KR102620140B1 - Reflective display device - Google Patents

Abstract

The present invention relates to a reflective display device in which a color filter layer is composed of core particles, shell particles surrounding the core in a cluster shape, and nanoparticles containing a colorant selectively adsorbed on the surface of the shell particles. Adopting the nanoparticles according to the present invention improves reflectance and color gamut, and it is possible to implement a reflective display device that has a simple structure and does not require a separate external power source, ensuring process reproducibility and reliability.

Description

Reflective display device {REFLECTIVE DISPLAY DEVICE}

The present invention relates to a display device, and more specifically to a reflective display device having excellent reflectance and color gamut.

As the information society develops, the demand for display devices for displaying images is rapidly increasing. Reflecting these demands, flat panel displays such as liquid crystal displays (LCD) and organic light emitting diode (OLED) displays are being widely used.

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 employing an electrophoresis method, a method using electrochromic particles, etc. is known. Figure 1 is a cross-sectional view schematically showing the structure of a conventional reflective display device using an electrophoresis method to explain the driving principle of the display device.

As shown in FIG. 1, the electrophoretic display device 10 includes upper and lower substrates 11 and 12, and an ink layer 30 interposed between the upper and lower substrates 11 and 12. The ink layer 30 includes a plurality of capsules 40 filled with a plurality of charged black particles 42 and white particles 44.

On the lower substrate 11, a plurality of pixel electrodes 50 connected to a plurality of thin film transistors (not shown) are formed for each pixel area (not shown), and the plurality of pixel electrodes 50 selectively apply a (+) voltage. Or (-) voltage is applied. When a voltage of (+) polarity or (-) polarity is applied to the ink layer 30 through the plurality of pixel electrodes 50, the charged white and black particles 42 and 44 are moved to the top or bottom by the Coulomb force. Move to the bottom. At this time, when the black particles 42 move upward, a black mode is implemented, and when the white particles 44 move upward, a white mode can be implemented to display the image.

In the electrophoretic display device 10, the charged particles 42 and 44 tend to move downward according to the direction of gravity, so not only are the bistable characteristics of the charged particles 42 and 44 low, but the driving The voltage is high, over 15V, which is detrimental to power consumption. Additionally, since it can only display black and white, it cannot reproduce a variety of colors, and a color filter layer (not shown) is required to implement color.

In the electrophoretic reflective display device 10, a thin film transistor (not shown) is formed on the lower substrate 11 to implement color, and a red, green, and blue color filter is formed on the upper substrate 12. A color filter layer (not shown) is formed, and a common electrode (not shown) made of a transparent conductive material is formed under the color filter layer (not shown).

The electrophoretic display device 10 having this configuration uses external light such as natural light or indoor light as a light source, and has a pixel that selectively receives positive or negative polarity by a thin film transistor (not shown). The electrode 50 induces a change in the position of the plurality of black particles 42 and white particles 44 filled inside the capsule 40, and the light reflected from the capsule 40 passes through a color filter layer (not shown). By doing so, color images are realized.

However, as the color image is implemented by the capsule 40 and the color filter layer (not shown) containing black particles 42 and white particles 44 having different charges, the reflectance is low and there is a limit to improving the color reproduction rate. There is a problem. To explain this in more detail, when a voltage of (+) polarity or (-) polarity is applied, a large number of black particles 42 or white particles 44 may move positions and aggregate, so that the charged particles When (42, 44) aggregates, the response speed to voltage application slows down, reflection does not occur uniformly, and the contrast ratio decreases accordingly. In addition, a color filter layer (not shown) for implementing color is located on the upper substrate 12, and some of the light is absorbed or scattered by the color filter layer (not shown), thereby lowering reflectance and color gamut.

The purpose of the present invention is to provide a reflective display device that has excellent reflection characteristics and color gamut and can display various colors even without applying a separate external voltage.

Another object of the present invention is to provide a reflective display device that implements various colors other than black and white, but is structurally simple and has excellent process reliability and process reproducibility.

In the present invention, shell particles having a second size smaller than the first size are bonded to the surface of a core particle having a first size in the form of a cluster, and nanoparticles with a colorant selectively adsorbed on the surface of the shell particles are formed on a color filter layer. Provides a reflective display device constituting a.

The core particles may have an average particle size of sufficient size to reflect external light sources, e.g., 100 to 500 nm, and the shell particles may have an average particle size of 1 to 50 nm, allowing to increase the surface area of the nanoparticles. .

At this time, the core particles and the shell particles may be inorganic particles such as metal or non-metal oxides or fluorides. In an exemplary embodiment, nanoparticles having a refractive index of the core particle of 2.0 or more and a refractive index of the shell particle of less than 2.0 can be used. there is.

Depending on the type of colorant adsorbed on the shell particles, various color modes such as red color mode, green color mode, and blue color mode can be realized, and black mode can be achieved through oxidation and reduction reactions of electrochromic materials located independently of the color filter layer. and white mode can also be implemented.

In the present invention, shell particles with a smaller size than the core particles surround the surface of the core particles in the form of a cluster, and a reflective display device using nanoparticles with colorants of various colors selectively adsorbed on the surface of the shell particles as a color filter layer. suggests.

By adopting relatively large core particles, the reflectance of light can be improved, thereby expanding the viewing angle and ensuring high brightness. In addition, the nanoparticles constituting the color filter layer of the present invention have shell particles having a smaller size than the core particles clustered to the core particles, which can greatly increase the surface area of the nanoparticles. Since a large amount of colorant can be adsorbed on the surface of shell particles with a large surface area, color reproduction rate can be improved.

In addition, since the reflective display device of the present invention does not require a separate external power source and is structurally simple, the reliability and reproducibility of the process of manufacturing the reflective display device can be improved.

Figure 1 is a cross-sectional view schematically showing a reflective display device using a conventional electrophoresis method.
Figure 2 is a diagram schematically showing nanoparticles that can be applied to a color filter layer with improved reflectance and color gamut according to an exemplary embodiment of the present invention. It shows a nanoparticle in which shell particles are bonded in a cluster form to the surface of the core particle.
Figure 3 is a diagram schematically showing nanoparticles that can be applied to a color filter layer with improved reflectance and color gamut according to another exemplary embodiment of the present invention. It shows nanoparticles with a colorant adsorbed on shell particles bonded in a cluster form to the surface of the core particle.
4A and 4B are schematic diagrams for explaining the difference in reflectance depending on the difference in refractive index between core particles and shell particles according to an exemplary embodiment of the present invention.
Figure 5 is a cross-sectional view schematically showing a reflective display device in which nanoparticles are applied to the color filter layer according to the first exemplary embodiment of the present invention.
6A and 6B are schematic diagrams schematically illustrating a state in which the color of an electrochromic material included in a reflective display device according to an exemplary embodiment of the present invention changes depending on whether or not power is applied.
7A to 7E are diagrams showing various image modes implemented in a reflective display device in which nanoparticles are applied to the color filter layer, respectively, according to an exemplary embodiment of the present invention. For convenience of explanation, the thin film transistor structure is omitted.
FIG. 8 is a cross-sectional view schematically showing a reflective display device in which nanoparticles are applied to a color filter layer according to a second exemplary embodiment of the present invention.
9A to 9E are diagrams showing various image modes implemented in a reflective display device in which nanoparticles are applied to a color filter layer according to an exemplary embodiment of the present invention, respectively. For convenience of explanation, the thin film transistor structure is omitted.
FIG. 10 is a cross-sectional view schematically showing a reflective display device in which nanoparticles are applied to a color filter layer according to a third exemplary embodiment of the present invention.
Figure 11 is a graph showing the results of measuring the reflectance and surface area of white nanoparticles synthesized according to an exemplary embodiment of the present invention. The bottom percentages represent the fraction of core particles in nanoparticles.
Figure 12 is a graph showing the results of simulated measurement of reflectance and color gamut in a reflective display device in which nanoparticles synthesized according to an exemplary embodiment of the present invention are applied to the color filter layer. The bottom percentages represent the fraction of core particles in nanoparticles.

The color filter of a reflective display device requires excellent reflection characteristics and good color gamut. The present invention relates to a reflective display device applied with a color filter layer composed of nanoparticles capable of realizing excellent reflection characteristics and color gamut. Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings where necessary.

[Nanoparticles]

[First Embodiment]

Figure 2 is a diagram schematically showing nanoparticles according to a first exemplary embodiment of the present invention. As shown in FIG. 2, the nanoparticle 100 according to the first embodiment of the present invention includes a core particle 110 having a first size, a second size smaller than the first size, and a core particle 110 having a first size. It includes a plurality of shell particles 120 that surround and join (110) in a cluster form.

The color filter of a reflective display device must have a large surface area to implement a high color gamut and must have good reflection characteristics to ensure high luminance. When large-sized single crystal particles are used to ensure high reflectance, the surface area of the particles is low (approximately 8.8 ㎡), so the amount of colorant adsorbed on the large single crystal particles is reduced, resulting in lower color gamut. gamut) is lowered. On the other hand, when small-sized single crystal particles with a large surface area are used to improve color reproduction, there is a problem in that the transmittance becomes too high and the reflectance decreases. Accordingly, in the present invention, nanoparticles 100, in which relatively small shell particles 120 are bonded to the surface of relatively large core particles 110 in a cluster form, are used to secure reflectivity and at the same time provide good reflectivity. Color gamut can be implemented.

The core particles 110 serve as a reflector that reflects light when an external light source (outside light) such as natural light or indoor light is incident on the reflective display device (200, 300, 400, see FIGS. 5, 8, and 10). Perform. Core particles 110 have a first size sufficient to reflect light. In an exemplary embodiment, core particles 110 may have an average particle size of 100 to 500 nm, preferably 200 to 300 nm.

