phase pattern, that is, the distribution of the distance r(x, y), has a specific value for each position determined by the values of x and y, but does not necessarily have to be represented by a specific function. The distribution of the distance r(x, y) is determined based on the distribution of the phase distribution extracted from the complex amplitude distribution obtained by performing an inverse Fourier transform on the desired optical image.

[0161] As Figure 14 shown, when the phase P(x, y) at a certain coordinate (x, y) is P 0 , the distance r(x, y) is set to 0. When the phase P(x, y) is π + P 0 , the distance r(x, y) is set to the maximum value R 0 . When the phase P(x, y) is -π + P 0 , the distance r(x, y) is set to the minimum value -R 0 . For intermediate phases P(x, y), the distance r(x, y) is taken such that r(x, y) = {P(x, y) - P 0} × R 0 / π. The initial phase P 0 can be set arbitrarily.

[0162] If the lattice spacing of the imaginary square lattice is set to a, the maximum value R 0 of r(x, y) is within the range of, for example, the following formula (29). When obtaining the complex amplitude distribution according to the desired optical image, by applying an iterative algorithm such as the Gerchberg-Saxton (GS) method commonly used in computer-generated hologram generation, the reproducibility of the beam pattern can be improved.

[0163] [Equation 29]

[0164]

[0165] In this method, by determining the distribution of the distance r(x, y) of the different refractive index regions 15b of the phase modulation layer 15, a desired optical image can be obtained. Under the same first to fourth preconditions as in the above-described embodiment, the phase modulation layer 15 is configured to satisfy the following conditions. That is, the corresponding different refractive index regions 15b are arranged within the unit constituent region R(x, y) so that the distance r(x, y) from the lattice point O(x, y) to the centroid G of the corresponding different refractive index region 15b satisfies the following relationship:

[0166] r(x, y) = C × (P(x, y) - P 0 )

[0167] C: proportional constant and for example R 0 / π

[0168] P 0 : arbitrary constant and for example 0

[0169] When the phase P(x, y) at a certain coordinate (x, y) is P 0 , the distance r(x, y) is set to 0. When the phase P(x, y) is π + P 0 , the distance r(x, y) is set to the maximum value R 0 . When the phase P(x, y) is -π + P 0 , the distance r(x, y) is set to the minimum value -R 0 . When a desired optical image is to be obtained, the optical image is subjected to an inverse Fourier transform, and the distribution of the distance r(x, y) corresponding to the phase P(x, y) of the complex amplitude is given to the plurality of different refractive index regions 15b. The phase P(x, y) and the distance r(x, y) may also be proportional to each other.

[0170] In this method, similar to the above-described embodiment, the lattice pitch a of the imaginary square lattice and the emission wavelength λ of the active layer 12 satisfy the condition of M point oscillation. When considering the reciprocal lattice space on the phase modulation layer 15, the magnitude of at least one of the in-plane wave number vectors in the four directions including the wave number diffusion based on the distribution of the distance r(x, y) can be less than 2π / λ (light ray).

[0171] In this method, by performing the following process on the phase modulation layer 15 in the S-iPMSEL1 oscillating at the M point, the 0th order light is not output into the light ray but the 1st order light and a part of the -1st order light are output. Specifically, as Figure 9As shown, by adding a diffraction vector V having a certain magnitude and direction to the in-plane wave number vectors K1 to K4, the magnitude of at least one of the in-plane wave number vectors K1 to K4 can be made less than 2π / λ. That is, at least one of the in-plane wave number vectors K1 to K4 after adding the diffraction vector V converges within a circular region (light beam) LL with a radius of 2π / λ. By adding the diffraction vector V that satisfies the above equation (19), any one of the in-plane wave number vectors K1 to K4 converges within the light beam LL, and a part of the first-order light and the -first-order light is output.

[0172] As Figure 12 shown, by removing the wave number spread Δk from the in-plane wave number vectors K1 to K4 in four directions (i.e., the in-plane wave number vectors in four directions in the square lattice PCSEL that oscillates at point M) and then adding the diffraction vector V, the magnitude of at least one of the in-plane wave number vectors K1 to K4 in four directions can be made less than the value obtained by subtracting the wave number spread Δk from 2π / λ, i.e., {(2π / λ) - Δk}. That is, by adding the diffraction vector V that satisfies the above equation (28), any one of the in-plane wave number vectors K1 to K4 converges within the region LL2, and a part of the first-order light and the -first-order light is output.

[0173] As an example of a specific method of adding the diffraction vector V to the in-plane wave number vectors K1 to K4, a method of overlapping the distance distribution r2(x, y) (second phase distribution) that is independent of the optical image and the phase distribution corresponding to the optical image, i.e., the distance distribution r1(x, y) (first phase distribution), is considered. In this case, the distance distribution r(x, y) of the phase modulation layer 15 is expressed as:

[0174] r(x, y) = r1(x, y) + r2(x, y).

