JP2015009762A - Photosensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photosensor capable of preventing erroneous lighting when passing below an architecture such as a bridge girder, and preventing lighting delay after entry into a tunnel.SOLUTION: A determination circuit part 19 has an upper visible light determination threshold value, an upper infrared determination threshold value, and a front infrared determination threshold value for determining whether or not to light headlights of a vehicle 53, and compares a signal inputted from each of detection elements 15-17 and the threshold value corresponding to the signal. The determination circuit part 19 outputs a lighting signal for lighting the headlights of the vehicle 53 when an upper visible light signal exceeds the upper visible light determination threshold value or an upper infrared signal exceeds the upper infrared determination threshold value, and a front infrared signal exceeds the front infrared determination threshold value.

Description

  The present invention relates to an optical sensor that receives light from above or in front of a vehicle.

  Conventionally, for example, Patent Document 1 proposes a light receiving device that operates an automatic light turn-on / off device when a vehicle enters a tunnel. Specifically, a first light receiving sensor that is sensitive to both visible light and infrared light above the vehicle, a second light receiving sensor that is sensitive only to infrared light above the vehicle, a first light receiving sensor, A configuration including a gate circuit that processes signals from two light receiving sensors has been proposed.

  In such a configuration, when the vehicle travels outdoors during the day, the first light receiving sensor and the second light receiving sensor receive natural light including both visible light and infrared light. As a result, the gate circuit does not operate the automatic light turn-off device that turns on the vehicle headlight, so the vehicle headlight is turned off.

  On the other hand, when the vehicle enters the tunnel, the first light receiving sensor receives visible light from a lamp in the tunnel. In addition, since the light from the lamp installed in the tunnel does not include infrared light, the second light receiving sensor does not receive infrared light. As a result, the gate circuit operates the automatic light turning-on / off device, so that the headlight of the vehicle is turned on.

Japanese Patent Laid-Open No. 11-105618

  However, in the above conventional technique, when the vehicle passes under a building such as a bridge instead of a tunnel, the first light receiving sensor and the second light receiving sensor include both visible light and infrared light from above the vehicle. Stops receiving natural light. That is, since the second light receiving sensor does not receive infrared light, the gate circuit operates the automatic light turn-on / off device. For this reason, there exists a problem that the headlight of a vehicle will light erroneously.

  On the other hand, US Pat. No. 6,376,824 proposes an optical sensor including a first light receiving unit that detects visible light ahead of the vehicle and a second light receiving unit that detects visible light above the vehicle. Each light receiving unit turns on the headlight when the intensity of the detected visible light falls below a threshold value. When a vehicle in which such a light sensor is installed passes under a bridge, the first light receiving unit has a visible light intensity lower than a threshold before the second light receiving unit. Will not light up.

  However, in the daytime, in the vicinity of the entrance of the tunnel, the lighting in the tunnel is set brighter in order to accustom the user's eyes. For this reason, even if the vehicle enters the tunnel, the intensity of visible light detected by each light receiving unit does not reach the threshold value. Therefore, after the vehicle enters the tunnel and travels for a while, the headlight is turned on after the inside of the tunnel becomes dark, resulting in a delay in turning on the headlight.

  From the above, it is desired to solve both the erroneous lighting when passing under a building such as a bridge and the lighting delay after entering the tunnel.

  In view of the above points, the present invention has an object to provide an optical sensor capable of preventing erroneous lighting when passing under a building such as a bridge and preventing lighting delay after entering a tunnel. To do.

  In order to achieve the above object, according to the first aspect of the present invention, the optical sensor has a reduced spectral sensitivity of visible light out of light irradiated from above the vehicle (53) and the intensity of the received light. Is provided as a first intensity signal. The optical sensor has a lower spectral sensitivity of visible light out of light emitted from the front of the vehicle (53), and outputs the intensity of the received light as a second intensity signal (17). ).

  Further, the optical sensor has a first threshold value and a second threshold value for determining whether or not to turn on the headlight of the vehicle (53), and inputs a first intensity signal from the first light receiving element (16). The first intensity signal is compared with the first threshold, the second intensity signal is input from the second light receiving element (17), the second intensity signal is compared with the second threshold, and the first intensity signal is A determination circuit unit (19) is provided that outputs a lighting signal for lighting the headlight of the vehicle (53) when the threshold value is exceeded and the second intensity signal exceeds the second threshold value. To do.

  According to this, since the light sensing direction is different between the first light receiving element (16) and the second light receiving element (17), when the vehicle (53) passes under a building such as a bridge, the first light receiving element is received. The timing at which the light intensity exceeds the threshold is different between the element (16) and the second light receiving element (17). Further, since the second light receiving element (17) receives the natural light before the first light receiving element (16), the intensity of the detection light is increased in both the first light receiving element (16) and the second light receiving element (17). The threshold is never exceeded. For this reason, the determination circuit unit (19) does not erroneously turn on the headlight of the vehicle (53).

