JP7052216B2 - Light sensor - Google Patents

Description

The present invention relates to a light sensor.

Conventionally, a vehicle lamp automatic on / off device has been proposed, for example, in Patent Document 1. In this vehicle lamp automatic on / off device, flicker rays emitted by artificial lights such as tunnel lighting lights and street lights are detected as the output potential of the light receiving sensor, and the on / off of the vehicle lamp is controlled based on the output potential. To.

Japanese Unexamined Patent Publication No. 9-301052

By the way, as a light sensor, a configuration including an upper light sensor that detects light from above the vehicle and a front light sensor that detects light from the front of the vehicle is known. In this configuration, the light sensor detects light in two directions by each sensor, and if the upper light and the front light are lower (darker) than a certain threshold value, it determines that it is a tunnel and turns on the light, and only the front light is the threshold value. If it is higher (brighter) than that, it is judged that the bridge is broken and the light is kept off.

However, there is a possibility that the brightness in front will be reversed between a bright tunnel with high-intensity lighting and a long bridge. For this reason, there is a problem that the lighting of the vehicle light is delayed when entering a bright tunnel, or the light is turned on by a long bridge.

In view of the above points, it is an object of the present invention to provide a light sensor capable of distinguishing between a bright tunnel and a long bridge.

In order to achieve the above object, in the invention according to claim 1, the light sensor is a first light receiving element (130) that outputs the front light intensity of the front light emitted from the front of the vehicle (200) as a first light receiving signal. ), And a second light receiving element (140) that outputs the illumination light intensity of the illumination light emitted from above the front of the vehicle as a second light receiving signal.

Further, the light sensor inputs the first light receiving signal and the second light receiving signal, and performs a front light determination process for determining whether or not the front light intensity is smaller than the first threshold for determining the brightness of the tunnel. When the condition of the forward light determination process is not satisfied, the value is larger than the first threshold value and the forward light intensity is smaller than the second threshold value for determining the length of the bridge, and the tunnel and the bridge are distinguished. The vehicle performs the illumination light determination process for determining whether or not the illumination light intensity is higher than the third threshold value, and when the condition of the front light determination process is satisfied or the condition of the illumination light determination process is satisfied, the vehicle is used. It is provided with a determination unit (160) that determines that the front of the vehicle is a tunnel and determines that the front of the vehicle is a bridge when the condition of the illumination light determination process is not satisfied.

According to this, an intermediate region from the first threshold value to the second threshold value, which may be either a bright tunnel or a long bridge, is provided with respect to the forward light intensity of the forward light, and the third threshold value is provided in this intermediate region. Is set. Therefore, it is possible to determine that a bright tunnel and a long bridge are formed by comparing the illumination light intensity of the illumination light with the third threshold value. Therefore, it is possible to make a definite distinction between a bright tunnel and a long bridge.

The reference numerals in parentheses of each means described in this column and the scope of claims indicate the correspondence with the specific means described in the embodiment described later.

It is a schematic diagram of the light sensor which concerns on 1st Embodiment of this invention. It is sectional drawing of a light sensor. It is a figure which showed the relationship between the illuminance of light of each direction and a situation, and the position of each threshold value. It is a flowchart which showed the content which determines the tunnel entry of a vehicle in the daytime. It is sectional drawing of the light sensor which concerns on 3rd Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each of the following embodiments, the parts that are the same or equal to each other are designated by the same reference numerals in the drawings.

(First Embodiment)
Hereinafter, the first embodiment of the present invention will be described with reference to the drawings. The light sensor according to the present embodiment is applied to an auto light system that automatically turns on and off the headlights and tail lights of a vehicle when entering a bridge or a tunnel in the daytime, for example.

As shown in FIG. 1, the light sensor 100 is fixed to the passenger compartment side of the windshield 210 of the vehicle 200. Further, as shown in FIG. 2, the light sensor 100 includes a case 110, a circuit board 120, a first light receiving element 130, a second light receiving element 140, a third light receiving element 150, and a determination unit 160.

The case 110 is a housing for accommodating the light receiving elements 130 to 150, the determination unit 160, the circuit board 120, and the like. The case 110 is made of a metal material, a resin material, or the like. Further, the case 110 has a light guide unit 111 for introducing light, and the light guide unit 111 is fixed to the windshield 210 so as to be located on the windshield 210 side.

