JP7412261B2 - Transmittance variable element and its manufacturing method - Google Patents

Description

The present invention relates to a variable transmittance element and a method for manufacturing the same.

Filters for adjusting the amount or color tone of light incident from the outside are used in various applications such as camera filters, anti-glare mirrors, lighting control filters, and window materials.

As a specific example of such a filter, an example of its use in a video camera for television broadcasting will be described with reference to FIG. In the video camera 1, when adjusting the amount of light 6 that enters the imaging surface of the image sensor 5, the aperture diameter (F number) of the aperture 3 of the lens 2 is changed to adjust the brightness of the output image on the image sensor 5. (signal amount). Here, if the value of the aperture 3 of the lens 2 is changed, not only will the brightness change, but also the distance in the depth direction of focus (depth of field) and resolution will also change. In particular, in recent 4K and 8K high-definition television systems, if the diameter of the aperture 3 of the lens 2 is made smaller than a certain value, image blur (called "small aperture blur") due to light diffraction occurs. , the resolution of the acquired images may be significantly reduced. Therefore, in order to adjust the light intensity of the light 6, in addition to adjusting the light intensity by adjusting the F value of the lens 2, multiple ND (Neutral Density) filters 4 with different transmittances are used in order to further attenuate the light intensity. Then, select and use one ND filter with appropriate transmittance for the light amount situation.

Incidentally, in recent years, variable transmittance elements have been developed that can change the spectral transmission characteristics steplessly and continuously by applying a voltage. For example, Patent Document 1 discloses that a substrate with a transparent conductive film, which is a glass substrate with a transparent conductive film formed thereon, is provided with an electrode pair with the transparent conductive film sides facing each other, and in the gap between the electrode pair, A variable reflectance element is disclosed that is filled with an electrolytic solution in which silver and copper, which serve as metal salts, are dissolved in methanol. In this device, by changing the electric field between the electrode pair, it is possible to reversibly repeat the deposition or dissolution of silver ions on the surface of the transparent conductive film, so the light transmittance can be adjusted steplessly. It can be changed.

International Publication No. 2015/093298

For example, considering a video camera for television broadcasting, if the conventional ND filter 4 described above can be replaced with a variable transmittance element, it can be expected to be an effective countermeasure against the "light diffraction phenomenon" described above. This is because the light transmittance of the variable transmittance element can be arbitrarily adjusted steplessly while setting the aperture size (F value) that provides excellent resolution of the lens. The use of variable transmittance elements can also be expected when a single video camera is used to continuously capture a mixture of high illumination, such as outdoors on a clear day, and low illumination, such as indoors. In such cases, if you only adjust the F value of the lens to maintain high resolution, you will not be able to sufficiently attenuate the brightness under high illumination, and an excessive amount of light will enter the imaging surface. However, if a transmittance conversion element is used, the transmittance can be changed steplessly and quickly, so it is easy to adjust the amount of light that enters the photographing surface. In addition, with the conventional ND filter 4, when selecting and switching between multiple transmittance filters, the frame (turret part) is reflected in the output image, but with the transmittance variable element, the frame (turret part) is reflected in the output image. Since it can be adjusted, it also has the advantage of not requiring switching.

However, in the element described in Patent Document 1, since reflection and transmission of light act in a complex manner, changing the light transmittance also affects the light reflection component, which may change the color tone, and there is still room for improvement. be.

Therefore, an object of the present invention is to provide a variable transmittance element that can suppress the influence on color tone change even when used under sunlight (corresponding to a color temperature of 5600K to 7200K), and a method for manufacturing the same.

In order to solve the above problems, the present inventors conducted extensive studies and defined the transmittance characteristics of the variable transmittance element with respect to the wavelength of incident light. The gist of the present invention is as follows.

The variable transmittance element according to the present invention includes an electrode pair composed of a first and a second transparent conductive film-coated substrate arranged in a pair with a gap therebetween, and a composition of which is filled in the gap and contains silver ions. an electrolytic solution, and the silver ions in the electrolytic solution are deposited on the surface of the first light-transmitting conductive film-coated substrate to change the light transmittance according to changes in the electric field between the electrode pair. In this case, the spectral transmission characteristics in the visible light region change steplessly while maintaining a state that matches the correction characteristics corresponding to 5600K to 7200K under sunlight.