  On the other hand, when the vehicle (53) enters the tunnel (56), natural light is not irradiated from the front of the vehicle (53), and thus the first light receiving element (immediately after the vehicle (53) enters the tunnel (56). In both 16) and the second light receiving element (17), the intensity of the detection light exceeds the threshold value. For this reason, the lighting delay of the headlight of the vehicle (53) by the determination circuit part (19) does not occur.

  Therefore, it is possible to prevent erroneous lighting when the vehicle (53) passes under a building such as a bridge, and to prevent a lighting delay after entering the tunnel (56).

  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 a photosensor in 1st Embodiment of this invention. It is the figure which showed the spectral sensitivity characteristic of an upper visible light detection element. It is the figure which showed the spectral sensitivity characteristic of an upper infrared light detection element and a front infrared light detection element. It is the figure which showed the circuit structure of the determination circuit part. It is a figure for demonstrating operation | movement of the determination circuit part at the time of a vehicle passing under the bridge. It is the figure which showed the spectral-luminance characteristic of the low pressure sodium lamp installed in a tunnel. It is a figure for demonstrating operation | movement of the determination circuit part when a vehicle approachs a tunnel. It is the figure which showed the circuit structure of the determination circuit part which concerns on 2nd Embodiment of this invention. In 2nd Embodiment, it is a figure for demonstrating operation | movement of the determination circuit part when a vehicle passes under the bridge. In 2nd Embodiment, it is a figure for demonstrating operation | movement of the determination circuit part when a vehicle approachs a tunnel. It is the figure which showed the circuit structure of the determination circuit part which concerns on 3rd Embodiment of this invention. In 3rd Embodiment, it is a figure for demonstrating operation | movement of the determination circuit part when a vehicle passes under the bridge. In 3rd Embodiment, it is a figure for demonstrating operation | movement of the determination circuit part when a vehicle approachs a tunnel. It is the perspective view which showed the partial cross section of the semiconductor chip which concerns on 4th Embodiment of this invention. It is a top view of the slit board used in 4th Embodiment. In 4th Embodiment, it is sectional drawing of the structure where the semiconductor chip and the slit board were accommodated in the sensor housing.

  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 optical sensor according to the present embodiment is applied to an autolight system that automatically turns off a headlight and a taillight of a vehicle when entering a tunnel or under a building such as a bridge during the day.

  As shown in FIG. 1, the optical sensor 10 includes a case 11, a plurality of lenses 12 to 14, an upper visible light detection element 15, an upper infrared light detection element 16, a front infrared light detection element 17, and a circuit board 18. It is configured with.

  The case 11 is a bottomed cylindrical casing that accommodates the plurality of lenses 12 to 14, the detection elements 15 to 17, and the circuit board 18. The case 11 is formed of a metal material or a resin material. The case 11 is fixed to the inner surface 51 of the windshield 50 so that a space 52 is formed between the case 11 and the inner surface 51 of the windshield 50 of the vehicle. Thereby, the plurality of lenses 12 to 14, the detection elements 15 to 17, and the circuit board 18 are arranged on the inner surface 51 side of the windshield 50.

  The plurality of lenses 12 to 14 are condensing means for collecting light incident from a predetermined direction among light incident on the windshield 50. The lens 12 has a directivity characteristic that guides light incident from above the vehicle, that is, from the ceiling side, to the upper visible light detection element 15. The lens 13 has a directivity characteristic that guides light incident from above the vehicle to the upper infrared light detection element 16. The lens 14 has a directivity characteristic that guides light incident from the front of the vehicle to the front infrared light detection element 17. Each lens 12-14 is being fixed to case 11 with the stay etc. which are not illustrated.

  The upper visible light detection element 15, the upper infrared light detection element 16, and the front infrared light detection element 17 are light receiving elements that detect light incident on the space 52 of the case 11 through the windshield 50. Specifically, each of the detection elements 15 to 17 includes a photodiode that detects the intensity of received light and a processing circuit (not shown) that amplifies the signal of the photodiode. Each of the detection elements 15 to 17 is mounted on the circuit board 18.

  The upper visible light detection element 15 is a light receiving element having a spectral sensitivity characteristic including visible light among light incident from above the vehicle via the lens 12. Specifically, the upper visible light detection element 15 has a spectral sensitivity characteristic capable of detecting both visible light and infrared light, as shown in FIG. The upper visible light detection element 15 outputs the intensity of the received light as an upper visible light signal. The intensity of light is, for example, a voltage value. The upper visible light detection element 15 may be configured to detect only visible light.

