Light projection / receiving module for distance measurement and distance measuring device

Abstract

A light projection and reception module comprises a wiring board with a main surface, a semiconductor laser unit provided on the main surface and configured to emit laser light from an edge surface intersecting the main surface, a reflection block provided on the main surface, the reflection block having a reflective surface inclined with respect to the main surface and configured to reflect the laser light from the semiconductor laser unit to one side opposite the wiring board, a collimation lens provided on the main surface and positioned between the semiconductor laser unit and the reflection block, and a light reception sensor provided on the main surface and configured to detect the laser light emitted by the semiconductor laser unit passing through the collimation lens, being reflected by the reflective surface of the reflection block, and then being reflected by an object.to detect.

Description

Distance measurement light emitting / receiving module and distance measurement device

[0001] One aspect of the present disclosure relates to a distance measurement light emitting and receiving module and a distance measuring device.

[0002] Patent Document 1 describes a lidar sensor that measures the distance to an object using a time-of-flight (TOF) method. This lidar sensor includes a light source and a detector mounted on a board. A lens assembly is disposed above the light source and the detector. Light emitted from the light source passes through the lens assembly, is reflected by the object, and then enters the detector.

[0003] Special Publication No. 2022-525426

[0004] The above-mentioned apparatus is required to meet various requirements, such as improved yield and high accuracy in the placement of each element.

[0005] Therefore, an object of one aspect of the present disclosure is to provide a distance measurement light emitting and receiving module and a distance measuring device in which each element can be suitably arranged.

[0006] A ranging light projecting and receiving module according to one aspect of the present disclosure is [1] "a ranging light projecting and receiving module comprising: a wiring board having a main surface; a semiconductor laser unit provided on the main surface and emitting laser light from a side surface intersecting the main surface; a reflection block provided on the main surface, the reflection block having a reflection surface inclined with respect to the main surface and reflecting the laser light from the semiconductor laser unit to the opposite side from the wiring board; a collimating lens provided on the main surface and positioned between the semiconductor laser unit and the reflection block; and a light receiving sensor provided on the main surface, detecting the laser light emitted from the semiconductor laser unit, passing through the collimating lens, reflected by the reflection surface of the reflection block, and then reflected by an object."

[0007] In this ranging light-emitting / receiving module, the semiconductor laser unit, the reflecting block, the collimating lens, and the light-receiving sensor are all disposed on the main surface of a wiring substrate. This improves yield compared to, for example, a case in which the semiconductor laser unit and the collimating lens are disposed on one substrate and the light-receiving sensor is disposed on another substrate and then these substrates are combined to form a light-emitting / receiving module. Furthermore, the semiconductor laser unit is disposed on the main surface so as to emit laser light from a side surface intersecting the main surface, and the laser light from the semiconductor laser unit is reflected by the reflecting block toward the opposite side of the wiring substrate. This allows the collimating lens to be disposed on the main surface. As a result, the collimating lens can be positioned with greater precision compared to, for example, a case in which a separate collimating lens is disposed away from the wiring substrate. Furthermore, the laser light from the semiconductor laser unit is reflected by the reflecting block toward the opposite side of the wiring substrate. This reduces attenuation of the laser light within the wiring substrate and ensures the intensity of the laser light, compared to, for example, a case in which the laser light from the semiconductor laser unit is reflected by the reflecting block toward the wiring substrate and then transmitted through the wiring substrate to be emitted to the outside. In this way, with this distance measurement light emitting and receiving module, each element can be suitably arranged.

[0008] A ranging light-emitting and receiving module according to one aspect of the present disclosure may be [2] "the ranging light-emitting and receiving module according to [1]," in which the reflecting block is located between the collimating lens and the light-receiving sensor." In this case, a long distance can be ensured between the semiconductor laser unit and the light-receiving sensor, thereby preventing heat generated in the semiconductor laser unit from affecting the light-receiving sensor. Furthermore, the semiconductor laser unit may emit laser light not only toward the collimating lens but also toward the opposite side of the collimating lens. For example, if the light-receiving sensor is located on the opposite side of the collimating lens from the semiconductor laser unit, there is a concern that the light emitted toward the opposite side of the collimating lens may be detected as stray light by the light-receiving sensor. In contrast, in the ranging light-emitting and receiving module according to [2], the reflecting block is located between the semiconductor laser unit and the light-receiving sensor, thereby preventing such a situation from occurring. Furthermore, the reflecting block can also block light from outside the ranging light-emitting and receiving module from entering the light-receiving sensor.

[0009] A ranging light emitting / receiving module according to one aspect of the present disclosure may be [3] "the ranging light emitting / receiving module according to [1] or [2], in which the reflecting block is configured as a separate member from the wiring board and fixed to the main surface." For example, if the reflecting block is configured as a common member with the wiring board, the amount of processing required to form the reflecting block increases. Furthermore, the reflecting block cannot be formed from a material other than that of the wiring board. In contrast, in the light emitting / receiving module of [3], for example, the reflecting block can be formed from a material other than that of the wiring board, making it possible to select a suitable material and processing method for the reflecting block, thereby improving the forming accuracy and characteristics of the entire ranging light emitting / receiving module. Furthermore, for example, if the reflecting block is configured as a common member with the wiring board, careful attention must be paid when applying a metal coating to the reflecting block to prevent electrical conduction between the metal coating and elements on the main surface. In contrast, in the light emitting / receiving module of [3], the reflecting block is configured as a separate member from the wiring board, eliminating such care and facilitating processing.

[0010] A ranging light emitting and receiving module according to one aspect of the present disclosure may be [4] "the ranging light emitting and receiving module according to any one of [1] to [3], in which the wiring board and the reflecting block are formed of different materials." In this case, it is possible to select a material and processing method suitable for the reflecting block, thereby improving the forming accuracy and characteristics of the ranging light emitting and receiving module as a whole.

