JPH0640286A - Automatic lighting controller - Google Patents

Abstract

PURPOSE:To provide an automatic lighting controller which is mounted in an automobile so as to control lighting with brightness suited to the sensitivity of human eyes and without being affected by weather conditions. CONSTITUTION:The first IR sensitivity restraint type optical detector 11 and the second optical detector 12 provided with IR sensitivity are mounted to ccmpare the outputs from the first and second optical detectors with each other by the first comparator 15 and judge fine or rainy weather. Moreover, a switch circuit 16 is controlled by the output from the first comparator 15 to output a fine weather lighting level or a rainy weather lighting level according to comparative results and compare it with the output from the first optical detector 11 by the second comparator 19. The lighting level selected by the switch circuit 16 is used as a threshold to output a lighting-up or lighting-out command from the second comparator 19.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic turn-on / off control device for turning on and off an automobile headlight or the like according to the brightness of the surroundings and for turning off the light.

[0002]

2. Description of the Related Art Conventionally, an automatic lighting / extinguishing control device for detecting lighting of surroundings and controlling lighting of a headlight, a small light, and the like has been considered, and is actually installed in a vehicle. Such an automatic lighting control device is provided with a photodetector such as a silicon photodiode for detecting the ambient brightness, and when the ambient brightness of the photodetector becomes a predetermined value or less, The headlights are turned on.

However, when such automatic turn-on / off control is performed by detecting with a photodiode, the sensitivity of the human eye (visual sensitivity = illuminance) and the detection signal output from the photodetector match. Therefore, it is difficult to perform lighting control with the brightness required by humans. In particular, ordinary silicon photodiodes have a great sensitivity to infrared rays that are not visible to the human eye, and the photodiodes can be used when the skylight contains a large amount of infrared rays, such as when it is cloudy or rainy. The level of detection output from the diode increases.

As a countermeasure against such a point, it is considered to use a photodiode having a characteristic of suppressing infrared sensitivity, and to use an infrared cut filter. However, even if a photodiode with suppressed infrared sensitivity is used, the countermeasure effect cannot be sufficiently obtained, and since special parts are used in combination, the number of manufacturing steps increases, which causes a cost increase. . And in any case, it is not possible to deal with all weather conditions.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and lighting / extinction control corresponding to the sensitivity of human eyes is executed regardless of weather conditions such as fine weather or rainy weather. The present invention aims to provide a highly reliable automatic lighting control device.

[0006]

An automatic lighting / extinguishing device according to the present invention comprises a first light detecting means whose infrared sensitivity is suppressed and a second light detecting means whose infrared sensitivity is set,
The detection signals from the first and second light detecting means are compared with each other to judge the weather condition of fine weather or cloudy rain by weather judgment, and based on the judgment result of the weather judging means, the lighting level in fine weather or cloudy rain The threshold value for lighting / extinction control for selecting one of the hourly lighting levels is set.

[0007]

In the automatic turn-on / off control device constructed as described above, the detection output signal levels from the first and second light detecting means differ depending on whether it is fine weather or rainy weather, and the infrared rays in cloudy or rainy conditions. The level becomes higher, and the detection signal level from the second light detecting means becomes higher than the output from the first light detecting means. Therefore, by comparing the outputs from the first and second light detecting means, respectively, the weather conditions of fine weather and cloudy weather or rainy weather can be determined. Therefore, if a threshold value for lighting and extinguishing control is set based on this determination result, the lighting control and extinguishing control of the small light and the headlight are executed according to the sensitivity of the human eye. And its operational reliability is improved.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows the configuration of the first and second photodetectors 11 and 11 in order to detect ambient brightness.
12 is set. The first photodetector 11 is composed of a photodiode whose sensitivity is characteristically suppressed in the infrared wavelength region, and the second photodetector 12 is composed of a photodiode having sensitivity in the infrared wavelength region.

The first and second photodetectors 11 and 12
Are mounted and set at positions where they receive the skylight of the vehicle, respectively. The detection output signals from the first and second photodetectors 11 and 12 are amplified by amplifiers 13 and 14, respectively. Appropriate gain is set to be used to determine whether it is rainy or sunny.

The first and second photodetectors 11 and 12
The output signals from amplifiers 13 and 14, which are the outputs from
This comparator is the one to be compared in the first comparator 15.
15 becomes the fine weather determination unit 151.

Specifically, the output signal level from the first photodetector 11 whose sensitivity in the infrared wavelength range is suppressed is lower than the output signal level from the second photodetector 12 having sensitivity in the infrared wavelength range. If is smaller, a positive output signal is obtained from the comparator 15, and it is determined that the weather is fine. Conversely, the first photodetector
When the output signal level from 11 is large and the negative output signal from the comparator 15 can be changed, it is determined to be cloudy or rainy.

The comparison output from the comparator 15 is supplied to the switch circuit 16 as a switching command signal. The switch circuit 16 selects one of the signals from the lighting level setting section 17 in fine weather and the lighting level setting section 18 in rainy weather.
The level signal selected by the switch circuit 16 is supplied to the non-inverting side terminal of the second comparator 19. This second comparator
An output signal from the amplifier 13 to which the detection signal from the first photodetector 11 is supplied is supplied to the inverting terminal of 19.

That is, the comparator 19 compares the signal level selected by the switch circuit 16 with the output signal level of the first photodetector 11, and the output signal from the switch circuit 16 is a threshold value. Thus, the comparator 19 constitutes the light-on / light-off determination unit 191. Then, a command signal output for turning on and off is obtained from the second comparator 19 and supplied to a headlight control circuit (not shown).