[0175] As described above, r1(x, y) corresponds to the phase of the complex amplitude when performing a Fourier transform on the optical image. r2(x, y) is the distance distribution for adding the diffraction vector V that satisfies the above equation (19) or equation (28). A specific example of the distance distribution r2(x, y) is the same as Figure 11 the same.

[0176] [First Embodiment of Three-Dimensional Measuring Device]

[0177] Figure 15This is a schematic diagram showing the structure of the three-dimensional measurement device 101A according to the first embodiment. As shown in this figure, the three-dimensional measurement device 101A includes a single light source unit 102, a plurality of (a pair of) imaging units 103, and a measurement unit 104. The light source unit 102 is composed of the S-iPMSEL1 that oscillates at the above-mentioned M points. The measurement light 105 emitted from the light source unit 102 is irradiated onto a certain area on the surface of the object SA to be measured placed on the workbench 106. The workbench 106 can also be a scanning workbench that can be scanned in two-dimensional or three-dimensional directions. When the irradiation range of the measurement light 105 is sufficiently large relative to the measurement range of the object SA to be measured, the configuration of the workbench 106 can also be omitted.

[0178] In the present embodiment, the specified pattern of the measurement light 105 is a periodic pattern W1 composed of any one of a dot pattern, a bar pattern, and a lattice pattern. In Figure 16 the example, the periodic pattern W1 of the measurement light 105 is a periodic dot pattern represented by an image area of 100×100 pixels. In this dot pattern, the dots are arranged in a matrix, and the dot period is 5 pixel periods both horizontally and vertically. Figure 17 This is a diagram showing an example of the far-field image of the periodic pattern. Figure 17 (a) is the far-field image of 40×40 dots, Figure 17 (b) is the far-field image of 60×60 dots, Figure 17 (c) is the far-field image of 80×80 dots, Figure 17 (d) is the far-field image of 120×120 dots. The driving conditions of the light source unit 102 are a current of 0.5 A, a pulse width of 50 ns, a pulse interval of 5 μs, and a temperature of 25 °C. The center of the figure is the center in the direction perpendicular to the plane of the measurement light 105, and the calibration lines in the figure correspond to 15°. The far-field images shown in these figures are designed such that the dots are arranged in a matrix on a flat screen, and the distortion of the arrangement in the part far from the center is caused by the optical system of the measurement system.

[0179] The imaging unit 103 is composed of a device that is sensitive to the measurement light 105 emitted from the light source unit 102. As the imaging unit 103, for example, a CCD (Charge Coupled Device) camera, a CMOS (Complementary MOS) camera, or other two-dimensional image sensors can be used. The imaging unit 103 images the object SA in the state irradiated with the measurement light 105 and outputs an output signal representing the imaging result to the measurement unit 104.

[0180] The measuring unit 104 is composed of a computer system including, for example, a processor, a memory, etc. The measuring unit 104 performs various control functions through the processor. Examples of the computer system include personal computers, microcomputers, cloud servers, and smart devices (smart phones, tablet terminals, etc.). The measuring unit 104 may be composed of a PLC (programmable logic controller) or an integrated circuit such as an FPGA (field-programmable gate array).

[0181] The measuring unit 104 is connected to the imaging unit 103 so as to be communicable, and performs three-dimensional shape measurement of the object SA to be measured based on the output signal input from the imaging unit 103. In the present embodiment, the measuring unit 104 measures the three-dimensional shape of the object SA to be measured based on the active stereo method using the periodic pattern W1. Here, as an example, a three-dimensional shape measurement method based on the parallel equipotential stereo principle is shown. Let the parallax of a pair of imaging units 103, 103 be D, let the distance between the pair of imaging units 103, 103 be b, let the focal length of the pair of imaging units 103, 103 be f, let the distance from the pair of imaging units 103, 103 to the object SA to be measured be Z, in this case, the parallax D is assigned D = (f / Z) b. The distance b between the imaging units 103, 103 and the focal length of the imaging units 103, 103 are both inherent values, so by obtaining the parallax D, the distance Z from the object SA to be measured can be obtained.

[0182] In this embodiment, the measuring light 105 having the periodic pattern W1 is irradiated onto the object to be measured SA. At this time, the measuring unit 104 can identify the same point of the periodic pattern W1 photographed by the imaging units 103, 103. In addition, three-dimensional measurement using images with little texture, which is a technical problem in the passive stereo method, and three-dimensional measurement in dark areas can be performed. By using the periodic pattern W1 represented by periodic dots, the deviation of the pattern density of the measuring light 105 can be suppressed, and the unevenness of the measurement accuracy caused by the illumination position of the measuring light 105 can be suppressed.

[0183] In this embodiment, for example, Figure 18 The random dot pattern W2 shown replaces the periodic pattern W1. Figure 16 The dot pattern shown is a pattern in which each dot is randomly displaced two-dimensionally from the position of the grid point within the range of the basic period area (a rectangular area surrounded by a line segment perpendicular to the midpoint between adjacent grid points). As an example, a random number φ(ix, iy) can be assigned to each dot located at the grid point, and based on the random number φ, each dot is displaced from the position of the grid point.