[0011] A ranging light emitting and receiving module according to one aspect of the present disclosure may be [5] "the ranging light emitting and receiving module according to any one of [1] to [4], wherein the reflecting block has a flat surface on the side opposite to the wiring board." In this case, for example, when fixing the reflecting block to the wiring board, the flat surface can be adsorbed by a pickup device, so that the reflecting block can be easily picked up and placed in a predetermined position.

[0012] A ranging light emitting and receiving module according to one aspect of the present disclosure may be [6] "the ranging light emitting and receiving module according to any one of [1] to [5], wherein the reflective block is formed of reflectively coated silicon." In this case, the reflective block can be formed with high precision.

[0013] The distance measurement light emitting and receiving module according to one aspect of the present disclosure may be [7] "the distance measurement light emitting and receiving module according to any one of [1] to [6], including a plurality of the semiconductor laser units." In this case, the total intensity of the laser light can be increased.

[0014] A ranging light emitting and receiving module according to one aspect of the present disclosure may be [8] "the ranging light emitting and receiving module according to [7], including a plurality of the reflecting blocks, each of which corresponds one-to-one to the semiconductor laser units and reflects the laser light from the corresponding semiconductor laser units." In this case, material costs can be reduced compared to, for example, a case in which one reflecting block is provided corresponding to the plurality of semiconductor laser units.

[0015] A ranging light emitting and receiving module according to one aspect of the present disclosure may be [9] "the ranging light emitting and receiving module according to [7], wherein the reflecting block reflects the laser light from the plurality of semiconductor laser units." In this case, it is only necessary to provide one reflecting block corresponding to the plurality of semiconductor laser units, and therefore the reflecting block can be easily and accurately fixed to the wiring board.

[0016] A ranging light projecting and receiving module according to one aspect of the present disclosure may be

[10] "the ranging light projecting and receiving module according to any one of [7] to [9], including a plurality of collimating lenses, each of which corresponds one-to-one to the semiconductor laser units and collimates the laser light from the corresponding semiconductor laser units." For example, if one collimating lens is provided corresponding to a plurality of semiconductor laser units, even when only one semiconductor laser unit is operating, the laser light from the semiconductor laser unit may be reflected within the collimating lens, causing the entire collimating lens to emit light. In contrast, the ranging light projecting and receiving module according to

[10] can prevent such a situation from occurring.

[0017] A ranging light emitting and receiving module according to one aspect of the present disclosure may be

[11] "the ranging light emitting and receiving module according to any one of [7] to [9], wherein the collimating lens collimates the laser light from the plurality of semiconductor laser units." In this case, it is only necessary to provide one collimating lens corresponding to the plurality of semiconductor laser units, and therefore the collimating lens can be easily and accurately fixed to the wiring board.

[0018] A ranging light projecting and receiving module according to one aspect of the present disclosure may be

[12] "the ranging light projecting and receiving module according to any one of [1] to

[11] , in which a resin material is disposed between the collimating lens and the semiconductor laser unit." In this case, for example, by making the refractive index of the resin material greater than the refractive index of air and equal to or less than the refractive index of the collimating lens, reflection of the laser light entering the collimating lens can be suppressed. If the refractive index of the resin material is greater than the refractive index of air, the divergence angle of the laser light from the semiconductor laser unit can also be reduced.

[0019] A ranging light projecting and receiving module according to one aspect of the present disclosure may be

[13] "the ranging light projecting and receiving module according to any one of [1] to

[12] , wherein a recess recessed toward the semiconductor laser unit is formed on a surface of the collimating lens opposite to the semiconductor laser unit." In this case, the intensity distribution of the laser light can be adjusted to a desired shape by the collimating lens.

[0020] A ranging light emitting / receiving module according to one aspect of the present disclosure may be

[14] "the ranging light emitting / receiving module according to any one of [1] to

[13] , wherein the semiconductor laser unit includes a submount substrate and a laser element mounted on the submount substrate, and the laser element is mounted on the main surface of the wiring substrate in the submount substrate." In this case, heat generated in the laser element can be prevented from affecting the light receiving sensor. Furthermore, since the submount substrate is disposed between the laser element and the wiring substrate, interference between the laser light emitted from the laser element and the wiring substrate before entering the collimating lens can be prevented. Furthermore, compared to, for example, a case in which the laser element is directly mounted on the wiring substrate, a burn-in test can be performed before the laser element is fixed to the wiring substrate, allowing only the semiconductor laser unit that passes the burn-in test to be used.

[0021] A ranging light emitting and receiving module according to one aspect of the present disclosure may be

[15] "the ranging light emitting and receiving module according to any one of [1] to

[14] , further including a bandpass filter disposed on the opposite side of the light receiving sensor from the wiring board, the bandpass filter being supported by a pair of supports provided on the main surface so as to sandwich the light receiving sensor." In this case, the bandpass filter can block light of wavelengths other than the wavelength to be detected, thereby improving detection efficiency. Furthermore, because the bandpass filter is supported by a pair of supports provided on the main surface so as to sandwich the light receiving sensor, it is possible to suppress interference of the bandpass filter with wires connecting the light receiving sensor to the wiring board, for example.

[0022] A ranging light emitting and receiving module according to one aspect of the present disclosure may be

[16] "the ranging light emitting and receiving module according to any one of [1] to

[14] , further including a layered bandpass filter formed on the light receiving section of the light receiving sensor." In this case, the bandpass filter can block light of wavelengths other than the wavelength to be detected, thereby improving detection efficiency. Furthermore, because the bandpass filter is formed on the light receiving section of the light receiving sensor, the bandpass filter can be formed well.

[0023] A ranging light emitting and receiving module according to one aspect of the present disclosure may be

[17] "the ranging light emitting and receiving module according to any one of [1] to

[14] , further comprising a bandpass filter placed on the light receiving section of the light receiving sensor." In this case, the bandpass filter can block light of wavelengths other than the wavelength to be detected, thereby improving detection efficiency.

[0024] A distance measuring device according to one aspect of the present disclosure is

[18] "a distance measuring device comprising a distance measuring light emitting and receiving module according to any one of [1] to

[17] and a control unit that calculates the distance to the target object based on the detection result of the laser light by the light receiving sensor." With this distance measuring device, for the reasons described above, each element in the distance measuring light emitting and receiving module can be suitably arranged.

