JPH0746910Y2 - Driving circuit for ECD anti-glare mirror - Google Patents

Description

[Detailed Description of the Invention] [Industrial application] The present invention relates to a drive circuit for an anti-glare mirror, and particularly for driving an ECD anti-glare mirror that determines the reflectance of an electrochromic device (ECD) in consideration of ambient light. It is about circuits.

[Prior Art] While driving a night car, when illuminated by the headlight of the following vehicle from behind, the rearview mirror reflects the light of the following vehicle's headlight,
This causes glare to the driver and interferes with safe driving, so that an image of high incident light that causes dazzling is changed to an image of low reflected light. For that purpose, the lever attached to the rearview mirror is manually operated to mechanically switch the reflection angle, or a circuit for automatically switching the reflection angle when light dazzling is incident is operated. In such a method of changing the reflection angle of the room mirror, the mirror is movably supported, and the reflection angle must be switched by a lever or a solenoid, so that the structure is complicated and the switching from high reflection light to low reflection light is performed. Cause a delay. Therefore, recently, by using a liquid crystal panel in which liquid crystal is sealed between glass substrates provided with transparent electrodes, the voltage applied to the electrodes of the liquid crystal panel is changed to change the light transmittance of the panel. Those that obtain an antiglare effect have been proposed.

[Problems to be solved by the invention] However, the mirror using the above liquid crystal panel has a variation in the transmittance of the liquid crystal panel and changes variously due to the influence of ambient temperature, aging, etc. It is difficult to maintain the transmittance at the set value even when applied. The color of the mirror of the liquid crystal panel varies depending on the viewing angle, resulting in a double image with poor visibility and insufficient weather resistance.
Therefore, it has been attempted to use the ECD panel as an antiglare mirror. Unlike LCDs, ECDs have good visibility, excellent contrast and light resistance, and also have a memory function. However, when an ECD panel is used as a mirror, a drive circuit suitable for the usage situation has not been developed. It was

An object of the present invention is to provide an ECD antiglare mirror drive circuit that allows a driver to switch the reflectance of the antiglare mirror by a switch operation without tilting the antiglare mirror. Another object of the present invention is to provide a drive device for an ECD anti-glare mirror that automatically sets the density of an electrochromic element to an intermediate density only when the surroundings are bright.

[Means for Solving the Problems] In order to achieve the above object, in an anti-glare mirror using an all-solid-state electrochromic device (ECD) type panel, coloring and erasing of the ECD panel are performed. A power supply for color voltage, a power supply for intermediate density coloring voltage for coloring the ECD panel to an intermediate density, a rear light determination circuit for detecting a rear light level and comparing with a reference voltage, and outputting the result, an ambient light A day and night determination circuit that detects the light level and compares it with the reference voltage to output the result,
When the judgment results from the rear light judgment circuit and the day / night judgment circuit are input, respectively, and when the day / night judgment circuit judges that it is “day”, a predetermined signal is output regardless of the judgment result from the rear light judgment circuit. Further, when the day / night judgment circuit judges that it is “night”, a gate circuit which outputs a signal of the same level as the judgment result from the rear light judgment circuit, and the coloring by the signal from the day / night judgment circuit And enabling power supply to the ECD panel by selecting either the power source for the erasing voltage or the power source for the intermediate density coloring voltage,
And a switching circuit for reversing the connection state between the ECD panel and the power supply in response to a signal from the gate circuit to switch the ECD panel to a colored or decolored state.

[Embodiment] Next, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram of a drive circuit of an ECD antiglare mirror according to the present invention, and FIG. 2 is a sectional view of an ECD panel.

In the figure, reference numeral 1 is an ECD (electro chromic
Device). This ECD 1 has an electrode layer 3 made of a transparent conductive film on a glass 2 as shown in the enlarged cross section of FIG.
EC layer 4 which is a coloring layer, electrode layer 5 which is an A1 layer, sealing resin layer 6 which is an insulating layer are laminated, and a glass 7 is laminated to form a thin panel shape, and the glass 7 side is a mirror support. It is fixed to (not shown) by adhesion or caulking.

When a coloring voltage is applied to the electrode layer 3, the mirror reflectance decreases, and when an erasing voltage is applied to the electrode layer 5, the mirror reflectance increases.

In the anti-glare mirror drive circuit of the present invention, the electrode layer 3 and the electrode layer 5 of the ECD 1 are respectively connected to the switching circuit 10, and the switching circuit 10 has a power supply 12 for coloring and decoloring voltage, a power supply 13 for intermediate density coloring voltage, Back light determination circuit 15, gate circuit 18
And a day / night determination circuit 20 are connected respectively.

The rear light determination circuit 15 includes a rear light sensor 16 and a comparator 17, and the day / night determination circuit 20 includes a day / night determination sensor 21 and a comparator 22 including a knot circuit 23. Also, the rear light determination circuit
15 and the day / night determination circuit 20 are connected to the constant voltage circuit 11.

The switching circuit 10 includes transistors Tr _{1 to} Tr ₆ and a knot circuit 14.

The rear light sensor 16 is a photo sensor that detects a light level of a headlight of a following vehicle and converts the light level into an electric signal (voltage), and a comparator for determining whether the electric signal is higher or lower than a reference voltage.
Judging at 17. The day / night discrimination sensor 21 is a photo sensor that detects ambient brightness and converts it into an electric signal (voltage), and a comparator for determining whether the electric signal is higher or lower than a reference voltage.
It is judged at 22.

The judgment results of the comparator 17 and the comparator 22 are gate circuits.
Input to 18 for logical judgment. This gate circuit 18
NOR gate 18a and inverter 18b, NOR gate 18a
When (H) is input to either terminal of
The output from b is (H).