Each light receiving element 130 to 150, a determination unit 160, and an electronic component (not shown) are mounted on the circuit board 120. The circuit board 120 is fixed in the case 110.

Each of the light receiving elements 130 to 150 is a detection unit that detects light incident on the vehicle interior from the outside of the vehicle 200 via the windshield 210. Further, each of the light receiving elements 130 to 150 is configured as, for example, a photodiode, and outputs the intensity of the light received through the windshield 210 as a light receiving signal.

Further, each of the light receiving elements 130 to 150 is set to have a directivity of light so that the intensities of light received from a specific direction are different from each other. For example, in FIG. 2, the first light receiving element 130 has a light directivity set so that the intensity of the front light emitted from the front of the vehicle 200 is the highest. The first light receiving element 130 outputs the front light intensity of the front light as the first light receiving signal. The directivity of light is set by means such as a shading plate.

Similarly, the second light receiving element 140 outputs the illumination light intensity of the illumination light emitted from above the front of the vehicle 200 as the second light receiving signal. In the present embodiment, the second light receiving element 140 detects the illumination light emitted at an angle between the front and the upper side of the vehicle 200. The third light receiving element 150 outputs the upward light intensity of the upward light emitted from above the vehicle 200 as a third light receiving signal.

For example, the forward light is light incident on the light sensor 100 from each direction of 0 ° with respect to the road surface 300, the illumination light is 45 ° with respect to the road surface 300, and the upward light is 90 ° with respect to the road surface 300. These angles are examples, and the angles of the front light, the illumination light, and the upward light are appropriately set. Further, although FIG. 2 shows the light receiving elements 130 to 150 individually prepared, a plurality of photodiodes may be formed on one IC chip by a semiconductor process.

The determination unit 160 includes a CPU, ROM, RAM, etc. (not shown), and is a control circuit unit that performs signal processing according to a program stored in the ROM or the like. The determination unit 160 is configured as, for example, an IC chip and is mounted on the circuit board 120. Further, the determination unit 160 has a function of inputting each light receiving signal from each light receiving element 130 to 150 at any time or at a predetermined timing, determining whether the light of the vehicle 200 is turned on or off based on each light receiving signal, and outputting the result. have.

Further, the determination unit 160 has a threshold value for controlling the turning on and off of the light of the vehicle 200 by distinguishing between the tunnel and the bridge during the daytime. The determination unit 160 has, as one of the threshold values, a sudden change threshold value for determining whether or not the brightness above the vehicle 200 has suddenly changed. The sudden change threshold is set with respect to the upward light intensity of the upward light.

As shown in FIG. 3, the illuminance of the upward light changes from high illuminance to low illuminance regardless of whether it enters the bridge or the tunnel. “High”, “intermediate”, and “low” in FIG. 3 mean the level of illuminance.

The illuminance of the foreground light is high for short bridges, medium for long tunnels, medium for bright tunnels, and low for dark tunnels. The illuminance of the illumination light is medium for short bridges, low for long tunnels, medium for bright tunnels, and low for dark tunnels.

In response to such a difference in illuminance, the determination unit 160 has first to third threshold values as threshold values for turning on the light of the vehicle 200 at the bridge and turning it on at the tunnel during the daytime.

The first threshold value and the second threshold value are set with respect to the forward light intensity of the forward light. The first threshold value is a threshold value for determining the brightness of the tunnel, and is set to a value that distinguishes between a bright tunnel and a dark tunnel. Further, the second threshold value is a threshold value for determining the length of the bridge, and is set to a value that distinguishes between a long bridge and a short bridge. The second threshold value is a value larger than the first threshold value.

On the other hand, the third threshold value is set with respect to the illumination light intensity of the illumination light. The third threshold is a threshold for distinguishing between a long bridge and a bright tunnel. In the intermediate region, the difference in the illuminance of the front light between the long bridge and the bright tunnel is unlikely to occur, so that a third threshold value is set for the illuminance of the illumination light that clearly causes a difference. The above is the overall configuration of the light sensor 100 according to the present embodiment.

