JPS63192024A - Method and circuit for driving ec glare-proof mirror - Google Patents

Abstract

PURPOSE:To prevent the degradation of an electrochromic EC element and related elements by using a staircase square wave voltage and a pulse interrupted voltage as the driving impression voltage for coloring and short-circuiting both terminals of the EC element at the time of achromatizing. CONSTITUTION:In a coloring process Tc, a staircase square wave voltage 1 whose value is reduced from VD to VS after a time tc1 is applied, and the high voltage VD is impressed in the initial stage and the impressed voltage is reduced to VS when coloring advances to a certain degree, and the EC element reaches a prescribed coloring density in the time Tc. After the EC element reaches the prescribed coloring density, a pulse interrupted voltage 2 having a crest value VS, a pulse width TD2, and a pulse interval TD1 is impressed in a coloring holding process. Both terminals of the EC element are short- circuited for a time T2 in the achromatizing process. Thee responsiveness of the element is improved in the coloring process and the pulse interrupted voltage is impressed in the coloring holding process and terminals are short-circuited at the time of achromatizing, thereby minimizing the degradation of the element to extent the life of the EC element.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention is an EC protection device that utilizes the electrochemical phenomenon of coloring and decoloring of electrochromic elements (hereinafter referred to as EC elements) to prevent dazzling of automobile mirrors caused by external light. The present invention relates to a glare mirror driving method and an EC anti-glare mirror drive circuit that implements the driving method.

More specifically, the present invention relates to a method for driving an all-solid-state EC element used in an automotive anti-glare mirror and a drive circuit for an EC anti-glare mirror that implements the driving method.

[Prior Art] The EC anti-glare mirror using the full rotation type EC element of the present invention is as follows:
A glass substrate, a transparent electrode, an insulating layer made of a dielectric film or a solid electrolyte film, one or more EC layers, and a counter electrode (Af
When a voltage is applied between the electrodes, an electrochemical reaction occurs, resulting in coloring or decoloring. The coloring and decoloring mechanism when WO3 is used in the EC layer, for example, is explained by the following redox reaction equation (11).

WO3+ x H” 10x e, -t H,X WO3
・==111 As shown in the above equation (1), coloration occurs due to the formation of tungsten bronze HX WO 3 , but if the applied voltage is then reversed, a richly colored state is obtained. In an all-solid-state EC device, such a reaction expressed by equation (1) is caused by the supply of protons H+ from H2O adsorbed on the insulating layer inside the device, resulting in coloration.

It is said that when the amount of H+ and OH generated by electrolysis of the electrolyte in the insulating layer during coloring exceeds the required level, gas is generated and causes deterioration of the EC element. Also, when decoloring, l-120 is generated due to the reaction between H+ and OH-, and H2O oxidizes the ITO transparent electrode and the 2-reflection layer that is the counter electrode.
An insulating film is formed on the surface of the electrode, increasing the elasticity of the electrode and significantly deteriorating the response of the element. This phenomenon occurs significantly when the driving voltage of the EC element is continuously applied, although it depends on the voltage value of the applied voltage.

The conventional driving method for an EC anti-glare mirror using an EC element is to apply a DC voltage of 1.35V, which is the maximum driving voltage, for a predetermined period of time when coloring, and then to maintain the coloring density, a coloring maintenance voltage of 1.35V is applied for a predetermined period of time. 2V (reflectance maintained at approximately 17%) was continuously applied. Further, when decoloring, an M current voltage of 0.5 to 1.35 V, which has the opposite polarity to the voltage applied during coloring, was continuously applied. When using anti-glare mirrors for automobiles, that is, EC anti-glare mirrors, comparing the time period when coloring reaches the specified color density, the time period when coloring is more decoloring than the time period when coloring density is maintained, and the time period when coloring and decoloring are maintained. Most of the damage occurs during this time period, and the continuous application of the drive voltage during this time period is considered to be a major factor in the deterioration.

Furthermore, depending on the usage conditions of the EC element anti-glare mirror for automobiles, it is sometimes necessary to repeatedly perform a series of reversal operations of the EC element from coloring to embellishing and from embellishing to tinting. In conventional drive circuits configured in such a way that the polarity of the applied voltage is reversed and applied when coloring and decoloring, a large rising current at the time of switching is repeatedly caused to flow through the power supply circuit each time due to this reversal of the applied voltage. For,
This may lead to heat generation and deterioration of the power supply transistor, so the parts used must have a large capacity, and a switching circuit for reversing the polarity of the applied voltage is also required, making the circuit complicated.