Meanwhile, the shell particles 120 are bonded to the surface of the core particles 110 in a cluster form to increase the total surface area of the nanoparticles 100. Shell particles 120 have a second size sufficient to increase the total surface area of nanoparticles 100. In an exemplary embodiment, shell particles 120 may have an average particle size of 1 to 50 nm, preferably 10 to 20 nm.

The core particles 110 and shell particles 120 constituting the nanoparticles 100 according to the first embodiment may be white inorganic particles. In exemplary embodiments, core particles 110 and shell particles 120 may be metal or non-metal oxides or fluorides. Specifically, the core particles 110 and the shell particles 120 are each made of aluminum oxide (Al ₂ O ₃ ), zirconium oxide (ZrO ₂ ), and titanium dioxide (TiO ₂ ), for example, the crystal phase is anatase or rutile. (rutile) oxide particles such as titanium dioxide, zinc oxide (ZnO), silica (SiO ₂ ), tin oxide (SnO ₂ ) and/or barium fluoride (BaF ₂ ), calcium fluoride (CaF ₂ ), magnesium fluoride ( It may be made of a material selected from the group consisting of fluoride particles such as MgF ₂ ) and combinations thereof.

In an exemplary embodiment, core particles 110 and shell particles 120 may be blended in a weight ratio of 1:1 to 5:1. When the weight ratio of the core particles 110 and the shell particles 120 is in the range of 1:1 to 5:1, the reflectance is improved by the core particles 110 having a relatively large size and the relatively small size It is possible to implement all improvements in color gamut due to the increase in surface area by the shell particles 120.

The reflectance of external light can be improved by applying relatively large core particles 110, and the surface area of the nanoparticles 100 can be increased by applying relatively small shell particles 120.

[Second Embodiment]

Meanwhile, the nanoparticles of the present invention may further include a colorant adsorbed on the shell particles 120 in addition to the core particles 110 and the shell particles 120. Figure 3 is a diagram schematically showing nanoparticles according to another exemplary embodiment of the present invention. As shown in FIG. 3, the nanoparticles 100A according to another exemplary embodiment of the present invention include a core particle 110 having a first size and a first particle bonded to the surface of the core particle 110 in a cluster form. It includes shell particles 120 having a size of 2 and a colorant 130 adsorbed on the shell particles 120.

Like the nanoparticles 100 shown in FIG. 2, the core particles 110 constituting the nanoparticles 100A according to the second embodiment of the present invention serve as a reflector to reflect incident light, and 100 It may have an average particle size of from 500 nm to 500 nm, preferably from 200 to 300 nm. Meanwhile, the shell particles 120 are bonded to the surface of the core particles 110 in a cluster form to increase the total surface area of the nanoparticles 100. The shell particles 120 may have an average particle size of 1 to 50 nm, preferably 10 to 20 nm. Since a large amount of the colorant 130 can be adsorbed to the relatively small-sized shell particles 120, the color reproduction rate can be improved.

The colorant 130 may be any colorant that can be adsorbed on the surface of the shell particles 120 constituting the nanoparticles 100A. In one exemplary embodiment, colorant 130 may be a red colorant, a green colorant, or a blue colorant. In another alternative embodiment, colorant 130 may be a cyan/magenta/yellow colorant instead of a red/green/blue colorant.

When the core particles 110 and shell particles 120 constituting the nanoparticles 100A of the present invention are inorganic particles, a dye that can be efficiently adsorbed on the surface of the shell particles 120 is used as the colorant 130. It can be used as For example, the dye may be an organic dye having a functional group that can be adsorbed to the surface of the shell particle 120, preferably an anionic or anion-forming organic dye.

In one exemplary embodiment, the colorant 130 has a hydroxyl group (-OH), a carboxylic acid group (-COOH), a phosphonic acid group (-PO ₃ H), a sulfonic acid group (-SO ₃ H), and a ketoaldehyde in the molecule. It may be an organic dye having a functional group selected from the group consisting of groups (-CO-COH), combinations thereof, and salts thereof (for example, sodium sulfonate salt). When an organic dye having the above-described functional group is used as the colorant 130, the shell particle 120 preferably has a surface capable of reacting with the above-mentioned functional group. In this case, the shell particle 120 is a metal or non-metal oxide, such as aluminum oxide (Al ₂ O ₃ ), zirconium oxide (ZrO ₂ ), titanium dioxide (TiO ₂ ), zinc oxide (ZnO), silica (SiO ₂ ), tin oxide (SnO ₂ ), and combinations thereof.

More specifically, in the molecule there is a hydroxyl group (-OH), a carboxylic group (-COOH), a phosphonic acid group (-PO ₃ H), a sulfonic acid group (-SO ₃ H), a ketoaldehyde group (-CO-COH), ) The following can be used as organic dyes having functional groups such as , combinations thereof, and salts thereof.

Red organic dyes include C.I. C.I. Mordant Red 3, C.I. Mordant Red 7, C.I. Mordaunt Red 11, C.I. Mordant Red 15, C.I. Mordaunt Red 19, C.I. Mordaunt Red 30, D&C Red 34, C.I. Acid Red 1 (C.I. Acid Red 1), C.I. Acid Red 13, C.I. Acid Red 14, C.I. Acid Red 32, C.I. Acid Red 37, C.I. Acid Red 38, C.I. Acid Red 42, C.I. Acid Red 88, C.I. Acid Red 119, C.I. Acid Red 131, C.I. Acid Red 138, C.I. Acid Red 154, C.I. Acid Red 249, C.I. Acid Red 299, C.I. Reactive Red 8 (C.I. Reactive Red 8), C.I. Reactive Red 12, C.I. Reactive Red 23, C.I. Direct Red 23 (C.I. Direct Red 23), C.I. Direct Red 75, C.I. Direct Red 76, C.I. Direct Red 79, C.I. Direct Red 80, C.I. Direct Red 81, C.I. Direct Red 250, etc. can be used.

Green organic dyes include C.I. Mordaunt Green 21, C.I. Mordaunt Green 23, C.I. Mordaunt Green 31, C.I. Acid Green 25, C.I Acid Green 41, C.I. Acid Green 50, C.I. Direct Green 1, C.I. Direct Green 21, C.I. Direct Green 26, etc. can be used.

Blue organic dyes include C.I. Mordaunt Blue 1, C.I. Modern Blue 3, C.I. Mordant Blue 7, C.I. Mordant Blue 9, C.I. Mordant Blue 10, C.I. Mordant Blue 13, C.I. Mordant Blue 29, C.I. Acid Blue 9, C.I. Acid Blue 25, C.I. Acid Blue 40, C.I. Acid Blue 43, C.I. Acid Blue 62, C.I. Acid Blue 92, C.I. Acid Blue 113, C.I. Acid Blue 117, C.I. Acid Blue 129, C.I. Reactive Blue 15, C.I. Reactive Blue 19, C.I. Reactive Blue 216, C.I. Direct Blue 15, C.I. Direct Blue 78, C.I. Direct Blue 86, C.I. Direct Blue 93, C.I. Direct Blue 106, etc. can be used.

Nanoparticles (100A) according to the second embodiment of the present invention have excellent reflection characteristics by using core particles (110) having the first size. In addition, since the shell particles 120 having the second size are joined to the surface of the core particles 110 in clusters, the surface area is greatly increased. Because a large amount of the colorant 130 can be adsorbed on the surface of the shell particle 120 with an increased surface area, color gamut can be improved when an external light source is reflected from the nanoparticle 100A.

Meanwhile, the nanoparticles (100, 100A) according to the present invention are used in the color filter layers (260, 360, 460, FIGS. 5, 8 and 10) can be configured. At this time, it is necessary to adjust the refractive index of the core particles 110 and shell particles 120 constituting the nanoparticles 100 and 100A in relation to the reflection of light incident on the reflective display device. According to the Fresnel Equation shown in Equation 1 below, the reflectance (R) between two media with different refractive indices (n ₁ , n ₂ ) increases as the difference in refractive index between the two media increases.

Equation 1

Therefore, as shown in FIG. 4A, when the refractive index (n ₁ ) of the shell particle 120 and the refractive index (n ₂ ) of the core particle 110 are approximately the same, between the core particle 110 and the shell particle 120 Diffuse reflection occurs on the surface of Accordingly, most of the light incident on the nanoparticles (100, 100A, see FIGS. 2 and 3) is diffusely reflected and only a portion is reflected in the direction in which the light was incident, which may deteriorate the overall reflection characteristics.

On the other hand, as shown in Figure 4b, when the refractive index (n ₁ ) of the shell particle 120 and the refractive index (n ₂ ) of the core particle 110 are significantly different, the nanoparticles 100, 100A, Figures 2 and 3), most of the incident light is regularly reflected toward external light, which is the direction from which the light was incident, improving reflection characteristics.

Therefore, according to an exemplary embodiment of the present invention, the refractive index (n ₁ ) of the shell particles 120 constituting the nanoparticles (100, 100A, see FIGS. 2 and 3) and the refractive index (n ₂ ) of the core particles 110 The larger the difference, the better the reflection characteristics. In a preferred embodiment, the difference between the refractive index (n ₁ ) of the shell particle 120 and the refractive index (n ₂ ) of the core particle 110 may be 0.5 or more, for example, 0.5 to 2.0.

At this time, in one exemplary embodiment, the refractive index (n ₁ ) of the shell particle 120 may be greater than the refractive index (n ₂ ) of the core particle 110. In another example embodiment, the refractive index (n ₂ ) of the core particle 110 may be greater than the refractive index (n ₁ ) of the shell particle 120. For example, according to an exemplary embodiment of the present invention, the refractive index (n ₂ ) of the core particle 110 is greater than the refractive index (n ₁ ) of the shell particle 120. For example, the refractive index (n ₂ ) of the core particles 110 may be 2.0 to 3.5, and the refractive index (n ₁ ) of the shell particles 120 may be 1.3 or more and less than 2.0.