In this variable transmittance element, the transmittance at a wavelength of 635 nm is expressed as T _R , the transmittance at a wavelength of 520 nm is expressed as T _G , and the transmittance at a wavelength of 430 nm is expressed as T _B , and the light transmittance is changed according to the change in the electric field. It is preferable that the ratio of the respective transmittances is in the range of T _R :T _G :T _B =1:1 to 0.65:0.80 to 0.45.

Further, in the variable transmittance element according to the present invention, it is preferable that the surface resistivity of the light-transmitting conductive film in the first and second substrates with the light-transmitting conductive film are both 5Ω/□ to 30Ω/□.

Furthermore, in the variable transmittance element according to the present invention, it is preferable that the thicknesses of the transparent conductive films in the first and second substrates with transparent conductive films are both 100 nm to 250 nm.

Further, the method for manufacturing a variable transmittance element according to the present invention includes a step of forming substrates with first and second transparent conductive films, and a step of forming substrates with the first and second transparent conductive films with a gap therebetween. a step of arranging a substrate and providing a pair of electrodes constituted by the first and second transparent conductive film-coated substrates; and silver ions and copper ions whose content is smaller than the silver ions in the gap. A method for manufacturing a variable transmittance element, comprising: filling an electrolytic solution having a composition thereof, the method comprising: filling an electrolytic solution with a composition of The first and second transparent conductive films are formed on the first and second substrates by sputtering at a rate of .4 sccm to 0.7 sccm, respectively.

In this specification, the symbol "~" used to indicate a numerical range includes the numerical values at both end points of the range. For example, the notation of the numerical range "1 to 10" can be rephrased as 1 or more and 10 or less.

According to the present invention, it is possible to provide a variable transmittance element that can suppress the influence on color tone change even when used under sunlight (equivalent to a color temperature of 5600K to 7200K), and a method for manufacturing the same.

1 is a schematic diagram of a video camera according to the prior art; FIG. FIG. 1 is a schematic cross-sectional view of a variable transmittance element according to an embodiment of the present invention. 2 is a graph showing the spectral transmission characteristics of the substrate with a transparent conductive film produced in Example 1. 2 is a graph showing the transmittance characteristics when changing the transmittance of the variable transmittance element produced in Example 1, (A) is a graph in which the vertical axis is a linear scale, and (B) is a graph in which the vertical axis is a linear scale. It is on a logarithmic scale. 2 is a graph showing the transmittance characteristics when changing the transmittance of the variable transmittance element produced in Comparative Example 1, (A) is a graph in which the vertical axis is a linear scale, and (B) is a graph in which the vertical axis is a linear scale. It is on a logarithmic scale.

(Transmittance variable element)
Hereinafter, an embodiment of a variable transmittance element according to the present invention will be described with reference to FIG. 2. A variable transmittance element 100 according to an embodiment of the present invention includes an electrode pair constituted by a pair of first and second transparent conductive film-coated substrates 110 and 120 arranged with a gap in between, and a pair of electrodes that are filled in the gap. and an electrolytic solution 140 containing silver ions in its composition, and may further include other configurations as necessary. Then, in the variable transmittance element 100, silver ions in the electrolytic solution 140 are deposited on the surface of the first transparent conductive film-coated substrate 110 in response to changes in the electric field between the electrode pair, thereby changing the light transmittance. When the change is made, the spectral transmission characteristics in the visible light region of the first substrate 110 with a transparent conductive film change steplessly while maintaining a state that matches the correction characteristics equivalent to 5600K to 7200K under sunlight. do. For convenience of explanation, the substrate with a transparent conductive film on the incident light 310 side will be referred to as the "first substrate with a transparent conductive film 110", and the substrate with a transparent conductive film on the side of the transmitted light 320 will be referred to as "the first substrate with a transparent conductive film on the side of the transmitted light 320". "Second transparent conductive film-coated substrate 120". The details of each configuration will be sequentially explained below.