  On the other hand, as shown in FIG. 3, the upper infrared light detection element 16 and the front infrared light detection element 17 have a spectral sensitivity characteristic capable of detecting infrared light by reducing the spectral sensitivity of visible light. Have. The upper infrared light detection element 16 outputs the intensity of light received from above the vehicle through the lens 13 as an upper infrared light signal. The front infrared light detection element 17 outputs the intensity of light received from the front of the vehicle via the lens 14 as a front infrared light signal.

  For example, the upper infrared light detection element 16 and the front infrared light detection element 17 can be easily configured by providing a filter that blocks visible light in the light receiving element having the spectral sensitivity characteristic shown in FIG. Can do.

  The circuit board 18 is a drive circuit (not shown) for driving the detection elements 15 to 17 and a determination for determining whether or not to turn on the vehicle headlight based on the detection results of the detection elements 15 to 17. It has a circuit part. The circuit board 18 is fixed in the case 11.

  As illustrated in FIG. 4, the determination circuit unit 19 includes a plurality of comparators 20 to 22, AND circuits 23 and 24, and an OR circuit 25. The comparator 20 is a comparison unit that receives the upper visible light signal from the upper visible light detection element 15 and compares the amplitude of the upper visible light signal with the upper visible light determination threshold value. In the present embodiment, the comparator 20 outputs a Hi signal when the amplitude of the upper visible light signal is lower than the upper visible light determination threshold, and is Lo when the amplitude of the upper visible light signal exceeds the upper visible light determination threshold. Output a signal.

  The comparator 21 is a comparison unit that receives the upper infrared light signal from the upper infrared light detection element 16 and compares the amplitude of the upper infrared light signal with the upper infrared light determination threshold value. The comparator 21 outputs a Hi signal when the amplitude of the upper infrared light signal is lower than the upper infrared light determination threshold value, and outputs a Lo signal when the amplitude of the upper infrared light signal exceeds the upper infrared light determination threshold value. Is output.

  Further, the comparator 22 is a comparison unit that receives the front infrared light signal from the front infrared light detection element 17 and compares the amplitude of the front infrared light signal with the front infrared light determination threshold value. The comparator 20 outputs a Hi signal when the amplitude of the front infrared light signal is lower than the front infrared light determination threshold value, and outputs a Lo signal when the amplitude of the front infrared light signal exceeds the front infrared light determination threshold value. Is output.

  The upper visible light determination threshold, the upper infrared light determination threshold, and the front infrared light determination threshold are thresholds for determining whether to turn on the headlight of the vehicle. Each threshold value is preset in a memory, a latch, or the like (not shown) so as to have a predetermined value.

  The AND circuit 23 is connected to the comparator 20 and the comparator 1 so as to invert the output of the comparator 20 and to input the output of the comparator 21. Actually, the AND circuit 23 inputs the output of the comparator 20 via a NOT circuit (not shown). The AND circuit 23 outputs a Hi signal when the output of the comparator 20 is Lo and the output of the comparator 21 is Hi, and outputs a Lo signal otherwise.

  The OR circuit 25 is connected to the comparator 20 and the AND circuit 23 so as to receive the output of the comparator 20 and the output of the AND circuit 23. The OR circuit 25 outputs a Hi signal when either the output of the comparator 20 or the output of the AND circuit 23 is Hi, and Lo when the output of the comparator 20 or the output of the AND circuit 23 is Lo. The signal is output.

  The AND circuit 24 is connected to the OR circuit 25 and the comparator 22 so as to receive the output of the OR circuit 25 and the output of the comparator 22. The AND circuit 24 outputs a Hi signal when both the output of the OR circuit 25 and the output of the comparator 22 are Hi, and outputs a Lo signal otherwise. The Hi signal output from the AND circuit 24 is a lighting signal for lighting the headlight of the vehicle.

  Therefore, the determination circuit unit 19 determines whether the upper visible light signal is lower than the upper visible light determination threshold or the upper infrared light signal is lower than the upper infrared light determination threshold, and the front infrared light signal is determined to be the front infrared light determination. When the value falls below the threshold value, a Hi lighting signal for lighting the headlight of the vehicle 53 is output.

  The above is the overall configuration of the optical sensor 10 according to the present embodiment. The lighting signal output from the determination circuit unit 19 is input to an external device that operates the headlight of the vehicle. The external device turns on the headlight when the lighting signal is Hi, and turns off the headlight when the lighting signal is Lo.

  Next, the operation of the optical sensor 10 when the vehicle passes under a building such as a bridge during the day will be described. As shown in FIG. 5, the vehicle 53 is about to pass under the bridge 54. 5, the horizontal axis indicates the position of the vehicle 53, and the vertical axis indicates the outputs of the detection elements 15 to 17 and the output of the determination circuit unit 19.

  First, before the vehicle 53 enters the bridge 54, there is no building that blocks natural light above and in front of the vehicle 53. For this reason, the output of each detection element 15-17 is kept at the value which exceeds each threshold value, respectively.

