JP2014240820A - Photosensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photosensor allowing diagnosis of a light receiving element by suppressing the saturation of an output signal of the light receiving element.SOLUTION: The photosensor includes: a light receiving element 10; a light-emitting element 20; a control part 30 controlling the light receiving element and the light-emitting element, respectively; a mounting part 40 mounting the light receiving element and the light-emitting element respectively thereon; a lid part 50 forming, together with the mounting part, a storage space for storing the light receiving element and the light-emitting element by being fixed to the mounting part; and a reflection part 60 partially reflecting light of the light-emitting element to the light receiving element. The lid part includes a material for transmitting therethrough each of light received by the light receiving element and light emitted by the light-emitting element. In order to suppress saturation of an output signal of the light receiving element due to incidence light, the control part causes the light-emitting element to emit light with the sensitivity of the light receiving element being decreased, and makes light of the light-emitting element reflected by the reflection part partially incident into the light receiving element, thereby performing diagnosis of the light receiving element.

Description

  The present invention includes a light receiving element, a light emitting element, a control unit for controlling each of the light receiving element and the light emitting element, a mounting part for mounting the light receiving element and the light emitting element, and a mounting part together with the light receiving element and the light emitting element. The present invention relates to an optical sensor having a lid portion that constitutes a storage space.

  Conventionally, as shown in Patent Document 1, for example, a photometric device that measures the illuminance level of light to be measured has been proposed. This photometric device includes an optical sensor that converts measured light into an electrical signal, and correction illumination means that irradiates the optical sensor with light. The photometric device also has a calculation control means for detecting the actual sensor output level by sequentially lighting the correction illumination means at a plurality of illuminance levels during correction. The arithmetic control means obtains a correction value of the optical sensor at each illuminance level based on the difference between the sensor output level actually detected at each illuminance level and the sensor output level expected at each illuminance level.

JP 2005-156242 A

  As described above, in the photometric device described in Patent Document 1, the actual sensor output level is detected by sequentially lighting the correction illumination means at a plurality of illuminance levels during correction. However, the light to be measured is incident on the optical sensor in addition to the light emitted from the correcting front means. Therefore, when the illuminance level of the light to be measured is strong, the output signal of the light receiving element may be saturated. When the output signal of the light receiving element is saturated as described above, the sensor output level detected at each illuminance level becomes the same even if the correction illumination means is sequentially turned on at a plurality of illuminance levels. Therefore, there is a possibility that a correction value at each illuminance level cannot be obtained based on the difference between the sensor output level actually detected at each illuminance level and the sensor output level expected at each illuminance level. Furthermore, there is a possibility that even the optical sensor (light receiving element) cannot be diagnosed based on the sensor output level.

  Accordingly, an object of the present invention is to provide an optical sensor capable of diagnosing a light receiving element by suppressing saturation of an output signal of the light receiving element.

  In order to achieve the above object, the present invention controls a light receiving element (10) for converting light into an electric signal, a light emitting element (20) for converting an electric signal into light, and each of the light receiving element and the light emitting element. A control unit (30), a mounting unit (40) for mounting the light receiving element and the light emitting element, and a mounting space for storing the light receiving element and the light emitting element together with the mounting unit by being fixed to the mounting unit. A lid portion (50) that constitutes the light-receiving element, and a reflective portion (60) that reflects part of the light emitted from the light-emitting element to the light-receiving element. The control unit emits the light emitting element with the sensitivity of the light receiving element lowered to suppress saturation of the output signal of the light receiving element due to incident light, and reflects it at the reflecting part. A part of the light from the light emitting element is incident on the light receiving element. In Rukoto, and performs diagnosis of the light receiving element.

  According to this, unlike the configuration in which light is simply incident on the light receiving element from the light emitting element and the light receiving element is diagnosed, saturation of the output signal of the light receiving element (10) due to the incident light is suppressed. Therefore, the light receiving element (10) can be diagnosed.

It is sectional drawing which shows schematic structure of the optical sensor which concerns on 1st Embodiment. It is a block diagram which shows schematic structure of an optical sensor. It is a timing chart for demonstrating the process of a process part. It is a graph which shows the relationship between the energy of the light contained in sunlight, and a wavelength. It is sectional drawing which shows the modification of an optical sensor.

