Displacement sensor and method for manufacturing displacement sensor

Abstract

This displacement sensor comprises a first member, a second member that is provided on the first member and has an opening, a laser element that is provided on an upper surface of the first member in the opening and emits laser light, a mirror that is provided on a side surface of the opening and reflects the laser light, and a first light detector that receives reflected light resulting from the laser light reflected by the mirror being reflected by an object, wherein the first member and the second member are separate members.

Description

Displacement sensor and method of manufacturing the same

[0001] The present disclosure relates to a displacement sensor and a method for manufacturing a displacement sensor.

[0002] There are known displacement sensors such as optical encoders or Doppler sensors in which a laser beam emitted by a laser element is reflected by a mirror, and the reflected laser beam is reflected by a diffraction grating or a moving object and detected by a photodetector (see, for example, Patent Documents 1 to 3). The member on which the laser element is disposed and the member on which the mirror is disposed are integrated.

[0003] JP-A-5-340719 JP-A-3-291523 JP-A 2005-283487

[0004] In the displacement sensor disclosed in the above patent document, if the member (substrate) on which the laser element is mounted and the member on which the mirror is mounted are integrated, it is difficult to adjust the relative distance between the laser element and the mirror after the laser element is mounted. Therefore, the mounting of the laser element cannot be redone and requires careful attention.

[0005] An object of the present disclosure is to provide a displacement sensor and a method for manufacturing the displacement sensor that allows easy positional adjustment of the distance between a laser element and a mirror even after the laser element is mounted.

[0006] An embodiment of the present disclosure is a displacement sensor comprising: a first member; a second member provided on the first member and having an opening; a laser element provided on an upper surface of the first member within the opening and emitting laser light; a mirror provided on a side surface of the opening and reflecting the laser light; and a first photodetector that receives light reflected by an object from the laser light reflected by the mirror, wherein the first member and the second member are separate members.

[0007] An embodiment of the present disclosure is a method for manufacturing a displacement sensor, including the steps of: preparing a first member having a laser element on an upper surface thereof; and a second member having an opening and a mirror on a side surface of the opening; arranging the second member on the first member so that the laser element is located within the opening; adjusting the position of the second member on the first member by causing the laser element to emit laser light and detecting the laser light reflected by the mirror above the second member; and fixing the second member on the first member at the adjusted position of the second member.

[0008] According to the present disclosure, even after the laser element is mounted, the position of the distance between the laser element and the mirror can be easily adjusted.

[0009] FIG. 1 is a cross-sectional view of a displacement sensor according to a first embodiment. FIG. 2 is a cross-sectional view of a displacement sensor according to the first embodiment. FIG. 3 is a plan view of a first member and a second member of the displacement sensor according to the first embodiment. FIG. 4 is a plan view of the first member of the displacement sensor according to the first embodiment. FIG. 5 is a flowchart showing a manufacturing method of the displacement sensor according to the first embodiment. FIG. 6 is a cross-sectional view showing a manufacturing method of the displacement sensor according to the first embodiment. FIG. 7 is a cross-sectional view showing a manufacturing method of the displacement sensor according to the first embodiment. FIG. 8 is a cross-sectional view showing a manufacturing method of the displacement sensor according to the first embodiment. FIG. 9 is a plan view of a displacement sensor according to a second embodiment. FIG. 10 is a plan view of a displacement sensor according to a third embodiment.

[0010] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The following embodiments are examples for embodying the technical ideas of the invention, and the present disclosure is not limited to the described configurations and numerical values. In each drawing, the same components are denoted by the same reference numerals, and duplicate explanations may be omitted as appropriate.

[0011] (First embodiment) Figures 1 and 2 are cross-sectional views of a displacement sensor according to the first embodiment. Figure 3 is a plan view of a first member and a second member of the displacement sensor according to the first embodiment. Figure 4 is a plan view of the first member of the displacement sensor according to the first embodiment. The stacking direction of the first member 10 and the second member 20 is the Z direction, the direction in which laser light 50A is emitted from the laser element 14 is the X direction, and the direction intersecting the X direction and the Z direction is the Y direction. Figure 1 is a cross-sectional view taken along line A-A in Figures 3 and 4. Figure 2 is a cross-sectional view taken along line B-B in Figures 3 and 4.

