阅读说明：本技术 柔性电致变色器件 (Flexible electrochromic device ) 是由 吴丞培 罗龙祥 李成焕 沈钟珉 刘日焕 安秉煜 于 2021-06-04 设计创作，主要内容包括：本发明的实例涉及一种电致变色器件,其基于电致变色原理实现优异的透光率可变功能的同时具有柔软性,在上述电致变色器件中,透光率可变结构体介于第一基底层和第二基底层之间,上述透光率可变结构体包括第一变色层及第二变色层,在式(1)中定义的△TTd-(24)值为3％以下。(An embodiment of the present invention relates to an electrochromic device having flexibility while realizing an excellent light transmittance variable function based on an electrochromic principle, in which a light transmittance variable structure including a first color-changing layer and a second color-changing layer, Δ TTd defined in formula (1), is interposed between a first substrate layer and a second substrate layer 24 The value is 3% or less.)

1. An electrochromic device, characterized in that,

the light transmittance variable structure is interposed between the first substrate layer and the second substrate layer,

the light transmittance variable structure comprises a first color changing layer and a second color changing layer,

Δ TTd defined in the following formula (1)₂₄The value of the content is 3% or less,

△TTd₂₄(％)＝│TTd₂₄－TTd₀│...(1)

in the above-mentioned formula (1),

TTd₀in order that the above electrochromic device has a curvature radius of 17R after being deformed and then when a power source is applied, the visible light average transmittance (%) in the maximum discolored state,

TTd₂₄in order to measure the above TTd₀Then, the power was turned off, and the above electrochromic device was deformed into a state having a curvature radius of 17R and maintained for 24 hours, and then the visible light average transmittance (%) was measured.

2. The electrochromic device according to claim 1,

Δ TTc defined in the following formula (2)₂₄The value of the content is 2% or less,

△TTc₂₄(％)＝│TTc₂₄－TTc₀│...(2)

in the above-mentioned formula (2),

TTc₀in order to apply power after the electrochromic device described above was deformed so as to have a curvature radius of 17R, the average transmittance (%) of visible light in the maximum coloring state,

TTc₂₄in order to measure the above TTc₀Then, the power was turned off, and the above electrochromic device was deformed into a state having a curvature radius of 17R and maintained for 24 hours, and then the visible light average transmittance (%) was measured.

3. The electrochromic device according to claim 1,

the TTRdc value defined in the following formula (3) is 90% or more,

TTRdc(％)＝(△TTdc₂₄/△TTdc₀)×100...(3)

in the above-mentioned formula (3),

△TTdc₀showing the difference (%) between the average transmittance of visible light in the maximum discolored state and the average transmittance of visible light in the maximum colored state when power is applied after the above electrochromic device has been deformed so as to have a radius of curvature of 17R,

△TTdc₂₄is shown in the measurement of the above-mentioned Δ TTdc₀After that, when the power was turned off and the above electrochromic device was deformed into a state having a radius of curvature of 17R and held for 24 hours, the difference (%) between the average transmittance of visible light in the maximum discolored state and the average transmittance of visible light in the maximum colored state was observed.

4. The electrochromic device according to claim 1, characterized in that no cracks are generated in the state of deformation to have a radius of curvature of 70R.

5. The electrochromic device according to claim 1, characterized in that the first coloring layer comprises 2 to 12 parts by weight of the polymeric resin based on 100 parts by weight of the reductive coloring matter.

6. The electrochromic device according to claim 1,

the first color-changing layer contains a reductive color-changing substance,

the second color-changing layer contains an oxidative color-changing substance,

the first color changing layer and the second color changing layer are formed by wet coating.

7. An electrochromic device comprising a first substrate layer, a second substrate layer, and a light transmittance variable structure interposed therebetween, the light transmittance variable structure comprising a first color-changing layer capable of adjusting coloring and fading by application of a power source, characterized in that,

when a bending test is repeated in which the test piece of the electrochromic device having a dimension of 300mm in width and 200mm in length is bent so that the distance between both lateral ends is 75mm and then developed to restore the original shape, the first light transmittance change Δ TT _ B30 defined in the following formula (i) is 1.5% or less,

△TT_B30(％)＝│TT_B30－TT_0│...(i)

in the above-mentioned formula (i),

TT _ B30 is the average transmittance (%) of visible light of the above electrochromic device measured in the maximum fading state after repeating the above bending test 30 times,

TT — 0 is the visible light average transmittance (%) of the above electrochromic device measured in the maximum fading state before the above bending test was performed.

8. The electrochromic device according to claim 7,

when the above-mentioned electrochromic device is subjected to the above-mentioned bending test repeatedly, the second light transmittance change Δ TT _ B30_ d defined in the following formula (ii) is 3% or less,

△TT_B30_d(％)＝││TT_B30－TT_B30'│－│TT_0－TT_0'││...(ii)

in the above-mentioned formula (ii),

TT _ B30 is the average transmittance (%) of visible light of the above electrochromic device measured in the maximum fading state after repeating the above bending test 30 times,

TT _ B30' is the average transmittance (%) of visible light of the above electrochromic device measured in the maximum coloring state after repeating the above bending test 30 times,

TT — 0 is the visible light average transmittance (%) of the above electrochromic device measured in the maximum discolored state before the above bending test was performed,

TT — 0' is the visible light average transmittance (%) of the above electrochromic device measured in the maximum coloring state before the above bending test was performed.

9. The electrochromic device according to claim 7,

when the above-mentioned electrochromic device is subjected to the above-mentioned bending test repeatedly, the third light transmittance change Δ TT _ B50 defined in the following formula (iii) is 3% or less,

△TT_B50(％)＝│TT_B50－TT_0│...(iii)

in the above-mentioned formula (iii),

TT _ B50 is the average transmittance (%) of visible light of the above electrochromic device measured in the maximum fading state after repeating the above bending test 50 times,

TT — 0 is the visible light average transmittance (%) of the above electrochromic device measured in the maximum fading state before the above bending test was performed.

10. The electrochromic device according to claim 7,

the first base layer and the second base layer are polymer films,

the thickness of the first color changing layer is 300nm to 600nm,

the thickness of the electrochromic device is 20 μm to 1000 μm.

Technical Field

An embodiment of the present invention relates to an electrochromic device that realizes an excellent light transmittance variable function based on an electrochromic principle while having flexibility.

Background

Recently, as the interest in environmental protection has increased, the interest in improving energy efficiency has also increased. As an example, research and development of technologies such as smart window (smart window), energy harvesting (energy harvesting), and the like are actively being performed. Among them, the smart window refers to an active control technology that can improve energy efficiency and provide a comfortable environment for a user by adjusting a transmission degree of light from the outside, and is a common technology that can be generally applied to various industrial fields. Such smart windows take electrochromism, which is a phenomenon in which an electrochemical oxidation or reduction reaction occurs by an applied power source, whereby optical characteristics, such as inherent color or transmittance, of an electrochromic active material are changed, as a basic principle.

Currently, a glass type smart window using an electrochromic device between several sheets of glass is generally used, but it is difficult to commercialize the smart window because the manufacturing process is complicated and the price of the product is very expensive due to the customization of the product according to the size of the window to be constructed. In addition, in the case of ending with silicon, there is a risk of electric leakage due to moisture permeation, and a large storage space is occupied during logistics transportation, while there is a problem that it is fragile and dangerous when being subjected to external impact due to the material characteristics of glass.

Therefore, there is a continuing need for research into smart windows that can achieve an excellent transmittance variable function while solving the above-mentioned problems.

Documents of the prior art

Prior patent 1: korean granted patent No. 1862200 (2018.5.23).

Disclosure of Invention

An example of the present invention is directed to providing an electrochromic device that realizes an excellent light transmittance variable function based on an electrochromic principle while having flexibility.

According to an example of the present invention, there is provided an electrochromic device in which a light transmittance variable structure including a first color changing layer and a second color changing layer is interposed between a first substrate layer and a second substrate layer, Δ TTd defined in the following formula (1)₂₄The value is 3% or less.

△TTd₂₄(％)＝│TTd₂₄－TTd₀│...(1)

In the above formula (1), TTd₀Average transmittance (%) of visible light, TTd in maximum discolored state when power is applied after deformation such that the above electrochromic device has a radius of curvature of 17R₂₄In order to measure the above TTd₀Then, the power was turned off, and the above electrochromic device was deformed into a state having a curvature radius of 17R and maintained for 24 hours, and then the visible light average transmittance (%) was measured.

According to another example of the present invention, there is provided an electrochromic device including a first substrate layer, a second substrate layer, and a light transmittance variable structure interposed therebetween, the light transmittance variable structure including a first color-changing layer capable of adjusting coloring and fading by applying a power source, characterized in that,

when a bending test in which the test piece of the electrochromic device having a dimension of 300mm in width and 200mm in length is repeatedly bent to make the distance between both lateral ends 75mm and then developed to restore the original shape is repeated, the first light transmittance change (Δ TT _ B30) defined in the following formula (i) is 1.5% or less,

△TT_B30(％)＝│TT_B30－TT_0│...(i)

in the above-mentioned formula (i),

TT _ B30 is the average transmittance (%) of visible light of the electrochromic device measured in the maximum fading state after the bending test was repeated 30 times, and TT _0 is the average transmittance (%) of visible light of the electrochromic device measured in the maximum fading state before the bending test was performed

The electrochromic device according to the above example realizes an excellent transmittance variable function based on the electrochromic principle while having a soft characteristic. In particular, the above electrochromic device can be deformed to have a small radius of curvature, and can realize an excellent light transmittance variable function not only in the deformed state but also after the deformed state has continued for several hours. And the above electrochromic device can continue to maintain the light transmittance operation function with almost no change in light transmittance compared to the initial state even when repeatedly bent or kept in a bent state for a long time or when the power is turned off for a long time.

Therefore, the electrochromic device can be applied to a curved window without degrading performance, and can be applied to a curved portion or a portion with a large movement in the fields of electronic equipment, automobiles, buildings, and the like. Further, the electrochromic device can be rolled into a roll shape by using its flexibility, thereby providing convenience in manufacturing processes, transportation, installation, and the like, and having excellent workability, and can be easily cut and adhered to fit windows of various sizes.

Drawings

Fig. 1 is a perspective view conceptually showing an electrochromic device according to an example of the present invention applied to a window.

Fig. 2 is a sectional view taken along line a-a' of fig. 1 and an enlarged view thereof.

Figure 3 schematically shows a cross-section of an electrochromic device according to an example of the invention.

Fig. 4 schematically shows a cross section of an electrochromic device and a light transmittance variable structure according to an example of the present invention.

Figure 5 schematically shows a cross-section of an electrochromic device and a barrier layer according to an example of the invention.

Fig. 6 schematically shows a cross-section of an electrochromic device according to an example of the invention.

Fig. 7 shows a bending test in which an electrochromic device according to an example of the present invention is bent and then unfolded to restore its original shape.

Fig. 8 shows a test in which an electrochromic device according to an example of the present invention is continued in a bent state for a prescribed time.

Fig. 9 illustrates a memory test in which an electrochromic device according to an example of the invention is powered off and held for a specified time.

