JP2016072574A - Light sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light sensor that makes it possible for light from a light emitting diode to be uniformly seen regardless of a viewing direction with respect to a filter.SOLUTION: In a filter 140, a crimping process is provided on both an internal surface 142 and an external surface 143. On the internal surface 142 of the filter 140, the roughness of the crimping process in the inside area 144 of the internal surface 142 is greater than that of the crimping process in a peripheral area 145 surrounding the inside area 144. Similarly, on the external surface 143 of the filter 140, the roughness of the crimping process in the inside area 146 of the internal surface 143 is greater than that of the crimping process in a peripheral area 147 surrounding the inside area 146. Thus, the respective inside areas 144, 146 of the surfaces 142, 143 of the filter 140 are made less likely to be subjected to scatter of light from a light emitting diode 130 than peripheral areas 145, 147.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a light sensor including a light emitting diode (LED).

  Conventionally, for example, Patent Literature 1 proposes a light sensor including a sensor chip in which a light receiving portion is formed. Further, a configuration in which the sensor chip is mounted on the sensor housing and covered with a filter attached to the sensor housing has been proposed.

  The filter serves as a cover that covers the sensor chip. Such a filter has a recess formed in the center of the inner peripheral surface. Since the thickness of the filter is different due to the concave portion, the light incident on the filter is condensed on the light receiving portion of the sensor chip. That is, the filter functions as a lens.

Japanese Patent No. 4604301

  Here, the structure which mounts a light emitting diode (LED) in a sensor housing can be considered. The light of the light emitting diode is transmitted to the outside through the filter. Thereby, since the light of a light emitting diode is visually recognized, it becomes possible to use a light sensor as an indicator.

  However, in the above-described conventional technology, the thickness of the filter is adjusted so that external light is condensed on the sensor chip. Therefore, the light intensity of the light-emitting diode is generated by the difference in the filter thickness. Therefore, it is conceivable to apply a uniform texture on the surface of the filter, but there is a problem that the light emission diameter, light emission position, and number of light emission points of the light emitting diodes appear different depending on the viewing direction with respect to the filter. That is, there is a problem that the light appearance of the light emitting diodes varies depending on the viewing direction with respect to the filter.

  An object of this invention is to provide the light sensor which can make the light of a light emitting diode appear uniformly irrespective of the visual recognition direction with respect to a filter in view of the said point.

  In order to achieve the above object, the invention according to claim 1 includes a holder (110) having a pedestal (111). Also, a sensor chip that is disposed on the pedestal part (111), has a light receiving part (121) that detects the intensity of light, and acquires a sensor signal based on the intensity of external light received by the light receiving part (121). (120).

  Further, the lens unit (141) disposed on the pedestal unit (111) is provided with a light emitting diode (130) that emits light according to a light emission command, has a hemispherical shell shape, and collects external light on the light receiving unit (121). And a filter (140) assembled to the holder (110) so as to cover the pedestal (111).

  The filter (140) is subjected to a graining process on one or both of the inner surface (142) on the holder (110) side and the outer surface (143) opposite to the inner surface (142). And the roughness of the embossing in the inner area (144, 146) of the embossed surface (142, 143) of the inner surface (142) and the outer surface (143) is the inner area (144, 146). It is characterized in that it is rougher than the roughness of the embossing in the peripheral region (145, 147) surrounding the.

  According to this, since the scattering of light in the inner region (144, 146) is smaller than the peripheral region (145, 147) of the respective surfaces (142, 143) of the filter (140), the peripheral region (145, 147) The intensity of light in the inner region (144, 146) can be increased. That is, the contrast of light between the inner region (144, 146) and the peripheral region (145, 147) can be increased. Therefore, the light of the light emitting diode (130) can be made to appear uniform regardless of the viewing direction with respect to the filter (140).

  In addition, the code | symbol in the bracket | parenthesis of each means described in this column and the claim shows the correspondence with the specific means as described in embodiment mentioned later.