[0012] 1 to 4, the displacement sensor 100 according to the first embodiment includes a first member 10, a second member 20, a third member 30, a laser element 14, mirrors 22A to 22D, and a photodetector 34. The second member 20 is provided on the first member 10. The third member 30 is provided on the second member 20.

[0013] Wirings 12A to 12D and alignment mark 13 are provided on the top surface of first member 10. Laser element 14 is mounted on the end of wiring 12A. Bonding wire 16A electrically connects the top surface of laser element 14 to the end of wiring 12B. Thermistor 15 is mounted on the end of wiring 12C. Bonding wire 16B electrically connects the top surface of thermistor 15 to the end of wiring 12D. Alignment mark 13 is a mark that indicates the approximate position where second member 20 will be mounted. The top surface of first member 10 is substantially flat. Note that a flat surface does not mean a strictly flat surface, but allows for unevenness to the extent of manufacturing errors.

[0014] The second member 20 is a frame having an opening 21 that penetrates in the Z direction. The opening 21 has a rectangular planar shape. The opening 21 has side surfaces 21A to 21D. The side surfaces 21A to 21D are inclined so that the top surface of the opening 21 is larger than the bottom surface. Mirrors 22A to 22D are provided on the side surfaces 21A to 21D. The angle (inclination angle θ) formed between the bottom surface of the second member 20 and the side surfaces 21A to 21B is, for example, smaller than 90° and larger than 45°.

[0015] The laser element 14 and thermistor 15 are provided on the upper surface of the first member 10 within the opening 21. Wirings 12A to 12D pass between the first member 10 and the second member 20 and extend from within the opening 21 to the outside of the second member 20. This allows voltage or current to be supplied to the laser element 14 from outside the second member 20 via wirings 12A and 12B. A signal can be output from the thermistor 15 to the outside of the second member 20 via wirings 12C and 12D. The laser element 14 is controlled based on temperature information detected by the thermistor 15. The thermistor 15 is an example of a component provided within the opening 21, and components other than the thermistor 15, such as a control circuit that controls the laser element 14 and a drive circuit that drives the laser element 14, may also be provided within the opening 21.

[0016] The third member 30 has lenses 32A and 32B on its lower surface (-Z surface). The photodetector 34 is provided on the upper surface of the third member 30.

[0017] 1, the intensity distribution of the laser beams 50A and 50B is, for example, a Gaussian distribution. In the laser beams 50A to 53A and 50B to 53B, the center line is the line where the intensity is maximum and corresponds to the optical axis. The two outer lines are lines where the intensity of the laser beam is half of the maximum intensity. The distance between the two outer lines is the full width at half maximum.

[0018] As shown in Figure 1, the laser element 14 emits laser beams 50A and 50B in the +X direction and the -X direction, respectively. The laser beams 50A and 50B are diverging beams. The mirrors 22A and 22B are provided to reflect light within at least the full width at half maximum of the laser beams 50A and 50B. The optical axes of the laser beams 51A and 51B reflected by the mirrors 22A and 22B approach each other as they move in the +Z direction. The mirrors 22A and 22B are flat mirrors. The laser beams 51A and 51B are diverging beams.

[0019] The lenses 32A and 32B are convex lenses that transmit the laser beams 51A and 51B as collimated laser beams 52A and 52B. The lenses 32A and 32B are configured to transmit at least light within the full width at half maximum of the laser beams 51A and 51B. The laser beams 52A and 52B are refracted at the upper surface of the third member 30 and emitted as laser beams 53A and 53B. The laser beams 53A and 53B are collimated beams that approach each other as they move in the +Z direction. Note that the collimated beams do not need to be strictly collimated, as long as they are collimated enough to function as a displacement sensor. An object 36 is located in the +Z direction of the displacement sensor 100. The laser beams 53A and 53B are reflected by the object 36. The photodetector 34 receives reflected light 54A and 54B of the laser light 53A and 53B reflected by the object 36. The photodetector 34 may be two photodetectors, one for receiving the reflected light 54A and the other for receiving the reflected light 54B. When the object 36 is a diffraction grating, the displacement sensor 100 functions as an encoder. When the object 36 is an object other than a diffraction grating, the displacement sensor 100 functions as a Doppler sensor.