In one exemplary embodiment, zirconium dioxide having a relatively high refractive index (refractive index 2.208), titanium dioxide, such as titanium dioxide on rutile crystals (refractive index 2.874), titanium dioxide on anatase crystals (refractive index 2.493), zinc oxide ( It is preferable that inorganic particles selected from the group consisting of a refractive index of 2.0 and a combination thereof are used as a material for the core particles 110. On the other hand, aluminum oxide (refractive index 1.77), silica (refractive index 1.457), tin oxide (refractive index 1.475), barium fluoride (refractive index 1.455), calcium fluoride (refractive index 1.434), magnesium fluoride (refractive index 1.374) and these have relatively low refractive indices. It is preferable that inorganic particles selected from the group consisting of a combination of are used as a material for the shell particles 120.

[Reflective display device]

[First Embodiment]

As described above, the nanoparticles (100, 100A) according to the present invention have excellent reflection characteristics and color gamut, so they can be applied to the color filter layer of a reflective display device. Figure 5 is a cross-sectional view schematically showing a reflective display device divided into three pixel areas according to a first exemplary embodiment of the present invention.

As shown in FIG. 5, the reflective display device 200 according to the first embodiment of the present invention includes a first substrate 210, a second substrate 220 facing the first substrate 210, and a first substrate 220. The first electrode 230 located on the substrate 210, the second electrode 240 located on the second substrate 220, and the electrolyte located between the first electrode 210 and the second electrode 240. Layer 270, a variable light-shielding layer 280 containing electrochromic particles 282 located between the second electrode 240 and the electrolyte layer 270, between the first electrode 230 and the electrolyte layer 270. It includes a color filter layer 260 located at, and optionally includes a counter electrode 250 located between the first electrode 230 and the color filter layer 260.

The first substrate 210 and the second substrate 220, which constitute the lower and upper substrates of the reflective display device 200, may be glass substrates, thin flexible substrates, or polymer plastic substrates. At this time, the flexible substrate is one of polyethersulfone (PES), polyimide (PI), polyethylenenaphthalate (PEN), polyethyleneterephthalate (PET), and polycarbonate (PC). can be formed.

A first electrode 230 that can function as a reflector is located inside the first substrate 210, that is, on the first substrate 210. The reflective display device 200 according to the present invention can be used as a reflective display device that uses external light such as natural light or indoor light as a light source, and the light incident through the front of the second substrate 220 is transmitted to the first electrode. (230) It can be diffused, scattered, and reflected. By applying the first electrode 230 in this way, reflection characteristics are improved, and a high-brightness image can be implemented. For example, the first electrode 230 is a conductive metal with good reflectivity, such as gold (Ag), silver (Au), palladium (Pd), copper (Cu), aluminum (Al), mixtures thereof, and / Or it may be made of an alloy thereof.

In another alternative embodiment, the first electrode 230 is made of a transparent conductive material, such as indium-tin-oxide (ITO), indium-zinc-oxide (IZO) ), zinc-oxide (ZnO), and indium-oxide (In ₂ O ₃ ).

In another alternative embodiment, the first electrode 230 may have a multi-layer structure including a transparent conductive material and a conductive material with good reflective properties. For example, the first electrode 230 may have a triple-layer structure of an indium-tin-oxide (ITO) layer, an aluminum-palladium-copper (APC) alloy layer, and an ITO layer. The first electrode 230 may be deposited on the first substrate 210 through a sputtering process.

At this time, a thin film transistor (Tr) for driving each pixel area (PA1, PA2, PA3) is connected to the first electrode 230 and positioned. Specifically, on the first substrate 210, a gate wire (not shown) and a data wire (not shown) intersect to define each pixel area (PA, PA2, PA3), and the thin film transistor (Tr) is the gate wire. and connected to the data wiring. The thin film transistor (Tr) includes a gate electrode 211, a semiconductor layer 214, a source electrode 215, and a drain electrode 216. A gate insulating film 212 is positioned between the gate electrode 211 and the semiconductor layer 214. The gate insulating film 212 may be made of an inorganic insulating material such as silicon oxide (SiO ₂ ) or silicon nitride (SiNx).

The semiconductor layer 214 overlaps the gate electrode 211 and is made of an oxide semiconductor material. In contrast, the semiconductor layer 214 has a stacked structure of an active layer (not shown) made of pure amorphous silicon and an ohmic contact layer (not shown) made of impurity-doped amorphous silicon. It may be possible.

The source electrode 215 and the drain electrode 216 are spaced apart from each other and are located on the semiconductor layer 214. The gate electrode 211, source electrode 215, and drain electrode 216 may each be made of a low-resistance metal material such as aluminum or copper.

A protective layer 217 is formed that covers the thin film transistor (Tr) and has a drain contact hole 218 exposing the drain electrode 216. For example, the protective layer 217 may be made of an organic insulating material such as photoacrylic. Additionally, an insulating layer (not shown) made of an inorganic insulating material such as silicon oxide or silicon nitride may be further formed between the protective layer 217 and the source and drain electrodes 215 and 216.

The first electrode 230 is connected to the drain electrode 216 through the drain contact hole 218 and is formed on the protective layer 217.

Meanwhile, a counter electrode 250 may be positioned between the first electrode 230 and the color filter layer 260. The counter electrode 250 is used to supply insufficient ions to the electrolyte layer 270. In one exemplary embodiment, counter electrode 250 is made of cerium oxide (CeO ₂ ), titanium oxide (TiO ₂ ), tungsten oxide (WO ₃ ), nickel oxide (NiO), molybdenum oxide (MoO ₃ ), vanadium oxide. (V ₂ O ₅ ) and may be made of a metal oxide selected from the group consisting of combinations thereof. At this time, the counter electrode 250 can be formed by applying the dispersed solution of these metal oxides on the first electrode 230 and then drying and sintering. Optionally, the counter electrode 250 is deposited from the vapor phase of these metal oxides, for example, by depositing the first electrode by a method such as chemical vapor deposition (CVD) or physical vapor deposition (PVD). It can be laminated on (230).

In another exemplary embodiment, the counter electrode 250 is made of a metallocene compound such as poly(3,4-ethylenedioxythiophene (PEDOT)) or ferrocene. It may be made of a material selected from the group consisting of or derivatives, diphenylamine, triphenylamine, phenothiazine-based polymers, and/or phenoxazine-based polymers.

In one exemplary embodiment, the counter electrode 250 may be made of an acrylic terpolymer containing a metallocene moiety and triarylamine, as described in Korean Patent Publication No. 10-2016-0053352. Alternatively, the compound having a metallocene moiety that can form the counter electrode 250 may be a copolymer represented by Formula 1 below. When it is desired to form a compound having a metallocene moiety into the counter electrode 250, a method of coating this compound on the first electrode 230 and drying it may be adopted. The substances of Formula 1 may also include tertiary amine salts, such as triarylamine salts.

Formula 1

(In Formula 1, a and b are each natural numbers of 1 or more, and M is a transition metal that can be selected from the group consisting of transition metals, for example, Ti, V, Cr, Mn, Fe, Co, Ni, Ru, and Os. it is metal)

The counter electrode 250 may be formed to have a thickness of approximately 100 to 1000 nm. If the thickness of the counter electrode 250 is less than 100 nm, the driving characteristics of the electrolyte layer 270 may deteriorate, and if the thickness of the counter electrode 250 exceeds 100 nm, the response speed may decrease due to an increase in resistance. there is.

Meanwhile, the second electrode 240 is located inside the second substrate 220 facing the first substrate 210. The second electrode 240 is made of a transparent conductive material, for example, indium-tin-oxide (ITO), indium-zinc-oxide (IZO), zinc-oxide (ZnO). ) and indium-oxide (In ₂ O ₃ ).

The electrolyte layer 270 is located between the first electrode 230 and the second electrode 240, more specifically between the first electrode 230 and the variable light-shielding layer 280 made of electrochromic particles 282. For example, the electrolyte layer 270 may be made of a solid electrolyte. When a liquid electrolyte is used, there is a risk of leakage of the fluid electrolyte. For example, the electrolyte layer 270 is a gel-type or polymer-based electrolyte containing a dissolved lithium salt. Preferably, the medium of the electrolyte layer 270 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) (PVDF-HFP), Polyacrylonitrile (PAN), poly(methyl methacrylate) (PMMA), poly(2-acrylamido-2-methyl-1-propanesulfonic acid) acid, Poly-AMPS), modified polyethylene oxide (modified PEO), etc. can 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 can be used in the electrolyte layer 270 include, for example, lithium bis((trifluoromethyl)sulfonyl)amide (LiTf2N), lithium trifluoromethane sulfonate (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.

For example, the electrolyte layer 270 may be formed on the counter electrode 250 to have a thickness of 20 to 200 ㎛. If the thickness of the electrolyte layer 270 is less than 20 ㎛, the device driving characteristics of the reflective display device 200 may deteriorate, and local current may flow to the upper part of the second electrode 240, shortening the lifespan of the device. there is. Additionally, if the thickness of the electrolyte layer 270 exceeds 200 ㎛, the response speed of the device may slow and the electrolyte may spread to adjacent pixel areas.

Additionally, a variable light blocking layer 280 in which a plurality of electrochromic particles 282 are disposed is located on the second electrode 240. The electrochromic particles 282 that can be applied to the reflective display device 200 of the present invention may be any particles that can be converted to transparent and black through an oxidation-reduction reaction depending on whether or not power is applied. That is, the electrochromic particles 282 change their light transmission characteristics due to an electrical oxidation-reduction reaction and transmit or absorb external light to implement a light transmission mode or a light blocking mode. For example, the electrochromic particles 282 may be positioned in a widely dispersed manner within the electrolyte layer 270.

