Light source device and distance measuring device

Abstract

The present invention relates to a light source device and a distance measuring device. The light source device (7) comprises: a light source chip, a housing (33), a substrate (25), an electromagnetic shielding plate (27) and a heat conducting component (29). The housing accommodates the light source chip. The housing is mounted on the substrate. The electromagnetic shielding plate covers at least a portion of the substrate. The heat conducting component abuts against the housing and the electromagnetic shielding plate.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This international application claims the priority based on Japanese Patent Application No. 2019-11446 filed with the Japan Patent Office on January 25, 2019, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present disclosure relates to a light source device and a distance measuring device. Background Art

[0004] Patent Document 1 discloses a light source device including a light source chip.

[0005] Patent Document 1: Japanese Patent No. 5391753

[0006] As a light source device, there is a device including a light source chip, a housing, and a substrate. The light source chip is housed in the housing. The housing is mounted on the substrate. As a result of a detailed study by the inventors, it was found that the above-mentioned light source device has a problem of difficulty in fully dissipating the heat generated by the light source chip. If the heat generated by the light source chip cannot be fully dissipated, the temperature of the light source chip rises. As a result, the light output of the light source chip decreases, or the light source chip deteriorates. In one aspect of the present disclosure, it is preferred to provide a light source device and a distance measuring device capable of suppressing the temperature rise of the light source chip. Summary of the invention

[0007] One aspect of the present disclosure is a light source device comprising: a light source chip; a housing that accommodates the light source chip; a substrate to which the housing is mounted; an electromagnetic shielding plate that covers at least a portion of the substrate; and a heat conducting member that abuts against the housing and the electromagnetic shielding plate.

[0008] As one aspect of the present disclosure, a light source device has a first heat dissipation path and a second heat dissipation path as heat dissipation paths from the light source chip to the outside of the light source device. The first heat dissipation path is a heat dissipation path that passes through the housing, the heat conduction component, and the electromagnetic shielding plate in sequence. The second heat dissipation path is a heat dissipation path that passes through the housing and the substrate in sequence.

[0009] The light source device as one aspect of the present disclosure includes the first heat dissipation path and the second heat dissipation path, thereby suppressing the temperature rise of the light source chip. As a result, the light source device as one aspect of the present disclosure can suppress the reduction and degradation of the light output of the light source chip. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a block diagram showing the structure of a distance measuring device.

[0011] Figure 2It is an exploded perspective view showing the structure of the light source device.

[0012] Figure 3 yes Figure 2 A cross-sectional view of the light source device at section III-III in FIG.

[0013] Figure 4 It is a top view of the part of the light source unit excluding the metal cover.

[0014] Figure 5 It is a side sectional view of the light source chip driving circuit, the light source unit and the substrate.

[0015] Figure 6 It is an explanatory diagram showing a first heat dissipation path and a second heat dissipation path.

[0016] Figure 7 It is a side sectional view showing the structure of a light source unit in the second embodiment.

[0017] Figure 8 It is a plan view showing the structure of the main body portion in the second embodiment.

[0018] Fig. 9 It is a plan view showing the structure of a casing in the second embodiment. DETAILED DESCRIPTION

[0019] Illustrative embodiments of the present disclosure will be described with reference to the accompanying drawings.

[0020] <First embodiment>

[0021] 1. Structure of Distance Measuring Device 1

[0022] based on Figure 1 The configuration of the distance measuring device 1 will be described. The distance measuring device 1 is mounted on, for example, a vehicle. The distance measuring device 1 measures the distance from the distance measuring device 1 to an object 3. The object 3 is, for example, a target object existing around the vehicle.

[0023] The distance measuring device 1 includes a control unit 5, a light source device 7, an irradiation optical system 9, a light receiving optical system 11, a photodiode (hereinafter referred to as PD) 13, an amplifier 15, and a distance measuring unit 17. The light source device 7 includes a light source chip driving circuit 19 and a light source chip 21.

[0024] The distance measuring device 1 measures the distance from the distance measuring device 1 to the object 3 as follows. The control unit 5 sends a light emission control signal to the light source chip driving circuit 19. The light source chip driving circuit 19 causes the light source chip driving current to flow through the light source chip 21 according to the light emission control signal. When the light source chip driving current flows, the light source chip 21 irradiates the irradiation light 49. The irradiation light 49 reaches the object 3 through the irradiation optical system 9. The wavelength of the irradiation light 49 is, for example, 850 to 950 nm.

