JPH0531628Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial field of application] The invention relates to a vehicle anti-glare mirror.
The present invention relates to a drive circuit for an anti-glare mirror that performs anti-glare by varying the reflectance of the mirror depending on the brightness of headlight light emitted by a following vehicle.

[Conventional technology]

Conventional anti-glare mirrors for vehicles use a liquid crystal panel on the mirror surface, and a light sensor is attached to a part of the mirror housing.When strong light from a following vehicle is detected, the mirror surface becomes a low-reflection mirror. There are known devices that control voltage application (or voltage application cut-off) to improve the rate.

Furthermore, a configuration as shown in FIG. 3 is also known. Figure 3 shows a configuration that switches between anti-glare and non-dimming. In the figure, BT is a battery, CVC is a constant voltage circuit, EC is an electrochromism, A/1 is a relay with contact a, SW ₁ is a changeover switch. The same configuration is battery BT
The power supply is electro-voltage via the constant voltage circuit CVC.
By driving chromism EC, the reflectance of the mirror is made low. That is, normally the electrochromism EC is in a short-circuited state due to contact a of relay A/1, and by closing switch _SW1 , contact a is connected via constant voltage circuit CVC.
This applies a voltage to the electrochromism EC, causing the mirror surface to perform an anti-glare action, or so-called low reflectance.

[Problem that the invention attempts to solve]

However, in the case of an anti-glare mirror drive circuit that utilizes electrochromism (hereinafter referred to as EC), when the battery power is turned off,
EC is short-circuited and the switch is not turned on.
Closing SW ₁ switches from non-dimming to anti-dazzling mode, but while switch SW ₁ is closed and the anti-glare signal is being input, EC remains at a certain value. A constant DC voltage was applied continuously. Therefore, in terms of the durability of the EC, its lifespan is inversely proportional to the magnitude and time of the voltage applied to the EC, and the lifespan of the EC is short.

The present invention has been made by focusing on such conventional problems, and provides an EC drive circuit for an anti-glare mirror that can extend the life of the EC mirror without losing the characteristic features of EC. The purpose is to

[Means for solving problems]

The anti-glare mirror drive circuit of this invention consists of a constant voltage cut-off circuit that supplies a positive DC voltage to the EC mirror, and an EC
A switching circuit for switching between mirror dimming and non-dimming, an oscillation circuit that operates when switching to dimming, and a switching circuit that is driven and controlled by the oscillation output and supplies current to the EC mirror intermittently. and a trigger circuit that is activated during anti-glare control and generates a clock signal to the oscillation circuit.

[Effect]

The anti-glare mirror drive circuit configured as described above closes the anti-glare drive switch and drives the trigger circuit and oscillation circuit when the EC mirror is to perform anti-glare operation.
A switch circuit inserted into the EC mirror's current supply circuit controls the operation intermittently, and by utilizing the EC mirror's memory, it supplies current to the EC mirror while making the EC mirror's anti-glare function continuous. is operated intermittently.

〔Example〕

The present invention will be explained in detail below with reference to FIGS. 1 and 2. FIG. 1 shows a specific circuit configuration, and the same reference numerals as in FIG. 3 have the same functions. In Figure 1, 1 is a switching circuit that switches between anti-glare and non-dimming.
The series circuit of SW ₁ and relay A/1 is battery BT.
It is connected to. Reference numeral 2 denotes a trigger circuit that operates only when an anti-glare signal is input, and is composed of a capacitor C ₁ and a resistor R ₁ , and is configured to be supplied with power via a switch SW ₁ . 3 is an oscillation circuit, and 4 is a switching circuit driven by the oscillation circuit 3, which is a relay B/1. 5 is a DC voltage circuit that generates a certain positive value, and 6 is an EC mirror. The contact a of the relay A/1 and the contact b of the relay B/1 are inserted in series between the DC constant voltage circuit 5 and the EC mirror 6,
Switch SW ₁ is closed and relay A/1 is energized to put the EC mirror 6 in an anti-glare state,
The anti-glare state is canceled by energizing relay B/1. i.e. switch
After SW ₁ is closed, relay B/1 is intermittently excited by the circuit function of oscillation circuit 3, and the current supplied to EC mirror 6 is intermittently controlled by switching contact b. be.

Next, the operation of the circuit will be explained. First, the switch
When SW ₁ is in the open state, it is in the connected state shown in Figure 1, but the OX terminal of EC mirror 6 is connected to contacts b and a.
It is connected to the RE terminal via (short-circuited state).
In this state, the reflectance of EC mirror 6 is high (bright)
(This state is the non-dazzling state of the mirror.)

