JPH11295768A - Optical device and driving method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To keep a light transmittance constant even in an electro-chemical light-control element with less memory, or to make it variable in plural steps, and also to eliminate most of remaining erasure remainder and unevenness of coloring. SOLUTION: An optical device, wherein a light transmission quantity is adjustable by applying a voltage across working electrodes 21a, 21b and counter electrodes 30a, 30b, is provided with a pair of mutually opposed transparent electrodes 21a, 21b as working electrodes or counter electrodes. And, the device is arranged so that a pair of the transparent electrodes 21a, 21b can alternately be colored or discolored by controlling the voltage to be applied.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical device (for example, a display device for displaying numbers or characters, an XY matrix display, etc.) and a visible light region (wavelength: 400
フ ィ ル タ 700 nm), and a driving method thereof.

[0002]

2. Description of the Related Art Conventionally, electrochromic materials (EC
The material is used in a voltage-driven display device, for example, a digital clock that displays time.

[0003] Electrochromic display device (ECD)
Is a non-light emitting type display device, which has an advantage that the display is based on reflected light or transmitted light, so that there is little fatigue even after long-time observation, and the driving voltage is relatively low and the power consumption is low. Has few advantages. For example,
As disclosed in JP-A-59-24879, a liquid-type ECD using an organic molecular viologen molecule derivative which forms a reversibly colored and decolored state as an EC material is known.

[0004] With the development of precision optical instruments, a fine and low power consumption type light quantity adjusting device which replaces the conventional variable ND filter is required.
In addition to the CD or its peripheral technology, a transmission type or reflection type electrochemical dimming device utilizing the precipitation / dissolution of a metal salt such as silver halide has been developed.

FIGS. 4 to 7 show an example of a conventional dimming element, where 1 is a transparent electrode, 2 and 12 are lead wires,
3 is an insulating film, 4 and 14 are external contacts (terminals), 5 is a substrate,
6 and 8 are openings, and 10 is a counter electrode. Note that the scale in the thickness direction of the film in the drawing is different from the scale in the XY direction (in-plane direction of the paper surface). : Several thousand Å, lead wires 2 and 12: several thousand Å, insulating film 3: several μm, which is extremely thin and cannot be expressed in actual magnification (hereinafter, the thickness of the film in FIG. Notation shall follow this).

This dimming element uses two substrates 1 as described above, sandwiches a spacer between them, and places a liquid (for example, an organic molecular viologen derivative or the like) in the space between them.
And applying a potential to change the light transmittance.

More specifically, in FIGS. 6 and 7, 5a and 5
b is a substrate having the above configuration, 6a and 6b, 8a and 8b are openings, 1a and 1b are transparent electrodes similar to the above, 3a and 3
b is an insulating film similar to the above, 7 is a spacer, 9 is a liquid whose light transmittance is adjustable, 10a and 10b are counter electrodes, 11
Is a sealing adhesive.

Then, the transparent electrodes (working electrodes) 1a and 1
7, the deposit 22 is deposited from the liquid 9 on the transparent electrodes 1a and 1b from the liquid 9 as shown by arrows, depending on the polarity of the voltage applied between the electrode b and the return electrode plates 10a and 10b. Then, the deposit 22 is dissociated and moved onto the counter electrodes 10a and 10b, so that a light transmitting state (decoloring state) is obtained.

[0009]

However, in the dimming device described above, the following problems have occurred when the light transmittance is kept constant.

(1) An electrochemical dimming element typified by electrochromic has a finite memory property, and the transmittance changes after a certain period of time in the state shown in FIG. Therefore, periodic charge injection is required to maintain the transmittance for a long time.

(2) In this electrochromic device, the insulating films 3a and 3b and the transparent electrodes 1a and 1b
The current density concentrates near the boundary between the two and causes uneven coloring. For this reason, the density near the boundary is high, and the density near the center tends to be low. If the charge is periodically injected as in the above (1) in the state where the coloring unevenness exists, the coloring unevenness is accumulated more and more, and it is difficult to erase the color. This remains unremoved, which shortens the life of the element itself, causes visual defects in the display element, and deteriorates optical characteristics such as film loss (local light transmission state due to uneven deposition). .

(3) If one surface of the transparent electrode is colored at a high concentration (in a state where light is hardly transmitted) and the color is repeatedly erased, a disappearance remains near the boundary between the insulating film and the transparent electrode.