In the device constructed as described above, the first
And a first comparing the outputs of the second photodetectors 11 and 12
The comparator 15 determines the amount of infrared rays contained in the skylight, and when it is determined that the amount of infrared rays is large, it is determined to be rainy weather, and vice versa.

FIG. 2A shows the state of the A output from the first photodetector 11 and the B output from the second photodetector 12 in fine weather. The light is turned on when the output falls below the threshold value b. In this figure, the shaded portion between the levels a and b, which is the brightness that can be visually perceived, is the infrared output.

On the other hand, in a cloudy or rainy state, the amount of infrared rays increases as shown in FIG. 2B, but the brightness perceived by the eyes is from a to a'in fine weather.
As shown in, it gets dark in rainy weather. However, the infrared output indicated by the diagonal lines is greatly different between fine weather and rainy weather. Therefore, the difference in the infrared light amount is determined by the fine weather determination unit 151, and the switch circuit 16 is controlled to control the lighting level during fine weather. One of the outputs from the setting unit 17 or the rain-lighting level setting unit 18 is selected. And FIG.
As shown in (C), the threshold value for lighting control in rainy weather is corrected to b ', and the apparent brightness a is made uniform in fine weather and rainy weather.

The apparatus shown in this embodiment comprises first and second photodetectors 11 and 12 each composed of two types of photodiodes having different wavelength sensitivities. Then, attention is paid to the fact that the wavelength characteristics of the external light are different between fine weather and rainy weather to judge whether it is fine rain or not.

Conventionally, only the infrared sensitivity type photodiode is used, and the output level thereof is compared with a set threshold value to control the turning on / off of the headlight. For this reason, due to the difference in infrared level, it is not turned on in rainy weather unless it becomes darker than in clear weather. Therefore, there is a gap at this point with the sense of the human eye.

However, as shown in the embodiment, if it is determined to be "rain" in the judgment of weather conditions of fine weather and rainy weather, the threshold value for judging whether the headlight is turned on or off is adjusted to You can close the gap with your sense of eyes.

FIG. 3A shows the structure of a photodiode with infrared sensitivity, and FIG. 4A shows the structure of an infrared sensitivity suppressing photodiode. And FIG.
4B shows spectral sensitivity characteristics of the photodiode with infrared sensitivity and the photodiode with suppressed infrared sensitivity. These photodiodes include a second photodetector 12 and a first photodetector 11 respectively.
And can be easily incorporated in each CMOS IC, and can be configured in the same chip without particularly increasing the number of chips.

FIG. 5 shows the output voltage characteristics of the first and second photodetectors 11 and 12 constituted by such photodiodes. The infrared sensitivity suppression type first photodetector 11 is shown in FIG. In the case of, the characteristic becomes as shown by A, and the output voltage decreases in the cloudy or rainy condition. On the other hand, in the case of the second photodetector with infrared sensitivity, the output voltage rises in the situation where the number of clouds increases as shown by the characteristic B. By comparing the output of 12 with the output of the first photodetector, the weather condition of fine weather or rainy weather is determined.

[0022]

As described above, according to the automatic turn-on / off control device according to the present invention, the threshold value of the lighting and turning-off control is corrected and set according to the weather condition, which corresponds to the sensitivity of human eyes. In this state, the headlight can be turned on / off. Therefore, the automatic lighting control of the small lights and the headlights of the automobile is executed in a state where sufficient reliability is obtained.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram for explaining an automatic turn-on / off control device according to an embodiment of the present invention.

2A to 2C are diagrams showing the output state of the photodetector in the lighting control state in the above embodiment.

FIG. 3A is a diagram showing the configuration of a photodiode with infrared sensitivity, and FIG. 3B is a diagram showing its spectral sensitivity characteristics.

FIG. 4A is a diagram showing the configuration of an infrared sensitivity suppression photodiode, and FIG. 4B is a diagram showing its spectral sensitivity characteristics.

FIG. 5 is a diagram showing the output voltage characteristics of the first and second photodetectors in comparison.

[Explanation of symbols]

11 ... 1st photodetector (infrared sensitivity suppression type), 12 ... 2nd photodetector (type with infrared sensitivity), 15 ... 1st comparator, 151 ...
A fine and rainy weather determination unit, 16 ... A switch circuit, 17 ... A fine weather lighting level setting unit, 18 ... A rainy lighting level setting unit, 19 ... A second comparison circuit, 191 ... A lighting on / off determination unit.

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[Procedure amendment]

[Submission date] September 7, 1993

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 3

[Correction method] Change

[Correction content]

[Figure 3]

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 4

[Correction method] Change

[Correction content]

[Figure 4]

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yushi Higuchi 1-1-1, Showa-cho, Kariya city, Aichi Nihon Denso Co., Ltd.

Claims (1)

[Claims] 1. Comparing the detection signals from the first photodetecting means whose infrared sensitivity is suppressed, the second photodetecting means whose infrared sensitivity is set, and the first and second photodetecting means. , Weather determining means for determining weather conditions in fine weather or cloudy weather, and lighting level selecting means for selecting one of the lighting level in fine weather or the lighting level in cloudy weather based on the determination result of the weather determining means. An automatic switch is characterized in that a level selected by the lighting level selection means is used as a threshold value, and a lighting or extinguishing command is issued based on a detection output of the first or second light detection means. Turn-on / off control device.