[0184] In this case, the random dot pattern W2 has a pseudo-period. Therefore, by suppressing the deviation of the pattern density of the measurement light 105, the unevenness of the measurement accuracy caused by the illumination position of the measurement light 105 can be suppressed. In addition, by using the random dot pattern W2 instead of the periodic dot pattern, misidentification when imaging the same point of the dot pattern by different imaging units 103 can be suppressed. Therefore, the measurement accuracy of the parallax D can be improved, and the accuracy of three-dimensional shape measurement can be improved.

[0185] In the present embodiment, it is also possible to use Figure 19 the pattern W3 with a uniform density shown in FIG. to replace the periodic pattern W1. Since the emitted light from the S-iPMSEL1 is a laser, speckles may appear in the scattered light. In addition, in the phase calculation, accidental speckle-like noise may sometimes be mixed in. Therefore, even when using the pattern W3 with a uniform density, a random dot pattern is formed in the pattern of the measurement light 105. By using this random dot pattern, misidentification when imaging the same point of the dot pattern by different imaging units 103 can be suppressed.

[0186] Figure 20 FIG. is an example of the FFP (Far Field Pattern) of the pattern W3 with a uniform density. In the example of this figure, the pulse width of the measurement light 105 is set to 50 ns, the repetition interval is set to 5 μs, and the FFP is observed at room temperature. In addition, tone correction with a brightness of +40% and a contrast of -40% is performed. In this figure, it can be confirmed that even when using the pattern W3 with a uniform density, a random dot pattern is formed in the pattern of the measurement light 105.

[0187] In Figure 15 the example of FIG., the three-dimensional measurement device 101A includes a single light source unit 102, but the three-dimensional measurement device 101A may also include a plurality of light source units 102. In this case, by irradiating the measurement light 105 from each light source unit 102 to different regions of the object to be measured SA, the measurement region can be expanded without scanning the workbench 106. In the case of adopting this structure, the configuration of the workbench 106 can be omitted.

[0188] [Second Embodiment of Three-Dimensional Measurement Device]

[0189] Figure 21It is a schematic diagram showing the structure of the three-dimensional measurement device according to the second embodiment. As shown in this figure, the three-dimensional measurement device 101B according to the second embodiment includes a plurality of light source units 102, a single imaging unit 103, and a measurement unit 104. The structures of the imaging unit 103, the light source unit 102, and the measurement unit 104 are the same as those in the first embodiment. In this embodiment, the specified pattern of the measurement light 105 is a Gray code pattern, and the measurement unit 104 measures the three-dimensional shape of the object to be measured SA based on the triangulation method using the Gray code pattern.

[0190] Figure 22 It is a diagram showing an example of the Gray code pattern. In the example of this figure, the pixels of the imaging unit 103 are Nx×Ny, and the pixels in the X direction are shown. If the pixel position n (n is an integer from 0 to Nx−1) in the X direction is a binary number of Mx bits, the Gray code pattern W4 is composed of the binary representation of the object number and the exclusive OR representation of the number obtained by shifting the binary representation of the object number one bit to the right and prepending 0. That is, if the object number is n, the Gray code pattern W4 is expressed by the logical expression of n ^ (n >> 1). In Figure 22 the example, the Gray code patterns W4a to W4d in the case of 4 bits (4 patterns) are shown. To generate the Gray code pattern W4, for example, OpenCV or the like can be used.

[0191] In Gray code, the Hamming distance between adjacent pixels is 1. The Hamming distance refers to the number of bits with different values at the corresponding positions when comparing two values with the same number of bits. Therefore, in Gray code with a Hamming distance of 1, even when a bit error occurs during the restoration of the bit stream, the error converges to 1. In a simple binary code, the error at the position where an error occurs in the upper bit increases, but in Gray code, a symbol with a large noise can be obtained.

[0192] When using Gray code, the number of configurations of the light source unit 102 is sufficient for the number of patterns corresponding to each bit of the binary number. That is, the Gray code patterns W4a to W4d are composed of a plurality of stripe-like patterns in which 0 and 1 of each pixel from the most significant bit to the least significant bit are set to be different from each other. In the light source unit 102, the patterns from the Gray code pattern W4a of the most significant bit to the Gray code pattern W4d of the least significant bit are sequentially switched, and at the same time, imaging is performed by the imaging unit 103. In this case, the value X can be obtained by Mx times of imaging. It can be known that the position of the Xth pixel is measured based on this value X. The same applies to the Y direction. By sequentially switching the Gray code patterns W4a to W4d and performing imaging by the imaging unit 103 at the same time, the value Y can be obtained by My times of imaging. It can be known that the position of the Yth pixel is measured based on this value Y.

[0193] To avoid misidentification caused by the color of the surface of the object to be measured SA, Figure 22The Gray code patterns W4a to W4d shown can also be used together with the black-and-white inverted Gray code pattern. In this case, the number of configurations of the light source unit 102 may be set to 2Mx + 2My.

