CN101118361A - Electrophoretic display device and its structure - Google Patents

Abstract

An electrophoretic display device having an improved front reflectance, the device comprising: a first substrate including a first electrode of a transparent material of a first optical pattern; a second substrate facing the first substrate and including a plurality of a second electrode; a spacer inserted between the first substrate and the second substrate to define a space between the first substrate and the second substrate; and an image display layer formed through the first substrate and the second substrate and In the space formed by the spacer, an image is displayed by an electric field generated between the first electrode and the second electrode.

Description

Electrophoretic display device and its structure

This application claims the priority of Korean Patent Application No. 2006-72281 filed with the Korean Intellectual Property Office on July 31, 2006 and Korean Patent Application No. 2007-21261 filed with the Korean Intellectual Property Office on March 5, 2007, respectively, This application is hereby disclosed in its entirety by reference.

technical field

The present invention relates to an electrophoretic display device, and more particularly, to an electrophoretic display device with improved front reflectance.

Background technique

Electrophoretic display devices display visible images by arranging charged pigment particles dispersed in a liquid medium with an applied electric field.

FIG. 1 is a cross-sectional view showing a conventional electrophoretic display device. As shown in FIG. 1 , an electrophoretic display device 1 is realized by two facing substrates 10 and 20 on which electrodes 12 and 22 are respectively formed. An image display layer 40 is formed between the two substrates 10 and 20 . The image display layer 40 includes an insulating material 42 , and electrophoretic particles 44 and 46 with different charges dispersed in the insulating material 42 . An electric field applied between the electrodes 12 and 14 moves the oppositely polarized electrophoretic particles 44 and 46 in different directions, thereby displaying successive images. A background color contrasting with the color of the electrophoretic particles is carried by the insulating material.

Since the electrophoretic display device is totally reflective, the electrophoretic display device consumes less energy than a liquid crystal display device, a plasma display panel, and an organic light emitting device. In addition, since the electrophoretic display device provides paper-like display quality, eye fatigue is reduced.

In FIG. 1, a conventional electrophoretic display device 1 is implemented in such a manner that charged particles are arranged on the inner surface of an electrode 12 formed on a substrate 10 to reflect external incident light. Since the inner surface of the electrode 12 facing the charged particles is flat, incident light arriving at an incident angle θ ₁ is reflected at a reflection angle θ ₂ , which is equal to the incident angle _{θ 1 .} Therefore, the conventional electrophoretic display device 1 cannot completely reflect incident light in the front direction with respect to the substrate 10 .

For this reason, conventional electrophoretic display devices cannot provide images with desired brightness.

Contents of the invention

The present invention provides an electrophoretic display device having an optical pattern capable of enhancing front reflectance, and a method for constructing such an electrophoretic display device.

In an exemplary embodiment of the present invention, an electrophoretic display device includes: a first substrate including a first electrode of a transparent material having a first optical pattern for improving reflectance; a second substrate that is the same as the first substrate. facing, and including a second electrode; a spacer inserted between the first substrate and the second substrate to define a space between the first substrate and the second substrate; and an image display layer formed through the first substrate and the second substrate. In the space formed by the second substrate and the spacer, an image can be displayed by an electric field generated between the first electrode and the second electrode.

In some embodiments, the first optical pattern may be convex or concave.

In some embodiments, the first substrate includes: a transparent substrate; a pattern layer formed on the transparent substrate and having a second pattern corresponding to the first optical pattern; wherein the first electrode is formed along the second pattern.

In some embodiments, the first electrode is provided with a separator insertion groove into which one end of the separator is tightly inserted, wherein the separator insertion groove is formed on the boundary of the first optical pattern groove.

In some embodiments, the image display layer includes: a dielectric fluid (dielectric fluid) filled in the space formed by the first substrate and the second substrate and the spacer; white charged particles dispersed in the dielectric fluid; White charged particles are dispersed in the dielectric liquid, wherein the white charged particles and the non-white charged particles have different polarities.

In some embodiments, the dielectric liquid may be a gas or a liquid.

In some embodiments, the image display layer may be an e-fluid powder.

In some embodiments, the image display layer includes: a plurality of containers arranged in spaces between the first and second substrates and the separator; a dielectric liquid filled in the containers; white charged particles dispersed in in the dielectric liquid; and non-white charged particles dispersed in the dielectric liquid, wherein the white charged particles and the non-white charged particles have different polarities.