[0020] The first member 10 is an insulating substrate such as aluminum nitride, aluminum oxide, or diamond, or a semiconductor substrate such as a silicon substrate. The wiring 12A-12D are metal films such as copper, gold, or aluminum. The second member 20 is a semiconductor substrate such as a silicon substrate, an insulating substrate, or a metal substrate. The mirrors 22A-22D are metal films with high reflectivity at the wavelength of the laser light, such as aluminum, gold, or silver, and are formed on the side surfaces 21A and 21B using, for example, a sputtering method. The third member 30 is a member transparent to the laser light, such as an inorganic insulator such as glass or a transparent resin. The laser element 14 is, for example, a semiconductor laser element, such as a distributed-feedback (DFB) laser. By appropriately setting the reflectivity of the end faces of the laser element 14, laser light 50A and 50B can be emitted from both end faces of the laser element 14. The photodetector 34 is, for example, a photodiode.

[0021] Sides 21C and 21D do not have to be inclined, but they may be inclined when side surfaces 21A and 21B are inclined. Also, mirrors 22C and 22D do not have to be provided, but they may be formed when mirrors 22A and 22B are formed. When a single-crystal silicon substrate having a (100) plane as the main surface is used as the second member 20, if opening 21 is formed using an etching method using a potassium hydroxide aqueous solution or the like, side surfaces 21A and 21B become (111) planes. In this case, the inclination angle θ is 54.7°. When opening 21 is formed in this manner, the inclination angles of side surfaces 21C and 21D are also 54.7°. Furthermore, the planar shape of opening 21 is rectangular.

[0022] FIG. 5 is a flowchart illustrating a method for manufacturing a displacement sensor according to the first embodiment. As shown in FIG. 5, a first member 10, a second member 20, and a third member 30 are prepared (step S10). Wiring 12A-12D is formed on the top surface of the first member 10. An opening 21 is formed in the second member 20, and mirrors 22A-22D are formed on the side surfaces 21A-21D. Lenses 32A and 32B are formed on the bottom surface of the third member 30. Next, a laser element 14 is mounted on the top surface of the first member 10 (step S11). As shown in FIG. 3, the top surface of the laser element 14 and the wiring 12B are electrically connected using bonding wire 16A. A pedestal may be mounted on the first member 10, and the laser element 14 may be mounted on the pedestal.

[0023] Next, the second member 20 is placed on the first member 10 and the position of the second member 20 is adjusted (step S12). FIG. 6 is a cross-sectional view showing a manufacturing method of the displacement sensor according to the first embodiment. As shown in FIG. 6, the second member 20 is placed on the first member 10 so that the laser element 14 is positioned within the opening 21 and the four corners of the second member 20 are aligned with the alignment marks 13 shown in FIG. 4. A camera 38 capable of capturing two-dimensional images is placed above the laser element 14. The camera 38 captures light of the wavelengths of the laser beams 50A and 50B. If the laser beams 50A and 50B are infrared light, the camera 38 is an infrared camera. The distance between the camera 38 and the first member 10 is set to a predetermined distance. In this state, the laser element 14 emits the laser beams 50A and 50B in the ±X directions. The laser beams 50A and 50B are reflected by mirrors 22A and 22B. The reflected laser beams 51A and 51B reach the imaging surface of the camera 38.

[0024] The position of the second member 20 in the X direction is adjusted using the jig 28 so that the positions of the laser beams 50A and 50B are at predetermined positions in the image captured by the camera 38. For example, the position of the second member 20 in the X direction is adjusted so that a distance D2A between the position where the laser beam 51A is irradiated onto the camera 38 and the center line 39 is equal to a distance D2B between the position where the laser beam 51B is irradiated onto the camera 38 and the center line 39. This makes the distance D1A between the laser element 14 and the mirror 22A equal to the distance D1B between the laser element 14 and the mirror 22B.