Fig. 10 shows a top view of a test strip used for testing an electrochromic device according to an example of the present invention and light transmittance measurement points.

Description of reference numerals

A-A': cutting line, 10: a window is arranged on the base plate, and the window,

100: electrochromic device, 110: a first base layer for forming a first layer,

111: 1A primer layer, 112: the first primer layer of the second primer layer of the first primer layer of the second primer layer of the first primer layer of the second primer layer of the first primer layer of the second primer layer of the second first primer layer of the second primer layer of the second primer layer of the second primer layer of the second,

120: first barrier layer, 121: a barrier layer of a1 st layer of a silicon-containing material,

122: barrier layer 1B, 123: a first barrier layer of a first conductivity type having a first conductivity type,

130: light transmittance variable structure, 131: a first electrode layer formed on the first electrode layer,

133: first color changing layer, 135: the electrolyte layer is formed on the surface of the substrate,

137: second color changing layer, 139: a second electrode layer formed on the first electrode layer,

140: second barrier layer, 141: a barrier layer of a second layer having a first layer,

142: barrier layer 2B, 143: a second barrier layer (2C) having a second barrier layer,

150: second base layer, 151: a layer of the primer of the 2 nd a,

152: 2B primer layer, 160: a release film layer is arranged on the surface of the substrate,

161: adhesive layer, 170: a hard coating layer is coated on the surface of the substrate,

l: length of electrochromic device, D: the distance between the two ends of the electrochromic device.

Detailed Description

Hereinafter, examples of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art to which the present invention pertains can easily carry out the present invention. However, the examples may be implemented in various different forms and are not limited to the examples described in this specification.

When each film, window, panel, structure, layer, or the like is described in the present specification as being formed on "upper" or "lower" of each film, window, panel, structure, layer, or the like, "upper" and "lower" include all cases of "direct" or "indirect" formation.

The reference of the upper/lower direction of each component is based on the drawing. The size of each structural element in the drawings may be exaggerated for convenience of explanation and does not mean a size for practical use. In addition, like reference numerals denote like structural elements throughout the specification.

In the present specification, when some portions "include" some structural elements, the presence of other structural elements is not excluded unless otherwise stated, but it means that other structural elements may be further included.

In this specification, unless otherwise specified, singular expressions are to be construed as including the singular or plural meanings explained in the context.

Also, unless otherwise noted, all numbers and expressions referring to amounts of components, reaction conditions, and the like recited in the specification are to be understood as modified in all instances by the term "about".

In the present specification, terms such as first, second, and the like are used to describe various structural elements, and the above structural elements should not be limited by the above terms. The above terms are used to distinguish one structural element from another.

Electrochromic device

Embodiments of the present invention provide an electrochromic device that achieves excellent light transmittance adjustment performance based on the electrochromic principle while having flexibility.

An electrochromic device according to an example of the present invention includes a first substrate layer, a second substrate layer, and a light transmittance variable structure interposed therebetween.

The light transmittance variable structure includes a first color changing layer capable of adjusting coloring and color fading by applying a power source.

The light transmittance variable structure may further include: a first electrode layer formed under the first color changing layer; an electrolyte layer formed on the first color changing layer; a second color changing layer formed on the electrolyte layer; and a second electrode layer formed on the second color-changing layer, wherein the first color-changing layer may include a reductive color-changing substance and a polymer resin, and the second color-changing layer may include an oxidative color-changing substance and a polymer resin.

In the electrochromic device 100 according to an example of the present invention, the light transmittance variable structure 130 is interposed between the first substrate layer 110 and the second substrate layer 150, and the light transmittance variable structure 130 includes the first color-changing layer 133 and the second color-changing layer 137 (see fig. 3 and 4).

In the electrochromic device 100 according to an embodiment of the present invention, the light transmittance variable structure 130 is interposed between the first substrate layer 110 and the second substrate layer 150, the light transmittance variable structure 130 includes a first coloring layer 133 and a second coloring layer 137, and the electrolyte layer 135 is interposed between the first coloring layer 133 and the second coloring layer 137 (see fig. 3 and 4).

The electrochromic device 100 described above may be a flexible electrochromic device. And the above electrochromic device may have a thin sheet or film shape. The thickness of the electrochromic device 100 described above may be 20 μm to 1000 μm. Specifically, the thickness of the above electrochromic device 100 may be 25 μm to 900 μm, 25 μm to 800 μm, 25 μm to 700 μm, 25 μm to 600 μm, or 25 μm to 500 μm, but is not limited thereto.

The visible light average transmittance of the above electrochromic device in a maximum discolored state may be 40% to 90%, 50% to 90%, or 60% to 80%, but is not limited thereto. Also, the visible light average transmittance of the above electrochromic device in the maximum coloring state may be 10% to 40%, 10% to 30%, or 10% to 20%, but is not limited thereto.

The above electrochromic device can adjust not only the transmittance of visible rays but also the transmittance of infrared rays (IR rays) and ultraviolet rays (UV rays) upon coloring and discoloring.

A plurality of features of the structural composition, physical properties, and the like of each layer of the above electrochromic device may be combined with each other.

Flexible characteristics of electrochromic devices

The electrochromic device according to the above example realizes an excellent transmittance variable function based on the electrochromic principle while having a soft characteristic. In particular, the electrochromic device according to the above example can continue to maintain the light transmittance operation function with almost no change in light transmittance compared to the initial state even in the case of repeated bending or long-term maintenance of the bent state or long-term power off. For example, when the above electrochromic device is bent in a tensile (stretching) or compressive (compressive) direction with reference to the first color changing layer or the second color changing layer, the color changing function may be maintained.

In the electrochromic device 100 according to the above example, Δ TTd defined in the following formula (1)₂₄The value is 3% or less.

△TTd₂₄(％)＝│TTd₂₄－TTd₀│...(1)

In the above formula (1), TTd₀Average transmittance (%) of visible light, TTd in maximum discolored state when power is applied after deformation such that the above electrochromic device has a radius of curvature of 17R₂₄In order to measure the above TTd₀Then, the power was turned off, and the above electrochromic device was deformed into a state having a curvature radius of 17R and maintained for 24 hours, and then the visible light average transmittance (%) was measured.

Specifically, in the above electrochromic device 100, Δ TTd defined in the above formula (1)₂₄The value may be 2.5% or less, 2.0% or less, 1.8% or less, 1.5% or less, 0% to 3%, 0% to 2.5%, 0.1% to 2.0%, 0.2% to 1.5%, or 0.5% to 1.5%, but is not limited thereto.

In the present specification, the "maximum discolored state" refers to a state in which a voltage is applied to the electrochromic device to have the highest transmittance, and specifically, refers to a state in which a change of less than 1% during 20 seconds under visible light transmittance lasts for one minute or more when a power supply is applied to the electrochromic device to perform a discoloring operation.

Also, "the maximum coloring state" refers to a state in which a voltage is applied to the electrochromic device so as to have the lowest light transmittance, and specifically, refers to a state in which a change of less than 1% during 20 seconds under visible light transmittance lasts for one minute or more when a coloring operation is performed by applying a power source to the electrochromic device.

In the present specification, "transmittance" refers to visible light transmittance, specifically to visible light average transmittance. More specifically, the above-mentioned visible light average transmittance is based on an average value of a plurality of values measured at 5nm intervals in a wavelength range of 380nm to 780nm using an Ultraviolet spectrum (Ultraviolet spectrum) of JASCO corporation.

Further, in the above electrochromic device 100, Δ TTd defined in the following formula (4)₁₂The value may be 1% or less.

△TTd₁₂(％)＝│TTd₁₂－TTd₀│...(4)

In the above formula (4), TTd₀Average transmittance (%) of visible light, TTd in maximum discolored state when power is applied after deformation such that the above electrochromic device has a radius of curvature of 17R₁₂In order to measure the above TTd₀Then, the power was turned off, and the above electrochromic device was deformed into a state having a curvature radius of 17R and held for 12 hours, and then the visible light average transmittance (%) was measured.

Specifically, in the above electrochromic device 100, Δ TTd defined in the above formula (4)₁₂Values may be, but are not limited to, 0.8% or less, 0.7% or less, 0.6% or less, 0.5% or less, 0% to 1%, 0% to 0.8%, 0% to 0.7%, 0.1% to 0.6%, or 0.1% to 0.5%.

In the above electrochromic device, when Δ TTd is defined in the above formula (1)₂₄Value and Δ TTd defined in the above formula (4)₁₂When the value satisfies the above range, an electrochromic device exhibiting transmittance properties required for the performance at a prescribed level or higher even after the power is turned off can be realized.

If Δ TTd is defined in the above formula (1)₂₄A value or Δ TTd defined in the above formula (4)₁₂Values exceeding the above range mean the discoloration-retaining propertyAnd the maintenance performance, particularly in a colored state, is reduced, and the transmittance of the electrochromic device does not exhibit the desired level of performance when the power is turned off, and thus there is a problem in that it is not suitable for commercialization as a smart window.

When power is applied after the electrochromic device 100 described above is deformed so as to have a radius of curvature of 17R, the visible light average transmittance (%) at the maximum discolored state (TTd)₀) Is more than 60 percent. Specifically, the above TTd₀The value is 65% or more, 66% or more, or 67% or more.

TTd of the above electrochromic device₀When the value satisfies the range, the visible light transmittance in a wide range can be ensured, and the realization of the user-customized smart window is facilitated.

Further, in the above electrochromic device 100, Δ TTc defined in the following formula (2)₂₄The value may be 2% or less.

△TTc₂₄(％)＝│TTc₂₄－TTc₀│...(2)

In the above formula (2), TTc₀Average transmittance (%) of visible light in the maximum coloring state, TTc, when power is applied after being deformed such that the above electrochromic device has a radius of curvature of 17R₂₄In order to measure the above TTc₀Then, the power was turned off, and the above electrochromic device was deformed into a state having a curvature radius of 17R and maintained for 24 hours, and then the visible light average transmittance (%) was measured.

Specifically, in the above electrochromic device 100, Δ TTc defined in the above formula (2)₂₄The value may be 1.8% or less, 1.5% or less, 1.2% or less, 1.1% or less, 0% to 2%, 0% to 1.8%, 0% to 1.5%, 0.1% to 1.5%, 0.3% to 1.2%, or 0.4% to 1.1%, but is not limited thereto.

Further, in the above electrochromic device 100, Δ TTc defined in the following formula (5)₁₂The value may be 0.8% or less.

△TTc₁₂(％)＝│TTc₁₂－TTc₀│...(5)

In the above formula (5), TTc₀Is a warpAverage transmittance (%) of visible light in the maximum coloring state, TTc, when power is applied after the above electrochromic device has a curvature radius of 17R due to excessive deformation₁₂In order to measure the above TTc₀Then, the power was turned off, and the above electrochromic device was deformed into a state having a curvature radius of 17R and held for 12 hours, and then the visible light average transmittance (%) was measured.