  At the point L10, the vehicle 53 further approaches the bridge 54. The outputs of the upper visible light detection element 15 and the upper infrared light detection element 16 that detect natural light from above the vehicle 53 are above the respective threshold values. On the other hand, the output of the front infrared light detection element 17 that detects infrared light from the front of the vehicle 53, that is, the amplitude of the front infrared light signal starts to decrease.

  At this point L10, since the outputs of the comparators 20 to 22 are Lo, the output of the AND circuit 24 is also Lo. Therefore, the determination circuit unit 19 outputs a Lo lighting signal. For this reason, the headlight is not turned on.

  Since the vehicle 53 is located in front of the bridge 54 at the point L11, the outputs of the upper visible light detection element 15 and the upper infrared light detection element 16 that detect light from above the vehicle 53 exceed the respective threshold values. ing. That is, since the outputs of the comparator 20 and the comparator 21 are Lo, the output of the OR circuit 25 is Lo.

  On the other hand, since the bridge 54 is located in front of the vehicle 53, the output of the front infrared light detection element 17 that detects light from the front of the vehicle 53 is lower than the front infrared light determination threshold. For this reason, the output of the comparator 22 becomes Hi. In FIG. 5, the state where the output of the comparator is Hi is indicated by “ON”. However, since the Lo signal is input from the OR circuit 25 to the AND circuit 24, the lighting signal becomes the Lo signal. For this reason, the headlight is not turned on.

  At the point L12, the vehicle 53 starts to enter the bridge 54. Thereby, since the intensity | strength of the natural light from the upper direction of the vehicle 53 falls, each output of the upper visible light detection element 15 and the upper infrared light detection element 16 begins to fall. Further, the amplitude of the front infrared light detection element 17 also decreases. At this point L12, since the determination circuit unit 19 maintains the same state as that at the point L11, it continues to output the Lo lighting signal.

  Since the vehicle 53 enters the bridge 54 to some extent at the point L13, natural light including infrared light is irradiated from the exit side of the bridge 54 to the vehicle 53 side. For this reason, the output of the front infrared light detection element 17 which detects the infrared light from the front of the vehicle 53 rises and exceeds the front infrared light determination threshold. That is, the output of the comparator 22 becomes Lo. On the other hand, each output of the upper visible light detection element 15 and the upper infrared light detection element 16 does not fall below each threshold value. For this reason, the output of the OR circuit 25 is maintained in the Lo state. Therefore, the lighting signal output from the AND circuit 24 is Lo, and the headlight is not lit.

  At the point L14, the vehicle 53 approaches the position farthest from the entrance / exit among the bridges 54, so that the intensity of natural light irradiated under the bridge 54 is weakened. For this reason, the output of the upper visible light detection element 15 that detects visible light from above the vehicle 53 falls below the upper visible light determination threshold. Similarly, the output of the upper infrared light detection element 16 that detects infrared light from above the vehicle 53 falls below the upper infrared light determination threshold. Therefore, since the comparator 20 and the comparator 21 each output a Hi signal, the OR circuit 25 outputs a Hi signal.

  On the other hand, as the vehicle 53 approaches the exit of the bridge 54, the intensity of natural light including infrared light emitted from the front of the vehicle 53 increases. Therefore, the output of the front infrared light detection element 17 is the front infrared light. The judgment threshold is exceeded. For this reason, since the comparator 22 outputs a Lo signal, the lighting signal output from the AND circuit 24 becomes Lo. Therefore, the headlight is not turned on.

  Since the vehicle 53 approaches the exit of the bridge 54 at the point L15, the intensity of natural light irradiated under the bridge 54 is increased. For this reason, each output of the upper visible light detection element 15 and the upper infrared light detection element 16 exceeds each threshold value. Further, the output of the front infrared light detection element 17 also exceeds the front infrared light determination threshold. That is, the output of the OR circuit 25 becomes Hi, but the output of the comparator 22 becomes Lo. Therefore, the lighting signal output from the AND circuit 24 is Lo, and the headlight is not lit.

  At the point L16, the vehicle 53 is located at the exit of the bridge 54. At this point, each of the detection elements 15 to 17 detects natural light, so that the headlight is not turned on as is the case with the point L10.

  As described above, even if the vehicle 53 passes under the bridge 54, the headlight of the vehicle 53 is not turned on. This is because although the intensity of natural light including infrared light decreases under the bridge 54, the front infrared light detection element 17 detects natural light that has entered the bridge 54 from the exit side of the bridge 54. It is. That is, the upper infrared light detection element 16 and the front infrared light detection element 17 have different directions for detecting infrared light. In other words, when the vehicle 53 passes under the bridge 54, the upper infrared light detection element 16 and the front infrared light detection element 17 have different timings at which the intensity of the infrared light falls below the threshold value. That is, the front infrared light detection element 17 detects natural light including infrared light before the upper infrared light detection element 16. Accordingly, the outputs of both the upper infrared light detection element 16 and the front infrared light detection element 17 do not exceed the threshold at the same timing. For this reason, it is possible to prevent the determination circuit unit 19 from erroneously lighting the headlight of the vehicle 53.