An object of the present invention is to provide a light control device which can maintain a constant light transmittance or change the light transmittance in a plurality of steps even in an electrochemical light control device having a small memory property, and has almost no disappearance or uneven coloring. An object of the present invention is to provide an optical device and a driving method thereof.

[0014]

That is, the present invention provides an optical device in which the amount of light transmission can be adjusted by applying a voltage between a working electrode and a counter electrode. An optical device (hereinafter, referred to as an optical device of the present invention) having the counter electrode, wherein the pair of transparent electrodes are alternately colored or decolored by controlling the voltage application. Things.

The present invention also relates to a method of driving an optical device in which the amount of light transmission can be adjusted by applying a voltage between a working electrode and a counter electrode, wherein a pair of transparent electrodes opposed to each other are used as the working electrode or the counter electrode. A method of driving the optical device, wherein the pair of transparent electrodes are alternately colored or decolored by controlling the voltage application, and the light transmission amount is kept constant or changed in a plurality of steps. This is also referred to as a driving method of the invention.

In the optical device and the method of driving the same according to the present invention, the above-mentioned "transparent electrode" means an electrode capable of transmitting applied light (incident light), and is optically transparent or translucent. It may be.

According to the optical device and the driving method of the present invention, the pair of transparent electrodes facing each other are alternately colored or decolored by controlling the voltage, so that the light transmittance is equal to the state of each of the pair of transparent electrodes. Thus, the light transmittance can be kept constant or can be changed in a plurality of steps even in an electrochemical light control device having a small memory property.

In the drive for keeping the light transmittance constant, charge injection is not necessary as in the prior art, so that no disappearance remains due to the accumulation of coloring unevenness. In this case, since the transparent electrodes face each other, the current density of each transparent electrode is relatively reduced, and the concentration of the current density near the boundary between the transparent electrode and the insulating film can be relaxed. Almost no unevenness occurs. When a pair of transparent electrodes facing each other are colored or decolored at the same time, the density per one surface can be reduced, so that the occurrence of unremoved portions and the occurrence of uneven color density can be further reduced.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the optical device and the driving method of the present invention, a space is provided between the substrates having the transparent electrodes by using a spacer member, and the light transmission amount can be reversibly adjusted in this space. A light control element filled with a light transmission amount adjusting liquid or a solid, wherein the pair of transparent electrodes are alternately colored or decolored to maintain a constant light transmission amount or to change the light transmission amount in a plurality of steps. It is good to be constituted as follows.

Further, one of the pair of transparent electrodes facing each other (hereinafter, referred to as a transparent electrode X) is colored to reduce the transmittance, and a constant transmittance is maintained for a predetermined time, while the other (hereinafter, the transparent electrode X) is maintained. Y is maintained in a transparent state,
After a predetermined time, the colored transparent electrode X is used as a counter electrode, and a bias is applied from the transparent electrode X toward the transparent electrode Y with the transparent electrode Y maintaining a transparent state as a working electrode. , The transparent electrode X is driven to decolor, the transparent electrode Y is driven to be colored,
The total transmittance can be kept constant.

Further, one of the pair of transparent electrodes facing each other (hereinafter, referred to as a transparent electrode X) is colored to reduce the transmittance, and while maintaining a constant transmittance for a predetermined time, simultaneously with the other (hereinafter, the transparent electrode X). Y) keeps the transparent state,
After a lapse of a predetermined time, the colored transparent electrode X is decolorized, and at the same time, the transparent electrode Y that is in a transparent state is driven to be colored, so that the total transmittance can be kept constant.

Next, a preferred embodiment of the optical device of the present invention and its driving method will be described.

FIGS. 1 to 3 show the configuration of a light control element as an optical device according to the present embodiment. Here, 25a and 2
5b is a substrate, 21a and 21b are transparent electrodes used for dimming (lead wires are not shown, but are the same as those in FIGS. 4 and 5), 23a and 23b are insulating films, 30a and 30b
Is the opposite pole.

In this dimming device, the common substrate 25
The transparent electrodes 21a and 21b are formed on the a and 25b in a predetermined pattern together with the lead wires and the external contacts. Each of these films is formed by sputtering, vapor deposition or CVD (Chemic) generally used for forming a thin film.
al Vapor Deposition) method.