<Electrode pair>
An electrode pair is formed by arranging the first substrate 110 with a transparent conductive film and the second substrate 120 with a transparent conductive film in a pair with a predetermined gap in between. The first and second transparent conductive film-coated substrates 110 and 120 are first and second substrates 111 and 121, respectively, and first and second transparent conductive films 112 provided on each substrate, It has 122. Then, the first and second transparent conductive films 112 and 122 are arranged to face each other.

<<Substrate>>
Each of the first and second substrates 111 and 121 may be a glass substrate or a resin substrate. Both may be of the same type of material or may be of different types of materials. There are no limitations on the material as long as a transparent conductive film can be formed on the surface of each substrate.

<<Transparent conductive film>>
Each of the first and second transparent conductive films 112 and 122 is a transparent conductive film made of, but not limited to, ITO (indium tin oxide), IZO (indium zinc oxide), tin oxide, zinc oxide, or the like. It is preferable. Among the light-transmitting conductive films, it is more preferable to use ITO. Note that each light-transmitting conductive film may be made of the same kind of material or may be made of different kinds of materials. There are no limitations on the material as long as silver can be deposited on the surface of each light-transmitting conductive film.

--Surface resistivity--
It is desirable that the surface resistivity of each of the first and second transparent conductive films 112 and 122 is as low as possible, and it is desirable that the surface resistivity is 5Ω/□ to 30Ω/□, which can be practically formed. Among these, it is preferable to set it to 30Ω/□ or less. Surface resistivity affects the response when changing the transmittance by applying an electric field between the electrode pair, and if the surface resistivity is 30Ω/□ or less, the speed of changing the transmittance is sufficient. If the surface resistivity is 100Ω/□ or more, silver ions cannot be deposited. The surface resistivities of both transparent conductive films may be the same or different.

--Film thickness--
The thickness of each of the first and second light-transmitting conductive films 112 and 122 is not particularly limited, and may be set to an appropriate thickness depending on the application, but may be 100 nm to 250 nm, for example. . Since the film thickness of each light-transmitting conductive film affects the above-mentioned surface resistivity and transmittance, it may be appropriately designed in consideration of desired spectral transmittance characteristics and transmittance variable speed. The film thicknesses of both transparent conductive films may be the same or different. However, if the film is made thicker, the maximum transmittance may become lower, so it is preferable to take into account the variable range of transmittance and response speed (resistance value) when designing.

<Electrolyte>
It is also preferable that the electrolytic solution 140 contains silver ions in its composition and, if necessary, contains copper ions whose content is less than silver ions. Such an electrolytic solution 140 is, for example, a non-aqueous solvent containing an ester solvent such as propylene carbonate and an alcohol such as methanol, a silver salt such as silver nitrate (AgNO ₃ ), and a copper such as cupric chloride (CuCl ₂ ). Obtained by dissolving salt. A supporting electrolyte such as lithium bromide (LiBr) may be further dissolved in the non-aqueous solvent, if necessary. The electrolytic solution 140 may further contain a thickener as necessary. Examples of such thickeners are polymers such as polypropylene, polyvinyl butyral, polymethyl methacrylate. The electrolytic solution 140 is filled in the gap between the electrode pair formed by the first and second transparent conductive film coated substrates 110 and 120.

<Other configurations>
In order to fill the gap between the electrode pair with the electrolytic solution 140, the variable transmittance element 100 may include sealants 171 and 172 that seal the electrolytic solution 140. Further, the variable transmittance element 100 may include a drive power source 200 electrically connected to the first and second substrates 110 and 120 with transparent conductive films. The sealing materials 171 and 172 are made of the same material as the first and second substrates 111 and 121 (glass or resin substrates, etc.), and the substrates 110 and 120 are made of a substance with an adhesive effect and have a transparent conductive film. All you have to do is form a closed space. Furthermore, the drive power supply 200 can be operated using a general DC power supply, but in order to further improve the response and maintain the specified transmittance for a long time, it is also possible to separately provide a negative feedback circuit that can detect the transmittance. good.

