KR102666775B1 - Ligth transmittance variable panel implementable multi image mode and display device having the same - Google Patents

Abstract

The present invention relates to a variable transmittance panel having an electrochromic layer containing electrochromic particles, an electrolyte, and reflective metal cations, and a display device including the same. The variable transmittance panel of the present invention can implement various image modes, such as a shading mode that blocks light, a transmission mode that transmits light, and a reflection mode that can express a background image, depending on the magnitude of the applied voltage. Unlike when a simple reflection mode is implemented, the image expressed by the display device and the background image are displayed in an overlapping manner, according to the present invention, various image modes can be implemented as needed. By switching the display mode, you can prevent background images from being displayed and improve visibility by selectively displaying only images displayed on the display device.

Description

Transmittance variable panel capable of implementing multi-image mode and display device including same {LIGTH TRANSMITTANCE VARIABLE PANEL IMPLEMENTABLE MULTI IMAGE MODE AND DISPLAY DEVICE HAVING THE SAME}

The present invention relates to a panel for a display device, and more specifically, to a variable transmittance panel that can easily implement multi-image modes and a display device including the same.

As the information society progresses, interest in various flat panel displays with excellent image quality is increasing. Among flat panel displays, liquid crystal displays (LCD) and organic light emitting diode (OLED) displays are widely used.

Liquid crystal displays display images using the optical anisotropy and polarization properties of liquid crystal molecules. For example, in a liquid crystal display device, pixel electrodes and common electrodes are alternately arranged on a first substrate, and a liquid crystal layer containing liquid crystal molecules is interposed between the first substrate and the second substrate facing each other. Meanwhile, an organic light emitting diode display device emits light by forming an organic light emitting layer between an anode and a cathode. Holes injected from the anode and electrons injected from the cathode combine in the organic light-emitting layer to form an exciton, and the exciton emits light as it transitions from the excited state to the ground state.

Recently, instead of liquid crystal displays or organic light emitting diode displays, display devices that display images according to the discoloration or movement of particles according to the application of power have been proposed. As such a display device, a reflective display device that can implement a reflective/mirror mode by adopting an electrophoresis method, a method using electrochromic particles, etc. is known.

However, in a conventional reflective display device, the background image is overlapped with the image to be displayed, thereby reducing visibility. Therefore, conventional reflective display devices focus on conveying text-oriented information, and it is difficult to provide high-quality video.

In relation to these problems with conventional reflective display devices, Korean Patent Publication No. 2016-003997 proposes a mirror display with a variable retarder attached to the top of an OLED-based mirror display panel. However, the mirror display proposed in the above-mentioned published patent is intended to improve visibility by an external light source and cannot be considered to have improved the visibility of the display device. Additionally, it can be applied to rearview mirrors or side mirrors inside a vehicle, and is inappropriate to be used as a display device in a general indoor environment.

The purpose of the present invention is to provide a variable transmittance panel and display device that can easily implement various multi-image modes.

Another object of the present invention is to provide a variable transmittance panel and display device that can improve visibility of images provided by the display device.

According to one aspect of the present invention having the above-described object, the electrochromic layer located between two transparent electrodes includes electrochromic particles, an electrolyte that mediates the oxidation-reduction reaction of the electrochromic particles, and a reflective metal. Provides a variable permeability panel containing positive ions.

In one example, a reflective metal cation may dissociate in the electrolyte from a metal salt that is a chloride, sulfur oxide, nitride, or carbonate of a reflective metal (e.g., silver, aluminum, copper, or palladium).

The metal salt may be included in the electrolyte in an amount of 0.1 to 5% by weight.

In one exemplary embodiment, the electrochromic particles are reduced at a first voltage, and the reflective metal cations may migrate to the second transparent electrode at a second voltage that is lower than the first voltage.

According to another aspect of the present invention, the present invention provides a display device consisting of the variable transmittance panel and a display panel located on one side of the variable transmittance panel and including a display portion and a transparent portion.

The variable transmittance panel according to the present invention includes an electrochromic layer located between transparent electrodes, and the electrochromic layer includes electrochromic particles and an electrolyte as well as reflective metal cations.

Depending on the applied voltage, the panel with variable transmittance facilitates multi-image modes such as a light blocking (black) mode that blocks external light, a transmission (transparent) mode that transmits external light, as well as a reflective mode (mirror mode) that reflects external light. It can be implemented easily.

In reflection mode, the transmission mode can be quickly implemented simply by changing the intensity of the voltage applied to the variable transmittance panel, preventing the background image from being displayed on the display device, allowing only the image provided by the display device to be displayed, thereby improving visibility. It improves.

Meanwhile, by using an organic material capable of rapid color change as an electrochromic material and using electrochromic particles with a core-shell structure, changes in light blocking mode and transmission mode can be quickly implemented.

In addition, since the variable permeability panel of the present invention can be formed into a film using a solid electrolyte, the problem of fluid leakage in the conventional variable permeability panel using a liquid electrolyte can be prevented, and a thin variable permeability panel can be manufactured. .

In addition, in the case of a display device including the variable transmittance panel of the present invention, visibility and brightness and contrast ratio can be improved due to excellent transmittance, reflectance, and light blocking characteristics.

1 is a cross-sectional view schematically showing a variable transmittance panel capable of implementing various imaging modes according to an exemplary embodiment of the present invention.
2 and 3 are respectively schematic cross-sectional views of electrochromic particles that can be used in accordance with exemplary embodiments of the present invention.
Figure 4 is a cross-sectional view schematically showing a variable transmittance panel in which a light blocking mode (black mode) is implemented according to an exemplary embodiment of the present invention.
Figure 5 is a cross-sectional view schematically showing a variable transmittance panel in which a transmission mode (transparent mode) is implemented according to an exemplary embodiment of the present invention.
Figure 6 is a cross-sectional view schematically showing a variable transmittance panel in which a reflection mode (mirror mode) is implemented according to an exemplary embodiment of the present invention.
Figure 7 is a cross-sectional view schematically showing a display device including a variable transmittance panel according to an exemplary embodiment of the present invention.
Figure 8 is a cross-sectional view schematically showing a transparent display panel according to an exemplary embodiment of the present invention.
Figure 9 is a graph showing the results of measuring the intensity of driving voltage, transmittance, and reflectance over time of a unit electrochromic device, which is a variable transmittance panel manufactured according to an exemplary embodiment of the present invention.
Figure 10 is a photograph of the reflection mode of a unit electrochromic device manufactured according to another exemplary embodiment of the present invention.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings where necessary.