[0194] In the present embodiment, for example, as Figure 23 shown, a sine-wave-shaped bar pattern W5 can also be used instead of the Gray code pattern W4. Figure 23 The sine-wave-shaped bar pattern W5 shown is a periodic bar pattern represented by an image area of 100 × 100 pixels. The period of the sine-wave-shaped bar pattern W5 is 20 pixel periods. The measurement unit 104 measures the three-dimensional shape of the object to be measured SA based on the phase shift method using the sine-wave-shaped bar pattern W5. In this method, for example, a plurality of sine-wave-shaped bar patterns W5 to which a phase shift (dislocation) equal to one period of the lattice pitch is applied are used. For the phase-shifted patterns, it is sufficient to prepare patterns in which the phase is shifted by 2π / N (N is an integer).

[0195] Here, the case of using four sine-wave-shaped bar patterns W5 having different phase shifts is illustrated. Let the light intensities of the measurement light 105 having the four sine-wave-shaped bar patterns W5 be I0 to I3, and let the pixels of the imaging unit 103 be (x, y). At this time, the light intensities I0 to I3 on the surface of the object to be measured SA are represented by the following equations (30) to (33). Ia(x, y) is the amplitude of the lattice pattern, Ib(x, y) is the background intensity, and θ(x, y) is the initial phase.

[0196] [Equation 30]

[0197] I0 = Ia(x, y)cos{θ(x, y)} + Ib(x, y)…(30)

[0198] [Equation 31]

[0199] I1 = Ia(x, y)cos{θ(x, y) + π / 2} + Ib(x, y)…(31)

[0200] [Equation 32]

[0201] I2 = Ia(x, y)cos{θ(x, y) + π} + Ib(x, y)…(32)

[0202] [Equation 33]

[0203] I3 = Ia(x, y)cos{θ(x, y) + 3π / 2} + Ib(x, y)…(33)

[0204] The initial phase θ can be obtained by tanθ = -(I3 - I1) / (I2 - I0). When the number of phase shifts of the sinusoidal bar pattern W5 is N, the initial phase θ can be obtained by the following formula (34).

[0205] [Equation 34]

[0206]

[0207] When using this phase shift method, by performing height conversion on the measured phase, the height of the object SA to be measured can be measured at intervals smaller than the pitch of the sinusoidal bar pattern W5. In the structure of the three-dimensional measurement device 101B, the light source units 102 can also be arranged along the direction parallel to the stripes in the sinusoidal bar pattern W5. In this case, the phase shift caused by the misalignment of the light source units 102 can be eliminated, and the offset of the initial phase of each of the plurality of sinusoidal bar patterns W5 can be eliminated.

[0208] In the present embodiment, the light source units 102 can also be arranged along two orthogonal axis directions. In this case, by switching the on / off of the measurement light 105 for each axis, the height curve of the object SA to be measured can be obtained through two axes. For example, as Figure 24 shown, a matrix pattern W6 that varies sinusoidally in two orthogonal axis directions can also be used instead of the sinusoidal bar pattern W5. When using such a matrix pattern W6, the height curve of the object SA to be measured can be measured simultaneously in the two-axis direction.

[0209] In the present embodiment, the plurality of light source units 102 can also output sinusoidal bar patterns W5 with different periods respectively. In the above phase shift method, the discontinuity at 2π in phase becomes a technical problem. In contrast, when using sinusoidal bar patterns W5 with different periods, for example, as Figure 25 shown, by selecting coordinates that are consistent at all frequencies, the discontinuity at 2π in phase can be improved, and high-precision three-dimensional measurement can be achieved with a small number of patterns. By improving the discontinuity at 2π in phase, the measurement range of three-dimensional shape measurement can be expanded, or high-precision measurement of the object SA with significant unevenness can be achieved.

[0210] In this embodiment, the measurement unit 104 may also measure the three-dimensional shape of the object SA to be measured based on the sampling Moiré method using the sine-wave-shaped bar pattern W5. In the sampling Moiré method, the lattice of the sine-wave-shaped bar pattern W5 projected onto the surface of the object SA to be measured is deformed according to the height of the object SA to be measured. Here, in the image captured by the imaging unit 103, the fringe interval of one sine-wave pattern at the height of the reference plane adjusted in advance corresponds to N pixels of the camera. Here, let the number of phase shifts N be 4. By irradiating one sine-wave pattern and sampling the pixels of the imaging unit 103 for every N = 4 pixels, as Figure 26 (a) shows, four patterns P1 to P4 captured for every 4 pixels (3 pixels between the captured pixels are sparsified) can be obtained. Between these patterns P1 to P4, the captured pixels are displaced by 1 pixel each, and the luminance values of the captured pixels are linearly complemented. Thus, as Figure 26 (b) shows, Moiré fringe patterns M1 to M4 with mutually displaced phases can be obtained. By using these Moiré fringe patterns M1 to M4 and applying the above-described phase-shift method, the height of the object SA to be measured can be measured at intervals smaller than the pitch of the sine-wave-shaped bar pattern W5. Compared with the above-described phase-shift method, according to this method, the number of sine-wave patterns to be irradiated can be reduced, and the light source unit 102 can be made compact.