Specifically, in the above electrochromic device 100, Δ TTc defined in the above formula (5)₁₂Values may be, but are not limited to, 0.7% or less, 0.6% or less, 0.5% or less, 0% to 0.8%, 0% to 0.7%, 0% to 0.6%, 0.1% to 0.6%, or 0.2% to 0.5%.

In the above electrochromic device, Δ TTc when defined in the above formula (2)₂₄The value and Δ TTc defined in the above formula (5)₁₂When the value satisfies the above range, an electrochromic device exhibiting transmittance properties required for the performance at a prescribed level or higher even after the power is turned off can be realized.

If Δ TTc defined in the above formula (2)₂₄A value or Δ TTc defined in the above formula (5)₁₂Values exceeding the above range mean that the color change retention property is lowered, particularly the retention property in a colored state is lowered, and the light transmittance of the electrochromic device does not exhibit a desired level of performance when the power is turned off, and thus there is a problem that it is not suitable for commercialization as a smart window.

When power is applied after the electrochromic device 100 described above is deformed so as to have a radius of curvature of 17R, the average transmittance (%) of visible light in the maximum colored state (TTc)₀) Is 20% or less. Specifically, TTc as described above₀The value is 17% or less, 15% or less, or 14% or less.

When the electrochromic device is TTc₀When the value satisfies the range, the color change interval which becomes transparent and dark is widened, so that the visible light transmittance in a wide range can be ensured, and the realization of the user-customized smart window is facilitated.

And, the electrochromic device has excellent blocking performance to visible light, UV rays and IR rays, so that light and heat entering from the outside can be easily adjusted, thereby controlling indoor brightness, blocking ultraviolet rays and saving indoor cooling/heating energy.

In the above electrochromic device 100, the TTRdc value defined in the following formula (3) is 90% or more.

TTRdc(％)＝(△TTdc₂₄/△TTdc₀)×100...(2)

In the above formula (3), Δ TTdc₀Shows the difference (%) between the average transmittance of visible light in the maximum discolored state and the average transmittance of visible light in the maximum colored state, and the Δ TTdc when a power supply is applied after the above electrochromic device is deformed so as to have a radius of curvature of 17R₂₄Is shown in the measurement of the above-mentioned Δ TTdc₀After that, when the power was turned off and the above electrochromic device was deformed into a state having a radius of curvature of 17R and held for 24 hours, the difference (%) between the average transmittance of visible light in the maximum discolored state and the average transmittance of visible light in the maximum colored state was observed.

Specifically, in the electrochromic device 100 described above, the TTRdc value defined in the above formula (3) may be 92% or more, 95% or more, 97% or more, 98% or more, 99% or more, 99.3% or more, or 99.4% or more, but is not limited thereto.

In the above electrochromic device, when the TTRdc value defined in the above formula (3) satisfies the above range, excellent transmittance variable property can be achieved even after deformation into a state having a small radius of curvature continues for several hours. Therefore, not only easy storage and transportation but also use without degrading performance after construction can be achieved by maintaining in a wound manner.

The above electrochromic device 100 did not generate cracks (cracks) in a state of being deformed to have a curvature radius of 70R. Specifically, the electrochromic device 100 described above does not develop cracks in a state of being deformed to have a radius of curvature of 70R or less. For example, the electrochromic device 100 does not generate cracks in a state of being deformed to have a radius of curvature of 30R or a radius of curvature of 17R.

Bending characteristics of electrochromic devices

Also, as shown in fig. 7, when the above electrochromic device repeatedly performs a test of bending and spreading both ends at a distance D corresponding to 25% of the length L in the lateral direction, a change in light transmittance may hardly occur. Also, as shown in fig. 8, when the electrochromic device is bent at both ends by a distance D corresponding to 25% of the length L in the lateral direction and is maintained in this state for a long time, there may be a case where the change in light transmittance hardly occurs. Further, as shown in fig. 9, when the electrochromic device is kept in a state of being powered off for a long time, there is a possibility that the change of the light transmittance hardly occurs.

According to one example, the electrochromic device has a first light transmittance change (Δ TT _ B30) defined in the following formula (i) of 1.5% or less when a bending test is repeated in which a test piece of the electrochromic device having a size of 300mm in width and 200mm in length is bent to make a distance between both lateral ends 75mm and then developed to restore the original shape.

△TT_B30(％)＝│TT_B30－TT_0│...(i)

In the above formula (i), TT _ B30 is the average transmittance (%) of visible light of the above electrochromic device measured in the maximum discolored state after repeating the above bending test 30 times, and TT _0 is the average transmittance (%) of visible light of the above electrochromic device measured in the maximum discolored state before the above bending test.

More specifically, the first light transmittance change (Δ TT _ B30) may be 1% or less, 0.5% or less, or 0.3% or less.

In the formula (i), the values of TT _ B30 and TT _0 may be 50% or more, 60% or more, or 65% or more, respectively, and may be 90% or less, 80% or less, or 70% or less, respectively. Specifically, in the above formula (i), the values of TT _ B30 and TT _0 may be 50% to 90%, 60% to 80%, or 65% to 70%, respectively.

Further, when the above bending test is repeated, the second light transmittance change (Δ TT _ B30_ d) defined in the following formula (ii) may be 3% or less.

△TT_B30_d(％)＝││TT_B30－TT_B30'│－│TT_0－TT_0'││...(ii)

In the formula (ii), TT _ B30 is the average transmittance (%) of visible light of the electrochromic device measured in the maximum discolored state after 30 times of the above-mentioned bending test, TT _ B30 'is the average transmittance (%) of visible light of the electrochromic device measured in the maximum colored state after 30 times of the above-mentioned bending test, TT _0 is the average transmittance (%) of visible light of the electrochromic device measured in the maximum discolored state before the above-mentioned bending test, and TT _0' is the average transmittance (%) of visible light of the electrochromic device measured in the maximum colored state before the above-mentioned bending test.

More specifically, the second transmittance change (Δ TT _ B30_ d) may be 2% or less, 1% or less, 0.5% or less, or 0.3% or less.

In the formula (ii), the values of TT _ B30 and TT _0 may be 50% or more, 60% or more, or 65% or more, respectively, and may be 90% or less, 80% or less, or 70% or less, respectively. Specifically, in formula (ii) above, TT _ B30 and TT _0 may have values of 50% to 90%, 60% to 80%, or 65% to 70%, respectively.

In the formula (ii), values of TT _ B30 'and TT _0' may be 30% or less, 20% or less, or 15% or less, respectively, and may be 0% or more, 5% or more, or 10% or more, respectively. Specifically, in formula (ii) above, TT _ B30 'and TT _0' may have values of 0% to 30%, 5% to 10%, or 10% to 15%, respectively.

Further, the electrochromic device may have a third transmittance change (Δ TT _ B50) defined in the following formula (iii) of 3% or less when the above bending test is repeated.

△TT_B50(％)＝│TT_B50－TT_0│...(iii)

In the above formula (iii), TT _ B50 is the average transmittance (%) of visible light of the above electrochromic device measured in the maximum discolored state after repeating the above bending test 50 times, and TT _0 is the average transmittance (%) of visible light of the above electrochromic device measured in the maximum discolored state before the above bending test.

More specifically, the third light transmittance change (Δ TT _ B50) may be 2% or less, 1% or less, 0.5% or less, or 0.3% or less.

In formula (iii), values of TT _ B50 and TT _0 may be 50% or more, 60% or more, or 65% or more, respectively, and may be 90% or less, 80% or less, or 70% or less, respectively. Specifically, in formula (iii) above, TT _ B50 and TT _0 may have values of 50% to 90%, 60% to 80%, or 65% to 70%, respectively.

In the electrochromic device, when a test piece of the electrochromic device having a size of 300mm in width and 200mm in length is used as a reference and the test piece is bent so that the distance between both ends in the lateral direction is 75mm and the test piece is continued for a predetermined time, the fourth light transmittance change (Δ TT — 100H) defined in the following formula (iv) may be 3% or less.

△TT_100H(％)＝│TT_100H－TT_0│...(iv)

In the above formula (iv), TT — 100H is the visible light average transmittance (%) of the above electrochromic device measured in the maximum discolored state after the above test was continuously performed for 100 hours, and TT — 0 is the visible light average transmittance (%) of the above electrochromic device measured in the maximum discolored state before the above test was continuously performed.

More specifically, the fourth transmittance change (Δ TT — 100H) may be 2% or less, 1% or less, 0.5% or less, or 0.3% or less.

In the formula (iv), the values of TT — 100H and TT — 0 may be 50% or more, 60% or more, or 65% or more, respectively, and may be 90% or less, 80% or less, or 70% or less, respectively. Specifically, in the above formula (iv), TT — 100H and TT — 0 may have values of 50% to 90%, 60% to 80%, or 65% to 70%, respectively.

In the electrochromic device, when the bending test is repeated after the test is continuously performed, the fifth transmittance change (Δ TT — 100H — B30) defined in the following formula (v) may be 3% or less.

△TT_100H_B30(％)＝│TT_100H_B30－TT_0│...(v)

In the above formula (v), TT — 100H _ B30 is the visible light average transmittance (%) of the electrochromic device measured in the maximum discolored state after repeating the above bending test 30 times after continuing the above test for 100 hours, and TT — 0 is the visible light average transmittance (%) of the electrochromic device measured in the maximum discolored state before continuing the above test.

More specifically, the fifth transmittance change (Δ TT — 100H _ B30) may be 2% or less, 1% or less, 0.5% or less, or 0.3% or less.

In the formula (v), the values of TT — 100H _ B30 and TT — 0 may be 50% or more, 60% or more, or 65% or more, respectively, and may be 90% or less, 80% or less, or 70% or less, respectively. Specifically, in the above formula (v), TT — 100H _ B30 and TT — 0 may have values of 50% to 90%, 60% to 80%, or 65% to 70%, respectively.

Further, in a memory test in which the power is applied to the electrochromic device after the bending test is repeated to reach the maximum discolored state and the electrochromic device is kept powered off for a predetermined time, the sixth transmittance change (Δ TT _ B30_ M12H) defined by the following formula (vi) of the electrochromic device may be 3% or less.

△TT_B30_M12H(％)＝│TT_B30_M12H－TT_0│...(vi)

In the formula (vi), TT _ B30_ M12H is the average transmittance (%) of visible light of the electrochromic device measured after the above memory test was performed for 12 hours in the maximum fading state after the above bending test was repeated 30 times, and TT _0 is the average transmittance (%) of visible light of the electrochromic device measured in the maximum fading state before the above bending test was performed.

More specifically, the sixth transmittance change (Δ TT _ B30_ M12H) may be 2% or less, 1% or less, 0.5% or less, or 0.3% or less.

In the formula (vi), the values of TT _ B30_ M12H and TT _0 may be 50% or more, 60% or more, or 65% or more, respectively, and may be 90% or less, 80% or less, or 70% or less, respectively. Specifically, in the above formula (vi), the values of TT _ B30_ M12H and TT _0 may be 50% to 90%, 60% to 80%, or 65% to 70%, respectively.

The visible light average transmittance referred to in the above formulas (i) to (vi) and the like means an average value of transmittance in a visible light wavelength range, and specifically may be an average value of a plurality of transmittances measured at 5nm intervals in a wavelength range of 380 to 780 nm.