[0025] According to one aspect of the present disclosure, it is possible to provide a distance measurement light emitting and receiving module and a distance measuring device in which each element can be suitably arranged.

[0026] FIG. 1 is a configuration diagram of a distance measuring device according to an embodiment; FIG. 2 is a perspective view of a light emitting and receiving module as seen from the front side; FIG. 3 is a perspective view of a light emitting and receiving module as seen from the back side; FIG. 4 is a perspective view of a semiconductor laser unit as seen from the front side; FIG. 5 is a perspective view of a semiconductor laser unit as seen from the back side; FIG. 6 is a diagram for explaining the arrangement of each element; FIG. 7 is a perspective view of a light emitting and receiving module according to a modified example;

[0027] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the following description, the same or equivalent elements will be designated by the same reference numerals, and redundant description will be omitted.

[0028] 1, the distance measuring device 1 includes a light emitting / receiving module 2 (a light emitting / receiving module for distance measurement) and a control unit 3. In the distance measuring device 1, a laser light L is emitted (projected) from a semiconductor laser unit 20 of the light emitting / receiving module 2. After being reflected by an object S, the laser light L is detected (received) by a light receiving sensor 50 of the light emitting / receiving module 2.

[0029] The control unit 3 calculates the distance from the distance measuring device 1 (light emitting and receiving module 2) to the target S based on the detection result of the laser light L by the light receiving sensor 50. In this example, the distance measuring device 1 is a LiDAR (Light Detection And Ranging) device that measures the distance to the target S using a TOF method, and the control unit 3 calculates the distance to the target S based on the time of flight of the laser light L (the time from when it is emitted from the semiconductor laser unit 20 to when it is detected by the light receiving sensor 50). The control unit 3 is configured, for example, by a microcomputer provided on a circuit board. In the distance measuring device 1, the light emitting and receiving module 2 is mounted on the circuit board, and the control unit 3 is electrically connected to the light emitting and receiving module 2.

[0030] As shown in FIG. 2 , the light emitting / receiving module 2 includes a wiring substrate 10, multiple semiconductor laser units 20, multiple reflecting blocks 30, multiple collimating lenses 40, multiple light receiving sensors 50, and a bandpass filter 60. In this example, the semiconductor laser units 20, the reflecting blocks 30, the collimating lenses 40, and the light receiving sensors 50 are provided in equal numbers (four each). The following description will be made with reference to the X direction, Y direction (direction perpendicular to the X direction), and Z direction (direction perpendicular to the X and Y directions) shown in each figure. For ease of understanding, in FIG. 2 , the sealing resin 28 of the semiconductor laser units 20, the collimating lenses 40, and the bandpass filter 60 are indicated by two-dot chain lines. This also applies to FIG. 7 (described later) and the sealing resin 28 in FIGS. 3 and 4 (described later).

[0031] The wiring substrate 10 is formed, for example, in the shape of a rectangular plate with long sides parallel to the X direction, and has a main surface 11 and a main surface 12. The main surface 11 is the surface on one side in the Z direction, and the main surface 12 is the surface opposite to the main surface 11 (back surface). The main surfaces 11 and 12 are, for example, flat surfaces perpendicular to the Z direction. The wiring substrate 10 is, for example, a glass epoxy substrate or a ceramic substrate. When the wiring substrate 10 is a ceramic substrate, the thermal conductivity of the ceramic substrate is higher than that of air, so that heat generated in the semiconductor laser section 20 can be efficiently dissipated. An alignment mark 18 formed, for example, by gold plating is provided on the main surface 11. The alignment mark 18 is used as a reference for positioning when the semiconductor laser section 20, the reflection block 30, the collimator lens 40, and the light receiving sensor 50 are fixed to the main surface 11 by die bonding.

[0032] The semiconductor laser unit 20 is provided on the main surface 11 and emits laser light L in a direction parallel to the main surface 11. In this example, the semiconductor laser unit 20 emits laser light L in the Y direction. As shown in FIG. 4 , the semiconductor laser unit 20 has a chip-on-board (COB) structure and includes a submount substrate 21 (board) and a laser element 22 (chip) mounted on the submount substrate 21. The submount substrate 21 is formed in the shape of a rectangular plate (rectangular parallelepiped) with long sides parallel to the X direction, for example.

[0033] The laser element 22 is, for example, an edge-emitting semiconductor laser that emits laser light L from an end face 22a (side face) in the Y direction. The end face 22a is a side face that intersects with the main surface 11 of the wiring substrate 10 and, in this example, is a flat surface perpendicular to the main surface 11 (perpendicular to the Y direction). The end face 22a may intersect with the main surface 11 at an angle other than perpendicular. The laser element 22 is, for example, a pulsed laser diode and emits laser light L, which is pulsed light. The laser element 22 is electrically connected via multiple (four in this example) wires 25 to an anode electrode 23 and a cathode electrode 24 that are provided on the surface 21a of the submount substrate 21 so as to sandwich the laser element 22 in the X direction. The laser element 22 is also disposed on the submount substrate 21 via a ground electrode 26 and is electrically connected to the ground electrode 26.

[0034] A pair of insulating members 27 are further provided on the surface 21a of the submount substrate 21, located between the anode electrode 23 and the ground electrode 26 and between the cathode electrode 24 and the ground electrode 26, respectively. The pair of insulating members 27 electrically insulate the anode electrode 23 from the ground electrode 26 and the cathode electrode 24 from the ground electrode 26, respectively. As in the example of FIG. 4 , the surface 21a of the submount substrate 21 may be exposed except for the areas where the electrodes (anode electrode 23, cathode electrode 24, and ground electrode 26) and the insulating members 27 are arranged, or the entire surface 21a except for the areas where the electrodes are arranged may be covered by the insulating member 27.