It is sectional drawing of the light sensor which concerns on 1st Embodiment of this invention. It is the top view which looked at the filter to the base side. (A) is the schematic diagram which showed the scattering of the light in the peripheral area | region where the fine embossing process was performed, (b) is the schematic diagram which showed the scattering of the light in the inner area | region where the rough embossing process was performed. is there. It is the top view which showed typically the difference in the light intensity of a light emitting diode. It is sectional drawing of the light sensor which concerns on 2nd Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the same or equivalent parts are denoted by the same reference numerals in the drawings.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. The light sensor according to this embodiment is mounted on a vehicle, for example, and is used as a solar radiation sensor that is used for automatic turning on / off of an automobile taillight or headlight, control of a car air conditioner, and the like.

  As shown in FIG. 1, the light sensor 100 includes a holder 110, a sensor chip 120, a light emitting diode 130, and a filter 140.

  The holder 110 is a columnar component for housing the sensor chip 120, the light emitting diode 130, and other wirings. The holder 110 is configured by molding a resin material, for example. The holder 110 is insert-molded with a terminal (not shown) for electrical connection with the outside.

  The holder 110 has a pedestal 111. The pedestal portion 111 is a planar portion provided at the end of the holder 110 and is a portion on which the sensor chip 120 and the light emitting diode 130 are mounted. The pedestal 111 has a stepped shape, has a recess, or can be changed in shape as necessary.

  On the other hand, the opposite side of the holder 110 from the pedestal 111 is formed in a connector shape. And the connector part of the holder 110 is fixed to the fixation object of a vehicle, and is electrically connected to ECU (Electrical Control Unit) via a harness.

  The sensor chip 120 is configured as a plate-like IC chip, and is disposed on the pedestal 111 of the holder 110. In order to ensure the characteristics of the sensor chip 120, the sensor chip 120 is fixed to the pedestal part 111 so as to be positioned at the center (on the central axis) of the holder 110 on the installation surface of the pedestal part 111 of the holder 110. In addition, the sensor chip 120 includes a light receiving unit 121 that detects the intensity of received light. The light receiving unit 121 is configured as a photodiode.

  Specifically, the sensor chip 120 is composed of, for example, an n-type silicon substrate, and a p-type region is formed in the surface layer portion of the n-type silicon substrate. A cathode electrode is formed on the back surface of the n-type silicon substrate, and an anode electrode (not shown) is provided in each p-type region. When external light hits the p-type region, an electrical signal corresponding to the amount of received light is output. Therefore, the light receiving unit 121 outputs the intensity of external light as an electrical signal. Note that the structure of the photodiode is not limited to the above, and other structures may be adopted.

  In addition, the sensor chip 120 has a control circuit unit that processes an electrical signal of the light receiving unit 121. The control circuit unit acquires an electrical signal from the light receiving unit 121, and acquires a sensor signal by performing predetermined signal processing on the electrical signal. The control circuit unit outputs this sensor signal to an external ECU. Thus, the external ECU performs air conditioner control and the like based on the sensor signal.

  Further, the control circuit unit has a function of inputting a light emission command from an external ECU and causing the light emitting diode 130 to emit light according to the light emission command. The control circuit unit may be formed on a semiconductor chip different from the sensor chip 120. Another semiconductor chip may be stacked with the sensor chip 120, or may be disposed next to the sensor chip 120. Further, the light emission command of the light emitting diode 130 may be directly input to the light emitting diode 130 via a terminal, wiring, or the like by the external ECU without using the sensor chip 120.

  The light emitting diode 130 is a light emitting element that emits light when driven by the control circuit unit of the sensor chip 120. That is, the light emitting diode 130 emits light according to a light emission command from an external ECU. The light emitting diode 130 serves as a security indicator.

  The light emitting diode 130 is disposed on the pedestal 111 of the holder 110. In the present embodiment, the light emitting diode 130 is separated from the sensor chip 120 and is disposed on the rear side of the vehicle with respect to the sensor chip 120.

  The light emitting diode 130 is configured to irradiate light having a wide wavelength such as visible light. Of course, the light emitting diode 130 may be configured to emit a single color. The light emitting diode 130 is electrically connected to a pad (not shown) provided on the sensor chip 120 by a bonding wire (not shown), for example. The pad is connected to the control circuit unit.