Hereinafter, an embodiment when the present invention is applied to a vehicle will be described with reference to the drawings.
(First embodiment)
The optical sensor according to the present embodiment will be described with reference to FIGS. In the following, the three directions that are orthogonal to each other are referred to as an x direction, a y direction, and a z direction. A plane defined by the x direction and the y direction is referred to as a defined plane. The x direction corresponds to the front-rear direction (traveling / retreating direction) of the vehicle, and the y direction corresponds to the left-right direction of the vehicle.

  As shown in FIGS. 1 and 2, the optical sensor 100 includes a light receiving element 10, a light emitting element 20, a control unit 30, a mounting unit 40, a lid unit 50, and a reflection unit 60. Each of the elements 10, 20, the control unit 30, and the reflection unit 60 is stored in a storage space constituted by the mounting unit 40 and the lid unit 50, and enters the storage space via the lid unit 50. The light is received by the light receiving element 10. A part of the light emitted from the light emitting element 20 is emitted to the outside through the lid part 50, and the remaining light is incident on the light receiving element 10 through the reflecting part 60.

  The optical sensor 100 serves as a solar radiation sensor and a security indicator. The optical sensor 100 calculates the position of the sun by analyzing the output signal of the light receiving element 10 and posts a warning to the user by driving the light emitting element 20 to turn on. In the optical sensor 100 according to the present embodiment, the control unit 30 calculates the sun position and presents a warning to the user.

  The light receiving element 10 converts light into an electric signal, and more specifically is a PD. The back surface of the surface mounted on the mounting portion 40 in the light receiving element 10 is a light receiving surface 10a, and the light receiving surface 10a is along a specified plane. Light incident on the lid 50 and then condensed by the lid 50 is incident on the light receiving surface 10a. Further, a part of the light of the light emitting element 20 reflected by the reflecting portion 60 is also incident on the light receiving surface 10a.

  The light emitting element 20 converts an electrical signal into light, and more specifically is an LED. The back surface of the surface mounted on the mounting portion 40 in the light emitting element 20 is a light emitting surface 20a, and the light emitting surface 20a is along a prescribed plane. A part of the light emitted from the light emitting element 20 is emitted to the outside through the lid part 50, and the remaining light is reflected to the light receiving element 10 by the reflecting part 60. In the present embodiment, as the light emitting element 20, the first light emitting element 21 that irradiates light to the outside of the lid 50 and the light that irradiates light to the reflecting part 60, thereby causing the diagnostic light to enter the light receiving element 10. 2 light emitting elements 22, and light is emitted in a direction away from the mounting portion 40 from the respective light emitting surfaces 21 a and 22 a. The wavelength bands mainly included in the light emitted from each of the light emitting elements 21 and 22 are different, and the wavelength band mainly included in the light emitted from the first light emitting element 21 is a red color that alerts the user or the surrounding people. It is a wavelength band. On the other hand, the wavelength band mainly included in the light emitted by the second light emitting element 22 is a wavelength band that is not so much included in the visible light of sunlight. As shown in FIG. 4, the visible light does not contain much light in the wavelength band near the ultraviolet ray. For this reason, light in the violet or blue wavelength band is emitted from the second light emitting element 22.

  The control unit 30 reduces the sensitivity of the light receiving element 10 in order to suppress saturation of the output signal of the light receiving element 10 due to incident light. Then, the control unit 30 causes the light emitting element 20 to emit light with the sensitivity of the light receiving element 10 lowered, and receives a part of the light of the light emitting element 20 reflected by the reflecting unit 60 (light of the second light emitting element 22). Incidently enter the element 10. By doing so, the control unit 30 detects the output signal of the light receiving element 10 depending on the light emitted from the light emitting element 20 and diagnoses the light receiving element 10.