In some embodiments, the container has a curved upper wall such that it mates closely with the first optical pattern of the first electrode.

In some embodiments, the image display layer includes: a plurality of containers arranged in spaces between the first and second substrates and the separator; and electronic fluid powder filled in the containers.

In some embodiments, the first optical pattern may be formed with at least one of a concave shape or a convex shape on a unit pixel basis.

In some embodiments, the concave shape may be at least one of a concave lens shape, a concave conical shape, or a concave polygonal pyramid shape.

In some embodiments, the convex shape may be at least one of a convex lens shape, a convex cone shape, or a convex polygonal cone shape.

In some embodiments, the first electrode may be provided with a spacer insertion groove into which one end of the spacer is tightly inserted, wherein the spacer insertion groove is formed on the boundary of the first optical pattern. groove.

In some embodiments, the image display layer may include: a dielectric liquid filled in a space formed by the first and second substrates and the spacer; white charged particles dispersed in the dielectric liquid; and non-white charged particles , dispersed in a dielectric liquid, wherein the white charged particles and the non-white charged particles have different polarities.

In some embodiments, the image display layer may include: a plurality of containers arranged in spaces between the first and second substrates and the separator; a dielectric liquid filled in the containers; white charged particles dispersed in the dielectric liquid; and non-white charged particles dispersed in the dielectric liquid, wherein the white charged particles and the non-white charged particles have different polarities.

In an exemplary embodiment of the present invention, an electrophoretic display device includes: a first substrate including a first electrode of a transparent material having a first optical pattern for improving front reflectance; a second substrate and the first substrate facing each other and including a second electrode; and an image display layer formed in a space formed by the first substrate and the second substrate to display an image according to an electric field applied between the first electrode and the second electrode, wherein , the image display layer may include: a plurality of containers arranged in a space between the first substrate and the second substrate; a dielectric liquid filled in the containers; white charged particles dispersed in the dielectric liquid; White charged particles are dispersed in the dielectric liquid, wherein the white charged particles and the non-white charged particles have different polarities.

In some embodiments, the container is formed of a soft material such that the upper wall of the container is tightly fitted to the first optical pattern of the first electrode by pressure between the first substrate and the second substrate.

In an exemplary embodiment of the present invention, a method of constructing an electrophoretic display device includes: forming an optical pattern on one surface of a first substrate; forming a transparent material along the optical pattern on the surface of the first substrate on which the optical pattern is formed forming a second electrode of a transparent material on the surface of the second substrate; forming a spacer on the second substrate; forming an image display layer on the second substrate; and combining the first substrate and the second substrate, An image display layer is thus interposed between the first substrate and the second substrate.

In some embodiments, forming the optical pattern includes: disposing an organic layer on a surface of the first substrate; and forming the optical pattern by patterning the organic layer using a lithography process.

In some embodiments, the step of forming the optical pattern uses an embossing process or a lithographic process.

In some embodiments, the image display layer is formed by disposing electronic fluid powder in a space formed by the first and second substrates and the spacer.

In an exemplary embodiment of the present invention, a method of constructing an electrophoretic display device includes: forming an optical pattern on one surface of a first substrate; forming a transparent material along the optical pattern on the surface of the first substrate on which the optical pattern is formed forming a second electrode of a transparent material on the surface of the second substrate; forming an image display layer on the second substrate; and combining the first substrate and the second substrate, thereby forming the first substrate and the second substrate An image display layer is inserted between them, wherein the image display layer includes: a plurality of containers arranged in the space between the first substrate and the second substrate; a dielectric liquid filled in the containers; white charged particles dispersed in in the dielectric liquid; and non-white charged particles dispersed in the dielectric liquid, wherein the white charged particles and the non-white charged particles have different polarities.

In some embodiments, the container is formed of a soft material such that the upper wall of the container is tightly fitted to the first optical pattern of the first electrode by pressure between the first substrate and the second substrate.

