JP5240589B2 - Photodetector - Google Patents

Description

  The present invention relates to a light detection device, and more particularly to a light detection device capable of detecting ambient light of a vehicle and raindrops attached to a windshield of the vehicle.

  Conventionally, a light detection device capable of detecting ambient light of a vehicle is known. In addition, a light emitting element capable of emitting infrared rays and a light receiving element that receives infrared rays reflected by the boundary surface between the windshield and the outside of the vehicle out of the infrared rays emitted from the light emitting elements are added to the photodetector. Thus, a light detection device is known that can detect raindrops attached to a windshield in addition to ambient light of a vehicle (see, for example, Patent Document 1).

  In the fourth embodiment of the invention described in Patent Document 1, a transparent transparent portion and a black black portion are provided between two light receiving elements (a first light receiving element and a second light receiving element) and a windshield, and are transparent. The ambient light transmitted through the part is received by the first light receiving element, and the infrared light transmitted through the black part is received by the second light receiving element. In this configuration, the visible light included in the ambient light is blocked by the black portion, thereby suppressing the visible light from reaching the second light receiving element. Thereby, the detection accuracy of raindrops by the second light receiving element is improved.

JP 2006-29807 A

  Since Cited Document 1 describes that “the transparent portion and the black portion are formed by two-color molding or the like so as not to form an air layer or the like therebetween”, the transparent portion and the black portion are described. The joint surface is welded, and it is considered that the vicinity of the joint surface is blotted by melting of the member. If the blurring obstructs the ambient light and infrared light paths in the transparent and black portions, the detection accuracy of the ambient light by the first light receiving element and the detection accuracy of the raindrops by the second light receiving element may be reduced. In addition, when the transparent part and the black part are molded in two colors so that the bleeding in the vicinity of the joint surface is reduced, an advanced manufacturing technique is required. Therefore, the manufacturing cost may increase.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a light detection device that is easy to manufacture and can improve the detection accuracy of ambient light of the vehicle and raindrops attached to the windshield of the vehicle. There is to do.

  The invention described in claim 1 includes a case, a first light guide, a first light receiving element, a light emitting element, a second light guide, and a second light receiving element. The case can be attached to the windshield of the vehicle. The first light guide is housed in a case, and ambient light of the vehicle that has passed through the windshield is incident on the first light guide. The first light receiving element is provided in the case, receives the ambient light transmitted through the first light guide, and outputs a signal corresponding to the intensity of the light. The light emitting element is provided in the case and can emit light. The 2nd light guide is colored so that light of a wavelength of a predetermined range can be shielded. Further, the second light guide is accommodated in the case so as to be positioned between the light emitting element and the windshield in a state where the case is attached to the windshield. Further, the second light guide transmits light emitted from the light emitting element, and light reflected by the boundary surface between the windshield and the outside of the vehicle enters the second light guide. The second light receiving element is provided in the case, receives light that has passed through the second light guide among the light reflected by the boundary surface, and outputs a signal corresponding to the intensity of the light. With this configuration, it is possible to detect ambient light based on the output value of the first light receiving element and to detect raindrops attached to the windshield based on the output value of the second light receiving element. Further, in the above configuration, for example, if the light emitting element emits infrared rays and the second light guide is colored so as to shield visible light, the visible light included in the ambient light is the second light receiving element. The visible light can be blocked by the second light guide so as not to reach. Therefore, the detection accuracy of raindrops by the second light receiving element can be improved.

  Moreover, in this invention, the 1st light guide has the contact surface which can contact a 2nd light guide, and the 1st welding part of protrusion shape in the position different from the said contact surface. The second light guide has a protruding second welded portion at a position corresponding to the first welded portion of the first light guide. And the 1st light guide and the 2nd light guide are united by heat welding the 1st welding part and the 2nd welding part, mutually contacting in the part of the contact surface. As described above, in the present invention, since only the first welded portion and the second welded portion are melted, no bleeding occurs in the vicinity of the contact surface. Thereby, the optical path of the ambient light in the first light guide and the optical path of the light from the light emitting element in the second light guide are not obstructed. Therefore, the detection accuracy of ambient light by the first light receiving element and the detection accuracy of raindrops by the second light receiving element can be improved. Moreover, in this invention, since a 1st light guide and a 2nd light guide can be united only by welding a 1st welding part and a 2nd welding part, manufacture is easy.

