JPH03254B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic light control device that automatically turns on and off the lights of an automobile according to outside light.

2. Description of the Related Art Devices are known that automatically turn on or off headlights, taillights, or side lamps depending on the outside light environment while driving. FIG. 5 shows a conventional device of this type, which has an external light sensor a that detects external light and sends out an output signal according to the external light, and a distance sensor b. The output signal from a is level-matched by a first comparator f, which compares its level with a reference value, and a second comparator g, and when it is necessary to turn on the headlights, a gate is applied. The headlight lighting circuit c is driven through the circuit h, and at this time, the output signal of the second comparator g drives the side lamp and tail light lighting circuits d and e through the gate circuit i. It's like this. On the other hand, in an environment where the headlights cannot be turned on, an output signal appears only in the second comparator g, and the lighting circuits d and e operate to turn on the sidemarkers and taillights. Furthermore, taking into consideration things such as entering a tunnel during daytime driving, if a change in the output signal of external light sensor a that exceeds the set value occurs within a predetermined driving distance, the headlights, sidemarker lights, and taillights will be turned off. It is set to turn on. j is a detection circuit for the output signal of external light sensor a;
k is the output signal of the detection circuit j and the distance sensor b
This gate circuit is designed to obtain a signal from the gate circuit, and its output is sent to the gate circuits h and i, so that the lighting effect can be obtained even if the vehicle enters a tunnel etc. during the daytime. It was designed so that

In this way, although it has the function of automatic light control, there are aspects that do not match the actual situation. For example, at night, while driving in a bright environment with a lot of external lighting, such as in a tunnel, the external light sensor a will work and turn off the headlights, or will not respond to instantaneous changes in external light to prevent malfunctions. Since the operating range is widened and the vehicle is required to travel a certain distance, if the vehicle enters a tunnel during daytime, the power to the headlights will be delayed and remain unlit for a while.

The present invention has been made in order to deal with such circumstances, and provides an automatic light control device that can provide control effects that are adapted to the driving environment.

Hereinafter, a detailed explanation will be given according to the illustrated embodiment.
In Fig. 1, 1 is an external light sensor such as a photodiode whose current increases or decreases depending on the external light, and 2 is a current-voltage conversion circuit that detects changes in the current of the optical sensor 1 as changes in voltage. The voltage comparator 2a and the resistor _R1 have the function of
Reference numeral 3 denotes a level comparison circuit, which is composed of a buffer circuit 3a and two voltage comparison circuits 3b and 3c. The buffer circuit 3a has the function of sending the voltage signal of the current-voltage conversion circuit 2 to the voltage comparison circuits 3b and 3c, and the voltage comparison circuit 3b has the function of sending the voltage signal of the current-voltage conversion circuit ₂ to the voltage comparison circuits 3b and _3c . The voltage comparison circuit 3c has the function of comparing the voltage signal with the voltage signal and sending out the first drive signal when the voltage signal becomes less than the reference voltage, and the voltage comparison circuit 3c is set by resistors R ₄ and R ₅ . It has the function of comparing a reference voltage with the voltage signal and sending out a second drive signal when this voltage signal is no longer lower than the reference voltage. Note that the reference voltage of the voltage comparison circuit 3b is set higher than the reference voltage of the voltage comparison circuit 3c. This is because, as will be clear from the explanation that follows, the first drive signal is for lighting the taillights and sidemarker lights, and the second drive signal is for driving the headlights. When the second drive signal is sent out, the first drive signal is also sent out at the same time.

4 is an AC amplifier circuit, which includes a buffer circuit 4a that obtains the voltage signal from the current-voltage conversion circuit 2, a capacitor c ₁ that cuts the DC component of the output signal,
It also includes an amplifier circuit 4b. The AC amplifying circuit 4 is added so that it can also respond when the external light sensor 1 detects external light from a fluorescent lamp, sodium lamp, etc. that involves alternating current changes.

Reference numeral 5 designates an AC detection circuit, which is comprised of a voltage comparison circuit 5a that compares the AC voltage signal from the AC amplifier circuit 4 with a reference voltage set by resistors R ₆ and R ₇ , and the AC voltage signal is the reference voltage. It has the function of sending out a third drive signal that turns on the tail lights, side marker lights, and headlights when the voltage exceeds (or falls below) the voltage.