Base layer

The first base layer 110 and the second base layer 150 correspond to layers for maintaining transparency and durability, and may include a polymer resin. For example, the first base layer and the second base layer may be polymer films.

Specifically, the first base layer and the second base layer may include one or more selected from the group consisting of: polyethylene terephthalate (PET), polyethylene naphthalate (PEN), Polycarbonate (PC), Polyimide (PI), poly 1, 4-cyclohexanedimethanol terephthalate (PCT), Polyethersulfone (PES), nylon (nylon), Polymethylmethacrylate (PMMA), and Cyclic Olefin Polymer (COP), but not limited thereto. More specifically, the first substrate layer and the second substrate layer may each include polyethylene terephthalate (PET).

Since the first underlayer and the second underlayer contain the polymer resin, an electrochromic device having durability and flexibility can be realized.

The first and second base layers may have a transmittance of 80% or more with respect to light having a wavelength of 630 nm. Specifically, the first and second base layers may have transmittances of 85% or more or 90% or more, respectively, with respect to light having a wavelength of 630 nm. The first underlayer and the second underlayer may each have a transmittance of 80% or more with respect to light having a wavelength of 550 nm. Specifically, the first and second base layers may have transmittances of 85% or more or 90% or more, respectively, with respect to light having a wavelength of 550 nm.

The first substrate layer and the second substrate layer may have a haze of less than 2.0%, 1.8% or less, or 1.5% or less, respectively. The first base layer and the second base layer may each have an elongation of 80% or more. Specifically, the first base layer and the second base layer may have an elongation of 90% or more, 100% or more, or 120% or more, respectively. The first base layer and the second base layer can satisfy the transmittance and haze in the above ranges, respectively, and have transparency, and can satisfy the elongation in the above ranges, and have flexibility.

The thickness of the first base layer may be 10 μm to 300 μm. Specifically, the thickness of the above first base layer may be 10 μm to 250 μm, 10 μm to 200 μm, 20 μm to 250 μm, 20 μm to 200 μm, 25 μm to 188 μm, or 50 μm to 150 μm, but is not limited thereto.

The thickness of the second substrate layer may be 10 μm to 300 μm. Specifically, the thickness of the above-mentioned second base layer may be 10 μm to 250 μm, 10 μm to 200 μm, 20 μm to 250 μm, 20 μm to 200 μm, 25 μm to 188 μm, or 50 μm to 150 μm, but is not limited thereto. Also, the thickness of the first base layer and the thickness of the second base layer may be 50 μm to 180 μm, 70 μm to 180 μm, 80 μm to 180 μm, 100 μm to 170 μm, or 100 μm to 150 μm, respectively, but is not limited thereto. When the thickness of the first substrate layer and the thickness of the second substrate layer satisfy the above ranges, the elongation and tensile strength of the electrochromic device can be achieved at a specific level. Further, when the electrochromic device is bent, cracks or cracks do not occur in each layer, and a thin, light and flexible electrochromic device can be realized, which is also advantageous for making a thin film.

Barrier layer

The barrier layer is used to prevent impurities including moisture or gas from penetrating into the light transmittance variable structure from the outside, and may include, for example, a first barrier layer and a second barrier layer.

As shown in fig. 3, the electrochromic device 100 described above may include: a first substrate layer 110; a first barrier layer 120 formed on the first base layer 110; a variable light transmittance structure 130 formed on the first barrier layer 120; a second barrier layer 140 formed on the light transmittance variable structure 130; and a second base layer 150 formed on the second barrier layer 140.

The first barrier layer 120 and the second barrier layer 140 may include two or more layers, respectively. Specifically, the first barrier layer 120 and the second barrier layer 140 may include two layers or three layers, respectively (see fig. 5).

In one example, the first barrier layer 120 may include two layers, and the second barrier layer 140 may include two layers.

In another example, the first barrier layer 120 may include three layers, and the second barrier layer 140 may include three layers.

The first barrier layer 120 may include a 1A barrier layer 121 and a 1B barrier layer 122, or the first barrier layer may include a 1A barrier layer 121, a 1B barrier layer 122, and a 1C barrier layer 123 (see fig. 5).

Specifically, the first barrier layer may have a structure in which a 1A-th barrier layer and a 1B-th barrier layer are sequentially stacked; or a structure in which the 1A th barrier layer, the 1B th barrier layer, and the 1C th barrier layer are stacked in this order.

The first barrier layer may be laminated on the first substrate layer.

The second barrier layer 140 may include a 2A barrier layer 141 and a 2B barrier layer 142, or the second barrier layer may include a 2A barrier layer 141, a 2B barrier layer 142, and a 2C barrier layer 143 (see fig. 5).

Specifically, the second barrier layer may have a structure in which a 2A-th barrier layer and a 2B-th barrier layer are sequentially stacked; or a structure in which a 2A barrier layer, a 2B barrier layer, and a 2C barrier layer are sequentially stacked may be used.

The second barrier layer may be laminated under the second substrate layer.

In one example, the first barrier layer 120 may include a 1A barrier layer 121 and a 1B barrier layer 122, and the second barrier layer 140 may include a 2A barrier layer 141 and a 2B barrier layer 142. Alternatively, the first barrier layer may include a 1A barrier layer 121, a 1B barrier layer 122, and a 1C barrier layer 123, and the second barrier layer 140 may include a 2A barrier layer 141 and a 2B barrier layer 142.

The first barrier layer 120 and the second barrier layer 140 respectively include one or more selected from the following: metal oxides, metal nitrides, metal oxynitrides, semimetal oxides, semimetal nitrides, semimetal oxynitrides, and combinations thereof.

Specifically, the first barrier layer 120 and the second barrier layer 140 respectively include one or more selected from the group consisting of: metal nitrides, metal oxynitrides, semimetal nitrides, semimetal oxynitrides, and combinations thereof.

More specifically, the first barrier layer 120 and the second barrier layer 140 respectively include a metal nitride or a semi-metal nitride.

In one example, the first barrier layer 120 may include a 1A barrier layer 121 and a 1B barrier layer 122, one of the 1A barrier layer and the 1B barrier layer may include a metal oxide or a semi-metal oxide, and the other may include a metal nitride or a semi-metal nitride.

The first barrier layer 120 may further include a 1C barrier layer 123. In this case, the 1C th barrier layer may include acrylic resin, epoxy resin, silicone resin, polyimide resin, or urethane resin.

The second barrier layer 140 may include a 2A barrier layer 141 and a 2B barrier layer 142, one of the 2A barrier layer and the 2B barrier layer may include a metal oxide or a semi-metal oxide, and the other may include a metal nitride or a semi-metal nitride.

The second barrier layer 140 may further include a 2C barrier layer 143. In this case, the 2C th barrier layer may include acrylic resin, epoxy resin, silicone resin, polyimide resin, or urethane resin.

In another example, the first barrier layer includes a 1A barrier layer and a 1B barrier layer, and a thickness ratio of the 1A barrier layer to the 1B barrier layer is 1: 2 to 1: 10. in this case, the 1A-th barrier layer includes a metal nitride or a semimetal nitride, and the 1B-th barrier layer includes a metal oxide or a semimetal oxide.

The thickness ratio of the 1A barrier layer to the 1B barrier layer may be 1: 2.5 to 1: 10 or 1: 2.5 to 1: 7.5, but not limited thereto.

When the thickness ratio of the 1A barrier layer to the 1B barrier layer satisfies the above range, long-term reliability such as optical characteristics, refractive index, and weather resistance of the film is improved. When the thickness ratio of the 1A-th barrier layer and the 1B-th barrier layer is out of the above range, the refractive index may be lowered, the layers may become opaque, or the long-term reliability of optical characteristics, weather resistance, and the like may be lowered.

The second barrier layer may include a 2A barrier layer and a 2B barrier layer, and a thickness ratio of the 2A barrier layer to the 2B barrier layer may be 1: 2 to 1: 10. in this case, the 2A barrier layer includes a metal nitride or a semimetal nitride, and the 2B barrier layer includes a metal oxide or a semimetal oxide.

The thickness ratio of the 2A barrier layer to the 2B barrier layer may be 1: 2.5 to 1: 10 or 1: 2.5 to 1: 7.5, but not limited thereto.

When the thickness ratio of the 1A barrier layer to the 1B barrier layer and the thickness ratio of the 2A barrier layer to the 2B barrier layer satisfy the above ranges, long-term reliability such as optical characteristics, refractive index, and weather resistance of the film is improved.

On the contrary, if the thickness ratio of the 1A barrier layer to the 1B barrier layer or the thickness ratio of the 2A barrier layer to the 2B barrier layer exceeds the above range, the refractive index may be lowered, the layer may become opaque, or the long-term reliability such as optical characteristics and weather resistance may be lowered.

In one example, the first barrier layer includes a 1A barrier layer and a 1B barrier layer, the first base layer, the 1A barrier layer and the 1B barrier layer are sequentially stacked, the 1A barrier layer includes a metal nitride or a semi-metal nitride, and the 1B barrier layer includes a metal oxide or a semi-metal oxide.

In another example, the first barrier layer includes a 1A barrier layer, a 1B barrier layer, and a 1C barrier layer, the first base layer, the 1A barrier layer, the 1B barrier layer, and the 1C barrier layer are sequentially stacked, the 1A barrier layer includes a metal nitride or a semi-metal nitride, the 1B barrier layer includes a metal oxide or a semi-metal oxide, and the 1C barrier layer includes an acrylic resin, an epoxy resin, a silicon resin, a polyimide resin, or a polyurethane resin.

In this case, the thickness of the 1A barrier layer may be 10nm to 50nm, 10nm to 40nm, or 10nm to 30nm, but is not limited thereto.

Also, the thickness of the 1B-th barrier layer may be 30nm to 100nm, 30nm to 80nm, 30nm to 70nm, or 40nm to 60nm, but is not limited thereto.

The moisture permeability of the 1A barrier layer and the 1B barrier layer may be 0.2g/day m²0.15g/day m as follows²The following or 0.1g/day m²The following is not limitative.

When the thickness ranges and the moisture permeability of the 1A th barrier layer and the 1B th barrier layer satisfy the above ranges, there is an effect that long-term reliability such as optical characteristics, refractive index, and weather resistance of the film is improved.

On the contrary, if it exceeds the above range, the refractive index may be lowered, or the opacity may be obtained, or the long-term reliability of the optical characteristics, weather resistance and the like may be lowered.

In one example, the second barrier layer includes a 2A barrier layer and a 2B barrier layer, the second substrate layer, the 2A barrier layer and the 2B barrier layer are sequentially stacked, the 2A barrier layer includes a metal nitride or a semi-metal nitride, and the 2B barrier layer includes a metal oxide or a semi-metal oxide.

The second barrier layer includes a 2A barrier layer, a 2B barrier layer, and a 2C barrier layer, the second underlying layer, the 2A barrier layer, the 2B barrier layer, and the 2C barrier layer are sequentially stacked, the 2A barrier layer includes a metal nitride or a semi-metal nitride, the 2B barrier layer includes a metal oxide or a semi-metal oxide, and the 2C barrier layer includes an acrylic resin, an epoxy resin, a silicone resin, a polyimide resin, or a polyurethane resin.