Next, the operation of the light sensor 100 during the daytime will be described with reference to the flowchart of FIG. The flowchart shown in FIG. 4 is executed when the mode for automatically turning on the light when the vehicle 200 enters the tunnel during the daytime is selected.

First, in step S170, an upward light determination process is performed as a sudden change determination. Specifically, it is determined whether or not the difference between the 60-second average value of the upward light intensity and the current upward light intensity is equal to or greater than the sudden change threshold value. That is, it is determined whether or not the upper part of the vehicle 200 suddenly becomes dark. For the 60-second average value of the upward light intensity, data calculated at any time by the determination unit 160 is used.

The difference between the 60-second average value of the upward light intensity and the current upward light intensity may be obtained as an absolute value and compared with the sudden change threshold value. Further, the determination method for sudden change determination is not limited to the above, and sudden change determination may be performed according to other determination criteria.

If it is determined in step S170 that the value of the upward light intensity has not suddenly changed, step S170 is executed again, and step S170 is repeated until the value of the upward light intensity suddenly changes. On the other hand, if it is determined that the value of the upward light intensity has changed suddenly, the process proceeds to step S171.

In step S171, as the first tunnel determination, a forward light determination process for determining whether or not the forward light intensity is smaller than the first threshold value for determining the brightness of the tunnel is performed. That is, it is determined whether or not the front of the vehicle 200 is dark.

If the condition of step S171 is satisfied, that is, if the front of the vehicle 200 is dark, it is determined that the front of the vehicle 200 is a tunnel, and the process proceeds to step S172. In this case, the vehicle 200 is in a state of entering the tunnel, and the ON of the light is confirmed. Therefore, in step S172, a lighting signal for turning on the light of the vehicle 200 is output to the auto light system. In this way, the light of the vehicle 200 is turned on, and the flow of FIG. 4 ends.

When the vehicle 200 exits the tunnel, another process for turning off the light is executed by the determination unit 160. Further, after the vehicle 200 exits the tunnel, the flow of FIG. 4 is executed again.

On the other hand, if the condition of step S171 is not satisfied, that is, if the front of the vehicle 200 is not dark, the process proceeds to step S173. In step S173, as the second tunnel determination, an illumination light determination process for distinguishing between the tunnel and the bridge is performed. Specifically, whether or not the forward light intensity is smaller than the second threshold value for determining the length of the bridge and the illumination light intensity is larger than the third threshold value for distinguishing between the tunnel and the bridge girder. It is judged.

In step S173, first, as shown in the table of FIG. 3, in the intermediate region of the forward light from the first threshold to the second threshold, there is a possibility of both a bright tunnel and a long bridge, and the light is turned on or turned on. It is difficult to confirm OFF. Therefore, first, it is determined that the brightness of the front light corresponds to the intermediate region. This is determined by whether or not the forward light intensity is smaller than the second threshold value.

Then, when the front light intensity is smaller than the second threshold value, that is, when the brightness of the front light corresponds to the intermediate region, whether or not the illumination light is larger than the third threshold value set in the intermediate region. Is determined. In the intermediate region, the illuminance of the illumination light in the long bridge is low, but the illuminance of the illumination light in the bright tunnel is about the middle. The difference in the illuminance of the illumination light is determined by the third threshold value.

If the condition of step S173 is satisfied, it is determined that the front of the vehicle 200 is a tunnel, and the process proceeds to step S172. That is, when the forward light intensity is smaller than the second threshold value and the illumination light is larger than the third threshold value, the ON of the light is confirmed.

On the other hand, if the condition of step S173 is not satisfied, it is determined that the front of the vehicle 200 is bridged, the lighting process of the light of the vehicle 200 is not performed, and the process returns to step S170 again. For example, when the forward light intensity is larger than the second threshold value, or when the illumination light is smaller than the third threshold value, the OFF of the light is confirmed. Then, unless the vehicle 200 enters the tunnel, the flow of FIG. 4 is repeated.

As described above, in the present embodiment, the lighting is installed in the tunnel, and the lighting is not installed in the bridge, so that the lighting can be detected. Also, a third threshold is set for intermediate regions where both bright tunnels and long bridges are possible. Therefore, it is possible to determine whether it is a bright tunnel or a long bridge by comparing the third threshold value with the illumination light intensity. Therefore, it is possible to make a definite distinction between a bright tunnel and a long bridge.