[Problems to be Solved by the Invention] As described above, in anti-glare mirrors for automobiles, the deterioration of the EC element and the heat generation deterioration of related elements, especially the power transistors of the power supply circuit and switching circuit, due to the frequent switching between coloring and decoloring. There were also problems in terms of circuit maintenance. An object of the present invention is to prevent deterioration of the EC element and related elements caused by these conventional driving methods, and to extend its life.

[Means for Solving the Problems] In order to achieve the above-mentioned object, in the present invention, the deterioration generation process is defined as a process from voltage application to coloring, a process of maintaining coloring after coloring, and a process of decoloring after decoloring. The object of the present invention is to provide a driving method that minimizes deterioration in each process.

That is, as for the driving method in the process from voltage application to coloring in the former case, it is necessary to consider responsiveness, and due to the linear nature of the EC element, the applied voltage is large at the beginning of application. Taking into account the drop in the current, a stepped rectangular wave voltage having a high voltage value was applied until the current applied almost approached the saturation value, and both terminals of the EC element were short-circuited when decoloring.

Next, as a driving method in the process of maintaining coloring after coloring, a pulse-like voltage having the same polarity as the coloring maintaining voltage and whose peak value is lower than the stepwise rectangular wave voltage at the end of coloring is used. An intermittent voltage was applied.

Further, as a drive circuit for carrying out the above driving method, a stepwise DC voltage supply circuit is used, and a stepwise DC voltage is applied to the EC element to color it, or the EC element is separated from the application circuit and the terminals of the EC element are short-circuited. , a switching circuit for decoloring, a coloring/decoloring switching signal circuit for outputting a stepped rectangular wave voltage for coloring, a pulsed intermittent voltage application signal for maintaining coloring, and a short circuit signal for decoloring, a control pulse circuit, and a pulse An EC anti-glare mirror drive circuit consisting of an oscillation circuit and a NOR circuit was prepared.

In addition, as a stepped DC voltage supply circuit, we prepared a series type voltage regulator circuit consisting of a monostable multivibrator, an operational amplifier that changes the reference voltage using the output of the monostable multivibrator, and a series transistor to define the output voltage.

[Function] When the driving method described above is used, the responsiveness of the element is improved during the coloring process by voltage application, and in the process of maintaining coloring after coloring, a pulsed intermittent voltage is used instead of the conventional continuous application. By applying , the deterioration of the element can be kept to a minimum by short-circuiting when decoloring, and the life of the EC element can be extended.

In addition, the conventional application of drive voltage during erasing was stopped and the terminals of the EC element were short-circuited for a certain period of time to erase the color, making it possible to prevent deterioration of the EC element due to the conventional application of drive voltage during erasing. Furthermore, there is no inrush current when switching colors, and it is possible to prevent deterioration of not only the EC element but also related elements such as power transistors due to overheating.

As mentioned above, the drive circuit includes a main circuit consisting of a stabilized power supply circuit, a stepped DC voltage supply circuit, a switching circuit, an E'C element, a coloring/decoloring trigger pulse circuit, a control pulse circuit, and a coloring/decoloring switching signal circuit. and an auxiliary circuit consisting of a stepwise rectangular wave voltage application signal circuit for coloring and a short-circuit signal circuit for decoloring;
The auxiliary circuit for maintaining coloring consists of a pulse oscillation circuit, a NOR circuit, and a signal circuit for applying a pulsed intermittent voltage for maintaining coloring.Especially when decoloring, the EC element is short-circuited. There is also no inrush current when switching colors, it is possible to prevent deterioration of the power supply circuit elements and to simplify the switching circuit, and it is possible to provide a drive circuit that operates reliably.

Further, the stepwise DC voltage supply circuit can supply a DC voltage that has been waveform-shaped in advance, and the circuit configuration can be simplified compared to the case using conventional means.

[Example] FIG. 1 is a driving applied voltage waveform diagram showing an example of the method for driving an EC anti-glare mirror according to the present invention. In Figure 1,
T1 refers to the coloring period, which is the time from when the voltage applied at the time of incoming call starts to be applied to the EC element until the time when the EC element is short-circuited at the time of the next color erasure.

tCI refers to the time it takes for coloring to progress to a certain extent by applying a voltage value with a high peak value of a stepped rectangular wave voltage, and for the energizing current to decrease until it almost reaches the saturation value, and after tC+ has elapsed, the applied voltage is reduced to V. Lower it to VS. TC refers to the coloring process from when the EC element is colored by the application of voltage at the time of incoming call until it reaches the fixed color density. ■, refers to the coloring maintenance process until the EC element reaches a predetermined color density and the EC element is short-circuited during the next erasing; T2 is the coloring process until the EC element is short-circuited at the time of erasing, and the color is erased. shows.

