Semiconductor light-emitting device

Abstract

To provide a semiconductor light-emitting device that can reduce the amount of heat generated and downsize the device.SOLUTION: A semiconductor light-emitting device 1 includes a plurality of iPM lasers 2 having a first surface 2a and a second surface 2b opposite to the first surface 2a, and outputting light from the first surface 2a, and a drive circuit 3 that supplies a drive current to cause each of the plurality of iPM lasers 2 to emit light. The drive circuit 3 includes a common current source circuit for the plurality of iPM lasers 2, a plurality of switch sections that are provided corresponding to the plurality of iPM lasers 2 and switch the drive current on / off, and a switch operating unit that operates each of the plurality of switch units individually.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a semiconductor light emitting device. [Background technology]

[0002] In a semiconductor light-emitting device including multiple photonic crystal lasers, a driver circuit for driving each photonic crystal laser is known (see, for example, Non-Patent Document 1). Non-Patent Document 1 describes a driver circuit having multiple digital-to-analog converters, multiple operational amplifiers, and multiple transistors corresponding to each of the multiple photonic crystal lasers. The driver circuit described in Non-Patent Document 1 digitally converts a 12-bit digital control signal from a microcontroller to drive the transistor and control the current flowing through the laser.

[0003] Patent Document 1 discloses a shape measurement device that includes three or more light sources arranged in a row to project a grid pattern. Non-Patent Document 3 discloses a three-dimensional shape measurement method that uses structured illumination. Non-Patent Document 1 also discloses a phase shift method that uses a stripe pattern. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-242178 [Non-patent literature]

[0005] [Non-Patent Document 1] "Beam Shape Control Based on In-Plane Mutual Entrainment in Photonic Crystal Lasers," Menaka De Zoysa et al., Proceedings of the 81st Autumn Meeting of the Japan Society of Applied Physics, 10p-Z18-8, 2020 [Non-patent document 2] Y. Kurosaka et al., "Effects of non-lasing band in two-dimensional photonic-crystallasers clarified using omnidirectional bandstructure," Opt. Express 20, 21773-21783 (2012) [Non-patent document 3] Jason Geng, “Structured-light 3Dsurface imaging: a tutorial,” Advances in Optics and Photonics 3, pp. 128-160(2011) Summary of the Invention [Problem to be solved by the invention]

[0006] An integrable phase modulating (iPM) laser is known that outputs a desired optical image by phase modulation in a phase modulation layer. A semiconductor light-emitting device equipped with multiple iPM lasers can be used for a variety of applications. For example, by sequentially outputting optical images of periodic stripe patterns from each iPM laser and shifting the phases of the stripe patterns output from each iPM laser, it can be used for three-dimensional measurement. However, when the drive circuit described in Non-Patent Document 1 is applied to a semiconductor light-emitting device including multiple iPM lasers, multiple signal lines are required between the microcontroller and the digital-to-analog converter. Since multiple digital-to-analog converters are provided corresponding to each of the multiple iPM lasers, the total number of signal lines becomes enormous. In addition, the use of multiple operational amplifiers and multiple transistors can result in a large overall area for the drive circuit. Furthermore, multiple digital-to-analog converters, multiple operational amplifiers, and multiple transistors are provided corresponding to each of the multiple iPM lasers. As a result, power consumption (standby power) is also generated by the multiple digital-to-analog converters, multiple operational amplifiers, and multiple transistors corresponding to the inactive iPM lasers, raising concerns about heat generation due to the standby power. Depending on the application of the semiconductor light emitting device (for example, obtaining a stereoscopic image of the oral cavity in dentistry), it is required to reduce the amount of heat generated and to make the device compact.

[0007] An object of the present invention is to provide a semiconductor light emitting device that can reduce the amount of heat generated and also can be made smaller in size. [Means for solving the problem]

[0008] The semiconductor light-emitting device of the present invention is [1] "a semiconductor light-emitting device comprising: a plurality of iPM lasers each having a first surface and a second surface opposite to the first surface and outputting light from the first surface; and a drive circuit that supplies a drive current for causing each of the plurality of iPM lasers to emit light, wherein the drive circuit has a current source circuit common to the plurality of iPM lasers; a plurality of switch units provided corresponding to each of the plurality of iPM lasers and switching the drive current on / off; and a switch operating unit that operates each of the plurality of switch units individually."

[0009] In the semiconductor light-emitting device described in [1] above, by individually operating each of the multiple switch units using a switch operating unit, a drive current can be supplied to each iPM laser corresponding to each of the multiple switch units. If multiple current source circuits corresponding to each iPM laser were provided, even the current source circuits corresponding to iPM lasers that are not being driven would consume power (standby power) because the current source circuits themselves are still operating. In the semiconductor light-emitting device described in [1] above, the drive current is supplied based on the current generated by a common current source circuit, so the amount of heat generated by standby power can be reduced. Furthermore, because a common current source circuit is used, the number of current source circuits required can be reduced, allowing for a more compact semiconductor light-emitting device.

[0010] The semiconductor light-emitting device of the present invention may be [2] "the semiconductor light-emitting device according to the above [1], in which each of the plurality of switch units has a first switch and a second switch connected in series with the first switch, and the switch operating unit has a first shift register that operates the first switch and a second shift register that operates the second switch." According to the semiconductor light-emitting device according to [2], drive current can be supplied individually to only the iPM lasers for which both the first switch and the second switch are turned on. The first shift register can specify the iPM lasers to be driven, for example, by row, and the second shift register can specify the iPM lasers to be driven, for example, by column. This makes it easy to supply drive current individually to multiple iPM lasers arranged across multiple rows and columns.

[0011] The semiconductor light-emitting device of the present invention may be the semiconductor light-emitting device according to [1] or [2] above, wherein [3] the drive circuit further includes a plurality of current mirror circuits respectively corresponding to the plurality of iPM lasers, each of the plurality of current mirror circuits having a first current path and a second current path through which a current flows that is proportional to the magnitude of the current flowing through the first current path, the first current path being connected to the common current source circuit, the switch unit being provided on the first current path, and the second current path being connected to the iPM laser among the plurality of iPM lasers that corresponds to the current mirror circuit. According to the semiconductor light-emitting device according to [3], a drive current based on a current generated by the common current source circuit can be supplied to the iPM laser via the second current path.

[0012] The semiconductor light-emitting device of the present invention may be the semiconductor light-emitting device according to any one of [1] to [3] above, wherein [4] "the drive circuit further includes a plurality of oscillation prevention circuits respectively corresponding to the plurality of iPM lasers, each of the plurality of oscillation prevention circuits including: an NMOS-FET including a source terminal connected to an anode terminal of each of the plurality of iPM lasers and a drain terminal connected to a first constant potential line; a first PMOS-FET including a gate terminal connected to the source terminal of the NMOS-FET and a drain terminal connected to a second constant potential line having a lower potential than the first constant potential line; and a second PMOS-FET including a drain terminal connected to the source terminal of the first PMOS-FET, a source terminal connected to a third constant potential line having a higher potential than the second constant potential line, and a gate terminal, the second PMOS-FET supplying a current to the first PMOS-FET in accordance with an input voltage to the gate terminal, and the potential between the first PMOS-FET and the second PMOS-FET being supplied to the gate terminal of the NMOS-FET." According to the semiconductor light-emitting device according to [4], the provision of an oscillation prevention circuit can reduce a resonance constant (Q value). This suppresses ringing and peaking, enabling stable operation of the iPM laser.

[0013] The semiconductor light-emitting device of the present invention may be [5] "the semiconductor light-emitting device according to any one of the above [1] to [4], in which the value of the current generated by the common current source circuit is variable." According to the semiconductor light-emitting device according to [5], the magnitude of the drive current is variable, which changes the light intensity of each iPM laser, and as a result, it is possible to change the brightness of the optical image output from the multiple iPM lasers.

[0014] The semiconductor light-emitting device of the present invention may be the semiconductor light-emitting device according to [6] above, wherein "the common current source circuit further includes an operational amplifier having an input voltage supplied to one of a pair of input terminals, a transistor having a control terminal connected to the output terminal of the operational amplifier, and a resistor unit having one end connected to the current terminal of the transistor and the other input terminal of the operational amplifier and the other end connected to a fourth constant potential line, wherein the resistance value of the resistor unit is variable, and the switching operation of the multiple switch units is synchronized with the operation of changing the resistance value of the resistor unit." According to the semiconductor light-emitting device according to [6] above, the variable resistance value of the resistor unit changes the value of the current generated by the current source circuit. Furthermore, the synchronization of the switching operation of the multiple switch units with the operation of changing the resistance value of the resistor unit allows the value of the drive current supplied to each iPM laser to be set for each iPM laser.

[0015] The semiconductor light emitting device of the present invention may be [7] "the semiconductor light emitting device according to the above [6], wherein the resistance section includes a plurality of partial circuits connected in parallel between the one end and the other end of the resistance section, each of the plurality of partial circuits including a resistor and a third switch connected in series between the one end and the other end of the resistance section, and the switching operation of the plurality of switch sections and the switching operation of the third switch are synchronized." According to the semiconductor light emitting device according to [7], the resistance value of the resistance section can be made variable, and the switching operation of the plurality of switch sections can be synchronized with the operation of changing the resistance value of the resistance section.

[0016] The semiconductor light-emitting device of the present invention may be the semiconductor light-emitting device described in [5] above, wherein the common current source circuit further includes an operational amplifier having an input voltage supplied to one of a pair of input terminals, a transistor having a control terminal connected to the output terminal of the operational amplifier, and a resistor having one end connected to a current terminal of the transistor and the other input terminal of the operational amplifier and the other end connected to a fourth constant potential line, and wherein the switching operation of the plurality of switch units and the operation of switching the value of the input voltage are synchronized. According to the semiconductor light-emitting device described in [8], the value of the current generated by the current source circuit changes when the value of the input voltage is switched. Furthermore, because the switching operation of the plurality of switch units and the operation of switching the value of the input voltage are synchronized, the value of the drive current supplied to each iPM laser can be set for each iPM laser.

[0017] The semiconductor light emitting device of the present invention may be [9] "the semiconductor light emitting device according to the above [5], wherein the drive circuit further comprises a serial-to-parallel converter for converting a serial signal containing digital data representing an instruction value of a current for the common current source circuit into a parallel signal, and a digital-to-analog converter for converting the digital data converted into the parallel signal into an analog signal, and the common current source circuit generates a current having a magnitude corresponding to the instruction value based on the analog signal." According to the semiconductor light emitting device according to [9], digital data representing an instruction value of a current for the common current source circuit can be received as a serial signal from the outside, thereby reducing the number of wirings.

[0018] The semiconductor light-emitting device of the present invention is

[10] "each of the plurality of iPM lasers has an active layer which is a light-emitting portion, a phase modulation layer optically coupled to the active layer, a first clad layer located on the first surface side of the active layer and the phase modulation layer, a second clad layer located on the second surface side of the active layer and the phase modulation layer, a second electrode located on the second surface side of the second clad layer, and a first electrode located on the first surface side of the first clad layer, wherein the phase modulation layer has a basic layer and a plurality of modified refractive index layers which are provided in the basic layer so as to be two-dimensionally distributed on a plane perpendicular to the normal direction of the first surface, and which have refractive indices different from the refractive index of the basic layer." and a semiconductor light-emitting device according to any one of [1] to [9] above, wherein, in a state where a virtual square lattice is set on the surface, the plurality of modified refractive index areas are arranged such that the center of gravity of each of the plurality of modified refractive index areas is a predetermined distance away from the corresponding lattice point, and angles around each lattice point in the virtual square lattice, which are angles of line segments connecting the center of gravity of each of the plurality of modified refractive index areas to the corresponding lattice point, with respect to the virtual square lattice are set according to a phase distribution for forming an optical image, and at least two of the angles in the plurality of modified refractive index areas are different from each other. The semiconductor light-emitting device according to

[10] above can suitably realize an iPM laser.

[0019] The semiconductor light emitting device of the present invention is

[11] "each of the plurality of iPM lasers has an active layer which is a light emitting portion, a phase modulation layer optically coupled to the active layer, a first clad layer located on the first surface side of the active layer and the phase modulation layer, a second clad layer located on the second surface side of the active layer and the phase modulation layer, a second electrode located on the second surface side of the second clad layer, and a first electrode located on the first surface side of the first clad layer, wherein the phase modulation layer is provided in the basic layer so as to be two-dimensionally distributed on a plane perpendicular to a normal direction of the first surface, and the refractive index of the basic layer and and a plurality of modified refractive index areas having different refractive indices, wherein, in a state where a virtual square lattice is set on the surface, the plurality of modified refractive index areas are arranged so that the center of gravity of each of the plurality of modified refractive index areas passes through a corresponding lattice point and is located on a straight line inclined to the virtual square lattice, and the distance along the straight line between the center of gravity of each of the plurality of modified refractive index areas and the corresponding lattice point is set in accordance with a phase distribution for forming an optical image, and the slope of the straight line is uniform in the plurality of modified refractive index areas.The semiconductor light emitting device described in

[11] can suitably realize an iPM laser.

[0020] The semiconductor light-emitting device of the present invention may be

[12] "the semiconductor light-emitting device according to any one of the above [1] to

[11] , wherein each of the plurality of iPM lasers is monolithically formed." According to the semiconductor light-emitting device according to

[12] , the plurality of iPM lasers can be formed in a single element, which makes it possible to facilitate assembly of the semiconductor light-emitting device.

[0021] The semiconductor light-emitting device of the present invention may be

[13] "the semiconductor light-emitting device according to the above

[12] , in which the plurality of iPM lasers and the drive circuit are mounted on a common substrate." According to the semiconductor light-emitting device according to

[13] , the drive circuit and the plurality of monolithically formed iPM lasers can be integrated on a common substrate, thereby enabling further miniaturization of the device.

[0022] The semiconductor light emitting device of the present invention may be

[14] "the semiconductor light emitting device according to any one of the above [1] to

[11] , further comprising a support substrate including a third surface and a fourth surface opposite to the third surface, and the plurality of iPM lasers are individually mounted on the third surface with the second surface facing the third surface." According to the semiconductor light emitting device according to

[14] , the plurality of iPM lasers can be formed discretely on the support substrate.

[0023] The semiconductor light-emitting device of the present invention may be

[15] "the semiconductor light-emitting device according to the above

[14] , wherein the drive circuit is disposed on the third surface or the fourth surface of the support substrate." According to the semiconductor light-emitting device according to

[15] , the drive circuit and a plurality of iPM lasers formed discretely can be integrated on the support substrate, thereby enabling further miniaturization of the device.

[0024] The semiconductor light-emitting device of the present invention may be

[16] "the semiconductor light-emitting device according to any one of the above [1] to

[12] , wherein the drive circuit is connected to the plurality of iPM lasers by bump bonding." According to the semiconductor light-emitting device according to

[16] , the drive circuit and the plurality of iPM lasers can be integrated by connecting them by bump bonding, thereby enabling further miniaturization of the device. [Effects of the Invention]

[0025] According to the present invention, it is possible to provide a semiconductor light emitting device that can reduce the amount of heat generated and also can be made smaller in size. [Brief explanation of the drawings]

[0026] [Figure 1] FIG. 1 is a diagram illustrating the configuration of a semiconductor light emitting device according to an embodiment. [Figure 2] FIG. 2 is a plan view of the semiconductor light emitting device shown in FIG. [Figure 3]FIG. 3 is a schematic diagram showing a cross section of each iPM laser taken along line III-III shown in FIG. [Figure 4] FIG. 4 is a plan view of the phase modulation layer shown in FIG. [Figure 5] FIG. 5 is an enlarged view of a part (unit constituent region) of the phase modulation layer shown in FIG. [Figure 6] FIG. 6 is a diagram illustrating coordinate transformation from spherical coordinates to coordinates in an XYZ orthogonal coordinate system. [Figure 7] FIG. 7 is a plan view showing the reciprocal lattice space for the phase modulation layer of each iPM laser with M-point oscillation. [Figure 8] FIG. 8 is a conceptual diagram illustrating a state in which a diffraction vector is added to an in-plane wave vector. [Figure 9] FIG. 9 is a diagram for schematically explaining the structure around the light line. [Figure 10] FIG. 10 is a diagram conceptually showing an example of the rotation angle distribution. [Figure 11] FIG. 11 is a conceptual diagram for explaining a state in which a diffraction vector is added to the in-plane wave vector in the direction minus the wave number spread. [Figure 12] FIG. 12 is a plan view of a phase modulation layer according to a first modified example. [Figure 13] FIG. 13 is an enlarged view of a part (unit constituent region) of the phase modulation layer shown in FIG. [Figure 14] FIG. 14 is an overall block diagram of the drive circuit shown in FIG. [Figure 15] FIG. 15 is a circuit diagram of the drive circuit shown in FIG. [Figure 16] FIG. 16 is a detailed circuit diagram of the current source circuit shown in FIG. [Figure 17] FIG. 17 is a diagram showing a configuration of the switch operation unit shown in FIG. [Figure 18] FIG. 18 is a schematic diagram showing the configuration of a three-dimensional measuring device. [Figure 19]FIG. 19 is a diagram showing a sinusoidal stripe pattern formed by the three-dimensional measuring apparatus shown in FIG. [Figure 20] 20(a) and 20(b) are diagrams showing the first stripe element and the second stripe element. [Figure 21] 21(a) and 21(b) are diagrams showing the third and fourth stripe elements. [Figure 22] FIG. 22 is a diagram showing a stripe pattern generated by combining the first to fourth stripe elements. [Figure 23] 23(a) and 23(b) are diagrams showing the first stripe pattern and the second stripe pattern. [Figure 24] 24(a) and 24(b) are diagrams showing the third stripe pattern and the fourth stripe pattern. [Figure 25] 25(a) and 25(b) are diagrams showing current source circuits according to a first and second modified examples. [Figure 26] FIG. 26 is a side view of a semiconductor light emitting device according to a third modification. [Figure 27] FIG. 27 is a side view of a semiconductor light emitting device according to a fourth modification. [Figure 28] FIG. 28 is a partial cross-sectional view of a semiconductor light emitting device according to a fifth modification. [Figure 29] FIG. 29 is a partial cross-sectional view of a semiconductor light emitting device according to a sixth modification. [Figure 30] FIG. 30 is an exploded perspective view showing the configuration of a light source device according to the second embodiment of the present disclosure. [Figure 31] 31(a) and 31(b) are diagrams showing a schematic view of how light including stripe elements from four iPM lasers is projected onto a common projection area. [Figure 32] 32(a) and 32(b) are diagrams showing a schematic view of how light including stripe elements from four iPM lasers is projected onto a common projection area. [Figure 33]33(a) and 33(b) are diagrams schematically showing how light including stripe elements from four iPM lasers is projected onto a common projection area in the comparative example. [Figure 34] 34(a) and 34(b) are diagrams schematically showing how light including stripe elements from four iPM lasers is projected onto a common projection area in the comparative example. [Figure 35] FIG. 35 is a diagram for explaining the problem caused by the positional deviation of the emission line in the above comparative example. [Figure 36] FIG. 36 is a graph showing the relationship between the distance and the deviation of the central angle when the arrangement pitch is set to 0.25 mm in the formula (35). [Figure 37] 37(a) and 37(b) are diagrams for explaining a modified example of the second embodiment. [Figure 38] 38(a) and 38(b) are diagrams for explaining a modified example of the second embodiment. [Figure 39] 39(a) and 39(b) are diagrams for explaining a comparative example of a modified example of the second embodiment. [Figure 40] 40(a) and 40(b) are diagrams for explaining a comparative example of a modified example of the second embodiment. [Figure 41] 41(a) and 41(b) are diagrams for explaining another modified example of the second embodiment. [Figure 42] 42(a) and 42(b) are diagrams for explaining another modified example of the second embodiment. [Figure 43] FIG. 43 is a diagram showing the mutual conversion between decimal numbers, binary code, which is another way of expressing binary numbers, and Gray code. [Figure 44] FIG. 44 is a diagram showing an example of a combination of stripe patterns including a gray code. [Figure 45] FIG. 45 is a perspective view showing the configuration of a light source device according to the third embodiment of the present disclosure. [Figure 46]FIG. 46 is a perspective view showing the configuration of a light source device according to the third embodiment of the present disclosure. [Figure 47] FIG. 47 is a perspective view showing the configuration of a light source device according to a modified example of the third embodiment. [Figure 48] FIG. 48 is a perspective view showing the configuration of the light emitting and receiving module according to the fourth embodiment of the present disclosure. [Figure 49] FIG. 49 is a perspective view showing the configuration of a light receiving and emitting module according to a modified example of the fourth embodiment. [Figure 50] FIG. 50 is a perspective view showing the configuration of a light receiving and emitting module according to another modified example of the fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0027] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In each drawing, the same or corresponding parts are designated by the same reference numerals, and duplicated explanations will be omitted. (First embodiment) [Configuration of semiconductor light-emitting device]