1 is a cross-sectional view schematically showing a variable transmittance panel capable of implementing various imaging modes according to an exemplary embodiment of the present invention. As shown in FIG. 1, the transmittance variable panel 100 according to an exemplary embodiment of the present invention has first and second substrates 110 and 120 facing each other, and is located on the first substrate 110. It is located between the first transparent electrode 130 and the second transparent electrode 140 located on the second substrate 120, and the first and second transparent electrodes 130 and 140, and electrochromic particles ( 160), an electrochromic layer 150 including an electrolyte 170 and reflective metal cations 180, and a counter electrode 190.

The first substrate 110 and the second substrate 120 may be made of glass or plastic, respectively. For example, the first substrate 110 and the second substrate 120 each include polyethersulfone (PES), polyacrylate (PAR), polyetherimide (PEI), and polyphenylene sulfide. (polyphenylene sulfide (PPS), polyimide (PI), polycarbonate (PC), polyethyeleneterepthalate (PET), polyethylenenaphthalate (PEN), cellulose triacetate (TAC) and/or may be made of a plastic material such as cellulose acetate propinonate (CAP).

Each of the first transparent electrode 130 and the second transparent electrode 140 is made of a transparent conductive material. For example, the first transparent electrode 130 and the second transparent electrode 140 are each made of indium-tin-oxide (indium-tin-oxide, ITO) and indium-zinc-oxide (IZO). , zinc oxide (ZnO), tin oxide (SnO ₂ ), aluminum-doped zinc oxide (Al:ZnO, AZO), and antimony-doped tin oxide (SnO2:Sb, ATO). Since the variable transmittance panel 100 according to the present invention must have high light transmittance in transmission mode (transmission mode), it may be desirable to form the first and second transparent electrodes 130 and 140 of a transparent conductive material. In contrast, when the first and second transparent electrodes 130 and 140 are made of a low-resistance metal material such as aluminum, copper, palladium, or a mixture thereof, they may have a thin thickness to allow light to pass through.

If necessary, the first and second transparent electrodes 130, 140 are made of a low-resistance metal such as aluminum, copper, palladium, and mixtures thereof, and a transparent conductive material such as ITO, IZO, ZnO, SnO ₂ , AZO, and ATO. You can also use what was deposited. At this time, the low-resistance metal may have a mesh shape. In the case of using a transparent electrode in which a transparent conductive material is deposited on a mesh-shaped low-resistance metal, the response speed of the electrochromic particles 160 is greatly improved, making it possible to achieve rapid color change upon application of power.

The electrochromic layer 150 is located between the first and second substrates 110 and 120, that is, between the first and second transparent electrodes 130 and 140, and contains electrochromic particles 160 and electrolyte 170. and reflective metal cations (180). As will be seen later, the electrochromic particles 160 may have a core-shell structure. For example, the electrochromic particles 160 having a core-shell structure may be dispersed in a transparent electrolyte fluid or mixed with a transparent solid electrolyte or polymer/gel electrolyte to form a coating or film.

Electrochromic particles 160 having a core-shell structure according to the present invention will be described. FIG. 2 is a diagram schematically showing electrochromic particles 160A having a core-shell structure consisting of a single core according to an exemplary embodiment of the present invention. As shown in FIG. 2, the electrochromic particles 160A according to an exemplary embodiment of the present invention include a core 162 and a shell 164 surrounding the core 162.

The core 162 may be made of a conductive metal oxide showing excellent transmittance to visible light, a non-conducting metal oxide having an excellent specific surface area, or a mixture thereof. The conductive metal oxide may be, for example, nanoparticles of metal oxide with an average diameter of 30 to 200 nm. The conductive metal oxide may be selected from the group consisting of ITO, IZO, AZO, ATO, fluorine-doped tin-oxide (FTO), and combinations thereof. Meanwhile, the non-conductive metal oxide may be, for example, metal oxide nanoparticles having a specific surface area of 100 m2/g or more and an average diameter of 10 to 100 nm. The non-conductive metal oxide may be selected from the group consisting of titania (TiO ₂ ), silica (SiO ₂ ), zinc oxide (ZnO), zirconia (ZrO ₂ ), and combinations thereof.

The core 162 is not limited to the above-mentioned materials, and in addition, other organic materials, inorganic materials, or organic-inorganic mixtures with high transmittance to visible light and excellent electrical conductivity, and/or non-conductive materials with a relatively large specific surface area. Organic materials, inorganic materials or organic-inorganic mixtures may also be applied.

Meanwhile, the shell 164 may be made of a material that can change color depending on the application of electricity. In one exemplary embodiment, shell 164 is a reductively colored material capable of changing color by an oxidation-reduction reaction. For example, the shell 164 is made of tungsten oxide (WO ₃ ), molybdenum oxide (MoO ₃ ), niobium oxide (Nb ₂ 0 ₅ ), titania (TiO ₂ ), tantalum oxide (Ta ₂ O ₅ ), oxide Nickel _{( NiO 2 ) ,} nickel _{tungsten oxide ( Ni} ), rhodium oxide (RhO ₂ ), and/or vanadium oxide (V ₂ O ₅ ).

In another alternative embodiment, shell 164 may be made of an organic electrochromic material. For example, the shell 164 may be made of a conductive polymer such as polyaniline or polythiophene.

Optionally, the shell 164 may be made of an electrochromic material, which is an organic material having a viologen structure to which a bipyridinium salt is linked. 1-ethyl-1'-(2-phosphonoethyl)-4,4'-bipyridinium dichloride (1-ethyl-1'-(2-phosphonoethyl)-) is an organic electrochromic material with a viologen structure. 4,4'-bipyridinum dichloride). Alternatively, the organic electrochromic material having a viologen structure may be represented by Formula 1 or Formula 2 below.

Formula 1

Formula 2

_{( In} ^Formulas ₁ ^and ₂ ^{, ​} _{​ ​} ^​ _{​ ​ ​} ^​ _​ Silver hydrogen atom, C1~C30 alkyl group, C2~C30 alkenyl group, C2~C30 alkynyl group, C1~C30 alkoxy group, C4~C30 cycloalkyl group, C4~C30 heterocycloalkyl group, C5~C30 aryl group, C5~C30 hetero R ₂ and R ₃ are each independently selected from the group consisting of an aryl group, a C5 to C30 aralkyl group, a C5 to C30 heteroaralkyl group, a C5 to C30 aryloxy group, and a C5 to C30 heteroaryloxy group; Consists of carboxylic acid (-COOH), sulfonic acid (-SO ₃ H ₂ ), boronic acid (B(OH) ₂ ), phosphonic acid (PO ₃ H ₂ ), and phosphinic acid (PO ₂ H ₂ ) linked through an alkyl group. R ₄ is a halogen-substituted C1-C10 alkyl group or a halogen-substituted C1-C10 alkoxy group)

When an electrochromic material having a viologen structure, including compounds represented by Formulas 1 and 2, is used as the shell 164, light transmittance is improved when no electric field is applied, and the shell 164 is maintained even at low voltages. This discoloration to black can improve light blocking efficiency.