Here, a change in transmittance due to the formation of the precipitated layer 150 in the variable transmittance element 100 will be explained. The first substrate 110 with a transparent conductive film on the incident light 310 side is used as a cathode (-), and the opposite side of the substrate 120 with a second transparent conductive film is used as an anode (+) at 2.5V. When a certain voltage is applied by the drive power supply 200, the silver ions that have dissolved in the electrolytic solution 140 and are colorless and transparent are transferred from the transparent conductive film to the entire surface of the transparent conductive film 112 on the side of the incident light 310. Upon receiving electrons, a reduction action occurs, and silver (metal) is precipitated to form the deposited layer 150. The variable transmittance element 100 has a precipitated layer 150 formed thereon, and as the thickness of the precipitated layer 150 increases, the transmittance of light passing through the variable transmittance element 100 can be arbitrarily and steplessly attenuated. Furthermore, if the polarity of the potential supplied to the drive power source 200 is reversed, the silver crystal grains deposited in the deposited layer 150 will be eluted into the electrolytic solution 140, increasing the transmittance. Specifically, the side of the first substrate 110 with a transparent conductive film on the incident light 310 side is used as an anode (+), and the side of the second substrate 120 with a transparent conductive film on the opposite side is used as a cathode (- ), when a voltage of about 0.5 V is applied, the silver crystal grains deposited in the deposited layer 150 are oxidized and become silver ions in the electrolytic solution 140, returning to a transparent state. By repeating this precipitation and elution in the variable transmittance element 100, the transmittance of the variable transmittance element 100 can be changed at will.

<Spectral transmittance>
Now, the variable transmittance element 100 according to the present invention transfers silver ions in the electrolytic solution 140 to the surface of the first transparent conductive film-coated substrate 110 (in particular, the first transparent When depositing on the photoconductive film 112) to change the light transmittance, the spectral transmission characteristics in the visible light region can be changed steplessly while maintaining the correction characteristics equivalent to 5600K to 7200K under sunlight. change to Here, the "correction characteristics equivalent to 5600K to 7200K under sunlight" means that in the visible light region (approximately wavelength range 380nm to 750nm), the emission wavelength of the sunlight component decreases as the wavelength increases (blue area>green area>red area), it refers to the balance of spectral transmission characteristics corrected to the emission component of the emission wavelength of studio lighting (tungsten light source) 3200K (blue area<green area<red area). That is, it means that the transmittance satisfies the blue light region<green light component≦red region. If the spectral transmission characteristics satisfy this tendency, for example, when the variable transmittance element 100 is used in a video camera for television broadcasting to take pictures, even if it is used under sunlight, changes in color tone can be suppressed. . Therefore, the variable transmittance element 100 can be used as a filter that attenuates transmittance while adjusting the color balance over the entire visible light range.

-Transmittance ratio-
In order to satisfy the above-mentioned correction characteristics, the transmittance at a wavelength of 635 nm is expressed as T _R , the transmittance at a wavelength of 520 nm is expressed as T _G , and the transmittance at a wavelength of 430 nm is expressed as T _B , and the light transmittance is adjusted according to the change in the electric field. It is preferable that the ratio of each transmittance when changing is in the range of T _R :T _G :T _B =1:1 to 0.65:0.80 to 0.45. Even if the transmittance of the variable transmittance element 100 is increased or decreased, as long as each transmittance is within the range of the above ratio, when considering use under sunlight, the effect on the desired color tone can be adjusted while adjusting the light amount. can be sufficiently suppressed. In addition, if the light intensity of the green light component is attenuated too much, the transmittance will be greatly attenuated even when no silver precipitation phenomenon occurs, which may narrow the light intensity adjustment range (from maximum transmission to maximum attenuation). Therefore, a more preferable ratio of each transmittance is T _R :T _G :T _B =1:1 to 0.70:0.6 to 0.5. Further, in order to satisfy the above-mentioned correction characteristics, it is preferable that T _R > T _G > T _B. Further, it is most preferable that the transmittance variable element 100 according to the present invention satisfies the above transmittance ratio over the entire range in which the transmittance can be adjusted. The above transmittance ratio may be satisfied when the transmittance is increased or decreased within the range of (low precipitation). Note that the ratio at which the transmittance is increased or decreased is based on the transmittance at a wavelength of 520 nm in a non-precipitated state.