[0025] 5 , the second member 20 is fixed to the first member 10 at the position adjusted in step S12 (step S13). For example, an adhesive is used to fix the second member 20. Next, the third member 30 is fixed onto the second member 20 (step S14). The photodetector 34 is mounted on the third member 30. The photodetector 34 may be mounted on the third member 30 in advance. In this manner, the displacement sensor 100 according to the first embodiment is manufactured.

[0026] In the displacement sensor 100, it is important to adjust the distances over which the laser beams 50A, 51A, 52A, and 53A propagate from the laser element 14 to the target object 36. In particular, when the laser beams 53A and 53B interfere with each other, it is important to adjust the distances over which the laser beams 50A, 51A, 52A, and 53A propagate and the distances over which the laser beams 50B, 51B, 52B, and 53B propagate. For example, to make the distances over which the laser beams 50A, 51A, 52A, and 53A propagate equal to the distances over which the laser beams 50B, 51B, 52B, and 53B propagate, the distances D1A and D1B are made equal.

[0027] When the first member 10 and the second member 20 are integrally provided, the mounting position of the laser element 14 is moved in the X direction to adjust the distances D1A and D1B. However, to adjust the position of the laser element 14 while the laser element 14 is emitting the laser beams 50A and 50B, the position of the laser element 14 must be adjusted while supplying a voltage or current to the laser element 14. Furthermore, the position of the laser element 14 must be adjusted by inserting a jig into the opening 21. This makes it difficult to adjust the distances D1A and D1B. In the first embodiment, the distances D1A and D1B can be easily adjusted as shown in FIG. 6 .

[0028] 7 is a plan view of the displacement sensor according to the first embodiment. As shown in FIG. 7, distances D1A and D1B can be adjusted in step S12 of FIG. 5. For example, when distance D1B is to be made longer than distance D1A, distance D1B can be made longer than distance D1A by moving second member 20 in the −Y direction as indicated by arrow 41.

[0029] Fig. 8 is a plan view of the displacement sensor according to the first embodiment. As shown in Fig. 8, in step S12 of Fig. 5, if there is an abnormality in the points 43A and 43B where the laser beams 50A and 50B are irradiated on the mirrors 22A and 22B, the second member 20 is moved in the +X direction as shown by the arrow 42. This makes it possible to shift the points where the laser beams 50A and 50B are irradiated on the mirrors 22A and 22B.

[0030] As described above, according to the first embodiment, the first member 10 and the second member 20 are separate members. As shown in step S10 of FIG. 5 , a first member 10 having a laser element 14 provided on its upper surface and a second member 20 having mirrors 22A and 22B provided on side surfaces 21A and 21B of an opening 21 are prepared. As shown in step S11, the second member 20 is placed on the first member 10 so that the laser element 14 is positioned within the opening 21. As shown in step S12 and FIG. 6 , the laser element 14 is caused to emit laser beams 50A and 50B, and the laser beams 51A and 51B reflected by the mirrors 22A and 22B are detected above the second member 20, thereby adjusting the position of the second member 20 on the first member 10. As shown in step S13, the second member 20 is fixed to the first member 10 at the adjusted position. 6 , by using a jig 28 to press the outer surface of the second member 20, it is possible to easily adjust the position of the second member 20 in the X direction. Also, it is not necessary to adjust the position of the laser element 14 on the upper surface of the first member 10. This makes it easy to emit laser beams 50A and 50B from the laser element 14.

[0031] The laser element 14 emits a pair of laser beams 50A and 50B in opposite directions. A pair of mirrors 22A and 22B are provided corresponding to the pair of laser beams 50A and 50B. The photodetector 34 (first photodetector) receives a pair of reflected beams 54A and 54B formed when the pair of laser beams 53A and 53B are reflected by the pair of mirrors 22A and 22B and then reflected by the object 36. In this displacement sensor 100, adjusting the phase of the laser beams 53A and 53B is important to cause interference between the reflected beams 54A and 54B. Therefore, the first member 10 and the second member 20 are separate members, and the distances D1A and D1B can be accurately adjusted by adjusting the position of the second member 20 on the first member 10.