In this case, the thickness of the above-mentioned 2A barrier layer may be 10nm to 50nm, 10nm to 40nm, or 10nm to 30nm, but is not limited thereto.

Also, the thickness of the above-mentioned 2B barrier layer may be 30nm to 100nm, 30nm to 80nm, 30nm to 70nm, or 40nm to 60nm, but is not limited thereto.

The moisture permeability of the 2A barrier layer and the 2B barrier layer may be 0.2g/day m²0.15g/day m as follows²The following or 0.1g/day m²The following is not limitative.

When the thickness ranges and the moisture permeability of the 1A th barrier layer and the 1B th barrier layer satisfy the above ranges, long-term reliability such as optical characteristics, refractive index, weather resistance, and the like of the film is improved, and conversely, if the thickness ranges and the moisture permeability exceed the above ranges, the refractive index may be decreased, or the film may become opaque, or long-term reliability such as optical characteristics, weather resistance, and the like may be decreased.

The moisture permeability of the first barrier layer and the moisture permeability of the second barrier layer may be the same or different. Specifically, the moisture permeability of the first barrier layer and the moisture permeability of the second barrier layer may be different.

As a specific example, the first barrier layer includes a 1A barrier layer and a 1B barrier layer, the first substrate layer, the 1A barrier layer and the 1B barrier layer are sequentially stacked, the 1A barrier layer includes silicon nitride (SiNx), and the 1B barrier layer includes silicon oxide (SiOx). And, optionally, the first barrier layer may further include a 1C barrier layer including an acrylic resin.

When the 1A barrier layer contains silicon nitride, Si: the ratio of N may be 1.0: 0.8 to 1.0: 1.2, but not limited thereto. When the above 1B th barrier layer contains silicon oxide, Si: the ratio of O may be 1.0: 1.7 to 1.0: 2.3, but is not limited thereto.

The second barrier layer includes a 2A barrier layer and a 2B barrier layer, the second base layer, the 2A barrier layer, and the 2B barrier layer are sequentially stacked, the 2A barrier layer includes silicon nitride (SiNx), and the 2B barrier layer includes silicon oxide (SiOx). And, optionally, the second barrier layer may further include a 2C barrier layer including acrylic resin, epoxy resin, silicone resin, polyimide resin, or urethane resin.

When the 2A barrier layer contains silicon nitride, Si: the ratio of N may be 1.0: 0.8 to 1.0: 1.2, but not limited thereto. When the above-mentioned 2B th barrier layer contains silicon oxide, Si: the ratio of O may be 1.0: 1.7 to 1.0: 2.3, but is not limited thereto.

When the first barrier layer and the second barrier layer satisfy the above conditions, desired performance can be achieved even with a thin thickness, and durability and long-term stability of the electrochromic device can be improved by preventing moisture permeation as much as possible.

The first barrier layer and the second barrier layer may be vapor-deposited on the first base layer and the second base layer, respectively, by a vacuum vapor deposition method. Specifically, the first barrier layer and the second barrier layer may be deposited on the first underlying layer and the second underlying layer, respectively, by a sputtering deposition method.

In this case, the evaporation raw material may be one or more of a metal or a semimetal (metalloid), and the kind thereof is not particularly limited, and for example, may include at least one selected from magnesium (Mg), silicon (Si), indium (In), titanium (Ti), bismuth (Bi), germanium (Ge), and aluminum (Al).

The reaction gas for evaporation may include oxygen (O)₂) Or nitrogen (N)₂). When oxygen is used as the reaction gas, a barrier layer comprising a metal oxide or a semimetal oxide may be formed, and when nitrogen is used as the reaction gas, a barrier layer comprising a metal nitride or a semimetal nitride may be formedThe barrier layer of (1). When oxygen and nitrogen are appropriately mixed and used as the reaction gas, a barrier layer including a metal oxynitride or a semi-metal oxynitride can be formed.

The vacuum evaporation method includes a physical vacuum evaporation method and a chemical vacuum evaporation method. The physical vacuum deposition method includes thermal vacuum deposition, electron beam (E-beam) vacuum deposition, sputter deposition, and the like.

The sputtering may be direct current magnetron sputtering or alternating current magnetron sputtering.

Specifically, the dc magnetron sputtering may be plasma sputtering, for example, reactive plasma sputtering (reactive plasma sputtering).

Light transmittance variable structure

The light transmittance variable structure 130 includes: a first electrode layer 131; a first color changing layer 133 formed on the first electrode layer 131; an electrolyte layer 135 formed on the first discoloring layer 133; a second color changing layer 137 formed on the electrolyte layer 135; and a second electrode layer 139 formed on the second color changing layer 137 (see fig. 4).

The light transmittance variable structure 130 may be a structure in which a first electrode layer 131, a first color changing layer 133, an electrolyte layer 135, a second color changing layer 137, and a second electrode layer 139 are sequentially stacked. Specifically, the light transmittance variable structure is a laminated structure in which light transmittance reversibly changes when a predetermined voltage is applied.

Specifically, when a voltage is applied to the first electrode layer 131 and the second electrode layer 139, light transmittance as a whole is increased or decreased according to specific ions or electrons transmitted from the second coloration layer 137 to the first coloration layer 133 through the electrolyte layer 135.

When the light transmittance of the second color changing layer 137 is decreased, the light transmittance of the first color changing layer 133 is also decreased, and when the light transmittance of the second color changing layer 137 is increased, the light transmittance of the first color changing layer 133 is also increased.

A first electrode layer and a second electrode layer

The first electrode layer and the second electrode layer may include a transparent electrode or a reflective electrode, respectively. In one example, one of the first electrode layer and the second electrode layer may be a transparent electrode, and the other may be a reflective electrode. In another example, both the first electrode layer and the second electrode layer may be transparent electrodes.

The first electrode layer 131 may be formed on the first barrier layer 120 by evaporation using a sputtering method. The second electrode layer 139 may be formed on the second barrier layer 140 by evaporation using a sputtering method.

The transparent electrode may be made of a material having high light transmittance, low sheet resistance, and permeation resistance, and may be formed in an electrode plate shape.

For example, the transparent electrode may include one selected from the group consisting of: indium-tin oxide (ITO), zinc oxide (ZnO), indium-zinc oxide (IZO), and combinations thereof.

For example, the reflective electrode may include at least one selected from the group consisting of: silver (Ag), aluminum (Al), copper (Cu), molybdenum (Mo), gold (Au), tungsten (W), chromium (Cr), and combinations thereof.

The thicknesses of the first electrode layer 131 and the second electrode layer 139 may be, but are not limited to, 100nm to 500nm, 100nm to 400nm, 100nm to 300nm, or 150nm to 250nm, respectively.

The first electrode layer and the second electrode layer may be transparent electrodes, respectively, and may include indium-tin oxide.

Specifically, the first electrode layer and the second electrode layer may respectively include a material having a weight ratio of 70: 30 to 98: 2 or 80: 20 to 97: 3 indium oxide: tin oxide.

The surface resistances of the first electrode layer and the second electrode layer may be, but not limited to, 5 Ω/sq to 100 Ω/sq, 5 Ω/sq to 80 Ω/sq, 5 Ω/sq to 70 Ω/sq, or 5 Ω/sq to 50 Ω/sq.

A first color-changing layer

The first color changing layer 133 is a layer in which light transmittance changes when a voltage is applied between the first electrode layer 131 and the second electrode layer 139, and is a layer that provides light transmittance variability to the electrochromic device.

The first color-changing layer may contain a substance having a color-developing property complementary to that of the electrochromic substance contained in the second color-changing layer. The complementary color development characteristics mean that the reaction types of the color development of the electrochromic substances are different from each other.

For example, when an oxidative color-changing substance is used for the first color-changing layer, a reductive color-changing substance may be used for the second color-changing layer, and when a reductive color-changing substance is used for the first color-changing layer, an oxidative color-changing substance may be used for the second color-changing layer.

Specifically, the first color-changing layer 133 may contain a reductive color-changing substance, and the second color-changing layer 137 may contain an oxidative color-changing substance.

The oxidative coloring matter is a matter that changes color when undergoing an oxidation reaction, and the reductive coloring matter is a matter that changes color when undergoing a reduction reaction.

That is, when an oxidation reaction occurs in the color changing layer to which the oxidative color changing substance is applied, a coloring reaction occurs, and when a reduction reaction occurs, a color fading reaction occurs. In the color-changing layer using a reductive color-changing substance, a coloring reaction occurs when a reduction reaction occurs, and a color-fading reaction occurs when an oxidation reaction occurs.

As such, since each color-changing layer contains substances having complementary color-developing characteristics, coloring or color-changing can be simultaneously achieved in both layers. Also, coloring and discoloring may be alternately performed according to the polarity of voltage applied to the electrochromic device.

The first electrode layer 131 and the first color changing layer 133 may have an initial transmittance of 90% or more. Specifically, the above initial light transmittance satisfying the above range means that the above layers are very uniformly coated and are very transparent.

In one example, the first color-changing layer 133 may include a reductive color-changing substance and a polymer resin.

The reductive color-changing substance may beOne or more selected from the group consisting of: titanium oxide (TiO), vanadium oxide (V)₂O₅) Niobium oxide (Nb 2O)₅) Chromium oxide (Cr)₂O₃) Manganese oxide (MnO)₂) Iron oxide (FeO)₂) Cobalt oxide (CoO)₂) Nickel oxide (NiO)₂) Rhodium oxide (RhO)₂) Tantalum oxide (Ta)₂O₅) Iridium oxide (IrO)₂) Tungsten oxide (WO)₂，WO₃，W₂O₃，W₂O₅) Viologen (viologen), and combinations thereof, but is not limited thereto.

The polymer resin may be a flexible resin, and is not limited to a specific kind. For example, the polymer resin may be one or more selected from the group consisting of: silicone resins, acrylic resins, phenolic resins, polyurethane resins, polyimide resins, and ethylene-vinyl acetate resins, but are not limited thereto. For example, the first discoloring layer 133 may include tungsten oxide (WO)₃) And an acrylic resin.

The first color-changing layer 133 may include a reductive color-changing substance and a polymer resin, and may include 0.1 to 15 parts by weight of the polymer resin based on 100 parts by weight of the reductive color-changing substance. Specifically, the polymer resin may be included by 1 to 15 parts by weight, 2 to 15 parts by weight, or 3 to 10 parts by weight, based on 100 parts by weight of the above reductive color change substance. As a preferable example, the first color-changing layer may include 100 parts by weight of a reductive color-changing substance and 2 to 12 parts by weight of a polymer resin. As another preferable example, the first color-changing layer may include 100 parts by weight of a reductive color-changing substance and 3 to 7 parts by weight of a polymer resin. When within the above preferred range, it may be more advantageous to suppress a change in visible light transmittance that may occur after repeated bending of the electrochromic device, after a long-term retention of the bent state, or after a long-term power-off.