In FIG. 1, in the coloring process Tc, the applied voltage is j
After c+, a stepwise rectangular wave voltage 1 is applied which is lowered to V and then Vs, and the voltage V is high at the beginning of application. is applied, and when the coloring process has progressed, the applied voltage J is lowered to Vs, and the predetermined color density is reached at TC.

Next, after reaching the predetermined fixed color density as described above, the peak value Vs,
T is a coloring maintenance process of a pulsed intermittent voltage 2 having a pulse width TD2 and a pulse interval TO+. Apply for a period of time.

Then, in the embellishing process, both terminals of the EC element are short-circuited across T.

In addition, the settings are tc+=5sec tc? =5sec Tc=jc+ +tc2=10sec C-T2 1 sec≦tD+≦2osec.

10<tD+/tD2<20yD=
1.35V VS=1.2V seems appropriate.

FIG. 2 is a block diagram of a drive circuit that implements the EC anti-glare mirror drive method of the present invention.

As shown in the figure, the drive circuit of the present invention includes a stabilized power supply circuit 1
0, stepwise DC voltage supply circuit 11, coloring/decoloring trigger gas pulse circuit 20. Control pulse circuit 21, coloring/decoloring switching signal circuit 22, coloring step rectangular wave voltage application signal circuit 23, color erasing short circuit signal circuit 24, pulse oscillation circuit 25, NOR circuit 26, pulsed intermittent voltage application signal circuit 27, a switching circuit 28, and an EC element 29.

As shown in the figure, the drive circuit of the present invention includes a stabilized power supply circuit 10.
, a stepped DC voltage supply circuit 11 and a switching circuit 28
a main circuit consisting of an EC element 29, a coloring/decoloring trigger pulse circuit 20, a control pulse circuit 21, and a coloring/decoloring switching signal circuit 2.
2, an auxiliary circuit consisting of a stepwise rectangular wave voltage application signal circuit 23 for coloring, and a decoloring short-circuit signal q circuit 24, and a pulse oscillation circuit 2.
5, a NOR circuit 26, and an i-th circuit 27 for applying a pulsed intermittent voltage for maintaining coloring.

The stepped DC voltage supply circuit 11 uses the monostable multivibrator 4 to increase the reference voltage of the series type constant voltage circuit using the operational amplifier 3 for a predetermined time (tC+), and produces a high voltage V only during tC+. After tC1 has elapsed, a stepped DC voltage having a voltage waveform of a low voltage Vs is generated by activating the monostable multivibrator 4 using a coloring/decoloring trigger pulse, and is supplied to the switching circuit 28.

The control pulse circuit 21 is composed of a monostable multivibrator 5, and outputs a pulse of TC=72 (Tc=72 in this embodiment) according to the trigger pulse from the coloring/decoloring 1-rega pulse circuit 20 to apply the coloring process. Establish time and short circuit time when decoloring.

The coloring/decoloring switching signal circuit 22 is composed of an R-8-D-FF6, and outputs a coloring or decoloring signal each time a pulse is inputted by a trigger pulse from the coloring/decoloring trigger pulse circuit 20.

The pulse oscillation circuit 25 is composed of an astable multivibrator using an operational amplifier 7.

The switching circuit 28 is E when colored by the transistor.
This is a switching circuit for applying a drive voltage to a C element and shorting and opening both terminals of an EC element during color erasure.

The operation of the drive circuit of the present invention will be explained below.

When the coloring/decoloring trigger pulse is output from the coloring/decoloring trigger pulse circuit, the trigger pulse is supplied to the stepped DC voltage supply circuit 1.
1. Simultaneously input to the control pulse circuit 21 and the coloring/decoloring switching signal circuit 22, and the stepped DC voltage supply circuit 11 generates tCl.
A DC voltage switching circuit with only a high voltage V, 28
supply to

At the time of coloring, the control pulse circuit 21 outputs a pulse with a pulse width TC (TC=T2) in response to the trigger pulses inputted simultaneously, and the coloring signal circuit 22 outputs a coloring signal simultaneously outputted in response to the trigger pulses. It is selected in the coloring staged rectangular wave voltage application signal circuit 23 and outputs the coloring staged rectangular wave voltage application signal to the switching circuit 28 . Further, the NOR circuit 26 combines the pulses output from the oscillation circuit 25 and the pulses output from the Ruri control pulse circuit 21, and applies the applied voltage during the coloring maintenance process to simulate the completion of the coloring process via the pulsed intermittent voltage application signal circuit 27. An application signal of a certain pulsed intermittent voltage is output to the switching circuit 28.

When decoloring, from the coloring/decoloring trigger pulse circuit 20,
When a trigger pulse is output, the trigger pulse causes the control pulse circuit 21 to output a control pulse, and the coloring/decoloring switching signal circuit 22 outputs an embellishing signal, which is selected by the decoloring short-circuit signal circuit 24 and short-circuited. The signal is output to the switching circuit 28.

