JP6496515B2 - Optical apparatus and optical element driving method - Google Patents

Description

  The present invention relates to an optical device including an electrodeposition element and a method for driving the electrodeposition element.

  Patent Document 1 discloses a so-called electrodeposition element. The electrodeposition element mainly has a pair of electrodes arranged opposite to each other and an electrolyte layer sandwiched between the pair of electrodes and containing an electrodeposition material containing silver.

  At regular times (when no voltage is applied), the electrolyte layer is almost transparent, and the electrodeposition element is in a transparent state. When a voltage is applied between the pair of electrodes, the electrodeposition material (silver) of the electrolyte layer is deposited and deposited on the electrodes by an oxidation / reduction reaction. Thereby, an electrodeposition element will be in a mirror surface (high light reflection) state.

  Patent Document 2 discloses a specific driving method (voltage applying method) in a simple matrix display device using an electrodeposition element. It is described that unevenness of an image displayed on the display device can be reduced by such a driving method.

JP 2012-181389 A JP 2003-337351 A

  A main object of the present invention is to accurately deposit and deposit an electrodeposition material at a desired position or region in an electrodeposition element.

According to a main aspect of the present invention, there are first and second substrates disposed opposite to each other, and the first substrate includes a first electrode provided on a surface close to the second substrate. The second substrate includes a second electrode provided on a surface close to the first substrate, and is sandwiched between the first and second substrates and the first and second substrates; An electrolyte layer containing an electrodeposition material containing silver, and a power source that is connected to the first and second electrodes and can apply a voltage to the electrolyte layer via the first and second electrodes The power supply periodically outputs a first step voltage in a first period, and the first step voltage holds a first voltage that is a positive voltage for a first time. Subsequently, a second voltage that is a positive voltage and smaller than the first voltage is set to a second time longer than the first time. Has a waveform held by said first voltage is not less than 3V, the first times are less than 5ms, the second voltage is in the range of 0.4V～1.0V, the first An optical device is provided wherein the second time is in the range of 50 ms to 300 ms .

According to another aspect of the present invention, there are first and second substrates disposed opposite to each other, the first substrate including a first electrode provided on a surface close to the second substrate. The second substrate includes a second electrode provided on a surface close to the first substrate, and is sandwiched between the first and second substrates and the first and second substrates; And an electrolyte layer containing an electrodeposition material containing silver, wherein the first step voltage is periodically applied to the electrolyte layer via the first and second electrodes. Including a step of applying, wherein the first step voltage holds the first voltage, which is a positive voltage, for a first time, and subsequently is a second voltage that is a positive voltage and is smaller than the first voltage. the has a waveform which holds a long second time than the first time, through the first and second electrodes When a DC voltage is applied to the electrolyte layer to deposit the electrodeposition material on the surface of the first or second electrode, the DC voltage at which the electrodeposition material starts to deposit is called a threshold voltage. There is provided a method of driving an optical element , wherein the first voltage is twice or more the threshold voltage, and the second voltage is lower than the threshold voltage .

  In the electrodeposition element, the electrodeposition material can be accurately deposited and deposited at a desired position or region.

and, FIG. 1A is a cross-sectional view showing the basic structure of an optical device including an electrodeposition element, and FIGS. 1B and 1C are graphs showing the wavelength dependence of light transmittance and light reflectance in the electrodeposition element. 1D is a schematic graph showing the applied voltage dependence of the light reflectance in the electrodeposition element, and FIG. 1E is a schematic graph showing the time change of the light reflectance in the electrodeposition element. . FIG. 2 is a plan view showing the electrodeposition element partially enlarged. 3A to 3C are schematic graphs showing driving waveforms of the electrodeposition element. FIG. 4A is a cross-sectional view showing another structural example of an optical device including an electrodeposition element, and FIG. 4B is a plan view showing an electrode structure of the electrodeposition element.