[0035] A sealing resin 28 (mold resin) is further provided on the surface 21a of the submount substrate 21. The sealing resin 28 is provided, for example, over the entire surface 21a, and covers and seals the laser element 22, the anode electrode 23, the cathode electrode 24, the ground electrode 26, and the insulating member 27. The sealing resin 28 is formed, for example, in a rectangular parallelepiped shape, and the semiconductor laser portion 20 as a whole is formed in a rectangular parallelepiped shape.

[0036] As shown in FIG. 5 , a plurality of electrodes 29 (six in this example) are provided on the surface 21b of the submount substrate 21. The surface 21b is the surface (back surface) opposite the surface 21a. Each electrode 29 is formed, for example, in a circular shape. In this example, the plurality of electrodes 29 are arranged in three rows along the X direction, each row consisting of two electrodes 29 aligned along the Y direction. The two electrodes 29A aligned along the Y direction are arranged to overlap the anode electrode 23 in the Z direction and are electrically connected to the anode electrode 23. The two electrodes 29B aligned along the Y direction are arranged to overlap the ground electrode 26 in the Z direction and are electrically connected to the ground electrode 26. The two electrodes 29C aligned along the Y direction are arranged to overlap the cathode electrode 24 in the Z direction and are electrically connected to the cathode electrode 24. These electrodes 29 are connected by solder bumps to a plurality of electrodes 13 (six in this example) provided on the main surface 11 of the wiring substrate 10 (see FIG. 6 ), whereby the semiconductor laser section 20 is mounted on the wiring substrate 10. The electrodes 13 are arranged corresponding to the arrangement of the electrodes 29. The semiconductor laser section 20 is fixed to the main surface 11 at the surface with the largest area (surface 21b of the submount substrate 21 in this example).

[0037] The wiring substrate 10 has through holes formed therein that pass through the wiring substrate 10 along the Z direction at positions that overlap with the electrodes 13 in the Z direction. The electrodes 13 are electrically connected to electrode pads 14 (see FIG. 3 ) provided on the main surface 12 of the wiring substrate 10 via the through holes. In this example, three electrode pads 14 are provided corresponding to one laser element 22, for a total of 12 electrode pads 14. The 12 electrode pads 14 are arranged at equal intervals along the X direction.

[0038] The three electrode pads 14 corresponding to one laser element 22 are electrically connected to the anode electrode 23, cathode electrode 24, and ground electrode 26 of the corresponding laser element 22. More specifically, electrodes 29A, 29B, and 29C are electrically connected to the electrode pads 14 via electrodes 13, respectively, and thereby the anode electrode 23, cathode electrode 24, and ground electrode 26 are each electrically connected to the electrode pads 14. At least three electrodes 29 are required to electrically connect the anode electrode 23, cathode electrode 24, and ground electrode 26 to the electrode pads 14, but providing six electrodes 29 as in the example of Figure 5 can improve the stability of the electrical connection and heat dissipation.

[0039] The reflecting blocks 30 are provided on the main surface 11 of the wiring substrate 10. In this example, four reflecting blocks 30 are arranged in a line at equal intervals along the X direction. The four reflecting blocks 30 correspond one-to-one to the four semiconductor laser units 20 and face the corresponding semiconductor laser units 20 in the Y direction with a collimating lens 40 sandwiched therebetween. Furthermore, the four reflecting blocks 30 correspond one-to-one to the four collimating lenses 40 and one-to-one to the four light-receiving sensors 50, and are positioned between the corresponding collimating lens 40 and the corresponding light-receiving sensor 50. In other words, in this example, the corresponding semiconductor laser units 20, collimating lenses 40, reflecting blocks 30, and light-receiving sensors 50 are lined up in this order in the Y direction.

[0040] The reflective block 30 is a micromirror formed by wet etching a silicon material, for example, and has a reflective surface 31, a flat surface 32, a bottom surface 33, and side surfaces 34. The reflective block 30 is configured as a separate member from the wiring substrate 10, and the bottom surface 33 is fixed to the main surface 11 of the wiring substrate 10 by die bonding. That is, in this example, the reflective block 30 is not formed as a common (single) member with the wiring substrate 10 by integral molding. Furthermore, the reflective block 30 is formed from a material different from that of the wiring substrate 10.

[0041] The reflective surface 31 extends at an incline relative to the main surface 11 of the wiring substrate 10. In this example, the reflective surface 31 is inclined at 45 degrees relative to the main surface 11. A reflective film (Au film) made of gold is provided on the reflective surface 31, thereby allowing the reflective surface 31 to reflect the laser light L. The reflective film is formed, for example, by applying a metal coating by sputtering to a silicon substrate obtained by wet etching. That is, the reflective block 30 in this example is formed from reflectively coated silicon. The reflective film is formed, for example, on the entire flat surface 32 and a portion of the bottom surface 33, but not on the side surface 34 (surfaces other than the reflective surface 31, flat surface 32, and bottom surface 33). The reflective block 30 reflects the laser light L emitted from the corresponding semiconductor laser unit 20 and transmitted through the collimating lens 40 toward the opposite side of the wiring substrate 10. In this example, the reflective block 30 reflects the laser light L in the Z direction (a direction perpendicular to the main surface 11 of the wiring substrate 10). The reflective film (reflective coating) is not limited to a metal coating made of gold, but may be a metal coating made of other metal materials, or a reflective coating made of a dielectric multilayer film. The material for the reflective coating is not limited to silicon, but may be other materials.

[0042] The flat surface 32 is the surface of the reflecting block 30 opposite to the wiring substrate 10, and extends perpendicular to the Z direction (parallel to the main surface 11 of the wiring substrate 10). The flat surface 32 is formed in a rectangular shape with long sides parallel to the X direction, for example.

[0043] The collimating lenses 40 are provided on the main surface 11 of the wiring substrate 10. In this example, the four collimating lenses 40 are arranged side by side at equal intervals along the X direction. The four collimating lenses 40 correspond one-to-one to the four semiconductor laser units 20 and face the corresponding semiconductor laser unit 20 in the Y direction. Each collimating lens 40 collimates the light from the corresponding semiconductor laser unit 20. The collimating lenses 40 are made of, for example, glass.

