JPS643697Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vehicle light switching device that automatically turns on or off vehicle lights according to the ambient brightness detected by an illuminance sensor.

As a conventional vehicle light extinguishing device, there is one shown in FIG. 1, for example.

In FIG. 1, reference numeral 1 denotes an illuminance sensor that outputs a detection signal according to the ambient brightness obtained through the windshield 2. For example, a photodiode is used as the illuminance sensor 1, and the illuminance sensor 1 outputs a detection signal according to the ambient brightness obtained through the windshield 2. It is installed on the upper surface of the instrument panel 3, which is susceptible to changes. The output of the illuminance sensor 1 is given to a command circuit 4, which turns on the headlamp 5 and small lamp 6 when the detected illuminance falls below a specified value, and turns them off when the detected illuminance exceeds the specified value. This eliminates the need to operate a lighting switch depending on the surrounding brightness, making driving operations easier when driving in tunnels at night or during the day (Japanese Patent Laid-Open No. 56-31841).

However, such conventional vehicle light switching devices detect only the brightness above the vehicle through the windshield, so for example when driving under an elevated road along an elevated road. There was a problem in that when the vehicle stopped temporarily under a short overpass, etc., the light from above was blocked even though the road ahead was bright, causing the lights to turn on.

The present invention was developed in view of these conventional problems, and aims to prevent the lights from being turned on unnecessarily even when the front visibility of the vehicle is secured. .

To achieve this objective, the present invention includes a front illuminance sensor that is equipped with a polarizing filter that transmits light from the front of the vehicle and detects only the front illuminance, and a polarizing filter that transmits light from above the vehicle that detects only the upward illuminance. It is composed of an upper illuminance sensor that detects the illuminance, and a command circuit that instructs to turn on the vehicle lights when the illuminance detected by both the front illuminance sensor and the upper illuminance sensor is below a specified value.

Hereinafter, the present invention will be explained based on the drawings.

FIG. 2 is a circuit block diagram showing an embodiment of the present invention together with an illumination sensor mounting structure. First, the configuration will be described. On the upper surface of the instrument panel 3, which is inside the windshield 2, a sensor duct 7 and a sensor duct 8, which open substantially diagonally upward, are provided adjacent to each other.

The opening of the sensor duct 7 is equipped with a polarizing filter 21 that transmits only light from the front of the vehicle, and the bottom of the sensor duct 7 is equipped with a photodiode 9 as a front illuminance sensor. The photodiode 9 may make false detections due to the light from the headlights of an oncoming vehicle when driving at night, so in order to prevent such false detections, the direction of the light that passes through the polarizing filter 21 and enters the photodiode 9 is adjusted. A polarizing filter 21 is installed so that the light enters from below the left front, which is the opposite side of the oncoming lane.

On the other hand, the opening of the sensor duct 8 is provided with a polarizing filter 22 that transmits only light from above the vehicle, and the bottom of the sensor duct 8 is provided with a photodiode 10 as an upper illuminance sensor. Each of the photodiodes 9 and 10 is biased by the power supply voltage plus Vc through a resistor R, and as the amount of light incident on the photodiodes 9 and 10 increases, the current flowing through the photodiodes 9 and 10 increases, and the resistance R and photodiode 9,
The detection voltage at the connection point with 10 is a detection voltage that decreases as the illuminance increases. The detection outputs of the photodiodes 9 and 10 are given to a command circuit 13.

The command circuit 13 has an AND gate 14 to which the detection outputs of the photodiodes 9 and 10 are connected, and the output of the AND gate 14 is connected to the set terminal S of the RS flip-flop 16 via a time constant circuit 15.
The detection output of the photodiode 10 for detecting the upward illumination is connected to the RS flip-flop 1 via an inverter 17 and a time constant circuit 18.
The input terminal is connected to the reset terminal R of No. 6. The Q output of the RS flip-flop 16 is supplied to the headlamp 5 and small lamp 6 as a command output. Of course, the Q output of the RS flip-flop 16 does not directly drive the head lamp 5 and the small lamp 6, but the head lamp 5 and the small lamp 6 can be turned on and off by operating a relay contact or the like using a drive circuit (not shown). It is.

Also, the sensor ducts 7 and 8 on the top of the instrument panel
As the photodiodes 9 and 10 provided in the photodiodes 9 and 10, elements having the highest detection sensitivity to sunlight are used.