[0028] FIG. 1 is a configuration diagram of a semiconductor light-emitting device 1 according to a first embodiment. As shown in FIG. 1, the semiconductor light-emitting device 1 includes a plurality of iPM lasers 2 and a drive circuit 3. Each of the plurality of iPM lasers 2 has a first surface 2a and a second surface 2b opposite (facing) the first surface 2a. The drive circuit 3 has a surface 3a facing the second surface 2b. The drive circuit 3 also includes a current source circuit 31, a plurality of current mirror circuits 32, and a switch operation unit 34. Each of the plurality of current mirror circuits 32 is electrically connected to each of the plurality of iPM lasers 2. The switch operation unit 34 is electrically connected to the plurality of iPM lasers 2. For example, electrical contacts corresponding to each of the plurality of current mirror circuits 32 and the switch operation unit 34 are formed on the surface 3a, and the plurality of current mirror circuits 32 and the switch operation unit 34 are connected to the plurality of iPM lasers 2 via the electrical contacts by bump bonding. The semiconductor light-emitting device 1 further includes a semiconductor region 2d and a semiconductor substrate 20. The semiconductor region 2d surrounds the multiple iPM lasers 2 in a ring shape. The multiple iPM lasers 2 are formed on the semiconductor substrate 20, which is made of a semiconductor such as GaAs. The semiconductor substrate 20 has a square or rectangular planar shape, and a first electrode 27 is formed at each of the four corners of the rear surface of the semiconductor substrate 20. The first electrode 27 forms ohmic contact with the rear surface of the semiconductor substrate 20 and defines a reference potential. In this manner, the multiple iPM lasers 2 are formed on the common semiconductor substrate 20. In other words, the multiple iPM lasers 2 are monolithically formed. Adjacent iPM lasers 2 are formed at a fixed interval. Each of the multiple iPM lasers 2 outputs laser light containing a desired optical image from its first surface 2a. A drive circuit 3 supplies a drive current to each of the multiple iPM lasers 2 to emit light. The semiconductor region 2d improves flatness by distributing the load applied to each iPM laser 2 when the iPM laser 2 is mounted on the drive circuit 3. In the following description, the direction perpendicular to the first surface 2a is referred to as the Z-axis direction, a direction parallel to the first surface 2a is referred to as the X-axis direction, and a direction perpendicular to both the Z-axis direction and the X-axis direction is referred to as the Y-axis direction.

[0029] 2 is a plan view of the semiconductor light-emitting device 1 shown in FIG. 2. The semiconductor region 2d is not shown in FIG. 2. The multiple iPM lasers 2 are arranged in a two-dimensional matrix with the X-axis direction and the Y-axis direction as the row direction and the column direction, respectively. In this embodiment, a total of 16 iPM lasers 2 are arranged, four in the X-axis direction (row direction) and four in the Y-axis direction (column direction). [iPM laser configuration]

[0030] 3 is a schematic diagram showing a cross section of each iPM laser 2 taken along line III-III in FIG. 2. Each iPM laser 2 forms a standing wave in an in-plane direction parallel to an imaginary plane formed by the X-axis and Y-axis directions, and outputs a phase-controlled plane wave in the Z-axis direction. As will be described later, light is output that forms a two-dimensional optical image of any shape along the normal direction (i.e., the Z-axis direction) of the main surface 20a of the semiconductor substrate 20, a tilt direction intersecting the normal direction, or both the normal direction and the tilt direction.

[0031] Each iPM laser 2 includes an active layer 22 as a light-emitting section provided on a semiconductor substrate 20, a phase modulation layer 25A optically coupled to the active layer 22, a first cladding layer 21 located on the first surface 2a side of the active layer 22 and the phase modulation layer 25A, a second cladding layer 23 located on the second surface 2b side of the active layer 22 and the phase modulation layer 25A, and a contact layer 24 provided on the second cladding layer 23. The semiconductor substrate 20, first cladding layer 21, active layer 22, second cladding layer 23, and contact layer 24 are made of compound semiconductors such as GaAs-based semiconductors, InP-based semiconductors, and nitride-based semiconductors. The energy bandgaps of the first cladding layer 21 and second cladding layer 23 are larger than the energy bandgap of the active layer 22. The thickness directions of the semiconductor substrate 20, first cladding layer 21, active layer 22, second cladding layer 23, and contact layer 24 coincide with the Z-axis direction.

[0032] In this embodiment, the phase modulation layer 25A is provided between the active layer 22 and the second cladding layer 23. The phase modulation layer 25A may be provided between the first cladding layer 21 and the active layer 22. If necessary, an optical guide layer may be provided at least one between the active layer 22 and the second cladding layer 23 and between the active layer 22 and the first cladding layer 21. The thickness direction of the phase modulation layer 25A coincides with the Z-axis direction. The optical guide layer may include a carrier barrier layer for efficiently confining carriers in the active layer 22.

[0033] An isolation region 2g is formed between adjacent iPM lasers 2. The isolation region 2g is a slit (gap) formed by either dry etching or wet etching, and an insulating film 28 such as SiN is formed on the sidewall of the slit to provide insulation, thereby suppressing current leakage due to soldering during assembly. Note that the isolation region 2g can also be formed by insulating a semiconductor layer modified by high-intensity light (electric field) or by impurity diffusion or ion implantation.

[0034] The phase modulation layer 25A includes a base layer 25a and multiple modified refractive index areas 25b. The base layer 25a is made of a first refractive index medium. Each modified refractive index area 25b is made of a second refractive index medium having a refractive index different from that of the first refractive index medium and is present in the base layer 25a. The two-dimensional arrangement of the multiple modified refractive index areas 25b includes a substantially periodic structure. When the equivalent refractive index of the mode is n, the wavelength λ0 (=(√2)×a×n, where a is the lattice spacing) selected by the phase modulation layer 25A is included in the emission wavelength range of the active layer 22. The phase modulation layer 25A can selectively output light having a band edge wavelength near the wavelength λ0 of the emission wavelengths of the active layer 22 to the outside. Laser light incident on the phase modulation layer 25A forms a predetermined mode in the phase modulation layer 25A corresponding to the arrangement of the modified refractive index areas 25b and is emitted to the outside from the first surface 2a as a laser beam having a desired pattern.

[0035] Each iPM laser 2 further includes a second electrode 26 provided on the contact layer 24 and a first electrode 27 (see FIG. 1) provided on the back surface 20b of the semiconductor substrate 20. The second electrode 26 is located on the second surface 2b side of the second cladding layer 23 and forms ohmic contact with the contact layer 24. The first electrode 27 is located on the first surface 2a side of the first cladding layer 21 and forms ohmic contact with the semiconductor substrate 20. The second electrode 26 is provided in a central region of the contact layer 24. The portion of the contact layer 24 other than the second electrode 26 is covered with an insulating film 28. Note that the contact layer 24 not in contact with the second electrode 26 may be removed. The portion of the back surface 20b of the semiconductor substrate 20 other than the first electrode 27 is covered with an anti-reflection film 29.

[0036] When a driving current is supplied between the second electrode 26 and the first electrode 27, recombination of electrons and holes occurs in the active layer 22, and light is emitted within the active layer 22. The electrons and holes that contribute to light emission within the active layer 22, as well as the generated light, are efficiently confined between the first cladding layer 21 and the second cladding layer 23.

[0037] The light output from the active layer 22 enters the phase modulation layer 25A and forms a predetermined mode corresponding to the lattice structure inside the phase modulation layer 25A. The laser light output from the phase modulation layer 25A is either directly output from the rear surface 20b through the opening 27a to the outside of each iPM laser 2, or is reflected by the second electrode 26 and then output from the rear surface 20b through the opening 27a to the outside of each iPM laser 2. At this time, the signal light contained in the laser light is output along the normal direction to the main surface 20a, or along an inclined direction intersecting the normal direction, or along both directions. Of the output light, it is the signal light that forms the desired optical image. The signal light is mainly 1st-order light and −1st-order light.

[0038] FIG. 4 is a plan view of the phase modulation layer 25A shown in FIG. 3. The phase modulation layer 25A includes a base layer 25a and multiple modified refractive index areas 25b. The base layer 25a is made of a first refractive index medium. The multiple modified refractive index areas 25b are made of a second refractive index medium having a refractive index different from that of the first refractive index medium. Here, a virtual square lattice is set on one surface of the phase modulation layer 25A, which coincides with a plane parallel to the plane formed by the X-axis direction and the Y-axis direction. One side of the square lattice is parallel to the X-axis, and the other side is parallel to the Y-axis. In this case, square unit constituent regions R(x, y) centered on a lattice point O of the square lattice can be set two-dimensionally over multiple columns (x = 0, 1, 2, 3, . . . ) along the X-axis and multiple rows (y = 0, 1, 2, . . . ) along the Y-axis. If the XY coordinates of each unit constituent region R are given by the position of the center of gravity of each unit constituent region R, the position of the center of gravity coincides with lattice point O of a virtual square lattice. A plurality of modified refractive index regions 25b are provided, for example, one per unit constituent region R. The planar shape of the modified refractive index region 25b is, for example, a circular shape. The lattice point O may be located outside the modified refractive index region 25b or may be included inside the modified refractive index region 25b.

[0039] The ratio of the area S of the modified refractive index area 25b to one unit constituent area R is called a filling factor (FF). When the lattice spacing of the square lattice is a, the filling factor FF of the modified refractive index area 25b is S / a 2 S is the area of ​​the modified refractive index area 25b in the XY plane, and for example, if the shape of the modified refractive index area 25b is a perfect circle, S=π(d / 2) where d is the diameter of the perfect circle. 2 In addition, when the shape of the modified refractive index area 25b is a square, S=LA where LA is the length of one side of the square. 2 is given as:

[0040] FIG. 5 is an enlarged view of a portion (unit region R) of the phase modulation layer 25A shown in FIG. 4. As shown in FIG. 5, each modified refractive index area 25b has a center of gravity G, and the position of the center of gravity G in the unit region R is given by the s-axis and t-axis, which are orthogonal to each other, at the lattice point O. Here, in the unit region R(x, y) defined by the s-axis and t-axis, which are orthogonal to each other, the angle formed by the vector from the lattice point O(x, y) toward the center of gravity G and the s-axis is defined as φ(x, y). Note that x indicates the position of the xth lattice point along the X-axis, and y indicates the position of the yth lattice point along the Y-axis. When the angle φ is 0°, the direction of the vector connecting the lattice point O(x, y) and the center of gravity G coincides with the positive direction of the X-axis. Furthermore, the length of the vector connecting the lattice point O(x, y) and the center of gravity G is defined as r(x, y). In one example, r(x, y) is constant regardless of x and y (throughout the phase modulation layer 25A).

[0041] As shown in FIG. 4, the direction of the vector connecting the lattice point O(x,y) and the center of gravity G (the center of gravity of the corresponding modified refractive index area 25b), i.e., the angle φ of the center of gravity G of the modified refractive index area 25b around the lattice point, is individually set for each lattice point O(x,y) according to a phase pattern corresponding to the desired optical image. The phase pattern, i.e., the angle φ(x,y), has a specific value for each position determined by the values ​​of x and y, but is not necessarily expressed by a specific function. That is, the angle φ(x,y) is determined from a phase distribution extracted from a complex amplitude distribution obtained by performing an inverse Fourier transform on the desired optical image. At least two of the angles φ in the multiple modified refractive index areas 25b are different from each other. Note that when calculating the complex amplitude distribution from the desired optical image, applying an iterative algorithm such as the Gerchberg-Saxton (GS) method, which is commonly used in calculations for hologram generation, can improve the reproducibility of the beam pattern.

[0042] The beam pattern output from the phase modulation layer 25A includes, for example, a striped pattern. To obtain a desired beam pattern, the distribution of angles φ(x, y) of the modified refractive index areas 25b in the phase modulation layer 25A is determined by the following procedure.

[0043] As a first prerequisite, in an XYZ orthogonal coordinate system defined by a Z axis coinciding with the normal direction and an XY plane coinciding with one surface of a phase modulation layer 25A including multiple modified refractive index areas 25b, a virtual square lattice consisting of M1 (an integer greater than or equal to 1) × N1 (an integer greater than or equal to 1) unit constituent areas R having a square shape is set on the XY plane.

[0044] The second prerequisite is that the coordinates (ξ,η,ζ) in the XYZ Cartesian coordinate system are the length of the radius r and the tilt angle θ from the Z axis, as shown in Figure 6. tilt and the rotation angle θ from the X-axis specified on the XY plane rot and the spherical coordinates (r,θ rot ,θ tilt ) satisfy the relationships shown in the following formulas (1) to (3). rot ,θ tilt ) to coordinates (ξ,η,ζ) in the XYZ Cartesian coordinate system, and the coordinates (ξ,η,ζ) represent a designed light image on a predetermined plane set in the XYZ Cartesian coordinate system, which is real space.

[0045] The beam pattern corresponding to the light image output from each iPM laser 2 is set at an angle θ tilt and θ rot When the set of bright spots is directed in the direction specified by the angle θ tilt and θ rot is the normalized wave number defined by the following equation (4) and corresponds to the X axis. x Coordinate value on axis k x and the normalized wave number defined by the following equation (5), which corresponds to the Y axis and is K x K perpendicular to the axis y Coordinate value on axis k y The normalized wave number is the wave number normalized by setting the wave number 2π / a, which corresponds to the lattice spacing of a virtual square lattice, to 1.0. In this case, K x axis and K yIn the wavenumber space defined by the axes, a specific wavenumber range including a beam pattern corresponding to an optical image is composed of M2 (an integer equal to or greater than 1) × N2 (an integer equal to or greater than 1) square image regions FR. Note that the integer M2 does not have to match the integer M1. Similarly, the integer N2 does not have to match the integer N1. Furthermore, equations (4) and (5) are disclosed in, for example, Non-Patent Document 2.

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[0046] The third prerequisite is that in wave number space, K x Axial coordinate component k x (an integer between 0 and M2-1) and K y Axial coordinate component k y (an integer between 0 and N2-1) and the image region FR(k x ,k y) to a unit constituent region R(x,y) on the XY plane specified by its coordinate component x (an integer between 0 and M1-1) in the X-axis direction and its coordinate component y (an integer between 0 and N1-1) in the Y-axis direction. The complex amplitude F(x,y) obtained by performing a two-dimensional inverse discrete Fourier transform on each of these components is given by the following equation (6), where j is the imaginary unit. The complex amplitude F(x,y) is defined by the following equation (7), where the amplitude term is A(x,y) and the phase term is P(x,y). As a fourth prerequisite, the unit constituent region R(x,y) is defined by the s-axis and t-axis, which are parallel to the X-axis and Y-axis, respectively, and are orthogonal to each other at the lattice point O(x,y) that is the center of the unit constituent region R(x,y).

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[0047] Under the above first to fourth prerequisites, the phase modulation layer 25A is configured to satisfy the following fifth and sixth conditions. That is, the fifth condition is satisfied when the center of gravity G is arranged in a state separated from the lattice point O(x, y) in the unit constituent region R(x, y). The sixth condition is satisfied when, in a state where the length r(x, y) of the line segment from the lattice point O(x, y) to the corresponding center of gravity G is set to a common value in each of the M1×N1 unit constituent regions R, the angle φ(x, y) formed by the line segment connecting the lattice point O(x, y) and the corresponding center of gravity G and the s-axis is φ(x,y)=C×P(x,y)+B C: proportionality constant, e.g., 180° / π B: Any constant, e.g., 0 This is satisfied by arranging the corresponding modified refractive index area 25b within the unit constituent area R(x, y) so as to satisfy the following relationship.