  Next, the operation of the optical sensor 10 when the vehicle 53 enters the tunnel during the day will be described. First, as shown in FIG. 6, a lamp used as tunnel illumination has a spectral luminance characteristic with a wavelength in the range of 550 nm to 600 nm. In other words, the lamp emits light that does not contain infrared light. Such a lamp is for example a low-pressure sodium lamp.

  And as FIG. 7 shows, the vehicle 53 is going to approach into the tunnel 56 in which the lamp | ramp 55 which emits the artificial light which does not contain infrared light was installed.

  At the point L20, the vehicle 53 approaches the tunnel 56. The outputs of the upper visible light detection element 15 and the upper infrared light detection element 16 that detect natural light from above the vehicle 53 are above the respective threshold values. On the other hand, the output of the front infrared light detection element 17 that detects infrared light from the front of the vehicle 53 starts to decrease. At this point L20, as in the above-described point L10, the determination circuit unit 19 outputs a Lo lighting signal, so the headlight is not turned on.

  At the point L21, the vehicle 53 approaches to the vicinity of the entrance of the tunnel 56. In this case, similarly to the point L11 described above, the outputs of the upper visible light detection element 15 and the upper infrared light detection element 16 exceed the respective threshold values, and the output of the front infrared light detection element 17 is the front infrared light determination threshold value. Below. For this reason, since the outputs of the comparator 20 and the comparator 21 are Lo, the output of the OR circuit 25 is Lo, so the output of the OR circuit 25 is Lo. Further, the output of the comparator 22 becomes Hi. Therefore, the lighting signal becomes a Lo signal, and the headlight is not lit.

  At the point L22, the vehicle 53 starts entering the tunnel 56. Thereby, since the intensity | strength of the natural light from the upper direction of the vehicle 53 falls, each output of the upper visible light detection element 15 and the upper infrared light detection element 16 begins to fall. Further, near the entrance of the tunnel 56, the vehicle 53 side is not irradiated with light including infrared light from the destination of the vehicle 53, so the output of the front infrared light detection element 17 is also reduced. At the point L22, the determination circuit unit 19 maintains the same state as the point L21, and therefore continues to output the Lo lighting signal.

  Here, as the vehicle 53 advances from the point L22 into the tunnel 56, the intensity of the visible light in the tunnel 56 decreases, so the output of the upper visible light detection element 15 also decreases. Further, since visible light is emitted from the lamp 55 installed in the tunnel 56, the output of the upper visible light detection element 15 increases every time the vehicle 53 passes under the lamp 55. Therefore, as shown in FIG. 7, the output of the upper visible light detection element 15 decreases in a wave shape.

  At the point L23, the output of the upper visible light detection element 15 exceeds the upper visible light determination threshold, but the output of the upper infrared light detection element 16 is lower than the upper infrared light determination threshold. For this reason, the output of the comparator 20 becomes Lo and the output of the comparator 21 becomes Hi, so that the output of the AND circuit 23 becomes Hi, and consequently the output of the OR circuit 25 becomes Hi. Further, the output of the front infrared light detection element 17 is kept below the front infrared light determination threshold. For this reason, the output of the comparator 22 maintains Hi. Therefore, the determination circuit unit 19 outputs a Hi lighting signal for lighting the headlight of the vehicle 53 from the AND circuit 24.

  At the point L24, the output of the upper visible light detection element 15 is lower than the upper visible light determination threshold. For this reason, the output of the comparator 20 becomes Hi. In this case, the output of the AND circuit 23 becomes Lo, but the output of the OR circuit 25 maintains Hi, so that the output of the AND circuit 24 maintains Hi. Therefore, the determination circuit unit 19 continues to output the Hi lighting signal.

  Note that natural light including infrared light is irradiated on the exit side of the tunnel 56. For this reason, the output of the front infrared light detection element 17 exceeds the front infrared light determination threshold value, and the output of the comparator 22 becomes Lo. As a result, the determination circuit unit 19 outputs the Lo lighting signal from the AND circuit 24, so that the headlight is turned off.

  As described above, when the vehicle 53 enters the tunnel 56, the headlight is turned on immediately. This is because when the vehicle 53 enters the tunnel 56, the light of the lamp 55 is irradiated from the front of the vehicle 53 without being irradiated with natural light including infrared light. That is, immediately after the vehicle 53 enters the tunnel 56, the outputs of the upper infrared light detection element 16 and the front infrared light detection element 17 are below the threshold values. For this reason, the determination circuit unit 19 can be prevented from causing a delay in lighting of the headlight of the vehicle 53.