[0025] The object 3 reflects the irradiation light 49 to generate reflected light. The reflected light reaches the PD 13 through the light receiving optical system 11. The PD 13 generates a PD output signal based on the reflected light. The amplifier 15 amplifies the PD output signal to generate a light receiving signal. The control unit 5 sends a PD output selection signal to the amplifier 15. The distance measuring unit 17 generates distance measurement data based on the light receiving signal. The control unit 5 receives the distance measurement data. The control unit 5 calculates the distance from the distance measuring device 1 to the object 3 based on the time difference between the time when the light emission control signal is sent and the time when the distance measurement data is received.

[0026] 2. Structure of light source device 7

[0027] based on Figure 2 to Figure 5 The structure of the light source device 7 is described. Figure 2 , Figure 3 As shown, the light source device 7 includes a light source unit 23 , a substrate 25 , an electromagnetic shielding plate 27 , a heat conducting member 29 , and a light source chip driving circuit 19 .

[0028] like Figure 4 , Figure 5 As shown, the light source unit 23 includes a light source chip 21 and a housing 33. The light source chip 21 is, for example, a laser diode.

[0029] The housing 33 accommodates the light source chip 21. Figure 5 As shown, the housing 33 includes: a main body 35, a metal cover 37, an exit window 39, a back electrode pad 40, a plurality of surface electrode pads 45, and a through hole 46. Figure 4 as well as Figure 5 As shown in FIG. 1 , the main body 35 is a box-shaped member made of ceramics. The main body 35 is open at the first opening 41 and the second opening 43 .

[0030] The back electrode pad 40 is formed on a portion of the outer peripheral surface of the main body 35 that is opposite to the substrate 25. A plurality of front electrode pads 45 are formed on the main body 35. Each front electrode pad 45 includes a first portion 45A located outside the main body 35 and a second portion 45B located inside the main body 35. The second portion 45B is connected to the light source chip 21 through a plurality of wires 47. One end of the through hole 46 is connected to the light source chip 21, and the other end of the through hole 46 is connected to the back electrode pad 40.

[0031] The metal cover 37 is a plate-shaped member made of metal. The metal cover 37 closes the first opening 41. The exit window 39 is a plate-shaped member made of transparent glass. The exit window 39 closes the second opening 43. The irradiation light 49 irradiated by the light source chip 21 passes through the exit window 39 toward the Figure 1 The irradiation optical system 9 is shown. The interior of the housing 33 is sealed and filled with an inert gas.

[0032] like Figure 2 As shown, the light source unit 23 and the light source chip driving circuit 19 are mounted on the substrate 25. Figure 5 As shown, the back electrode pad 40 in the light source unit 23 is in contact with the substrate 25 .

[0033] like Figure 5 As shown, the substrate 25 has a conductive layer 51 on its surface. The conductive layer 51 is, for example, grounded. The light source chip driving circuit 19 and the light source chip 21 are electrically connected to the conductive layer 51. The light source chip driving circuit 19 and the first portion 45A are connected through a plurality of wires 53. Therefore, the light source chip driving circuit 19 and the light source chip 21 are electrically connected via the through hole 46, the conductive layer 51, the wire 53, the surface electrode pad 45, and the wire 47.

[0034] The electromagnetic shielding plate 27 is a component made of metal. Figure 2 As shown, the electromagnetic shielding plate 27 includes: a main body 55, a side surface 57 and a flange 58. The main body 55 is a rectangular plate-shaped member. The side surfaces 57 are respectively provided on the four sides of the main body 55. The side surfaces 57 extend in the plate thickness direction of the main body 55. The flange 58 is provided on two side surfaces 57 facing each other. Each flange 58 extends outward from the lower end of the side surface 57. The lower end of the side surface 57 refers to the end of the side surface 57 on the substrate 25 side. The flange 58 abuts against the substrate 25. Holes 60 are respectively formed in the flange 58 and the substrate 25. By passing the fastening portion through the hole 60, the flange 58 is fixed to the substrate 25. The electromagnetic shielding plate 27 shields the noise generated by the light source chip driving circuit 19 and the like.

[0035] like Figure 3 As shown, the main body 55 covers a part of the substrate 25. Covering a part of the substrate 25 means overlapping with a part of the substrate 25 when viewed from the plate thickness direction of the substrate 25. The light source unit 23 and the light source chip driving circuit 19 are mounted on the part of the substrate 25 covered by the main body 55. The light source unit 23 and the light source chip driving circuit 19 are sandwiched between the substrate 25 and the main body 55.