  The filter 140 is a hemispherical shell cover. The filter 140 is assembled to the holder 110 by a fitting claw structure so as to cover the pedestal 111 of the holder 110. Such a filter 140 has a lens portion 141. In the present embodiment, the traveling direction side of the vehicle in the filter 140 is configured as the lens unit 141. The light sensor 100 is mounted on the vehicle so that the lens unit 141 is positioned in front of the vehicle, that is, on the vehicle traveling side.

  The lens unit 141 is configured to collect external light on the light receiving unit 121 of the sensor chip 120. Specifically, a portion corresponding to the upper side of the sensor chip 120 in the lens portion 141 is formed thin, and a portion on the holder 110 side in the lens portion 141 is formed thick. Thus, since the lens part 141 is comprised in the lens shape by the thick part and the thin part, it becomes possible to condense the external light from the vehicle front and vehicle upper direction to the light-receiving part 121 of the sensor chip 120. ing.

  In addition, the filter 140 is textured on both the inner surface 142 on the holder 110 side and the outer surface 143 opposite to the inner surface 142. Then, on the inner surface 142 of the filter 140 that has been subjected to the texture processing, the roughness of the texture processing in the inner region 144 of the inner surface 142 is rougher than the roughness of the texture processing in the peripheral region 145 surrounding the inner region 144. It has become. Similarly, in the outer surface 143 of the filter 140 that has been subjected to the graining process, the graining roughness in the inner region 146 of the outer surface 143 is greater than the graining roughness in the peripheral region 147 surrounding the inner region 146. It is rough.

  As described above, since the roughness of the embossing process is different between the inside and the outside of each surface 142, 143 of the filter 140, the light of the light emitting diode 130 is less likely to be scattered in the inner regions 144, 146 than in the peripheral regions 145, 147. .

  Further, as shown in FIG. 2, the inner region 146 of the outer surface 143 of the filter 140 is provided so as to be positioned at the center (on the central axis) when the filter 140 is viewed on the pedestal 111 side of the holder 110. ing. Although not shown, the inner region 144 of the inner surface 142 of the filter 140 is similarly provided so as to be positioned at the center when the filter 140 is viewed on the pedestal 111 side of the holder 110. The above is the overall configuration of the light sensor 100 according to the present embodiment.

  Next, the effect of the difference in the roughness of the texture applied to the filter 140 will be described. First, as shown in FIG. 3A, the peripheral areas 145 and 147 of the respective surfaces 142 and 143 of the filter 140 are finer-textured than the inner areas 144 and 146, so that external light is scattered. It becomes easy. That is, the light intensity of the light emitting diode 130 is reduced. On the other hand, as shown in FIG. 3B, the inner regions 144 and 146 of the respective surfaces 142 and 143 of the filter 140 are rougher than the peripheral regions 145 and 147, so Becomes difficult to scatter.

  Therefore, as shown in FIG. 4, the light intensity of the light emitting diodes emitted from the outer surface 143 of the filter 140 is relatively higher in the inner region 146 than in the peripheral region 147. That is, the contrast of light between the inner region 146 and the peripheral region 147 on the outer surface 143 of the filter 140 is increased. Since the texture of the peripheral region 147 is much finer than that of the inner region 146, the directional light of the light emitting diode 130 is scattered by the peripheral region 147 and becomes very weak light.

  In FIG. 4, a region where the light intensity of the light emitting diode 130 is high is indicated by fine hatching, and a region where the light intensity of the light emitting diode 130 is low is indicated by rough hatching.

  As described above, the light intensity of the inner region 146 of the outer surface 143 of the filter 140 is increased, so that the light of the light emitting diode 130 can be seen uniformly regardless of the viewing direction with respect to the filter 140.

  Further, since the inner regions 144 and 146 of the respective surfaces 142 and 143 of the filter 140 are located at the center when the filter 140 is viewed from the pedestal portion 111, the visibility from the entire circumference of the light sensor 100, that is, the light emitting diode 130 is obtained. The appearance of the light can be improved.