When the electrochromic particles (160A) have a spherical core-shell structure, the specific surface area may increase compared to the plate-shaped particle. Therefore, the reaction speed to the application of an electric field can be improved, and a discoloration reaction can occur even at a low driving voltage.

Figure 3 is a diagram schematically showing electrochromic particles having a core-shell structure consisting of two cores according to another exemplary embodiment of the present invention. As shown in FIG. 3, the electrochromic particles 160B according to another exemplary embodiment of the present invention include a core 162 consisting of a first core 162a and a second core 162b, and a core 162 ) includes a shell 164 surrounding the

For example, the first core 162a is a conductive metal oxide that exhibits excellent transmittance to visible light and has good electron mobility. The first core 162a may be, for example, nanoparticles of conductive metal oxide having an average diameter of 30 to 200 nm. The conductive metal oxide that can be used as the first core 112 may be selected from the group consisting of ITO, IZO, ATO, FTO, AZO, and combinations thereof. The first core 162a is not limited to the above-described materials, and may further include other organic materials, inorganic materials, or organic-inorganic mixtures that have high transmittance to visible light and excellent electrical conductivity.

The second core 162b surrounds the first core 162a, has a relatively large specific surface area, and is a non-conductive metal oxide with high transmittance to visible light. The second core 162b may be, for example, nanoparticles of non-conductive metal oxide having a specific surface area of 100 m 2 /g or more and an average diameter of 10 to 100 nm. A non-conductive metal oxide that can be used as the second core 162b may be selected from the group consisting of TiO ₂ , SiO ₂ , ZnO, ZrO ₂ , and combinations thereof. The second core 162b is not limited to the above-described materials and may include a non-conductive organic material with a relatively large specific surface area, an inorganic material, or an organic-inorganic mixture.

When the core 162 constituting the electrochromic particles 160B is composed of a double core of a conductive first core 162a and a non-conductive second core 162b with a large specific surface area, the light transmittance and light blocking degree is improved and has the advantage of low-power consumption. For example, when the first core 162a is made of ITO with excellent electron transfer characteristics, electron mobility to the shell 164 increases in the ON state, making discoloration in the shell 164 easier.

Additionally, since the second core 162b is made of TiO ₂ or the like, which has high transmittance to visible light, it has high transmittance in the OFF state. In addition, since the non-conductive metal oxide constituting the second core 162b has a large specific surface area, the second core 162b is combined with the shell 164 to improve bistability. Accordingly, power consumption for driving the electrochromic particles 160B can also be reduced. In other words, due to high bistability, the light blocking state can be maintained for a certain period of time even when the application of voltage is stopped, which has an advantage in terms of power consumption. Meanwhile, the shell 164 may be a metal oxide such as tungsten oxide, a conductive polymer such as polyaniline, or an organic material having a viologen structure containing a compound represented by Formula 1 or Formula 2.

Additionally, the electrochromic layer 150 includes an electrolyte 170 in addition to the electrochromic particles 160. For example, electrolyte 170 may be composed of a solid electrolyte. When a liquid electrolyte is used, there is a risk of leakage of the fluid electrolyte. For example, the electrolyte 170 is a gel-type or polymer-based electrolyte containing a dissolved lithium salt. Preferably, the medium of the electrolyte 170 may be made of a solid state electrolyte (SSE) that can be heat-cured or photo-cured and has relatively low electrical conductivity and excellent ionic conductivity.

In an exemplary embodiment, the gel-forming polymer capable of constituting a gel-type electrolyte or the polymer capable of constituting a polymer-based electrolyte is poly(vinylidene fluoride-co-hexafluoropropylene) (poly(vinylidenefluoride-co -hexafluropro propylene); PVDF-HFP), polyacrylonitrile (PAN), poly(methyl methacrylate) (PMMA), polyacrylic acid, unmodified or modified polyacrylate or polyurethane acrylate, poly(2- poly(2-acrylamido-2-methyl-1-propanesulfonic acid, Poly-AMPS), unmodified or modified polyethylene oxide (PEO) or polyethylene glycol (PEG) and/or polyvinyl chloride, etc. may be used.

The gel-type electrolyte or polymer-based electrolyte may contain lithium salt at a concentration of 0.1 to 1 mol/l. Lithium salts that may be included in the electrolyte include, for example, lithium bis((trifluoromethyl)sulfonyl)amide, LfTf2N, lithium trifluoromethanesulfonate, LiTfO, LiCF ₃ SO ₃ ), lithium bis(trifluoromethane)sulfonamide (LiTFSI), or lithium perchlorate (LiClO ₄ ), but the present invention is not limited thereto.

Meanwhile, the electrochromic layer 150 may include reflective metal cations 180. The reflective metal cation 180 may be generated when a metal salt containing a reflective metal such as silver (Ag), aluminum (Al), copper (Cu), or palladium (Pd) dissociates in the electrolyte 170. . The metal salt capable of generating the reflective metal cation 180 is not particularly limited, but may be chloride, sulfate, nitrate, or carbonate of the reflective metal.

In one exemplary embodiment, metal salts that can dissociate into reflective metal cations 180 include silver nitrate (AgNO ₃ ), silver chloride (AgCl), silver sulfate (Ag ₂ SO ₄ ), silver carbonate (Ag ₂ CO ₃ ), and It may be any one silver salt selected from the group consisting of combinations thereof, but the present invention is not limited thereto.

As will be described later, depending on the strength of the voltage applied to the variable permeability panel 100, the reflective metal cations 180 generated by dissociation of the reflective metal salt move up and down the variable permeability panel 100 to implement various modes. .

At this time, the metal salt that can dissociate into the reflective metal cation 180 may be added to the electrolyte 170 at a rate of 0.1 to 5% by weight, preferably 0.5 to 3% by weight. When the content of the metal salt in the electrolyte 170 is less than 0.1% by weight, the amount of dissociated reflective metal cations 180 is small, making it difficult to implement various display modes according to the movement of the reflective metal cations 180. In addition, when the content of the metal salt exceeds 5% by weight, the content of other components in the electrolyte 170 decreases, so the color of the electrochromic particles 160 may change due to the oxidation-reduction reaction in the electrolyte 170. It may not perform smoothly. In addition, there is a risk that the reflective metal cations 180 may aggregate and cannot move within the electrolyte 170, making it impossible to implement various display modes.

For example, the electrochromic layer 150 including electrochromic particles 160, electrolyte 170, and reflective metal cations 180 is formed on the first transparent electrode 130 or the second transparent electrode 140. It is formed to a thickness of 200 ㎛. If the thickness of the electrochromic layer 150 is less than 20 ㎛, the device driving characteristics of the variable transmittance panel 100 may deteriorate. Additionally, if the thickness of the electrochromic layer 150 exceeds 200 ㎛, the response speed of the device may become slow and bleeding into adjacent pixels may occur.