[0211] In this embodiment, for example, as Figure 27 shown, an overlapping pattern W7 in which the sine-wave-shaped bar pattern W5 and the random dot pattern W2 are overlapped may be used instead of the sine-wave-shaped bar pattern W5. By using such an overlapping pattern W7, the height of the object SA to be measured can be measured at intervals smaller than the pitch of the sine-wave-shaped bar pattern W5. In addition, by combining the random dot pattern, the discontinuity at phase 2π can be improved, and high-precision three-dimensional measurement can be achieved with a small number of patterns. As Figure 28 shown, the overlapping pattern may also be an overlapping pattern W8 in which a matrix pattern W6 that changes in a sine-wave shape and the random dot pattern W2 are overlapped. In this case, in addition to the above effects, the height curve of the object SA to be measured can be measured simultaneously in the two-axis direction.

[0212] In this embodiment, both the sine-wave-shaped bar pattern W5 and the Gray code pattern W4 may be used. In this case, the measurement unit 104 measures the three-dimensional shape of the object SA to be measured based on the phase-shift method using the sine-wave-shaped bar pattern W5 and the triangulation method using the Gray code pattern W4. In this case, pixel-level measurement can be performed by the triangulation method using the Gray code pattern W4, and sub-pixel-level measurement can be performed by the phase-shift method using the sine-wave-shaped bar pattern W5. In addition, by using the Gray code, the discontinuity at phase 2π can be improved, and high-precision three-dimensional measurement can be achieved with a small number of patterns.

[0213] [Third Embodiment of 3D Measurement Device]

[0214] Figure 29 FIG. 6 is a schematic diagram showing the structure of the 3D measurement device according to the third embodiment. As shown in this figure, the 3D measurement device 101C according to the third embodiment includes a plurality of light source units 102, a plurality of (a pair of) imaging units 103, and a measurement unit 104. The structures of the imaging unit 103, the light source unit 102, and the measurement unit 104 are the same as those in the first embodiment. In this embodiment, the specified pattern of the measurement light 105 is a sine-wave-shaped bar pattern W5, and the measurement unit 104 measures the three-dimensional shape of the object to be measured SA based on the phase shift method and the active stereo method using the sine-wave-shaped bar pattern W5.

[0215] In this embodiment, by performing height conversion on the measured phase, it is possible to measure the height of the object to be measured SA at intervals smaller than the pitch of the sine-wave-shaped bar pattern W5. In addition, by combining the active stereo method using a plurality of imaging units 103, the discontinuity at 2π of the phase can be improved, and high-precision 3D measurement can be achieved with a small number of patterns. When using the active stereo method, it is also possible to use it while switching the above-mentioned dot pattern.

[0216] [Phase Shift of Sine-Wave-Shaped Bar Pattern Based on S-iPMSEL]

[0217] In the S-iPMSEL 1, in addition to the designed first-order light, the -1st order light symmetric with respect to the normal of the emission surface is also output (see Figure 6 ). Therefore, when performing phase shift of the sine-wave-shaped bar pattern W5, considering the sine wave with the overlapping of the ±1st order lights, at this time, the direction of the displacement of the fringe between the 1st order light and the -1st order light is reversed, and the pattern may deviate from the design. To simplify the explanation, considering the displacement of the fringe in the X-axis direction, at this time, the complex amplitude of the 1st order light is represented by the following equation (35). The complex amplitude of the -1st order light is the complex amplitude of the light emitted at a position symmetric to the 1st order light with respect to the surface normal, and is represented by the following equation (36). In the equations, k(=kx, ky, kz) is the wave number vector (magnitude 2π / λ), λ is the wavelength, ω is the frequency of each light, Δθ is the phase shift, a1 is the amplitude of the 1st order light (the component caused by the phase distribution of the actual hole configuration with respect to the ideal phase distribution), K is the wave number of the fringe of the sine wave (=2π / Λ (Λ is the period of the sine wave)), θ is the phase shift amount of the sine wave, and (x, y, z) is the coordinate of the projection light beam.

[0218] [Equation 35]

[0219] A 1 =a 1 cos(Kx + θ)exp{j(ωt - k xx - k y y - k z z)}…(35)

[0220] [Equation 36]

[0221] A -1 = a _1 cos(Kx + θ)exp{j(ωt + k x x + k y y - k z z)}…(36)

[0222] At this time, based on the amplitudes of the +1st order light and the -1st order light, the composite amplitude A can be obtained by the following equation (37).

[0223] [Equation 37]

[0224] A = cos(Kx + θ){a 1 exp[j{ωt - k z z - (k x x + k y y)}] + a -1 exp[j{ωt - k z z + (k x x + k y y)}]}…(37)

[0225] The actual light intensity is proportional to the square of the composite amplitude A. Therefore, it can be obtained by the following equation (38).