As described above, in the variable transmittance element 100 according to the present invention, the transmittance characteristics with respect to the wavelength of incident light are defined. This variable transmittance element can suppress the influence on color tone change, especially when used under sunlight (equivalent to a color temperature of 5600K to 7200K). In particular, if this variable transmittance element 100 is used in a video camera for television broadcasting, even if the transmittance is changed during camera shooting under sunlight, the variable transmittance can be controlled while always suppressing the effect on the color balance. It can be realized. Although it is preferred that a video camera is equipped with a variable transmittance element according to the invention, this is only one example of the use of the variable transmittance element according to the invention. The variable transmittance element according to the present invention can be applied to various uses such as filters for video cameras, filters for general cameras, anti-glare mirrors, dimming filters for lighting, and window materials. Note that the size and shape (round, rectangular, etc.) of the variable transmittance element 100 according to the present invention are not limited in any way, but as the element area increases, the response performance decreases. It is preferable to design the size and shape of the element.

(Method for manufacturing transmittance conversion element)
Next, an embodiment of a method for manufacturing the variable transmittance element 100 according to the present invention described above will be described. Continuing to refer to FIG. The method for manufacturing the variable transmittance element 100 includes the steps of forming first and second substrates 110 and 120 with transparent conductive films, and forming the first and second substrates 110 with transparent conductive films with a gap in between. , 120, and providing a pair of electrodes constituted by the first and second substrates 110 and 120 with transparent conductive films, and applying an electrolytic solution containing silver ions in the gap between the electrode pairs. 140. Other steps may be included as necessary. In addition, in the embodiment of the variable transmittance element 100, the structures already described are given the same reference numerals, and redundant explanations will be omitted.

<Step of forming a substrate with a transparent conductive film>
First, first and second substrates 110 and 120 with transparent conductive films are formed, respectively. Both substrates may be formed simultaneously or separately. Here, in this step, the first and second transparent conductive films 112 and 122 are formed on the first and second substrates 111 and 121 by sputtering with an oxygen introduction amount of 0.4 sccm to 0.7 sccm. Each film is formed. An appropriate sputtering target may be selected depending on the material of the transparent conductive film to be formed.

<<Sputtering conditions>>
As mentioned above, the amount of oxygen introduced in the sputtering method is set to 0.4 sccm to 0.7 sccm. The oxygen flow rate has a particularly large effect on the transmission characteristics in the blue light region among the visible light regions. When the oxygen flow rate is lower than this range, the transmittance in the blue region is significantly attenuated, and furthermore, the transmittance in the entire visible light region is attenuated. Furthermore, if the oxygen flow rate is increased beyond this range, only the transmittance in the blue light region will improve from around 0.7 sccm, so if the variable transmittance element is operated in a region with high transmittance, the color tone will be unbalanced. . Furthermore, if the amount of oxygen is reduced below 0.4 sccm, cloudiness will occur on the surface of the transparent conductive film, making it unsuitable for image quality in video cameras for television broadcasting.

Other sputtering conditions in the sputtering method can be carried out under general conditions other than the above-mentioned oxygen introduction amount range, and in addition to oxygen, an inert gas such as argon may be introduced at about 10 to 150 sccm. In this case, the ratio of the oxygen flow rate (introduced amount) to the inert gas flow rate (ie, oxygen flow rate/inert gas flow rate) is preferably about 0.00267 to 0.07, and about 0.008 to 0.014. It is more preferable that Further, the degree of vacuum is preferably a medium vacuum of about 0.1 Pa to 1.0 Pa. Although it is preferable to use a DC sputtering method, an RF sputtering method or the like may also be used. By adjusting the film formation time, it is possible to adjust the thickness of the transparent conductive film, its surface resistivity, and its transmittance in a non-precipitated state.