  As described above, in the present embodiment, the determination circuit unit 19 can prevent erroneous lighting when the vehicle 53 passes under a building such as 54 bridged, and lighting after entering the tunnel 56. Delay can be prevented. In the present embodiment, visible light is detected by the upper visible light detection element 15. As a result, the determination can be made without being influenced by the weather, such as the difference between sunny and cloudy.

  As for the correspondence between the description of the present embodiment and the description of the claims, the upper visible light detection element 15 corresponds to the “third light receiving element” of the claims. The upper infrared light detection element 16 corresponds to a “first light receiving element” in the claims, and the front infrared light detection element 17 corresponds to a “second light receiving element” in the claims.

  The upper visible light determination threshold corresponds to the “third threshold” in the claims, and the upper infrared light determination threshold corresponds to the “first threshold” in the claims. Further, the front infrared light determination threshold corresponds to the “second threshold” in the claims.

  The upper visible light signal corresponds to the “third intensity signal” in the claims, and the upper infrared light signal corresponds to the “first intensity signal” in the claims. The front infrared light signal corresponds to a “second intensity signal” in the claims.

(Second Embodiment)
In the present embodiment, parts different from the first embodiment will be described. As shown in FIG. 8, the determination circuit unit 19 includes a threshold change circuit unit 26. The threshold value changing circuit unit 26 is a circuit unit that receives the output signal of the comparator 20 and changes the upper infrared light determination threshold value according to the output signal.

  Specifically, the threshold changing circuit unit 26 changes the upper infrared light determination threshold by increasing the upper infrared light determination threshold when the front infrared light signal falls below the front infrared light determination threshold. It has a function of advancing the timing when the upper infrared light signal falls below the upper infrared light determination threshold than before. In other words, when the intensity of infrared light from the front of the vehicle 53 decreases, the threshold value changing circuit unit 26 makes it easy to detect a decrease in the intensity of infrared light from above the vehicle 53.

  Next, the operation of the determination circuit unit 19 when the vehicle 53 passes under the bridge 54 during the day will be described with reference to FIG. At the point L30, the determination circuit unit 19 outputs a Lo lighting signal in the same manner as the point L10 described above.

  Subsequently, at the point L31, similarly to the point L11, the output of the comparator 22 changes from Lo to Hi. For this reason, the threshold value changing circuit unit 26 increases the upper infrared light determination threshold value. However, at the point L31, the outputs of the upper visible light detection element 15 and the upper infrared light detection element 16 exceed the respective threshold values.

  Thereafter, at the point L32, the outputs of the upper visible light detecting element 15 and the upper infrared light detecting element 16 begin to decrease, as in the point L12. Further, the output of the front infrared light detection element 17 exceeds the front infrared light determination threshold. That is, the output of the comparator 22 becomes Lo. For this reason, the threshold value changing circuit unit 26 returns the upper infrared light determination threshold value to the original value.

  Thereafter, at the point L33, the point L34, and the point L35, the determination circuit unit 19 performs the same operation as the point L14, the point L15, and the point L16 described above.

  Next, the operation of the determination circuit unit 19 when the vehicle 53 enters the tunnel 56 during the day will be described with reference to FIG. At the point L40, similarly to the point L20, the output of the front infrared light detection element 17 starts to decrease.

  Subsequently, at the point L41, similarly to the point L21, the output of the front infrared light detection element 17 is lower than the front infrared light determination threshold, so the output of the comparator 22 is Hi. Thereby, the threshold value changing circuit unit 26 increases the upper infrared light determination threshold value.

  Then, when the vehicle 53 enters the tunnel 56 from the point L42, the output of the upper infrared light detection element 16 is lower than the changed upper infrared light determination threshold at the point L43 similarly to the point L23. As described above, since the upper infrared light determination threshold is larger than the normal value, the timing at which the output of the upper infrared light detection element 16 falls below the upper infrared light determination threshold is advanced. Then, the determination circuit unit 19 outputs a Hi lighting signal for lighting the headlight of the vehicle 53.

  Thereafter, at the point L44, the determination circuit unit 19 operates in the same manner as the point L24 described above. At the exit side of the tunnel 56, the threshold value changing circuit unit 26 returns the upper infrared light determination threshold value to the original value at a timing when the output of the front infrared light detection element 17 exceeds the front infrared light determination threshold value. Further, since the output of the comparator 22 becomes Lo, the headlight is turned off.

  As described above, the outputs of both the upper infrared light detection element 16 and the front infrared light detection element 17 are the threshold values after the vehicle 53 enters the tunnel 56 rather than when the upper infrared light determination threshold value is a fixed value. The timing of exceeding will be earlier. Therefore, the headlight can be turned on immediately after the vehicle 53 enters the tunnel 56.