[0226] [Equation 38]

[0227]

[0228] The period of the fundamental light wave is sufficiently smaller than the period of the sine wave (λ << Λ). Therefore, the wave number k of the fundamental light wave is sufficiently larger than the wave number K of the sine wave fringes (k >> K). Therefore, it is also considered that in the above equation (38), the terms corresponding to the change in k can be averaged. In this case, the intensity I of the light after overlapping the ±1st order light can be approximated by the following equation (39).

[0229] [Equation 39]

[0230]

[0231] From these equations, it can be seen that when performing the phase shift of the sine-wave-shaped bar pattern W5, even if the ±1st-order lights overlap, the fringes are displaced while maintaining the sine-wave shape. It can also be seen that in the sine-wave pattern where the ±1st-order lights overlap, the interval of the fringes of the actually obtained light intensity (the square of the sum of the amplitudes of the ±1st-order lights) is halved with respect to the designed pattern (the amplitude of the 1st-order light), and the phase shift amount becomes twice that of one period. Therefore, for example, when achieving a phase shift of π / 2 under the finally obtained light intensity, the designed value of the phase shift amount of the 1st-order light amplitude can be set to π / 4. The same applies to the sine-wave-shaped matrix pattern W6 having a period in the two-axis direction.

[0232] As Figure 4 shown, when formed by shifting the centroid G of the different refractive index region 15b in the S-iPMSEL1 in the circumferential direction around the lattice point O, the amplitudes a of the 1st-order light and the -1st-order light become equal values. On the other hand, as Figure 14 shown, when formed by shifting the centroid G of the different refractive index region 15b in the S-iPMSEL1 through the lattice point O and shifting it on the straight line D inclined with respect to each side of the square lattice, the amplitudes a of the 1st-order light and the -1st-order light become different values. Even in either case, the sine-wave pattern with the overlap of the ±1st-order lights can be used.

[0233] In the case of a pattern where the 1st-order light and the -1st-order light are asymmetric, if the 1st-order light and the -1st-order light overlap, there is a problem that the designed pattern cannot be obtained. As an example of such a problem, it can be cited that the structure of each bright spot of the 1st-order light is asymmetrically diffused, and the designed pattern becomes blurred. In this case, it is only necessary to limit the emission region of the 1st-order light to a region with a solid angle of π. For example, when the emission region of the 1st-order light is limited to the first quadrant and the second quadrant, the emission region of the -1st-order light is the fourth quadrant and the third quadrant, so that the overlap of the 1st-order light and the -1st-order light can be avoided. Thereby, the diffusion of the bright spots caused by the overlap of the 1st-order light and the -1st-order light can be suppressed. When the lattice pattern is displaced by the phase shift method, the displacement direction of the -1st-order light is reversed with respect to the displacement direction of the 1st-order light. Therefore, it is preferable to reverse the phase obtained by the phase shift operation together with the emission regions of the 1st-order light and the -1st-order light. On the other hand, even when the above problem does not occur, an image with non-overlapping 1st-order light and -1st-order light and less noise can be obtained. In this case, the projection regions of the ±1st-order lights can be used separately without overlap.

[0234] [Configuration example of light source unit and imaging unit]

[0235] Figure 30 is a schematic perspective view showing a configuration example of the light source unit and the imaging unit. As Figure 30As shown, when constructing the three-dimensional measurement device 101, the light source unit 102 and the imaging unit 103 can be arranged on the surface of the three-dimensional object 111. The three-dimensional object 111 constitutes a part corresponding to the probe of the three-dimensional measurement devices 101A to 101C. The three-dimensional object 111 is formed in a cylindrical shape from, for example, metal or resin. The three-dimensional object 111 can have rigidity or flexibility. The three-dimensional object 111 can have an internal space.

[0236] The light source unit 102 and the imaging unit 103 are respectively arranged at regular intervals (here, a phase angle of 45°) in the circumferential direction on the circumferential surface 111a of the cylindrical three-dimensional object 111. In Figure 30 this example, a group of one imaging unit 103, a group of light source units 102, and a group of the other imaging unit 103 are arranged at regular intervals from the front end side to the base end side of the three-dimensional object 111. When observing the three-dimensional object 111 from the long side direction, one imaging unit 103, the light source unit 102, and the other imaging unit 103 are arranged in a line, and these groups constitute a measurement area for the object to be measured SA. When the three-dimensional object 111 has an internal space, wirings for the light source unit 102 and the imaging unit 103 and the like can be accommodated in this internal space. The arrangement intervals of the light source unit 102 and the imaging unit 103 can also be non-uniform intervals. When covering the measurement range for the object to be measured SA, a single light source unit 102 and a single imaging unit 103 can also be arranged on the three-dimensional object 111.