Next, the operation of the embodiment shown in FIG. 2 will be explained.

First, like when driving during the day, use polarizing filter 2.
1 and 22 to photodiodes 9 and 10,
When a sufficient amount of light is incident from the front and above, a sufficient current flows through the photodiodes 9 and 10 through the resistor R, and the detection outputs of the photodiodes 9 and 10 to the command circuit 13 are approximately in the vicinity of O volts. Therefore, both inputs of the AND gate 14 become L level, and the AND gate 14
The output of is also at L level. At this time, inverter 1
7 inverts the L level input from the photodiode 10 to generate an H level output, and on the condition that this H level output continues for more than the set time of the time constant circuit 18, the reset terminal R of the RS flip-flop 16 is activated. By resetting the RS flip-flop 16, it becomes Q=L level and the head lamp 5 and small lamp 6 are turned off.

Next, at night when the amount of light incident on the photodiodes 9 and 10 from the front and above is reduced,
Since the photodiodes 9 and 10 are almost in the OFF state, both inputs to the AND gate 14 of the command circuit 13 are at the H level. As a result, the AND gate 14 produces an H level output, which sets the RS flip-flop 16 via the time constant circuit 15, and Q=H.
When the level reaches this level, the head lamps 5 and the parking lamps 6 are turned on.

Furthermore, during daytime driving, the amount of light from above on the photodiode 10 decreases due to driving along an elevated road, etc., and the detected voltage falls below the threshold level of the AND gate 14, that is, the power supply voltage +
If it exceeds approximately 1/2 of Vc, the detection output of the photodiode 10 becomes an H level input to the AND gate 14. However, since the detection output of the photodiode 9 that detects the forward illuminance is at the L level, the output of the AND gate 14 is fixed at the L level, and even if the light from above is blocked, the headlamp 5 and The small lamp 6 is not lit.

Further, sensor ducts 7 and 8 are installed close to each other on the upper surface of the instrument panel 3, and each includes a polarizing filter 21 that transmits light from the front of the vehicle and a polarizing filter 22 that transmits light from above the vehicle. Since the front and upper illuminances are detected separately, there is no need to open the sensor ducts 7 and 8 forward and upward, respectively, and the installation space for the illuminance sensor can be saved.

Note that although the above embodiments have been exemplified by using a photodiode as the illuminance sensor, it goes without saying that other phototransistors, CdS, etc. may also be used.

As described above, according to the present invention, in a vehicle light switching device that automatically turns on or off vehicle lights based on the surrounding brightness detected by an illuminance sensor, the illuminance in front of the vehicle and the vehicle The illuminance above is detected individually by the illuminance sensor, and the vehicle lights are instructed to turn on only when both detected illuminances are below the specified value. Even if only the light from above is blocked by temporarily stopping under a narrow overpass, the vehicle lights will not turn on when the illuminance ahead is above the standard value, resulting in unnecessary vehicle lights while driving. It is possible to control the lighting of vehicle lights with high reliability by preventing the lights from turning on.In addition, the illuminance in front and above can be detected separately by using polarizing filters with different incident directions. There is no need to open the sensor ducts on the instrument panel toward the front and upwards, and the effect is that the installation space for the illuminance sensor can be saved.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing a conventional example, and FIG. 2 is a circuit block diagram showing an embodiment of the present invention together with the structure of an illuminance sensor. 2...Windshield, 3...Instrument panel, 5...Head lamp, 6...Small lamp, 7, 8...Sensor duct, 9...Photodiode (for forward detection), 10...Photodiode (upward detection) ), 13...command circuit, 14...
AND gate, 17... Inverter, 15, 18
...Time constant circuit, 16...RS flip-flop,
20...OR gate, 21...Polarizing filter (for transmitting light from the front), 22...Polarizing filter (for transmitting light from above).

Claims (1)

[Scope of claim for utility model registration] A forward illuminance sensor that is equipped with a polarizing filter that transmits light from the front of the vehicle and detects only the front illuminance, and an upper illuminance sensor that is equipped with a polarizing filter that transmits light from above the vehicle that detects only the upward illuminance. A vehicle light switching device comprising: an illuminance sensor; and a command circuit that instructs the vehicle lights to turn on when the illuminance detected by both the front illuminance sensor and the upper illuminance sensor is below a specified value.