  In the invention according to claim 2, the first light guide and the second light guide are formed of the same material. For this reason, it is possible to suppress the play due to the play and stress that may occur between the first light guide and the second light guide due to the difference in the linear expansion coefficient. Thus, the ambient light that passes through the first light guide and the light from the light emitting element that passes through the second light guide are not affected by the play and the deformation, and the first light receiving element and the second light receiving element. Is reachable. Therefore, the detection accuracy of ambient light by the first light receiving element and the detection accuracy of raindrops by the second light receiving element can be further improved.

  According to a third aspect of the present invention, the contact surface of the first light guide and the surface that contacts the contact surface of the second light guide are formed in a tapered shape. Thereby, a 1st light guide can be assembled | attached to a 2nd light guide accurately. Therefore, the detection accuracy of ambient light by the first light receiving element and the detection accuracy of raindrops by the second light receiving element can be further improved.

  According to a fourth aspect of the present invention, the apparatus further includes a substrate that is provided in the case so as to be in contact with the second light guide and on which the first light receiving element, the light emitting element, and the second light receiving element are installed. The substrate has a locking portion at a position corresponding to the first welding portion of the first light guide and the second welding portion of the second light guide, and the locking portion is connected to the first welding portion and the second welding portion. The separation from the second light guide is restricted by being locked by the welded portion with the portion. Therefore, it is not necessary to separately provide a member for fixing the substrate to the second light guide. Therefore, the manufacturing cost can be reduced.

Sectional drawing which shows the photon detection apparatus by 1st Embodiment of this invention. The figure which looked at the photon detection apparatus shown in FIG. 1 from the direction of arrow II. It is a figure which shows the 1st light guide and 2nd light guide of the photon detection apparatus by 1st Embodiment of this invention, Comprising: (A) is the state before welding a 1st welding part and a 2nd welding part. The figure to show, (B) is typical sectional drawing by the BB line of (A), (C) is a figure which shows the state after welding the 1st welding part and the 2nd welding part. It is a figure which shows the 1st light guide, the 2nd light guide, and a board | substrate of the photodetector by 2nd Embodiment of this invention, Comprising: (A) is before welding a 1st welding part and a 2nd welding part. The figure which shows a state, (B) is typical sectional drawing by the BB line of (A), (C) is a figure which shows the state after welding a 1st welding part and a 2nd welding part.

Hereinafter, a plurality of embodiments of the present invention will be described with reference to the drawings. Note that, in a plurality of embodiments, substantially the same components are denoted by the same reference numerals, and description thereof is omitted.
(First embodiment)
1 to 3 show a photodetection device according to a first embodiment of the present invention and a part thereof. The light detection device 10 is attached to the windshield 1 of the vehicle. Here, the windshield 1 is a windshield installed on the front side in the traveling direction of the vehicle. The light detection device 10 is attached in the wiper wiping area of the windshield 1 and above the windshield 1 so as not to obstruct the driver's view. FIG. 1 shows a state in which the light detection device 10 is attached to the windshield 1.

As shown in FIG. 1, the photodetector 10 includes a case 20, a first light guide 30, a first light receiving element 40, a first light receiving element 42, a light emitting element 50, a second light guide 60, and a second light receiving element 70. Etc. The light detection device 10 is used for detecting ambient light of the vehicle and controlling on / off of a vehicle headlight and the like. The light detection device 10 is used for detecting the amount of raindrops attached to the windshield 1 and controlling the wiper wiping mode.
The case 20 is formed in a substantially rectangular parallelepiped shape by a light shielding material made of resin or the like. The case 20 has a bottomed box-like case main body 21 and a plate-like lid member 22. The lid member 22 covers the end of the case body 21 opposite to the bottom (see FIGS. 1 and 2). The bracket 2 is attached to the lid member 22 side of the case 20. The case 20 is attached to the vehicle interior side of the windshield 1 with the adhesive 3 through the bracket 2.