[0237] Figure 31 is a schematic perspective view showing another arrangement example of the light source unit and the imaging unit. In Figure 31 this example, the three-dimensional object 121 is formed in a spherical shape and is provided at the front end portion of, for example, a cylindrical support portion 122. The light source unit 102 and the imaging unit 103 are respectively arranged at regular intervals (here, a phase angle of 45°) in the longitude direction on the spherical surface 121a of the spherical three-dimensional object 121. A group of one imaging unit 103, a group of light source units 102, and a group of the other imaging unit 103 are arranged at regular intervals in the latitude direction of the three-dimensional object 121. One imaging unit 103, the light source unit 102, and the group of the other imaging unit 103 arranged in the longitude direction of the three-dimensional object 121 constitute a measurement area for the object to be measured SA. When the three-dimensional object 121 has an internal space, wirings for the light source unit 102 and the imaging unit 103 and the like can also be accommodated in this internal space. Similar to Figure 30 the case of, the arrangement intervals of the light source unit 102 and the imaging unit 103 can also be non-uniform intervals. When covering the measurement range for the object to be measured SA, a single light source unit 102 and a single imaging unit 103 can also be arranged on the three-dimensional object 121.

[0238] According to the above structure, the three-dimensional objects 111 and 121 equipped with the light source unit 102 and the imaging unit 103 can be configured as the probes of the three-dimensional measurement device 101. By using such three-dimensional objects 111 and 121, the groups of the light source unit 102 and the imaging unit 103 can be oriented in different directions from each other. Therefore, the three-dimensional shape measurement of the object to be measured SA can be performed with a large solid angle. In addition, it can be easily applied to uses such as oral examination, endoscopic examination, examination of narrow parts such as the inside of a tube or the gap between walls, examination from under the floor of furniture or devices, etc., or to construct a handheld three-dimensional measurement device.

[0239] Figure 23 A sine-wave-shaped bar pattern W5 is shown, but when forming this bar pattern, it is important to reduce the noise (brightness fluctuation) between adjacent patterns. It is also considered that the noise between adjacent patterns becomes the main cause of position fluctuation when applying the phase-shift method, for example, and affects the measurement accuracy. Therefore, when realizing the formation of a bar pattern with noise reduction between adjacent patterns considered, for example, as Figure 32 shown, a structure combining the S-iPMSEL1 that emits a one-dimensional multi-point pattern and the one-dimensional lens 51 can be adopted.

[0240] In Figure 32 's example, the one-dimensional lens 51 is a one-dimensional concave lens 52. The medium of the one-dimensional concave lens 52 is, for example, glass. One surface 52a of the one-dimensional concave lens 52 is a flat surface, and the other surface 52b is a concave surface. The one-dimensional concave lens 52 is arranged on the surface (laser emission surface) of the S-iPMSEL1 with one surface 52a facing the S-iPMSEL1. The one-dimensional concave lens 52 can also be coupled to the surface of the SiPMSEL1 and integrated with the S-iPMSEL1. The lens phase of the one-dimensional concave lens 52 is obtained by the following formula (40). In the following formula (40), φ is the lens phase, λ is the wavelength of the laser in the lens medium, and f is the focal length.

[0241] [Equation 40]

[0242]

[0243] In Figure 32 and Figure 33 (a)'s example, the laser La of the multi-point pattern from the S-iPMSEL1 is arranged at a prescribed interval in the X direction. In Figure 32 's example, the one-dimensional concave lens 52 is arranged such that the concave surface extends in the X-axis direction. The laser La of the multi-point pattern that has passed through the one-dimensional concave lens 52 does not change in the X-axis direction and only diffuses in the Y-axis direction. Therefore, by passing the laser La of the multi-point pattern through the one-dimensional concave lens 52, as Figure 33 (b) shows, a bar pattern W11 in which the linear lasers Lb diffused in the Y direction are arranged in the X-axis direction can be obtained.

[0244] In the case of making the bar pattern closer to a sine wave shape, for example, as Figure 34 (a) shows, the laser La forming the multi-point pattern has the brightness of each laser controlled to be in a sine wave shape with respect to the X-axis direction. By passing the laser La of such a multi-point pattern through the one-dimensional concave lens 52, in the Figure 34 (b) shown bar pattern W12, linear lasers Lb diffused in the Y direction are arranged along the X-axis direction, and the brightness of each laser Lb changes in a sine wave shape with respect to the X-axis direction.

[0245] In Figure 33 (a) and Figure 34 (a), the lasers La of the multi-point pattern are arranged in a straight line along the X-axis direction, but each laser La may not be arranged in a straight line, and may be periodically or randomly offset along the Y-axis direction. The one-dimensional lens 51 only needs to be a lens capable of diffusing the laser La of the multi-point pattern in one dimension, and is not limited to the one-dimensional concave lens 52, and may also be a Powell lens or a linear lens that functions as a line generator. The one-dimensional lens 51 may be, for example, a flat lens such as a Fresnel lens, a microlens, or a metalens.