  FIG. 1A is a cross-sectional view showing a basic structure of an optical device according to an embodiment. The optical apparatus mainly includes an electrodeposition (ED) element 101 and a power source 102 that supplies electric power to the ED element 101.

  The ED element 101 mainly includes lower and upper substrates 10 and 20 that face each other, and a seal frame member 40 and an electrolyte layer (electrolytic solution) 50 that are sandwiched between the lower and upper substrates 10 and 20. . The seal frame member 40 is provided in a closed shape along the peripheral edges of the lower and upper substrates 10 and 20 in the surface of the lower or upper substrate 10 and 20. The electrolyte layer 50 contains an electrodeposition (ED) material and fills a space 50 a defined by the lower and upper substrates 10, 20 and the seal frame member 40.

  Lower and upper electrodes 12 and 22 are provided on opposing surfaces of the lower and upper substrates 10 and 20, respectively. The lower and upper electrodes 12 and 22 have, for example, a simple matrix type electrode structure. The power source 102 is connected to the lower and upper electrodes 12 and 22, and applies various voltages to the electrolyte layer 50 via the lower and upper electrodes 12 and 22.

  With reference to FIG. 1A, a method of manufacturing an optical device (particularly, the ED element 101) according to the embodiment will be described.

  First, two transparent substrates having electrodes formed on the surface of the base substrate are prepared. If necessary, the electrode on the surface of the base substrate is patterned into a desired planar shape by an etching method, a laser ablation method, or the like.

  As the base substrate, a light-transmitting substrate is used, and a plate substrate such as blue glass or a film substrate made of polycarbonate or the like can be used. The electrode is made of a member having translucency and conductivity, such as indium tin oxide (ITO) and indium zinc oxide (IZO).

  Of the two transparent substrates prepared, one substrate is set as the lower substrate 10 and the other substrate is set as the upper substrate 20. The base substrate and the electrodes in the lower substrate 10 are referred to as a lower base substrate 11 and a lower electrode 12, respectively. In addition, the base substrate and the electrodes in the upper substrate 20 are referred to as an upper base substrate 21 and an upper electrode 22, respectively.

  As will be described later with reference to FIG. 4, a particle deposition layer in which ITO particles or the like are deposited may be provided on the surfaces of the lower or upper electrodes 12 and 22. A particle deposition layer can be formed by applying the ITO particle dispersion to the surface of the lower or upper electrodes 12 and 22 using a spin coating method or the like, and then baking.

  Next, the seal frame member 40 is formed on the lower or upper substrate 10, 20 (the surface of the lower or upper electrode 12, 22), for example, the lower substrate 10. The seal frame member 40 has, for example, a rectangular frame-like overall planar shape and is made of an ultraviolet curable resin. The seal frame member 40 may be made of a thermosetting resin.

Subsequently, a gap control agent having a particle size of several tens of μm to several hundreds of μm, for example, 500 μm is sprayed on the lower or upper substrate 10, 20 (surface of the lower or upper electrode 12, 22), for example, the upper substrate 20. . The density of the gap control agent is, for example, about 1 to 3 pieces / mm ² . A columnar protrusion may be formed instead of spraying the gap control agent. Further, the gap control agent may be dispersed on the substrate on which the seal frame member 40 is formed, that is, the lower substrate 10.

  Next, an electrolytic solution (electrolyte layer) 50 containing an electrodeposition (ED) material containing silver is dropped inside the seal frame member 40 of the lower substrate 10 (the surface of the lower electrode 12). And the upper side board | substrate 20 is bonded to the lower side board | substrate 10 which dripped the electrolyte solution 50 so that the lower side and the upper side electrodes 12 and 22 may oppose. Thereafter, the seal frame member 40 is cured by irradiating the seal frame member 40 with ultraviolet rays. Thereby, the ED element 101 is completed.