  Here, for the following explanation, an xyz space is defined by showing an x-axis, a y-axis, and a z-axis in FIG. The x-axis indicates the front-rear direction of the vehicle, the y-axis indicates the left-right direction of the vehicle, and the z-axis indicates the vertical direction of the vehicle. That is, the xy plane is a plane that is horizontal with respect to the vehicle (ground), and the z-axis coincides with a straight line in the vertical direction.

  The case 20 has an opening 23 between the case main body 21 and the lid member 22. The windshield 1 to which the case 20 is attached has an inclination angle θ1 with respect to the x axis (horizontal). In a state where the light detection device 10 is attached to the windshield 1, the ambient light of the vehicle can enter the case 20 by passing through the windshield 1 and passing through the opening 23.

  The first light guide 30 is accommodated in the case 20 so as to be disposed in the vicinity of the opening 23. The first light guide 30 is made of, for example, a resin such as polycarbonate or glass, and is transparent. The first light guide 30 has an entrance surface 31 and an exit surface 32. The incident surface 31 is located in the opening 23. Of the ambient light of the vehicle that has passed through the windshield 1, light 6 in a specific direction is incident on the incident surface 31. Here, the “specific direction” is a direction from the front of the vehicle toward the vehicle. That is, the light 6 in the specific direction is light in front of the vehicle and is in a direction that coincides with the x axis. Hereinafter, the light 6 in a specific direction is referred to as the front light 6. The forward light 6 incident on the incident surface 31 passes through the inside of the first light guide 30 and is emitted from the emission surface 32.

  The first light guide 30 has an entrance surface 33 and an exit surface 34 in addition to the entrance surface 31 and the exit surface 32. Of the ambient light of the vehicle that has passed through the windshield 1, the upper light 7 is incident on the incident surface 33. Here, the upward light 7 is light from above the vehicle toward the vehicle, that is, light above the vehicle. The upward light 7 is light in a direction that coincides with the z-axis. The upper light 7 incident on the incident surface 33 is totally reflected at the boundary surface between the inner side and the outer side of the first light guide 30 and changes its optical path. The upper light 7 reflected by the boundary surface of the first light guide 30 is emitted from the emission surface 34.

A substrate 11 is provided inside the case 20. A first light receiving element 40, a first light receiving element 42, a light emitting element 50, a second light receiving element 70, and the like are installed on the substrate 11.
The first light receiving element 40 includes a photodiode or a phototransistor. The first light receiving element 40 is installed at a position where the front light 6 emitted from the emission surface 32 of the first light guide 30 can be received.

  When the first light receiving element 40 receives the front light 6 on the light receiving surface 41, the first light receiving element 40 outputs a signal corresponding to the intensity of the front light 6. In the present embodiment, the first light receiving element 40 is particularly configured to output a signal corresponding to the intensity of visible light. The output signal from the first light receiving element 40 is sent to a signal amplifier (not shown) on the substrate 11, and the signal level is amplified. A signal whose signal level is amplified by the signal amplifier is transmitted as a forward light intensity signal to a control device (not shown) via an arithmetic circuit element (not shown) on the substrate 11 and the connector 12.

  Similar to the first light receiving element 40, the first light receiving element 42 is configured by a photodiode, a phototransistor, or the like. The first light receiving element 42 is installed at a position where the upper light 7 emitted from the emission surface 34 of the first light guide 30 can be received. When the first light receiving element 42 receives the upper light 7 on the light receiving surface 43, the first light receiving element 42 outputs a signal corresponding to the intensity of the upper light 7. In the present embodiment, like the first light receiving element 40, the first light receiving element 42 is configured to output a signal corresponding to the intensity of visible light. The output signal from the first light receiving element 42 is transmitted as an upward light intensity signal to a control device (not shown) via an arithmetic circuit element (not shown) on the substrate 11 and the connector 12. As described above, the first light receiving element 42 receives the ambient light transmitted through the first light guide 30, similarly to the first light receiving element 40.