Next, an electrode pair is provided using the first and second substrates 110 and 120 with transparent conductive films. Then, the gap between the electrode pairs may be filled with the electrolytic solution 140. Sealing materials 171 and 172 may be used to fill the gap with electrolyte 140. Prior to filling the electrolytic solution 140, a step of preparing the electrolytic solution 140 may be performed.

The variable transmittance element according to the present invention can be manufactured by going through each step including the above-described optional steps. The thus obtained variable transmittance element can suppress the influence on color tone change even when used especially under sunlight (equivalent to a color temperature of 5600K to 7200K).

Hereinafter, the present invention will be explained in more detail using Examples, but the present invention is not limited to the following Examples.

(Example 1)
For convenience of explanation, reference is made to the reference numerals in FIG. Transparent conductive films 112 and 122 made of ITO were formed on glass substrates 111 and 121, respectively. For film formation, a DC sputtering method was used and an ITO (tin 5% by weight) target was used. The sputtering conditions were an oxygen flow rate of 0.4 sccm, an argon flow rate of 50 sccm, and a vacuum degree of 0.6 Pa. Then, each light-transmitting conductive film 112, 122 was obtained by film formation at DC 260W for 10 minutes. The surface resistivity of each of the obtained translucent conductive films (measured using the 4-terminal 4-deep needle method (constant current application) with MCP-T370 manufactured by Nitto Seiko Analytech) was 28.3Ω/□, and the film thickness (reflection) was 28.3Ω/□. (measured with a spectrometer) was 160 nm. In addition, in the sputtering apparatus used in this example, when the amount of oxygen introduced was changed to 0.8 sccm, and when ITO was formed with a film thickness of 160 nm as in this example, the surface resistivity of the film was 15 Ω/ It becomes □. Further, the sizes of the first substrate 111 and the second substrate 121 are both 34 mm x 50 mm.

These transparent conductive film-coated substrates 110 and 120 were arranged in a pair with a gap therebetween to provide an electrode pair. Next, the inside of the gap between the electrode pairs was filled with an electrolytic solution 140 having a composition containing silver ions and copper ions containing less weight than the silver ions. In order to prevent the electrolytic solution 140 from leaking, the glass substrate 111 on the incident light 310 side, the glass substrate 121 on the transmitted light 320 side, and sealing materials 171 and 172 with a thickness of 0.3 mm were used to seal the structure. Transparent conductive films 112 and 122 are facing each other, and their surfaces are in contact with electrolyte 140. In this way, the variable transmittance element 100 according to Example 1 was manufactured.

FIG. 3 shows the transmittance characteristics of a single substrate with a light-transmitting conductive film made of ITO produced in Example 1. A transmittance meter (manufactured by Otsuka Electronics Co., Ltd.: MCPD-3700) was used for transmittance measurement. The same applies to the following evaluations. Table 1 below shows the overall transmittance balance of the substrate with a transparent conductive film when used as an electrode pair.

The transmittance of the entire variable transmittance element is affected by the balance of spectral transmission characteristics of the entire element including the glass substrate and the like. Therefore, when the variable transmittance element according to Example 1 is driven to form a deposited layer, the spectral transmittance characteristics are shown when the transmittance at a wavelength of 550 nm is varied in steps of 10% in the range of 60 to 10%. 4. 4(A) shows the vertical axis on a linear scale, and FIG. 4(B) shows the vertical axis on a logarithmic scale. Even when the variable transmittance element according to Example 1 was driven to vary the transmittance based on a wavelength of 550 nm, the balance of spectral transmittance characteristics remained the same, and the color temperature of sunlight (5600K to 7200K) was corrected. It can be confirmed that the same trend is observed in balance (transmittance decreases in the order of red, green, and blue). Therefore, if this variable transmittance element is used in a video camera, it can be used as a filter that attenuates the transmittance while adjusting the color balance over the entire visible light range.

(Comparative example 1)
In Example 1, a transparent conductive film made of ITO was formed at an oxygen flow rate of 0.4 sccm, and the transmittance according to Comparative Example 1 was obtained in the same manner as in Example 1 except that the oxygen flow rate was changed to 0.8 sccm. A variable element was fabricated. The surface resistivity of the transparent conductive film in Comparative Example 1 was 14.9Ω/□, and the film thickness was 160 nm.