In one exemplary embodiment, electrochromic particles 282 may be inorganic particles having a core 282a-shell 282b structure as shown in FIGS. 6A-6B. The core 282a may use spherical or amorphous particles having an average particle size of 5 to 200 nm, preferably 10 to 100 nm. The core 282a may use a porous material to improve the discoloration characteristics occurring in the shell 282b.

In one exemplary embodiment, a conductive material may be used as the core 282a to improve charge mobility. Conductive materials include indium-tin-oxide (ITO), indium-zinc-oxide, antimony-tin-oxide (ATO), and fluorine-doped tin. -oxide (fluorine-doped tin-oxide, FTO), aluminum-zinc oxide (aluminum-zinc oxide, AZO), and combinations thereof.

In another exemplary embodiment, the core 282a may use a non-conductive metal oxide that exhibits excellent transmittance to visible light and has a large specific surface area. The non-conductive metal oxide with a large specific surface area may be selected from the group consisting of titanium oxide (TiO ₂ ), zinc oxide (ZnO), silica (SiO ₂ ), and combinations thereof.

That is, the core 282a may be selected from the group consisting of the above-described conductive metal oxide, non-conductive metal oxide, and combinations thereof. The core 282a is not limited to the above-described materials, and may be made of an organic material, an inorganic material, or a mixture of organic and inorganic materials with high transmittance to visible light and excellent conductivity.

The shell 282b is oxidized or reduced by the applied electrical signal, that is, the voltage applied by the first electrode 230 and the second electrode 240, and is in a transparent or ON state. It can be made of an electrochromic material that changes color reversibly to black (B/K) and transmits or absorbs light. For example, the shell 282b may be an organic compound having the following formula (2).

Formula 2

(In Formula 2, R ₁ and R ₂ are each independently a hydrogen atom, a halogen atom, a sulfur compound, a hydroxy group, a substituted or unsubstituted C1~C20 alkoxy group, a substituted or unsubstituted C1~C20 alkyl group, or a substituted or unsubstituted C2~C20 alkenyl group, substituted or unsubstituted C2~C20 alkynyl group, substituted or unsubstituted C3~C20 cycloalkyl group, substituted or unsubstituted C3~C20 cycloalkenyl group, substituted or unsubstituted C3~C20 cycloalkyl group. Alkynyl group, substituted or unsubstituted C2~C20 heterocycloalkyl group, substituted or unsubstituted C2~C20 heterocycloalkenyl group, substituted or unsubstituted C2~C20 heterocycloalkynyl group, substituted or unsubstituted C6~C30 It is selected from an aryl group, a substituted or unsubstituted C5~C30 heteroaryl group, a substituted or unsubstituted C6~C30 oxyaryl group, and a substituted or unsubstituted C5~C30 heterooxyaryl group, and R ₃ and R ₄ are each Independently _, it is _a hydrogen atom, a substituted or unsubstituted _C1 ~C5 alkyl group, and

In another exemplary embodiment, the electrochromic particles 282 do not have a core-shell structure and may be a material that reversibly changes color to black or transparent by an electrical signal. For example, the electrochromic particles 282 may be a material represented by the following formula (3).

Formula 3

When the shell 282b constituting the electrochromic particle 282 changes from black to transparent or from transparent to black, if the shell 282b is black, external light is blocked and a light blocking mode is implemented, and if the shell 282b is transparent, external light is blocked. Transmission mode can be implemented by transmitting. Let’s take a look at this.

As shown in FIG. 6A, when power is not applied to the first and second electrodes 230 and 240, that is, in the OFF state, the core 282a and shell 282b of the electrochromic particles 282 are All have a transparent state. As the electrochromic particles 282 change to a transparent state, external light passes through the variable light blocking layer 280 and is reflected by the color filter layer 260. By appropriately controlling the power of the variable light-shielding layer 280 in each pixel area (PA1, PA2, and PA3), various color modes and white modes can be implemented, which will be described later.

Meanwhile, as shown in Figure 6b, when power is applied to the first and second electrodes 230 and 240, that is, in the ON state, the shell 282b of the electrochromic particle 282 is converted to black. . Since external light is absorbed by the variable light blocking layer 280 made of electrochromic particles 282 discolored to black, the reflective display device 200 can implement a black image mode, which is a light blocking mode.

In one exemplary embodiment, the electrochromic particles 282 are coated on the second electrode 240 using a method such as dip coating, spin coating, roller coating, spray coating, bar coating, slit coating, etc. It can be. In another exemplary embodiment, the electrochromic particles 282 may be formed through a printing method such as screen printing, gravure printing, offset printing, or flexographic printing. In an exemplary embodiment, the variable light blocking layer 280 including electrochromic particles 282 may be formed on the two electrodes 240 to a thickness of 1 to 50 nm, preferably 1 to 10 nm.

Meanwhile, the color filter layer 260 may be positioned between the counter electrode 250 and the electrolyte layer 270. According to the first exemplary embodiment of the present invention, the color filter layer 260 includes a red color filter layer 260R, a green color filter layer 260G, and a blue color filter layer 260G in each pixel area (PA1, PA2, PA3). is achieving. At this time, a partition 202 is located at the border of these pixel areas (PA1, PA2, and PA3) between the first substrate 210 and the second substrate 220, so that each color filter layer (260R, 260G, 260B) Nanoparticles (100R, 100G, 100B) can be separated. If the positions of the nanoparticles (100R, 100G, and 100B) are fixed by the medium, the partition wall that isolates each nanoparticle (100R, 100G, and 100B) may be omitted. For example, the color filter layer 260 may be formed by patterning nanoparticles 100R, 100G, and 100B in each pixel area (PA1, PA2, and PA3) on the counter electrode 250.

Looking specifically, the color filter layer 260 is a nano particle (hereinafter referred to as , called 'red nanoparticles', a red color filter layer (260R) made of 100R), and a green colorant (130, A green color filter layer (260G) composed of nanoparticles (hereinafter referred to as 'green nanoparticles', 100G) adsorbed (see FIG. 3), and shell particles (120) clustered on the surface of the core particles (110, see FIG. 3). It consists of a blue color filter layer (260B) made of nanoparticles (hereinafter referred to as 'blue nanoparticles', 100B) to which a blue colorant (130, see FIG. 3) is adsorbed.

That is, the color filter layer 260 according to the present invention is composed of nanoparticles (100R, 100G) composed of a plurality of shell particles (120, see Figures 2 and 3) clustered to the core particle (110, see Figures 2 and 3). , 100B). According to the present invention, since the color filter layer 260 is composed of nano-sized nanoparticles (100R, 100G, and 100B), the electrolyte can penetrate between these nanoparticles (100R, 100G, and 100B).

According to an exemplary embodiment, nanoparticles (100, Whether 100A, 100R, 100G, 100B) was used in the color filter layer (260, 260R, 260G, 260B) can be checked in the following way. First, color can be confirmed by measuring color coordinates (Y, x, z), core-shell structure can be confirmed through transmission electron microscopy (TEM), and the ratio of core particles to shell particles can be determined by The size of the main peak according to the X-ray diffraction method (XRD) can be analyzed by evaluating the size of the main peak through Equation 2 below.

Equation 2

( _{In Equation 2 ,} signal intensity of ~28°), and l _shell is the signal intensity of the shell particle cluster-bonded to the core particle (for example, if the shell particle is TiO ₂ with an anatase crystal phase, the main peak of the anatase crystal phase (~25°) signal intensity), and n in front of it is the intensity correction factor of the shell particle, which is 3 if the shell particle is anatase)

As described above, the red nanoparticles (100R), green nanoparticles (100G), and blue nanoparticles (100B) have a plurality of shell particles (120, see Figure 3) on the surface of the core particle (110, see Figure 3). Clusters are joined. Both excellent reflection characteristics due to the size of the core particles (110, see Figures 2 and 3) and excellent color gamut due to the large surface area of the shell particles (120, see Figures 2 and 3) can be achieved. In particular, by appropriately controlling the power to the variable light-shielding layer 280 made of electrochromic particles 282, not only black mode and white mode, but also nanoparticles (see FIG. 3) on which different colorants (130, see FIG. 3) are adsorbed. Various color modes implemented in the color filter layers (260R, 260G, 260B) each composed of (100R, 100G, 100B) can be implemented, which will be described in more detail.

As shown in FIG. 7A, when it is desired to implement black mode in the reflective display device 200, the first and second electrodes 230 located in all of the first to third pixel areas (PA1, PA2, and PA3) Power is applied to 240 and finally an electrical signal is applied to the variable light blocking layer 280. Accordingly, the shell 282b (see FIG. 6B) of the electrochromic particles 282 constituting the variable light blocking layer 280 is discolored to black. As a result, the variable light blocking layer 280 is converted to the light blocking mode in the first to third pixel areas (PA1, PA2, and PA3).

At this time, when external light such as natural light or indoor light enters the reflective display device 200, the external light is transmitted to the variable light blocking layer 280 by electrochromic particles 282 in which the shell 282b (see FIG. 6b) is discolored to black. ) and is prevented from entering the color filter layers (260R, 260G, 260B) below. Accordingly, the reflective display device 200 can implement black mode.

Meanwhile, as shown in FIGS. 7B to 7E, when the reflective display device 200 wishes to implement a color mode, power is not applied only to the variable light-shielding layer 280 in the pixel area displaying a specific color. By not doing so, the variable light-shielding layer 280 implements the light transmission mode in the OFF state, and by applying power to the variable light-shielding layer 280 in the remaining pixel area, the remaining variable light-shielding layer 280 is turned ON. Implements the state's shading mode.