Based on the intensity signal of the front light transmitted from the first light receiving element 40 and the intensity signal of the upward light transmitted from the first light receiving element 42, the control device controls on / off of the headlight of the vehicle. Do.
In the present embodiment, two light emitting elements 50 are installed on the substrate 11 with the first light receiving element 42 interposed therebetween (see FIG. 2). The light emitting element 50 is configured to be able to emit infrared rays, for example.

  The lid member 22 of the case 20 has a substantially rectangular opening 24 at the center. The second light guide 60 is accommodated in the case 20 so that one surface 61 is exposed from the opening 24. When the light detection device 10 is attached to the windshield 1, a transparent plate-like elastic member 4 is interposed between the second light guide 60 and the windshield 1 between the second light guide 60 and the windshield 1. Provided in contact. The second light guide 60 is positioned between the first light receiving element 40, the first light receiving element 42, and the light emitting element 50 and the windshield 1 in a state where the light detection device 10 is attached to the windshield 1. .

  The second light guide 60 is made of resin such as polycarbonate or glass. Here, the 1st light guide 30 and the 2nd light guide 60 are formed with the same material. Further, the second light guide 60 is colored so as to be able to shield light having a wavelength in a predetermined range. In this embodiment, the 2nd light guide 60 is colored so that the light of the wavelength which belongs to the wavelength range of visible light can be shielded, for example. Therefore, infrared rays can pass through the second light guide 60.

  One second light receiving element 70 is installed at a position approximately the same distance from the two light emitting elements 50 (see FIG. 2). When the second light receiving element 70 receives light on the light receiving surface 71, the second light receiving element 70 outputs a signal corresponding to the intensity of the light. In the present embodiment, the second light receiving element 70 is configured to output a signal corresponding to the intensity of infrared rays.

  As shown in FIG. 1, when the light-emitting element 50 emits infrared rays 8 with the light detection device 10 attached to the windshield 1, the infrared rays 8 are incident on the other surface 62 of the second light guide 60. Then, it is emitted from one surface 61. The infrared rays 8 emitted from one surface 61 of the second light guide 60 are transmitted through the elastic member 4 and reflected by the boundary surface 5 between the windshield 1 and the outside of the vehicle. The infrared rays 8 reflected by the boundary surface 5 pass through the elastic member 4 again, enter the one surface 61 of the second light guide 60, and exit from the other surface 62. The second light receiving element 70 receives the infrared rays 8 emitted from the other surface 62 of the second light guide 60 by the light receiving surface 71. When the second light receiving element 70 receives the infrared ray 8 on the light receiving surface 71, the second light receiving element 70 outputs a signal corresponding to the intensity thereof. An output signal from the second light receiving element 70 is transmitted to an arithmetic circuit element (not shown) on the substrate 11.

  The other surface 62 of the second light guide 60 has the infrared ray 8 reflected from the boundary surface 5 so that the infrared ray 8 irradiated from the light emitting element 50 is efficiently reflected (totally reflected) at the boundary surface 5. Is formed in a lens shape so as to effectively reach the second light receiving element 70.

  When the light emitting element 50 emits infrared rays 8 and raindrops adhere to the outside of the vehicle of the windshield 1, the amount (intensity) of the infrared rays 8 reflected by the boundary surface 5 decreases according to the amount of raindrops. Thereby, the signal output from the 2nd light receiving element 70 changes. Therefore, the arithmetic circuit element to which the output signal from the second light receiving element 70 is transmitted can detect the amount of raindrops attached to the outside of the windshield 1 on the basis of the change in the output signal. A signal related to the detected amount of raindrops is transmitted to a control device (not shown) via the connector 12. The control device controls the wiper wiping mode based on a signal related to the amount of raindrops transmitted from the arithmetic circuit element.