[0036] like Figure 3As shown, the heat conducting member 29 is installed between the light source unit 23 and the main body 55. The heat conducting member 29 abuts against the housing 33 and the main body 55. The heat conducting member 29 abuts against both the metal cover 37 in the housing 33 and the main body 35.

[0037] The heat conducting member 29 may be solid or paste-like. When the heat conducting member 29 is solid, the shape of the heat conducting member 29 is not particularly limited. Examples of the shape of the heat conducting member 29 include a prism shape, a column shape, and a plate shape.

[0038] When the heat-conducting member 29 is solid, examples of the material of the heat-conducting member 29 include silicon, a resin composition containing a heat-conducting filler, and the like. Examples of the heat-conducting filler include ceramic fillers, and the like. When the heat-conducting member 29 is in a paste state, examples of the material of the heat-conducting member 29 include silicone, and the like. Silicone is a synthetic polymer compound having a main skeleton based on a siloxane bond.

[0039] The outer peripheral surface of the heat conducting member 29 is black. The reflectivity of the outer peripheral surface of the heat conducting member 29 to the irradiation light 49 irradiated by the light source chip 21 is 5% or less. For example, when the wavelength of the irradiation light 49 is 850 to 950 nm, the reflectivity of the outer peripheral surface of the heat conducting member 29 to the irradiation light 49 with a wavelength of 850 to 950 nm is 5% or less. Figure 3 As shown, the heat conducting member 29 is located outside the irradiation range 59 of the irradiation light 49. The irradiation range 59 refers to a range irradiated by the irradiation light 49.

[0040] 3. Effects of the light source device 7 and the distance measuring device 1

[0041] (1A) The housing 33 is attached to the substrate 25. In addition, the light source device 7 includes the heat conducting member 29. The heat conducting member 29 is in contact with the housing 33 and the electromagnetic shielding plate 27.

[0042] Therefore, if Figure 3 as well as Figure 6 As shown, the light source device 7 includes a first heat dissipation path 63 and a second heat dissipation path 65 as heat dissipation paths from the light source chip 21 to the outside 61 of the light source device 7. In addition, Figure 6 The P in denoted by represents the amount of heat generated by the light source chip 21 .

[0043] The first heat dissipation path 63 includes a heat dissipation path that passes through the main body 35, the metal cover 37, the heat conduction member 29, and the electromagnetic shielding plate 27 in sequence. In addition, the first heat dissipation path 63 also includes a heat dissipation path that passes through the main body 35, the heat conduction member 29, and the electromagnetic shielding plate 27 in sequence. The second heat dissipation path 65 includes a heat dissipation path that passes through the main body 35, the back electrode pad 40, and the substrate 25 in sequence. In addition, the second heat dissipation path 65 also includes a heat dissipation path that passes through the through hole 46, the back electrode pad 40, and the substrate 25 in sequence.

[0044] The light source device 7 includes the first heat dissipation path 63 and the second heat dissipation path 65, and can suppress a temperature rise of the light source chip 21. As a result, the light source device 7 can suppress a decrease in light output and a lifetime degradation of the light source chip 21.

[0045] (1B) The outer peripheral surface of the heat conducting member 29 is black. Therefore, even if stray light caused by the irradiation light 49 enters the heat conducting member 29, the heat conducting member 29 is unlikely to reflect the stray light. As a result, the stray light in the light source device 7 can be suppressed.

[0046] (1C) The reflectivity of the outer peripheral surface of the heat conducting member 29 to the irradiation light 49 is 5% or less. Therefore, even if stray light caused by the irradiation light 49 enters the heat conducting member 29, the heat conducting member 29 is unlikely to reflect the stray light. As a result, the stray light in the light source device 7 can be suppressed.

[0047] (1D) The heat conducting member 29 is located outside the irradiation range 59. Therefore, it is possible to suppress the heat conducting member 29 from blocking the irradiation light 49.

[0048] (1E) The distance measuring device 1 includes the light source device 7. Therefore, the distance measuring device 1 achieves the effects of (1A) to (1D) described above.

[0049] <Second embodiment>

[0050] 1. Differences from the first embodiment

[0051] The basic structure of the second embodiment is the same as that of the first embodiment, so the differences will be described below. In addition, the same reference numerals as those of the first embodiment represent the same structures, and the previous description is referred to.

[0052] In the first embodiment described above, the surface of the main body 55 that faces the housing 33 is flat. In the first embodiment described above, the surface of the housing 33 that faces the main body 55 is flat. In contrast, in the second embodiment, Figure 7 to Figure 9 As shown in FIG. 1 , the main body 55 is provided with a bank 67 , and the housing 33 is provided with a bank 69 , which is different from the first embodiment.