[0044] A recess 41 recessed toward the semiconductor laser unit 20 is formed on the surface 40a of the collimating lens 40 opposite the semiconductor laser unit 20. The recess 41 is formed in a semicircular shape when viewed from the Z direction. That is, the recess 41 has an inner surface that is curved in an arc shape when viewed from the Z direction. By refracting the laser light L at this curved surface, the intensity distribution of the laser light L emitted from the collimating lens 40 can be adjusted to a desired shape. In this example, the laser light L emitted from the semiconductor laser unit 20 has a bihedral distribution (a shape with raised portions on both sides of the center) in which the intensity in the center is lower than the intensity in the side portions. After the laser light L passes through the collimating lens 40, the intensity distribution of the laser light L is adjusted to a Gaussian distribution. In other words, the recess 41 is formed in a shape corresponding to the intensity distribution of the laser light L emitted from the semiconductor laser unit 20.

[0045] The collimating lens 40 is disposed away from the corresponding semiconductor laser unit 20 in the Y direction, and a resin material R is disposed between the collimating lens 40 and the semiconductor laser unit 20. The resin material R is formed of, for example, silicone. The material of the resin material R is selected so that the refractive index of the resin material R is greater than the refractive index of air and less than or equal to the refractive index of the collimating lens 40. In this embodiment, the refractive index of the resin material R is greater than or equal to the refractive index of the sealing resin 28 of the semiconductor laser unit 20 and less than or equal to the refractive index of the collimating lens 40.

[0046] The light-receiving sensors 50 are provided on the main surface 11 of the wiring substrate 10. In this example, four light-receiving sensors 50 are arranged in a line at equal intervals along the X direction. The four light-receiving sensors 50 correspond one-to-one to the four semiconductor laser units 20 and face the corresponding semiconductor laser units 20 in the Y direction via the collimator lenses 40 and the reflecting blocks 30. That is, the light-receiving sensors 50 are arranged on the opposite side of the reflecting blocks 30 from the semiconductor laser units 20. The light-receiving sensors 50 are electrically connected by wires 52 to electrodes 15 provided on the main surface 11 adjacent to the light-receiving sensors 50 in the Y direction. The surface (bottom surface) of the light-receiving sensors 50 with the largest area is fixed to the main surface 11. The light-receiving sensors 50 are configured, for example, by avalanche photodiodes.

[0047] The light-receiving sensor 50 has, for example, a circular light-receiving unit 51, and detects the laser light L that has entered the light-receiving unit 51 via the following path: The laser light L emitted from the semiconductor laser unit 20 passes through the collimating lens 40 and travels toward the reflecting surface 31 of the reflecting block 30. The laser light L is then reflected by the reflecting surface 31 and travels toward the target S. The laser light L is then reflected by the target S and returns to the light-emitting and receiving module 2. The laser light L then enters the light-receiving unit 51 and is detected by the light-receiving sensor 50.

[0048] The bandpass filter 60 is disposed on the opposite side of the wiring substrate 10 from the light-receiving sensors 50. The bandpass filter 60 transmits light of wavelengths within a predetermined range while blocking light of wavelengths outside that range. The bandpass filter 60 is formed, for example, in the shape of a rectangular plate with long sides parallel to the X direction and faces the four light-receiving sensors 50 in the Z direction. The bandpass filter 60 is supported by a pair of support members 16 provided on the main surface 11 of the wiring substrate 10 so as to sandwich the four light-receiving sensors 50, and is spaced apart from the four light-receiving sensors 50 in the Z direction. The pair of support members 16 are formed integrally with the wiring substrate 10, for example, by integral molding, and constitute a common member with the wiring substrate 10. Each support member 16 is formed, for example, in the shape of a rectangular parallelepiped with long sides parallel to the Y direction. [Operation and Effects]

[0049] In the light-emitting / receiving module 2, the semiconductor laser unit 20, the reflecting block 30, the collimating lens 40, and the light-receiving sensor 50 are provided on the main surface 11 of the wiring substrate 10. This improves yield compared to, for example, providing the semiconductor laser unit 20 and the collimating lens 40 on one substrate and the light-receiving sensor 50 on another substrate, and then combining these substrates to form a light-emitting / receiving module. When combining these substrates, adjusting the position between the substrates can be difficult, potentially reducing yield. In contrast, the light-emitting / receiving module 2 allows for easy position adjustment of each component. Furthermore, the semiconductor laser unit 20 is provided on the main surface 11 so as to emit laser light L from an end face 22 a intersecting with the main surface 11. The laser light L from the semiconductor laser unit 20 is reflected by the reflecting block 30 toward the opposite side of the wiring substrate 10. This allows the collimating lens 40 to be provided on the main surface 11. As a result, the collimator lens 40 can be positioned with greater precision than, for example, a case in which a separate collimator lens 40 is positioned away from the wiring board 10. Furthermore, the laser light L from the semiconductor laser unit 20 is reflected by the reflection block 30 in the direction opposite the wiring board 10. This makes it possible to suppress attenuation of the laser light L within the wiring board 10 and ensure the intensity of the laser light L, compared to, for example, a case in which the laser light L from the semiconductor laser unit 20 is reflected by the reflection block 30 toward the wiring board 10 and then transmitted through the wiring board 10 to be emitted to the outside. In this way, the light emitting and receiving module 2 allows each element to be positioned appropriately.

[0050] The reflecting block 30 is located between the collimating lens 40 and the light-receiving sensor 50. This ensures a long distance between the semiconductor laser unit 20 and the light-receiving sensor 50, preventing heat generated in the semiconductor laser unit 20 from affecting the light-receiving sensor 50. Furthermore, the semiconductor laser unit 20 may emit laser light L not only toward the collimating lens 40 but also toward the opposite side of the collimating lens 40. For example, if the light-receiving sensor 50 is located on the opposite side of the semiconductor laser unit 20 from the collimating lens 40, there is a concern that the light emitted toward the opposite side of the collimating lens 40 may be detected as stray light by the light-receiving sensor 50. In contrast, in the light-emitting / receiving module 2, the reflecting block 30 is located between the semiconductor laser unit 20 and the light-receiving sensor 50, preventing such a situation from occurring. Furthermore, the reflecting block 30 can also block light from outside the light-emitting / receiving module 2 from entering the light-receiving sensor 50.