In this manner, the drive circuit 28 performs a switching action using the built-in transistor, and colors and decolors the EC element.

The transistor circuit built into the switching circuit 28 opens the EC element from the circuit when there is no signal applied to the base of the transistor, and opens the EC element when no voltage is applied in the coloring maintenance state or coloring state. The configuration is as follows.

Note that FIG. 3 shows a physical circuit configuration of the drive circuit shown in the block diagram of FIG. 2.

11 is a stepped DC voltage supply circuit, 20 is a coloring/decoloring trigger pulse circuit, 21 is a control pulse circuit, 22 is a coloring/decoloring switching signal circuit, 23 is a coloring step rectangular wave voltage application signal circuit,
24 is a decoloring short circuit signal circuit, 25 is a pulse oscillation circuit, 2
6 is a NOR circuit, 27 is a pulsed intermittent voltage application signal circuit, 28 is a switching circuit, and 29 is an EC element.

[Effects of the Invention] The method for driving an EC anti-glare mirror according to the present invention prepares a stepped rectangular wave voltage and a pulsed intermittent voltage with a high voltage at the beginning of application, and controls the coloring process (from voltage application to a predetermined color density). For coloring), only Tc of the former stepped rectangular wave voltage was applied, and for the subsequent coloring maintenance process, a pulsed intermittent voltage having the same polarity as the former was applied. Also, when decoloring, use EC.
Both terminals of the element were short-circuited to erase the color, and then opened.

Since the configuration is such that the driving voltage as described above is applied, the responsiveness of the element is improved in the process from voltage application to coloring and decoloring, and deterioration caused by continuous application in the coloring maintenance process and the decoloring process can be eliminated. We were able to provide a driving method that can also extend the life of the element.

In addition, as mentioned above, the drive circuit stopped applying the dynamic voltage during dljl special color, and the color was erased by short-circuiting the terminals of the EC element for a certain period of time, so there was no inrush current when changing the color, and the power transistor, etc. This not only prevents the elements from deteriorating due to overheating, but also simplifies the switching circuit.

In addition, the main circuit, control circuit, and coloring maintenance auxiliary circuit are divided into simple structures, making it possible to provide a drive circuit that operates reliably.

[Brief explanation of the drawing]

FIG. 1 is a drive applied voltage waveform diagram according to an embodiment of the present invention, FIG. 2 is a block diagram of a drive circuit implementing the EC anti-glare mirror driving method of the present invention, and FIG. 3 is a block diagram of the drive circuit shown in FIG. It is a drive circuit diagram specifically shown. DESCRIPTION OF SYMBOLS 1... Stepped rectangular wave voltage for coloring, 2... Pulsed intermittent voltage for maintaining coloring, 3... Operational amplifier, 4.5... Monostable multivibrator, 6... R-8-D- FF. 7... operational amplifier, 10... stabilized power supply circuit, 11
... Stepped DC voltage supply circuit, 20 ... Coloring and decoloring trigger pulse circuit, 21 ... Control pulse circuit, 22 ...
@ Color switching signal circuit, 23... Signal circuit for applying stepwise rectangular wave voltage for coloring, 24... Short-circuit signal circuit for decoloring, 25
...Pulse oscillation circuit, 26...NOR circuit, 27.
... Applied signal circuit for pulsed intermittent voltage, 28... Switching circuit, 29... EC element.

Claims (1)

[Claims] 1. In a method for driving an anti-glare mirror using an electrochromic element, a stepwise rectangular wave voltage having a high voltage value at the beginning of application and a pulse-like voltage having a voltage peak value of the same polarity as the voltage are applied. An EC anti-glare mirror driving method characterized in that an intermittent voltage is prepared as a coloring drive applied voltage, and when decoloring, both terminals of an electrochromic element are short-circuited. 2. A stepped DC voltage supply circuit, a switching circuit that applies a stepped DC voltage to the electrochromic element to color it, or separates the electrochromic element from the circuit and short-circuits both terminals to decolorize it, and a switching circuit for coloring. An EC anti-glare mirror drive consisting of a coloring/decoloring switching signal circuit, a control pulse circuit, a pulse oscillation circuit, and a NOR circuit that outputs applied signals of a stepped rectangular wave voltage and a pulsed intermittent voltage for maintaining coloring, and a short circuit signal for decoloring. circuit. 3. Claim 2 provides that the stepped DC voltage supply circuit includes a series type voltage regulating circuit consisting of a monostable multivibrator, an operational amplifier that changes the reference voltage by the output of the monostable multivibrator, and a series transistor, and a series transistor. EC anti-glare mirror drive circuit.