JPH11344731A - Drive assembly of ec panel for rearview mirror - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drive assembly for an EC panel capable of embodying a fail-safe function and supplying an always stable voltage value to the EC panel. SOLUTION: A DC power source 1 is connected to a constant voltage circuit 2, to make the stable supply of the voltage possible. Further, a first switch 5 installed in a polarity inversion circuit 3 is turned on, by which forward voltage is impressed on the EC panel 4 to color the panel. Backward voltage is impressed on the EC panel by turning on a second switch 6, by which the resetting from a multicolored state to a decolored state is made possible. Further, when both of the first switch 5 and the second switch 6 are turned on in consequence of an erroneous operation, fault, etc., the input terminals Ta and Tb of the EC panel are shorted to each other and, therefore, the EC panel is thereby put into a decolored state (safe direction) and the fail-safe function can be exhibited.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrochromic panel (EC panel) mounted on a rearview mirror for a vehicle and capable of switching between an antiglare state and a return state by reversibly applying a DC voltage. The present invention relates to a driving device capable of stably supplying a voltage to an EC panel and exhibiting a fail-safe function.

[0002]

2. Description of the Related Art For example, when a vehicle such as a passenger car or a truck is driven at night, the headlight light from a following vehicle is reflected on a rearview mirror (inner mirror and outer mirror) and enters the driver's field of view. The driver may be dazzled by this light. Therefore, as a method of solving such a problem, a method in which an EC panel is conventionally attached to a glass substrate of a rearview mirror and a DC voltage is applied to the EC panel to reduce light reflectance and prevent dazzling. Has been devised and put to practical use.

As a conventional circuit for controlling an EC panel, for example, a circuit as shown in FIG. 2 is known, and a DC voltage from a DC power supply 12 is reversibly applied to an EC panel 11 shown in FIG. , The light reflectance can be reduced to achieve an anti-glare state (hereinafter referred to as a colored state) or to be restored (hereinafter referred to as a decolored state).

That is, a double switch 13 shown in FIG.
(13-1, 13-2) to operate the contacts 13-1c and 13-1
a, the contacts 13-2c and 13-2a are connected respectively,
When a voltage is applied to the panel 11 in the forward direction, the panel 11 becomes colored and an anti-glare effect can be obtained, and the switch 13 is reversed to contact the contacts 13-1c and 13-1b and the contacts 13-2c and 1-2.
When a voltage in the opposite direction is applied to the EC panel 11 by connecting each of the switches 3-2b to the EC panel 11, the operation returns to the decolored state, so that the driver can easily operate the switch 13 to easily reflect light. The rate can be changed, and dazzling due to the headlight light of the following vehicle at night can be prevented.

However, in the above-described conventional EC panel 11 and the driving circuit for applying a voltage to the EC panel 11, a double switch 13 is used to switch between coloring and decoloring. In such a case, the fail-safe function cannot be exhibited. More specifically, when the EC panel 11 is in a colored state and the light reflectance is reduced, the contact 13
When the trouble that the battery serving as a power source is exhausted and the battery does not operate occurs when the connection is restored to the decolored state by connecting the contacts -1c and 13-1b and the contacts 13-2c and 13-2b, the colored state is avoided. Can not do.

[0006] Comparing the safety when the rear-view mirror is in the colored state and when the rear-view mirror is in the decolored state, it is safer to be in the decolored state. When this occurs, it is desirable to be in the decolored state. However, in the conventional driving device for the EC panel 11 as described above, the battery may be fixed in a colored state when the battery is exhausted, which cannot be avoided and fail-safe cannot be realized. The problem had occurred.

The DC power supply 12 shown in FIG.
Normally, a 1.5 volt dry battery is used, so if the power supply voltage drops due to long-term use, the desired voltage value is reduced to E.
It may not be possible to supply to the C panel 11, and the response performance of the change in light reflectance may be degraded, so that it may not be possible to smoothly switch between coloring and decoloring.

[0008]

As described above, the conventional EC panel driving device does not have a fail-safe function, and thus, for example, when the battery is consumed due to aging, the EC panel 11 is colored. The trouble that it was fixed in the state where it was put on occurred. Also,
When the output voltage of the dry battery is reduced due to long-term use, the response of coloring and decoloring is deteriorated, and there is a disadvantage that the switching between coloring and decoloring cannot be performed smoothly. The present invention has been made to solve such a conventional problem, and an object of the present invention is to achieve a fail-safe function, and to always operate regardless of fluctuations in the output voltage of a dry battery. An object of the present invention is to provide an EC panel driving device capable of supplying a desired voltage.