The electrolytic solution (electrolyte layer) 50 includes, for example, an ED material (AgNO ₃ or the like), an electrolyte (TBABr or the like), a mediator (CuCl ₂ or the like), an electrolyte purifier (LiBr or the like), a solvent (DMSO: dimethyl-sulfoxide, etc.) Etc. Further, a gelling polymer (PVB: polyvinyl-butyral or the like) may be added to form a gel (jelly). In the examples, DMSO as a solvent was added with 50 mM AgNO ₃ as an ED material, 250 mM LiBr as a supporting electrolyte, 10 mM CuCl ₂ as a mediator, and 10 wt% PVB as a gelling polymer. .

In addition to AgNO ₃ , for example, AgClO ₄ containing silver, AgBr, or the like can be used as the ED material. Here, the ED material refers to a material in which a part of the ED material is deposited / deposited or disappears on the surfaces of the lower or upper electrodes 12 and 22 due to an oxidation-reduction reaction or the like.

The supporting electrolyte is not limited as long as it promotes the redox reaction or the like of the ED material. For example, lithium salts (LiCl, LiBr, LiI, LiBF ₄ , LiClO ₄ etc.), potassium salts (KCl, KBr, KI etc.), sodium salts (NaCl, NaBr, NaI etc.) can be suitably used.

As the mediator, in addition to CuCl ₂ containing copper, for example, CuSO ₄ containing Cu or CuBr ₂ containing copper can be used. Here, the mediator refers to a material that is oxidized and reduced at an electrochemically lower energy than silver.

  A solvent will not be limited if it can hold | maintain ED material etc. stably. For example, polar solvents such as water and propylene carbonate, non-polar organic solvents, ionic liquids, ionic conductive polymers, polymer electrolytes, and the like can be used. Specifically, in addition to DMSO, propylene carbonate, N, N-dimethylformamide, tetrahydrofuran, acetonitrile, polyvinyl sulfate, polystyrene sulfonic acid, polyacrylic acid, and the like can be suitably used.

  The electrolytic solution can be dropped using a dispenser, an inkjet head, or the like. The lower and upper substrates 10 and 20 can be bonded in the air, in a vacuum, or in a nitrogen atmosphere.

  Finally, the power supply 102 is connected to the lower and upper electrodes 12 and 22. Thereby, an optical device including the ED element 101 and the power source 102 is completed.

  For example, when the potential of the lower electrode 12 is used as a reference, the power source 102 applies a positive DC potential (approximately 3 [V] for several tens of seconds) to the upper electrode 22 (that is, the potential of the upper electrode 22). , When a negative DC voltage is applied to the lower electrode 12), silver ions (ED material) in the electrolyte layer 50 are reduced on the surface of the lower substrate 10 (lower electrode 12), A silver thin film (ED material film) is deposited. When a negative DC potential is applied to the upper electrode 22 when the potential of the lower electrode 12 is used as a reference, a silver thin film is deposited on the surface of the upper substrate 20 (upper electrode 22).

  1B and 1C are graphs showing a light transmission spectrum and a light reflection spectrum of the ED element in a steady state (when no voltage is applied) or when a voltage is applied. 1B and 1C, the horizontal axis indicates the wavelength of light incident on the ED element, and the vertical axis indicates the transmittance and the reflectance with respect to the wavelength of the incident light, respectively.

  In FIG. 1B, spectrum Toff is the light transmission spectrum of the ED element at the steady state, and spectrum Ton is the light transmission spectrum of the ED element at the time of voltage application. Further, in FIG. 1C, spectrum Roff is a light reflection spectrum of the ED element in a steady state, and spectrum Ron is a light reflection spectrum when a voltage is applied.

As shown in the spectrum Toff of FIG. 1B, the electrolyte layer is generally transparent and the ED element achieves a transparent state at the steady state. In addition, the ED element in an Example looks a little yellowish. This is considered to be an influence of the mediator (CuCl ₂ ). Such slight coloring can be improved by reducing the thickness of the ED element (decreasing the distance between the lower and upper substrates). That is, by reducing the thickness of the ED element (decreasing the distance between the lower and upper substrates), the ED element can be made colorless and transparent (the light transmission spectrum can be made flat). Note that, as shown in the spectrum Roff of FIG. 1C, the light reflectance of the ED element is extremely low in a steady state.