[0032] The intensity ratio between the laser beams 50A and 50B may be 1:1 or may be different from 1:1. The intensity ratio between the laser beams 50A and 50B may be within a range in which the reflected beams 54A and 54B can interfere with each other. The laser element 14 may emit the laser beam 50A but not the laser beam 50B, and the mirror 22B and the lens 32B may not be provided. For example, a configuration such as that described in Patent Document 1 may be used.

[0033] In order to cause the reflected beams 54A and 54B to interfere with each other, it is preferable that the distance D1A between the laser element 14 and one mirror 22A and the distance D1B between the laser element 14 and the other mirror 22B are equal. The distances D1A and D1B being equal does not mean that they are strictly equal. It is sufficient that the distances D1A and D1B are equal to the extent that the reflected beams 54A and 54B interfere with each other, and the difference between the distances D1A and D1B is preferably equal to or less than the wavelengths of the laser beams 50A and 50B in air, for example.

[0034] When the first member 10 and the second member 20 are integral, the wirings 12A to 12D are provided on the side and top surfaces of the second member 20. In this case, it becomes difficult to form the wirings 12A to 12D, for example, to form the wirings 12A to 12D in areas other than the mirrors 22A and 22B, or to form the wirings 12A to 12D continuously on the top and side surfaces. In the first embodiment, the first member 10 and the second member 20 are separate members. The wirings 12A to 12D are provided on the top surface of the first member 10, connect the inside of the opening 21 with the outside of the second member 20, and pass between the first member 10 and the second member 20. This makes it easy to form the wirings 12A to 12D.

[0035] The wirings 12A and 12B are electrically connected to the laser element 14. This allows a voltage or current to be supplied to the laser element 14 via the wirings 12A and 12B.

[0036] The material of the second member 20 may be selected to precisely control the inclination angle θ of the side surfaces 21A and 21B. For example, by using a silicon substrate with a (100) principal surface as the second member 20, the inclination angle of the side surfaces 21A and 21B can be precisely set to 54.7°. When the first member 10 and the second member 20 are an integral silicon substrate, an insulating film is formed between the silicon substrate and the wirings 12A to 12D to electrically insulate them from each other. However, insulating films have lower thermal conductivity than silicon substrates and may affect the heat dissipation of the laser element 14. Therefore, by using a material with high insulating properties and high thermal conductivity for the first member 10, the wirings 12A to 12D can be electrically insulated from each other without forming an insulating film. This improves heat dissipation from the laser element 14.

[0037] When a material with low thermal conductivity is used for the second member 20, the first member 10 is used which has a thermal conductivity higher than that of the second member 20. This allows the heat generated in the laser element 14 to be efficiently dissipated. The thermal conductivity of the first member 10 is preferably 1.1 times or more, more preferably 1.2 times or more, the thermal conductivity of the second member 20.

[0038] The lenses 32A and 32B are provided on the second member 20, and the laser beams 52A and 52B reflected by the mirrors 22A and 22B are incident on the lenses 32A and 32B. The laser beams 53A and 53B transmitted through the lenses 32A and 32B are irradiated onto the object 36. This allows the object 36 to be irradiated with collimated light.

[0039] Second Embodiment FIG. 9 is a plan view of a displacement sensor according to a second embodiment. The third member 30 is not shown in FIG. 9 . As shown in FIG. 9 , in a displacement sensor 102 according to the second embodiment, the second member 20 has a rectangular planar shape with one side missing. The opening 21 is open in the +Y direction. That is, the second member 20 has portions 23A, 23B, and 23D. The portions 23A and 23B have side surfaces 21A and 21B, respectively. The portion 23D is a portion connecting the pair of side surfaces 21A and 21B of the opening 21. The second member 20 is not provided in a region 44 of the opening 21 facing the portion 23D. The other configurations are the same as those of the first embodiment, and description thereof will be omitted.