Reference numeral 6 denotes a microcomputer, which receives the first and second drive signals from the level comparison circuit 3 and the third drive signal from the AC detection circuit 5, and when the first drive signal is added. When an output signal appears at the output terminal 6a and a second drive signal is applied, the output terminals 6a and 6b
Similarly, when the third drive signal is applied to both of the output terminals 6a and 6b, output signals appear at the output terminals 6a and 6b. In addition, the microcomputer 6
The operation is as follows for the third drive signal. That is, this drive signal includes, for example, an instantaneous pulse detected by the external light sensor 1 when the vehicle momentarily enters behind an object while driving, and a commercial power source for a fluorescent lamp or discharge lamp detected near or inside a tunnel. In the former case, the output terminals 6a and 6b
It operates so that an output signal is not sent to either of the two, and when the latter continuous pulse is obtained, an output signal is obtained at the output terminals 6a and 6b. In other words, it has the effect of preventing malfunctions caused by noise signals.

Reference numeral 7 is a relay drive circuit, and is composed of an amplifier 7a that amplifies the output signal from the output terminal 6a, and an amplifier 7b that amplifies the output signal from the output terminal 6b, and the amplifier 7a is excited by the output signal.
A relay circuit 8 is connected to close the energizing path to a load 10 such as a taillight or a sidemarker light, while a load 11 consisting of a headlight is excited by the output signal of the amplifier 7b.
A relay circuit 8 is connected to close the energization path to.

Therefore, depending on the driving environment, the load 10, 11
can be controlled as follows. The details will be explained with reference to FIGS. 2 and 3. The external light changes as shown in FIG. 2A, and the current value of the external light sensor 1 that detects this external light changes, and this current Is is converted into a voltage signal by the current-voltage conversion circuit 2. As shown on the vertical axis, it appears as the product of the value of resistance _R1 and the previous current value. Furthermore, similar characteristics can be obtained even under an environment in which illumination light is added to outside light (see FIG. 2B). Therefore, when the voltage signal of the current-voltage conversion circuit 2 becomes less than the value of each part set by the level comparison circuit 3, for example, when it becomes less than the reference voltage of the voltage comparison circuit 3c, the voltage signal of the voltage comparison circuit 3b, 3c is inverted and a first drive signal and a second drive signal are sent out,
As a result of the operation of the microcomputer 6, an output signal appears at the output terminals 6a, 6b, and the relay drive circuit 7 operates to excite the relay circuits 8, 9, close their contacts, and energize the loads 10, 11. Plan. On the other hand, the external light sensor 1 detects external light, and the voltage signal from the voltage-voltage exchange circuit 2 is transmitted to the voltage comparison circuit 3b,
When the reference voltage 3c is exceeded, the output level is reversed to its original level, the first and second drive signals are no longer sent out, and as a result, power supply to the loads 10 and 11 is stopped. However, when the voltage signal is approximately between the reference voltages of the voltage comparison circuits 3b and 3c, only the load 10 is energized, and the load 11 is de-energized. This is an environment where it is not necessary to turn on the headlights at dusk, but it is necessary to turn on the taillights and side lights.

Next, we will explain how to prevent malfunctions when the vehicle passes through instantaneous objects during daytime driving, and how it operates when the vehicle enters a tunnel.

When the vehicle passes through an object or enters a tunnel, the external light sensor 1 detects changes in the surrounding external light, and the current-voltage conversion circuit 2 receives the signal shown in Figure 3 according to the driving environment. The output voltage shown in appears. Here, the horizontal axis is the driving practice environment, where point A is when the vehicle passes the object, point B is near the entrance of the tunnel, and point C is the point where the vehicle passes the shadow.
The point is a place inside the tunnel where there is no outside light and the only illumination is inside the tunnel. Immediately before point B, outside light and lighting inside the tunnel are added, and from point B to point C, both outside light and lighting are detected. On the other hand, the AC amplifier circuit 4 cuts off the DC component of the output voltage shown in FIG. 3A, and the amplifier circuit 4b amplifies the AC component. The alternating current component referred to here is caused by the lighting cycle (100Hz or 120Hz) of the tunnel lighting such as fluorescent lamps and sodium lamps that are turned on by commercial power from point A or near the tunnel entrance until passing through the tunnel. It refers to what appears (see Figure 4).