(Second Embodiment)
In this embodiment, a part different from the first embodiment will be described. In the present embodiment, the third threshold value is set for an intensity index which is a value obtained by dividing the illumination light intensity by the front light intensity.

The intensity index is a relative numerical value between the illumination light intensity and the front light intensity, and is a value closer to the actual situation. The determination unit 160 calculates and acquires the strength index at any time.

Then, in the illumination light determination process of step S172 shown in FIG. 4, determination using the intensity index is performed. That is, when it is determined in step S171 that the condition of the front light determination process is not satisfied, whether or not the front light intensity is smaller than the second threshold value and the intensity index is larger than the third threshold value in step S172. It is judged.

As described above, the strength index may be set. In a long bridge, the illuminance is relatively low with respect to the front light intensity, and in a bright tunnel, the illuminance is high with respect to the front light intensity. Can be high.

(Third Embodiment)
In this embodiment, the parts different from the first and second embodiments will be described. In the present embodiment, as shown in FIG. 5, the first light receiving element 130 for detecting the front light and the second light receiving element 140 for detecting the illumination light emitted from above the front of the vehicle 200 are two. It is configured to include light receiving elements 130 and 140. The second light receiving element 140 may detect the illumination light, and the directivity of the light may be set above the vehicle 200.

In this configuration, there is no upward light determination process in step S170 shown in FIG. Therefore, when the flow of FIG. 4 starts, step S171 is executed first. If the condition is not satisfied in step S173, the flow returns to step S171. As described above, it may be determined that a bright tunnel and a long bridge are formed by the two light receiving elements 130 and 140.

As a modification, the strength index may be set as in the second embodiment, and the determination in step S173 may be performed using the strength index.

(Other embodiments)
The configuration of the light sensor 100 shown in each of the above embodiments is an example, and the configuration is not limited to the configuration shown above, and other configurations that can realize the present invention can be used. For example, the light sensor 100 may be fixed to another place instead of the windshield 210.

100 Light sensor 110 Case 120 Circuit board 130-150 Light receiving element 160 Judgment unit 200 Vehicle

Claims (3)

A first light receiving element (130) that outputs the front light intensity of the front light emitted from the front of the vehicle (200) as a first light receiving signal, and
A second light receiving element (140) that outputs the illumination light intensity of the illumination light emitted from above the front of the vehicle as a second light receiving signal.
The front light determination process for inputting the first light receiving signal and the second light receiving signal to determine whether or not the front light intensity is smaller than the first threshold for determining the brightness of the tunnel, and the front light. When the condition of the determination process is not satisfied, the value is larger than the first threshold value, the front light intensity is smaller than the second threshold value for determining the length of the bridge, and the tunnel and the bridge are formed. The illumination light determination process for determining whether or not the illumination light intensity is larger than the third threshold for distinguishing is performed, and the condition of the front light determination process or the condition of the illumination light determination process is satisfied. In this case, the determination unit (160) determines that the front of the vehicle is the tunnel, and if the condition of the illumination light determination process is not satisfied, the front of the vehicle is the bridge.
Light sensor equipped with. A third light receiving element (150) that outputs the upward light intensity of the upward light emitted from above the vehicle as a third light receiving signal is provided.
The second light receiving element detects the intensity of the light emitted as the illumination light at an angle between the front and the upper side of the vehicle as the illumination light intensity, and outputs the second light receiving signal.
The determination unit inputs the third light receiving signal, performs an upward light determination process for determining whether or not the value of the upward light intensity has suddenly changed before the forward light determination process, and performs an upward light determination process in the upward light determination process. The light sensor according to claim 1, wherein when it is determined that the value of the upward light intensity has suddenly changed, the forward light determination process is performed. When the value obtained by dividing the illumination light intensity by the front light intensity is defined as the intensity index,
When the determination unit acquires the intensity index and does not satisfy the conditions for the front light determination process, the front light intensity is smaller than the second threshold value in the illumination light determination process, and the third threshold value is used. Instead of determining whether or not the illumination light intensity is higher than, it is determined whether or not the front light intensity is smaller than the second threshold value and the intensity index is larger than the third threshold value. The light sensor according to claim 1 or 2.

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