The material of the lead wire is Cr / Au / C
r or Cr / Cu / Cr may be used. As a material of the transparent electrode, indium-tin oxide (IT
O), indium oxide (In ₂ O ₃ ), SnO ₂ or Z
nO can be used. The external contact is integral with the lead wire and is not separately formed and patterned, but is merely classified as a function. The thickness of each transparent electrode and lead wire is several thousand Å, and the thickness of the insulating film is several μm.

Then, counter electrodes 30a and 30b are formed on the sides of the transparent electrodes 21a and 21b so as to have predetermined positions and shapes. On the counter electrode, a coating film of conductive resin material (filler is silver powder etc.), plating film or sputtering,
There is a film formation by a chemical or physical film formation method such as a CVD method, or an Ag plate.

In the above-mentioned light control device, as shown in FIGS. 4 and 5, the periphery of the transparent electrodes 21a and 21b is
3a and 23b, a terminal of a low-resistance electrode material is led out under the insulating layer, and a pair of substrates 25a and 25b is bonded on the insulating layers 23a and 23b with an adhesive 41 via a spacer 27. ing. Accordingly, since the portion where the substrates 25a and 25b and the spacer 27 are bonded is flat, there is no gap at this bonded portion.
There is no leakage of the enclosed liquid 29 whose light transmittance can be adjusted (for example, an organic molecular viologen derivative).

Next, an example of a method of driving the light control device according to the present embodiment will be described.

Driving Method 1 for Light Control Element (FIG. 1) The light control element shown in FIG. 1 is driven as follows to maintain a constant transmittance of light passing through the light control element, Alternatively, it can be changed in multiple stages. However, the time (memory property) for maintaining the transmittance of the material used for the light control element that is acceptable as a specification is measured in advance, or the light control is performed by using a light transmittance sensor such as a light emitting diode and a detector. The transmittance of the optical element is constantly monitored.

A current of 50 A flows from the counter electrode 30b to the transparent electrode 21a, and the surface of the transparent electrode 21a is colored with the deposit 42A. When a certain transmittance is reached, the flow of current is stopped. It is kept in a certain predetermined transmittance. After a lapse of time during which the memory property can be maintained (or when the sensor detects that the transmittance has changed to a certain value), the current 5 is applied from the transparent electrode 21a to the transparent electrode 21b.
0B, the transparent electrode 21a is decolorized, and the transparent electrode 21b
Is colored with the deposit 42B. Same as above. By driving in the opposite manner to the above, a current 50C is applied from the transparent electrode 21b to the transparent electrode 21a, and the transparent electrode 21a
Is colored with the deposit 42C to decolor the transparent electrode 21b. Repeat the above ~.

By driving in this manner, the transparent electrode can be completely erased once and then colored, so that there is no accumulation of coloring unevenness as described in the problem of the prior art. In other words, no remaining disappearance occurs. Moreover, the transmittance can be kept by the other transparent electrode, and by driving as described above, the total transmittance of the light control element does not always change even when the charge is moving.

In this way, even in a light control device made of a material having poor memory properties, the light control device can be used without adversely affecting the optical characteristics.
Effectively, the transmittance can be kept constant.

Driving method 2 of the dimming element (FIG. 2) Driving method 2 which produces the same effect as the above-mentioned driving method 1 will be described. In FIG. Can be kept constant or can be changed in multiple steps. However, the time required for maintaining the transmittance of the material used for the dimming element, which is acceptable as a specification (memory property), is measured in advance, or the dimming is performed using a transmittance sensor such as a light emitting diode and a detector. The transmittance of the optical element is constantly monitored.

A current of 60 A flows from the counter electrode 30a to the transparent electrode 21a, and the surface of the transparent electrode 21a is colored with the deposit 52A. When a certain transmittance is reached, the flow of current is stopped. It is kept in a certain predetermined transmittance. After a lapse of time during which the memory property can be maintained (or when a sensor detects that the transmittance has changed to a certain value), a current 60B flows from the transparent electrode 21a to the counter electrode 30a.
To erase the color of the transparent electrode 21a. At the same time, a current 60C is applied from the counter electrode 30b to the transparent electrode 21b to color the transparent electrode 21b with the deposit 52B. Same as above. By driving in the opposite direction to the above, currents 60D and 60A are passed to erase the color of the transparent electrode 21b, and at the same time,
1a is colored with the deposit 52A. Repeat the above ~.