[0048] Each iPM laser 2 may oscillate at either the Γ-point or the M-point. Next, we will explain the M-point oscillation of each iPM laser 2. For each iPM laser 2 to oscillate at the M-point, the lattice spacing a of a virtual square lattice, the emission wavelength λ of the active layer 22, and the equivalent refractive index n of the mode should satisfy the condition λ = (√2)n × a. Figure 7 is a plan view showing the reciprocal lattice space for the phase modulation layer of each iPM laser 2 for M-point oscillation. Point P in the figure represents a reciprocal lattice point. Arrow B1 in the figure represents the fundamental reciprocal lattice vector, and arrows K1, K2, K3, and K4 represent four in-plane wave vectors. Each of the in-plane wave vectors K1 to K4 has a wavenumber spread SP due to the rotation angle distribution φ(x, y).

[0049] The shape and size of the wavenumber spread SP are the same as in the case of the Γ-point oscillation described above. In each iPM laser 2 with M-point oscillation, the magnitude of the in-plane wavenumber vectors K1 to K4 (i.e., the magnitude of the standing wave in the in-plane direction) is smaller than the magnitude of the primitive reciprocal lattice vector B1. Therefore, the vector sum of the in-plane wavenumber vectors K1 to K4 and the primitive reciprocal lattice vector B1 does not become 0, and the wavenumber in the in-plane direction cannot become 0 due to diffraction, so diffraction does not occur in the direction perpendicular to the plane (Z-axis direction). In this state, each iPM laser 2 with M-point oscillation does not output a zeroth-order light in the direction perpendicular to the plane (Z-axis direction), or a first-order light and a -first-order light in a direction inclined with respect to the Z-axis direction.

[0050] In this embodiment, by applying the following technique to the phase modulation layer 25A in each iPM laser 2 with M-point oscillation, it is possible to output a part of the first-order light and the -1st-order light without outputting the zeroth-order light. Specifically, as shown in Fig. 8, by adding a diffraction vector V having a certain magnitude and direction to the in-plane wave vectors K1 to K4, the magnitude of at least one of the in-plane wave vectors K1 to K4 (in the figure, the in-plane wave vector K3) is made smaller than 2π / λ. In other words, at least one of the in-plane wave vectors K1 to K4 (the in-plane wave vector K3) after the diffraction vector V is added is contained within a circular region (light line) LL with a radius of 2π / λ.

[0051] In FIG. 8, the in-plane wave vectors K1 to K4 indicated by dashed lines represent the wave vectors before the addition of the diffraction vector V, while the in-plane wave vectors K1 to K4 indicated by solid lines represent the wave vectors after the addition of the diffraction vector V. The light line LL corresponds to the total reflection condition, and a wave vector whose magnitude falls within the light line LL has a component in the direction perpendicular to the surface (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 within the range from 2π / (√2)a-2π / λ to 2π / (√2)a+2π / λ, and is, for example, 2π / (√2)a.

[0052] Next, we will consider the magnitude and direction of the diffraction vector V for placing at least one of the in-plane wave vectors K1 to K4 within the light line LL. The following formulas (8) to (11) show the in-plane wave vectors K1 to K4 before the diffraction vector V is added.

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[0053] When the diffraction vector V is expressed as in the following formula (14), the in-plane wave number vectors K1 to K4 after the diffraction vector V is added are expressed as the following formulas (15) to (18).

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[0054] In the formulas (15) to (18), if it is considered that any of the wave vectors K1 to K4 falls within the light line LL, the relationship of the following formula (19) holds.

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[0055] The size (radius) of the light line LL is set to 2π / λ for the following reason. Figure 9 is a diagram for schematically explaining the structure surrounding the light line LL. The figure shows the boundary between the device and air as viewed from a direction perpendicular to the Z-axis direction. The magnitude of the wave vector of light in a vacuum is 2π / λ, but when light propagates through a device medium as shown in Figure 9, the magnitude of the wave vector Ka within the medium with a refractive index of n is 2πn / λ. In this case, in order for light to propagate through the boundary between the device and air, the wave number components parallel to the boundary must be continuous (law of conservation of wave number).

[0056] In Figure 9, when the wave vector Ka forms an angle θ with the Z axis, the length of the wave vector Kb projected onto the plane (i.e., the in-plane wave vector) is (2πn / λ) sin θ. However, due to the relationship where the refractive index of the medium is generally n>1, the law of conservation of wave numbers no longer holds when the in-plane wave vector Kb in the medium is at an angle greater than 2π / λ. In this case, the light is totally reflected and cannot be extracted to the air side. The magnitude of the wave vector corresponding to this total reflection condition is the magnitude of the light line LL, i.e., 2π / λ.

[0057] As a specific example of a method for adding the diffraction vector V to the in-plane wave vectors K1 to K4, a method can be considered in which a rotation angle distribution φ2(x,y) (second phase distribution) unrelated to the optical image is superimposed on a rotation angle distribution φ1(x,y) (first phase distribution), which is a phase distribution according to the optical image. In this case, the rotation angle distribution φ(x,y) of the phase modulation layer 25A is expressed as φ(x,y) = φ1(x,y) + φ2(x,y). As mentioned above, φ1(x,y) corresponds to the phase of the complex amplitude when the optical image is Fourier transformed. Furthermore, φ2(x,y) is the rotation angle distribution for adding the diffraction vector V that satisfies the above formula (19).

[0058] 10 is a diagram conceptually illustrating an example of the rotation angle distribution φ2(x,y). In the example of the figure, the first phase value φ A and a first phase value φ A a second phase value φ different from B In one example, the phase values ​​φ A is 0 (rad), and the phase value φ B is π (rad). In this case, the first phase value φ A and a second phase value φ B and change in increments of π. Such an arrangement of phase values ​​makes it possible to preferably realize a diffraction vector V along the Γ-M1 axis or the Γ-M2 axis. In the case of a checkerboard arrangement, V = (±π / a, ±π / a), and the diffraction vector V and the wave vectors K1 to K4 in Figure 7 exactly cancel each other out. The angular distribution φ2(x,y) of the diffraction vector V is expressed as the dot product of the diffraction vector V(Vx,Vy) and the position vector r(x,y). In other words, the angular distribution φ2(x,y) of the diffraction vector V is expressed as φ2(x,y) = V r = Vxx + Vyy.

[0059] In the above-described embodiment, when the wavenumber spread based on the angular spread of the optical image is contained in a circle of radius Δk centered at a certain point in wavenumber space, it can be simply considered as follows: By adding a diffraction vector V to the four-directional in-plane wavenumber vectors K1 to K4, the magnitude of at least one of the four-directional in-plane wavenumber vectors K1 to K4 is made smaller than 2π / λ (light line LL). This can be considered as making the magnitude of at least one of the four-directional in-plane wavenumber vectors K1 to K4 smaller than the value {(2π / λ)-Δk} obtained by subtracting the wavenumber spread Δk from 2π / λ by adding the diffraction vector V to the four-directional in-plane wavenumber vectors K1 to K4.

[0060] FIG. 11 is a diagram conceptually illustrating the above state. As shown in the figure, when a diffraction vector V is added to the in-plane wave vectors K1 to K4 excluding the wave number spread Δk, the magnitude of at least one of the in-plane wave vectors K1 to K4 becomes smaller than {(2π / λ)-Δk}. In FIG. 11, region LL2 is a circular region with a radius of {(2π / λ)-Δk}. In FIG. 11, the in-plane wave vectors K1 to K4 indicated by dashed lines represent the state before the addition of the diffraction vector V, while the in-plane wave vectors K1 to K4 indicated by solid lines represent the state after the addition of the diffraction vector V. Region LL2 corresponds to the total reflection condition taking into account the wave number spread Δk, and wave vectors whose magnitude falls within region LL2 also propagate in the direction perpendicular to the surface (Z-axis direction).

[0061] In this embodiment, the magnitude and direction of the diffraction vector V for placing at least one of the in-plane wave vectors K1 to K4 within the region LL2 will be described. The following formulas (20) to (23) show the in-plane wave vectors K1 to K4 before the diffraction vector V is added.

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[0062] Here, when the diffraction vector V is expressed as in the above-mentioned formula (14), the in-plane wave number vectors K1 to K4 after the diffraction vector V is added are expressed by the following formulas (24) to (27).

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[0063] In formulas (24) to (27), if it is considered that any of the in-plane wave vectors K1 to K4 falls within region LL2, the relationship of the following formula (28) holds. That is, by adding a diffraction vector V that satisfies formula (28), any of the in-plane wave vectors K1 to K4 excluding the wave number spread Δk falls within region LL2. Even in such a case, it is possible to output a part of the 1st order light and the −1st order light without outputting the 0th order light.

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[0064] FIG. 12 is a plan view of a phase modulation layer 25B according to a modified example. FIG. 13 is a diagram showing the positional relationship of modified refractive index areas in a phase modulation layer 25B according to a modified example. The phase modulation layer 25A may be replaced with the phase modulation layer 25B. As shown in FIGS. 12 and 13, the center of gravity G of each modified refractive index area 25b of the phase modulation layer 25B according to the modified example is located on a straight line D. The straight line D passes through a lattice point O corresponding to each unit constituent area R and is inclined with respect to each side of the square lattice. In other words, the straight line D 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 of the square lattice (the X-axis) is θ.

[0065] The tilt angle θ is constant within the phase modulation layer 25B. The tilt angle θ satisfies 0°<θ<90°, and in one example, θ=45°. Alternatively, the tilt angle θ satisfies 180°<θ<270°, and in one example, θ=225°. When the tilt 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 Y-axis. The tilt angle θ satisfies 90°<θ<180°, and in one example, θ=135°. Alternatively, the tilt angle θ satisfies 270°<θ<360°, and in one example, θ=315°. When the tilt 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. Thus, the tilt angle θ is an angle excluding 0°, 90°, 180°, and 270°.

[0066] Here, the distance between lattice point O and center of gravity G is r(x, y). x is the position of the xth lattice point on the X axis, and y is the position of the yth lattice point on the Y axis. When the distance r(x, y) is a positive value, the center of gravity G is located in the first quadrant (or the second quadrant). When the distance r(x, y) is a negative value, 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 center of gravity G coincide with each other. The tilt angles are preferably 45°, 135°, 225°, or 275°. At these tilt angles, only two of the four wave vectors (e.g., in-plane wave vectors (±π / a, ±π / a)) that form the standing wave at point M are phase-modulated, and the other two are not, thereby forming a stable standing wave.

[0067] The distance r(x, y) between the center of gravity G of each modified refractive index area and the lattice point O corresponding to each unit constituent area R is set individually for each modified refractive index area 15b according to a phase pattern corresponding to the desired optical image. The phase pattern, i.e., the distribution of distances r(x, y), has a specific value for each position determined by the values ​​of x and y, but is not necessarily expressed by a specific function. The distribution of distances r(x, y) is determined from the phase distribution extracted from the complex amplitude distribution obtained by performing an inverse Fourier transform on the desired optical image.

[0068] That is, as shown in Fig. 13, when the phase P(x,y) at a certain coordinate (x,y) is P0, the distance r(x,y) is set to 0, when the phase P(x,y) is π+P0, the distance r(x,y) is set to the maximum value R0, and when the phase P(x,y) is -π+P0, the distance r(x,y) is set to the minimum value -R0. For phases P(x,y) in between, the distance r(x,y) is set so that r(x,y) = {P(x,y) - P0} × R0 / π. The initial phase P0 can be set arbitrarily.

[0069] If the lattice spacing of a virtual square lattice is a, then the maximum value R0 of r(x, y) falls within the range of the following equation (29), for example: When determining the complex amplitude distribution from a desired optical image, it is possible to improve the reproducibility of the beam pattern by applying an iterative algorithm such as the Gerchberg-Saxton (GS) method, which is commonly used in calculations for generating holograms.

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[0070] In this embodiment, a desired optical image can be obtained by determining the distribution of the distance r(x, y) of the modified refractive index area 25b of the phase modulation layer 25B. Under the same first to fourth preconditions as in the above-described embodiment, the phase modulation layer 25B is configured to satisfy the following condition. That is, the distance r(x, y) from the lattice point O(x, y) to the center of gravity G of the corresponding modified refractive index area 25b is r(x,y)=C×(P(x,y)-P0) C: proportionality constant, e.g. R0 / π P0: Any constant, e.g., 0 The corresponding modified refractive index area 25b is arranged within the unit constituent area R(x, y) so as to satisfy the following relationship.

[0071] That is, the distance r(x, y) is set to 0 when the phase P(x, y) at a certain coordinate (x, y) is P0, set to the maximum value R0 when the phase P(x, y) is π+P0, and set to the minimum value -R0 when the phase P(x, y) is -π+P0. To obtain a desired optical image, the optical image may be subjected to an inverse Fourier transform, and a distribution of distances r(x, y) according to the phase P(x, y) of the complex amplitude may be provided to the multiple modified refractive index areas 25b. The phase P(x, y) and the distance r(x, y) may be proportional to each other.

[0072] In this embodiment, similarly to the above-described embodiment, the lattice spacing a of the virtual square lattice and the emission wavelength λ of the active layer 12 satisfy the condition for M-point oscillation. Furthermore, when considering the reciprocal lattice space in the phase modulation layer 25B, the magnitude of at least one of the four in-plane wave vectors each including the wave number spread due to the distribution of the distance r(x, y) can be made smaller than 2π / λ (light line).

[0073] In this embodiment, the following device is applied to the phase modulation layer 25B in each iPM laser 2 oscillating at point M, so that the zeroth-order light is not output within the light line, and a portion of the first-order light and a portion of the minus first-order light are output. Specifically, as shown in FIG. 8, a diffraction vector V having a certain magnitude and direction is added to the in-plane wave vectors K1 to K4, so that the magnitude of at least one of the in-plane wave vectors K1 to K4 is made smaller than 2π / λ. That is, after the diffraction vector V is added, at least one of the in-plane wave vectors K1 to K4 is contained within a circular region (light line) LL with a radius of 2π / λ. By adding the diffraction vector V that satisfies the above-mentioned formula (19), one of the in-plane wave vectors K1 to K4 is contained within the light line LL, and a portion of the first-order light and a portion of the minus first-order light are output.

[0074] 11, by adding a diffraction vector V to the four-directional in-plane wave vectors K1 to K4 minus the wave number spread Δk (i.e., the four-directional in-plane wave vectors in an M-point lasing square lattice PCSEL), the magnitude of at least one of the four in-plane wave vectors K1 to K4 may be made smaller than the value obtained by subtracting the wave number spread Δk from 2π / λ, i.e., {(2π / λ)-Δk}. That is, by adding a diffraction vector V that satisfies the above-mentioned formula (28), any of the in-plane wave vectors K1 to K4 falls within the region LL2, and part of the 1st-order light and part of the −1st-order light are output.

[0075] As an example of a specific method for adding the diffraction vector V to the in-plane wave vectors K1 to K4, a method of superimposing a distance distribution r2(x,y) (second phase distribution) unrelated to the optical image on a distance distribution r1(x,y) (first phase distribution), which is a phase distribution according to the optical image, can be considered. In this case, the distance distribution r(x,y) of the phase modulation layer 25B is expressed as r(x,y) = r1(x,y) + r2(x,y). As described above, r1(x,y) corresponds to the phase of the complex amplitude when the optical image is Fourier transformed. r2(x,y) is a distance distribution for adding the diffraction vector V that satisfies the above formula (19) or formula (28). Note that a specific example of the distance distribution r2(x,y) is the same as that shown in FIG. 10. [Drive circuit configuration]

[0076] FIG. 14 is an overall block diagram of the drive circuit 3 shown in FIG. 1. As shown in FIG. 14, the drive circuit 3 includes a current source circuit 31, multiple current mirror circuits 32, multiple oscillation prevention circuits 33, and a switch operation unit 34. The drive circuit 3 is electrically connected to an external control circuit 4 provided outside the semiconductor light-emitting device 1 and is driven in response to instruction signals S1 to S3 from the external control circuit 4. The current source circuit 31 generates an operating current Iop that is the basis of a drive current Iout for causing each iPM laser 2 to emit light. The current source circuit 31 receives an instruction signal S1 from the external control circuit 4 and generates an operating current Iop having a current value based on the instruction signal S1. The current source circuit 31 is common to multiple iPM lasers 2. A wire extending from an output terminal of the current source circuit 31 branches into multiple branches, and the multiple branched wires are connected to input terminals of multiple current mirror circuits 32, respectively. The multiple current mirror circuits 32 amplify the operating current Iop generated by the current source circuit 31 to generate a drive current Iout, which is then supplied to each iPM laser 2. The output terminals of the multiple current mirror circuits 32 are connected to each iPM laser 2. The number of the multiple current mirror circuits 32 is the same as the number of the multiple iPM lasers 2. The output terminals of the multiple current mirror circuits 32 are also connected to multiple oscillation prevention circuits 33.

[0077] The oscillation prevention circuits 33 suppress ringing caused by parasitic components (inductance components) in the wiring between each current mirror circuit 32 and each iPM laser 2. The number of oscillation prevention circuits 33 is the same as the number of iPM lasers 2 and the number of current mirror circuits 32. The switch operation unit 34 includes a first shift register 34a and a second shift register 34b. The first shift register 34a receives an instruction signal S2 from the external control circuit 4. The first shift register 34a switches on / off the supply of drive current Iout to each of the iPM lasers 2 for each column based on the instruction signal S2. The second shift register 34b receives an instruction signal S3 from the external control circuit 4. The second shift register 34b switches on / off the supply of drive current Iout to each of the iPM lasers 2 for each row based on the instruction signal S3. The drive current Iout is switched on / off for each individual iPM laser 2 by both the first shift register 34a and the second shift register 34b, and when the drive current Iout is turned on, the drive current Iout is supplied to each iPM laser 2.