  As illustrated in FIG. 2, the control unit 30 includes a light emitting unit 31, a discharge unit 32, a sampling unit 33, a storage unit 34, a comparison unit 35, and a diagnosis unit 36. The light emitting unit 31 causes the light emitting element 20 to emit light by passing a current through the light emitting element 20. The discharge unit 32 charges and discharges the charge accumulated in the light receiving element 10. As shown in FIG. 2, the reset switch 32a, the resistor 11, and the light receiving element 10 are connected in series from the power source to the ground. The discharge unit 32 controls the drive (connection) of the reset switch 32a to charge and discharge the charge accumulated in the light receiving element 10. As shown in FIG. 3, the discharge part 32 drives the reset switch 32a in the clear cycle T1. As a result, the charge accumulated in the light receiving element 10 is discharged in the clear period T1, and the charge is accumulated in the light receiving element 10 for a time obtained by removing the pulse width τ1 from the clear period T1.

  The sampling unit 33 samples an output signal based on the charge accumulated in the light receiving element 10 during a sampling period T2 that is shorter than the clear period T1. More specifically, voltages V1 and V2 at the falling edges of two adjacent pulses are detected, and the two voltage differences V2 to V1 are sampled as detection signals. The sampling unit 33 shortens the sampling time T2 described above when diagnosing the light receiving element 10. By doing so, the sensitivity of the light receiving element 10 is lowered, and saturation of the output signal of the light receiving element 10 due to incident light is suppressed. The above-described sampling period T2 corresponds to the predetermined time described in the claims.

  The storage unit 34 stores an expected value that is expected to be output from the light receiving element 10 when the light receiving element 10 is diagnosed. The comparison unit 35 compares the stored value with the output signal (inspection value) of the light receiving element 10 sampled by the sampling unit 33. The diagnosis unit 36 diagnoses the light receiving element 10 based on the comparison result of the comparison unit 35. The diagnosis unit 36 corrects the output signal of the light receiving element 10 based on the comparison value. The diagnosis unit 36 posts a warning to the user by lighting the light emitting element 20 while calculating the position of the sun by analyzing the corrected output signal of the light receiving element 10.

  When the optical sensor 100 is activated, the light emitting unit 31 does not emit light from the light emitting element 20. Therefore, external light that has entered the storage space is incident on the light receiving element 10 via the lid 50. The sampling unit 33 samples the output signal of the light receiving element 10 based on external light and the sampling period T2 as an initial value. The sampled initial value is stored in the storage unit 34 by the comparison unit 35. Next, after the electric charge once accumulated in the light receiving element 20 is discharged by the discharge unit 32, light is emitted from the light emitting element 20. Light from the light emitting element 20 and external light are incident on the light receiving element 10, and the sampling unit 33 uses the output signal of the light receiving element 10 based on the light from the light emitting element 20, the external light, and the sampling period T2 as an inspection value. Sampling. The sampled inspection value is stored in the storage unit 34 by the comparison unit 35. The comparison unit 35 reads the initial value and the inspection value from the storage unit 34, and calculates a value obtained by subtracting the initial value from the inspection value. Then, the comparison unit 35 compares the calculated value with the expected value of the output signal that is expected to be output from the light receiving element 10 when light is emitted from the light emitting element 20. Finally, the diagnosis unit 36 calculates a correction value corresponding to the comparison result of the comparison unit 35, and corrects the output characteristics of the light receiving element 10 with the correction value. As described above, the sampling period T2 is shortened when the light receiving element 10 is diagnosed. Therefore, the above-described inspection value is also reduced. In FIG. 2, the elements of the control unit 30 are divided into blocks, but the other components excluding the sampling unit 33 and the storage unit 34 are elements that are mainly included in the microcomputer.

  The mounting unit 40 mounts the elements 10 and 20 and the control unit 30. The mounting portion 40 is made of an insulating resin, and a lead is insert-molded (not shown). One end of the lead is provided in the storage space, and the other end is exposed to the outside. More specifically, one end of the lead is provided on the mounting surface 30a on which the elements 10, 20 and the control unit 30 are mounted in the mounting portion 40, and the other end of the lead is inserted into a socket (not shown) provided in the vehicle. ing. Each of the elements 10 and 20 and the control unit 30 is electrically connected to the vehicle via the leads.

  The lid part 50 constitutes a storage space together with the mounting part 40. The outer surface of the lid part 50 has a dome shape, and the edge part thereof is fixed to the mounting part 40. Thereby, a storage space is configured by the mounting portion 40 and the lid portion 50.