Description of drawings

The above and other features and advantages of the present invention will become more apparent through the following detailed description in conjunction with the accompanying drawings, wherein:

1 is a cross-sectional view showing a conventional electrophoretic display device;

2 is a cross-sectional view showing an electrophoretic display device according to a first exemplary embodiment of the present invention;

3 is a cross-sectional view showing a second substrate shown in FIG. 2;

4 is a cross-sectional view illustrating a modification of the electrophoretic display device of FIG. 2;

5 is a cross-sectional view illustrating an electrophoretic display device according to a second exemplary embodiment of the present invention;

6 is a cross-sectional view showing an electrophoretic display device according to a third exemplary embodiment of the present invention;

7 is a cross-sectional view illustrating a modification of the electrophoretic display device of FIG. 6;

8A and 8B are perspective views illustrating a first substrate of an electrophoretic display device according to a fourth exemplary embodiment of the present invention;

9A to 9E are perspective views illustrating optical patterns of an electrophoretic display device according to a fourth exemplary embodiment of the present invention;

10A is a perspective view illustrating another optical pattern of an electrophoretic display device according to a fourth exemplary embodiment of the present invention;

Figure 10B is a cross-sectional view along line II-II' in Figure 10; and

11A to 11G are diagrams illustrating a process of constructing the electrophoretic display device of FIG. 2 .

FIG. 12 is a cross-sectional view illustrating a modification of the electrophoretic display device of FIG. 4 .

FIG. 13 is a cross-sectional view illustrating a modification of the electrophoretic display device of FIG. 7 .

Detailed ways

Exemplary embodiments of the present invention are described in detail with reference to the drawings. The same reference numbers are used throughout the drawings to refer to the same or similar parts. Detailed descriptions of well-known functions and structures incorporated herein will be omitted to avoid obscuring the subject matter of the present invention.

In the following detailed description, preferred embodiments are shown and described, simply by way of illustration of the best mode contemplated by the inventors of carrying out the invention. It will be understood that the invention is capable of modification in all obvious aspects thereof. Accordingly, the drawings and description are to be regarded as illustrative in nature.

FIG. 2 is a cross-sectional view showing an electrophoretic display device according to a first exemplary embodiment of the present invention.

Referring to FIG. 2 , the electrophoretic display device 100 includes: a first substrate 110 , a second substrate 120 , a spacer 130 and an image display layer 140 .

The first substrate 110 includes: a transparent substrate 114 , a pattern layer 111 , and a first electrode 112 of the transparent electrode. The first substrate 110 may be a color filter substrate including color filters (not shown).

The transparent substrate 114 and the first electrode 112 transmit incident light from the outside to reach the image display layer 140 and reflect the incident light on the image display layer 140 toward a viewer (Z-axis direction) with less loss. The pattern layer 111 is formed on the transparent substrate 114, and has a concave shape. The first electrode 112 includes an optical pattern 111 a having a convex shape and a spacer insertion groove 116 , and serves as a common electrode. The optical pattern 111 a having a convex shape corresponds to the concave pattern of the pattern layer 111 . The inclination of each optical pattern 111 a is determined according to the space between the spacers 130 . The curvature of the optical pattern 111a is designed to maximize the reflection of incident light to the front viewing direction.

A spacer insertion groove 116 into which an upper end of the spacer 130 is inserted is formed on a boundary between unit pixels in the first electrode 112 . In case of forming the spacer insertion groove 116 , the surface of the first electrode 112 may be formed at a certain height below the upper end of the spacer 130 . If the surface of the first electrode 112 is generated under the upper end of the spacer 130 , no gap is formed between the upper surface of the image display layer 140 and the first electrode 112 . In this structure, the image display layer 140 closely fits the optical pattern 111 a of the first electrode 112 so that the image display layer 140 has an upper surface whose outline is the same as the optical pattern of the first electrode 112 . The curvature of the image display layer 140 increases the front reflectance of incident light.

The term front reflectance means the amount of light reflected in a direction perpendicular to the surface of the first substrate 110 (ie, a Z-axis direction toward a viewer). If the front reflectance is high, the luminance of the display device increases even in the same ambient light environment.

The image display layer 140 is closely matched with the first electrode 112 by inserting the spacer into the groove 116, which reduces the distance between the first electrode 112 and the second electrode 122 of the transparent electrode, thereby reducing the required driving voltage and reduces power consumption.

The second substrate 120 includes: a transparent substrate 124 , a thin film transistor 128 , a protection layer 126 and a second electrode 122 . The second substrate 120 faces the first substrate 110 . The second substrate 120 may be a thin film transistor substrate on which thin film transistors 128 are arranged. Thin film transistors 128 are arranged on the transparent substrate 124, and serve as switches for independently driving the unit pixels U. A protective layer 126 is formed on the thin film transistor 128 .