The signal from the comparator 22 is input to the gate of the first transistor Tr ₁ and, after being level-inverted via the knot circuit 23, is input to the gate of the second transistor Tr ₂ .

For example, when the signal level of the comparator 22 is (L), the first
So that the (L) level signal is input to the transistor Tr _{1 of} , and the relevant Tr ₁ is “OFF”, and the (H) level signal is input to the second transistor Tr ₂ so that the relevant Tr ₂ is “ON”. Then, the power supply 12 for coloring and erasing voltage is selected.

The signal level output from the gate circuit 18 is the comparator
When a signal having the same level as the signal level output from 17 is output to the switching circuit 10 and the signal level from the comparator 17 is (H), the transistors Tr ₃ and Tr ₆ are “ON”, the transistor Tr ₄ , Tr ₅ “OFF”, the potential of A terminal of ECD1 becomes the potential of C point, and the potential of B terminal becomes the ground potential. Note that the comparator
The opposite is true when the signal from 17 is (L).

On the other hand, when the signal level from the comparator 22 is (H), the (H) level signal is input to the first transistor Tr ₁ and the Tr ₁ is turned “ON”, and the second transistor Tr ₂ is turned on. A (L) level signal is input to the Tr ₂ and the Tr ₂ is turned “OFF” to select the intermediate density coloring voltage power supply 13.

The signal level output from the gate circuit 18 is the comparator
Regardless of the signal from 17, it is always (H), transistors Tr ₃ and Tr ₆ are “OFF”, and transistors Tr ₄ and Tr ₅ are “O”.
N ”, the A terminal of ECD1 is grounded, and the B terminal is at the potential at point C.

Next, the operation of this embodiment will be described in detail.

When headlight light is emitted from a rear vehicle while traveling, the rear light sensor 16 detects the light level, converts it into an electric signal (voltage), and outputs it to the comparator 17. The comparator 17 compares and judges the electric signal with the reference voltage, and outputs the judgment result to the gate circuit 18. For example, when the electric signal is larger than the reference voltage, that is, when the headlight is dazzling, the comparator 17 outputs the signal (L), and in the opposite case, the signal (H) is output.

Further, the surrounding light and darkness, that is, "day" and "night" are detected by the day / night discrimination sensor 21, converted into an electric signal and input to the comparator 22, and compared with the reference voltage to judge "day" or "night". .
For example, when it is determined to be "night", the comparator 22 outputs the signal of (L), and conversely, when it is determined to be "day", the signal of (H) is output.

Therefore, when the signal level from the comparator 22 is (H), that is, when the comparator 22 determines "day", the output of the gate circuit 18 becomes (H) regardless of the signal level of the comparator 17,
The ECD 1 is driven by the intermediate density coloring voltage power supply 13 to attain the intermediate density regardless of the determination result of the light level of the headlight.

On the other hand, when the signal from the comparator 22 is (L), that is, the comparator 22
When it is determined to be “night”, a signal having the same level as the signal level of the comparator 17 is output, and the ECD 1 is driven by the coloring and decoloring voltage power supply 12. At this time, if the rear light is dazzling, the comparator 17 outputs the (H) level and the gate circuit
The signal level from 18 becomes (H). As a result, the A terminal of the ECD 1 is colored from the ground potential to the potential of the coloring and decoloring voltage power supply 12. When the rear light becomes dazzling, the signal level from the comparator 17 becomes (L), the A terminal of the ECD1 becomes the ground potential, and the color disappears.

As described above, the driving circuit according to the present invention automatically sets the color density of the ECD to an intermediate density when the ambient light is bright, and when the ambient light becomes dark, the ECD color density is changed according to the headlight of the following vehicle. The colored (anti-glare) state and the decolored (non-glare) state are automatically switched.

In the anti-glare mirror driving device of this embodiment, the photo sensor is used as the rear light sensor and the day / night sensor, but the present invention is not limited to this.

[Advantage of Invention] According to the above invention, when the ambient light is dark, the coloring density (reflectance) can be automatically switched according to the brightness of the headlight of the following vehicle, and the driver is dazzled by the headlight of the following vehicle. When the ambient light is bright (in the daytime), it is automatically set to an intermediate density to soften the glare and distinguish it from a normal mirror.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a driving device of an ECD antiglare mirror of the present invention, and FIG. 2 is a sectional view of an electrochromic device (ECD) used in the antiglare mirror of the present invention. 1 ... ECD, 10 ... switching circuit, 13 ... power source for intermediate density coloring voltage, 15 ... rear light judging circuit, 20 ... day / night judging circuit.

Claims (1)

[Scope of utility model registration request] 1. An all-solid-state electrochromic device (EC
In an anti-glare mirror using a D) type panel, a coloring and decoloring voltage power supply for coloring or erasing the ECD panel, an intermediate density coloring voltage power supply for coloring the ECD panel at an intermediate density, and a rear A rear light determination circuit that detects the light level and compares it with the reference voltage, and outputs the result; and a day and night determination circuit that detects the ambient light level, compares and determines the result with the reference voltage, and outputs the result. When the judgment results from the rear light judgment circuit and the day / night judgment circuit are input, respectively, and when the day / night judgment circuit judges that it is “day”, a predetermined signal is output regardless of the judgment result from the rear light judgment circuit. Further, when the day / night judgment circuit judges that it is “night”, a gate circuit which outputs a signal of the same level as the judgment result from the rear light judgment circuit and a signal from the day / night judgment circuit are output. It is possible to supply power to the ECD panel by selecting either the coloring and decoloring voltage power source or the intermediate density coloring voltage power source, and the ECD panel and the power source by the signal from the gate circuit. An ECD anti-glare mirror drive circuit, comprising: a switching circuit that reverses the connection state of and switches the ECD panel to either a colored state or a decolored state.