[0053] The bank 67 is formed on the lower surface 71 of the main body 55 at a position on the irradiation direction A side. The lower surface 71 is the surface of the main body 55 that faces the housing 33. The irradiation direction A is the direction in which the irradiation light 49 travels. The bank 67 protrudes toward the housing 33.

[0054] The bank 69 is formed at a position on the irradiation direction A side of the upper surface 73 of the housing 33. The upper surface 73 refers to the surface of the housing 33 that faces the main body 55. The bank 69 protrudes toward the main body 55. Figure 7 As shown, bank 67 and bank 69 are closer to irradiation range 59 than heat transfer member 29. When heat transfer member 29 attempts to move toward irradiation range 59, it contacts bank 67 and bank 69 and is therefore difficult to move toward irradiation range 59.

[0055] 2. Effects of the light source device 7 and the distance measuring device 1

[0056] According to the second embodiment described in detail above, the effects of the first embodiment described above are achieved, and the following effects are also achieved.

[0057] (2A) The light source device 7 includes the bank 67 and the bank 69. Therefore, it is possible to suppress the heat transfer member 29 from moving in the direction of the irradiation range 59. As a result, the light source device 7 can further suppress the heat transfer member 29 from blocking the irradiation light 49.

[0058] <Other embodiments>

[0059] As mentioned above, although embodiment of this disclosure was described, this disclosure is not limited to the said embodiment, Various deformation|transformation can be made and it can be implemented.

[0060] (1) The material of the main body 35 may be a material other than ceramics. Examples of materials other than ceramics include resins.

[0061] (2) A member made of a material other than metal may be used instead of the metal cover 37. Examples of the material other than metal include resin and the like.

[0062] (3) A part or the whole of the outer peripheral surface of the heat conducting member 29 may not be black. A part or the whole of the outer peripheral surface of the heat conducting member 29 may have a reflectivity of more than 5% for the irradiation light 49 .

[0063] (4) The light source device 7 may be used for purposes other than the distance measuring device 1. Examples of purposes other than the distance measuring device 1 include an image forming device and the like.

[0064] (5) In the second embodiment, the light source device 7 may not include one of the bank 67 and the bank 69. In this case, the light source device 7 can also suppress the movement of the heat transfer member 29 in the irradiation direction A by the bank 67 or the bank 69.

[0065] (6) The heat conducting member 29 may be integrated with the electromagnetic shielding plate 27. The heat conducting member 29 may be a part of the electromagnetic shielding plate 27. The heat conducting member 29 may be integrated with the metal cover 37. The heat conducting member 29 may be a part of the metal cover 37.

[0066] (7) The light source chip driving circuit 19 may also be accommodated inside the housing 33 .

[0067] (8) It is also possible to implement multiple functions of one component in the above-mentioned embodiments by multiple components, or to implement one function of one component by multiple components. In addition, it is also possible to implement multiple functions of multiple components by one component, or to implement one function implemented by multiple components by one component. In addition, it is also possible to omit a part of the structure of the above-mentioned embodiments. In addition, it is also possible to add or replace at least a part of the structure of the above-mentioned embodiments with respect to the structure of other above-mentioned embodiments.

[0068] (9) In addition to the above-mentioned light source device 7, the present disclosure can also be implemented in various ways such as a system with the light source device 7 as a component, a program for making the computer function as the control unit 5, a non-migrating physical recording medium such as a semiconductor memory that records the program, a heat dissipation method of the light source device 7, a heat dissipation structure of the light source device 7, etc.

Claims

1. A light source device, comprising: Light source chip; A housing for accommodating the light source chip; A base plate for mounting the housing; an electromagnetic shielding plate covering at least a portion of the substrate; and The heat conducting component is in contact with the housing and the electromagnetic shielding plate. The heat conducting member is installed between the housing and the electromagnetic shielding plate on the side opposite to the substrate with respect to the housing, but is not arranged on the substrate. At least a portion of the outer peripheral surface of the thermally conductive component is black. The housing is sandwiched between the substrate and the electromagnetic shielding plate. The heat conducting component is located outside the irradiation range of the light irradiated by the light source chip.

2. The light source device according to claim 1, wherein: In at least a portion of an outer peripheral surface of the thermally conductive member, reflectivity of light irradiated by the light source chip is 5% or less.

3. A distance measuring device, A light source device according to claim 1 or 2.

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