For example, as shown in FIG. 7B, when the reflective display device 200 implements a red color mode, the variable light-shielding layer 280 in the first pixel area PA1 corresponding to the red color filter layer 260R ) is set to OFF, so that the variable light-shielding layer 280 of the first pixel area PA1 implements a light transmission mode. By setting the switch of the variable light blocking layer 280 of the remaining pixel areas (PA2 and PA3) to ON, the variable light blocking layer 280 of these pixel areas (PA2 and PA3) implements the light blocking mode. In the first pixel area PA1 where the light transmission mode is set, light passes through the variable light blocking layer 280 and enters the red color filter layer 260R, and is reflected by the red nanoparticles 100R, thereby reflecting red light. On the other hand, in the second and third pixel areas (PA2, PA3) where the light blocking mode is set, light is absorbed by the variable light blocking layer 280, and thus a red color mode is finally implemented.

Likewise, as shown in FIG. 7C, when the reflective display device 200 implements the green color mode, the switch of the variable light-shielding layer 280 in the second pixel area PA2 is set to OFF. The light transmitting mode is implemented, and the light blocking mode is implemented by setting the switch of the variable light blocking layer 280 of the first and third pixel areas (PA1 and PA3) to ON. In the second pixel area (PA2) in which light transmission is set, light passes through the variable light blocking layer 280 and green light is reflected in the green color filter layer (260G), but in the first and third pixel areas (PA1, PA3) in which light transmission mode is set, green light is reflected. ), the light is absorbed in the variable light-shielding layer 280, so a green color mode is finally implemented.

In addition, as shown in FIG. 7D, when the reflective display device 200 implements the blue color mode, the switch of the variable light-shielding layer 280 in the third pixel area PA3 is set to OFF. A light transmitting mode is implemented, and a light blocking mode is implemented by setting the switch of the variable light blocking layer 280 of the first and second pixel areas (PA1 and PA2) to ON. In the third pixel area (PA3) in which all light transmission is set, light passes through the variable light blocking layer 280 and blue light is reflected in the blue color filter layer (260B), but in the first and second pixel areas (PA1, PA2) in which light transmission mode is set, the blue light is reflected. ), the light is absorbed in the variable light-shielding layer 280, so a blue color mode is finally implemented.

Meanwhile, as shown in FIG. 7E, when the reflective display device 200 implements the white mode, the switch of the variable light-shielding layer 280 in the first to third pixel areas (PA1, PA2, and PA3) is turned off ( OFF) to implement light transmission mode. All light incident on the first to third pixel areas (PA1, PA2, PA3) corresponding to the red, green, and blue color filter layers (260R, 260G, 260B) is transmitted to the first to third pixel areas (PA1, PA1, PA3) in which the light transmission mode is set. It passes through the variable light blocking layer 280 in PA2, PA3) and is incident and reflected on the red, green, and blue color filter layers 260R, 260G, and 260B. When three types of light are reflected from the red, green, and blue color filter layers (260R, 260G, and 260B), white mode is implemented by the three primary colors of light.

In this way, according to the present invention, nanoparticles (100R, 100G, 100B) containing relatively large core particles, relatively small shell particles with a large surface area, and colorants of various colors are added to the color filter layer (260R, 260G, 260B). ), a reflective display device 200 with excellent reflection characteristics and improved color gamut can be manufactured. In addition, since the reflective display device 200 does not require a separate thin film transistor or display panel, it does not require an independent external power source and is structurally simple, making it possible to manufacture a reflective display device with excellent process reliability and process reproducibility. there is.

[Second Embodiment]

Although FIG. 5 illustrates the reflective display device 200 consisting of only three color filter layers 260R, 260G, and 260B, the reflective display device may have an independent color filter layer capable of implementing a white mode. Figure 8 is a cross-sectional view schematically showing a reflective display device divided into four pixel areas according to a second exemplary embodiment of the present invention.

As shown in FIG. 8, the reflective display device 300 according to the second embodiment of the present invention includes a first substrate 310, a second substrate 320 facing the first substrate 310, and a first substrate 320. A first electrode 330 located on the substrate 310, a second electrode 340 located on the second substrate 320, and an electrolyte located between the first electrode 310 and the second electrode 340. Layer 370, a variable light-shielding layer 380 containing electrochromic particles 382 located between the second electrode 340 and the electrolyte layer 370, between the first electrode 310 and the electrolyte layer 370. and, optionally, a counter electrode 350 located between the first electrode 330 and the color filter layer 360.

The first substrate 310 and the second substrate 320, which constitute the lower and upper substrates of the reflective display device 300, may be glass substrates, thin flexible substrates, or polymer plastic substrates.

The first electrode 330 is located inside the first substrate 310. The display device 300 according to the present invention can be used as a reflective display device that uses external light such as natural light or indoor light as a light source, and the light incident through the front surface of the second substrate 320 is transmitted through the first electrode 330. ) can be diffused, scattered, and reflected. For example, the first electrode 310 may be made of a conductive metal with good reflectivity, a transparent conductive material, and/or a mixture of these metal materials.

At this time, a thin film transistor (Tr) for driving each pixel area (PA1, PA2, PA3, and PA4) is connected to the first electrode 330 and positioned. To form a thin film transistor (Tr), gate wires (not shown) and data wires (not shown) intersect on the first substrate 310 to define each pixel area (PA1, PA2, PA3, PA4). , the thin film transistor (Tr) is connected to the gate wiring and data wiring. The thin film transistor (Tr) includes a gate electrode 311, a semiconductor layer 314, a source electrode 315, and a drain electrode 316. A gate insulating film 312 is located between the gate electrode 311 and the semiconductor layer 314.

In addition, a protective layer 317 is formed that covers the thin film transistor (Tr) and has a drain contact hole 318 exposing the drain electrode 316, and the first electrode 330 connects the drain through the drain contact hole 318. It is connected to the electrode 316 and is formed on the protective layer 317.

Meanwhile, the second electrode 340 is located inside the second substrate 320 facing the first substrate 310. For example, the second electrode 340 may be made of a transparent conductive material.

A counter electrode 350 may be positioned between the first electrode 330 and the color filter layer 360. The counter electrode 350 is used to supply insufficient ions to the electrolyte layer 370, and is made of metal oxide, PEDOT, metallocene compounds or derivatives, diphenylamine, triphenylamine, phenothiazine polymer, and/or phenoxazine polymer. It may be made of a material selected from the group consisting of.

The electrolyte layer 370 is located between the first electrode 330 and the second electrode 340. For example, the electrolyte layer 370 may be made of a solid electrolyte. For example, the electrolyte layer 370 uses a gel-type or polymer-based electrolyte containing a dissolved lithium salt. Preferably, the medium of the electrolyte layer 370 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.

Additionally, a variable light blocking layer 380 in which a plurality of electrochromic particles 382 are disposed is located on the second electrode 340. The electrochromic particles 382 may be any particles that can be converted to transparent or black through an oxidation-reduction reaction depending on whether or not power is applied. Accordingly, the electrochromic particles 382 change their light transmission characteristics due to an electrical oxidation-reduction reaction and transmit or absorb external light to implement a light transmission mode or a light blocking mode.

In one exemplary embodiment, electrochromic particles 382 may be inorganic particles having a core 282a (see FIG. 6A)-shell 282b (see FIG. 6A) structure. In another exemplary embodiment, the electrochromic particles 382 do not have a core-shell structure and may be a material that reversibly changes color to black or transparent by an electrical signal. For example, the electrochromic particles 382 may be a material represented by Formula 3 above.

Similar to that described in FIGS. 6A and 6B, depending on whether or not power is applied to the first and second electrodes 330 and 340, the shell 282b constituting the electrochromic particle 382, see FIGS. 6A and 6B. ) can change from black to transparent or from transparent to black. If the shell (282b, see Figure 6b) constituting the electrochromic particle 382 is black, external light is blocked by the electrochromic particle 382, thereby implementing a light blocking mode, and if the shell (282b, see Figure 6a) is transparent, external light is blocked. A light transmission mode can be implemented by transmitting the electrochromic particles 382.

A color filter layer 360 is located between the first electrode 340 and the electrolyte layer 370. According to the second exemplary embodiment of the present invention, the color filter layer 360 is divided into four color filter layers (360R, 360G, 360B, and 360W), and each color filter layer (360R, 360G, 360B, and 360W) is It forms the pixel area (PA1, PA2, PA3, PA4).

Specifically, the color filter layer 360 includes a red color filter layer (360R) made of red nanoparticles (100R), a green color filter layer (360G) made of green nanoparticles (100G), and a blue color filter layer (360G) made of blue nanoparticles (100B). Nanoparticles (i.e., nanoparticles to which no colorant is adsorbed, hereinafter referred to as 'white nano') consisting of a color filter layer (360B) and a shell particle (120, see FIG. 2) clustered on the surface of the core particle (110, see FIG. 2) It consists of a white color filter layer (360W) made of ‘particles’ (100W).

At this time, a partition 302 is located at the border of these pixel areas (PA1, PA2, PA3, and PA4) between the first substrate 310 and the second substrate 320, and each color filter layer (360R, 360G, 360B) , 360W), nanoparticles (100R, 100G, 100B, 100W) can be separated. If the position of the nanoparticles (100R, 100G, 100B, 100W) is fixed by the medium, the partition wall that isolates each nanoparticle (100R, 100G, 100B, 100W) can be omitted. For example, the color filter layer 360 may be formed by patterning each nanoparticle (100R, 100G, 100B, 100W) in each pixel area (PA1, PA2, PA3, and PA4) on the counter electrode 350. .

Red nanoparticles (100R), green nanoparticles (100G), blue nanoparticles (100B), and white nanoparticles (100W) are formed on the surface of the core particle (110, Figures 2 and 3) with a plurality of shell particles (120, Figure 3). 2 and 3) are clustered. Both excellent reflection characteristics due to the size of the core particles (110, see Figures 2 and 3) and excellent color gamut due to the large surface area of the shell particles (120, see Figures 2 and 3) can be achieved. In particular, by appropriately controlling the power to the variable light-shielding layer 380 made of electrochromic particles 382, not only black mode and white mode, but also different colorants (130, see FIG. 3) are adsorbed or colorants are adsorbed. Various color modes implemented in color filter layers (360R, 360G, 360B, 360W) each made of nano-particles (100R, 100G, 100B, 100W) can be implemented, which will be described in more detail.