Meanwhile, a counter electrode 190 is located between the second transparent electrode 140 and the electrochromic layer 150. The counter electrode 190 promotes the oxidation-reduction reaction caused by the electric field in the electrochromic layer 150 and facilitates the movement of ions present in the electrolyte 170 to reduce the electrochromic particles 160. The counter electrode 190 may be made of a material with high ionic conductivity but low electrical conductivity, for example, an electron-accepting material.

For example, the counter electrode 190 is cerium oxide (CeO ₂ ), TiO ₂ , tungsten oxide (WO ₃ ), nickel oxide (NiO), molybdenum oxide (MoO ₃ ), vanadium oxide (V ₂ O ₅ ), and these. It may be made of a metal oxide selected from the group consisting of a combination of. At this time, the counter electrode 180 can be formed by applying the dispersed solution of these metal oxides on the second transparent electrode 140, followed by drying and sintering. Optionally, the counter electrode 190 is coated with a second transparent layer by deposition from the vapor phase of these metal oxides, for example, by chemical vapor deposition (CVD) or physical vapor deposition (PVD). It may be stacked on the electrode 140.

In another alternative embodiment, counter electrode 190 is selected from hydroquinone, methylhydroquinone, methoxyhydroquinone, acetylhydroquinone, dimethylhydroquinone, trimethylhydroquinone, ethylhydroquinone, butylhydroquinone, t-butylhydroquinone. Hydroquinone-based compounds such as rice paddy; Metallocene, methylmetallocene, dimethylmetallocene, acetylmetallocene, ethylmetallocene, vinylmetallocene, diphenylmetallocene, toxy-methylmetallocene, butylmetallocene, t-butylmetal. Metallocene-based compounds such as locene and chloromethyl metallocene may be used, but are not limited thereto.

In another alternative embodiment, the counter electrode 190 is a metallocene-based polymer, such as poly(3,4-ethylenedioxythiophene) (PEDOT) or a ferrocene-based polymer. ) It may be made of a material selected from the group consisting of polymers or derivatives, diphenylamine, triphenylamine, phenothiazine-based polymers, and/or phenoxazine-based polymers. For example, the counter electrode 190 may be made of an acrylic copolymer containing a metallocene moiety and triarylamine, as described in Korean Patent Publication No. 10-2016-0055352. In another optional embodiment, the counter electrode 190 is a metallocene-based polymer having a repeating unit represented by Formula 3 to Formula 4 below, or a metallocene-based polymer having a repeating unit represented by Formula 5 (e.g., vinyl ferrocene polymer).

Formula 3

Formula 4

Formula 5

(In Formulas 3 to 5, M is a transition metal, such as titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), selected from the group consisting of ruthenium (Ru), osmium (Os), and palladium (Pd), and in Formula 3, R ₅ is a C1-C10 straight or branched alkyl group)

In one exemplary embodiment, counter electrode 190 is comprised of a thickness of 200 to 800 nm. If the thickness of the counter electrode 190 is less than 200 nm, the driving characteristics of the electrochromic layer 150 may deteriorate, and if the thickness of the counter electrode 190 exceeds 800 nm, the resistance of the electrochromic layer 150 may decrease due to an increase. ), the response speed may decrease.

The variable transmittance panel 100 having the above-described configuration can implement various display modes depending on the application of voltage. Below, the intensity of the voltage will be described focusing on the second transparent electrode 140, but this is only for convenience of explanation and the present invention is not limited thereto. As an example, Figure 4 is a cross-sectional view schematically showing a variable transmittance panel in which a light blocking mode (black mode) is implemented according to an exemplary embodiment of the present invention.

As shown in FIG. 4, in order to implement a light blocking mode, a first voltage is applied to the variable transmittance panel 100. For example, a positive (+) voltage is applied to the second transparent electrode 140, and a negative (-) voltage is applied to the first transparent electrode 130. As electrons are supplied to the first transparent electrode 130, a reduction reaction occurs in which electrons are supplied to the electrochromic particles 160 located close to the first transparent electrode 130, and the electrochromic particles 160 are in a transparent state. changes color to a certain color.

For example, the first voltage may be +1.0 to +3.0V based on the second transparent electrode 140. If the intensity of the first voltage is less than +1.0V, the reductive discoloration in the electrochromic particles 160 is not sufficient and an efficient light-shielding mode may not be implemented. On the other hand, if the intensity of the first voltage exceeds +3.0V, there is a risk that the electrochromic material may undergo secondary reduction and the electrochromic properties may deteriorate.

The reflective metal cation 180 may move toward the electrode of opposite polarity along the electric field generated by the voltage applied between the first and second transparent electrodes 130 and 140 constituting the variable permeability panel 100. . When implementing the light-shielding mode, the reflective metal cations 180, which can function as a reflective material, are electrochromic particles on the side of the first transparent electrode 130, which is rich in electrons, which are oppositely charged particles, when a negative voltage is applied. (160) Move to nearby area. While the electrochromic particles 160 have a size of approximately tens to hundreds of nm, the reflective metal cations 180 in an ionic state have a size of only a few angstroms (Å). Additionally, because the reflective metal cation 180 is in an ionic state, it is not adsorbed or bonded to the surface of the electrochromic particle 160.

Therefore, the reflective metal cations 180 that move near the electrochromic particles 160 pass through the pores between the electrochromic particles 160 to an electrode with opposite polarity, that is, the first transparent electrode 130 rich in electrons. ) moves toward the interface. Since the reflective metal cations 180 penetrate between the pores of the electrochromic particles 160 and are located on the top of the first transparent electrode 130, external light incident from the outside of the variable transmittance panel 100 is reflected by the reflective metal cations 180. ) cannot be reached. External light is blocked by the electrochromic particles 160 discolored to black, etc., thereby implementing a light blocking mode.

At this time, the magnitude of the first voltage that causes reductive discoloration of the electrochromic particles 160 depends on the type of reductive discoloration material, the oxidation voltage of the counter electrode 190, the ion transfer ability of the electrolyte 170, and the first transparent electrode 130. ) is related to the resistance of That is, the lower the oxidation voltage of the counter electrode 190, the better the ion transport ability of the electrolyte 170, and the lower the resistance of the first transparent electrode 130, the lower the driving voltage of the device itself. The magnitude of the first voltage required for reductive color change of the electrochromic particles 160 may vary.

For example, when metal oxide is used as an electrochromic material, the intensity of the first voltage for reduction color change is 1.1 to 3V. When using a polymer such as polyaniline as an electrochromic material, the intensity of the first voltage for reductive color change is 1 to 1.5 V. On the other hand, when a material having a viologen structure is used as the electrochromic material, the intensity of the first voltage for reduction color change may be 1.1 to 1.3 V. However, the present invention is not limited to this.