The second electrode 122 is arranged on a unit pixel basis on the protective layer 126 and serves as a pixel electrode corresponding to the first electrode 112 serving as a common electrode. Unlike the first electrode 112 , the second electrode 122 formed on the transparent substrate 124 is independently arranged in each space defined by the spacer 130 .

The spacer 130 is interposed between the first substrate 110 and the second substrate 120 , thereby ensuring a certain distance between the first substrate 110 and the second substrate 120 . Each independent space formed between the first substrate 110 and the second substrate 120 by the spacer 130 corresponds to a unit pixel U. Referring to FIG.

The image display layer 140 is filled in a space formed by the first substrate 110 and the second substrate 120 and the spacer 130 . The image display layer 140 is driven by an electric field generated between the first electrode 112 and the second electrode 122, thereby representing an image.

The image display layer 140 may include: a dielectric liquid 142 , white-colored charged particles 144 and non-white charged particles 146 . The dielectric liquid 142 may be a liquid or a gas, and is transparent so as to transmit light. The dielectric liquid 142 has insulating properties making it unaffected by electric fields.

The white charged particles 144 are dispersed in the dielectric liquid 142, and the white charged particles 144 are charged with a charge of a predetermined polarity. By an electric field formed when DC voltages of different polarities are applied to the first electrode 112 and the second electrode 122, the negatively or positively charged white charged particles 144 move toward the oppositely charged electrode. For example, if the white charged particles 144 are negatively charged, and a positive voltage is applied to the first electrode 112 , the white charged particles 144 move to the first electrode 112 , thereby reflecting all incident light through the white charged particles 144 . Then, the electrophoretic display device displays white.

Non-white charged particles 146 are dispersed in dielectric liquid 142 and have an opposite electrode to white charged particles 144 . Since the non-white charged particles 146 are charged with a polarity opposite to that of the white charged particles 144, when a voltage is applied to the first electrode 112 and the second electrode 122, the non-white charged particles 146 move to the opposite polarity to that of the white charged particles. 144 in the opposite direction. The non-white charged particles 146 are typically coated with a black or blue dye. In the case of realizing a color display device, the particles can be dyed with other color pigments.

In some embodiments, the image display layer 140 may be realized by using Electronic Liquid Powder. E-fluid powder is a display material developed by the Japanese company Bridgestone, known as a fluid-like powder. Electronic fluid powder is a solid powder with fluid properties. The e-fluid powder is very sensitive to electricity and has a color such that when a voltage is applied, the e-fluid powder moves in the air to display images. Since the electronic fluid powder can move in the air by using air as a medium, it is easy to implement a display device using the electronic fluid powder. If the electronic fluid powder is used as the image display layer of the present invention, the electronic fluid powder does not form a gap that may occur between the image display layer 140 and the first electrode 112 of the first substrate 110 .

FIG. 3 is a cross-sectional view illustrating the second substrate 120 shown in FIG. 2 . 3, the thin film transistor 128 formed on the second substrate 120 includes a gate electrode 128G, a gate insulating layer 123, an active layer 128A, an ohmic contact layer 128O, a source electrode 128S, and a drain electrode 128D. The drain electrode 128D of the thin film transistor 128 is connected to the second electrode 122 through the contact hole 106 of the protective layer 126 .

The gate electrode 128G is connected to a gate line (not shown), and a driving voltage from the gate line is applied to the gate electrode 128G. The gate insulating layer 123 isolates the gate electrode 128G from the source electrode 128S and the drain electrode 128D, and isolates the gate electrode 128G from the active layer 128A. The active layer 128A overlaps the gate electrode 128G with the gate insulating layer 123 interposed therebetween to form a channel between the source electrode 128S and the drain electrode 128D.

An ohmic contact layer 128O may also be formed on the active layer 128A. The ohmic contact layer 128O reduces contact resistance between the source electrode 128S or the drain electrode 128D and the active layer 128A to improve characteristics of the thin film transistor 128 . The source electrode 128S is connected to one end of the active layer 128A through the ohmic contact layer 128O, and is also connected to a data line (not shown) to supply a grayscale display voltage from the data line to the source electrode 128S. The drain electrode 128D is connected to the other end of the source layer 128A while facing the source electrode 128S, and is also connected to the second electrode 122 . In this case, the grayscale display voltage refers to a voltage corresponding to the grayscale of data.