Then, the AC voltage signal from the AC amplifier circuit 4 is sent to the AC detection circuit 5 and compared with a set reference voltage V ₁ (see FIG. 3B), and the reference voltage V _{1 is}
When it is above (or below), the pulse wave shown in FIG. 3C is sent out. The microcomputer 6 receives this pulse wave and sends output signals to the output terminals 6a and 6b, but the condition is that the pulse wave is counted a certain number of times. For example, when a pulse wave is received, a timer is started at the rising edge of the wave, and the number of pulses is counted per unit time, or the rising time of the next pulse is counted multiple times. This is an effective means for preventing malfunctions such as when the external light sensor 1 detects when the vehicle passes an object and drives the load. In places equipped with a light source, the lighting cycle is detected near the entrance of the light source, so the load can be driven without delay, and even if the internal lighting is bright, the load can be cut off in response. Nor.

Based on the above conditions, the microcomputer 6 sends output signals to its output terminals 6a and 6b to drive the loads 10 and 11 even when the first and second drive signals do not appear.

Although the above explanation has been about counting pulse waves or counting rise times using the microcomputer 6, it is also possible to install a band pass filter or high pass filter before the AC detection circuit 5 to select only a specific AC wave. It's okay. In this way, it becomes easy to distinguish between lighting with a constant lighting cycle, such as in a tunnel, and other noise.

As explained above, the automatic light control device for a vehicle according to the present invention turns on or off the loads of the taillight, sidemarker light, and headlight of the vehicle according to external light, and further turns on the load in a tunnel with lighting. This automatic light control for a vehicle includes a plurality of level comparison circuits that emit first, second, and third drive signals based on voltage changes accompanying changes in lighting detected by an external light sensor, and also means for detecting a lighting cycle of illumination light with a lighting cycle of , the first drive signal is a signal for lighting a tail light and a side marker light, and the second and third drive signals are a signal for lighting a tail light and a side marker light. and a signal to turn on the headlight, and the third drive signal is configured to control the lighting of the load using a periodic signal obtained by the means for detecting the lighting period as the drive signal, When the surrounding environment becomes a certain level of darkness, the first drive signal turns on the taillights and sidemarker lights even if there are no second and third drive signals, and when it gets even darker, the third drive signal turns on. Even if there is no drive signal, the headlights are turned on by the second drive signal, and even if the surrounding area becomes artificially bright due to entering a street light or tunnel, the third drive signal is output, Each lamp continues to be lit, and in particular, the third drive signal detects the lighting cycle, that is, the frequency, rather than the illuminance level.
Unlike the AC component included in the conventional illuminance level, there is no detection of pseudo AC components, and the excellent effect is that light control can be performed accurately under any environment.

[Brief explanation of the drawing]

Figure 1 is a block circuit diagram of the device of this invention;
Figure A is a voltage change characteristic diagram in response to changes in the brightness of outside light, B is a voltage change characteristic diagram in response to changes in brightness of outside light and lighting, and Figure 3 A, B, and C are output signals of the main parts in Figure 1. FIG. 4 is a lighting period characteristic diagram of the tunnel lighting, and FIG. 5 is a block diagram of a conventional device. DESCRIPTION OF SYMBOLS 1... External light sensor, 2... Current-voltage conversion circuit, 3... Level comparison circuit, 4... AC amplifier circuit, 5... AC detection circuit, 6... Microcomputer, 7... Relay drive circuit, 8, 9... Relay circuit, 10, 11... Load.

Claims (1)

[Claims] 1. An automatic light control device for a vehicle that turns on or off the taillights, sidemarker lights, and headlights of the vehicle according to outside light, and also turns them on in a tunnel with lighting, which uses an outside light sensor. The present invention includes a plurality of level comparison circuits that emit first, second, and third drive signals based on a voltage change accompanying a change in illuminance detected by the device, and means for detecting a lighting cycle of illumination light that has a constant lighting cycle. The first drive signal is a signal for turning on a tail light and a sidemarker light, the second and third drive signals are signals for turning on a taillight, a sidemarker light and a headlight, and the third drive signal is a signal for turning on a taillight, a sidemarker light and a headlight.
An automatic light control device for a vehicle, characterized in that the drive signal controls the lighting of the load using a periodic signal obtained by the means for detecting the lighting period as the drive signal.