[0009]

According to a first aspect of the present invention, there is provided a vehicle rearview mirror having input terminals Ta, Tb, and an input terminal Ta.
When a positive voltage is applied to the input terminal Tb, the terminal is colored.
When a and Tb are short-circuited, the color is erased.
Electrochromic panel (E
C panel), a DC power supply, a DC power supply, a first switch for applying a positive voltage from the DC power supply to the input terminal Ta side when the switch is turned on, and a switch on. And a second switch for applying a positive voltage from a DC power supply to the input terminal Tb side, and when both the first switch and the second switch are turned on, the input terminal Ta , T
b are connected so as to short-circuit each other, and when neither the first switch nor the second switch is turned on, the input terminal T
It is characterized in that the connection is made open between a and Tb.

According to a second aspect of the present invention, there is provided a rearview mirror for a vehicle, having input terminals Ta and Tb, coloring when a positive voltage is applied to the input terminal Ta side, When a positive voltage is applied to the Tb side, or when both input terminals Ta and Tb are short-circuited, the color is erased to control the coloring / erasing of the EC panel which can change the light reflectance. In the panel driving device, a DC power supply, a first switch that can selectively connect the input terminal Ta to a positive electrode or a negative electrode of the DC power supply, and the input terminal Tb are connected to a negative electrode of the DC power supply. Alternatively, a second switch that can be selectively connected to a plus electrode, and a second switch that is interposed between the first switch and the minus electrode of the DC power supply and that is activated when a plus voltage is applied to the input terminal Tb. Switching means, the first switch is connected to the positive electrode side when coloring, and the second switch is connected to the negative electrode side when coloring, and the first switch is connected to the negative electrode side when the color is erased. Are connected to the positive electrode side, respectively.

According to a third aspect of the present invention, a constant voltage circuit for controlling an output voltage to be constant is mounted on a subsequent stage of the DC power supply. The invention according to claim 4 is characterized in that the DC power supply is constituted by a lithium ion battery. According to a fifth aspect of the present invention, a first resistor (R1) is interposed at an arbitrary position on a current path when a positive voltage is applied to the input terminal Ta, and a positive voltage is applied to the input terminal Tb. A second resistor (R2) is interposed at an arbitrary position on a current path at the time of application.

According to the first and second aspects of the present invention configured as described above, it is possible to apply a positive voltage to the input terminal Ta side of the EC panel by turning on the first switch. Therefore, the EC panel can be in a colored state, and when the second switch is turned on, a positive voltage can be applied to the input terminal Tb side. be able to. In addition, the first switch, the second switch,
When both switches are turned on, the EC panel is in the decolored state (in a safer direction), so that the fail-safe function can be exhibited.

According to the third aspect of the present invention, since the constant voltage circuit is mounted on the subsequent stage of the DC power supply, even if the DC power supply is deteriorated due to long-term use, the EC panel is always fixed. Can be supplied. According to the fourth aspect of the present invention, since a lithium ion battery having extremely good temperature characteristics is used as a DC power supply, stable control of the EC panel can be performed without being affected by environmental changes. According to the fifth aspect of the present invention, the first resistor (R1) is interposed on the current path when the first switch is turned on to supply a positive voltage to the input terminal Ta side. The coloring speed can be adjusted by appropriately setting the magnitude of the resistance. Further, since the second resistor (R2) is interposed on the current path when the second switch is turned on to supply the positive voltage to the input terminal Tb side, the size of the second resistor is appropriately adjusted. By setting, the erasing speed can be adjusted.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a circuit diagram showing a configuration of an embodiment of a driving apparatus for an EC panel to which the present invention is applied. As shown in FIG.
, A constant voltage circuit 2 and a polarity inversion circuit 3, which are forward or reverse with respect to an EC panel (electrochromic panel) 4 installed on a mirror surface of a rearview mirror (outer mirror, inner mirror). Direction voltage is applied in the direction to control coloring and decoloring.

As the DC power supply 1, a dry battery is used. In this embodiment, a lithium ion battery (output voltage of 3.2 volts) having good temperature characteristics and capable of outputting a stable voltage especially at a low temperature is used. ing. Constant voltage circuit 2
Is connected to the DC power supply 1 through a parallel connection circuit of a first switch 5 and a second switch 6 described later, and reduces the voltage of 3.2 volts supplied from the DC power supply 1 to A constant DC voltage (for example, 1.5 volts) is always output without being affected by the change.