(Third embodiment)
In the present embodiment, parts different from the first embodiment will be described. As shown in FIG. 11, in the present embodiment, the determination circuit unit 19 includes a headlight luminance conversion circuit unit 27 and a switch 28.

  The headlight luminance conversion circuit unit 27 is connected to the upper visible light detection element 15 so as to input an upper visible light signal from the upper visible light detection element 15. The headlight luminance conversion circuit unit 27 is configured as a differential amplifier circuit by resistors 29 and 30 and an operational amplifier 31. As a result, the headlight luminance conversion circuit unit 27 reduces the upper visible light signal until the upper visible light signal exceeds the upper visible light determination threshold when the Hi lighting signal is output from the AND circuit 24. Accordingly, it has a function of increasing the brightness of the headlight of the vehicle 53.

  The switch 28 is configured to be turned on when the lighting signal is Hi. The switch 28 is, for example, a semiconductor switch. The switch 28 connects the headlight luminance conversion circuit unit 27 and an external headride driving device 57. The headlight driving device 57 is a device that drives the headlight of the vehicle 53.

  Next, in the above configuration, the operation of the determination circuit unit 19 when the vehicle 53 passes under the bridge 54 during the day will be described with reference to FIG. As described above, the headlight is not turned on when the vehicle 53 passes under the bridge 54. Therefore, the luminance of the headlight does not change as shown in FIG.

  In addition, at the point L50, the point L51, the point L52, the point L53, the point L54, the point L55, and the point L55, the determination circuit unit 19 is the above-described point L10, point L11, point L12, point L13, point L14, point L15, And the operation | movement similar to the point L15 is performed.

  Next, the operation of the determination circuit unit 19 when the vehicle 53 enters the tunnel 56 during the day will be described with reference to FIG. First, at the point L60, the point L61, and the point L62, the determination circuit unit 19 performs the same operation as the point L20, the point L21, and the point L22.

  Subsequently, at the point L63, similarly to the point L23, the output of the upper infrared light detection element 16 is lower than the upper infrared light determination threshold value, so the output of the comparator 21 is Hi. Therefore, the determination circuit unit 19 outputs a Hi lighting signal from the AND circuit 24. As a result, the switch 28 is turned ON.

  When the vehicle 53 further proceeds from the point L63, the headlight luminance conversion circuit unit 27 sends a luminance signal that increases as the amplitude of the upper visible light signal input from the upper visible light detection element 15 decreases from the operational amplifier 31 to the head. Output to the ride driving device 57. As a result, the head ride driving device 57 increases the luminance of the headlight of the vehicle 53 in accordance with the luminance signal.

  Thereafter, at the point L64, the determination circuit unit 19 performs the same operation as that at the point L24. Further, since the output of the upper visible light detection element 15 is lower than the upper visible light determination threshold at the point L64, the headlight luminance conversion circuit unit 27 outputs the maximum value as the luminance signal. As a result, the luminance of the headlight is a maximum value and a constant value.

  As described above, the headlight luminance conversion circuit unit 27 adjusts the luminance of the headlight in accordance with the illuminance of the lamp 55 installed near the entrance of the tunnel 56. For this reason, the user's uncomfortable feeling after entering the tunnel 56 can be reduced.

(Fourth embodiment)
In the present embodiment, parts different from the first to third embodiments will be described. As shown in FIG. 14, in the present embodiment, each of the detection elements 15 to 17 is formed on one semiconductor chip 32.

  The semiconductor chip 32 has a circular light receiving region 33. The light receiving region 33 is divided into a circular light receiving region 34, a ring-shaped light receiving region 35, and a ring-shaped light receiving region 36 from the center to the outside. Each of the light receiving regions 34 to 36 is electrically insulated.

  Specifically, a circular p-type region 38 is formed on the surface layer portion of the n-type silicon substrate 37, and a ring-shaped p-type region 39 and a p-type region 40 are formed on the outer periphery thereof. A cathode electrode 41 is formed on the back surface of the n-type silicon substrate 37, and anode electrodes 42, 43, 44 are provided in the p-type regions 38 to 40 on the front surface side of the n-type silicon substrate 37. Note that each of the light receiving regions 34 to 36 may be formed in a ring shape.

  For example, the circular light receiving region 34 is configured as the front infrared light detection element 17. Further, the ring-shaped light receiving region 35 is configured as the upper visible light detecting element 15, and the ring-shaped light receiving region 36 is configured as the upper infrared light detecting element 16. When light strikes each of the light receiving regions 34 to 36, an electrical signal corresponding to the amount of light received is output.