[0078] 15 is a circuit diagram of the drive circuit 3 shown in FIG. 1. As shown in FIG. 15, the current source circuit 31 includes an operational amplifier 311, an NMOS-FET (transistor) 312, a voltage source 313, and a resistor Rop. The current source circuit 31 in this embodiment is a sink-type constant current circuit because it uses the NMOS-FET 312. The drain terminal of the NMOS-FET 312 is connected to the input terminal of the current mirror circuit 32. The gate terminal (control terminal) of the NMOS-FET 312 is connected to the output terminal of the operational amplifier 311. The operational amplifier 311 has a pair of input terminals, that is, an inverting input terminal and a non-inverting input terminal. A voltage source 313 is connected to the non-inverting input terminal (one of the pair of input terminals) of the operational amplifier 311, and an input voltage Vop is supplied to the non-inverting input terminal. The source terminal (current terminal) of the NMOS-FET 312 is connected to the inverting input terminal (the other of the pair of input terminals) of the operational amplifier 311 and to the reference potential line GND (fourth constant potential line) via the resistor unit Rop. Due to the imaginary short of the operational amplifier 311, a voltage equal to the input voltage Vop (for convenience, illustrated as Vop) is applied to a node N between the source terminal of the NMOS-FET 312 and the resistor unit Rop. Therefore, the operating current Iop has a current value calculated by dividing the resistance value of the resistor unit Rop from the voltage value of the input voltage Vop. One or both of the resistance value of the resistor unit Rop and the voltage value of the input voltage Vop output from the voltage source 313 are variable. The current value of the operating current Iop changes as the voltage value of the input voltage Vop or the resistance value of the resistor unit Rop changes. Therefore, the operating current Iop is variable. Note that the current source circuit 31 may function as a sweep-out type constant current circuit by providing a PMOS-FET instead of the NMOS-FET 312. In this case, the resistance unit Rop is connected between the source terminal of the PMOS-FET and the input terminal of each current mirror circuit 32. Also, a bipolar transistor may be provided instead of the NMOS-FET or PMOS-FET.

[0079] Each current mirror circuit 32 includes a transistor circuit 321 and a switch unit 322. In the example of FIG. 15, the transistor circuit 321 includes a PMOS-FET 321a and a PMOS-FET 321b. The gate terminal of the PMOS-FET 321a and the gate terminal of the PMOS-FET 321b are connected to one another. The source terminal of the PMOS-FET 321a and the source terminal of the PMOS-FET 321b are connected to one another. A voltage source 325 is connected to the shared source terminal. The switch unit 322 includes a first switch 322a and a second switch 322b. The first switch 322a and the second switch 322b are connected to one another in series. The switch unit 322 is turned on / off individually for each current mirror circuit 32 in response to an instruction signal from the switch operating unit 34. The first switch 322a is electrically connected to the first shift register 34a (see FIG. 14). The first switch 322a is switched on / off in response to an instruction signal S2 from the first shift register 34a. The second switch 322b is electrically connected to the second shift register 34b (see FIG. 14). The second switch 322b is switched on / off in response to an instruction signal S3 from the second shift register 34b. When both the first switch 322a and the second switch 322b are turned on, an operating current Iop is supplied to each current mirror circuit 32.

[0080] FIG. 16 is a detailed circuit diagram of the current source circuit 31 shown in FIG. 15. As shown in FIG. 16, the resistor unit Rop includes multiple partial circuits 316a to 316d. One end of the resistor unit Rop is connected to the source terminal of the NMOS-FET 312 and the inverting input terminal of the operational amplifier 311, and the other end of the resistor unit Rop is connected to the reference potential line GND. The multiple partial circuits 316a to 316d are connected in parallel between one end and the other end of the resistor unit Rop. The partial circuit 316a includes a resistor Rop1 and a third switch 314a connected in series. The partial circuit 316b includes a resistor Rop2 and a third switch 314b connected in series. The partial circuit 316c includes a resistor Rop3 and a third switch 314c connected in series. The partial circuit 316d includes a resistor Rop4 and a third switch 314d connected in series. In the example of FIG. 16, four third switches 314a to 314d and four resistors Rop1 to Rop4 are provided. Each of the third switches 314a to 314d is directly connected to each of the resistors Rop1 to Rop4 via wiring alone. The third switches 314a to 314d receive an instruction signal S1 from the external control circuit 4 (see FIG. 14) for switching on / off at least one of the third switches 314a to 314d. Depending on which of the third switches 314a to 314d is turned on, at least one of the resistors Rop1 to Rop4 is connected to the source terminal of the NMOS-FET 312. This changes the value of the operating current Iop. For example, when only the third switch 314a is turned on, the operating current Iop has a constant current value calculated by dividing the resistance of the resistor Rop1 by the voltage value of the input voltage Vop. On the other hand, when the third switches 314a and 314c are turned on, the operating current Iop has a constant current value calculated by dividing the combined resistance value of the resistors Rop1 and Rop3 from the voltage value of the input voltage Vop.

[0081] The external control circuit 4 sequentially switches on / off at least one of the multiple third switches 314a-314d at a constant cycle (e.g., several kHz to several GHz). The switching order may be a predetermined order or a random order. For example, the external control circuit 4 switches on / off at least one of the multiple third switches 314a-314d for each column of multiple iPM lasers 2, thereby switching the value of the drive current Iout. The external control circuit 4 may switch the value of the drive current Iout for each iPM laser 2. Furthermore, the external control circuit 4 switches the multiple third switches 314a-314d in synchronization with the switching timing of the first switch 322a and the second switch 322b of each current mirror circuit 32. As a result, the multiple iPM lasers 2 are individually driven, and the value of the drive current Iout supplied to each is simultaneously switched. In other words, the switching operations of the first switch 322a and the second switch 322b are synchronized with the operation of changing the resistance value of the resistor section Rop (the switching operations of the third switches 314a to 314d).

[0082] Referring again to FIG. 15, each current mirror circuit 32 has a first current path 323 including a PMOS-FET 321a and multiple switch units 322, and a second current path 324 including a PMOS-FET 321b. The first current path 323 is connected to the drain terminal of the NMOS-FET 312 of the current source circuit 31. The second current path 324 is connected to each iPM laser 2. When both the first switch 322a and the second switch 322b are turned on, an operating current Iop flows through the first current path 323. Because the gate-source voltage Vgs is common to the PMOS-FET 321a and the PMOS-FET 321b, the operating current Iop also flows through the second current path 324. However, a drive current Iout, which is the operating current Iop amplified by N times (N is a real number), flows through the PMOS-FET 321b. In other words, the drive current Iout is proportional to the magnitude of the operating current Iop.

[0083] As shown in FIG. 15, each oscillation prevention circuit 33 includes an NMOS-FET 331, a first PMOS-FET 332, a second PMOS-FET 333, and an oscillation prevention switch unit 334. The anode of each iPM laser 2 is connected to the source terminal of the NMOS-FET 331. The source terminal of the NMOS-FET 331 is also connected to the gate terminal of the first PMOS-FET 332. The source terminal of the first PMOS-FET 332 is connected to the drain terminal of the second PMOS-FET 333. The second PMOS-FET 333 supplies a current to the first PMOS-FET 332 in response to an input voltage to the gate terminal of the second PMOS-FET 333. The potential between the first PMOS-FET 332 and the second PMOS-FET 333 is supplied to the gate terminal of the NMOS-FET 331. The first PMOS-FET 332 and the second PMOS-FET 333 form a feedback circuit. The drain terminal of the NMOS-FET 331 is connected to the voltage source 325 (first constant potential line). The drain terminal of the first PMOS-FET 332 is connected to the reference potential line GND (second constant potential line). The source terminal of the second PMOS-FET 333 is connected to the voltage source 325 (third constant potential line). The oscillation prevention switch unit 334 is connected between the anode of each iPM laser 2 and the source terminal of the NMOS-FET 331. The oscillation prevention switch unit 334 includes a first oscillation prevention switch 334a and a second oscillation prevention switch 334b. The first oscillation prevention switch 334a and the second oscillation prevention switch 334b ​​are connected in series with each other. The first oscillation prevention switch 334a is electrically connected to the first shift register 34a (see FIG. 14). The first oscillation prevention switch 334a is switched on / off in response to an instruction signal S2 from the first shift register 34a. In other words, the operation of the first oscillation prevention switch 334a is completely synchronized with the operation of the first switch 322a. The second oscillation prevention switch 334b ​​is electrically connected to the second shift register 34b (see FIG. 14). The second oscillation prevention switch 334b ​​is turned on / off in response to an instruction signal S3 from the second shift register 34b. In other words, the operation of the second oscillation prevention switch 334b ​​is completely synchronized with the operation of the second switch 322b.

[0084] Each iPM laser 2 and the drain terminal of the PMOS-FET 321b are connected by a wiring 335 having inductance. The first switch 322a, the second switch 322b, and the plurality of third switches 314a to 314d are switched by an external control circuit 4 at a cycle of, for example, several kHz to several GHz. Therefore, when each switch is turned on / off, peaking or ringing may occur due to a resonance phenomenon associated with the inductance of the wiring 335.

[0085] In each oscillation prevention circuit 33, the impedance of the NMOS-FET 331 has the effect of lowering the resonance constant Q due to the effect of a feedback loop. That is, the denominator of the resonance constant Q includes the impedance component of the NMOS-FET 331, thereby reducing the resonance constant Q. In this way, each oscillation prevention circuit 33 can reduce the resonance constant Q, thereby suppressing ringing and peaking in the path through which the drive current Iout flows. This prevents overcurrent and current overshoot from occurring in each iPM laser 2, enabling stable operation of the iPM laser 2. Furthermore, because the operation of the first oscillation prevention switch 334a is perfectly synchronized with the operation of the first switch 322a and the operation of the second oscillation prevention switch 334b ​​is perfectly synchronized with the operation of the second switch 322b, a drain current can flow through the NMOS-FET 331 at the timing when the operating current Iop is supplied to each current mirror circuit 32. This reduces heat generation compared to when a drain current is always flowing through the NMOS-FET 331.

[0086] FIG. 17 is a diagram illustrating the configuration of the switch operation unit 34 shown in FIG. 14. For ease of explanation, it is assumed that multiple current mirror circuits 32 are arranged in a matrix with the X-axis and Y-axis directions as row and column directions. Each current mirror circuit 32 is connected to a respective iPM laser 2, but the multiple iPM lasers 2 are not illustrated in FIG. 17. The first shift register 34a has parallel outputs. In the example of FIG. 17, the first shift register 34a has a four-terminal output consisting of output terminals 34a1 to 34a4, each connected to a respective column of the multiple current mirror circuits 32. The first shift register 34a drives each column of the multiple current mirror circuits 32 in response to an instruction signal S2 from the external control circuit 4. Similarly, in the example of FIG. 17, the second shift register 34b has a four-terminal output consisting of output terminals 34b1 to 34b4, each connected to a respective row of the multiple current mirror circuits 32. The second shift register 34b drives each row of the plurality of current mirror circuits 32 in response to an instruction signal S3 from the external control circuit 4. [Measurement method using a three-dimensional measuring device]

[0087] FIG. 18 is a schematic diagram showing the configuration of a three-dimensional measuring apparatus 10. As shown in FIG. 18, the three-dimensional measuring apparatus 10 includes a semiconductor light-emitting device 1 equipped with multiple iPM lasers 2, a standalone imaging unit 50, and a measuring unit 60. Light L1 emitted from the multiple iPM lasers 2 is irradiated onto a certain area on the surface of a measurement object SA placed on a stage 7. The stage 7 may be a scanning stage capable of scanning in two or three dimensions. Note that if the irradiation range of light L1 is sufficiently wide compared to the measurement range of the measurement object SA, the stage 7 may be omitted.

[0088] The imaging unit 50 is a device that is sensitive to the light L1 emitted from the multiple iPM lasers 2. For example, a CCD (Charge Coupled Device) camera, a CMOS (Complementary MOS) camera, or other two-dimensional image sensors can be used as the imaging unit 50. The imaging unit 50 images the measurement object SA in a state where it is irradiated with the light L1, and outputs an output signal indicating the imaging result to the measurement unit 60.

[0089] The measurement unit 60 is a computer system including, for example, a processor, a memory, etc. The measurement unit 60 executes various control functions using a processor. Examples of computer systems include a personal computer, a microcomputer, a cloud server, and a smart device (such as a smartphone or tablet terminal). The measurement unit 60 may be configured by a programmable logic controller (PLC) or an integrated circuit such as a field-programmable gate array (FPGA).

[0090] The light L1 forms, for example, a sinusoidal stripe pattern W1 as shown in FIG. 19. In FIG. 19, the light intensity in the stripe pattern W1 is represented by the shade of color, with darker (closer to black) parts having higher light intensity and lighter (closer to white) parts having lower light intensity. The stripe pattern W1 is a periodic stripe pattern shown, for example, in an image area of ​​100 x 100 pixels. The period of the stripe pattern W1 is, for example, 20 pixels. The brightness of the stripe pattern W1 changes depending on the intensity of the light L1. The bright parts (black parts) of the stripe pattern W1 are parts where the intensity of the light L1 is high, and the dark parts (white parts) of the stripe pattern W1 are parts where the intensity of the light L1 is low.

[0091] The stripe pattern W1 is formed by combining multiple stripe elements formed by light output from multiple iPM lasers 2. For simplicity, we will use an example in which four iPM lasers 2 are used to form a stripe pattern W1 with a four-pixel period. Figure 20(a) shows a first stripe element Wa formed by light output from a certain iPM laser 2 (hereinafter referred to as the first iPM laser). Only the pattern output from the first iPM laser is shown in Figure 20(a). The patterned portion is indicated by halftone dots, and the higher the halftone dot density, the higher the light intensity. Figure 20(b) shows a second stripe element Wb formed by light output from another iPM laser 2 (hereinafter referred to as the second iPM laser). Only the pattern output from the second iPM laser is shown in Figure 21(a). Figure 21(a) shows a third stripe element Wc formed by light output from yet another iPM laser 2 (hereinafter referred to as the third iPM laser). FIG. 21(a) shows only the pattern output by the third iPM laser. FIG. 21(b) shows the fourth stripe element Wd formed by the light output by yet another iPM laser 2 (hereinafter referred to as the fourth iPM laser). FIG. 21(b) shows only the pattern output by the fourth iPM laser. The light output by these iPM lasers 2 is included in the light L1. Comparing FIG. 20(a) with FIG. 20(b), the phase of the second stripe element Wb is shifted by π / 2 (rad), or 1 / 4 period, from the phase of the first stripe element Wa. Also, in this example, the light intensity of the second stripe element Wb is greater than the light intensity of the first stripe element Wa. Comparing FIG. 20(b) with FIG. 21(a), the phase of the third stripe element Wc is shifted by π / 2 (rad), or 1 / 4 period, from the phase of the second stripe element Wb. In this example, the light intensity of the third stripe element Wc is smaller than the light intensity of the second stripe element Wb. Comparing Figures 21(a) and 21(b), the phase of the fourth stripe element Wd is shifted by π / 2, or ¼ period, from the phase of the third stripe element Wc.In this example, the light intensity of the fourth stripe element Wd is smaller than the light intensity of the third stripe element Wc. FIG. 22 is a graph showing the light intensity distribution of the stripe pattern W1 generated by combining the first to fourth stripe elements Wa to Wd. In FIG. 22, the horizontal axis represents the position (in other words, the phase of the stripe pattern W1) in the direction intersecting the stripes (the periodic direction of the sine wave), and the vertical axis represents the light intensity. As shown in FIG. 22, in the stripe pattern W1, a pattern having a sinusoidal light intensity distribution is realized by appropriately adjusting the light intensities of the first to fourth stripe elements Wa to Wd. The more iPM lasers 2 there are (the more stripe elements there are), the closer the pattern approaches an accurate sine wave. Note that FIG. 22 shows two sine waves included in the stripe pattern W1.

[0092] When generating a stripe pattern W1 with a period of 4 pixels, both the first switch 322a and the second switch 322b of each current mirror circuit 32 connected to the first to fourth iPM lasers are turned on in the order of the first iPM laser, the second iPM laser, the third iPM laser, and the fourth iPM laser during one frame exposure period of the imaging unit 50. Furthermore, in synchronization with the switching timing of the first switch 322a and the second switch 322b, the multiple third switches 314a to 314d of the current source circuit 31 are switched in any order. In other words, the first to fourth iPM lasers are driven individually in order, and at the same time, the value of the drive current Iout supplied to each is increased or decreased. As a result, the first stripe element Wa, the second stripe element Wb, the third stripe element Wc, and the fourth stripe element Wd output from the first iPM laser, the second iPM laser, the third iPM laser, and the fourth iPM laser, respectively, are synthesized in the imaging of one frame by the imaging unit 50, and are recognized as a stripe pattern W1 in the imaging unit 50.

[0093] The measurement unit 60 measures the three-dimensional shape of the measurement object SA based on a phase shift method using a stripe pattern W1. In this embodiment, for example, a plurality of sinusoidal stripe patterns W1 are used, each of which is given a phase shift (positional deviation) that is an equal division of one period of the grating pitch. The phase shift patterns may be prepared with a phase shift of 2π / N (N is an integer).

[0094] Here, we will explain the case where four sinusoidal stripe patterns W1 with different phase shifts are used. If the light intensities of the four lights L1 having the four sinusoidal stripe patterns W1 are I0 to I3, respectively, and the pixels of the imaging unit 50 are (x, y), the light intensities I0 to I3 on ​​the surface of the measurement object SA are expressed 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.

number

number

number

number

[0095] The initial phase θ can be calculated by tan θ=-(I3-I1) / (I2-I0). When the number of phase shifts of the sinusoidal stripe pattern W1 is N, the initial phase θ can be calculated by the following formula (34).

number

[0096] When using this phase shift method, the measured phase is converted into height, allowing the height of the object SA to be measured at intervals smaller than the pitch of the sinusoidal stripe pattern W1. In configuring the three-dimensional measuring device 10, multiple iPM lasers 2 may be arranged in a direction parallel to the stripes in the sinusoidal stripe pattern W1. In this case, it is possible to eliminate phase shifts caused by misalignment of the multiple iPM lasers 2, thereby eliminating the initial phase shift in each of the multiple sinusoidal stripe patterns W1.