As shown in FIG. 9A, when it is desired to implement black mode in the reflective display device 300, the first and second electrodes ( Power is applied to 330 and 340) and finally an electrical signal is applied to the variable light blocking layer 380. Accordingly, the shell 282b (see FIG. 6) of the electrochromic particles 382 constituting the variable light blocking layer 380 is discolored to black. As a result, the variable light blocking layer 380 is converted to light blocking mode in the first to fourth pixel areas (PA1, PA2, PA3, and PA4).

At this time, when external light such as natural light or indoor light is incident into the reflective display device 300, the external light is transmitted to the variable light blocking layer 380 made of electrochromic particles 382 in which the shell 282b (see FIG. 6) is discolored to black. ) and is prevented from entering the color filter layers (360R, 360G, 360B, 360W) below. Accordingly, the reflective display device 300 can implement black mode.

Meanwhile, as shown in FIGS. 9B to 9F, when the reflective display device 300 wishes to implement a color mode or a white mode, power is supplied only to the variable light blocking layer 380 in the pixel area displaying a specific color. By not applying, a light transmission mode in which only the corresponding variable light blocking layer 380 is OFF is implemented, and power is applied to the variable light blocking layer 380 in the remaining pixel area, so that only the remaining variable light blocking layer 380 is turned on. The light-shielding mode in the (ON) state can be implemented, or the light-transmitting mode can be implemented in the variable light-shielding layer 380 in all pixel areas.

For example, as shown in FIG. 9B, when the reflective display device 300 implements a red color mode, the variable light-shielding layer 380 in the first pixel area PA1 corresponding to the red color filter layer 360R ) is set to OFF, so that the variable light blocking layer 380 of the first pixel area PA1 implements a light transmission mode. By setting the switch of the variable light blocking layer 280 of the remaining pixel areas (PA2, PA3, and PA4) to ON, the variable light blocking layer 380 of these pixel areas (PA2, PA3, and PA4) implements a light blocking mode. do. In the first pixel area PA1 where the light transmission mode is set, light passes through the variable light blocking layer 380 and enters the red color filter layer 260R, and is reflected by the red nanoparticles 100R, thereby reflecting red light. On the other hand, in the second to fourth pixel areas (PA2, PA3, PA4) where the light blocking mode is set, light is absorbed by the variable light blocking layer 380, and thus a red color mode is finally implemented.

Likewise, as shown in FIG. 9C, when the reflective display device 200 implements the green color mode, the switch of the variable light-shielding layer 380 in the second pixel area PA2 is set to OFF. The light transmitting mode is implemented, and the light blocking mode is implemented by setting the switch of the variable light blocking layer 380 of the first, third, and fourth pixel areas (PA1, PA3, and PA4) to ON. In the second pixel area (PA2) where light transmission is set, light passes through the variable light blocking layer 380 and green light is reflected from the green color filter layer (360G), but in the first, third and fourth pixel areas (PA1) where light transmission mode is set. , PA3, PA4), the light is absorbed by the variable light-shielding layer 380, and a green color mode is finally implemented.

In addition, as shown in FIG. 9D, when the reflective display device 300 implements a blue color mode, the switch of the variable light-shielding layer 380 in the third pixel area PA3 is set to OFF. A light transmitting mode is implemented, and a light blocking mode is implemented by setting the switch of the variable light blocking layer 380 of the first, second, and fourth pixel areas (PA1, PA2, and PA4) to ON. In the third pixel area (PA3) where light transmission is set, light passes through the variable light blocking layer 280 and blue light is reflected from the blue color filter layer (360B), but in the first, second and fourth pixel areas (PA1) where light transmission mode is set. , PA2, PA4), the light is absorbed in the variable light-shielding layer 380, and thus a blue color mode is finally implemented.

White mode can be implemented in the following way. In one exemplary embodiment, as shown in FIG. 9E, the light transmission mode is implemented by setting the switch of the variable light-shielding layer 380 of the fourth pixel area PA4 to OFF, and the first to third pixel areas PA4 are set to OFF. The light blocking mode is implemented by setting the switch of the variable light blocking layer 380 in the pixel area (PA1, PA2, PA3) to ON. In the fourth pixel area (PA4) in which all light transmission is set, light passes through the variable light blocking layer 380 and white light is reflected in the white color filter layer (360W), but in the first to third pixel areas (PA1, PA2) in which light transmission mode is set, the white light is reflected. , PA3), the light is absorbed by the variable light-shielding layer 380, and thus white mode is finally implemented.

In another exemplary embodiment, as shown in FIG. 9F, all switches of the variable light-shielding layer 380 in the first to fourth pixel areas (PA1, PA2, PA3, and PA4) are set to OFF to enter the light transmission mode. Implement. The light incident on the first to fourth pixel areas (PA1, PA2, PA3, PA4) corresponding to the red, green, blue, and white color filter layers (360R, 360G, 360B, 360W) is all in the first to fourth pixel areas (PA1, PA2, PA3, PA4) in which the light transmission mode is set. 4 It passes through the variable light blocking layer 380 in the pixel area (PA1, PA2, PA3, PA4) and is incident and reflected on the red, green, blue, and white color filter layers (360R, 360G, 360B, 360W). When reflected from the red, green, blue, and white color filter layers (360R, 360G, 360B, 360W), white mode is implemented by the three primary colors of light.

As such, in the present invention, nanoparticles (100R, 100G, 100B, 100W) containing relatively large core particles, relatively small shell particles with a large surface area, and colorants of various colors are added to the color filter layer (360R, 360G, 360B). , 360W), a reflective display device 300 with excellent reflection characteristics and improved color gamut can be manufactured. In addition, since the reflective display device 300 does not require an independent thin film transistor or panel, it does not require an independent external power source and is structurally simple, making it possible to obtain a reflective display device with excellent process reliability and process reproducibility.

[Third Embodiment]

According to the third embodiment of the present invention, the position of the color filter layer is changed compared to the reflective display device 300 according to the second embodiment. Figure 10 is a cross-sectional view schematically showing a reflective display device divided into four pixel areas according to a third exemplary embodiment of the present invention.

As shown in FIG. 10, the reflective display device 400 according to the third embodiment of the present invention includes a first substrate 410, a second substrate 420 facing the first substrate 410, and a first substrate 420. A first electrode 430 located on the substrate 410, a second electrode 440 located on the second substrate 420, and an electrolyte located between the first electrode 430 and the second electrode 440. Layer 470 , variable light blocking layer 480 containing electrochromic particles 482 positioned between second electrode 440 and electrolyte layer 470 , first substrate 410 and first electrode 430 It includes a color filter layer 460 positioned between the first electrode 430 and the electrolyte layer 470, and optionally includes a counter electrode 450 positioned between the first electrode 430 and the electrolyte layer 470.

The first substrate 410 and the second substrate 420, which constitute the lower and upper substrates of the reflective display device 400, may be glass substrates, thin flexible substrates, or polymer plastic substrates.

The first electrode 430 is located inside the first substrate 410. The display device 400 according to the present invention can be used as a reflective display device that uses external light such as natural light or indoor light as a light source, and the light incident through the front surface of the second substrate 420 is transmitted through the first electrode 430. ) may be diffused, scattered, and reflected in the nanoparticles (100R, 100G, 100B, 100W) constituting the color filter layer 460 located below.

In an exemplary embodiment, the first electrode 430 is made of a transparent conductive material, such as indium-tin-oxide (ITO), indium-zinc-oxide (IZO). , zinc-oxide (ZnO), and indium-oxide (In ₂ O ₃ ). In another alternative embodiment, the first electrode 430 may have a multi-layer structure including a transparent conductive material and a conductive material with good reflective properties. For example, the first electrode 430 may have a triple-layer structure of an indium-tin-oxide (ITO) layer, an aluminum-palladium-copper (APC) alloy layer, and an ITO layer.

At this time, a thin film transistor (Tr) for driving each pixel area (PA1, PA2, PA3, and PA4) is connected to the first electrode 430 and is located. To form a thin film transistor (Tr), a gate wire (not shown) and a data wire (not shown) intersect on the first substrate 410 to define each pixel area (PA1, PA2, PA3, PA4). , the thin film transistor (Tr) is connected to the gate wiring and data wiring. The thin film transistor (Tr) includes a gate electrode 411, a semiconductor layer 414, a source electrode 415, and a drain electrode 416. A gate insulating film 412 is located between the gate electrode 411 and the semiconductor layer 414.

In addition, a protective layer 417 is formed that covers the thin film transistor (Tr) and has a drain contact hole 418 exposing the drain electrode 416, and the first electrode 430 connects the drain through the drain contact hole 418. It is connected to the electrode 416 and is formed on the protective layer 417.

Meanwhile, the color filter layer 460 is located on the protective layer 417 other than the area where the drain contact hole 418 is located. That is, the color filter layer 460 is located between the protective layer 417 and the first electrode 430. Similar to the color filter layer 360 of the second embodiment (see FIG. 8), the color filter layer 460 of the third embodiment of the present invention is divided into four color filter layers 460R, 460G, 460B, and 460W, Each color filter layer (460R, 460G, 460B, 460W) forms each pixel area (PA1, PA2, PA3, PA4).

Meanwhile, the second electrode 440 is located inside the second substrate 420 facing the first substrate 410. For example, the second electrode 440 may be made of a transparent conductive material.