  As shown in the spectrum Ron of FIG. 1C, since a silver thin film (high light reflection film) is deposited on the electrode surface when a voltage is applied, the ED element realizes a mirror surface state (high light reflection state). As shown in the spectrum Ton of FIG. 1B, the light transmittance of the ED element is extremely low when a voltage is applied.

  When the voltage application to the ED element is stopped, the silver (thin film) deposited on the electrode surface is dissolved again as silver ions in the electrolyte layer and disappears from the electrode surface. Thereby, the ED element realizes a transparent state again.

  FIG. 1D is a graph schematically showing a light reflectance characteristic of an ED element with respect to an applied voltage. The horizontal axis indicates the voltage value of the DC voltage applied to the ED element, and the vertical axis indicates the light reflectance at an arbitrary wavelength of the ED element. As shown in FIG. 1D, the light reflectivity of the ED element at the normal time (0 [V]) is low, and when the voltage applied to the ED element is increased, the light reflectivity is also increased. When a large voltage is applied for a long time, the light reflectance of the ED element is saturated.

  Here, the light reflectance of the ED element in a steady state is defined as R0, and the light reflectance of the ED element when a sufficiently high voltage is applied for a long time is defined as R1. When the light reflectance of the ED element is 90% of R1 (0.9 × R1), the light reflectance of the ED element is considered to be saturated, and the light reflectance of the ED element at this time is defined as Rs. To do.

  Further, a voltage value applied to the ED element when the light reflectance of the ED element is 90% of R1 (0.9 × R1 = Rs) is defined as a saturation voltage vs. The voltage applied to the ED element when the light reflectance of the ED element is 10% of R1 (0.1 × R1) is defined as a voltage (threshold voltage) vt at which the ED material (silver) starts to precipitate. Define.

  In the ED element of the embodiment, the saturation voltage vs is approximately 2.6 [V] to 3.0 [V], and the threshold voltage vt is approximately 1.2 [V] to 1.3 [V]. . It should be noted that parameters such as saturation voltage and threshold voltage vary depending on the ratio of various members constituting the electrolyte layer.

  FIG. 1E is a graph schematically showing a temporal change in light reflectance in the ED element when the saturation voltage vs is applied. The horizontal axis indicates the time during which the saturation voltage vs is applied to the ED element, and the vertical axis indicates the light reflectance at an arbitrary wavelength of the ED element. Note that the time point when the saturation voltage vs is applied to the ED element is defined as t0.

  As shown in FIG. 1E, when a saturation voltage vs is applied to the ED element, the light reflectance gradually increases, and when a sufficiently long time has elapsed, the light reflectance is saturated and becomes Rs. Here, a time from when the saturation voltage vs is applied to the ED element until the light reflectance of the ED element reaches 90% of Rs is defined as a response time tr.

  In the ED element of the embodiment, the response time tr is about 0.5 seconds to 2.0 seconds. It should be noted that parameters such as response time vary depending on the ratio of various members constituting the electrolyte layer.

  FIG. 2 is an enlarged plan view showing a part of the ED element. A simple matrix type electrode structure is assumed as the electrode structure of the lower and upper electrodes 12 and 22. That is, as the shapes of the lower and upper electrodes 12 and 22, the lower electrode 12 extending in one direction and the upper electrode 22 extending in a direction orthogonal thereto are assumed. For example, the widths of the lower and upper electrodes 12 and 22 are each about 5 mm.