A protective layer 126 is formed on the thin film transistor 128 to protect the thin film transistor 128 . The protective layer 126 includes a contact hole 106 exposing a portion of the drain electrode 128D to connect the drain electrode 128D and the second electrode 122 . The grayscale display voltage from the drain electrode 128D is applied to the second electrode 122, and the second electrode 122 generates an electric field together with the first electrode 112 of the first substrate 110 shown in FIG. The generated electric field moves the white charged particles 144 and the non-white charged particles 146 in a predetermined direction, and an image is displayed.

FIG. 4 is a cross-sectional view illustrating a modification of the electrophoretic display device of FIG. 2 .

As shown in FIG. 4 , the image display layer 140a may include: a capsule 141a, a dielectric liquid 142a, white charged particles 144a and non-white charged particles 146a. The container 141a is received in a space defined by the partition 130 and the first substrate 110 and the second substrate 120, and the container 141a ensures movement of the white charged particles 144a and the non-white charged particles 146a.

When the dielectric liquid is directly filled between the first substrate 110 and the second substrate 120, precipitation of charged particles may occur, so it is preferable to put the particles in a container to prevent the precipitation of charged particles and improve the image display layer 140a. response speed. The upper surface of the container 141 a closely fits the optical pattern of the curved surface of the first electrode 112 . To this end, the optical convex pattern of the first electrode 112 should be formed in such a way that the convex curvature is the same as the curvature of the circumference of the container 141a.

The container 141a is filled with a dielectric liquid 142a, and white charged particles 144a and non-white charged particles 146a are dispersed in the dielectric liquid 142a. Since the structures and functions of the dielectric liquid 142a, white charged particles 144a, and non-white charged particles 146a are the same as those of the dielectric liquid 142, white charged particles 144, and non-white charged particles 146 shown in FIG. 2, their detailed descriptions are omitted.

In some embodiments, the container 141a may be realized by filling with air and e-fluid powder.

FIG. 12 is a cross-sectional view illustrating a modification of the electrophoretic display device of FIG. 4 .

The electrophoretic display device 100b includes the same components as in FIG. 4 except that the spacer 130 is removed. Therefore, descriptions of the same components will be omitted in the following description.

As shown in FIG. 12, the container 141b is formed of a spherical soft material. Therefore, when pressure is applied to the container 141 b through the first substrate 110 and the second substrate 120 , the upper wall of the container 141 b closely fits with the first optical pattern 111 a of the first electrode 112 . Alternatively, the containers 141b are in contact with each other.

5 is a cross-sectional view showing an electrophoretic display device according to a second exemplary embodiment of the present invention.

As shown in FIG. 5, the electrophoretic display device 200 includes: a first substrate 210, a second substrate 220 facing the first substrate 210, a spacer 230 inserted between the first substrate 210 and the second substrate 220, and an image display Layer 240.

The first substrate 210 includes: a transparent substrate 214 , a pattern layer 211 and a first electrode 212 of the transparent electrode. The first substrate 210 may be a color filter substrate including color filters (not shown).

The pattern layer 211 is formed on a transparent substrate 214 having a convex pattern. The first electrode 212 includes a concave optical pattern 211a and a spacer insertion groove 216, and the first electrode 212 serves as a common electrode. The concave optical pattern 211 a corresponds to the convex pattern of the pattern layer 211 .

The inclination of each concave optical pattern 211 a is determined according to the area between the spacers 230 . The curvature of the concave optical pattern 211a is designed to maximize the reflection of incident light to the front viewing direction (Z-axis direction).

A spacer insertion groove 216 into which an upper end of the spacer 230 is inserted is formed on a boundary between the unit pixels U in the first electrode 212 . In case of forming the spacer insertion groove 216 , the surface of the first electrode 212 may be formed at a certain height below the upper end of the spacer 230 .

The structures of the second substrate 220 including the second electrode 222 of the transparent electrode and the transparent substrate 224 , the spacer 230 and the image display layer 240 are substantially the same as the second substrate 120 , the spacer 130 and the image display layer 140 in FIG. 2 . Therefore, repeated descriptions will be omitted.

6 is a cross-sectional view showing an electrophoretic display device according to a third exemplary embodiment of the present invention.

As shown in FIG. 6 , the electrophoretic display device 300 includes: a first substrate 310 , a second substrate 320 , a spacer 330 and an image display layer 340 .