(Second Embodiment)
In the present embodiment, parts different from the first embodiment will be described. As shown in FIG. 5, the sensor chip 120 has a gel resin 122. The gel-like resin 122 is provided so as to cover the entire light receiving unit 121. The gel-like resin 122 plays a role of scattering external light incident on the light receiving unit 121 through the inner regions 144 and 146 and the peripheral regions 145 and 147 of the respective surfaces 142 and 143 of the filter 140 and guiding the light to the light receiving unit 121.

  For example, silicone gel is employed as the gel resin 122. In addition, a white or translucent gel-like resin 122 may be used. In other words, any gel material that can scatter external light incident on the gel resin 122 may be used.

  According to the above configuration, the non-uniform intensity of external light that has passed through the inner regions 144 and 146 and the peripheral regions 145 and 147 of the respective surfaces 142 and 143 of the filter 140 is uniformly scattered by the gel-like resin 122. The intensity of the external light incident on the part 121 can be made uniform.

(Other embodiments)
The configuration of the light sensor 100 shown in each of the above embodiments is an example, and is not limited to the configuration shown above, and may be another configuration that can realize the present invention. For example, the light sensor 100 is not limited to in-vehicle use.

  In each of the above embodiments, the roughness of the embossing process changes in two stages, that is, the inner areas 144 and 146 and the peripheral areas 145 and 147. For example, the roughness changes stepwise or continuously in three stages or more. You may do it. That is, by making the graining roughness two steps as in the above embodiments, the light of the light emitting diode 130 can be seen uniformly regardless of the viewing direction with respect to the filter 140. Therefore, the graining roughness is 3 The same effect can be obtained by changing more than a step or continuously.

  In each of the above-described embodiments, the graining roughness is changed on both the inner surface 142 and the outer surface 143 of the filter 140, but this is an example. For example, the inner surface 142 of the filter 140 may not be textured, and the roughness of the texture processing may be changed between the inner region 146 and the peripheral region 147 of the outer surface 143. On the contrary, the outer surface 143 of the filter 140 may not be subjected to the texture processing, and the roughness of the texture processing may be changed between the inner region 144 and the peripheral region 145 of the inner surface 142.

  In each of the above embodiments, the inner regions 144 and 146 are provided so as to be positioned at the center when the filter 140 is viewed on the pedestal 111 side of the holder 110, but this is an example of the arrangement of the inner regions 144 and 146. It is not necessary to be at the center position.

110 Holder 120 Sensor chip 121 Light receiving unit 130 Light emitting diode 140 Filter 141 Lens unit 142 Inner surface 143 Outer surface 144, 146 Inner region 145, 147 Peripheral region

Claims (4)

A holder (110) having a pedestal (111);
A sensor chip that is disposed on the pedestal portion (111), has a light receiving portion (121) that detects the intensity of light, and acquires a sensor signal based on the intensity of external light received by the light receiving portion (121). (120),
A light emitting diode (130) disposed on the pedestal portion (111) and emitting light according to a light emission command;
A filter (140 having a hemispherical shell shape, having a lens part (141) for condensing external light on the light receiving part (121), and assembled to the holder (110) so as to cover the pedestal part (111). )When,
With
The filter (140) is textured on one or both of the inner surface (142) on the holder (110) side and the outer surface (143) opposite to the inner surface (142). And the roughness of the embossing in the inner region (144, 146) of the surface (142, 143) subjected to the embossing of the inner surface (142) and the outer surface (143). A light sensor characterized by being rougher than the roughness of the embossing in a peripheral region (145, 147) surrounding the region (144, 146).   The sensor chip (120) is provided so as to cover the whole of the light receiving part (121), and the sensor chip (120) passes through the inner region (144, 146) and the peripheral region (145, 147) of the filter (140). The light sensor according to claim 1, further comprising a gel resin (122) that scatters the external light incident on the light receiving unit (121) and guides the external light to the light receiving unit (121).   The inner region (144, 146) is provided so as to be positioned at the center when the filter (140) is viewed on the pedestal (111) side of the holder (110). Item 3. The light sensor according to Item 1 or 2.   The light sensor according to any one of claims 1 to 3, wherein the lens unit (141) is mounted on the vehicle so as to be positioned in front of the vehicle.

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