[0040] According to the second embodiment, the second member 20 can be placed at a desired position on the first member 10 by sliding the second member 20 in the +Y direction as indicated by the arrow 40. Therefore, when the second member 20 is placed on the first member 10, it is possible to reduce contact of the second member 20 with the laser element 14, thermistor 15, and bonding wire 16A or 16B.

[0041] Third Embodiment FIG. 10 is a plan view of a displacement sensor according to a third embodiment. In FIG. 10, the third member 30 is not shown. As shown in FIG. 10, in a displacement sensor 104 according to the third embodiment, the second member 20 has portions 23A to 23C. The portion 23C is a portion that connects a pair of side surfaces 21A and 21B of the opening 21. The second member 20 is not provided in a region 44 of the opening 21 that faces the portion 23C. As a result, by sliding the second member 20 in the −Y direction as indicated by the arrow 40, the second member 20 can be positioned at a desired position on the first member 10.

[0042] In addition to the wirings 12A to 12D, wirings 12E and 12F are provided on the top surface of the first member 10. A photodetector 17 (second photodetector) is mounted on the end of the wiring 12E on the top surface of the first member 10 in region 44. A bonding wire 16C electrically connects the top surface of the photodetector 17 to the end of the wiring 12F. The wirings 12E and 12F extend through part of region 44. This allows a signal from the photodetector 17 to be output via the wirings 12E and 12F. Laser beams 50A and 50B scattered by the members are incident on the light-receiving surface of the photodetector 17. A control circuit controls the output of the laser element 14 based on the output of the photodetector 17. The other configurations are the same as those in the second embodiment, and therefore description thereof will be omitted.

[0043] According to the third embodiment, the second member 20 can be placed at a desired position on the first member 10 by sliding the second member 20 in the -Y direction as indicated by arrow 40. Furthermore, components such as the photodetector 17 may be mounted in region 44. The components mounted in region 44 may be a thermistor, a drive circuit, or a control circuit in addition to the photodetector 17. In this way, by mounting components on the top surface of the first member 10 in region 44, the displacement sensor 104 can be made smaller.

[0044] In order to monitor the laser light of the laser element 14, it is common to monitor the laser light emitted from the surface opposite to the laser light emission surface. However, when laser light 50A and 50B are emitted from both end surfaces of the laser element 14, it is not possible to monitor one of the laser lights. According to the third embodiment, the photodetector 17 is provided in the region 44 to detect part of the laser light. This makes it possible to provide a monitoring photodetector 17 for controlling the laser element 14. The photodetector 17 may also be provided in the region 44 of the displacement sensor 102 of the second embodiment.

[0045] Although the embodiments have been described above, they are presented as examples and the present invention is not limited to the above embodiments. The above embodiments can be implemented in various other forms, and various combinations, omissions, substitutions, modifications, etc. can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as set forth in the claims.

[0046] Note that aspects of the present invention are as follows, for example. <1> A displacement sensor including a first member, a second member provided on the first member and having an opening, a laser element provided on an upper surface of the first member within the opening and emitting laser light, a mirror provided on a side surface of the opening and reflecting the laser light, and a first photodetector receiving light reflected by an object from the laser light reflected by the mirror, wherein the first member and the second member are separate members. <2> The displacement sensor described in <2>, wherein the laser element emits a pair of laser light beams in opposite directions, a pair of mirrors are provided corresponding to the pair of laser light beams, and the first photodetector receives a pair of reflected light beams reflected by the object from the pair of laser light beams reflected by the pair of mirrors. <3> The displacement sensor described in <2>, wherein the second member has a portion connecting the pair of side surfaces of the opening where the pair of mirrors are provided, and the second member is not provided in a region of the opening facing the portion. <3> The displacement sensor according to <3>, further comprising a component provided on the upper surface of the first member in the region. <5> The displacement sensor according to <4>, wherein the component is a second photodetector. <6> The displacement sensor according to any one of <2> to <5>, wherein the distance between the laser element and one of the pair of mirrors is equal to the distance between the laser element and the other of the pair of mirrors. <7> The displacement sensor according to any one of <1> to <6>, further comprising wiring provided on the upper surface of the first member, connecting the inside of the opening to the outside of the second member, and passing between the first member and the second member. <8> The displacement sensor according to <7>, wherein the wiring is electrically connected to the laser element. <9> The displacement sensor according to any one of <1> to <8>, wherein the thermal conductivity of the first member is higher than the thermal conductivity of the second member. <10> The displacement sensor according to any one of <1> to <9>, further comprising: a lens provided on the second member, onto which the laser light reflected by the mirror is incident; and the laser light transmitted through the lens is irradiated onto the object.<11> A method for manufacturing a displacement sensor, comprising: preparing a first member having a laser element provided on an upper surface thereof; and a second member having an opening and a mirror provided on a side surface of the opening; arranging the second member on the first member so that the laser element is located within the opening; adjusting a position of the second member on the first member by causing the laser element to emit laser light and detecting the laser light reflected by the mirror above the second member; and fixing the second member on the first member at the adjusted position of the second member.