A counter electrode 450 may be positioned between the first electrode 430 and the electrolyte layer 470. The counter electrode 450 is used to supply insufficient ions to the electrolyte layer 470, and is made of metal oxide, PEDOT, metallocene compounds or derivatives, diphenylamine, triphenylamine, phenothiazine polymer, and/or phenoxazine polymer. It may be made of a material selected from the group consisting of.

The electrolyte layer 470 is located between the first electrode 430 and the second electrode 440. For example, the electrolyte layer 470 may be made of a solid electrolyte. For example, the electrolyte layer 470 is a gel-type or polymer-based electrolyte containing a dissolved lithium salt. Preferably, the medium of the electrolyte layer 470 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.

Additionally, a variable light blocking layer 480 in which a plurality of electrochromic particles 482 are disposed is located on the second electrode 440. The electrochromic particles 482 may be any particles that can be converted to transparent or black through an oxidation-reduction reaction depending on whether or not power is applied. That is, the electrochromic particles 482 change their light transmission characteristics due to an electrical oxidation-reduction reaction and transmit or absorb external light to implement a light-blocking mode or a light-transmitting mode.

In one exemplary embodiment, electrochromic particles 482 may be inorganic particles having a core 282a (see FIG. 6A)-shell 284 (see FIG. 6A) structure. In another exemplary embodiment, the electrochromic particles 482 do not have a core-shell structure and may be a material that reversibly changes color to black or transparent by an electrical signal. For example, the electrochromic particles 482 may be a material represented by Formula 3 above.

Depending on whether power is applied to the first and second electrodes 430 and 440, the shell 282b (see FIGS. 6A and 6B) constituting the electrochromic particles 482 may change from black to transparent or from transparent to black. . If the shell (282b, see FIG. 6B) constituting the electrochromic particle 482 is black, external light is shielded by the electrochromic particle 482, thereby implementing a light-shielding mode, and if the shell (282b, see FIG. 6A) is transparent, the external light is electrically transmitted. A light transmission mode can be implemented by transmitting the discolored particles 482.

According to the third embodiment of the present invention, the color filter layer 460 located between the first substrate 410 and the first electrode 430 includes a red color filter layer 460R made of red nanoparticles 100R, and a green nano particle 460R. It consists of a green color filter layer (460G) made of particles (100G), a blue color filter layer (460B) made of blue nanoparticles (100B), and a white color filter layer (460W) made of white nanoparticles (100W).

At this time, a partition 402 is located at the border of these pixel areas (PA1, PA2, PA3, and PA4) between the first substrate 410 and the second substrate 420, and each color filter layer 460R, 460G, and 460B , 460W), nanoparticles (100R, 100G, 100B, 100W) can be separated. If the position of the nanoparticles (100R, 100G, 100B, 100W) is fixed by the medium, the partition wall that isolates each nanoparticle (100R, 100G, 100B, 100W) can be omitted. For example, the color filter layer 460 is formed by patterning each nanoparticle (100R, 100G, 100B, 100W) on the protective layer 417 formed in each pixel area (PA1, PA2, PA3, and PA4). You can.

Red nanoparticles (100R), green nanoparticles (100G), blue nanoparticles (100B), and white nanoparticles (100W) are formed on the surface of the core particle (110, Figures 2 and 3) with a plurality of shell particles (120, Figure 3). 2 and 3) are clustered. Both excellent reflection characteristics due to the size of the core particles (110, see Figures 2 and 3) and excellent color gamut due to the large surface area of the shell particles (120, see Figures 2 and 3) can be achieved.

In particular, by appropriately controlling the power to the variable light-shielding layer 480 made of electrochromic particles 482, not only black mode, but also nano mode with different colorants (130, see FIG. 3) adsorbed or without colorants adsorbed is achieved. Various color modes implemented in color filter layers (460R, 460G, 460B, 460W) made of particles (100R, 100G, 100B, and 100W) can be implemented. The black mode, white mode, and color mode implemented in the reflective display device 400 according to the third embodiment of the present invention are the same as those of the reflective display device 300 of the second embodiment (see FIGS. 9A to 9F) ), detailed description is omitted.

As such, in the present invention, nanoparticles (100R, 100G, 100B, 100W) containing relatively large core particles, relatively small shell particles with a large surface area, and colorants of various colors are added to the color filter layer (460R, 460G, 460B). , 460W), a reflective display device 400 with excellent reflection characteristics and improved color gamut can be manufactured. In addition, since the reflective display device 400 does not require an independent thin film transistor or panel, it does not require an independent external power source and is structurally simple, making it possible to obtain a reflective display device with excellent process reliability and process reproducibility.

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.

Experiment example 1: Prediction of core particle size

Reflection characteristics for each wavelength of light were predicted according to the size of the core particle. Since the luminance of a color filter is generally determined by a green colorant, it is desirable to use particles with a high green reflectance. It was predicted that the size of the core particle having reflective properties would be 100 to 500 nm to show good reflectivity, and in particular, core particles with a size of 200 to 300 nm were predicted to be preferable.

Example 1: Nanoparticle preparation (core particle: shell particle = 1:9 weight ratio; core 10 weight% )

1 g of rutile crystalline TiO ₂ (DuPont Co.) nanoparticles with a size of 250 nm were added to 100 mL ethanol solvent and dispersed using ultrasound. After stirring for 1 hour, 0.5 g of maleic acid, which acts as an organic linker, was added and stirred vigorously for 1 hour. Separately from the 250 nm TiO ₂ -ethanol dispersion, 9 g of anatase TiO ₂ (Degussa Co.) nanoparticles with a size of 15 nm were added to 100 mL of ethanol solvent and dispersed using ultrasound. While the 250 nm TiO ₂ -ethanol dispersion was strongly stirred, the prepared 15 nm TiO ₂ -ethanol dispersion was slowly added and mixed. After stirring at room temperature for more than 2 hours, precipitation and recovery were performed using a centrifuge at less than 1000 rpm. The obtained powder was heat-treated at 500°C for 1 to 2 hours using a high-temperature electric furnace to remove organic substances on the surface and prepare nanoparticles bonded in a core-shell cluster structure.

Example 2 to 5: Nanoparticle preparation

Nanoparticles were prepared by repeating the procedure of Example 1, except that the weight ratio of 250 nm TiO ₂ with a rutile crystal phase used as core particles and 15 nm TiO ₂ with an anatase crystal phase used as shell particles was changed. The weight ratio of core particles and shell particles was 1:2 (core 33% by weight; Example 2), 1:1 (core 50% by weight; Example 3), and 2:1 (core 67% by weight; Example 4), respectively. ), 5:1 (core 83% by weight; Example 5).

Example 6: Nanoparticle preparation ( TiO ₂ :SiO ₂ = 2:1)

The procedure of Example 1 except that silica (SiO ₂ ) was used instead of TiO ₂ having an anatase crystal phase as the shell particles constituting the core-shell cluster, and the core particles and shell particles were mixed at a weight ratio of 2:1. This was repeated to prepare nanoparticles.

Comparative example 1: Manufacturing nanoparticles consisting only of shell particles

Nanoparticles consisting only of shell particles with an average particle size of 15 nm were prepared. 0.5 g of maleic acid (Sigma-Aldrich Co.), which acts as an organic linker, was added to 100 mL of ethanol solvent and stirred vigorously for 1 hour. Separately from the above solution, 10 g of anatase TiO ₂ (Degussa Co.) nanoparticles with a size of 15 nm were added to 100 mL of ethanol solvent and dispersed using ultrasound. After mixing the two solutions, they were stirred at room temperature for more than 2 hours. The powder obtained by precipitation and recovery at less than 1000 rpm using a centrifuge was heat-treated at 500°C for 1 to 2 hours using a high-temperature electric furnace to remove organic matter on the surface to prepare nanoparticles consisting of only shell particles.

Comparative example 2: Manufacturing nanoparticles consisting of only core particles

Nanoparticles consisting only of core particles with an average particle size of 250 nm were prepared. The procedure of Comparative Example 1 was repeated except that TiO ₂ having a rutile crystal phase of 250 nm was used as the nanoparticles used.

Example 7: Manufacturing of reflective display elements

A reflective display device was manufactured by applying the nanoparticles prepared in Examples 1 to 6 and Comparative Examples 1 to 2 as a color filter layer. First, in order to apply the nanoparticles synthesized in Examples and Comparative Examples as a color filter, red organic dye (C.I. Mordaunt Red 11), green organic dye (C.I. Acid Green 16), and blue organic dye (C.I. Moderne) were added to the surface of the cluster. Blue 1) was used, and 0.2 g of organic dye was mixed per 10 g of nanoparticles prepared in Examples and Comparative Examples, respectively, so that these organic dyes could be sufficiently adsorbed on the surface of the shell particles.

Specifically, 10 g of cluster particles or single crystal nanoparticles prepared in Examples and Comparative Examples were dispersed and stirred in 50 mL of methanol solvent using an ultrasonic disperser and stirrer. 0.2 g of an organic dye with red, green, and blue colors and a functional group capable of bonding to metal oxides in the molecule was added to the dispersion. After stirring for 2 hours, it is precipitated and recovered using a centrifuge at less than 1000 rpm. After drying at 100°C for 10 hours, it was dispersed in PGMEA (propylene glycol monomethyl ether acetate) solvent using a binder and a dispersant, and then spin-coated on a glass substrate to complete a reflective color filter.