Meanwhile, Figure 5 is a cross-sectional view schematically showing a variable transmittance panel in which a transmission mode (transparent mode) is implemented according to an exemplary embodiment of the present invention. In the OFF state in which no voltage is applied to the transmittance variable panel 100, reductive discoloration does not occur in the electrochromic particles 160, and the electrochromic particles 160 are oxidized and converted to their initial transparent color. The reflective metal cations 180 are uniformly dispersed in the electrochromic layer 160, specifically the electrolyte 170. External light incident on the variable transmittance panel 100 may pass through the electrolyte 170 and the electrochromic particles 160 to implement a transmission mode.

In the drawing, for convenience of explanation, the first transparent electrode 130 and the second transparent electrode 140 are shown in a state where no voltage is applied. However, a predetermined voltage may be applied to implement the transmission mode. For example, the voltage between the first transparent electrode 130 and the second transparent electrode 140 is lower than the first voltage for reduction and discoloration of the electrochromic particles 160, and the reflective metal cation 180, which will be described later, is applied to the second transparent electrode 140. Transmission mode can be implemented even when a voltage higher than the second voltage (see FIG. 6) required to move toward the electrode 140 is applied. For example, when implementing the transmission mode of the variable transmittance panel 100, the voltage applied to the first transparent electrode 130 and the second transparent electrode 140 is -0.5 to +0.5V, preferably -0.2 to +0.2. V, more preferably -0.2 to 0V.

In addition, Figure 6 is a cross-sectional view schematically showing a variable transmittance panel in which a reflection mode (mirror mode) is implemented according to an exemplary embodiment of the present invention. A second voltage having a potential opposite to that of the light blocking mode shown in FIG. 4 is applied to the first transparent electrode 130 and the second transparent electrode 140 constituting the variable transmittance panel 100. Specifically, a positive (+) voltage is applied to the first transparent electrode 130, and a negative (-) voltage is applied to the second transparent electrode 140. Accordingly, electrons move toward the second transparent electrode 140.

Because reductive discoloration does not occur, the electrochromic particles 160 are transparent. Meanwhile, the reflective metal positive ions 180 move toward the upper second transparent electrode 140, which is of opposite polarity, that is, negatively charged, and are arranged along the second transparent electrode 140, forming a kind of 'reflective electrode' or It forms a ‘reflector’. Accordingly, external light incident on the variable transmittance panel 100 is reflected by the reflective metal positive ions 180 arranged on the upper second transparent electrode 140, and a reflection mode can be implemented.

The second voltage may be -1.0 to -1.3V based on the second transparent electrode 140. If the second voltage exceeds -1.0V (for example, -0.5V), the reflective metal cations 180 may not sufficiently move toward the second transparent electrode 140, so the reflection mode may not be efficiently implemented. there is. On the other hand, when the second voltage is less than -1.3V (for example, -2.0V), the reflective metal cation (180) moves toward the second transparent electrode 140 due to strong interaction between the reflective metal cation (180). ) is aggregation. Accordingly, as the driving cycle consisting of shading mode, transmission mode, and reflection mode is repeated according to voltage conversion, there is a risk that switching between multi-display modes may become difficult or the response speed due to mode conversion may decrease.

As described above, the variable transmittance panel 100 according to the present invention includes electrochromic particles 160 capable of changing color depending on the applied voltage, a lower first transparent electrode 130 and an upper electrode within the electrolyte 170. It contains reflective metal cations 180 that move to the second transparent electrode 140. Accordingly, by adjusting the applied voltage, it is possible to easily implement shading mode (black mode), transmission mode (transparent mode), and reflection mode (mirror mode). Conventional reflective display devices have a problem in that visibility is reduced as the image to be displayed on the display device overlaps with the background image.

However, since the variable transmittance panel 100 according to the present invention is capable of various display modes, it is possible to implement not only a transparent display device but also a reflective display device. For example, when driving an image to be expressed on a display device, if there is a problem with reduced visibility due to reflection of the background image due to reflection mode, adjust the size of the applied voltage and switch to shading mode or transparent mode to hide the background. By preventing images from being reflected on the display device, visibility of the image to be expressed on the display device can be improved.

Next, a display device using a variable transmittance panel capable of implementing a multi-display mode according to the present invention will be described. FIG. 7 is a schematic cross-sectional view of a display device including a variable transmittance panel according to the present invention, and FIG. 8 is a schematic cross-sectional view of a display panel constituting the display device.

As shown in FIG. 7, the display device 200 includes a transparent display panel 300 and a variable transmittance panel 100 located on one side of the transparent display panel 300. The transparent display panel 300 includes a plurality of pixels, and each pixel includes a display portion 312, a driver 314, and a transparent portion 316. For example, the transparent portion 316 may occupy 40 to 60% of the total area of the display panel 300, but the present invention is not limited to this. The display unit 312 is driven by a voltage or signal supplied through the driver 314 to display an image. The transparent display panel 300 may be a liquid crystal panel or a light emitting diode panel.

The case where the transparent display panel 300 is a light emitting diode panel will be briefly described. Referring to FIG. 8 , which is a schematic cross-sectional view of the display panel shown in FIG. 7 , the transparent display panel 300 includes a third substrate 401 and a fourth substrate 402 facing each other, and the third and fourth substrates 401 and 402 face each other. 4 A light emitting diode (D) is located between the substrates 401 and 402 as a display element.

Each of the third substrate 401 and the fourth substrate 402 may be made of glass or plastic. For example, each of the third substrate 401 and the fourth substrate 402 may be made of a plastic material such as PES, PAR, PEI, PPS, PI, PC, PET, PEN, TAC, and/or CAP.

A gate wire (not shown) and a data wire (not shown) that cross each other to define the pixel area (P) are formed on the third substrate 401, and are parallel to the gate wire (not shown) or the data wire (not shown). Power wiring (not shown) is formed that is spaced apart from each other. The display unit 312, the driver 314, and the transparent part 316 are defined in each pixel area (P). A switching thin film transistor (not shown) is formed in each pixel area (P) at the intersection of the gate wire (not shown) and the data wire (not shown).

In addition, it is connected to a switching thin film transistor (not shown) and a power wiring (not shown), and a driving thin film transistor (DTr) is formed. The driving thin film transistor (DTr) includes a semiconductor layer 410, a gate electrode 420, and source and drain electrodes 431 and 433. The switching thin film transistor may have a similar structure to the driving thin film transistor (DTr).

The semiconductor layer 410 includes a channel region CR and a source region and drain regions SR and DR located on both sides of the channel region CR. This semiconductor layer 410 may be made of polycrystalline silicon or oxide semiconductor. Meanwhile, a buffer layer (not shown) that may be made of silicon oxide (SiO ₂ ) or silicon nitride (SiNx) may be formed between the semiconductor layer 410 and the third substrate 401 .