The polarity inversion circuit 3 includes two switches (first switch).
Switch 5) and the second switch 6).
Of the switch 5 is connected to one input terminal Ta of the EC panel 4, the contact 5a is connected to the positive electrode Tc of the constant voltage circuit 2, and the contact 5b is connected via a resistor R2 (second resistor). Transistor Q1 (switching means)
The emitter is connected to the negative electrode Td of the constant voltage circuit 2. On the other hand, the contact 6c of the second switch 6 is connected to the other input terminal Tb of the EC panel 4.
Is connected to the positive electrode Tc of the constant voltage circuit 2.
And the contact 6b is connected to a resistor R1 (first resistor)
Is connected to the negative electrode Td of the constant voltage circuit 2. Further, the contact 6c of the second switch 6 is connected to the base of the transistor Q1 via the resistor R3.

Each of the first switch 5 and the second switch 6 is a double switch. One of the switches is connected between the DC power supply 1 and the constant voltage circuit 2 as described above. It is installed in between. Then, the EC panel 4 operates to be colored when a positive voltage is applied to the input terminal Ta, and conversely, when a positive voltage is applied to the input terminal Tb, or between the two terminals Ta and Tb. When the is short-circuited, it operates to erase the color.

Next, the operation of this embodiment configured as described above will be described. The power supply voltage supplied from the DC power supply 1 is converted into a constant voltage value by the constant voltage circuit 2, and this voltage is generated between the plus electrode Tc and the minus electrode Td of the constant voltage circuit 2. Accordingly, the first switch 5 and the second switch 6 are both in an off state (off when connected to the contacts 5b and 6b side, and off when the contacts 5a and 6b are connected).
6a is referred to as off).
When the switch 5 is turned on, a current flows through the electrode Tc, the contact 5a, the contact 5c, the terminal Ta, the terminal Tb, the contact 6c, the contact 6b, the resistor R1, and the electrode Td. A positive voltage is applied to the side, whereby the EC panel 4 is colored. As a result, since the light reflectance of the rearview mirror is reduced, it is possible to prevent dazzling due to headlight light from a following vehicle during night driving. In this state, the first
Is turned off, the terminal T of the EC panel 4 is turned off.
Since the release state is established between a and Tb, the previous state is maintained, and in this case, the coloring state is continued.

Next, when the second switch 6 is turned on, a constant voltage is generated between the base and the emitter of the transistor Q1 via the electrode Tc, the contact 6a, the contact 6c, and the resistor R3. Since the emitters are electrically connected and the current flows through the electrode Tc, the contact 6a, the contact 6c, the terminal Tb, the terminal Ta, the contact 5c, the contact 5b, the resistor R2, the transistor Q1, and the electrode Td, the EC panel 4, a positive voltage is applied to the terminal Tb side, whereby the EC panel 4 is decolorized. As a result, the light reflectance of the rearview mirror returns to the original state. In this state, the second switch 6
Is turned off, the state between the terminals Ta and Tb of the EC panel 4 is released, so that the previous state is maintained. In this case, the decolored state is continued. Thus, by operating the first switch 5 and the second switch 6, E
Coloring and decoloring of the C panel 4 can be switched.

Here, when the operator operates the switch by mistake or when the first switch fails and is fixed to the ON state, both the first switch 5 and the second switch 6 are turned on. May be in a state. In this case, E
No voltage is applied between the terminals Ta and Tb of the C panel 4,
In addition, the two input terminals Ta and Tb of the EC panel 4 are short-circuited via the terminal Ta, the contact 5c, the contact 5a, the contact 6a, the contact 6c, and the terminal Tb. It will be in the decolored state.

From the above description, the connection states of the first switch 5 and the second switch 6 and the state of the EC panel 4 are summarized as follows (1) to (4). (1) When both the first switch 5 and the second switch 6 are off, the previous state is maintained. (2) When the first switch 5 is on and the second switch 6 is off, a colored state is set. (3) When the first switch 5 is off and the second switch 6 is on, the color is erased. (4) When both the first switch 5 and the second switch 6 are on, the color is erased.

That is, when both the first switch 5 and the second switch 6 are turned on due to an erroneous operation, a failure, or the like, the EC panel 4 is set to the decolored state (safe direction). , It is possible to achieve fail-safe, and even if a failure occurs, the driver can be sure that EC
Since the panel 4 can be switched from the colored state to the erased state, safety can be further improved.

Further, since the constant voltage circuit 2 is provided between the DC power supply 1 and the polarity inversion circuit 3, a constant voltage value is always supplied to the EC panel 4 regardless of the deterioration of the DC power supply. Therefore, stable response performance can be maintained. Further, the first switch 5 and the second switch 6
Are of the dual type, one of which is installed between the DC power supply 1 and the constant voltage circuit 2, so that both the first switch 5 and the second switch 6 are turned off. In this case, the connection between the DC power supply 1 and the constant voltage circuit 2 is cut off, the generation of dark current is prevented, and the power consumption of the DC power supply 1 can be suppressed.