  The lid 50 is made of a material that transmits light received by the light receiving element 10 and light emitted by the light emitting element 20. A portion (hereinafter, referred to as a first portion 51) corresponding to the light receiving element 10 on the inner surface of the lid 50 has a curved surface shape so that light incident on the lid 50 is condensed on the light receiving element 10. Specifically, the first portion 51 has a curved surface shape that is recessed in the direction from the light receiving element 10 toward the lid portion 50, and has a spherical surface shape. Further, a portion corresponding to the light emitting element 20 on the inner surface of the lid portion 50 (hereinafter, referred to as a second portion 52) emits light emitted from the light emitting element 20 (first light emitting element 21) to the outside of the lid portion 50. It has a curved surface as much as possible. Specifically, the second portion 52 has a curved surface shape that is recessed in a direction from the light emitting element 20 toward the lid portion 50, and has a flat surface shape.

  In the present embodiment, as shown in FIG. 1, each of the first part 51 and the second part 52 forms an independent curved surface and is arranged in the x direction. The optical sensor 100 is mounted on the vehicle such that the first part 51 is located on the traveling direction side of the vehicle and the second part 52 is located on the backward direction side of the vehicle. As the optical sensor 100 is mounted on the vehicle in this way, sunlight that enters the vehicle from the front of the vehicle enters the light receiving element 10.

  In the present embodiment, the light incident on the lid 50 is condensed on the light receiving element 10, and the light emitted from the light emitting element 20 (first light emitting element 21) is diffused outside the lid 50. A difference is provided in the surface roughness of each of the part 51 and the second part 52. That is, the first portion 51 is processed with a surface roughness smoother than that of the second portion 52, and the second portion 52 is processed with a surface roughness rougher than that of the first portion.

  The reflection unit 60 reflects a part of the light from the light emitting element 20 (the light from the second light emitting element 22) to the light receiving element 10. The reflection part 60 is located between the light emitting element 20 and the light receiving element 10 so that the light emitted from the light emitting element 20 and reflected by the reflection part 60 enters the light receiving element 10. The reflection part 60 is made of a material that reflects light emitted from the light emitting element 20, and is formed on the lid part 50. Specifically, the reflecting portion 60 is a film made of a metal material, and the reflecting surface 60 a is inclined with respect to the z direction orthogonal to the light emitting surface 20 a of the light emitting element 20. The inclination of the reflecting surface 60 a is determined so that the light emitted from the light emitting element 20 and reflected by the reflecting surface 60 a is directed toward the light receiving surface 10 a of the light receiving element 10.

  Next, functions and effects of the optical sensor 100 according to the present embodiment will be described. As described above, the control unit 30 causes the light emitting element 20 to emit light with the sensitivity of the light receiving element 10 lowered in order to suppress saturation of the output signal of the light receiving element 10 due to incident light, and is reflected by the reflecting unit 60. The light receiving element 10 is diagnosed by causing a part of the light from the light emitting element 20 (light from the second light emitting element 22) to enter the light receiving element 10. According to this, unlike the configuration in which light is simply incident on the light receiving element from the light emitting element and the light receiving element is diagnosed, saturation of the output signal of the light receiving element 10 due to the incident light is suppressed. Therefore, the light receiving element 10 can be diagnosed. Further, the output signal of the light receiving element 10 can be corrected.

  As the light emitting element 20, a first light emitting element 21 that irradiates light to the outside of the lid 50, and a second light emitting element 22 that makes diagnostic light incident on the light receiving element 10 by irradiating the reflecting part 60 with light. Have. According to this, it is possible to select light suitable for the security indicator and light suitable for diagnosis. That is, as shown in the present embodiment, it is possible to select red light that alerts the user or the surrounding people, or light in a wavelength band that is not mainly included in visible light included in sunlight.

  A first portion 51, which is a curved surface corresponding to the light receiving element 10, and a second portion 52, which is a curved surface corresponding to the light emitting element 20, are formed on the lid 50, and light incident on the lid 50 is incident on the light receiving element 10. Incident light emitted from the light emitting element 20 is emitted to the outside of the lid 50. According to this, in order to condense the light incident on the lid 50 on the light receiving element 10 and emit the light emitted from the light emitting element 20 to the outside of the lid 50, the lid is formed of two different materials. Compared to the configuration, an increase in the type of forming material is suppressed, and an increase in manufacturing cost is suppressed.