[0051] The reflecting block 30 is configured as a separate member from the wiring board 10 and is fixed to the main surface 11. For example, if the reflecting block 30 were a common member to the wiring board 10, the amount of processing required to form the reflecting block 30 would increase. Furthermore, the reflecting block 30 could not be formed from a different material from the wiring board 10. In contrast, in the light-emitting / receiving module 2, the reflecting block 30 can be formed from a different material from the wiring board 10, allowing for the selection of a suitable material and processing method for the reflecting block 30, thereby improving the forming accuracy and characteristics of the entire light-emitting / receiving module 2. Furthermore, for example, if the reflecting block 30 were a common member to the wiring board 10, careful attention must be paid when applying a metal coating to the reflecting block 30 to prevent electrical conduction between the metal coating and elements on the main surface 11. In contrast, in the light-emitting / receiving module 2, the reflecting block 30 is configured as a separate member from the wiring board 10, eliminating the need for such care and facilitating processing.

[0052] The wiring substrate 10 and the reflecting block 30 are formed from different materials, which makes it possible to select a suitable material and processing method for the reflecting block 30, thereby improving the forming accuracy and characteristics of the entire light emitting and receiving module 2.

[0053] The reflecting block 30 has a flat surface 32 on the side opposite to the wiring board 10. As a result, for example, when fixing the reflecting block 30 to the wiring board 10, the reflecting block 30 can be easily picked up and placed in a predetermined position by adsorbing the flat surface 32 with a pickup device.

[0054] The reflective block 30 is made of reflectively coated silicon, which allows the reflective block 30 to be formed with high precision.

[0055] A plurality of semiconductor laser portions 20 are provided, thereby making it possible to increase the total intensity of the laser light L.

[0056] The plurality of reflecting blocks 30 correspond one-to-one to the plurality of semiconductor laser units 20, and reflect the laser light L from the corresponding semiconductor laser units 20. This makes it possible to reduce material costs compared to, for example, a case where one reflecting block 30 is provided corresponding to the plurality of semiconductor laser units 20.

[0057] The plurality of collimating lenses 40 correspond one-to-one to the plurality of semiconductor laser units 20, and collimate the laser light L from the corresponding semiconductor laser units 20. For example, if one collimating lens 40 is provided corresponding to a plurality of semiconductor laser units 20, even when only one semiconductor laser unit 20 is operating, the laser light L from that semiconductor laser unit 20 may be reflected within the collimating lens 40, causing the entire collimating lens 40 to emit light. In contrast, the light emitting and receiving module 2 can prevent such a situation from occurring.

[0058] A resin material R is disposed between the collimator lens 40 and the semiconductor laser unit 20. Thereby, for example, by making the refractive index of the resin material R larger than the refractive index of air and equal to or smaller than the refractive index of the collimator lens 40, it is possible to suppress reflection of the laser light L when it is incident on the collimator lens 40. By making the refractive index of the resin material R larger than the refractive index of air, it is also possible to reduce the divergence angle of the laser light L from the semiconductor laser unit 20.

[0059] A recess 41 recessed toward the semiconductor laser unit 20 is formed on a surface 40a of the collimator lens 40 opposite to the semiconductor laser unit 20. This allows the intensity distribution of the laser light L to be adjusted to a desired shape by the collimator lens 40.

[0060] The semiconductor laser unit 20 has a submount substrate 21 and a laser element 22 mounted on the submount substrate 21, and the submount substrate 21 is mounted on the main surface 11 of the wiring substrate 10. Since the semiconductor laser unit 20 has a chip-on-board structure, heat generated in the laser element 22 is less likely to be released to the outside, and the heat generated in the laser element 22 can be prevented from affecting the light-receiving sensor 50. Furthermore, since the submount substrate 21 is disposed between the laser element 22 and the wiring substrate 10, it is possible to prevent the laser light L emitted from the laser element 22 from interfering with the wiring substrate 10 before entering the collimator lens 40. Furthermore, compared to when the laser element 22 is directly provided on the wiring substrate 10, for example, a burn-in test can be performed before the laser element 22 is fixed to the wiring substrate 10. This allows only semiconductor laser units 20 that pass the burn-in test to be used, thereby reducing total costs.

[0061] A bandpass filter 60 is disposed on the opposite side of the wiring substrate 10 from the light-receiving sensor 50, and the bandpass filter 60 is supported by a pair of support portions 16 provided on the main surface 11 so as to sandwich the light-receiving sensor 50. This allows the bandpass filter 60 to block light of wavelengths other than the wavelength to be detected, thereby improving detection efficiency. Furthermore, because the bandpass filter 60 is supported by a pair of support portions 16 provided on the main surface 11 so as to sandwich the light-receiving sensor 50, it is possible to prevent the bandpass filter 60 from interfering with the wires 52 connecting the light-receiving sensor 50 and the wiring substrate 10, for example. [Modification]

[0062] The light emitting and receiving module 2 may be configured as in the modified example shown in Fig. 7. In this modified example, the semiconductor laser section 20 is made up of a laser element 22 and does not include a submount substrate 21. In other words, the semiconductor laser section 20 is configured of a laser chip (laser element 22). When the semiconductor laser section 20 is a laser chip, heat is less likely to be trapped and heat dissipation is higher than when the semiconductor laser section 20 has a chip-on-board structure (package).