On the semiconductor layer 410, a gate insulating film 415 is formed. The gate insulating film 415 may be made of an inorganic insulating material such as silicon oxide (SiO ₂ ) or silicon nitride (SiNx). And, on the gate insulating film 415, a gate electrode 420 is formed corresponding to the channel region CR. The gate electrode 420 may be made of a low-resistance metal material such as copper or aluminum.

On the gate electrode 420, an interlayer insulating film 425 is formed. A semiconductor layer contact hole 435 exposing each of the source region SR and drain region DR of the semiconductor layer 410 may be formed in the gate insulating film 415 and the interlayer insulating film 425. The interlayer insulating film 425 may be made of an inorganic insulating material such as silicon oxide (SiO ₂ ) or silicon nitride (SiNx).

On the interlayer insulating film 425, source electrodes and drain electrodes 431 and 433 are formed. The source and drain electrodes 431 and 433 are in contact with the source and drain regions SR and DR of the semiconductor layer 410 through the corresponding semiconductor layer contact holes 435, respectively. The source and drain electrodes 431 and 433 may be made of the same material as the gate electrode 420.

A protective layer 440 may be formed on the source and drain electrodes 431 and 433. The protective layer 440 may be made of an inorganic insulating material such as silicon oxide (SiO ₂ ) or silicon nitride (SiNx), or an organic insulating material such as photoacrylic. A drain contact hole 441 exposing the drain electrode 433 is formed in the protective layer 440.

In Figure 8, the case where a driving thin film transistor (DTr) is formed using the semiconductor layer 410 made of crystalline silicon is explained as an example. In another embodiment, a driving thin film transistor with an inverted staggered structure using amorphous silicon as a semiconductor layer may be used. As another example, an oxide transistor using an oxide semiconductor may be used. Additionally, although not shown, a storage capacitor is formed in each pixel area (P).

The light emitting diode (D) is located on the protective layer 440 and is electrically connected to the driving thin film transistor (DTr) through the drain contact hole 441. The light emitting diode (D) may include first and second electrodes 451 and 453 and an organic light emitting layer 452 formed between the first and second electrodes 451 and 453.

Here, the first and second electrodes 451 and 453 are configured to have transparent characteristics. In this regard, the first and second electrodes 451 and 453 may be formed of a transparent conductive material. For example, one of oxide-based transparent conductive materials such as ITO, IZO, GZO, and IGZO may be used. At this time, one of the first and second electrodes 451 and 453 is an anode and the other is a cathode. The anode is made of a material with a relatively high work function value, and the cathode is made of a material with a relatively low work function value. The first electrode 451 is connected to the drain electrode 433 of the driving thin film transistor (DTr) through the drain contact hole 441 and is patterned in units of pixel areas (P). The second electrode 453 is formed integrally with the entire pixel area P of the display panel 300.

Meanwhile, a bank 460 having an opening may be formed in each pixel area (P) on the first electrode 451. Such a bank 460 serves to distinguish neighboring pixel areas (P). An organic light emitting layer 452 is formed in each pixel area P in response to the opening of the bank 460. The organic light emitting layer 452 functions to emit light by combining holes and electrons supplied from the first and second electrodes 451 and 453.

The organic light-emitting layer 452 may include a light-emitting material layer that substantially emits light. Meanwhile, to increase luminous efficiency, the organic light emitting layer 452 may have a multilayer structure. For example, the organic light emitting layer 453 may further include a hole injection layer, a hole transport layer, an electron injection layer, and an electron transport layer in addition to the light emitting material layer. The light emitting diode D having the above-described configuration generates light of corresponding brightness according to a signal applied to the gate electrode 420 of the driving thin film transistor DTr.

Additionally, the fourth substrate 402 is an encapsulation substrate and covers the driving thin film transistor (DTr) and the light emitting diode (D). A barrier layer 480 may be formed between the fourth substrate 402 and the light emitting diode (D) to prevent moisture, etc. from penetrating.

In FIG. 8, the area where driving elements such as the driving thin film transistor (DTr) are formed corresponds to the driving unit (314 in FIG. 7), and the area where the light emitting diode (D) is formed corresponds to the display unit (312 in FIG. 7). Meanwhile, no driving element or display element is formed in the transparent portion (316 in FIG. 7) and light is transmitted through the transparent portion (316 in FIG. 7). Additionally, the display unit 312 and the driving unit 314 may be areas that overlap with each other.

Referring again to FIG. 7, the variable transmittance panel 100 includes first and second substrates 110 and 120 facing each other, a first transparent electrode 130 located on the first substrate 110, and The second transparent electrode 140 located on the second substrate 120, and the electrochromic particles 160, electrolyte 170, and reflective metal cations located between the first and second substrates 110 and 120 ( An electrochromic layer 150 including 180) and a counter electrode located between the electrochromic layer 150 and the second transparent electrode 140 to facilitate the oxidation-reduction reaction in the electrochromic layer 150. 190).

The first substrate 110 and the second substrate 120 may be made of glass or plastic, respectively. For example, each of the first substrate 110 and the second substrate 120 may be made of a plastic material such as PES, PAR, PEI, PPS, PI, PC, PET, PEN, TAC, and/or CAP.

7 and 8, the first substrate 110 of the variable transmittance panel 100 and the fourth substrate 402 of the display panel 300 are shown to have the same configuration, but different substrates are used and they are attached. The variable transmittance panel 100 and the display panel 300 may be stacked. Each of the first transparent electrode 130 and the second transparent electrode 140 is made of a transparent conductive material.

The electrochromic layer 150 is located between the first and second transparent electrodes 130 and 140 and includes electrochromic particles 160, electrolyte 170, and reflective metal cations 180. Electrochromic particles 160 may have a core-shell structure. For example, the electrochromic particles 160 include an electrochromic material that changes color to black or the like by a reduction reaction. The electrolyte 170 that can form the electrochromic layer 150 is a gel-type or polymer-based electrolyte containing a dissolved lithium salt. Preferably, the medium constituting the electrolyte 170 can be heat-cured or photo-cured and may be made of a solid state electrolyte (SSE) that has relatively low electrical conductivity and excellent ionic conductivity.

Reflective metal cations 180 may be generated when metal salts such as chloride, sulfate, nitrate, and carbonate of reflective metals such as silver (Ag), aluminum (Al), copper (Cu), and palladium (Pd) are dissociated. The reflective metal cations 180 move toward the first and second transparent electrodes 130 and 140 depending on the intensity of the voltage applied to the variable transmittance panel 100. Due to the color change of the electrochromic particles 160 and the movement of the reflective metal cation 180 according to the intensity of the voltage applied to the permeability variable panel 100, the permeability variable panel 100 operates in a light-shielding mode (black mode) and a transmission mode. Various display modes can be implemented, such as transparent mode (transparent mode) and reflection mode (mirror mode).