  When a DC voltage is applied between the lower and upper electrodes 12, 22, the ED material (silver) contained in the electrolyte layer is deposited and deposited on the surface of the lower or upper substrate 10, 20, and as a result, the ED material film (Silver thin film) is formed. According to the study of the present inventors, at this time, the ED material film may be formed in a region 103E wider than the region 103 where the lower and upper electrodes 12, 22 overlap. It is desirable in terms of product design that the ED material film is formed in a predetermined desired region, that is, a region where electrodes overlap (electrode overlapping region).

  Further, if a DC voltage is continuously applied for a long time (for example, about 3 [V] for 10 seconds), the formed ED material film becomes too thick and may be partially peeled off. It is desirable in terms of product quality that the ED material film is formed with a uniform thickness, that is, it maintains a uniform light reflectivity for a long time.

  The present inventor has studied a driving method of an ED element in which an ED material film is formed in a desired region (electrode overlap region) and maintains uniform light reflectivity for a long time.

  3A to 3C are graphs schematically showing voltage waveforms applied to the ED element during a predetermined period. The horizontal axis represents time, and the vertical axis represents the voltage applied to the ED element.

  As shown in FIG. 3A, a step voltage is periodically applied to the ED element in the first period p1. Here, the step voltage has a waveform in which the first voltage v1 is held for the first time t1, and then the second voltage v2 is held for the second time t2. In the first period p1, the step voltage is applied for at least two cycles. The present inventor accurately forms a deposited ED material film in a desired region (electrode overlap region) when such a voltage is applied to the ED element, and maintains uniform light reflectivity for a long time. A visual evaluation was performed for suitable conditions.

  According to the evaluation by the present inventor, it is generally preferable that the first voltage v1 is higher than the second voltage v2 and that the first time t1 is shorter than the second time t2. I understood. Furthermore, the first voltage v1 is at least equal to or higher than the saturation voltage vs (see FIG. 1D), and the second voltage v2 is larger than 0 [V] and is equal to or lower than the threshold voltage vt (see FIG. 1D). It was found that this is a more preferable condition. In addition, the first time t1 is 1/100 or less of the response time tr (see FIG. 1E), and the second time t2 is within a range of 10 to 1000 times the first time t1. It turned out to be a more desirable condition.

  Specifically, in the embodiment, the first voltage v1 is 3 [V] or more, the first time t1 is 5 [ms] or less, and the second voltage v2 is 0.4 [V] ˜ It was within a range of 1.0 [V], and the second time t2 was preferably within a range of 50 [ms] to 300 [ms]. By periodically applying a step voltage under such conditions, the deposited ED material film is accurately formed in a desired region (electrode overlap region) and is kept uniformly for a long time (for example, 1 minute or more). I found out. In addition, compared with the case where a DC voltage is applied, the light reflectance is higher over the entire visible light region and the light reflection spectrum is flatter when the step voltage having the above-mentioned favorable conditions is applied periodically. I found out that This is presumably because the deposited ED material film has a higher density and a uniform thickness by periodically applying a step voltage under suitable conditions to the ED element.

  Next, the present inventor evaluated the time (rise time) from the application of a periodic step voltage to the ED element until the light reflectance of the ED element is saturated. Here, the first voltage v1 is 10 [V], the first time t1 is 0.4 [ms], the second voltage v2 is 0.4 [V], and the second time A step voltage at which t2 is 50 [ms] is referred to as a step voltage of the first condition. The first voltage v1 is 4 [V], the first time t1 is 2 [ms], the second voltage v2 is 0.6 [V], and the second time t2 is 150. The step voltage that is [ms] is referred to as the step voltage of the second condition.

  According to the evaluation of the present inventor, when the step voltage of the first condition is periodically applied to the ED element, the light reflectance of the ED element is saturated in about 0.5 seconds (that is, the rise time is about 0). .5 seconds). Further, when the step voltage of the second condition was periodically applied to the ED element, the light reflectance of the ED element was saturated in about 3.0 seconds (that is, the rise time was about 3.0 seconds). . From this evaluation, it was found that the rise time of the light reflectance in the ED element was earlier (shorter) when the step voltage of the first condition was periodically applied to the ED element. That is, it has been found that the step voltage under the first condition is more suitable for shortening the rise time of the light reflectance.