[0063] The semiconductor laser section 20 is electrically connected to an anode electrode 23 and a cathode electrode 24 provided on the main surface 11 of the wiring substrate 10 via multiple (four in this example) wires 25. The semiconductor laser section 20 is also disposed on the main surface 11 via a ground electrode 26 and is electrically connected to the ground electrode 26. The anode electrode 23, the cathode electrode 24, and the ground electrode 26 are electrically connected to electrode pads 14 (see FIG. 3 ) provided on the main surface 12 of the wiring substrate 10 via through holes that penetrate the wiring substrate 10. The through holes are formed so as not to overlap with connection regions with the wires 25 in the Z direction. In this example, the through holes are formed in the lower portions of the anode electrode 23, the cathode electrode 24, and the ground electrode 26 on the opposite side of the collimator lens 40 in the Y direction. This makes it possible to prevent a decrease in adhesion when connecting the wires 25, thereby enabling the wires 25 to be connected well.

[0064] 7, one reflecting block 30 is provided corresponding to four semiconductor laser units 20. The reflecting block 30 is formed to extend along the X direction and faces the four semiconductor laser units 20 in the Y direction via a collimating lens 40. In this case, the reflecting block 30 reflects the laser light L from the four semiconductor laser units 20 by one reflecting surface 31.

[0065] 7, one collimating lens 40 is provided corresponding to four semiconductor laser units 20. The collimating lens 40 is formed to extend along the X direction and faces the four semiconductor laser units 20 in the Y direction. The collimating lens 40 has four recesses 41, which collimate the laser light L from the four semiconductor laser units 20. In other words, the collimating lens 40 is configured as a collimating lens array in which four recesses 41 (collimating units) corresponding to the four semiconductor laser units 20 are arranged side by side along the X direction.

[0066] In the modified example of FIG. 7 , the bandpass filter 60 is placed on the light-receiving portion 51 (light-receiving surface) of each light-receiving sensor 50. In this example, the bandpass filter 60 is formed in a square shape. Alternatively, the bandpass filter 60 may be formed in a layer on the light-receiving portion 51 of each light-receiving sensor 50. In this case, the bandpass filter 60 may be formed in, for example, a circular shape corresponding to the light-receiving portion 51. Note that, in both the case where the bandpass filter 60 is placed on the light-receiving portion 51 and the case where the bandpass filter 60 is formed in a film, the bandpass filter 60 may be formed in any shape. In the modified example of FIG. 7 , the refractive index of the resin material R disposed between the collimating lens 40 and the semiconductor laser portion 20 is equal to or greater than the refractive index of the active layer of the laser element 22 and equal to or less than the refractive index of the collimating lens 40.

[0067] This modification also allows for the appropriate arrangement of each element, as in the above embodiment. Furthermore, in this modification, one reflecting block 30 reflects laser light from multiple semiconductor laser units 20. In this case, it is sufficient to provide one reflecting block 30 corresponding to the multiple semiconductor laser units 20, and the reflecting block 30 can be easily and accurately fixed to the wiring substrate 10. This effectively prevents heat generated in the semiconductor laser units 20 from affecting the light-receiving sensor 50, and effectively prevents laser light L emitted from the semiconductor laser units 20 toward the side opposite the collimating lens 40 from being detected as stray light by the light-receiving sensor 50. The reflecting block 30 can also block light from outside the light-emitting and receiving module 2 from entering the light-receiving sensor 50.

[0068] In this modification, one collimator lens 40 collimates the laser light L from the plurality of semiconductor laser portions 20. In this case, it is only necessary to provide one collimator lens 40 corresponding to the plurality of semiconductor laser portions 20, and therefore the collimator lens 40 can be easily and accurately fixed to the wiring substrate 10. In addition, the collimator lens 40 can effectively prevent the heat generated in the semiconductor laser portion 20 from affecting the light-receiving sensor 50.

[0069] In the modification of FIG. 7 , the semiconductor laser unit 20 may have a chip-on-board structure, as in the above embodiment. In the modification of FIG. 7 , four reflecting blocks 30 may be provided, as in the above embodiment. In the modification of FIG. 7 , four collimating lenses 40 may be provided, as in the above embodiment. In the modification of FIG. 7 , the bandpass filter 60 may be supported by a pair of supports 16 provided on the main surface 11 so as to sandwich the light-receiving sensor 50, as in the above embodiment. That is, the combination of the configuration of the semiconductor laser unit 20 (chip-on-board structure or laser chip structure), the configuration of the reflecting block 30 (one reflecting block 30 or multiple reflecting blocks 30), the configuration of the collimating lens 40 (one collimating lens 40 or multiple collimating lenses 40), and the configuration of the bandpass filter 60 (one bandpass filter 60, or multiple bandpass filters 60 placed or deposited) is not limited to the above example, and any combination may be used. 7, one reflecting block 30 is provided corresponding to the four semiconductor laser portions 20, but two reflecting blocks 30 may be provided corresponding to the four semiconductor laser portions 20, for example. That is, each reflecting block 30 may correspond to two semiconductor laser portions 20. Similarly, in the modified example of FIG. 7, one collimating lens 40 is provided corresponding to the four semiconductor laser portions 20, but two collimating lenses 40 may be provided corresponding to the four semiconductor laser portions 20, for example. That is, each collimating lens 40 may correspond to two semiconductor laser portions 20.

[0070] The present disclosure is not limited to the above-described embodiments and modifications. For example, the materials and shapes of the components are not limited to those described above, and various materials and shapes can be adopted.

[0071] In the above embodiment, the reflecting block 30 is located between the collimating lens 40 and the light-receiving sensor 50. However, the light-receiving sensor 50 may be located on the opposite side of the semiconductor laser unit 20 from the collimating lens 40. That is, the corresponding light-receiving sensor 50, semiconductor laser unit 20, collimating lens 40, and reflecting block 30 may be arranged in this order in the Y direction. The reflecting block 30 may be a common member with the wiring board 10. For example, the reflecting block 30 may be formed integrally with the wiring board 10 by integral molding. In this case, the reflecting block 30 is formed from the same material as the wiring board 10.