  Further, in order for each of the light receiving regions 34 to 36 to selectively receive light from above or in front of the vehicle 53, a slit plate 45 shown in FIG. . The slit plate 45 is made of a light shielding material. The slit plate 45 has a through hole 46 as a slit penetrating the slit plate 45. The through hole 46 has a circular shape, for example. The planar shape of the through hole 46 may be, for example, a polygonal shape, an L shape, an I shape, or the like.

  As shown in FIG. 16, the semiconductor chip 32 and the slit plate 45 are accommodated in the sensor housing 47. The light guided into the sensor housing 47 via the optical lens 48 is received by any one of the light receiving regions 34 to 36 according to the incident angle with respect to the through hole 46 of the slit plate 45.

  As described above, the direction of light received by each of the light receiving regions 34 to 36 can be selected by the slit plate 45. Further, the optical sensor 10 can be arranged not on the windshield 50 of the vehicle 53 but on, for example, a dashboard.

(Other embodiments)
The configuration of the optical sensor 10 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 threshold value changing circuit unit 26 shown in the second embodiment may be employed in the determination circuit unit 19 according to the third embodiment.

  Further, the upper visible light detection element 15 provided in each of the above embodiments may be unnecessary. In this case, the determination circuit unit 19 inputs the first intensity signal from the upper infrared light detection element 16 and compares the first intensity signal with the upper infrared light determination threshold value. The second intensity signal is input and the second intensity signal is compared with the front infrared light determination threshold. When the first intensity signal exceeds the first threshold value and the second intensity signal exceeds the front infrared light determination threshold value, the determination circuit unit 19 outputs a lighting signal for lighting the headlight of the vehicle 53. To do. Such a configuration may be adopted. In this case, as in the fourth embodiment, the upper infrared light detection element 16 and the front infrared light detection element 17 may be formed on one semiconductor chip 32.

  Further, in each of the embodiments described above, each of the comparators 20 to 22 outputs a Hi signal when the signal falls below the threshold, but this is an example of a determination method. Therefore, the determination circuit unit 19 may be configured to detect that the signal exceeds the threshold value. Of course, the circuit configuration of the determination circuit unit 19 shown in each of the above embodiments is merely an example, and may be configured by another circuit that can realize the function of the determination circuit unit 19.

15 Upper visible light detecting element (third light receiving element)
16 Upper infrared light detection element (first light receiving element)
17 Front infrared light detecting element (second light receiving element)
DESCRIPTION OF SYMBOLS 19 Determination circuit part 26 Threshold value change circuit part 27 Headlight brightness | luminance conversion circuit part 32 Semiconductor chip 53 Vehicle

Claims (6)

A first light receiving element (16) for reducing the spectral sensitivity of visible light out of light emitted from above the vehicle (53) and outputting the intensity of the received light as a first intensity signal;
A second light receiving element (17) for reducing the spectral sensitivity of visible light among the light irradiated from the front of the vehicle (53) and outputting the intensity of the received light as a second intensity signal;
The vehicle has a first threshold value and a second threshold value for determining whether to turn on the headlight of the vehicle (53), and receives the first intensity signal from the first light receiving element (16) and the first threshold value. The first intensity signal is compared with the first threshold, the second intensity signal is input from the second light receiving element (17), the second intensity signal is compared with the second threshold, and the first intensity is compared. A determination circuit unit (19) that outputs a lighting signal for lighting a headlight of the vehicle (53) when a signal exceeds the first threshold value and the second intensity signal exceeds the second threshold value. When,
An optical sensor comprising:   When the first intensity signal exceeds the first threshold, the timing at which the second intensity signal exceeds the second threshold is advanced by changing the second threshold than before changing the second threshold. The optical sensor according to claim 1, further comprising a threshold value changing circuit section.   The optical sensor according to claim 1 or 2, wherein the first light receiving element (16) and the second light receiving element (17) are formed on one semiconductor chip (32). A third light receiving element (15) having a spectral sensitivity characteristic including visible light out of light emitted from above the vehicle (53) and outputting the intensity of the received light as a third intensity signal,
The determination circuit unit (19) has a third threshold value for determining whether or not to turn on the headlight of the vehicle (53), and receives the third intensity signal from the third light receiving element (15). And comparing the third intensity signal with the third threshold, the third intensity signal exceeds the third threshold or the first intensity signal exceeds the first threshold, and the second 4. The optical sensor according to claim 1, wherein when the intensity signal exceeds the second threshold value, a lighting signal for turning on a headlight of the vehicle is output. 5. .   Until the third intensity signal exceeds the third threshold value when the third intensity signal is input from the third light receiving element (15) and the lighting signal is output from the determination circuit section (19). The light according to claim 4, further comprising a headlight luminance conversion circuit section (27) for increasing the luminance of the headlight of the vehicle (53) as the third intensity signal decreases. Sensor.   The first light receiving element (16), the second light receiving element (17), and the third light receiving element (15) are formed on one semiconductor chip (32). The optical sensor described in 1.

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