  On the other hand, it was found that the light reflectivity of the ED element can be more uniformly maintained for a longer time when the step voltage of the second condition is periodically applied. That is, it has been found that the step voltage under the second condition is a better condition for uniformizing the light reflectivity over a long period of time.

  Based on the above, as shown in FIG. 3B, the step voltage of the first condition is periodically applied in the first period p1, and the step voltage of the second condition is periodically applied in the subsequent second period p2. It may be applied to. That is, as shown in FIG. 3C, for the step voltage applied in the second period p2, the third voltage v3 is held for the third time t3, and then the fourth voltage v4 is maintained for the fourth time t4. When it is assumed that the first voltage v1 is 10 [V], the first time t1 is 0.4 [ms], and the second period p1 (for example, 1 second) A step voltage having a voltage v2 of 0.4 [V] and a second time t2 of 50 [ms] is periodically applied, and in the subsequent second period p2, the third voltage v3 is 4 [V], the third time t3 is 2 [ms], the fourth voltage v4 is 0.6 [V], and the fourth time t4 is 150 [ms]. It may be applied automatically.

  By applying such a voltage to the ED element, the rise time of the light reflectivity can be made faster and the light reflectivity can be kept even for a longer time. That is, the ED element can be switched from the transparent state to the mirror surface state more quickly, and a good mirror surface state can be maintained for a longer time. Note that the numerical values of the various parameters of the step voltage are not limited to the numerical values described above. It can be suitably adjusted according to the production conditions and application of the ED element.

  As shown in FIG. 3C, in the third period p3 after the second period p2, the fifth voltage v5 having a polarity different from that of the first to fourth voltages v1 to v4 is applied to the ED element. May be. By applying such a voltage to the ED element, re-dissolution of the deposited ED material into the electrolyte layer can be promoted. For example, when −0.6 [V] is applied to the ED element as the fifth voltage v5 after periodically applying the step voltage of the second condition in the second period to make the ED element into a mirror surface state, The ED element returns to the transparent state in about 3 seconds.

  FIG. 4A is a cross-sectional view illustrating a modification of the optical device according to the embodiment. In the ED element 101a of the optical device, in the basic structure of the ED element 101, a conductive particle deposition layer 32 is further provided on the upper electrode 22 surface.

  The particle deposition layer 32 is configured, for example, by depositing ITO particles having a particle diameter of 100 [nm] to 500 [nm] with a thickness of about 1.5 μm. For this reason, the surface constitutes fine irregularities and is at least rougher than the surface of the lower electrode 12. The particle deposition layer 32 may be provided on the surface of the lower electrode 12.

  When a negative DC potential is applied to the upper electrode 22 with respect to the potential of the lower electrode 12, a silver thin film (ED material film) is deposited on the particle deposition layer 32 on the surface of the upper electrode 22. When a silver thin film is deposited on the particle deposition layer 32 on which ITO particles of the order of several hundred nm are deposited, the light incident on the ED element 101a is irregularly reflected (or plasmon absorbed) by the silver thin film. In this case, the ED element 101a realizes a light shielding state.

  Thus, by providing the particle deposition layer on the ED element, it is possible to realize a light shielding state in addition to the transparent state and the mirror surface state. Note that a silver thin film may be deposited on the surface of the particle deposition layer 32 by periodically applying a step voltage as shown in FIGS. 3A to 3C to the ED element 101a.

  FIG. 4B is a plan view showing an electrode structure of the ED element. In FIG. 2, a simple matrix type is assumed as the electrode structure of the lower and upper electrodes 12 and 22, but the electrode structure of the lower and upper electrodes 12 and 22 may be a segment type. That is, for example, as shown in FIG. 4B, the lower electrode 12 may have a solid shape, and the upper electrode 22 (shown by a hatched pattern in the drawing) may have a shape corresponding to a character, symbol, figure, or the like.