[0047] This application claims priority based on Japanese Patent Application No. 2024-152536, filed on September 4, 2024, the entire contents of which are incorporated herein by reference.

[0048] 10 First member 12A, 12B, 12C, 12D, 12E, 12F Wiring 14 Laser element 15 Thermistor 16A, 16B, 16C Bonding wire 17, 34 Photodetector 20 Second member 21 Opening 21A, 21B, 21C, 21D Side surface 22A, 22B, 22C, 22D Mirror 23A, 23B, 23C, 23D Part 28 Jig 30 Third member 32A, 32B Lens 36 Object 38 Camera 44 Area 50A, 50B, 51A, 51B, 51A, 52B, 53A, 53B Laser light 54A, 54B Reflected light

Claims

1. A displacement sensor comprising: a first member; a second member provided on the first member and having an opening; a laser element provided on the upper surface of the first member within the opening and emitting laser light; a mirror provided on the side of the opening and reflecting the laser light; and a first photodetector that receives light reflected by the mirror and then reflected by an object, wherein the first member and the second member are separate members.

2. A displacement sensor as described in claim 1, wherein the laser element emits a pair of laser beams in opposite directions, the mirrors are provided in pairs corresponding to the pair of laser beams, and the first photodetector receives a pair of reflected beams formed when the pair of laser beams is reflected by the pair of mirrors and then reflected by the object.

3. A displacement sensor as described in claim 2, wherein the second member has a portion connecting a pair of side surfaces of the opening where the pair of mirrors are provided, and the second member is not provided in an area of ​​the opening facing the portion.

4. The displacement sensor according to claim 3, further comprising a component provided on the upper surface of said first member in said region.

5. The displacement sensor of claim 4, wherein the component is a second photodetector.

6. A displacement sensor according to any one of claims 2 to 5, wherein the distance between the laser element and one of the pair of mirrors is equal to the distance between the laser element and the other of the pair of mirrors.

7. A displacement sensor as described in any one of claims 1 to 5, comprising wiring provided on the upper surface of the first member, connecting the inside of the opening to the outside of the second member, and passing between the first member and the second member.

8. The displacement sensor according to claim 7, wherein the wiring is electrically connected to the laser element.

9. A displacement sensor according to any one of claims 1 to 5, wherein the thermal conductivity of the first member is higher than the thermal conductivity of the second member.

10. A displacement sensor according to any one of claims 1 to 5, further comprising a lens provided on the second member onto which the laser light reflected by the mirror is incident, and the laser light transmitted through the lens is irradiated onto the object.

11. A method for manufacturing a displacement sensor, comprising the steps of: preparing a first member having a laser element on its upper surface; and a second member having an opening and a mirror on a side of the opening; arranging the second member on the first member so that the laser element is located within the opening; adjusting the position of the second member on the first member by causing the laser element to emit laser light and detecting the laser light reflected by the mirror above the second member; and fixing the second member on the first member at the adjusted position of the second member.

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