[0097] Here, we will explain the use of four sinusoidal stripe patterns with mutually different phases. Figure 23(a) shows the first stripe pattern W11, Figure 23(b) shows the second stripe pattern W12, Figure 24(a) shows the third stripe pattern W13, and Figure 24(b) shows the fourth stripe pattern W14. As shown in Figure 23(a), the first stripe pattern W11 is a sinusoidal stripe pattern in which the light intensity of the first stripe element Wa is the highest and the light intensity of the third stripe element Wc is the lowest. Next, as shown in Figure 23(b), the second stripe pattern W12 is a sinusoidal stripe pattern in which the light intensity of the second stripe element Wb is the highest and the light intensity of the fourth stripe element Wd is the lowest. In other words, a phase shift occurs from the first stripe pattern W11 to the second stripe pattern W12, in which the light intensity peak moves in the direction of phase advance. Next, as shown in FIG. 24(a), in the third stripe pattern W13, the light intensity of the third stripe element Wc is approximately equal to the light intensity of the second stripe element Wb. The light intensity of the fourth stripe element Wd is greater than the light intensity of the fourth stripe element Wd in the second stripe pattern W12. In other words, a phase shift occurs from the second stripe pattern W12 to the third stripe pattern W13. Next, as shown in FIG. 24(b), the fourth stripe pattern W14 is a sinusoidal stripe pattern in which the light intensity of the third stripe element Wc is greatest and the light intensity of the first stripe element Wa is least. In other words, a phase shift occurs from the third stripe pattern W13 to the fourth stripe pattern W14. As described above, a continuous phase shift is applied from the first stripe pattern W11 to the fourth stripe pattern W14. This allows the three-dimensional shape of the measurement object SA to be measured. Here, four sinusoidal stripe patterns are shown as an example of phase shift, but when measuring using the phase shift method, equally spaced phase shifts are preferable. [Action and effect]

[0098] In the semiconductor light-emitting device 1, the switch operating unit 34 individually operates each of the multiple switch units 322, thereby supplying a drive current Iout to each iPM laser 2 corresponding to the multiple switch units 322. If multiple current source circuits 31 corresponding to each iPM laser 2 were provided, even the current source circuits 31 corresponding to the inactive iPM lasers 2 would consume power (standby power) because they themselves are operating. In the semiconductor light-emitting device 1, the drive current Iout is supplied based on the operating current Iop generated by the common current source circuit 31, thereby reducing the amount of heat generated by standby power and achieving low power consumption. Furthermore, because the common current source circuit 31 is used, fewer current source circuits 31 are required, allowing the semiconductor light-emitting device 1 to be made smaller.

[0099] In the semiconductor light-emitting device 1, each of the multiple switch units 322 includes a first switch 322a and a second switch 322b connected in series with the first switch 322a, and the switch operating unit 34 includes a first shift register 34a that operates the first switch 322a and a second shift register 34b that operates the second switch 322b. This allows the drive current Iout to be supplied individually to only the iPM lasers 2 for which both the first switch 322a and the second switch 322b are turned on. The first shift register 34a can specify the iPM lasers 2 to be driven, for example, by row, and the second shift register 34b can specify the iPM lasers 2 to be driven, for example, by column. This facilitates the supply of the drive current Iout individually to multiple iPM lasers 2 arranged across multiple rows and columns.

[0100] In the semiconductor light-emitting device 1, the drive circuit 3 further includes a plurality of current mirror circuits 32 corresponding to the plurality of iPM lasers 2, and each of the plurality of current mirror circuits 32 includes a first current path 323 and a second current path 324 through which a current flows whose magnitude is proportional to the magnitude of the current flowing through the first current path 323. The first current path 323 is connected to a common current source circuit 31, the switch unit 322 is provided on the first current path 323, and the second current path 324 is connected to an iPM laser 2 among the plurality of iPM lasers 2 that corresponds to the current mirror circuit 32. This allows a drive current Iout based on an operating current Iop generated by the common current source circuit 31 to be supplied to the iPM laser 2 via the second current path 324.

[0101] In the semiconductor light-emitting device 1, the drive circuit 3 further includes a plurality of oscillation prevention circuits 33 corresponding to the plurality of iPM lasers 2, respectively. Each of the plurality of oscillation prevention circuits 33 includes an NMOS-FET 331 including a source terminal connected to the anode terminal of each of the plurality of iPM lasers 2 and a drain terminal connected to a voltage source 325, a first PMOS-FET 332 including a gate terminal connected to the source terminal of the NMOS-FET 331 and a drain terminal connected to a reference potential line GND having a lower potential than the voltage source 325, and a second PMOS-FET 333 including a drain terminal connected to the source terminal of the first PMOS-FET 332, a source terminal connected to a voltage source 325 having a higher potential than the reference potential line GND, and a gate terminal, and supplies a current to the first PMOS-FET 332 in accordance with an input voltage to the gate terminal. The potential between the first PMOS-FET 332 and the second PMOS-FET 333 is supplied to the gate terminal of the NMOS-FET 331. According to this, the resonance constant (Q value) can be reduced by providing the oscillation prevention circuit 33. As a result, ringing and peaking are suppressed, and the iPM laser 2 can be driven stably.

[0102] In the semiconductor light-emitting device 1, the value of the operating current Iop generated by the common current source circuit 31 is variable. This makes it possible to vary the magnitude of the drive current Iout, change the light intensity of each iPM laser 2, and consequently change the brightness of the optical image output from the multiple iPM lasers 2.

[0103] In the semiconductor light-emitting device 1, the common current source circuit 31 further includes an operational amplifier 311 having a pair of input terminals to which an input voltage Vop is supplied, an NMOS-FET 312 having a control terminal connected to the output terminal of the operational amplifier 311, and a resistor Rop having one end connected to the current terminal of the NMOS-FET 312 and the other input terminal of the operational amplifier 311 and the other end connected to a reference potential line GND. The resistance value of the resistor Rop is variable, and the switching operations of the multiple switch units 322 are synchronized with the operation of changing the resistance value of the resistor Rop. Thus, the variable resistance value of the resistor Rop changes the value of the operating current Iop generated by the current source circuit 31. Furthermore, the synchronization of the switching operations of the multiple switch units 322 with the operation of changing the resistance value of the resistor Rop allows the value of the drive current Iout supplied to each iPM laser 2 to be set for each iPM laser 2.

[0104] In the semiconductor light emitting device 1, the resistor section Rop includes a plurality of partial circuits 316a-316d connected in parallel between one end and the other end of the resistor section Rop, and each of the plurality of partial circuits 316a-316d includes resistors Rop1-Rop4 and third switches 314a-314d connected in series between one end and the other end of the resistor section Rop, and the switching operation of the plurality of switch sections 322 is synchronized with the switching operation of the third switches 314a-314d. This makes it possible to vary the resistance value of the resistor section Rop, and to synchronize the switching operation of the plurality of switch sections 322 with the operation of changing the resistance value of the resistor section Rop.

[0105] In the semiconductor light-emitting device 1, each of the multiple iPM lasers 2 has an active layer 22 as a light-emitting portion, a phase modulation layer 25A optically coupled to the active layer 22, a first clad layer 21 located on the first surface 2a side of the active layer 22 and the phase modulation layer 25A, a second clad layer 23 located on the second surface 2b side of the active layer 22 and the phase modulation layer 25A, a second electrode 26 located on the second surface 2b side of the second clad layer 23, and a first electrode 27 located on the first surface 2a side of the first clad layer 21, and the phase modulation layer 25A is provided in the basic layer 25a so as to be two-dimensionally distributed on a plane perpendicular to the normal direction of the first surface 2a, and has a refractive index different from that of the basic layer 25a. and a plurality of modified refractive index areas 25b having the following structure: in a state where a virtual square lattice is set on the surface, the plurality of modified refractive index areas 25b are arranged such that the center of gravity G of each of the plurality of modified refractive index areas 25b is a distance r(x, y) (a predetermined distance) from the corresponding lattice point, and the angles φ(x, y) around each lattice point in the virtual square lattice, that is, the angles φ(x, y) of the line segments connecting the center of gravity G of each of the plurality of modified refractive index areas 25b to the corresponding lattice point, with respect to the virtual square lattice are set according to a phase distribution for forming an optical image, and at least two of the angles φ(x, y) in the plurality of modified refractive index areas 25b are different from each other. This makes it possible to suitably realize the iPM laser 2.

[0106] In the semiconductor light-emitting device 1, the phase modulation layer 25B according to the modified example includes a base layer 25a and a plurality of modified refractive index regions 25b, which are two-dimensionally distributed within the base layer 25a on a plane perpendicular to the normal direction of the first surface 2a and have a refractive index different from that of the base layer 25a. When a virtual square lattice is set on the surface, the plurality of modified refractive index regions 25b are arranged such that the center of gravity G of each of the plurality of modified refractive index regions 25b is located on a straight line D that passes through a corresponding lattice point and is inclined to the virtual square lattice. The distance r(x, y) along the straight line D between the center of gravity G of each of the plurality of modified refractive index regions 25b and the corresponding lattice point is set according to the phase distribution for forming an optical image. The inclination angle θ of the straight line D is uniform throughout the plurality of modified refractive index regions 25b. This configuration effectively realizes an iPM laser.

[0107] In the semiconductor light-emitting device 1, the drive circuit 3 is connected to the multiple iPM lasers 2 by bump bonding. This allows the drive circuit 3 and the multiple iPM lasers 2 to be integrated, thereby further reducing the size of the device.

[0108] In the semiconductor light emitting device 1, each of the plurality of iPM lasers 2 is formed monolithically. This allows the plurality of iPM lasers 2 to be formed within a single element, making it possible to facilitate assembly of the semiconductor light emitting device 1. [Variations]

[0109] The present invention is not limited to the above-described embodiments. FIG. 25(a) is a diagram showing a portion of a drive circuit 3A according to a first modified example. Hereinafter, only the differences between the drive circuit 3A and the drive circuit 3 according to the embodiment will be described. The drive circuit 3A includes a current source circuit 31A, a digital-to-analog converter 317, and a serial-to-parallel converter 318. In the current source circuit 31A, the source terminal of the NMOS-FET 312 is connected to a resistor Rop. One end of the resistor Rop is connected to the source terminal of the NMOS-FET 312 and the inverting input terminal of the operational amplifier 311, and the other end of the resistor Rop is connected to the reference potential line GND. The non-inverting input terminal of the operational amplifier 311 is connected to a digital-to-analog converter 317, which is further connected to a serial-to-parallel converter 318. In the current source circuit 31A, the resistance value of the resistor Rop may be variable, as in the above-described embodiment, or may be fixed.

[0110] The serial-parallel converter 318 receives a serial signal S4 from an external control circuit provided outside the semiconductor light-emitting device 1. The serial signal S4 includes an instruction signal S2 for the first shift register 34a, an instruction signal S3 for the second shift register 34b, and an instruction signal S5 for setting the input voltage Vop. In other words, the instruction signal S5 is a signal indicating an instruction value for the amount of current for the common current source circuit 31. The instruction signals S2 and S3 are, for example, digital data in 4-bit binary notation, and the instruction signal S5 is, for example, digital data in 8-bit to 12-bit binary notation. In this case, the serial signal S4 includes 16-bit to 20-bit digital data. The number of wires between the external control circuit and the serial-parallel converter 318 is, for example, approximately three. In addition to the wires used to transmit the serial signal S4, wires for transmitting, for example, a clock signal and a synchronization signal are required. The serial-parallel converter 318 converts the serial signal S4 into a parallel signal S6 including the instruction signals S2, S3, and S5. The serial-to-parallel converter 316 outputs the instruction signal S2 of the parallel signal S6 to the first shift register 34a, and outputs the instruction signal S3 of the parallel signal S6 to the second shift register 34b.

[0111] The serial-parallel converter 318 outputs an instruction signal S5 from the parallel signal S6 to the digital-analog converter 317. The number of wires between the serial-parallel converter 318 and the digital-analog converter 317 is determined according to the number of bits of the instruction signal S5, and is, for example, 8 to 12. The digital-analog converter 317 converts the instruction signal S5 from digital data into an analog signal, i.e., an input voltage Vop, and outputs the input voltage Vop to the non-inverting input terminal of the operational amplifier 311. The current source circuit 31A generates an operating current Iop having a magnitude corresponding to the instruction signal S5 based on the input voltage Vop. The current source circuit 31A changes the instruction signal S5 in synchronization with the switching timing of the first switch 322a and the second switch 322b. In other words, the switching operation of the first switch 322a and the second switch 322b is synchronized with the operation of switching the value of the input voltage Vop. As a result, the value of the drive current Iout is set for each iPM laser 2.

[0112] As described above, the drive circuit 3A of the first modification includes a serial-to-parallel converter 318 for converting a serial signal S4 containing digital data representing a current instruction value for the current source circuit 31A into a parallel signal S6, and a digital-to-analog converter 317 for converting the digital data converted into the parallel signal S6 into an analog signal. The current source circuit 31A generates an operating current Iop having a magnitude corresponding to the instruction value based on the analog signal (input voltage Vop). This allows digital data representing a current instruction value for the current source circuit 31A to be received from an external control circuit as a serial signal S4, thereby reducing the number of wiring lines connecting the semiconductor light-emitting device 1 and the external control circuit and making the wiring lines thinner, thereby improving workability, for example, in three-dimensional measurement.

[0113] FIG. 25(b) is a diagram showing a current source circuit 31B according to a second modification. Hereinafter, only the differences between the current source circuit 31B and the current source circuit 31 of the above embodiment will be described. The current source circuit 31B does not have the voltage source 313 shown in FIG. 15. Instead, an input voltage Vop is supplied to the non-inverting input terminal of the operational amplifier 311 from an external control circuit provided outside the semiconductor light-emitting device 1. In the current source circuit 31B, similar to the current source circuit 31A, the magnitude of the input voltage Vop is changed in synchronization with the switching timing of the first switch 322a and the second switch 322b. This allows the value of the drive current Iout to be set for each iPM laser 2. In the current source circuit 31B, the resistance value of the resistor Rop may be variable, as in the above embodiment, or may be fixed. According to the second modification, the input voltage Vop, which is an analog signal representing the current instruction value for the current source circuit 31A, is input from an external control circuit. This reduces the number of wires connecting the semiconductor light emitting device 1 and the external control circuit, making the wires thinner, thereby improving workability in, for example, three-dimensional measurement.

[0114] FIG. 26 is a side view of a semiconductor light-emitting device 1A according to a third modification. As shown in FIG. 26, the semiconductor light-emitting device 1A includes a support substrate 6. The support substrate 6 has a third surface 6a and a fourth surface 6b opposite the third surface 6a. The iPM lasers 2 are not monolithically structured as in the above embodiment, but are individual chips. Each chip is individually mounted on the third surface 6a with its second surface 2b facing the third surface 6a. Adjacent iPM lasers 2 may be mounted at regular intervals or may be closely spaced. In the example shown in FIG. 26, the iPM lasers 2 and the drive circuits 3 are mounted on a common support substrate 6. Specifically, the iPM lasers 2 and the drive circuits 3 are arranged horizontally along the X-axis direction on the third surface 6a. The support substrate 6 includes wiring therein, and multiple electrodes 6c are formed along the third surface 6a. Each iPM laser 2, each current mirror circuit 32, and switch operation unit 34 are electrically connected to electrode 6c. That is, the electrical connection between the multiple iPM lasers 2 and the drive circuit 3 is made via wiring on the support substrate 6, rather than by direct bump bonding as in the above embodiment. The drive circuit 3 may be disposed on the fourth surface 6b of the support substrate 6. That is, the multiple iPM lasers 2 and the drive circuit 3 may be disposed on opposite sides of the support substrate 6. According to the configuration of the third modification, the multiple iPM lasers 2 can be formed discretely on the support substrate 6, and the multiple iPM lasers 2 formed discretely on the support substrate 6 can be integrated with the drive circuit 3, thereby achieving a compact device, as in the above embodiment.

[0115] 27 is a side view of a semiconductor light-emitting device 1B according to a fourth modification. In this example, similar to the above embodiment, the multiple iPM lasers 2 are monolithically formed. The drive circuit 3 and the multiple monolithically formed iPM lasers 2 are mounted on a common support substrate 6. With this configuration, the drive circuit 3 and the multiple monolithically formed iPM lasers 2 can be integrated on the common support substrate 6, and similar to the above embodiment, the device can be made smaller.

[0116] FIG. 28 is a partial cross-sectional view of a semiconductor light-emitting device 1K according to a fifth modification. In the semiconductor light-emitting device 1K, a semiconductor region 2d and multiple iPM lasers 2 are formed on a semiconductor substrate 20. The periphery of the semiconductor region 2d and the periphery of each iPM laser 2 are covered with an insulating film 28. A wiring electrode 27b is formed from the upper surface of the semiconductor region 2d to the side surface of the semiconductor region 2d via the insulating film 28. The wiring electrode 27b further continues from the side surface of the semiconductor region 2d and contacts the surface of the semiconductor substrate 20. A second electrode 26 is formed on the second surface 2b of each iPM laser 2. The height in the Z-axis direction of the wiring electrode 27b formed on the upper surface of the semiconductor region 2d is the same as the height in the Z-axis direction of the second electrode 26. This allows both the N electrode (wiring electrode 27b) and the P electrode (second electrode 26) to be disposed on a common surface of the semiconductor substrate 20, making the device suitable for surface mounting. Furthermore, by using the wiring electrode 27b, the wire bond that would be required when the first electrode 27 is used is no longer necessary.