Meanwhile, the counter electrode 190 may be made of an electron-accepting material such as metal oxide, conductive polymer, and/or metallocene-based single molecule or polymer.

The transmittance variable panel 100 of this configuration implements various display modes by applying voltage. For example, when a negative (-) voltage is applied to the first transparent electrode 130 and a positive (+) voltage is applied to the second transparent electrode 140 (when the first voltage is applied), electricity A light blocking mode can be implemented by color variation of the discolored particles 160 and movement of the reflective metal cations 180 to the first transparent electrode 130 (see FIG. 4). In addition, when no voltage is applied to the first and second transparent electrodes 130 and 140, the electrochromic particles 160 are oxidized, and the reflective metal cations 180 are uniformly dispersed in the electrolyte 170, thereby maintaining the transmission mode. is implemented (see Figure 5). On the other hand, when a positive (+) voltage is applied to the first transparent electrode 130 and a negative (-) voltage is applied to the second transparent electrode 140 (when the second voltage is applied), the reflective The metal cations 180 move toward the second transparent electrode 140 and function as a reflection electrode, implementing a reflection mode (see FIG. 6).

For example, when no voltage is applied to the first and second transparent electrodes 130 and 140, the transmittance variable panel 100 is in a light transmission mode, and light from the transparent portion 316 is transmitted. On the other hand, when the first voltage is applied to the first and second transparent electrodes 130 and 140, the shell 164 (see FIGS. 2 and 3) of the electrochromic particles 160 turns black, thereby creating a variable transmittance panel ( 100) goes into shading mode and blocks light. Therefore, the display device 200 including the variable transmittance panel 100 is used as a so-called transparent display device. Conversely, when the second voltage is applied to the first and second transparent electrodes 130 and 140, the reflective metal cation 180 functions as a reflective electrode and reflects light. Accordingly, the display device 200 including the variable transmittance panel 100 can be used as a so-called reflective display device.

As described above, the variable transmittance panel 100 constituting the display device 200 of the present invention can smoothly implement various display modes depending on the intensity of the applied voltage. By adjusting the applied voltage, it can be quickly switched to multiple display modes such as transmission mode, light blocking mode, and reflection mode. When implementing reflection mode, if visibility of the image to be displayed on the display device is a problem, the applied voltage is adjusted and switched to shading mode, etc. to prevent the background image from being displayed overlapping on the display device. It is possible to prevent the visibility of the image to be displayed from being reduced.

Hereinafter, the present invention will be described in more detail through exemplary embodiments, but the present invention is not limited to the technical ideas described in the following examples.

Example 1: Fabrication of unit electrochromic device as a variable transmittance panel

The composition of a 2-inch-sized single device is as follows. The electrochromic layer is Vio2+/TiO ₂ (viologen modified high-surface area TiO ₂ electrodes; electrochromic material used is 1-ethyl-1'-(2-phosphonoethyl)-4,4'-bipyridinium dichloride) studied by the Vlachopoulos group. was used, and was formed to a thickness of 4~6 ㎛ by spin-coating. SnO ₂ was used as a counter electrode and was laminated to a thickness of 300 to 800 nm, followed by heat sintering at 300°C to achieve high colorant efficiency (Electrochimica Acta vol. 53, p. 4065, 2008). The electrolyte composition is as follows. PEG[Mw. 200, 400, H(OCH ₂ -CH ₂ ) _n OH, Aldrich] 20 g of hexamethylene diisocyanate (HMDI) was stirred into 10 g and reacted at 60-70°C for 1 hour.

After this, caprolactone-modified hydroxyethyl acrylate (FA2D) [Mw. 20 g of 344 CH ₂ CHCOOCH ₂ CH2O (CO-(CH ₂ ) _5O ) ₂ H, Daicel Chemical Indus-tries) was reacted at 60-70°C for 0.5 hour, and then stirred at 80-90°C for 3 hours. After polyureathane acraylate was synthesized through the above reaction, 120 g and 0.2 g of 1M LiCF ₃ SO ₃ /Acetonitrile (ACN) solution and Irgacure 184, respectively, were added and stirred at room temperature for 2 hours. The electrolyte can be polymerized by photocuring and used as a gel polymer electrolyte. To add AgNO ₃ as a reflective material inside the electrolyte, 3.7 g of 30 wt% AgNO ₃ /Acetonitrile solution (AgNO ₃ content of 0.5 wt% in the total electrolyte) is added. was added and stirred at room temperature for 2 hours to prepare an electrolyte.

The electrode film used ITO/PET with a sheet resistance of 25 Ω/sq and a transmittance of 84%, and the cell gap was set to about 500 ㎛ to produce a unit electrochromic device as a variable transmittance panel.

Example 2: Fabrication of unit electrochromic device as a variable transmittance panel

A unit electrochromic device was manufactured by repeating the procedure of Example 1, except that 7.4 g of 30 wt% AgNO ₃ /Acetonitrile solution was used so that the content of undissociated AgNO ₃ in the electrolyte was 0.9 wt%.

Example 3: Fabrication of unit electrochromic device as a variable transmittance panel

A unit electrochromic device was manufactured by repeating the procedure of Example 1, except that 14.8 g of 30 wt% AgNO ₃ /Acetonitrile solution was used so that the content of undissociated AgNO ₃ in the electrolyte was 1.8 wt%.

Example 4: Fabrication of unit electrochromic device as a variable transmittance panel

A unit electrochromic device was manufactured by repeating the procedure of Example 1, except that 22.2 g of a 30 wt% AgNO ₃ /Acetonitrile solution was used so that the content of undissociated AgNO ₃ in the electrolyte was 2.6 wt%.

Comparative example: Fabrication of a unit electrochromic device as a variable transmittance panel

An electrochromic device containing no reflective metal salt in the electrolyte was manufactured. The electrochromic particles, counter electrode, electrode, and substrate constituting the electrochromic layer were used in the same manner as in Example 1, and the electrolyte composition was as follows.

Electrolytes are Methoxy poly(ethylene glycol) 1000 monomethacrylate (MPEGM), poly(ethyleneglycol)dimethylether(PEGDMe), Triallyl-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione (TATT) ), a photocurable gel polymer matrix composed of Irgacure 784 was used, and lithium trifluoromethanesulfate (LiCF ₃ SO ₃ ) was used as the salt to ensure thermal and operational stability (Journal of Nanoscience and Nanotechnology Vol. 10, p. 263, 2010).