  In order to condense the light incident on the lid 50 onto the light receiving element 10 and diffuse the light emitted from the light emitting element 20 to the outside of the lid 50, the first portion 51 is more rough than the second portion 52. Is smooth, and the surface roughness of the second part 52 is rougher than that of the first part. According to this, the light incident on the lid 50 can be condensed on the light receiving element 10 as compared with the configuration in which the first portion has a surface roughness larger than that of the second portion. Further, the light emitted from the light emitting element 20 can be diffused to the outside of the lid portion 50 as compared with the configuration in which the second portion has a smoother surface roughness than the first portion. As a result, the light receiving range of the light receiving element 10 is expanded and the light emitting region of the light emitting element 20 is expanded.

  The first part 51 and the second part 52 are connected to form one curved surface. According to this, the increase in the physique of the cover part 50 is suppressed compared with the structure in which each of the first part and the second part forms an independent curved surface. As a result, an increase in the physique of the optical sensor 100 is suppressed.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

  In this embodiment, the control part 30 of the optical sensor 100 showed the example which calculates a solar position etc. and presents a warning to a user. However, the external device, not the control unit 30, may calculate the sun position or the like based on the output signal of the light receiving element 10, or input an instruction signal for presenting a warning to the user to the control unit 30. You may do it.

  In this embodiment, the example which has the 1st light emitting element 21 and the 2nd light emitting element 22 as the light emitting element 20 was shown. However, as shown in FIG. 5, the optical sensor 100 has one light emitting element 20, a part of the light emitted from the light emitting element 20 is emitted to the outside through the lid part 50, and the remaining light is reflected by the reflecting part. A configuration in which the light is reflected to the light receiving element 10 at 60 can also be adopted.

  In the present embodiment, an example in which light is emitted in the z direction from the light emitting surfaces 20a of the light emitting elements 21 and 22 has been shown. However, the light emission direction is not limited to the above example, and can be changed according to the setting of the optical sensor 100.

  In this embodiment, the example in which the wavelength band mainly contained in the light which each light emitting element 21 and 22 light-emits differs was shown. However, part of the wavelength band may be the same as the light emitted from each of the light emitting elements 21 and 22, or all of the wavelength bands may be the same.

  In the present embodiment, an example in which the diagnosis unit 36 corrects the output signal of the light receiving element 10 is shown. However, the diagnosis unit 36 only diagnoses the output signal of the light receiving element 10 and does not need to correct it.

  The 1st site | part 51 comprised the curved surface shape dented in the direction which goes to the cover part 50 from the light receiving element 10, and showed the example which has comprised the spherical surface shape. However, the curved shape of the first portion 51 is not limited to the above example, and any shape can be used as long as it is a shape that condenses the light incident on the lid 50 on the light receiving element 10.

  The 2nd site | part 52 comprised the curved surface shape recessed in the direction which goes to the cover part 50 from the light emitting element 20, and showed the example which has comprised the surface shape of the oblate ball. However, the curved shape of the second portion 52 is not limited to the above example, and any shape can be adopted as long as it is a shape that emits light emitted from the light emitting element 20 to the outside of the lid 50.

  In the present embodiment, an example in which each of the first part 51 and the second part 52 has an independent curved surface is shown. However, a configuration in which the first portion 51 and the second portion 52 are connected to form a single curved surface may be employed.

  In the present embodiment, an example is shown in which the optical sensor 100 is mounted on the vehicle such that the first part 51 is located on the traveling direction side and the second part 52 is located on the backward direction side. However, the mounting of the optical sensor 100 on the vehicle is not limited to the above example. For example, the optical sensor 100 may be mounted on the vehicle such that the second part 52 is located on the backward direction side and the first part 51 is located on the traveling direction side. As the optical sensor 100 is mounted on the vehicle in this way, sunlight that enters the vehicle from the rear of the vehicle enters the light receiving element 10.

  In this embodiment, the 1st site | part 51 showed the example whose surface roughness is processed more smoothly than the 2nd site | part 52, and the 2nd site | part 52 showed the surface roughness processed rather than the 1st site | part. . However, the surface roughness of each of the first part 51 and the second part 52 need not be particularly processed.