  In the present embodiment, as shown in FIG. 1, the second light guide 60 includes the light emitting element 50, the first light receiving element 40, the first light receiving element 42, and the first light receiving element 50 in a state where the case 20 is attached to the windshield 1. The two light receiving elements 70 and the windshield 1 are provided so as to be positioned. Moreover, the 2nd light guide 60 is colored so that the light of the wavelength which belongs to the wavelength range of visible light can be shielded as mentioned above. Therefore, visible light included in the ambient light of the vehicle is blocked by the second light guide 60 and is prevented from reaching the first light receiving element 40, the first light receiving element 42, and the second light receiving element 70. As a result, the visible light transmitted through the second light guide 60 affects the output values of the first light receiving element 40 and the first light receiving element 42 that receive ambient light in a specific direction, and the light emitting element 50 It is possible to reduce the influence of the output value of the second light receiving element 70 that receives the infrared rays. Therefore, in this embodiment, the detection accuracy of ambient light by the first light receiving element 40 and the first light receiving element 42 and the detection accuracy of raindrops by the second light receiving element 70 can be improved.

Next, the 1st light guide 30 and the 2nd light guide 60 of this embodiment are demonstrated in detail based on FIG.
FIG. 3A is a diagram illustrating the first light guide 30, the second light guide 60, and the connector 12 of the light detection device 10 that is being manufactured. As shown in FIG. 3A, the first light guide 30 is formed in a substantially rectangular plate shape. The second light guide 60 has a bottom portion 63 having a substantially rectangular plate shape. One surface 61 and the other surface 62 shown in FIG. 1 are formed on the bottom 63. Further, the second light guide 60 has a side wall 64 that rises in a rectangular tube shape from the outer edge of the bottom 63 toward the other surface 62. That is, the second light guide 60 is formed in a bottomed box shape. A notch-like fitting portion 65 and a fitting portion 66 are formed in two opposing walls among the four walls constituting the side wall 64 of the second light guide 60. The first light guide 30 is fitted into the fitting portion 65 of the second light guide 60. The connector 12 is fitted in the fitting portion 66.

FIG. 3B schematically shows a cross section taken along line BB in FIG. The 1st light guide 30 has the contact surface 35 which can contact the fitting part 65 of the 2nd light guide 60 in a part of outer edge end. The contact surface 35 is formed on three of the four sides constituting the outer edge of the first light guide 30, and includes a bottom surface 351, a side surface 352, and a side surface 353.
On the other hand, a contact surface 67 that can contact the contact surface 35 of the first light guide 30 is formed in the fitting portion 65 of the second light guide 60. Here, the shape of the fitting portion 65 is a shape corresponding to the shape of the first light guide 35. The contact surface 67 includes a bottom surface 671 that can contact the bottom surface 351 of the first light guide 30, and a side surface 672 and a side surface 673 that can contact the side surface 352 and the side surface 353 of the first light guide 30, respectively.

  In the present embodiment, the side surface 352 and the side surface 353 of the first light guide 30 are formed in a tapered shape so as to approach each other in the direction in which the first light guide 30 is fitted into the second light guide 60. Similarly, the side surface 672 and the side surface 673 of the second light guide 60 are also tapered so as to approach each other in the fitting direction of the first light guide 30.

  In the present embodiment, a groove portion 674 and a groove portion 675 that extend linearly in the fitting direction of the first light guide 30 are formed on the side surface 672 and the side surface 673 of the second light guide 60, respectively. Further, on each of the side surface 352 and the side surface 353 of the first light guide 30, a convex portion 354 and a convex portion 355 extending linearly corresponding to the groove portion 674 and the groove portion 675 are formed (FIG. 3A). reference). As a result, when the first light guide 30 is assembled to the second light guide 60, the convex portions 354 and the convex portions 355 are guided by the groove portions 674 and the groove portions 675 and are fitted into the fitting portions 65. In the state where the first light guide 30 is fitted in the fitting portion 65, the contact surface 35 is in contact with the contact surface 67 of the second light guide 60.