However, when the first color-changing layer contains a polymer resin exceeding the above range based on 100 parts by weight of the reductive color-changing substance, a specific level of light transmittance may not be maintained due to a decrease in storage performance, or a color-changing speed may be decreased due to an increase in a color-changing time required to achieve a specific light transmittance. When the first color-changing layer contains a polymer resin in an amount less than the above range based on 100 parts by weight of the reductive color-changing substance, cracks may be generated when the first color-changing layer is deformed to have a small radius of curvature due to a reduction in flexibility, and it is difficult to realize a light transmittance changing function of a predetermined level.

The first color-changing layer 133 may include at least one layer, and may include two or more layers having different materials, for example.

The first color-changing layer 133 may have a thickness of 100nm to 1000nm, 200nm to 800nm, 200nm to 700nm, 300nm to 700nm, or 300nm to 600 nm. When the thickness of the first color-changing layer satisfies the above range, the degree of change in transmittance of the above transmittance variable structure may impart significant transmittance variability to the entire electrochromic device, and thus, the entire electrochromic device may be applied to a building or a window, thereby realizing a transmittance change characteristic capable of achieving an energy adjustment effect. In particular, when the thickness of the first color-changing layer is within 300nm to 600nm, it may be more advantageous to suppress a change in visible light transmittance that may occur after repeated bending of the electrochromic device, after maintaining a bent state for a long time, or after turning off the power supply for a long time.

The thickness of the first color-changing layer and the content of the polymer resin may satisfy a certain relationship. As a specific example, the thickness of the first color-changing layer may be within ± 150nm, within ± 100nm, or within ± 50nm, based on the thickness calculated using the content of the polymer resin as a factor in the following formula.

First color change layer thickness (nm) ═ polymer resin content (parts by weight) × 75 (nm/parts by weight) +75(nm)

In the above formula, the content of the polymer resin is based on 100 parts by weight of the reductive color-changing substance in the first color-changing layer.

When the above preferable relationship is satisfied between the thickness of the first coloring layer and the content of the polymer resin, it may be more advantageous to suppress a change in visible light transmittance that may occur after repeated bending of the electrochromic device, after a long-term bent state is maintained, or after a long-term power off.

A second color-changing layer

The second color changing layer 137 is a layer in which light transmittance changes when a voltage is applied between the first electrode layer 131 and the second electrode layer 139, and is a layer that provides the electrochromic device with light transmittance variability.

In another example, the second color-changing layer 137 may include an oxidative color-changing substance and a polymer resin.

The oxidative coloring matter may be one or more selected from the group consisting of: nickel oxides (nickel oxides, e.g. NiO, NiO)₂) Manganese oxides (e.g. MnO)₂) Cobalt oxide (cobalt oxide, e.g., CoO)₂) Iridium-magnesium oxide (iridium-magnesium oxide), nickel-magnesium oxide (nickel-magnesium oxide), titanium-vanadium oxide (titanium-vanadium oxide), prussian blue dye, and combinations thereof, but is not limited thereto. The Prussian blue dye is a deep blue dye with a chemical formula of Fe₄(Fe(CN)₆)₃The compound of (1).

The polymer resin may be a flexible resin, and is not limited to a specific kind. For example, the polymer resin may be urethane-acrylic resin, silicone resin, acrylic resin, ester resin, epoxy resin, phenol resin, urethane resin, polyimide resin, ethylene-vinyl acetate resin, or the like, but is not limited thereto.

The polymer resin may have a weight average molecular weight of 50 to 10000. Specifically, the weight average molecular weight of the above polymer resin may be 100 to 10000, 200 to 10000, or 500 to 10000, but is not limited thereto.

For example, the second color-changing layer 137 may include nickel oxide (NiO) and an acrylic resin, and the weight average molecular weight of the acrylic resin may be 50 to 10000.

The second color changing layer 137 may include an oxidative color changing substance and a polymer resin, and may include 0.1 to 5 parts by weight of the polymer resin based on 100 parts by weight of the oxidative color changing substance.

When the second color-changing layer contains the polymer resin in the above range based on 100 parts by weight of the oxidative color-changing substance, the oxidative color-changing substance is stably attached to the film surface, thereby contributing to flexible transmittance-changing performance.

On the other hand, when the polymer resin is less than the above range, the oxidative coloring matter is weakly adhered to the film surface, and there is a problem of peeling or scattering even under a slight external impact, and the flexibility is weakened, so that color cracks may be generated at the time of bending. Further, when the polymer resin exceeds the above range, the ionic conductivity of the oxidative coloring matter may be lowered due to the resistance ion of the polymer resin itself, and the ionic conductivity performance of the oxidative coloring matter may be lowered, and the durability at high temperature may be weakened, resulting in the lowering of reliability.

The second color changing layer 137 includes at least one layer, and may be applied to two or more layers having different materials according to need.

The thickness of the second color-changing layer 137 may be, but is not limited to, 100nm to 1000nm, 100nm to 800nm, 100nm to 600nm, 100nm to 500nm, 100nm to 400nm, 200nm to 800nm, or 300nm to 800 nm.

When the thickness of the second color changing layer 137 satisfies the above range, it can well endure external impact and retain a proper amount of ions, and at the same time, it is advantageous to realize the thinning of the electrochromic device, ensure flexibility, and realize excellent transmittance change characteristics.

In contrast, when the thickness of the above-mentioned second color-changing layer is less than the above-mentioned range, the property of ionic conductivity is degraded due to the thinner color-changing layer, so that it may be difficult to appropriately achieve color-changing properties. Also, when exceeding the above range, since the discoloration layer is thick, cracks are generated even under a slight external impact, and thus it may be difficult to implement as a flexible electrochromic device, and the manufacturing cost is increased, and thus may be uneconomical.

The initial transmittance of the second color-changing layer 137 may be 50% or less. Specifically, the above-mentioned initial light transmittance satisfying the above-mentioned range means a dark deep blue color or a light blue color when observed with naked eyes.

In an example, the first color changing layer 133 may include a reductive color changing material, the second color changing layer 137 may include an oxidative color changing material, and the first color changing layer and the second color changing layer may be formed by wet coating (wet coating).

Specifically, the first color-changing layer 133 may be formed by applying a raw material to one surface of the first electrode layer 131 by a wet coating method and then drying the applied raw material. The second color changing layer 137 may be formed by applying a raw material to one surface of the second electrode layer 139 by a wet coating method and then drying the applied raw material.

The solvent used in the wet coating may be a non-aromatic solvent or an aromatic solvent, and specifically, ethanol, acetone, toluene, or the like, but is not limited thereto.

If the first color-changing layer and the second color-changing layer are formed by a sputter coating method, the application to an electrochromic device having excellent light transmittance variability performance and flexibility is limited because only a very thin coating film of 100nm or less is formed due to the characteristics of the coating method.

The ratio of the thicknesses of the first color-changing layer and the second color-changing layer may be 50: 50 to 80: 20. 55: 45 to 75: 25 or 60: 40 to 70: 30.

when the thickness ratio of the first color-changing layer to the second color-changing layer satisfies the above range, the color change interval of the transparent and dark color becomes wider and the color change time becomes shorter. In contrast, if the above range is not satisfied, the transparent and dark color change interval may be very narrow and the color change time may increase so that the change is very slow, or may not work even if the electrochromic device is powered on.

Electrolyte layer

The electrolyte layer 135 is a layer serving as an ion transmission path between the first discoloring layer and the second discoloring layer, and the kind of electrolyte used for the electrolyte layer is not particularly limited.

For example, the electrolyte layer may contain hydrogen ions or group 1 element ions. Specifically, the electrolyte layer may include a lithium salt compound. The lithium salt compound may be LiClO₄、LiBF₄、LiAsF₆、LiPF₆LiTFSI, LiFSI, etc., but not limited thereto.

The electrolyte layer may contain a polymer resin. Specifically, the electrolyte layer may include, but is not limited to, acrylic resin, epoxy resin, silicone resin, polyimide resin, or urethane resin.

Specifically, the acrylic resin may be a thermosetting acrylic resin, a photocurable acrylic resin, or the like, and the urethane resin may be a thermosetting urethane resin, a photocurable urethane resin, an aqueous urethane resin, or the like.

The electrolyte layer may include 95: 5 to 80: 20. 95: 5 to 85: 15 or 93: 7 to 87: 3 and a lithium salt.

The ion conductivity of the electrolyte layer may be 10^-3mS/cm or more. Specifically, the ion conductivity of the electrolyte layer may be 10^-3mS/cm to 10³mS/cm or 10^-3mS/cm to 10²mS/cm. When the ionic conductivity of the above electrolyte layer is within the above range, a desired light transmittance variable property can be achieved, and it is also advantageous in terms of flexibility and reliability at high temperatures. The ion conductivity of the electrolyte layer may be 30. mu.S/cm or more, 40. mu.S/cm or more, 50. mu.S/cm or more, 60. mu.S/cm or more, or 80. mu.S/cm or more, but is not limited thereto.

The adhesive strength of the electrolyte layer may be 200g/inch or more. Specifically, the adhesive force of the electrolyte layer may be 200g/inch to 900g/inch, 200g/inch to 700g/inch, 300g/inch to 900g/inch, or 450g/inch to 650g/inch, but is not limited thereto. When the adhesive force of the electrolyte layer is within the above range, it is well adhered to the substrates on both sides, so that the performance of the electrochromic device is flexibly expressed.

The electrolyte layer 135 may be formed by applying a raw material to one surface of either the first coloring layer 133 or the second coloring layer 137 by a wet coating method and then drying the applied raw material.

When the above electrolyte layer is applied by a wet coating method, the thickness of the coating film can be increased or easily controlled, thereby facilitating an increase in ionic conductivity or an increase in the rate of discoloration. In contrast, in the case of using a sputtering coating method instead of a wet coating method for the above electrolyte layer, since the coating film forms a thin film, the coating film is easily broken or the ionic conductivity is decreased.

The thickness of the electrolyte layer 135 may be 30 μm to 200 μm, 50 μm to 150 μm, 70 μm to 130 μm, or 80 μm to 120 μm. When the thickness of the above electrolyte layer 135 satisfies the above range, it is possible to realize a light transmittance change performance at an appropriate speed by imparting durability to the electrochromic device while securing a transmission path of ions between the first coloring layer and the second coloring layer with an appropriate length.

Release film layer

The flexible electrochromic device 100 according to an example may further include a release film layer 160 on a surface of the first substrate layer 110 opposite to a surface on which the first barrier layer 120 is laminated (see fig. 6).

The release film layer 160 may include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), or a polyester resin including Polycarbonate (PC).

Specifically, the thickness of the above release film layer may be 10 μm to 100 μm, 10 μm to 80 μm, 10 μm to 50 μm, or 12 μm to 50 μm, but is not limited thereto.

The release film layer has a peel force of 50gf/inch or less. Specifically, the release film layer may have a peel force of 3gf/inch to 50gf/inch or 10gf/inch to 50gf/inch, but is not limited thereto.