A nanoparticle dispersion containing electrochromic particles with a core-shell structure was prepared as follows. 30 g of indium-tin-oxide (ITO) with a primary particle size of 15 nm, 50 g of ethanol, and 120 g of 0.5 mm zirconia beads were added to a 50 mL wide-mouth bottle, and then dispersed for 5 hours using a paint shaker. After removing the beads, an ITO dispersion was prepared. Next, 15.6 g (100 mmol) of 4,4-biprydine, 21.9 g (100 mmol) of bromoethylphosphonate, and 100 g of acetonitrile were added to a three-necked flask in a nitrogen atmosphere and refluxed at a temperature of 60°C for 48 hours. After this, 8.5 g (50 mmol) of bromobenzene, 4.1 g (30 mmol) of 4-chlorobenzonitrile, and 3.4 g (20 mmol) of chlorosalicylic acid were added, and 100 g of acetonitrile was added, and the mixture was incubated at 45°C. After refluxing at high temperature for 24 hours, it was washed with ethyl ether and recrystallized from a 2:1 mixture of ethanol/ethyl ether to obtain a white substance. 2.0 g of white material was dissolved in 100 g of ethyl alcohol, mixed with 100 g of ITO dispersion with a solid content of 30% by weight, stirred, and refluxed and reacted at a temperature of 60°C for 12 hours while ultrasonic dispersion was performed. The reaction product was purified to prepare electrochromic particles with a core-shell structure. The electrochromic nanoparticle dispersion with a core-shell structure was coated on a film laminated with ITO on a PET substrate to a final thickness of 2 ㎛, then dried at a temperature of 80°C for 30 minutes to form an upper film with a variable light-shielding layer. Completed.

The solid electrolyte layer was prepared as follows. 300 g of acetonitrile, 10.0 g of polyethylene oxide (molecular weight 600K), and 10.0 g of urethane acrylate with 0.8 mol of ethylene oxide were added to a flask equipped with a stirrer, stirred for 30 minutes, and then added with 1.77 g of LiTFSi and S104 ( A transparent polymer solid electrolyte layer was prepared by adding 0.5 g of (Air product) and stirring at a temperature of 50° C. for 6 hours. In this way, the prepared solid electrolyte was coated on electrodes separated at a parallel interval of 1 mm, the solvent was dried, and the impedance was measured by irradiating UV of 0.1 J/cm2, and the ionic conductivity was 1.6 10 ^-4 S/cm. Confirmed.

The lower film was manufactured in a similar manner to the upper film with a variable light blocking layer. On a film in which ITO was laminated on a PET substrate, the nanoparticles for the color filter and the solid electrolyte layer prepared above were laminated. After drying and curing the solid electrolyte, it was coated to a thickness of 10 ㎛, dried at 80°C for 5 minutes, and then irradiated with UV light of 0.1 J/cm2 to cure the electrolyte layer. The lower film coated in this way was bonded to the upper film on which the variable light blocking layer was formed at a temperature of 50°C and then laminated to manufacture a reflective display device.

Experiment example 2: Reflection characteristics of the display element and Color gamut evaluation

Through Example 7, the reflectance, etc. of a display device to which the nanoparticles prepared in Examples 1 to 6 and Comparative Examples 1 to 2 were applied to the color filter layer were measured. First, the reflectance and surface area were measured for white nanoparticles in which organic dye was not adsorbed to the shell particles. The measurement results are shown in Figure 11. As shown in Figure 11, as the content of core particles having a size of 250 nm increased, the reflectance increased, but in inverse proportion to this, as the content of core particles increased, the surface area decreased. In particular, when using cluster bonded nanoparticles in which relatively large core particles and relatively small shell particles are blended in a ratio of 1:1 (50% by weight of core) to 5:1 (83% by weight of core), good It was confirmed that reflectance could be obtained.

In addition, according to Example 7, Quad simulation analysis was performed on a reflective display device in which nanoparticles adsorbed with red, green, and blue organic pigments were applied to the color filter layer to evaluate the reflectance and color gamut. The evaluation results are shown in Figure 12 and Table 1 below.

Reflectance and color gamut of display elements through quad simulation analysis Example Core-shell ratio Quad reflection (%) Color gamut (%) 4 2:1 34 4.70 5 5:1 35 4.50 6 2:1(SiO ₂ ) 40 5.00 Comparative Example 1 0:1 27 3.00 Comparative Example 2 1:0 35 4.00

When nanoparticles in which core particles and shell particles were mixed at a ratio of 2:1 and 5:1 were used (Examples 4 to 5), both color reproduction and reflectance were improved compared to when only shell particles were used (Comparative Example 1). . Compared to the case where only core particles were used (Comparative Example 2), the reflectance was almost similar, and the color gamut was improved. That is, when nanoparticles consisting of only small-sized shell particles are applied (Comparative Example 1), the reflectance and color gamut decrease significantly despite the improved surface area, but when the core particles and shell particles are clustered together according to the present invention. Both reflectance and color gamut can be improved compared to the case of using only shell particles. In addition, when silica with a low refractive index was used as the shell particle (Example 6), it was found that the reflectance and color reproduction rate were greatly improved compared to the comparative example using only core particles or shell particles. Therefore, according to the present invention, when using nanoparticles in which core particles and shell particles are clustered together, and preferably using shell particles having a refractive index that is significantly different from the refractive index of the core particles as nanoparticles of the color filter layer, the reflectance and /It was confirmed that the color gamut could be improved.

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-described embodiments and examples. Rather, anyone skilled in the art to which the present invention pertains can easily make various modifications and changes based on the above-described embodiments and examples. However, the fact that all such modifications and changes fall within the scope of the present invention is more clear from the attached claims.

100, 100A, 100R, 100G, 100B, 100W: Nanoparticles
110: core particle 120: shell particle
130: Colorant
200, 300, 400: Reflective display device
210, 310, 410: first substrate 220, 320, 420: second substrate
230, 330, 430: first electrode 240, 340, 440: second electrode
260, 360, 460: Color filter layer 270, 370, 470: Electrolyte layer
280, 380, 480: Variable light blocking layer 282, 382, 482: Electrochromic particles
250, 350, 450: Counter electrode
PA1, PA2, PA3, PA4: Pixel area

Claims (19)

a first substrate and a second substrate facing the first substrate;
a first electrode disposed inside the first substrate;
a second electrode disposed inside the second substrate;
An electrolyte layer located between the first electrode and the second electrode;
a variable light blocking layer including electrochromic particles positioned between the second electrode and the electrolyte layer; and
It includes a color filter layer located between the first electrode and the electrolyte layer or between the first substrate and the first electrode,
The color filter layer is composed of nanoparticles including core particles having a first size and shell particles having a second size smaller than the first size and surrounding the core particles in the form of a cluster. It comes true,
The core particles and the shell particles are respectively aluminum oxide (Al ₂ O ₃ ), zirconium oxide (ZrO ₂ ), titanium dioxide (TiO ₂ ), zinc oxide (ZnO), silica (SiO ₂ ), and tin oxide (SnO ₂ ). A reflective display device made of a material selected from the group consisting of barium fluoride (BaF ₂ ), calcium fluoride (CaF ₂ ), magnesium fluoride (MgF ₂ ), and combinations thereof.
According to clause 1,
A reflective display device in which a colorant is adsorbed on the surface of the shell particles constituting the nanoparticles.
According to clause 2,
A reflective display device wherein the colorant includes a red colorant, a green colorant, or a blue colorant.
According to clause 2,
The colorant has a hydroxyl group (-OH), a carboxylic acid group (-COOH), a phosphonic acid group (-PO ₃ H), a sulfonic acid group (-SO ₃ H), a ketoaldehyde group (-CO-COH), and these in the molecule. A reflective display device that is an organic dye having a functional group selected from the group consisting of combinations.
According to clause 1,
A reflective display device wherein the core particles have an average particle size of 100 to 500 nm.
According to clause 1,
A reflective display device wherein the shell particles have an average particle size of 1 to 50 nm.
delete According to clause 1,
A reflective display device wherein the difference between the refractive index of the core particles and the shell particles is 0.5 to 2.0.
According to clause 1,
A reflective display device wherein the refractive index of the shell particles is lower than the refractive index of the core particles.
According to clause 1,
A reflective display device wherein the core particles have a refractive index of 2.0 to 3.5, and the shell particles have a refractive index of 1.3 to 2.0.
According to claim 1 or 10,
The core particles are made of a material selected from the group consisting of zirconium oxide, titanium dioxide, zinc oxide, and combinations thereof, and the shell particles are aluminum oxide, silica, tin oxide, barium fluoride, calcium fluoride, magnesium fluoride, and these. A reflective display device made of a material selected from the group consisting of a combination of.
According to claim 1 or 2,
First to third pixel areas are defined between the first substrate and the second substrate,
The color filter layer is a reflective display device that implements different colors in the first to third pixel areas.
According to clause 12,
A first color filter layer containing the nanoparticles with a red colorant adsorbed on the shell particles is located in the first pixel area,
A second color filter layer containing the nanoparticles with a green colorant adsorbed on the shell particles is located in the second pixel area,
A reflective display device in which a third color filter layer including the nanoparticles in which a blue colorant is adsorbed to the shell particles is located in the third pixel area.
According to clause 12,
A fourth pixel area is further defined between the first substrate and the second substrate,
A reflective display device in which a fourth color filter layer containing the nanoparticles in which the colorant is not adsorbed to the shell particles is located in the fourth pixel area.
According to claim 1 or 2,
A reflective display device in which the core particles and the shell particles constituting the nanoparticles are mixed at a weight ratio of 1:1 to 5:1.
According to claim 1 or 2,
A reflective display device further comprising a counter electrode positioned between the first electrode and the electrolyte layer. According to claim 1 or 2,
A reflective display device in which the electrochromic particles are inorganic particles having a core-shell structure.
According to clause 17,
The core constituting the electrochromic particle is selected from the group consisting of indium-tin-oxide, indium-zinc-oxide, antimony-tin-oxide, fluorine-doped tin-oxide, aluminum-zinc oxide, and combinations thereof. A reflective display device made of conductive material.
According to clause 17,
A reflective display device wherein the core constituting the electrochromic particles is made of a non-conductive metal oxide selected from the group consisting of titanium oxide, zinc oxide, silica, and combinations thereof.

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