[0117] FIG. 29 is a partial cross-sectional view of a semiconductor light-emitting device 1L according to a sixth modification. Only differences from the semiconductor light-emitting device 1K will be described. The side surfaces of each iPM laser 2 are covered with a second electrode 26 via an insulating film 28. Furthermore, a second electrode 26 is formed on the second surface 2b side of each iPM laser 2. In other words, each iPM laser 2 is shielded by the second electrode 26 along its entire periphery. This prevents laser light generated by each iPM laser 2 from interfering with adjacent iPM lasers 2, disrupting the laser mode, and achieving stable laser oscillation. When laser light interference is actively utilized, it is preferable not to shield the periphery of each iPM laser 2 with an electrode, as in the semiconductor light-emitting device 1K. (Second embodiment)

[0118] FIG. 30 is an exploded perspective view showing the configuration of a light source device 1C according to a second embodiment of the present disclosure. The three-dimensional measurement device 10 shown in FIG. 30 may include the light source device 1C of this embodiment instead of the semiconductor light-emitting device 1. That is, the light source device 1C of this embodiment is used for three-dimensional shape measurement using a phase-shift method. As shown in FIG. 30, the light source device 1C includes multiple iPM lasers 2 (first light sources), a drive circuit 3, a semiconductor substrate 20, a semiconductor region 2d, and a first electrode 27. In this embodiment, the multiple iPM lasers 2 are linearly arranged in a row with the Y-axis direction as the column direction. In the illustrated example, four iPM lasers are arranged along the Y-axis direction. As in the above embodiment, the multiple iPM lasers 2 are monolithically formed on the semiconductor substrate 20. The multiple iPM lasers 2 are arranged in a row in a direction intersecting the optical axis direction so that their optical axis directions (in other words, the thickness direction of each iPM laser 2) are aligned. In this embodiment, the optical axis direction of each iPM laser 2 coincides with the Z-axis direction, and the multiple iPM lasers 2 are arranged side by side in the Y-axis direction, which is perpendicular to the Z-axis direction. Note that the configurations of the other multiple iPM lasers 2, as well as the configurations of the drive circuit 3, semiconductor substrate 20, semiconductor region 2d, and first electrode 27 are similar to those of the semiconductor light-emitting device 1 of the previously described embodiment, and therefore detailed description thereof will be omitted.

[0119] 31(a), 31(b), 32(a), and 32(b) are diagrams schematically illustrating how light L1 including stripe elements Wa-Wd is projected from each of four iPM lasers 2 onto a common projection area. The stripe elements Wa-Wd are a first pattern in this embodiment. In each of the stripe elements Wa-Wd, multiple bright lines WL1 (shown by dots in the diagrams) are periodically arranged along a direction D1 (first direction) that intersects with the extension direction of the bright lines WL1. The spacing F between the multiple bright lines WL1 in the stripe elements Wa-Wd is equal among the stripe elements Wa-Wd (in other words, among the multiple iPM lasers 2). Furthermore, the positions of the multiple bright lines WL1 in direction D1, relative to the position of the optical axis of each iPM laser 2, differ among the multiple iPM lasers 2. In the examples shown in FIGS. 31 and 32, the bright lines WL1 of the stripe elements Wa to Wd are shifted from one another by π / 2 (rad), that is, 1 / 4 of a period. When the number of iPM lasers 2 is n, the shift amount of the bright lines WL1 between the multiple iPM lasers 2 is 1 / n of the interval (period) between the bright lines WL1. The multiple iPM lasers 2 are aligned along direction D2 (second direction) orthogonal to direction D1. That is, direction D2 coincides with the Y-axis direction shown in FIG. 30.

[0120] As shown in Figure 31(a), first, light L1 is projected from an iPM laser 2 (first iPM laser) located at one end in direction D2. This projects a stripe element Wa onto the common projection area. Next, as shown in Figure 31(b), light L1 is projected from an iPM laser 2 (second iPM laser) located next to the first iPM laser in direction D2. This projects a stripe element Wb onto the common projection area. At this time, a positional deviation E11 occurs in direction D2 between the stripe elements Wa and Wb output from these iPM lasers 2, depending on the arrangement pitch (optical axis spacing) of the first iPM laser and the second iPM laser. The magnitude of the positional deviation E11 is equal to the optical axis spacing between the first iPM laser and the second iPM laser. Meanwhile, the position of the bright line WL1 of the stripe element Wb in direction D1 is shifted by 1 / 4 period from the predetermined position, i.e., the bright line WL1 of the stripe element Wa, and no positional deviation occurs from the predetermined position. Next, as shown in FIG. 32(a), light L1 is projected from the iPM laser 2 (third iPM laser) located adjacent to the second iPM laser in the direction D2. As a result, a stripe element Wc is projected onto the common projection area. At this time, a positional shift E12 occurs between the stripe elements Wa and Wc in the direction D2 depending on the arrangement pitch (optical axis spacing) of the first to third iPM lasers. The magnitude of the positional shift E12 is equal to the sum of the optical axis spacings of the first to third iPM lasers. Meanwhile, the position of the bright line WL1 of the stripe element Wc in the direction D1 is shifted by 1 / 2 period from the predetermined position, i.e., the bright line WL1 of the stripe element Wa, and no positional shift occurs from the predetermined position. Next, as shown in FIG. 32(b), light L1 is projected from the iPM laser 2 (fourth iPM laser) located adjacent to the third iPM laser in the direction D2. As a result, a stripe element Wd is projected onto the common projection area. At this time, a positional deviation E13 occurs between the stripe elements Wa and Wd in the direction D2 according to the arrangement pitch (optical axis spacing) of the first to fourth iPM lasers. The magnitude of the positional deviation E13 is equal to the sum of the optical axis spacings of the first to fourth iPM lasers.On the other hand, the position of the bright line WL1 of the stripe element Wd in the direction D1 is a predetermined position, that is, a position shifted by 3 / 4 period from the bright line WL1 of the stripe element Wa, and no displacement from the predetermined position occurs.

[0121] Here, as a comparative example of this embodiment, a case where multiple iPM lasers 2 are lined up along direction D1 will be described. FIGS. 33(a), 33(b), 34(a), and 34(b) are schematic diagrams showing how light L1 including stripe elements Wa to Wd is projected from each of four iPM lasers 2 onto a common projection area in such a comparative example. As shown in FIG. 33(a), light L1 is first projected from an iPM laser 2 (first iPM laser) located at one end in direction D1. As a result, stripe element Wa is projected onto the common projection area. Next, as shown in FIG. 33(b), light L1 is projected from an iPM laser 2 (second iPM laser) located adjacent to the first iPM laser in direction D1. As a result, stripe element Wb is projected onto the common projection area. At this time, a misalignment E21 occurs in the direction D1 between the stripe elements Wa and Wb output from the first iPM laser 2 and the second iPM laser 2, depending on the arrangement pitch (optical axis spacing) between these iPM lasers. The magnitude of the misalignment E21 is equal to the optical axis spacing between the first iPM laser 2 and the second iPM laser. This misalignment E21 causes the bright line WL1 of the stripe element Wb to be misaligned from its predetermined position in the direction D1, i.e., a position shifted by ¼ period from the bright line WL1 of the stripe element Wa. Next, as shown in Figure 34(a), light L1 is projected from the iPM laser 2 (third iPM laser) positioned adjacent to the second iPM laser in the direction D1. As a result, the stripe element Wc is projected onto the common projection area. At this time, a misalignment E22 occurs in the direction D1 between the stripe elements Wa and Wc, depending on the arrangement pitch (optical axis spacing) between the first iPM laser 2 and the third iPM laser 2. The magnitude of the positional shift E22 is equal to the sum of the optical axis intervals of the first to third iPM lasers. This positional shift E22 causes the bright line WL1 of the stripe element Wc to be displaced from its predetermined position in the direction D1, i.e., a position shifted 1 / 2 period from the bright line WL1 of the stripe element Wa. Next, as shown in Figure 34(b), light L1 is projected from iPM laser 2 (fourth iPM laser) located next to the third iPM laser in the direction D1.As a result, the stripe element Wd is projected onto a common projection area. At this time, a positional deviation E23 occurs between the stripe elements Wa and Wd in the direction D1 according to the arrangement pitch (optical axis spacing) of the first to fourth iPM lasers. The magnitude of the positional deviation E23 is equal to the sum of the optical axis spacings of the first to fourth iPM lasers. This positional deviation E23 causes the bright line WL1 of the stripe element Wd to be displaced from its predetermined position in the direction D1, i.e., from a position shifted 3 / 4 period from the bright line WL1 of the stripe element Wa.

[0122] Figure 35 is a diagram illustrating the problem caused by the misalignment of the emission line WL1 in the comparative example. Figure 35 shows two adjacent iPM lasers 2 as a representative of multiple iPM lasers 2. The arrangement pitch of the two adjacent iPM lasers 2 is dy, the distance from the first surfaces 2a of these iPM lasers 2 to the projection surface H is Z1, and the deviation in the central angles of the stripe elements between the two adjacent iPM lasers 2 is dα. Using the arrangement pitch dy and the distance Z1, the deviation in the central angles dα can be geometrically expressed as in Equation (35) below.

number

[0123] To address the above problem, in this embodiment, when multiple iPM lasers 2 are aligned along direction D2 perpendicular to direction D1 (see FIGS. 33 and 34), the alignment direction of the multiple iPM lasers 2 is perpendicular to the alignment direction of the emission lines WL1 of the stripe elements Wa-Wd. Therefore, even if positional deviations E11-E13 occur between the multiple stripe elements Wa-Wd, these positional deviations E11-E13 do not affect the formation of the stripe pattern W1. Therefore, measurement errors in three-dimensional shape measurement can be reduced compared to the above comparative example.

[0124] Furthermore, in the light source device 1C of this embodiment, the spacing F between the bright lines WL1 of the stripe elements Wa-Wd is equal among the multiple iPM lasers 2, and the positions of the bright lines WL1 in the direction D1 based on the optical axis of each iPM laser 2 are different among the multiple iPM lasers 2. By projecting each of these stripe elements Wa-Wd from each of the multiple iPM lasers 2 onto a common projection area, three-dimensional shape measurement using the phase shift method can be suitably performed.

[0125] Furthermore, as in this embodiment, the light source device 1C may include a plurality of iPM lasers 2 as a plurality of first light sources. In this case, the light source that outputs light L1 including stripe elements Wa-Wd can be made smaller, and thus the light source device 1C can be made smaller. Note that the first light source is not limited to the iPM laser 2. The first light source may be another element (for example, an element combining a semiconductor laser and a diffraction grating element (DOE)) that can project light L1 including stripe elements Wa-Wd in which a plurality of emission lines WL1 are periodically arranged along the direction D1.

[0126] Furthermore, as in this embodiment, the plurality of iPM lasers 2 may be formed monolithically with respect to one another. In this case, the plurality of iPM lasers 2 are formed within a single element, which can facilitate the assembly of the light source device 1C.

[0127] Furthermore, as in this embodiment, the number of the multiple iPM lasers 2 may be n, and the shift amount of the bright lines WL1 between the multiple iPM lasers 2 may be 1 / n of the interval F between the bright lines WL1. In this case, the stripe pattern W1 shown in Fig. 19 is formed, and three-dimensional shape measurement by the phase shift method can be suitably performed.

[0128] FIGS. 37(a), 37(b), 38(a), and 38(b) are diagrams illustrating a modified example of the second embodiment, schematically illustrating how light L1, including stripe patterns W1a to W1d, is projected from four iPM lasers 2 onto a common projection area. The stripe patterns W1a to W1d are the first pattern in this modified example. In these figures, the light intensity of the stripe patterns W1a to W1d is indicated by a darker color, with higher light intensity indicated by a darker color and lower light intensity indicated by a lighter color. In each of the stripe patterns W1a to W1d, multiple emission lines WL2 are periodically arranged along a direction D1 intersecting the extension direction of the emission lines WL2. Each of the stripe patterns W1a to W1d preferably has a pattern in which the light intensity varies sinusoidally along the direction D1, as shown in FIG. 19, but it need not necessarily be sinusoidal, such as a top-hat pattern. That is, in this modification, three-dimensional shape measurement is performed using the phase shift method by projecting a stripe pattern from each iPM laser 2 onto the measurement object while shifting the phase of the stripe pattern of each iPM laser 2 for each iPM laser 2, and capturing an image for each projection of the stripe pattern from each iPM laser 2. Note that, except for the pattern output from the iPM laser 2, the configuration of the light source device is the same as in the second embodiment.

[0129] The spacing F2 between the multiple bright lines WL2 in the stripe patterns W1a-W1d, i.e., the period of the bright lines WL2, is equal among the stripe patterns W1a-W1d (in other words, among the multiple iPM lasers 2). Furthermore, the positions, i.e., the phases, of the multiple bright lines WL2 in direction D1, based on the position of the optical axis of each iPM laser 2, differ among the multiple iPM lasers 2. In the example shown in FIGS. 37 and 38, the bright lines WL2 in the stripe patterns W1a-W1d are shifted from one another by π / 2 (rad), i.e., ¼ period. When the number of iPM lasers 2 is n, the shift amount of the bright lines WL2 among the multiple iPM lasers 2 is 1 / n of the spacing (period) between the bright lines WL2. The phase modulation layer 25A or 25B of each iPM laser 2 has a phase distribution for outputting the stripe patterns W1a-W1d as described above. Similar to the second embodiment, the multiple iPM lasers 2 are aligned along direction D2, which is perpendicular to direction D1. That is, the direction D2 coincides with the Y-axis direction shown in FIG.

[0130] As shown in FIG. 37(a), first, light L1 is projected from an iPM laser 2 (first iPM laser) located at one end in direction D2. This projects a stripe pattern W1a onto the common projection area. Next, as shown in FIG. 37(b), light L1 is projected from an iPM laser 2 (second iPM laser) located next to the first iPM laser in direction D2. This projects a stripe pattern W1b onto the common projection area. At this time, a positional deviation E11 occurs in direction D2 between the stripe patterns W1a and W1b output from the first and second iPM lasers, depending on the arrangement pitch (optical axis spacing) of these iPM lasers. Meanwhile, the position of the bright line WL2 of the stripe pattern W1b in direction D1 is shifted by ¼ period from the bright line WL2 of the stripe pattern W1a, and no positional deviation occurs from the predetermined position. Next, as shown in FIG. 38(a), light L1 is projected from an iPM laser 2 (third iPM laser) positioned adjacent to the second iPM laser in direction D2. As a result, a stripe pattern W1c is projected onto the common projection area. At this time, a positional deviation E12 occurs between the stripe patterns W1a and W1c in direction D2 depending on the arrangement pitch (optical axis spacing) of the first to third iPM lasers. Meanwhile, the position of the bright line WL2 of the stripe pattern W1c in direction D1 is shifted by 1 / 2 period from the bright line WL2 of the stripe pattern W1a, and no positional deviation occurs from the predetermined position. Next, as shown in FIG. 38(b), light L1 is projected from an iPM laser 2 (fourth iPM laser) positioned adjacent to the third iPM laser in direction D2. As a result, a stripe pattern W1d is projected onto the common projection area. At this time, a positional deviation E13 occurs between the stripe patterns W1a and W1d in the direction D2 according to the arrangement pitch (optical axis spacing) of the first to fourth iPM lasers. On the other hand, the position of the bright line WL2 of the stripe pattern W1d in the direction D1 is shifted by 3 / 4 period from the predetermined position, that is, the bright line WL2 of the stripe pattern W1a, and no positional deviation occurs from the predetermined position.

[0131] Here, as a comparative example of this modification, a case where multiple iPM lasers 2 are lined up along direction D1 will be described. FIGS. 39(a), 39(b), 40(a), and 40(b) are schematic diagrams illustrating how light L1 including stripe patterns W1a to W1d is projected from each of four iPM lasers 2 onto a common projection area in such a comparative example. As shown in FIG. 39(a), light L1 is first projected from an iPM laser 2 (first iPM laser) located at one end in direction D1. As a result, stripe pattern W1a is projected onto the common projection area. Next, as shown in FIG. 39(b), light L1 is projected from an iPM laser 2 (second iPM laser) located adjacent to the first iPM laser in direction D1. As a result, stripe pattern W1b is projected onto the common projection area. At this time, a positional deviation E21 occurs in the direction D1 between the stripe patterns W1a and W1b output from the first iPM laser 2 and the second iPM laser 2, depending on the arrangement pitch (optical axis spacing) of these iPM lasers 2. This positional deviation E21 causes the bright line WL2 of the stripe pattern W1b to be displaced from its predetermined position in the direction D1, i.e., a position shifted by ¼ period from the bright line WL2 of the stripe pattern W1a. Next, as shown in FIG. 40(a), light L1 is projected from the iPM laser 2 (third iPM laser) positioned adjacent to the second iPM laser 2 in the direction D1. As a result, a stripe pattern W1c is projected onto the common projection area. At this time, a positional deviation E22 occurs in the direction D1 between the stripe patterns W1a and W1c, depending on the arrangement pitch (optical axis spacing) of the first iPM laser to the third iPM laser 2. This positional shift E22 causes the bright line WL2 of the stripe pattern W1c to be shifted from its predetermined position in the direction D1, i.e., a position shifted 1 / 2 period from the bright line WL2 of the stripe pattern W1a. Next, as shown in Figure 40(b), light L1 is projected from the iPM laser 2 (fourth iPM laser) located next to the third iPM laser in the direction D1. As a result, the stripe pattern W1d is projected onto the common projection area.At this time, a positional shift E23 occurs between the stripe patterns W1a and W1d in the direction D1 according to the arrangement pitch (optical axis spacing) of the first to fourth iPM lasers. This positional shift E23 causes the bright line WL2 of the stripe pattern W1d to be shifted from its predetermined position in the direction D1, i.e., from a position shifted 3 / 4 period from the bright line WL2 of the stripe pattern W1a. In the comparative example, the positional shift of the bright line WL2 reduces the phase shift accuracy of the stripe patterns W1b to W1d, resulting in a large measurement error.

[0132] To address the above problem, when multiple iPM lasers 2 are aligned along direction D2 perpendicular to direction D1 as in this modified example (see FIGS. 37 and 38), the alignment direction of the multiple iPM lasers 2 is perpendicular to the alignment direction of the emission lines WL2 of the stripe patterns W1a to W1d. Therefore, even if positional shifts E11 to E13 occur between the multiple stripe patterns W1a to W1d, the positional shifts E11 to E13 do not affect the phase shift accuracy of the stripe patterns W1b to W1d. Therefore, measurement errors in three-dimensional shape measurement can be reduced compared to the above comparative example.