The release film layer has a function of protecting the electrochromic device from external moisture or impurities when the electrochromic device is stored and transferred, and the electrochromic device can be used after the release film layer is removed as required when the electrochromic device is subsequently applied to a transparent window or the like. In particular, the release film layer can prevent the adhesive force of the adhesive layer from being reduced.

An adhesive layer 161 may be formed on one side of the release film layer.

The adhesive layer 161 may include acrylic resin, silicone resin, urethane resin, epoxy resin, or polyimide resin. Specifically, the adhesive layer may contain an acrylic resin, and in this case, it is advantageous to improve optical characteristics and durability.

The UV blocking ratio (400nm basis) of the adhesive layer may be 95% or more, 97% or more, 98% or more, or 99% or more, but is not limited thereto.

Also, the initial adhesive force of the above adhesive layer may be 0.5N/inch to 8.0N/inch, 1.0N/inch to 7.0N/inch, or 2.0N/inch to 6.0N/inch, but is not limited thereto.

Primer layer

The primer layer may be laminated on one or both sides of the first substrate layer 110. Specifically, the 1A primer layer 111 may be laminated on one surface of the first base layer 110, and the 1B primer layer 112 may be laminated on the other surface of the first base layer 110 (see fig. 6).

The primer layer may be laminated on one or both surfaces of the second base layer 150. Specifically, the 2A primer layer 151 may be laminated on one surface of the second base layer 150, and the 2B primer layer 152 may be laminated on the other surface of the second base layer 150 (see fig. 6).

In one example, a primer layer may be interposed between the first barrier layer 120 and the first substrate layer 110. The primer layer may be interposed between the second barrier layer 140 and the second base layer 150 (see fig. 6).

The above-described primer layers (1A primer layer, 1B primer layer, 2A primer layer, 2B primer layer) may respectively include acrylic resin, polyurethane resin, silicone resin, or polyimide resin.

The above primer layers (1A primer layer, 1B primer layer, 2A primer layer, 2B primer layer) may have 35dyne/cm, respectively²Surface tension of the following or 30dyne/cm²The following surface tensions.

The above primer layer (1A primer layer, 1B primer layer, 2A primer layer, 2B primer layer) may have an adhesion force of 3.0gf/inch or more or an adhesion force of 3.5gf/inch or more.

The primer layer has an effect of imparting adhesion between the substrate layer and the barrier layer or improving the refractive index. The material, surface tension, peeling force, and the like for forming each primer layer may be the same or different.

Hard coating

The electrochromic device 100 according to an example may further include a hard coating layer 170 on a surface of the second substrate layer 150 opposite to a surface on which the second barrier layer 140 is laminated (refer to fig. 6).

The hard coating layer 170 may include acrylic resin, silicone resin, urethane resin, epoxy resin, or polyimide resin.

The thickness of the above hard coating layer may be 1 μm to 10 μm, 2 μm to 8 μm, 2 μm to 6 μm, or 2 μm to 5 μm, but is not limited thereto.

The pencil hardness of the hard coat layer may be 3H or more, 4H or more, or 5H or more, but is not limited thereto.

The hard coating layer has an effect of protecting the electrochromic device from external impact and has abrasion resistance, so that excellent hardness can be imparted.

Also, since the thickness of the hard coating layer satisfies the above range, an electrochromic device having flexibility and excellent workability can be realized, and when the thickness of the hard coating layer exceeds the above range, it is difficult to realize flexibility, and if it is less than the above range, it may be easily subjected to external impact.

In a specific example, the flexible electrochromic device 100 may include: a release film layer 160; an adhesive layer 161 formed on the release film layer 160; a 1B primer layer 112 formed on the adhesive layer 161; a first base layer 110 formed on the 1B-th primer layer 112; a 1A primer layer 111 formed on the first base layer 110; a first barrier layer 120 formed on the 1A primer layer 111; a variable light transmittance structure 130 formed on the first barrier layer 120; a second barrier layer 140 formed on the light transmittance variable structure 130; a 2A primer layer 151 formed on the second barrier layer 140; a second base layer 150 formed on the 2A primer layer 151; a 2B primer layer 152 formed on the second base layer 150; and a hard coating layer 170 formed on the second 2B primer layer 152.

Effect and use

Since the electrochromic device has a characteristic that light transmittance reversibly changes when power is applied, light transmittance of sunlight and the like can be selectively controlled by a simple operation such as pressing a button, thereby improving energy efficiency. In particular, when power is applied to the electrochromic device, coloring and discoloration are caused while an electric field is formed between two electrodes, and thus, transmittance can be adjusted for each wavelength of sunlight to realize a heat insulating function and a sunshade function, which is useful. Further, since the electrochromic device can be manufactured into a large-area device at low cost and consumes low power, it can be suitably used as a material for smart windows, smart mirrors, and other next-generation architectural windows. Also, the above electrochromic device is not only thin but also light and flexible, and thus has excellent workability, low risk of damage, can be stored in a roll form, and is easily transported.

The electrochromic device has flexibility while realizing a variable light transmittance function, thereby overcoming the limitation that only a solid structure can be applied in the past, and ensuring the required technical means by simply attaching the electrochromic device to the existing structure such as a transparent window. For example, the above electrochromic device may be applied by simply attaching it to an existing structure such as a transparent window. In particular, as shown in fig. 1, may be attached to one side of the window. More specifically, a cross-sectional view taken along line a-a' in fig. 1 and an enlarged view of a portion to which the electrochromic device is applied are shown in fig. 2. The electrochromic device 100 may be attached to one side of the window 10, and the window 10 may be a flat side or a curved side. The electrochromic device 100 may be attached to the entire surface of the window 10 or only a part thereof. Also, the electrochromic device 100 described above may be inserted inside the window 10. Specifically, it can be applied by interposing the above electrochromic device between a glass substrate and a glass substrate. More specifically, it can be applied by interposing two polyvinyl butyral (PVB) films between laminated glass and laminated glass of a window, and interposing an electrochromic device between the two PVB films, and can be stably inserted into the interior of the window by using heat pressing.

It should be understood that specific embodiments are described below, but various forms including equivalents corresponding to the technical scope of the embodiments and alternatives may be implemented.

Example A1

Step 1: preparation of acrylic resin

1-1) A1L three-necked round-bottomed flask comprising a thermometer, a cooler, a dropping funnel and a mechanical stirrer was prepared, and then immersed in an 80 ℃ thermostatic bath. To the flask were added 300g of ethyl acetate and 1.5g of Azobisisobutyronitrile (AIBN), a radical polymerization initiator, and then, 100 times of rotation stirring was performed per minute using a mechanical stirrer. In this case, the temperature of the cooler was maintained at 10 ℃.

1-2) into another flask were charged 189g of butyl acrylate 63 parts by weight, 27g of methyl methacrylate 9 parts by weight, 51g of 2-hydroxyethyl acrylate 17 parts by weight, and p-dodecylstyrene (C) 10 parts by weight₂₀H₃₂)10g, mixed for 30 minutes using a mechanical stirrer. It was then slowly added to the 1-1 step flask using a dropping funnel.

1-3) after the addition was complete, the temperature of the reactor was maintained at 80 ℃. During the reaction, a sample was collected from the above reaction mixture to determine the weight average Molecular Weight (MW) of the sample. When the desired weight average molecular weight was reached was determined as the reaction completion time, and the reaction was gradually cooled at normal temperature to terminate the reaction. The weight average molecular weight of the obtained compound (liquid acrylic resin) was 70000g/mol and the degree of dispersion was 4.2 as measured by Gel Permeation Chromatography (GPC).

Step 2: making electrochromic devices

A transparent electrode substrate in which an ITO electrode having a surface resistance of 50 Ω/sq, a barrier layer, a primer layer, and a PET base layer (thickness 125 μm) were laminated was disposed in the outermost upper and lower layers.

The coating liquid (C) for the reduction-discoloration layer to be coated on the lower ITO electrode is tungsten oxide (WO)₃) A paste prepared by mixing an acrylic resin ((B), prepared in step 1 above) dissolved in toluene with an aqueous ammonium metatungstate solution (a). In this case, the reductive discoloration layer coating liquid (C) is used in 100 parts by weight of tungsten oxide (WO)₃) For reference, the acrylic resin was mixed so that the content thereof was 3 parts by weight.

Then, the above reductive discoloration layer coating solution (C) was applied to the lower ITO electrode by wet coating, dried at a temperature of 140 ℃ for 5 minutes to form a reductive discoloration layer (thickness 300nm), and prussian blue dye was applied to the upper ITO electrode by wet coating, dried at a temperature of 140 ℃ for 5 minutes to form an oxidative discoloration layer (thickness 400 nm).

An electrochromic device sample (100 mm. times.100 mm) was produced by applying a gel electrolyte (ion conductivity 50. mu.S/cm or more) between the reduction-coloring layer and the oxidation-coloring layer in a thickness of 100 μm and then laminating them. Next, a copper tape was attached to the side surfaces of the upper and lower transparent electrode substrates to form a Bus bar (Bus bar) capable of connecting a power supply.

Examples A2 to A4, comparative examples A1 to A4

Electrochromic device samples were manufactured in the same manner as in example a1, except that the weight ratio of tungsten oxide to acrylic resin in the composition of the reductive discoloration layer, the thickness of the reductive discoloration layer, the coating method of the reductive discoloration layer, and the like were different, as shown in table 1 below.

For the electrochromic devices manufactured in the above examples a1 to a4 and comparative examples a1 to a4, the following physical properties were measured and evaluated, and the results thereof are shown in the following tables 1 to 3.

TABLE 1

The weight of the acrylic resin in the above reductive discoloration layer was calculated as 100 parts by weight of tungsten oxide (WO)₃) For reference, the parts by weight of the acrylic resin are described.

Evaluation example a 1: evaluation of short-term reliability (evaluation of radius of curvature)

In order to deform the fabricated electrochromic device to have a radius of curvature of 17R, 30R, 70R, and 90R, it was wound on a cylinder having a desired radius of curvature, and then observed with the naked eye to evaluate the generation of cracks and the degree of generation.

The case where no cracks were generated was evaluated as "O", the case where the number of cracks was 1 or more and less than 5, or the case where the number of cracks was 2mm or less was 3 or more was evaluated as "micro-cracks", the case where the number of cracks was 5 to 10, or the case where the number of cracks was 5 or more was evaluated as "cracks", the case where the number of cracks was more than 10, or the case where the number of cracks was more than 5 was evaluated as "crack bundles", and the results are shown in table 2 below.

TABLE 2

Evaluation example a 2: evaluating storage effectiveness

In order to deform the electrochromic device to have a radius of curvature of 17R, after it was wound on a cylinder having a radius of curvature of 17R, the initial light transmittance (TTd) was measured in the maximum discolored state₀). Then, the power was turned off and the state of the radius of curvature of 17R was maintained while measuring the light transmittance (TTd) after 12 hours and after 24 hours, respectively₁₂、TTd₂₄)。

And, in order to deform the electrochromic device to have a curvature radius of 17R, after winding it on a cylinder having a curvature radius of 17R, the initial light transmittance is measured in the maximum colored state (TTc)₀). Then, the power was turned off and the state of the radius of curvature of 17R was maintained while measuring the light transmittance after 12 hours and after 24 hours, respectively (TTc)₁₂、TTc₂₄)。

In the measurement of the above light transmittance, the electrochromic device was flattened in its original state and measured using Ultraviolet spectrum (Ultraviolet spectrum) of JASCO corporation. Specifically, the above-mentioned transmittance is a visible light transmittance, which is expressed as an average value of values measured at 5nm intervals in a wavelength range of 380nm to 780nm using an ultraviolet spectrum of JASCO corporation.