FIG. 5 shows the spectral transmission characteristics when the transmittance variable element according to Comparative Example 1 is driven and the transmittance at a wavelength of 550 nm is varied to 60%, 40%, and 10%. 5(A) shows the vertical axis on a linear scale, and FIG. 5(B) shows the vertical axis on a logarithmic scale. In Comparative Example 1, especially when the transmittance (550 nm transmittance standard) is changed from 40% to 10%, the spectral transmittance of 10% is strongly influenced by the reflected light component rather than the transmitted light. There was a swell in the spectral transmission characteristics. If this is used in a video camera, the color tone will change as well as the transmittance. In other words, the balance of spectral transmission characteristics is disrupted and color reproducibility is adversely affected.

Comparing Example 1 and Comparative Example 1, the reason why the color balance becomes uneven in Comparative Example 1 is that the blue transmission of the transparent conductive film is extremely high transmission compared to other colors. This is thought to be because it had It is considered that this problem does not occur in Example 1 because the oxygen flow rate during ITO film formation was reduced. Furthermore, due to the effect of suppressing the reflected light component even if more silver was precipitated, the structure of Example 1 was also characterized in that red transmission tended to be more attenuated than in Comparative Example 1. . It is thought that by adjusting the balance of the blue component transmittance of the transparent conductive film, it also affected the red component of reflected light.

According to the present invention, it is possible to provide a variable transmittance element and a method for manufacturing the same, which can suppress the influence on color tone change even when used under sunlight (equivalent to a color temperature of 5600K to 7200K), and a method for manufacturing the same. It is particularly useful in a variety of filter applications where

Transmittance variable element 100
First substrate with transparent conductive film 110
First substrate 111
First transparent conductive film 112
Second substrate with transparent conductive film 120
Second board 121
Second transparent conductive film 122
Electrolyte 140
Precipitated layer 150
Sealing material 171, 172
Power supply 200
Incident light 310
Transmitted light 320

Claims (5)

an electrode pair constituted by first and second transparent conductive film-coated substrates arranged in a pair with a gap therebetween;
an electrolytic solution filled in the gap and containing silver ions in its composition;
A variable transmittance element comprising:
When the silver ions in the electrolytic solution are deposited on the surface of the first transparent conductive film-coated substrate in response to a change in the electric field between the electrode pair and the light transmittance is changed, visible light Spectral transmission characteristics within the region include a state in which, in the transmission spectral transmission characteristics, the transmittance in the blue light region is smaller than the transmittance in the green region, and the transmittance in the green region is less than or equal to the transmittance in the red region. A variable transmittance element that is characterized by changing steplessly while maintaining the same level of transmittance. The transmittance at a wavelength of 635 nm is represented by T _R , the transmittance at a wavelength of 520 nm is represented by T _G , and the transmittance at a wavelength of 430 nm is represented by T _B , and each transmittance when the light transmittance is changed according to the change in the electric field. The variable transmittance element according to claim 1, wherein the ratio of T _R :T _G :T _B is in the range of 1:1 to 0.65:0.80 to 0.45. 3. The variable transmittance element according to claim 1, wherein the light-transmitting conductive films in the first and second substrates with light-transmitting conductive films both have a surface resistivity of 5Ω/□ to 30Ω/□. The variable transmittance element according to claim 1, wherein the transparent conductive films in the first and second substrates with transparent conductive films both have a thickness of 100 nm to 250 nm. forming first and second substrates with transparent conductive films;
arranging the first and second transparent conductive film-coated substrates with a gap between them, and providing a pair of electrodes constituted by the first and second transparent conductive film-coated substrates;
filling the gap with an electrolytic solution containing silver ions and copper ions whose content is lower than the silver ions;
A method for manufacturing a variable transmittance element comprising:
In the step of forming the first and second substrates with transparent conductive films, the first and second substrates are coated on the first and second substrates by sputtering with an oxygen introduction amount of 0.4 sccm to 0.7 sccm. 1. A method for manufacturing a variable transmittance element, comprising forming two transparent conductive films.

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