[0133] Furthermore, in this modification, the intervals (periods) of the bright lines WL2 of the stripe patterns W1a to W1d are equal among the multiple iPM lasers 2, and the positions (phases) of the bright lines WL2 in the direction D1 based on the optical axis of each iPM laser 2 are different among the multiple iPM lasers 2. By projecting each of such stripe patterns W1a to W1d from each of the multiple iPM lasers 2 onto a common projection area, three-dimensional shape measurement using the phase shift method can be suitably performed.

[0134] FIGS. 41(a), 41(b), 42(a), and 42(b) are diagrams for explaining another modification of the second embodiment, and schematically show how light L1 including stripe patterns W2a to W2d is projected from each of four iPM lasers 2 onto a common projection area. The stripe patterns W2a to W2d are the first pattern in this modification. In these diagrams, the light intensity of the stripe patterns W2a to W2d is indicated by shading of color, with lower light intensity being indicated as lighter (white) and higher light intensity being indicated as darker (black). In each of the stripe patterns W2a to W2d, multiple bright lines WL3 are aligned along a direction D1 intersecting the extension direction of the bright lines WL3. Each of the stripe patterns W2a to W2d includes a Gray code pattern. In other words, the width and position of the bright lines WL3 represent the Gray code. In this modification, three-dimensional shape measurement is performed by projecting a stripe pattern from each iPM laser 2 onto an object to be measured while changing the Gray code included in the stripe pattern of each iPM laser 2 for each iPM laser 2, and capturing an image each time the stripe pattern is projected from each iPM laser 2. Note that, except for the pattern output from the iPM laser 2, the configuration of the light source device is the same as in the second embodiment.

[0135] Gray code is a method of representing binary numbers. Figure 43 is a diagram showing the interconversion between decimal numbers, binary code (another method of representing binary numbers), and Gray code. Gray code is characterized by the fact that only one bit changes when a number is increased or decreased by 1. Because only one bit changes, it is less likely to malfunction and is widely used in digital circuits. Figure 44 is a diagram showing an example of a stripe pattern combination including a 4-bit Gray code. The diagram shows the light and dark of each of multiple bits aligned along direction D1. Figure 44 shows, as an example, stripe patterns W2a to W2d including four different Gray codes. Conversion from binary code to Gray code follows the following rules: First, the most significant bit of the Gray code, 1, is assumed to be the same as the binary code. Subsequently, the two adjacent bits are referenced, starting from the most significant bit. If there are consecutive 1s or 0s, the corresponding bit in the Gray code is set to 0; if there are no consecutive 1s or 0s, the corresponding bit in the Gray code is set to 1. Alternatively, conversion from binary code to Gray code may follow the following rules: First, a target binary code is prepared. Then, the binary code is shifted one bit to the right to obtain a binary code with a leading 0. Then, the exclusive OR of the binary code and the original binary code is calculated. The result of this calculation is the Gray code. For example, OpenCV can be used to generate the Gray code.

[0136] In Gray code, the Hamming distance between adjacent bits is 1. Hamming distance refers to the number of different digits in corresponding positions when comparing two values ​​with the same number of digits. Therefore, in Gray code, which has a Hamming distance of 1, even if a bit error occurs when restoring the bit string, the error is contained to 1. In binary code, if an error occurs in the upper bit, the position error becomes large, but Gray code produces a code that is resistant to noise.

[0137] The stripe patterns W2a to W2d are configured with stripe patterns set to have different gray code values ​​from one another. The three-dimensional shape of the measurement object SA can be measured by capturing images with the imaging unit 50 while switching between these four stripe patterns W2a to W2d in order.

[0138] In order to avoid erroneous recognition due to the color of the surface of the object to be measured SA, a stripe pattern including another gray code in which each bit value of the gray code of the stripe patterns W2a to W2d shown in Fig. 44 is inverted may also be used. In this case, it is preferable to provide four more iPM lasers 2 for outputting a stripe pattern including another gray code.

[0139] Similar to the second embodiment, the multiple iPM lasers 2 are arranged along a direction D2 that is perpendicular to the direction D1. That is, the direction D2 coincides with the Y-axis direction shown in FIG.

[0140] Using stripe patterns W2a to W2d in FIG. 44 as an example, the operation of sequentially switching among four stripe patterns will be described. As shown in FIG. 41(a), first, light L1 is projected from an iPM laser 2 (first iPM laser) located at one end in direction D2. As a result, stripe pattern W2a is projected onto a common projection area. Next, as shown in FIG. 41(b), light L1 is projected from an iPM laser 2 (second iPM laser) located next to the first iPM laser in direction D2. As a result, stripe pattern W2b is projected onto a common projection area. At this time, a positional deviation E11 occurs in direction D2 between stripe patterns W2a and W2b output from these iPM lasers 2 depending on the arrangement pitch (optical axis spacing) of the first iPM laser and second iPM laser. On the other hand, the position of bright line WL3 of stripe pattern W2b does not deviate from its predetermined position in direction D1. Next, as shown in FIG. 42(a), light L1 is projected from an iPM laser 2 (third iPM laser) positioned adjacent to the second iPM laser in direction D2. As a result, a stripe pattern W2c is projected onto the common projection area. At this time, a positional deviation E12 occurs between the stripe patterns W2a and W2c in direction D2 depending on the arrangement pitch (optical axis spacing) of the first to third iPM lasers. On the other hand, the position of the bright line WL3 of the stripe pattern W2c does not deviate from its predetermined position in direction D1. Next, as shown in FIG. 42(b), light L1 is projected from an iPM laser 2 (fourth iPM laser) positioned adjacent to the third iPM laser in direction D2. As a result, a stripe pattern W2d is projected onto the common projection area. At this time, a positional deviation E13 occurs between the stripe patterns W2a and W2d in direction D2 depending on the arrangement pitch (optical axis spacing) of the first to fourth iPM lasers. On the other hand, the position of the bright line WL3 of the stripe pattern W2d in the direction D1 does not deviate from the predetermined position.

[0141] When multiple iPM lasers 2 are aligned along direction D2 perpendicular to direction D1 as in this modification (see FIGS. 41 and 42), the alignment direction of the multiple iPM lasers 2 is perpendicular to the alignment direction of the bright lines WL3 of the stripe patterns W2a to W2d. Therefore, even if positional shifts E11 to E13 occur between the multiple stripe patterns W2a to W2d, the positional shifts E11 to E13 do not affect the calculation of the three-dimensional shape. Therefore, measurement errors in three-dimensional shape measurement can be reduced. (Third embodiment)

[0142] 45 and 46 are perspective views showing the configurations of light source devices 1D and 1E according to a third embodiment of the present disclosure, respectively. Light source device 1D shown in FIG. 45 and light source device 1E shown in FIG. 46 include light source groups 201 and 202. Light source group 201 includes a plurality (four in the illustrated example) of iPM lasers 2A (first light sources) arranged side by side in a direction intersecting the optical axis direction so that their optical axes are aligned. Light source group 202 includes a plurality (four in the illustrated example) of iPM lasers 2B (second light sources) arranged side by side in a direction intersecting the optical axis direction so that their optical axes are aligned. The plurality of iPM lasers 2A and the plurality of iPM lasers 2B are monolithically formed on a common semiconductor substrate 20. The internal structures of iPM lasers 2A and 2B are similar to those of the iPM laser 2 according to the first embodiment described above.

[0143] Each of the multiple iPM lasers 2A projects light including the stripe elements Wa to Wd (see FIGS. 31 and 32) or the stripe patterns W1a to W1d (see FIGS. 37 and 38) onto a common projection area. The stripe elements Wa to Wd or the stripe patterns W1a to W1d projected from the multiple iPM lasers 2A are the first pattern in this embodiment. Each of the multiple iPM lasers 2B projects light including the stripe elements Wa to Wd or the stripe patterns W1a to W1d onto the common projection area. The stripe elements Wa to Wd or the stripe patterns W1a to W1d projected from the multiple iPM lasers 2B are the second pattern in this embodiment. Similar to the multiple iPM lasers 2 in the second embodiment or its modified example, the multiple iPM lasers 2A are aligned along a direction D12 (corresponding to the above-mentioned direction D2) perpendicular to the alignment direction D11 (corresponding to the above-mentioned direction D1) of the bright lines of the stripe elements Wa-Wd or the stripe patterns W1a-W1d. The multiple iPM lasers 2B are aligned along a direction D22 (fourth direction, corresponding to the above-mentioned direction D2) perpendicular to the alignment direction D21 (third direction, corresponding to the above-mentioned direction D1) of the bright lines of the stripe elements Wa-Wd or the stripe patterns W1a-W1d. In the illustrated example, the directions D21 and D22 coincide with the directions D11 and D12, respectively, but the directions D21 and D22 may differ from the directions D11 and D12.

[0144] The period of the stripe pattern W1 (see FIG. 19) formed by the stripe elements Wa-Wd output from the light source group 202 or the period of the stripe patterns W1a-W1d is different from the period of the stripe pattern W1 formed by the stripe elements Wa-Wd output from the light source group 201 or the period of the stripe patterns W1a-W1d. In the light source device 1D shown in FIG. 45, the light source group 201 and the light source group 202 are arranged side by side in a direction intersecting with the respective arrangement directions D12 and D22. In the light source device 1E shown in FIG. 46, the light source group 201 and the light source group 202 are arranged side by side along the respective arrangement directions D12 and D22.

[0145] The intervals (periods) of the bright lines of the stripe elements Wa-Wd or the stripe patterns W1a-W1d are equal among the multiple iPM lasers 2A. Furthermore, the positions (phases) of the bright lines in direction D11, based on the optical axis of each iPM laser 2A, differ among the multiple iPM lasers 2A. Similarly, the intervals (periods) of the bright lines of the stripe elements Wa-Wd or the stripe patterns W1a-W1d are equal among the multiple iPM lasers 2B. Furthermore, the positions (phases) of the bright lines in direction D21, based on the optical axis of each iPM laser 2B, differ among the multiple iPM lasers 2B. By projecting such stripe elements Wa-Wd or stripe patterns W1a-W1d onto a common projection area from the multiple iPM lasers 2A or 2B, three-dimensional shape measurement using the phase shift method can be suitably performed.

[0146] In the light source devices 1D and 1E of this embodiment, three-dimensional shape measurement using the phase shift method can be performed at least twice using two light source groups: a light source group 201 including multiple iPM lasers 2A and a light source group 202 including multiple iPM lasers 2B. Furthermore, in the light source devices 1D and 1E of this embodiment, the multiple iPM lasers 2A are aligned along a direction D12 perpendicular to the alignment direction D11 of the bright lines, and the multiple iPM lasers 2B are aligned along a direction D22 perpendicular to the alignment direction D21 of the bright lines. In this case, even if the positions of the iPM lasers 2A (or 2B) are shifted by the alignment pitch, the shift direction is perpendicular to the alignment direction of the bright lines. Therefore, even if the stripe elements Wa-Wd or the stripe patterns W1a-W1d of the multiple iPM lasers 2A (or 2B) are misaligned, the misalignment does not affect the phase shift accuracy, etc. Therefore, the light source devices 1D and 1E of this embodiment can reduce measurement errors in three-dimensional shape measurement using the phase shift method.

[0147] As in this embodiment, the spacing (period) of the bright lines of the stripe pattern W1 or the stripe patterns W1a to W1d formed by the stripe elements Wa to Wd output from the light source group 202 may be different from the spacing (period) of the bright lines of the stripe pattern W1 or the stripe patterns W1a to W1d formed by the stripe elements Wa to Wd output from the light source group 201. In this case, three-dimensional shape measurement using the phase shift method can be performed using two types of stripe patterns with different spacing between the bright lines, thereby further improving measurement accuracy. [Variations]

[0148] FIG. 47 is a perspective view showing the configuration of a light source device 1F according to a modification of the third embodiment. The light source device 1F shown in FIG. 47 further includes light source groups 203 and 204 in addition to the light source groups 201 and 202 of the third embodiment. The light source group 203 includes a plurality (four in the illustrated example) of iPM lasers 2C (second light sources) arranged side by side in a direction intersecting the optical axis direction so that their optical axis directions are aligned. The light source group 204 includes a plurality (four in the illustrated example) of iPM lasers 2D (second light sources) arranged side by side in a direction intersecting the optical axis direction so that their optical axis directions are aligned. The plurality of iPM lasers 2C and the plurality of iPM lasers 2D are monolithically formed on a common semiconductor substrate 20 together with the plurality of iPM lasers 2A and the plurality of iPM lasers 2B. The internal structures of the iPM lasers 2C and 2D are similar to those of the iPM laser 2 of the first embodiment described above.

[0149] Each of the multiple iPM lasers 2C projects light including the stripe elements Wa to Wd (see FIGS. 31 and 32) or the stripe patterns W1a to W1d (see FIGS. 37 and 38) onto a common projection area. The stripe elements Wa to Wd or the stripe patterns W1a to W1d projected from the multiple iPM lasers 2C are the second pattern in this modification. Each of the multiple iPM lasers 2D projects light including the stripe elements Wa to Wd or the stripe patterns W1a to W1d onto the common projection area. The stripe elements Wa to Wd or the stripe patterns W1a to W1d projected from the multiple iPM lasers 2D are also the second pattern in this modification. The multiple iPM lasers 2C are aligned along a direction D32 (a fourth direction, corresponding to the above-described direction D2) perpendicular to the arrangement direction D31 (a third direction, corresponding to the above-described direction D1) of the emission lines of the stripe elements Wa to Wd or the stripe patterns W1a to W1d. The multiple iPM lasers 2D are aligned along a direction D42 (fourth direction, corresponding to the above-mentioned direction D2) that is perpendicular to the alignment direction D41 (third direction, corresponding to the above-mentioned direction D1) of the bright lines of the stripe elements Wa-Wd or the stripe patterns W1a-W1d. In the illustrated example, the directions D41 and D42 are aligned with the directions D31 and D32, respectively, but the directions D41 and D42 may be different from the directions D31 and D32. In addition, the directions D31 and D41 intersect with the directions D11 and D21. In the illustrated example, the directions D31 and D41 are aligned perpendicular to the directions D11 and D21, but the directions D31 and D41 may be inclined with respect to the directions D11 and D21.

[0150] The period of stripe pattern W1 (see FIG. 19) formed by stripe elements Wa to Wd output from light source group 203 or the period of stripe patterns W1a to W1d is different from the period of stripe pattern W1 formed by stripe elements Wa to Wd output from light source group 204 or the period of stripe patterns W1a to W1d. In light source device 1F shown in FIG. 47, light source group 203 and light source group 204 are arranged side by side in a direction intersecting with their respective arrangement directions D32 and D42, but light source group 203 and light source group 204 may also be arranged side by side along their respective arrangement directions D32 and D42.

[0151] The intervals (periods) of the bright lines of the stripe elements Wa-Wd or the stripe patterns W1a-W1d are equal among the multiple iPM lasers 2C. Furthermore, the positions (phases) of the bright lines in direction D31, based on the optical axis of each iPM laser 2C, differ among the multiple iPM lasers 2C. Similarly, the intervals (periods) of the bright lines of the stripe elements Wa-Wd or the stripe patterns W1a-W1d are equal among the multiple iPM lasers 2D. Furthermore, the positions (phases) of the bright lines in direction D41, based on the optical axis of each iPM laser 2D, differ among the multiple iPM lasers 2D. By projecting such stripe elements Wa-Wd or stripe patterns W1a-W1d onto a common projection area from the multiple iPM lasers 2C or 2D, three-dimensional shape measurement using the phase shift method can be suitably performed.

[0152] In the light source device 1F of this modification, three-dimensional shape measurement using the phase shift method can be performed at least four times using four light source groups: a light source group 201 including multiple iPM lasers 2A, a light source group 202 including multiple iPM lasers 2B, a light source group 203 including multiple iPM lasers 2C, and a light source group 204 including multiple iPM lasers 2D, thereby improving measurement accuracy. Furthermore, in the light source device 1F of this modification, the multiple iPM lasers 2C are aligned along a direction D32 perpendicular to the alignment direction D31 of the bright lines, and the multiple iPM lasers 2D are aligned along a direction D42 perpendicular to the alignment direction D41 of the bright lines. In this case, even if the positions of the individual iPM lasers 2C (or 2D) are shifted by the arrangement pitch, the shift direction is perpendicular to the alignment direction of the bright lines. Therefore, even if the stripe elements Wa-Wd or the stripe patterns W1a-W1d are misaligned among the multiple iPM lasers 2C (or 2D), the misalignment does not affect the phase shift accuracy, etc. Therefore, the light source device 1F of this modified example can reduce measurement errors in three-dimensional shape measurement using the phase shift method.

[0153] As in this modification, the spacing (period) of the bright lines of the stripe pattern W1 or the stripe patterns W1a to W1d formed by the stripe elements Wa to Wd output from the light source group 204 may be different from the spacing (period) of the bright lines of the stripe pattern W1 or the stripe patterns W1a to W1d formed by the stripe elements Wa to Wd output from the light source group 203. In this case, three-dimensional shape measurement using the phase shift method can be performed using two types of stripe patterns with different spacing between the bright lines, thereby further improving measurement accuracy.

[0154] As in this modification, the arrangement direction D31 of the bright lines output from the multiple iPM lasers 2C and the arrangement direction D41 of the bright lines output from the multiple iPM lasers 2D may intersect with the arrangement direction D11 of the bright lines output from the multiple iPM lasers 2A and the arrangement direction D21 of the bright lines output from the multiple iPM lasers 2B. In this case, three-dimensional shape measurement using the phase shift method can be performed using two or more types of stripe patterns whose bright line arrangement directions are different from each other, thereby further improving measurement accuracy. (Fourth embodiment)

[0155] FIG. 48 is a perspective view showing the configuration of a light receiving and emitting module 1G according to a fourth embodiment of the present disclosure. The light receiving and emitting module 1G shown in FIG. 48 further includes an imaging element 51 in addition to the configuration of the light source device 1F shown in FIG. 47. The light receiving and emitting module 1G of this modification differs from the light source device 1F in that the light source groups 201 to 204 are arranged to surround the imaging element 51. Specifically, the light source groups 201 and 202 are arranged side by side in directions D11 and D21, with the imaging element 51 disposed therebetween. The light source groups 203 and 204 are arranged side by side in directions D31 and D41, with the imaging element 51 disposed therebetween. The configuration of each of the light source groups 201 to 204 is the same as that of the third embodiment and its modification.