  As mentioned above, although the form for implementing this invention was demonstrated, this invention is not restrict | limited to these. It will be apparent to those skilled in the art that various modifications, improvements, combinations, and the like can be made.

DESCRIPTION OF SYMBOLS 10 ... Lower substrate, 11 ... Lower base substrate, 12 ... Lower electrode, 20 ... Upper substrate, 21 ... Upper base substrate, 22 ... Upper electrode, 32 ... Particle deposition layer, 40 ... Seal frame member, 50 ... Electrolyte Layer (electrolyte), 101... Electrodeposition element (ED element), 102... Power source, 103.

Claims (6)

First and second substrates disposed opposite to each other, wherein the first substrate includes a first electrode provided on a surface close to the second substrate, and the second substrate includes the first substrate The first and second substrates including a second electrode provided on a surface close to the one substrate;
An electrolyte layer sandwiched between the first and second substrates and containing an electrodeposition material comprising silver;
A power source connected to the first and second electrodes and capable of applying a voltage to the electrolyte layer via the first and second electrodes;
Comprising
The power supply periodically outputs a first step voltage in a first period,
The first step voltage holds a first voltage that is a positive voltage for a first time, and subsequently a second voltage that is a positive voltage and smaller than the first voltage for the first time. A waveform that holds for a longer second time,
The first voltage is 3 V or more, and the first time is 5 ms or less;
The optical device, wherein the second voltage is in a range of 0.4V to 1.0V, and the second time is in a range of 50 ms to 300 ms. First and second substrates disposed opposite to each other, wherein the first substrate includes a first electrode provided on a surface close to the second substrate, and the second substrate includes the first substrate The first and second substrates including a second electrode provided on a surface close to the one substrate;
An electrolyte layer sandwiched between the first and second substrates and containing an electrodeposition material comprising silver;
A power source connected to the first and second electrodes and capable of applying a voltage to the electrolyte layer via the first and second electrodes;
Comprising
The power supply periodically outputs a first step voltage in a first period,
The first step voltage holds a first voltage that is a positive voltage for a first time, and subsequently a second voltage that is a positive voltage and smaller than the first voltage for the first time. A waveform that holds for a longer second time,
When the electrodeposition material is deposited on the surface of the first or second electrode by applying a DC voltage to the electrolyte layer via the first and second electrodes, the electrodeposition material is When the DC voltage that begins to deposit is called the threshold voltage,
The first voltage is at least twice the threshold voltage ;
The optical device, wherein the second voltage is lower than the threshold voltage. The optical apparatus according to claim 2, wherein the first voltage is 2.5 times or less of the threshold voltage. The optical apparatus according to claim 2 or 3, wherein the second time is in a range of 10 to 1000 times the first time. It said power supply, said the second period after the first period, the waveform is different from the first step voltage, claim 2-4 for outputting a second step voltage is a positive voltage periodically The optical device according to claim 1. First and second substrates disposed opposite to each other, wherein the first substrate includes a first electrode provided on a surface close to the second substrate, and the second substrate includes the first substrate The first and second substrates including a second electrode provided on a surface close to the one substrate;
An electrolyte layer sandwiched between the first and second substrates and containing an electrodeposition material comprising silver;
An optical element driving method comprising:
Periodically applying a first step voltage to the electrolyte layer via the first and second electrodes;
The first step voltage holds a first voltage that is a positive voltage for a first time, and subsequently a second voltage that is a positive voltage and smaller than the first voltage for the first time. A waveform that holds for a longer second time,
When the electrodeposition material is deposited on the surface of the first or second electrode by applying a DC voltage to the electrolyte layer via the first and second electrodes, the electrodeposition material is When the DC voltage that begins to deposit is called the threshold voltage,
The first voltage is at least twice the threshold voltage;
The method for driving an optical element, wherein the second voltage is lower than the threshold voltage .