  The first light guide 30 has a protruding first weld 36 at a position different from the contact surface 35. In the present embodiment, two first welds 36 are provided so as to protrude from both ends of the end surface opposite to the bottom surface 351 of the first light guide 30. The second light guide 60 has a protruding second welded portion 68 at a position corresponding to the first welded portion 36 of the first light guide 30. That is, the second welded portion 68 is formed at a position different from the contact surface 67 of the second light guide 60. The number of the second welded portions 68 corresponds to the number of the first welded portions 36, and two second welded portions 68 are provided in the present embodiment.

  As shown in FIG. 3C, the first light guide 30 and the second light guide 60 are in contact with each other at the contact surface 35 and the contact surface 67, and the first weld portion 36 and the second weld portion 68. Are integrated by heat welding. FIG. 3C shows a state after the first welding portion 36 and the second welding portion 68 are thermally welded, and FIGS. 3A and 3B are thermal weldings of the first welding portion 36 and the second welding portion 68. The previous state is shown.

  In the present embodiment, as shown in FIG. 1, the substrate 11 has a surface on which the first light receiving element 40 and the like are installed and an end opposite to the bottom 63 of the side wall 64 of the second light guide 60. It fixes to the 2nd light guide 60 with fixing members, such as a screw which is not illustrated, so that it may touch. As a result, the second light guide 60 is in a state in which the end opposite to the bottom 63 is closed by the substrate 11. In this state, the first light guide 30 and the connector 12 are locked to the substrate 11 to prevent the second light guide 60 from falling off. Further, the substrate 11 is cut out at a portion corresponding to the welded portion M1 so as not to interfere with the welded portion M1 (the portion deformed by welding) between the first welded portion 36 and the second welded portion 68.

The manufacturing method of the photodetection device 10 according to the present embodiment includes the following steps.
(Fitting process)
The first light guide 30 is fitted into the fitting portion 65 of the second light guide 60 (see FIGS. 3A and 3B).
(Thermal welding process)
After the fitting step, the first welding part 36 of the first light guide 30 and the second welding part 68 of the second light guide 60 are thermally welded (see FIG. 3C).
(Board mounting process)
After the heat welding step, the substrate 11 is attached to the second light guide 60 with a fixing member such as a screw.

  As described above, in the present embodiment, the first light guide 30 has the contact surface 35 that can contact the second light guide 60, and the protruding first weld at a position different from the contact surface 35. A portion 36 is provided. The second light guide 60 has a protruding second welded portion 68 at a position corresponding to the first welded portion 36 of the first light guide 30. The first light guide 30 and the second light guide 60 are in contact with each other at the contact surface 35 and the contact surface 67, and the first weld 36 and the second weld 68 are thermally welded. It is united. Thus, in this embodiment, since only the 1st welding part 36 and the 2nd welding part 68 are fuse | melting, a blur does not arise in the vicinity of the contact surface 35 and the contact surface 67. FIG. Thereby, the optical path of the ambient light in the 1st light guide 30 and the optical path of the infrared rays from the light emitting element 50 in the 2nd light guide 60 are not inhibited. Therefore, the detection accuracy of ambient light by the first light receiving element 40 and the first light receiving element 42 and the detection accuracy of raindrops by the second light receiving element 70 can be improved. Moreover, in this embodiment, since the 1st light guide 30 and the 2nd light guide 60 can be united only by welding the 1st welding part 36 and the 2nd welding part 68, manufacture is easy. .

  Moreover, in this embodiment, the 1st light guide 30 and the 2nd light guide 60 are formed with the same material. For this reason, it is possible to suppress the play due to the play and stress that may occur between the first light guide and the second light guide due to the difference in the linear expansion coefficient. Accordingly, the ambient light that passes through the first light guide 30 and the infrared light from the light emitting element 50 that passes through the second light guide 60 are not affected by the backlash and the deformation, and the first light receiving element 40, The first light receiving element 42 and the second light receiving element 70 can be reached. Therefore, the detection accuracy of ambient light by the first light receiving element 40 and the first light receiving element 42 and the detection accuracy of raindrops by the second light receiving element 70 can be further improved.