  In this embodiment, the reflection part 60 showed the example which consists of a material which reflects the light emitted from the light emitting element 20. FIG. However, the reflection part 60 may be made of the same material as the lid part 50 and may be a part of the lid part 50. However, in this case, the reflecting portion 60 is inclined with respect to the light traveling direction of the light emitting element 20 so that a part of the light of the light emitting element 20 is reflected by the light receiving element 10, and the surface thereof is mirror-finished. According to this, an increase in the number of parts is suppressed.

DESCRIPTION OF SYMBOLS 10 ... Light receiving element 20 ... Light emitting element 30 ... Control part 40 ... Mounting part 50 ... Cover part 60 ... Reflection part 100 ... Optical sensor

Claims (10)

A light receiving element (10) for converting light into an electrical signal;
A light emitting element (20) for converting an electrical signal into light;
A control unit (30) for controlling each of the light receiving element and the light emitting element;
A mounting portion (40) for mounting the light receiving element and the light emitting element,
A lid portion (50) constituting a storage space for storing the light receiving element and the light emitting element together with the mounting portion by being fixed to the mounting portion,
A reflection part (60) for reflecting a part of the light of the light emitting element to the light receiving element,
The lid portion is made of a material that transmits light received by the light receiving element and light emitted by the light emitting element.
The control unit causes the light emitting element to emit light with reduced sensitivity of the light receiving element to suppress saturation of an output signal of the light receiving element due to incident light, and reflects the light emitting element reflected by the reflecting unit. An optical sensor characterized by diagnosing the light receiving element by causing a part of light to enter the light receiving element. The controller is
A light emitting unit (31) for emitting light from the light emitting element;
A discharge part (32) for discharging the charge accumulated in the light receiving element;
A sampling unit (33) for sampling an output signal based on the electric charge accumulated in the light receiving device after a predetermined time after the electric charge accumulated in the light receiving element is discharged by the discharge unit;
The optical sensor according to claim 1, wherein the sampling unit decreases sensitivity of the light receiving element by shortening the predetermined time when diagnosing the light receiving element. The controller is
A storage unit (34) in which an expected value expected to be output from the light receiving element at the predetermined time at the time of diagnosis of the light receiving element is stored;
A comparison unit (35) for comparing the stored value and an output signal of the light receiving element sampled by the sampling unit;
The optical sensor according to claim 2, further comprising: a diagnosis unit that performs diagnosis of the light receiving element based on a comparison result of the comparison unit.   The optical sensor according to claim 3, wherein the diagnosis unit corrects an output signal of the light receiving element based on the comparison value.   As the light emitting element, a first light emitting element (21) for irradiating light to the outside of the lid portion, and a second light emitting element for irradiating diagnostic light to the light receiving element by irradiating the reflecting portion with light. (22), The optical sensor in any one of Claims 1-4 characterized by the above-mentioned. The wavelength bands mainly included in the light emitted by the first light emitting element (21) and the second light emitting element (22) are different from each other,
The optical sensor according to claim 5, wherein the wavelength band mainly included in the light emitted by the second light emitting element (22) is a wavelength band not mainly included in visible light included in sunlight. A portion (51) corresponding to the light receiving element on the inner surface of the lid portion is a portion (52) corresponding to the light emitting element on the inner surface of the lid portion so as to collect the light incident on the lid portion on the light receiving element. ) Surface roughness is smoother than
The portion corresponding to the light emitting element on the inner surface of the lid portion is more than the portion corresponding to the light receiving element on the inner surface of the lid portion in order to diffuse a part of the light emitted by the light emitting element to the outside of the lid portion. The optical sensor according to claim 1, wherein the surface roughness is also rough.   The optical sensor according to claim 1, wherein the reflection portion is made of a material that reflects light emitted from the light emitting element, and is formed on the lid portion.   The reflection part is a part of the lid part, and is inclined with respect to the light traveling direction of the light emitting element to reflect a part of the light of the light emitting element to the light receiving element, and the surface thereof is mirror-finished The optical sensor according to claim 1, wherein the optical sensor is provided.   2. The reflection part is located between the light emitting element and the light receiving element so that light emitted from the light emitting element and reflected by the reflection part enters the light receiving element. The optical sensor according to any one of 9.

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