In the above case, the transmittance is changed in multiple stages as described below, or the total transmittance is controlled to be constant. Here, the movement of the two transparent electrodes when keeping the transmittance of 5% in total is shown below as an example (Example 1). However, the allowable range of the transmittance to be kept is determined by the specification of each device, and thus does not matter here.

[0036]

An example of a movement in which the transmittance is changed in multiple stages using this control method is shown below (Example 2). Maintain (keep) the transmittance or change the transmittance (5% →
In some cases, such as 20% to 50%), the total transmittance is prevented from suddenly changing.

<Example 2> Transparent electrode 21a Transmittance of transmittance of transparent electrode 21b Total transmittance of two surfaces 5% 100% 5% 5% hold → 100% 5% 5% Transition to 20% → 20% × 100 % = 20% 20% hold → 100% 20% 20% Transition to 50% → 50% 100% 50%

When driven in this manner, the transparent electrode can be completely decolored once and then colored, as in Driving Method 1. Therefore, there is no accumulation of coloring unevenness as described in the problem of the prior art. In other words, no disappearance occurs. Moreover, the transmittance is kept by the other transparent electrode, and
In such a case, by driving as in Example 1, the transmittance of the light control element can be kept unchanged even when the charge is moving.

In this way, even in a light control device made of a material having poor memory properties, the light control device can be used without adversely affecting the optical characteristics.
It is possible to effectively maintain the transmittance constant or control the transmittance in multiple stages.

Driving Method 3 (Reference Example) (FIG. 3) In driving an electrochromic device as shown in FIG. 3, insulating films 23a and 23b and transparent electrode 21
As described above, the current density concentrates near the boundary between a and 21b, causing uneven coloring, but this greatly changes depending on the coloring density. In other words, the deeper the color, the greater the difference in density between the vicinity of the boundary and the center. And, the deeper the color, the more likely it is for the remaining color to disappear when the color is erased.

At this time, the two transparent electrodes 21a and the transparent electrode 21b facing the element are simultaneously driven. That is, when currents 70A and 70B are passed from the counter electrodes 30a and 30b to the transparent electrode 21a and the transparent electrode 21b, the concentration of the deposits 62A and 62B per sheet does not need to be so high, so that the remaining disappearance is suppressed. be able to.

At this time, the total transmittance of the two surfaces is set to, for example, 5
%, The following shows about five examples of how to set the transmittance of each transparent electrode. Of course, there are more combinations.

Transparent electrode 21 a Transmittance of transmittance of transparent electrode 21 b Total transmittance of two surfaces 5% 100% 20% 25% 50% × 10% = 5% (constant) 80% 6.25% 100% 5%

However, an element having almost infinite memory properties,
Alternatively, it is effective only when the device satisfies the specifications as a device. If not, the transmittance cannot be kept constant without remaining disappearance, and remaining disappearance occurs. When the power is off, be sure to erase all the transparent electrodes and make them transparent.

As is clear from the above description,
The light control device according to the present invention has the following remarkable advantages.

(A) Even in an electrochemical dimming device having a small memory property, the light transmittance can be changed in multiple steps or kept constant by using the driving method of the present invention. (B) In the drive for keeping the light transmittance constant,
There is no disappearance due to the accumulation of the coloring unevenness. (C) Since the transparent electrodes are opposed to each other, the transmittance can be secured even if the current density of each electrode is relatively reduced,
There is almost no coloring unevenness due to current concentration.

In the above example, the transparent electrodes 21a and 21b used for dimming and the counter electrodes 30a and 30b are used one by one, but three transparent electrodes are used for dimming.
Surfaces, five transparent electrodes for conducting with the conductive film, etc.
Many combinations are conceivable and can be changed according to the purpose and specifications.

The materials, shapes, structures, etc. of the constituent parts of the element, including each film, may be variously changed. The liquid whose light transmittance can be adjusted is not limited to the viologen molecule derivative, but may be Ag.
Silver halide such as Br can be used.

The optical device according to the present invention can be combined with various known filter materials (for example, organic electrochromic materials, liquid crystals, and electroluminescent materials). Further, the optical device according to the present invention has a C
It can be widely applied to various optical systems such as an optical diaphragm of a CD, and also to a light amount adjustment of an electrophotographic copying machine or an optical communication device.