  Furthermore, in the present embodiment, the side surface 352 and the side surface 353 of the contact surface 35 of the first light guide 30 are tapered so as to approach each other in the direction in which the first light guide 30 is fitted into the second light guide 60. It is formed in a shape. Further, the side surface 672 and the side surface 673 of the second light guide 60 that are in contact with the side surface 352 and the side surface 353 are also tapered so as to approach each other in the fitting direction of the first light guide 30. Thereby, the 1st light guide 30 can be assembled | attached to the 2nd light guide 60 with sufficient precision. Therefore, the detection accuracy of ambient light by the first light receiving element 40 and the first light receiving element 42 and the detection accuracy of raindrops by the second light receiving element 70 can be further improved.

(Second Embodiment)
A part of the photodetecting device according to the second embodiment of the present invention is shown in FIG. The second embodiment is different from the first embodiment in how the second light guide 60 and the substrate 11 are fixed.
In the second embodiment, as illustrated in FIG. 4A, the substrate 11 has positions corresponding to the first welded portion 36 of the first light guide 30 and the second welded portion 68 of the second light guide 60. A locking portion 13 is formed on the top. In the present embodiment, the locking portion 13 is formed by cutting out the substrate 11.

  As shown in FIGS. 4A and 4B, in the state where the substrate 11 blocks the end of the second light guide 60 opposite to the bottom 63, the first welded portion 36 and the second welded portion 68 are provided. Is formed so as to protrude from the substrate 11. In the present embodiment, as shown in FIG. 4C, the first welding of the first light guide 30 is performed in a state where the substrate 11 closes the end of the second light guide 60 opposite to the bottom 63. The portion 36 and the second welded portion 68 of the second light guide 60 are thermally welded. Therefore, the board | substrate 11 has the latching | locking part 13 latched by the welding part M2 (part deform | transformed by welding) of the 1st welding part 36 and the 2nd welding part 68. FIG. Thereby, the separation of the substrate 11 from the second light guide 60 is restricted. In this state, the first light guide 30 and the connector 12 are locked to the substrate 11 to prevent the second light guide 60 from falling off. 4C shows a state after the first welding portion 36 and the second welding portion 68 are thermally welded, and FIGS. 4A and 4B are thermal weldings of the first welding portion 36 and the second welding portion 68. The previous state is shown.

The manufacturing method of the photodetection device according to the present embodiment includes the following steps.
(Fitting process)
The first light guide 30 is fitted into the fitting portion 65 of the second light guide 60.
(Board installation process)
After the fitting step, the substrate 11 is installed at the end of the second light guide 60 opposite to the bottom 63 (see FIGS. 4A and 4B).
(Thermal welding process)
After the substrate installation step, the first weld 36 of the first light guide 30 and the second weld 68 of the second light guide 60 are thermally welded (see FIG. 4C).

  In the present embodiment, a protrusion 69 is formed on the opposite side of the second welded portion 68 of the second light guide 60. A locking portion 14 is formed at a position corresponding to the protruding portion 69 of the substrate 11. The locking portion 14 is formed by cutting out the substrate 11, similarly to the locking portion 13. And the latching | locking part 14 is latched by the projection part 69 which melt | dissolved and deform | transformed with the heat | fever (not shown). Thereby, the effect which regulates detachment | leave of the board | substrate 11 from the 2nd light guide 60 can be improved more.

  As described above, in this embodiment, the substrate 11 has the locking portion 13 at a position corresponding to the first welded portion 36 of the first light guide 30 and the second welded portion 68 of the second light guide 60. Have. As for the board | substrate 11, the detachment | leave from the 2nd light guide 60 is controlled because the latching | locking part 13 is latched by the welding part M2 of the 1st welding part 36 and the 2nd welding part 68. FIG. Therefore, it is not necessary to separately provide a member for fixing the substrate 11 to the second light guide body 60. Therefore, the manufacturing cost can be reduced.