Experimental Example 1: Evaluation of initial optical properties

The initial optical characteristics of the unit electrochromic devices manufactured in Examples 1 to 4 and Comparative Example were evaluated. To measure the transmittance, we used CA-210 (Minolta), a device that measures the luminance of light incident on the detector. After placing a backlight on the back to measure the transmittance, the light transmitted to each unit element and the unit Transmittance was calculated from the luminance of light transmitted when no device was present (for reference only). Using Zive SP2 (WonA Tech), the applied constant voltage was output uniformly for a certain period of time and connected to the unit device, and then the response time was measured with CA-210 used for transmittance. Reflectance was measured using CM5 (Konical Minolta).

After connecting each electrochromic element to the driving board configured as above, the voltage application conditions were written in sequence and the optical characteristics in the light blocking/transmitting/reflecting states were evaluated at a specific time after repeated driving. To implement shading mode, a voltage of 1.5V was applied for 11 seconds, to implement transparent mode, a voltage of -0.2V was applied for 17 seconds, and to implement reflection mode, a voltage of -1.1V was applied for 11 seconds. Approved.

The measurement results according to this experimental example are shown in Table 1 below. Meanwhile, Figure 9 is a graph showing the results of measuring the intensity of the driving voltage, transmittance, and reflectance over time for the unit electrochromic device manufactured in Example 2. By including AgNO ₃ provided as a source of reflective metal ions, a reflectance of approximately 80% was obtained from an initial reflectance of 7.8% (see FIG. 9), and it can be seen that the reflectance improved as the content of AgNO ₃ increased. On the other hand, it was confirmed that the electrochromic device manufactured in the comparative example had a low reflectance and could not be applied to reflection mode.

[Table 1]

Experimental Example 2: Evaluation of optical characteristics after 100 drives

The unit electrochromic devices manufactured in Examples 1 to 4 were driven in a light-shielding mode (+1.5V, 11 seconds), a transmission mode (-0.2V, 17 seconds), and a reflection mode (-1.1V, 11 seconds). After repeating the mode conversion cycle 100 times, the procedure of Experimental Example 1 was repeated to evaluate the optical properties. The evaluation results are shown in Table 2 below. The electrochromic device containing AgNO ₃ provided as a source of reflective metal ions maintained relatively good transmittance and reflectance even after 100 operations. In particular, when the AgNO ₃ content was 0.5 wt% or 0.9 wt%, there was almost no change in reflectance. It was confirmed that it was maintained without any.

[Table 2]

Example 5: Fabrication of unit electrochromic device as a variable transmittance panel

A unit electrochromic device was manufactured by repeating the procedure of Example 2, except that the size of the unit electrochromic device was 1 cm2 (1 x 1 cm).

Example 6: Fabrication of unit electrochromic device as a variable transmittance panel

A unit electrochromic device was manufactured by repeating the procedure of Example 2, except that the size of the unit electrochromic device was changed to 9 cm2 (3 x 3 cm).

Example 7: Fabrication of unit electrochromic device as a variable transmittance panel

A unit electrochromic device was manufactured by repeating the procedure of Example 2, except that the size of the unit electrochromic device was changed to 25 cm2 (5 x 5 cm).

Experimental Example 3: Evaluation of optical properties of electrochromic device

The optical properties were evaluated by repeating the procedure of Experimental Example 1 for the unit electrochromic devices manufactured in Examples 5 and 6, respectively. The evaluation results are shown in Table 3 below. Although the reflectance decreased as the size of the electrode constituting the unit element increased, it still showed good transmittance and reflectance. Figure 10 is a photograph of the reflection board of the unit electrochromic device manufactured in Example 6. It was inferred that as the area of the unit element decreases, the area occupied by the edge increases compared to the total area of the electrode, and as the size of the electric field at the electrode edge increases, the Ag ⁺ concentration becomes denser on the upper electrode surface, increasing the reflectance.

[Table 3]

Although the present invention has been described above based on exemplary embodiments and examples of the present invention, the present invention is not limited to the technical ideas described in the above embodiments and examples. Rather, those skilled in the art to which the present invention pertains will be able to easily make various modifications and changes based on the above-described embodiments and examples. However, it is clear from the appended claims that all such modifications and changes fall within the scope of rights of the present invention.

100: variable transmittance panel 110: first substrate
120: second substrate 130: first transparent electrode
140: second transparent electrode 150: electrochromic layer
160, 160A, 160B: Electrochromic particles
162, 162a, 162b: core 164: shell
170: Electrolyte 180: Metal cation
190: Counter electrode
200: display device 300: display panel

Claims (13)

first and second substrates facing each other;
a first transparent electrode located on the first substrate;
a second transparent electrode located on the second substrate; and
Comprising an electrochromic layer located between the first transparent electrode and the second transparent electrode,
The electrochromic layer includes electrochromic particles, an electrolyte that mediates an oxidation-reduction reaction of the electrochromic particles, and reflective metal cations,
The electrochromic particles are reduced at a first voltage of +1.0 to +3 V with respect to the second transparent electrode, and the reflective metal cations are reduced at a second voltage of -1.0 to -1.3 V with respect to the second transparent electrode. Transmittance variable panel moving from to the second transparent electrode.
According to clause 1,
The reflective metal cation is a variable transmittance panel including a reflective metal cation of silver (Ag), aluminum (Al), copper (Cu), or palladium (Pd).
According to clause 2,
The metal salt that dissociates into the reflective metal cation is any one selected from the group consisting of silver nitrate (AgNO ₃ ), silver chloride (AgCl), silver sulfate (Ag ₂ SO ₄ ), silver carbonate (Ag ₂ CO ₃ ), and combinations thereof. A variable transmittance panel that is a compound of .
According to clause 2,
A variable permeability panel wherein the metal salt that dissociates into the reflective metal cation is included in the electrolyte at a ratio of 0.1 to 5% by weight.
According to clause 1,
The electrochromic particles are a variable permeability panel that changes color by a reduction reaction.
According to clause 1,
When the first voltage is applied, the reflective metal cation moves to the first transparent electrode.
According to clause 1,
The metal salt that dissociates into the reflective metal cation is chloride of the reflective metal, sulfate of the reflective metal, nitrate of the reflective metal, or carbonate of the reflective metal.
According to clause 1,
The electrochromic particles are a variable transmittance panel consisting of a core and a shell.
According to clause 8,
The shell is a variable permeability panel made of a viologen-based compound.
According to clause 1,
A variable transmittance panel further comprising a counter electrode located between the second transparent electrode and the electrochromic layer and promoting an oxidation-reduction reaction in the electrochromic layer.
The variable transmittance panel according to any one of claims 1 to 10; and
A display panel located on one side of the variable transmittance panel and including a display portion and a transparent portion.
A display device including a. According to clause 1,
The electrochromic particles are a variable transmittance panel consisting of a first core, a second core surrounding the first core, and a shell surrounding the second core.
According to clause 12,
The first core includes a conductive metal oxide, the second core includes a non-conductive metal oxide, and the shell includes a metal oxide, a conductive polymer, or a viologen-based compound.