[0051]

According to the optical apparatus and the driving method of the present invention, the pair of transparent electrodes facing each other are alternately colored or decolored by controlling the voltage, so that the light transmittance is equal to that of the pair of transparent electrodes. As a result, the light transmittance can be kept constant or can be changed in a plurality of stages even in an electrochemical light control device having a small memory property.

In the drive for maintaining the light transmittance constant, charge injection is not required as in the related art, so that no disappearance remains due to the accumulation of coloring unevenness. In this case, since the transparent electrodes face each other, the current density of each transparent electrode is relatively reduced, and the concentration of the current density near the boundary between the transparent electrode and the insulating film can be relaxed. Almost no unevenness occurs.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a driving method 1 of an optical device according to the present invention.

FIG. 2 is a cross-sectional view showing a driving method 2 of the optical device according to the present invention.

FIG. 3 is a sectional view showing a driving method 3 of the optical device based on the reference example.

FIG. 4 is a plan view of a substrate of an optical device according to a conventional example.

FIG. 5 is a sectional view taken along line VV of FIG. 4;

6 is a cross-sectional view of the device taken along the line VI-VI of FIG.

FIG. 7 is a cross-sectional view similar to FIG. 6, showing a situation during operation.

[Explanation of symbols]

1, 1a, 1b, 21a, 21b ... transparent electrode, 2, 2
a, 2b ... lead wire, 3, 3a, 3b, 23a, 23b
... insulating film, 5, 5a, 5b, 25a, 25b ... substrate,
7, 27: spacer, 9, 29: liquid with adjustable light transmittance, 30a, 30b: counter electrode, 41: adhesive, 42A, 4
2B, 42C, 52A, 52B, 62A, 62B ... deposits, 50A, 50B, 50C, 60A, 60B, 60
C, 60D, 70A, 70B ... current

Claims (6)

[Claims] 1. An optical device in which the amount of light transmission can be adjusted by applying a voltage between a working electrode and a counter electrode, comprising a pair of transparent electrodes facing each other as the working electrode or the counter electrode, and An optical device, wherein the pair of transparent electrodes are alternately colored or decolored by control. 2. A light control in which a space is provided between substrates having transparent electrodes using a spacer member, and this space is filled with a light transmission amount adjusting liquid or a solid capable of reversibly adjusting the light transmission amount. 2. The optical device according to claim 1, wherein the optical device is an element, wherein the pair of transparent electrodes are alternately colored or decolored to maintain a constant light transmission amount or change the light transmission amount in a plurality of steps. 3. A method of driving an optical device in which the amount of light transmission can be adjusted by applying a voltage between a working electrode and a counter electrode, wherein a pair of transparent electrodes facing each other are used as the working electrode or the counter electrode, and the voltage application is performed. The method of driving an optical device, wherein the pair of transparent electrodes are alternately colored or decolored by the control of (i), and the light transmission amount is kept constant or changed in a plurality of stages. 4. A light control in which a space is provided between a substrate having a transparent electrode using a spacer member, and this space is filled with a light transmission amount adjusting liquid or a solid capable of reversibly adjusting the light transmission amount. The method for driving an optical device according to claim 3, wherein the element is driven. 5. One of a pair of transparent electrodes facing each other (hereinafter, referred to as a transparent electrode X) is colored to reduce the transmittance, while maintaining a constant transmittance for a predetermined time, and at the same time as the other (hereinafter, a transparent electrode X). Y is maintained in a transparent state,
After a predetermined time, the colored transparent electrode X is used as a counter electrode, and a bias is applied from the transparent electrode X toward the transparent electrode Y with the transparent electrode Y maintaining a transparent state as a working electrode. , The transparent electrode X is driven to decolor, the transparent electrode Y is driven to be colored,
4. The method according to claim 3, wherein the total transmittance is kept constant. 6. A method of coloring one of a pair of transparent electrodes facing each other (hereinafter, referred to as a transparent electrode X) to reduce the transmittance, maintaining a constant transmittance for a predetermined time, and simultaneously performing the other (hereinafter, a transparent electrode X). Y) keeps the transparent state,
4. After a predetermined time has elapsed, the colored transparent electrode X is decolorized, and at the same time, the transparent electrode Y which is in a transparent state is driven so as to be colored, so that the total transmittance is kept constant. 3. The method for driving an optical device according to 1.