As described above, when the EC panel 4 is colored, the current flows through the resistor R1, and when the EC panel 4 is erased, the current flows through the resistor R2. By appropriately changing the size of R2, EC
The coloring speed and the decoloring speed of the panel 4 can be individually adjusted. Further, in the present embodiment, a lithium ion battery is used as the DC power supply 1, and since the lithium ion battery has an excellent temperature characteristic as is well known, a stable voltage is always supplied without being affected by environmental changes. And the stability can be further improved. In the above-described embodiment, an example in which the junction type transistor Q1 is used as the switching means has been described. However, the present invention is not limited to this.
Similar effects can be obtained by using a thyristor, a relay, or the like.

[0025]

As described above, according to the driving apparatus of the EC panel of the present invention, the EC panel can be colored by turning on the first switch, and can be colored by turning on the second switch. The colored state can be returned to the erased state, and when both the first switch and the second switch are turned on due to a malfunction or the like, the state is erased. Therefore, a fail-safe function can be exhibited, and safety can be improved.

Also, by installing a constant voltage circuit on the subsequent stage of the DC power supply, a constant voltage can be supplied to the EC panel at all times. Therefore, even if the voltage value of the DC power supply drops due to aging. It is possible to stably switch between coloring and decoloring. Furthermore, if a lithium ion battery is used as the DC power supply, the temperature characteristics are improved, and a stable operation that is not affected by the ambient temperature can be secured. Further, by providing the first resistor R1 and the second resistor R2, it is possible to obtain an effect that the speed of coloring and decoloring can be appropriately set.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a configuration of an EC panel driving device according to an embodiment of the present invention.

FIG. 2 is a circuit diagram showing a configuration of a conventional EC panel driving device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1,12 DC power supply 2 Constant voltage circuit 3 Polarity inversion circuit 4,11 EC panel 5 First switch 6 Second switch 13 Double switch Q1 Transistor (switching means) R1 First resistor R2 Second resistor

Claims (5)

[Claims] An input terminal mounted on a rearview mirror for a vehicle and having input terminals Ta and Tb. When a positive voltage is applied to the input terminal Ta, the terminal is colored and a positive voltage is applied to the input terminal Tb. Alternatively, if the input terminals Ta and Tb are short-circuited, the color of the electrochromic panel (EC panel), which can change the light reflectance by erasing the color, is used to control the coloring and erasing of the EC panel. And a first switch that applies a positive voltage from the DC power supply to the input terminal Ta side when the switch is turned on, and applies a positive voltage from the DC power supply to the input terminal Tb side when the switch is turned on. And a second switch, wherein when both the first switch and the second switch are turned on, the input terminals Ta and Tb are connected so as to short-circuit, and If the switch and the second switch are not both turned on, the input terminals Ta, Tb between the drive device EC panel rearview mirror, characterized in that connected to be released. 2. The vehicle is mounted on a rearview mirror for a vehicle and has input terminals Ta and Tb, and is colored when a positive voltage is applied to the input terminal Ta, and a positive voltage is applied to the input terminal Tb. Alternatively, when the input terminals Ta and Tb are short-circuited, the color is erased when the EC terminal is capable of changing the light reflectance by erasing the color. A first switch capable of selectively connecting the input terminal Ta to a positive electrode or a negative electrode of the DC power supply; and selectively connecting the input terminal Tb to a negative electrode or a positive electrode of the DC power supply. A second switch to be obtained; and a switching means interposed between the first switch and the negative electrode of the DC power supply, and turned on when a positive voltage is applied to the input terminal Tb. When coloring, the first switch is connected to the positive electrode side, and the second switch is connected to the negative electrode side. When decoloring, the first switch is connected to the negative electrode side, and the second switch is connected to the positive electrode side. A driving device for an EC panel for a rearview mirror, wherein the driving device is connected to each of the above. 3. The EC panel for a rearview mirror according to claim 1, wherein a constant voltage circuit for controlling an output voltage to be constant is mounted on a subsequent stage of the DC power supply. Drive. 4. The apparatus according to claim 3, wherein the DC power source is a lithium ion battery. 5. A method in which a first resistor (R1) is interposed at an arbitrary position on a current path when a positive voltage is applied to the input terminal Ta, and a positive voltage is applied to the input terminal Tb. The EC for a rearview mirror according to claim 2, wherein a second resistor (R2) is interposed at an arbitrary position on the current path.
Panel drive.