[0156] The imaging element 51 is provided on a common substrate together with the iPM lasers 2A to 2D. In one example, the imaging element 51 is monolithically formed on the semiconductor substrate 20 together with the iPM lasers 2A to 2D. The imaging element 51 is provided in place of the imaging unit 50 shown in FIG. 18. The imaging element 51 is sensitive to the light L1 emitted from the iPM lasers 2A to 2D. The imaging element 51 captures an image of the stripe elements Wa to Wd or the stripe patterns W1a to W1d in the measurement object (projection area) irradiated with the light L1, generates image data indicative of the imaging results, and outputs the image data to the measurement unit 60 (see FIG. 18).

[0157] According to the light receiving and emitting module 1G of this embodiment, by including the configuration of the light source device 1D, it is possible to achieve the same effects as those of the light source device 1D. Moreover, according to the light receiving and emitting module 1G of this embodiment, by including the configuration of the light source device 1F, it is possible to achieve the same effects as those of the light source device 1F. [Variations]

[0158] 49 is a perspective view showing the configuration of a light receiving and emitting module 1H according to a modification of the fourth embodiment. This modification differs from the fourth embodiment in that the number of iPM lasers included in the light source groups 201-204 is three, and one of the multiple iPM lasers included in each of the light source groups 201-204 is included in the arrangement of another adjacent light source group.

[0159] Specifically, one iPM laser 2A located at a first end in the arrangement direction among the three iPM lasers 2A constituting the light source group 201 is located on the second end side of the three iPM lasers 2D constituting the light source group 204, and is aligned in a row with these iPM lasers 2D. Similarly, one iPM laser 2D located at a first end in the arrangement direction among the three iPM lasers 2D constituting the light source group 204 is located on the second end side of the three iPM lasers 2B constituting the light source group 202, and is aligned in a row with these iPM lasers 2B. One iPM laser 2B located at a first end in the arrangement direction among the three iPM lasers 2B constituting the light source group 202 is located on the second end side of the three iPM lasers 2C constituting the light source group 203, and is aligned in a row with these iPM lasers 2C. Of the three iPM lasers 2C constituting the light source group 203, one iPM laser 2C located at the first end in the arrangement direction is located on the second end side of the three iPM lasers 2A constituting the light source group 201, and is aligned in a row with these iPM lasers 2A.

[0160] According to the configuration of this modification, the light source groups 201 to 204 can be densely arranged, which contributes to miniaturization of the light receiving and emitting module.

[0161] Fig. 50 is a perspective view showing the configuration of a light receiving and emitting module 1J according to another modified example of the fourth embodiment. This modified example differs from the fourth embodiment in the arrangement of the light source groups 201-204. That is, in this modified example, the light source groups 201-204 do not surround the image sensor 51, but are arranged in the same manner as the light source device 1F shown in Fig. 47. The image sensor 51 is arranged away from the light source groups 201-204. Even with this configuration, it is possible to achieve the same effects as the fourth embodiment.

[0162] The problems that the second embodiment and its modified examples, the third embodiment and its modified examples, and the fourth embodiment and its modified examples described above aim to solve, and the means for solving the problems, will be described below. [Problem to be solved]

[0163] For example, as disclosed in Patent Document 1 and Non-Patent Document 3, a three-dimensional shape measurement method using a stripe pattern is known. In this measurement method, light including a stripe pattern in which multiple bright lines are arranged is projected onto the object to be measured, and images are taken while changing the phase of the stripe pattern, etc. The three-dimensional shape is calculated using a predetermined formula based on the multiple images thus obtained. For example, a phase shift method in which light including a stripe pattern in which multiple bright lines are arranged periodically is projected onto the object to be measured, and images are taken while shifting the phase of the stripe pattern (i.e., the position of the bright lines in the arrangement direction), makes it possible to measure the three-dimensional shape with extremely high accuracy, such as one-hundredth of the spacing between the bright lines.

[0164] In such measurements, it is conceivable to output multiple stripe patterns with different phases, or multiple stripe elements for forming these stripe patterns, from multiple light sources. In this case, the multiple light sources are arranged side by side in a direction intersecting the optical axis. An example of such a light source is an iPM laser. However, when multiple light sources are arranged side by side in a direction intersecting the optical axis, the positions of the light sources in the same direction are inevitably shifted from each other by the light source arrangement pitch. If the positional shift between the multiple light sources causes a positional shift between the multiple stripe patterns, the measurement error will increase.

[0165] The disclosure of the present embodiment aims to provide a light source device, a light receiving and emitting module, and a three-dimensional shape measuring device that can reduce measurement errors in three-dimensional shape measurement using a stripe pattern. [Means for solving the problem]

[0166] [1] The light source device according to this embodiment is a light source device used for three-dimensional shape measurement, a plurality of first light sources arranged side by side in a direction intersecting the optical axis direction so that the optical axis directions of the first light sources are aligned, the plurality of first light sources project light including a first pattern in which a plurality of bright lines are arranged along a first direction intersecting with an extension direction of the bright lines onto a common projection area; The plurality of first light sources are light source devices arranged along a second direction perpendicular to the first direction.

[0167] In the light source device of [1] above, the multiple first light sources are arranged along a second direction perpendicular to the first direction, which is the arrangement direction of the bright lines of the first pattern. In this case, even if the positions of the first light sources are shifted from each other by the arrangement pitch, the direction of the shift is perpendicular to the arrangement direction of the bright lines of the first pattern. Therefore, even if the position of the first patterns among the multiple first light sources is shifted, the shift does not affect the calculation of the three-dimensional shape. Therefore, the light source device of [1] above can reduce measurement errors in three-dimensional shape measurement.

[0168] [2] In the light source device of [1] above, the plurality of first light sources may project onto a common projection area light including a first pattern in which a plurality of bright lines are aligned along a first direction intersecting with the extension direction of the bright lines, and the intervals between the plurality of bright lines in the first pattern may be equal among the plurality of first light sources. By projecting light including such a first pattern from the plurality of first light sources onto a common projection area, three-dimensional shape measurement using the phase shift method can be suitably performed.

[0169] [3] The light source device of [1] or [2] above may include a plurality of iPM lasers as a plurality of first light sources. In this case, the light source that outputs light including the first pattern can be made smaller, and thus the light source device can be made smaller.

[0170] [4] In any of the light source devices [1] to [3] above, the multiple iPM lasers may be formed monolithically. In this case, the multiple iPM lasers are formed in a single element, which makes it easier to assemble the light source device. Furthermore, positional errors can be reduced compared to when individual elements are combined and mounted.

[0171] [5] In the light source device of any one of [1] to [4] above, the number of the first light sources may be n, and the amount of shift of the emission lines between the first light sources may be 1 / n of the interval between the emission lines. In this case, three-dimensional shape measurement using the phase shift method can be suitably performed.

[0172] [6] Any of the light source devices [1] to [5] above may further include a plurality of second light sources arranged side by side in a direction intersecting the optical axis direction so that their optical axis directions are aligned. The plurality of second light sources project light including a second pattern in which a plurality of bright lines are arranged along a third direction intersecting the extension direction of the bright lines onto a common projection area. The plurality of second light sources are arranged along a fourth direction perpendicular to the third direction. In the light source device of [6] above, the plurality of second light sources are arranged along a fourth direction perpendicular to the third direction, which is the arrangement direction of the bright lines of the second pattern. In this case, even if the positions of the respective second light sources are shifted by the arrangement pitch, the direction of the shift is perpendicular to the arrangement direction of the bright lines of the second pattern. Therefore, even if the position of the second patterns among the plurality of second light sources is shifted, the shift does not affect the calculation of the three-dimensional shape. Therefore, the light source device of [6] above can reduce measurement errors in three-dimensional shape measurement.

[0173] [7] In the light source device of [6] above, the spacing between the multiple bright lines of the second pattern may be equal among the multiple second light sources. The positions of the multiple bright lines in the third direction, based on the optical axis of each second light source, may be different among the multiple second light sources. By projecting light including such a second pattern from the multiple second light sources onto a common projection area, three-dimensional shape measurement using the phase shift method can be suitably performed. In other words, three-dimensional shape measurement using the phase shift method can be performed at least twice using two light source groups, such as a light source group consisting of multiple first light sources and a light source group consisting of multiple second light sources, to improve measurement accuracy.

[0174] [8] In the light source device of [6] above, the spacing between the multiple bright lines in the second pattern may be different from the spacing between the multiple bright lines in the first pattern. In this case, three-dimensional shape measurement using the phase shift method can be performed using two types of stripe patterns with different spacing between the bright lines, thereby further improving measurement accuracy.

[0175] [9] In any of the light source devices [7] to [8] above, the third direction may intersect with the first direction. In this case, three-dimensional shape measurement can be performed using two types of stripe patterns with different emission line arrangement directions, thereby further improving measurement accuracy.

[0176]

[10] A light receiving and emitting module according to an embodiment of the present disclosure is a light receiving and emitting module used for three-dimensional shape measurement, and includes any one of the light source devices described above and an image sensor that captures an image of a first pattern projected onto a common projection area and generates image data. The light source device and the image sensor are provided on a common substrate. By including any one of the light source devices described above, this light receiving and emitting module can reduce the size of the optical device and measurement errors in three-dimensional shape measurement.

[0177]

[11] A three-dimensional shape measurement device according to an embodiment of the present disclosure includes the image data generation device described above and a data generation unit that generates three-dimensional shape data using image data output from the image data generation device. By including any one of the light source devices described above, this image data generation device can reduce measurement errors in three-dimensional shape measurement. [Explanation of symbols]

[0178] REFERENCE SIGNS LIST 1, 1A...semiconductor light emitting device, 1C to 1F...light source device, 1G, 1H, 1J...light receiving and emitting module, 2, 2A to 2D...iPM laser, 2a...first surface, 2b...second surface, 3...drive circuit, 6...support substrate, 6a...third surface, 6b...fourth surface, 20...semiconductor substrate, 21...first cladding layer, 22...active layer, 23...second cladding layer, 25A, 25B...phase modulation layer, 25a...basic layer, 25b...modified refractive index area, 26...second electrode, 27...first electrode, 31, 31A, 31B...current source circuit, 32...current mirror circuit, 33...oscillation prevention circuit, 34...switch operation unit, 34a...first shift register, 34b...second shift register, 50...imaging unit, 51...imaging element, 201 to 204...light source group, 311...operational amplifier, 312...NMOS-FET, 314 a to 314d...third switches, 316a to 316d...partial circuit, 317...digital-analog converter, 318...serial-parallel converter, 322...switch section, 322a...first switch, 322b...second switch, 323...first current path, 324...second current path, 331...NMOS-FET, 332...first PMOS-FET, 333...second PMOS-FET, D...straight line, D1, D2, D11, D12, D21, D22, D31, D32, D41, D42...direction, G...center of gravity, Iout...driving current, L1...light, O(x, y)...lattice point, r(x, y)...distance, Rop...resistor section, Rop1 to Rop4...resistor, S4...serial signal, S6...parallel signal, Vop...input voltage, WL1, WL2...bright line, φ(x, y)...angle.

Claims

1. a plurality of iPM lasers each having a first surface and a second surface opposite to the first surface, and each outputting light from the first surface; a drive circuit that supplies a drive current for causing each of the plurality of iPM lasers to emit light; The drive circuit a current source circuit common to the plurality of iPM lasers; a plurality of switch units provided corresponding to the plurality of iPM lasers, respectively, for switching on / off the drive current; a switch operating section that operates each of the plurality of switch sections individually.

2. each of the plurality of switch units includes a first switch and a second switch connected in series with the first switch; The switch operating unit a first shift register that operates the first switch; a second shift register that operates the second switch; The semiconductor light emitting device according to claim 1 ,

3. the drive circuit further includes a plurality of current mirror circuits respectively corresponding to the plurality of iPM lasers; Each of the plurality of current mirror circuits has a first current path and a second current path through which a current flows, the magnitude of the current being proportional to the magnitude of the current flowing through the first current path; the first current path is connected to the common current source circuit, and the switch unit is provided on the first current path; 3. The semiconductor light emitting device according to claim 1, wherein the second current path is connected to the iPM laser corresponding to the current mirror circuit among the plurality of iPM lasers.

4. the drive circuit further includes a plurality of oscillation prevention circuits respectively corresponding to the plurality of iPM lasers; Each of the plurality of oscillation prevention circuits an NMOS-FET including a source terminal connected to an anode terminal of each of the plurality of iPM lasers and a drain terminal connected to a first constant potential line; a first PMOS-FET including a gate terminal connected to the source terminal of the NMOS-FET and a drain terminal connected to a second constant potential line having a lower potential than the first constant potential line; a second PMOS-FET including a drain terminal connected to the source terminal of the first PMOS-FET, a source terminal connected to a third constant potential line having a higher potential than the second constant potential line, and a gate terminal, the second PMOS-FET supplying a current to the first PMOS-FET in response to an input voltage to the gate terminal; 3. The semiconductor light emitting device according to claim 1, wherein a potential between the first PMOS-FET and the second PMOS-FET is supplied to a gate terminal of the NMOS-FET.

5. 3. The semiconductor light emitting device according to claim 1, wherein the value of the current generated by said common current source circuit is variable.

6. The common current source circuit comprises: an operational amplifier having a pair of input terminals to which an input voltage is supplied; a transistor having a control terminal connected to the output terminal of the operational amplifier; a resistor unit having one end connected to the current terminal of the transistor and the other input terminal of the operational amplifier, and the other end connected to a fourth constant potential line, The resistance value of the resistor section is variable, 6. The semiconductor light emitting device according to claim 5, wherein the switching operation of the plurality of switch sections and the operation of changing the resistance value of the resistor section are synchronized.

7. the resistor section includes a plurality of partial circuits connected in parallel to each other between the one end and the other end of the resistor section, each of the plurality of partial circuits includes a resistor and a third switch connected in series between the one end and the other end of the resistor portion; The semiconductor light emitting device according to claim 6 , wherein the switching operations of the plurality of switch sections and the switching operation of the third switch are synchronized.

8. The common current source circuit comprises: an operational amplifier having a pair of input terminals to which an input voltage is supplied; a transistor having a control terminal connected to the output terminal of the operational amplifier; a resistor having one end connected to the current terminal of the transistor and the other input terminal of the operational amplifier, and the other end connected to a fourth constant potential line; 6. The semiconductor light emitting device according to claim 5, wherein the switching operation of said plurality of switch sections and the operation of switching the value of said input voltage are synchronized.

9. The drive circuit a serial-to-parallel converter for converting a serial signal containing digital data representing an indication value of a current for the common current source circuit into a parallel signal; a digital-to-analog converter for converting the digital data converted into the parallel signal into an analog signal, 6. The semiconductor light emitting device according to claim 5, wherein the common current source circuit generates a current having a magnitude corresponding to the instruction value based on the analog signal.

10. Each of the plurality of iPM lasers an active layer which is a light-emitting portion; a phase modulation layer optically coupled to the active layer; a first clad layer located on the first surface side of the active layer and the phase modulation layer; a second clad layer located on the second surface side of the active layer and the phase modulation layer; a second electrode located on the second surface side of the second clad layer; a first electrode located on the first surface side of the first clad layer, The phase modulation layer is The base layer and a plurality of modified refractive index areas provided in the base layer so as to be two-dimensionally distributed on a plane perpendicular to the normal direction of the first surface, the modified refractive index areas having a refractive index different from that of the base layer; in a state where a virtual square lattice is set on the surface, the plurality of modified refractive index areas are arranged such that the centers of gravity of the respective plurality of modified refractive index areas are spaced a predetermined distance from corresponding lattice points, and angles around each lattice point in the virtual square lattice, of line segments connecting the centers of gravity of the respective plurality of modified refractive index areas and the corresponding lattice points, with respect to the virtual square lattice are set in accordance with a phase distribution for forming an optical image, The semiconductor light emitting device according to claim 1 , wherein at least two of the angles in the plurality of modified refractive index areas are different from each other.

11. Each of the plurality of iPM lasers an active layer which is a light-emitting portion; a phase modulation layer optically coupled to the active layer; a first clad layer located on the first surface side of the active layer and the phase modulation layer; a second clad layer located on the second surface side of the active layer and the phase modulation layer; a second electrode located on the second surface side of the second clad layer; a first electrode located on the first surface side of the first clad layer, The phase modulation layer is The base layer and a plurality of modified refractive index areas provided in the base layer so as to be two-dimensionally distributed on a plane perpendicular to the normal direction of the first surface, the modified refractive index areas having a refractive index different from that of the base layer; In a state where a virtual square lattice is set on the surface, the plurality of modified refractive index areas are arranged such that the centers of gravity of the respective plurality of modified refractive index areas pass through corresponding lattice points and are positioned on a straight line inclined to the virtual square lattice, and the distance along the straight line between the centers of gravity of the respective plurality of modified refractive index areas and the corresponding lattice points is set in accordance with a phase distribution for forming an optical image, 3. The semiconductor light emitting device according to claim 1, wherein the gradient of the straight line is uniform in the plurality of modified refractive index areas.

12. 3. The semiconductor light emitting device according to claim 1, wherein each of the plurality of iPM lasers is monolithically formed.

13. The semiconductor light emitting device according to claim 12 , wherein the plurality of iPM lasers and the driving circuit are mounted on a common substrate.

14. a support substrate including a third surface and a fourth surface opposite the third surface; The semiconductor light-emitting device according to claim 1 , wherein the plurality of iPM lasers are individually mounted on the third surface such that the second surface faces the third surface.

15. The semiconductor light emitting device according to claim 14 , wherein the drive circuit is provided on the third surface or the fourth surface of the support substrate.

16. 3. The semiconductor light emitting device according to claim 1, wherein the drive circuit is connected to the plurality of iPM lasers by bump bonding.

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