(Other embodiments)
In another embodiment of the present invention, the first light guide and the second light guide may be made of different materials.
Moreover, in other embodiment of this invention, the side surface (contact surface) of a 1st light guide and the side surface (contact surface) of a 2nd light guide do not need to be formed in the taper shape.

  In the above-described embodiment, an example in which the light emitting element is configured to emit infrared rays has been described. On the other hand, in other embodiment of this invention, the light emitting element may be comprised so that the light of wavelengths other than visible light and infrared rays can be inject | emitted. Even in this case, if the second light guide is colored so that visible light can be blocked, the visible light included in the ambient light is blocked by the second light guide, and the light emitted from the light emitting element is the second light guide. And can reach the second light receiving element.

Further, in the above-described embodiment, the example in which the front light and the upper light of the ambient light are received by the two first light receiving elements has been described. On the other hand, in another embodiment of the present invention, one or three or more first light receiving elements may be provided as long as they can receive ambient light.
Moreover, in the above-mentioned embodiment, the example which installs two light emitting elements on a board | substrate was shown. On the other hand, in another embodiment of the present invention, one or three or more light emitting elements may be provided.

In another embodiment of the present invention, the detection result of the ambient light by the light detection device is not limited to the headlight, and may be used to control, for example, the illumination of the instrument of the vehicle or the brightness or on / off of the room light. . Furthermore, the detection result of raindrops by the light detection device may be used not only to control the wiper but also to control a device such as an air conditioner.
Thus, the present invention is not limited to the above-described embodiment, and can be implemented in various forms without departing from the gist thereof.

DESCRIPTION OF SYMBOLS 1 ... Wind shield 5 ... Boundary surface 10 ... Photodetection device 20 ... Case 30 ... 1st light guide 35 ... Contact surface 351 ... Bottom surface (contact surface)
352, 353 ... side surface (contact surface)
36 ... 1st welding part 40, 42 ... 1st light receiving element 50 ... Light emitting element 60 ... 2nd light guide 68 ... 2nd welding part 70 ... 2nd light receiving element

Claims (4)

A case that can be attached to the windshield of the vehicle;
A first light guide that is housed in the case and receives ambient light of the vehicle that has passed through the windshield;
A first light receiving element that is provided in the case, receives the ambient light transmitted through the first light guide, and outputs a signal corresponding to the intensity of the light;
A light emitting element provided in the case and capable of emitting light;
It is colored so as to be able to block light of a wavelength in a predetermined range, and is housed in the case so as to be positioned between the light emitting element and the windshield in a state where the case is attached to the windshield, and is emitted from the light emitting element. A second light guide body through which the reflected light is transmitted and the light reflected by the boundary surface between the windshield and the outside of the vehicle is incident.
A second light receiving element that is provided in the case and receives light transmitted through the second light guide among the light reflected by the boundary surface and outputs a signal corresponding to the intensity of the light. ,
The first light guide has a contact surface that can come into contact with the second light guide, and a protruding first welded portion at a position different from the contact surface,
The second light guide has a protruding second welded portion at a position corresponding to the first welded portion,
The first light guide and the second light guide are brought into contact with each other at the portion of the contact surface, and the first welded portion and the second welded portion are integrated by heat welding. A photodetection device.   The photodetecting device according to claim 1, wherein the first light guide and the second light guide are made of the same material.   3. The photodetector according to claim 1, wherein the contact surface of the first light guide and the surface that contacts the contact surface of the second light guide are formed in a tapered shape. . Further provided in the case so as to contact the second light guide, and further comprising a substrate on which the first light receiving element, the light emitting element, and the second light receiving element are installed,
The substrate has a locking portion at a position corresponding to the first welding portion and the second welding portion, and the locking portion is locked by a welding portion between the first welding portion and the second welding portion. By doing so, detachment from the second light guide is restricted, and the photodetecting device according to any one of claims 1 to 3.

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