[0072] The reflecting block 30 does not have to have the flat surface 32. For example, the reflecting block 30 may not have the flat surface 32 and may be formed in a triangular shape with the reflecting surface 31 as the hypotenuse when viewed from the X direction. In particular, when the reflecting block 30 is formed integrally with the wiring substrate 10, the reflecting block 30 does not need to be fixed to the wiring substrate 10 by die bonding, and the reflecting block 30 does not need to be adsorbed by a pickup device, so the flat surface 32 can be omitted. Another possible method for picking up the reflecting block 30 is to clamp and lift the reflecting block 30 along the X direction. In this case, the flat surface 32 can also be omitted. The material of the reflecting block 30 is not limited to silicon, and any material may be used.

[0073] Only one semiconductor laser unit 20 may be provided. In this case, one each of a reflection block 30, a collimating lens 40, and a light receiving sensor 50 is also provided. The resin material R arranged between the collimating lens 40 and the semiconductor laser unit 20 may be omitted. The surface 40a of the collimating lens 40 does not need to have a recess 41 formed thereon. The bandpass filter 60 may be omitted. The light emitting and receiving module 2 may be applied to a distance measuring device other than a LiDAR device. The distance measuring device 1 is not limited to a TOF method, and may be a device that measures the distance to the target S using another method such as an FMCW (Frequency Modulated Continuous Wave) method.

[0074] In the above embodiment, the electrodes 13 on the main surface 11 are electrically connected to the electrode pads 14 on the main surface 12 via through holes provided in the wiring substrate 10, but the electrodes 13 may also be electrically connected to the electrode pads 14 via the side surfaces of the wiring substrate 10. In the above embodiment, the six electrodes 29 are grouped into three systems, the anode electrodes 23, the cathode electrodes 24, and the ground electrodes 26, in the electrode pads 14 on the main surface 12, but they may also be grouped into three systems in the electrodes 13 on the main surface 11, or they may also be grouped into three systems inside the wiring substrate 10.

[0075] 1...distance measuring device, 2...light emitting and receiving module (light emitting and receiving module for distance measuring), 3...control unit, 10...wiring board, 11...main surface, 16...support part, 20...semiconductor laser part, 21...submount substrate, 22...laser element (chip), 22a...end face (side face), 30...reflection block, 31...reflection surface, 32...flat surface, 40...collimating lens, 40a...surface, 41...recess, 50...light receiving sensor, 60...bandpass filter, L...laser light, R...resin material, S...target.

Claims

1. A distance measuring light projecting and receiving module comprising: a wiring board having a main surface; a semiconductor laser unit provided on said main surface and emitting laser light from a side surface intersecting said main surface; a reflection block provided on said main surface, the reflection block having a reflection surface inclined with respect to said main surface and reflecting the laser light from the semiconductor laser unit to an opposite side to the wiring board; a collimating lens provided on said main surface and positioned between the semiconductor laser unit and the reflection block; and a light receiving sensor provided on the main surface for detecting the laser light emitted from the semiconductor laser unit, passing through the collimating lens, reflected by the reflection surface of the reflection block, and then reflected by an object.

2. The distance measuring light emitting / receiving module according to claim 1, wherein the reflection block is located between the collimating lens and the light receiving sensor.

3. The distance measuring light emitting / receiving module according to claim 1 or 2, wherein the reflection block is configured as a separate member from the wiring board and is fixed to the main surface.

4. The distance measuring light emitting / receiving module according to any one of claims 1 to 3, wherein the wiring board and the reflective block are formed from different materials.

5. A distance measuring light emitting / receiving module according to any one of claims 1 to 4, wherein the reflection block has a flat surface on the side opposite to the wiring board.

6. A distance measuring light emitting / receiving module as described in any one of claims 1 to 5, wherein the reflective block is formed from reflectively coated silicon.

7. A distance measuring light emitting / receiving module according to any one of claims 1 to 6, comprising a plurality of said semiconductor laser sections.

8. A distance measuring light projecting and receiving module as described in claim 7, comprising a plurality of said reflection blocks, each of said reflection blocks corresponding one-to-one to said semiconductor laser units, and reflecting said laser light from said corresponding semiconductor laser units.

9. The distance measuring light emitting / receiving module according to claim 7, wherein said reflection block reflects said laser light from said plurality of semiconductor laser units.

10. A distance measuring light transmitter / receiver module as described in any one of claims 7 to 9, comprising a plurality of collimating lenses, each of which corresponds one-to-one to a corresponding one of the semiconductor laser sections, and which collimates the laser light from the corresponding semiconductor laser sections.

11. The distance measuring light projecting and receiving module according to any one of claims 7 to 9, wherein the collimating lens collimates the laser light from the plurality of semiconductor laser units.

12. The distance measuring light emitting / receiving module according to any one of claims 1 to 11, wherein a resin material is disposed between the collimating lens and the semiconductor laser portion.

13. A distance measuring light transmitter / receiver module as described in any one of claims 1 to 12, wherein a recess recessed toward the semiconductor laser section is formed on the surface of the collimating lens opposite the semiconductor laser section.

14. A distance measuring light transmitter / receiver module as described in any one of claims 1 to 13, wherein the semiconductor laser section has a submount substrate and a laser element mounted on the submount substrate, and is mounted on the main surface of the wiring board in the submount substrate.

15. A distance measuring light emitting and receiving module as described in any one of claims 1 to 14, further comprising a bandpass filter arranged on the opposite side of the light receiving sensor from the wiring board, the bandpass filter being supported by a pair of supports provided on the main surface so as to sandwich the light receiving sensor therebetween.

16. The distance measuring light emitting / receiving module according to any one of claims 1 to 14, further comprising a layered bandpass filter formed on the light receiving portion of the light receiving sensor.

17. The distance measuring light emitting / receiving module according to any one of claims 1 to 14, further comprising a bandpass filter placed on the light receiving portion of the light receiving sensor.

18. A distance measuring device comprising: a distance measuring light emitting / receiving module according to any one of claims 1 to 17; and a control unit that calculates the distance to the target object based on the detection result of the laser light by the light receiving sensor.

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