Next, when switch SW ₁ is closed, relay A/1 is energized, its contact a is switched to the NO side, and the OX terminal of the EC mirror 6 is connected to the CVC constant voltage circuit via contact b. On the other hand, since the RE terminal of the EC mirror is always connected to the ground terminal of the battery BT, the EC mirror 6 is energized and enters a low reflectance (dark) state (this state is the mirror's anti-glare state).

Then, when the switch SW ₁ is closed, the trigger circuit 2 and the oscillation circuit 3 including the capacitor C ₁ and the resistor R ₁ are put into operation at the same time as the above operation. Oscillation circuit 3
is an oscillator circuit that has a reset terminal CL in advance, and its output terminal Q outputs an "L" level while an "H" level signal is applied to the reset terminal CL. If switch _SW1 is closed, At the same time, the (+) potential of the battery BT is applied to the reset terminal CL via the capacitor _C1 .

Since C ₁ is a capacitor, for a certain time, that is, t ₁ =
After C ₁ ×R ₁ , the current stops flowing, and the CL terminal goes to the "L" level via the resistor R ₁ . CL terminal is “L”
When the level is reached, the oscillator 3 outputs an output that repeats "H" and "L" levels at a certain period to the Q terminal.
When the Q terminal of oscillator 3 is at "H" level, relay B/1 is energized and its contact b switches to the NO side,
The OX terminal of EC mirror 6 is open, and since relay B/1 is not excited when it is at the "L" level, its contact b becomes the NC side and is connected to the constant voltage circuit CVC via the NO side of contact a. . From then on, these steps will be repeated.

The pulse waveform in Figure 2 is generated by the switch as described above.
This is a time chart of the pulse current waveform applied to the EC mirror 6 from when SW ₁ is closed to when it is opened.

As you can see from these figures, EC mirror 6
Due to its nature, it has a memory like a capacitor, but if one or both ends are opened after energization, it will discharge slightly, so its potential will gradually decrease.
Furthermore, since the lifespan of the EC mirror 6 is inversely proportional to the voltage magnitude and time, while the anti-glare signal is being input, the OX terminal of the EC mirror 6 is repeatedly energized and open as described above. replenish and
The lifespan can be extended by shortening the energization time.

Note that in the above embodiment, the EC mirror 6
Although the case where the supply circuit for the pulse current applied to the circuit is configured by the trigger circuit 2, the oscillator 3, and the relay B/1 has been described, this is not limited to this, and the same effect can be obtained by using an electronic switch configuration using an integrated circuit.
It goes without saying that the effects can be obtained.

[Effect of idea]

As is clear from the above-mentioned embodiments, the anti-glare mirror drive circuit of the present invention includes a switching circuit for switching between dimming and non-dimming of the EC mirror, an oscillation circuit that operates when switching the anti-glare, and an oscillation circuit for the EC mirror. The EC mirror is driven by a switching output and is equipped with a switching circuit for intermittently supplying current to the EC mirror, and a trigger circuit that operates during anti-glare control and issues a clock signal to the oscillation circuit. The EC mirror can be driven intermittently while the anti-glare signal is being input by utilizing the memorability of the EC mirror.
There is no need to continuously supply current to the EC mirror,
The lifespan of the EC mirror can be significantly extended.

[Brief explanation of the drawing]

FIG. 1 is a driving circuit diagram of an anti-glare mirror showing an embodiment of the present invention, and FIG. 2 is a time chart for explaining the operation of the circuit shown in FIG. FIG. 3 is a drive circuit diagram of a conventional anti-glare mirror. 1, 4...Switching circuit, 2...Trigger circuit, 3
...Oscillation circuit, 5...DC constant voltage circuit, 6...
EC mirror, SW... switch, A/1, B/1...
…Relay, C…Capacitor, R ₁ …Resistance, a,
b...Relay contact.

Claims (1)

[Scope of utility model registration request] In the drive circuit of an electrochromism type anti-glare mirror, which performs anti-dazzle by varying the reflectance of the mirror according to the brightness of the headlight light emitted by the following vehicle, a certain positive a DC constant voltage circuit that supplies a DC voltage of , a switching circuit for intermittently supplying current to the electrochromic mirror, and a trigger circuit that operates during anti-glare control and issues a clock signal to the oscillation circuit, An electro-chromism drive circuit for an anti-glare mirror, characterized in that it is configured to intermittently supply current to the electro-chromism mirror during anti-glare drive.