The maximum discolored state refers to a state in which a change of less than 1% during 20 seconds under the visible light average transmittance lasts for one minute or more during the discoloring operation of the electrochromic device, and the maximum colored state refers to a state in which a change of less than 1% during 20 seconds under the visible light average transmittance lasts for one minute or more during the coloring operation of the electrochromic device.

Also, when the radius of curvature of the electrochromic device is 17R, in comparative examples a1 to A3 in which cracks or crack bundles are generated, it is difficult to measure meaningful light transmittance due to cracks.

The results of measurement by the above method are shown in table 3.

Evaluation example a 3: evaluation of Long-term reliability

In order to deform the electrochromic device to have a radius of curvature of 17R, the initial light transmittance was measured in the maximum discolored state and in the maximum colored state after it was wound on a cylinder having a radius of curvature of 17R.

Then, the power was turned off and the state of the radius of curvature of 17R was maintained, while the power was turned on again after 24 hours, and the fading and coloring operations were performed, and the light transmittance was measured in the maximum fading state and in the maximum coloring state.

The method for measuring the light transmittance was as described in evaluation example 3.

The results of measurement by the above method are shown in table 3.

TABLE 3

As shown in table 2 above, the electrochromic devices of examples a1 to a4 did not crack even when deformed to a radius of curvature of 17R, whereas comparative example a1 cracks when having a radius of curvature of 70R or less, comparative example a2 cracks when having a radius of curvature of 30R or less, and comparative example A3 cracks when having a radius of curvature of 17R or less. Therefore, it was confirmed that the electrochromic device according to the example can be deformed to have a small radius of curvature.

As shown in Table 3 above, the Δ TTd of examples A1 to A4 was confirmed₁₂A value of 1% or less,. DELTA.TTd₂₄The value is 3% or less, and the light transmittance is maintained at a predetermined level or more even after the power is turned off in the maximum fading state. Likewise, Δ TTc was confirmed for examples A1 to A4₁₂A value of 0.8% or less,. DELTA. TTc₂₄The value is 2% or less, and the light transmittance is maintained at a predetermined level or more even after the power is turned off in the maximum coloring state.

In contrast, when comparative examples a1 to A3 had a radius of curvature of 17R, cracks were generated or a crack beam was difficult to measure meaningful light transmittance, confirming that Δ TTd of comparative example a4₁₂Value Δ TTd₂₄Value Δ TTc₁₂Value and Δ TTc₂₄The value exceeds the above range and the memory effect is reduced.

The decrease in the memory effect as in comparative example a4 means that the transmittance of the electrochromic device does not maintain the desired level of performance when the power is turned off, and thus is not suitable for commercialization as a smart window.

Also, the TTRdc values of examples a1 to a4 have high values of 90% or more, specifically 99.3% or more, and not only can be deformed to have a small radius of curvature, but also can realize an excellent light transmittance variable function after the deformed state continues for several hours.

Therefore, it was confirmed that the electrochromic device according to the example can be applied to a curved window without reducing performance, can maintain a roll shape to reduce logistics costs, and is easy to store and transport.

Example B1

Step 1: preparation of acrylic resin

A1L three-necked round-bottomed flask (flask A) comprising a thermometer, a cooler, a dropping funnel and a mechanical stirrer was prepared, and after adding 300g of ethyl acetate and 1.5g of Azobisisobutyronitrile (AIBN), a radical polymerization initiator was added thereto, 100 times of rotation stirring was performed per minute using the mechanical stirrer in a thermostatic bath at 80 ℃. In this case, the temperature of the cooler was maintained at 10 ℃. After 189g of butyl acrylate, 27g of methyl methacrylate, 51g of 2-hydroxyethyl acrylate and 30g of p-dodecylstyrene were charged into the other flask (flask B), they were mixed for 30 minutes using a mechanical stirrer, and then slowly added to the former flask (flask A) using a dropping funnel, and polymerization was carried out while maintaining the temperature at 80 ℃. When the desired weight average molecular weight was reached, the reaction was gradually cooled at ordinary temperature to terminate the reaction to obtain an acrylic resin, and the weight average molecular weight was 70000g/mol and the degree of dispersion was 4.2 as measured by Gel Permeation Chromatography (GPC).

Step 2: manufacture of electrochromic devices

2 transparent electrode substrates in which a primer layer, a barrier layer, and an ITO electrode layer (surface resistance of 50 Ω/s) were formed on a PET base layer (thickness 125 μm) were prepared and used as upper and lower plates.

The acrylic resin (prepared in the above step 1) was dissolved in toluene and then mixed with an aqueous solution of ammonium metatungstate to prepare tungsten oxide (WO)₃) A paste of 100 parts by weight of tungsten oxide (WO)₃) Contains 3 parts by weight of an acrylic resin. The tungsten oxide paste was applied to the ITO electrode layer of the lower plate by wet coating and dried at a temperature of 140 c for 5 minutes to form a reductive discoloration layer (thickness 300 nm).

And, a prussian blue dye was applied to the ITO electrode layer of the above upper plate by wet coating, and dried at a temperature of 140 ℃ for 5 minutes to form an oxidation-discolored layer (thickness 400 nm).

A gel electrolyte (ion conductivity of 50. mu.S/cm or more) was applied between the reduction coloring layer and the oxidation coloring layer at a thickness of 100 μm and then bonded to produce an electrochromic device (width 300 mm. times. length 200 mm). Then, a copper tape is adhered to the side surfaces of the ITO electrode layers of the upper and lower plates to form a bus bar capable of connecting a power supply.

Examples B2 to B9, comparative examples B1 and B2

Electrochromic devices were manufactured in the same manner as in example B1, except that the weight ratio of tungsten oxide to acrylic resin and/or the thickness of the reductive coloration layer in the composition of the reductive coloration layer were different, as shown in tables 5 to 8 below.

Test examples

The following tests were performed on the electrochromic devices manufactured in the above examples and comparative examples.

First, test piece size

Width 300mm x length 200mm x thickness about 350 μm

Second, test method

-bending test: the test piece is bent so that the distance between both lateral ends thereof is 25% of the horizontal length, and then the original shape is restored (repeated 7-10 times per minute).

-duration test: the bent state was maintained for a prescribed time so that the distance between both ends in the lateral direction of the test piece was 25% of the horizontal length.

-memory testing: after applying power to the test piece to reach the maximum fading state, the power is turned off and kept for a predetermined time.

Third, measuring the transmittance

After applying power to the test piece to the maximum discolored state or the maximum colored state, the average transmittance of visible light was measured at 4 fulcrums P2 spaced 30mm from the edge of the test piece and at the center fulcrum P1 of the test piece, respectively, as shown in fig. 10. The visible light average transmittance is an average value of a plurality of values obtained by measuring the transmittance at 5nm intervals in a wavelength range of 380 to 780 nm.

Fourth, measuring data

-TT _ 0: light transmittance measured in maximum fading state in initial stage (before test)

-TT — 0': light transmittance measured in maximum coloring state in initial stage (before test)

-TT _ B30: light transmittance measured in the maximum fading state after 30 times of repeated bending tests

-TT _ B30': light transmittance measured in the maximum colored state after 30 times of bending test

-TT _ B50: light transmittance measured in the maximum fading state after repeating 50 times of bending test

-TT _ B50': light transmittance measured in the maximum colored state after repeating 50 times of bending test

-TT — 100H: light transmittance measured in the maximum fading state after carrying out the duration test for 100 hours

-TT _ 100H': light transmittance measured in the maximum colored state after carrying out the duration test for 100 hours

-TT _100H _ B30: light transmittance measured in the maximum fading state after repeated bending test 30 times after carrying out the duration test for 100 hours

-TT _100H _ B30': light transmittance measured in the maximum colored state after repeating 30 times of bending test after performing the continuous test for 100 hours

-TT _ B30_ M12H: light transmittance measured after a 12-hour memory test in the maximum fading state after 30-time repeated bending tests

-TT _ B30_ M12H': light transmittance measured after conducting a memory test for 12 hours in the maximum colored state after repeating the bending test 30 times

The data of the above measurement are summarized in the form of table 4 below in tables 5 to 8.

TABLE 4

TABLE 5

TABLE 6

TABLE 7

TABLE 8

e. Calculation of formula using measured data

The following formula was calculated using the measured data and summarized in table 9 below.

(i) Light transmittance change before and after 30 times of repeated bending test

△TT_B30(％)＝│TT_B30－TT_0│

(ii) Change in light transmittance operation Range before and after 30-time bending test

△TT_B30_d(％)＝││TT_B30－TT_B30'│－│TT_0－TT_0'││

(iii) Light transmittance change before and after 50 times of repeated bending test

△TT_B50(％)＝│TT_B50－TT_0│

(iv) Change in light transmittance before and after 100 hours of holding in a bent state

△TT_100H(％)＝│TT_100H－TT_0│

(v) After keeping the bent state for 100 hours, the transmittance after 30 bending tests was repeated

△TT_100H_B30(％)＝│TT_100H_B30－TT_0│

(vi) After 30 times of bending test was repeated, the power was turned off to a maximum discolored state, and the transmittance was maintained for 12 hours

△TT_B30_M12H(％)＝│TT_B30_M12H－TT_0│

TABLE 9

Fifthly, explaining the results

As shown in the above table, the electrochromic device of comparative example B1 generated micro-cracks after repeating the bending test 30 times, so that the light transmittance was changed by more than 1% from the initial state. In addition, the electrochromic device of comparative example B2 was unable to be handled because a large number of cracks were generated after 10 times of bending and the light transmittance was greatly reduced, and a large number of cracks were generated on all surfaces in 30 times of bending tests.

However, the electrochromic devices of examples B1 to B9 all measured that the light transmittance change was 1% or less with respect to the initial state even after 30 bending tests were repeated.

In particular, the electrochromic devices of examples B1 to B3 among them all measured a change in light transmittance of 1% or less from the initial state after repeated or continuous bending tests or tests in which the power was turned off and the state was maintained.

In addition, it is understood that in examples B4 to B6, the fading maintaining (storage) function and the bending property at a prescribed level of thickness are affected by the content of the additive. Specifically, in example B4, micro-cracks were generated when the bending was repeated 50 times, and in examples B4 and B6, when the power was applied to reach the maximum discolored state after the bending was repeated 30 times and then the power was turned off and maintained for 12 hours, the light transmittance was slightly decreased.

Further, it is understood that in examples B7 to B9, when the thickness of the tungsten oxide is small, the operation range of the light transmittance and the memory function are affected by the content of the additive.