[0246] In the case of using a metalens, for example, the resonant metalens structure 53A shown in Figure 35 (a) may be adopted, or the refractive index modulation type metalens structure 53B shown in Figure 35 (b) may be adopted. As Figure 35 (a) shows, in the case of adopting the resonant metalens structure 53A, the constituent material of the metalens structure 53A is a material having a refractive index higher than that of the layer serving as the substrate. For example, when the layer serving as the substrate (e.g., the antireflection film 19) is SiN, amorphous silicon can be used as the constituent material of the metalens structure 53A. The height and diameter of the unit lattice constituting the metalens structure 53A are set based on the lens phase obtained from the above formula (40).

[0247] As Figure 35 (b) shows, in the case of adopting the refractive index modulation type metalens structure 53B, the metalens structure 53B can be formed by etching the surface of the S-iPMSEL1. For example, on the surface of the S-iPMSEL1, by etching to form hole portions 54 in the middle from the outermost layer (e.g., the antireflection film 19) to its lower layer (e.g., the semiconductor substrate 10), the refractive index modulation type metalens structure 53B can be formed. The depth and diameter of each hole portion 54 constituting the metalens structure 53B are set based on the lens phase obtained from the above formula (40).

Claims

1. A three-dimensional measurement device, wherein, it includes: one or more light source units that irradiate a measurement object with measurement light having a specified pattern; one or more imaging units that image the measurement object irradiated with the measurement light; a measurement unit that measures the three-dimensional shape of the measurement object based on the imaging result of the imaging unit, the light source unit is composed of an S-iPMSEL oscillating at M points, the S-iPMSEL oscillating at M points includes an active layer and a phase modulation layer optically coupled to the active layer, the phase modulation layer includes a basic layer composed of a first refractive index medium and a plurality of different refractive index regions composed of a second refractive index medium having a refractive index different from that of the first refractive index medium, the plurality of different refractive index regions are arranged in a manner that satisfies the oscillation condition at M points at the reciprocal lattice points in the reciprocal lattice space corresponding to the wave number space of the phase modulation layer, when the emission wavelength of the active layer is set to λ, the magnitude of at least one of the in-plane wave number vectors formed in the reciprocal lattice space is less than 2π / λ.

2. The three-dimensional measurement device according to claim 1, wherein, it includes a single light source unit and a plurality of the imaging units, the specified pattern of the measurement light is a periodic pattern composed of any one of a dot pattern, a bar pattern, and a grid pattern, the measurement unit measures the three-dimensional shape of the measurement object based on the active stereo method using the periodic pattern.

3. The three-dimensional measurement device according to claim 1, wherein, it includes a single light source unit and a plurality of the imaging units, the specified pattern of the measurement light is a random dot pattern, the measurement unit measures the three-dimensional shape of the measurement object based on the active stereo method using the random dot pattern.

4. The three-dimensional measurement device according to claim 1, wherein, it includes a single light source unit and a plurality of the imaging units, the specified pattern of the measurement light is a pattern with uniform density, the measurement unit measures the three-dimensional shape of the measurement object based on the active stereo method using the pattern with uniform density.

5. The three-dimensional measurement device according to claim 1, wherein, it includes a plurality of the light source units and a single imaging unit, the specified pattern of the measurement light is a Gray code pattern, the measurement unit measures the three-dimensional shape of the measurement object based on the triangulation method using the Gray code pattern.

6. The three-dimensional measurement device according to claim 1, wherein, it includes a plurality of the light source units and a single imaging unit, the specified pattern of the measurement light is a sinusoidal bar pattern, the measurement unit measures the three-dimensional shape of the measurement object based on the phase shift method using the sinusoidal bar pattern.

7. The three-dimensional measurement device according to claim 6, wherein, the plurality of the light source units respectively output sinusoidal bar patterns with different periods.

8. The three-dimensional measurement device according to claim 1, wherein, it includes a plurality of the light source units and a single imaging unit, the specified pattern of the measurement light is a sinusoidal bar pattern, The measurement unit measures the three-dimensional shape of the object to be measured based on the sampling Moiré method using the sinusoidal bar pattern.

9. The three-dimensional measurement device according to claim 1, wherein, it includes a plurality of the light source units and the single imaging unit, the specified pattern of the measurement light is an overlapping pattern in which a sinusoidal bar pattern and a random dot pattern are overlapped, the measurement unit measures the three-dimensional shape of the object to be measured based on the phase shift method using the overlapping pattern.

10. The three-dimensional measurement device according to claim 1, wherein, it includes a plurality of the light source units and the single imaging unit, the specified pattern of the measurement light includes a sinusoidal bar pattern and a Gray code pattern, the measurement unit measures the three-dimensional shape of the object to be measured based on the phase shift method using the sinusoidal bar pattern and the triangulation method using the Gray code pattern.

11. The three-dimensional measurement device according to claim 1, wherein, it includes a plurality of the light source units and a plurality of the imaging units, the specified pattern of the measurement light is a sinusoidal bar pattern, the measurement unit measures the three-dimensional shape of the object to be measured based on the phase shift method using the sinusoidal bar pattern and the active stereo method.

12. The three-dimensional measurement device according to any one of claims 1 to 11, wherein, the light source unit and the imaging unit are arranged on the surface of the three-dimensional object.

Images