The first substrate 310 may be a color filter substrate including a transparent substrate 312, a black matrix (black matrix) 314, a color filter 316, an overcoat layer 317, and a first electrode 318 of a transparent electrode. . A black matrix 314 is formed on the transparent substrate 312 to block light between the unit pixels U. The color filter 316 realizes the color of the electrophoretic display device 300 . The cover layer 317 and the first electrode 318 have a good form of step coverage. The first electrode 318 is formed on the capping layer 317, and the first electrode 318 serves as a common electrode.

The transparent substrate 312 and the transparent electrode 318 transmit incident light from the outside to reach the image display layer 340 or reflect the incident light on the image display layer 340 with less loss. The transparent electrode 318 includes a spacer insertion groove 302 and an optical pattern having a plurality of convex lens shapes 304a. The plurality of convex lens shapes 304 a of the optical pattern corresponds to the pattern of concave lens shapes of the cover layer 317 . The size of the plurality of convex lens shapes 304a of the optical pattern may be less than 15 μm. The plurality of convex lens shapes 304a of the optical pattern may have the same size. The plurality of lenticular shapes 304a of the optical pattern can vary in size and have any size in the range of less than 15 μm. Any size of the plurality of convex lens shapes 304a of the optical pattern can be selected under the condition of maximizing the reflectance.

A spacer insertion groove 302 into which an upper end of a spacer 330 is inserted is formed on a boundary between unit pixels U in the transparent electrode 318 . In case of forming the spacer insertion groove 302 , the surface of the transparent electrode 318 may be formed at a certain height below the upper end of the spacer 330 .

The structures of the second substrate 320 , the spacer 330 and the image display layer 340 are substantially the same as those of the second substrate 120 , the spacer 130 and the image display layer 140 in FIG. 2 .

FIG. 7 is a cross-sectional view illustrating a modification of the electrophoretic display device of FIG. 6 .

As shown in FIG. 7, the image display layer 340a includes: a container 341a, a dielectric liquid 342a, white charged particles 344a and non-white charged particles 346a. The image display layer 340 has the same structure as the image display layer 140a of FIG. 4 .

FIG. 13 is a cross-sectional view illustrating a modification of the electrophoretic display device of FIG. 7 .

The electrophoretic display device 300b includes the same components as in FIG. 7 except that the spacer 330 is removed. Therefore, descriptions of the same components will be omitted in the following description.

As shown in FIG. 13, the container 341b is formed of a spherical soft material. Therefore, when pressure is applied to the container 341 b through the first substrate 310 and the second substrate 320 , the upper wall of the container 341 b closely fits the plurality of convex lens shapes 304 a of the optical pattern of the first electrode 318 . Alternatively, the containers 341b are in contact with each other.

8A and 8B are perspective views illustrating a first substrate according to a fourth exemplary embodiment of the present invention.

As shown in FIG. 8A and FIG. 8B , the first substrate 410 of the electrophoretic display device includes: a transparent substrate 412 , a black matrix 414 , a color filter 416 , a cover layer 417 and a transparent electrode 418 .

The transparent electrode 418 includes a spacer insertion groove 402 and an optical pattern having a plurality of concave lens shapes 404a. The plurality of concave lens shapes 404 a of the optical pattern corresponds to the pattern of convex lens shapes of the cover layer 417 . The size of the plurality of concave lens shapes 404a of the optical pattern may be less than 15 μm. The plurality of concave lens shapes 404a of the optical pattern may have the same size. The plurality of concave lens shapes 404a of the optical pattern can vary in size and have any size in the range of less than 15 μm. Any size of the plurality of concave lens shapes 404a of the optical pattern can be selected to maximize reflectivity.

The structures of the transparent substrate 412 , the black matrix 414 , the color filters 416 and the covering layer 417 are substantially the same as those of the transparent substrate 312 , the black matrix 314 , the color filters 316 and the covering layer 317 in FIG. 6 .

Although the first substrate of the electrophoretic display device having an optical pattern in a convex or concave lens shape has been explained, the optical pattern of the first substrate is not limited to a convex or concave lens shape. As shown in FIGS. 9A to 9E , the optical patterns formed in the first substrates 610, 710, 810, 910, and 1010 may be, for example, a conical convex shape 604a, a triangular pyramid 704a, a quadrangular pyramid 804a, a pentagonal pyramid 904a and hexagonal pyramid 1004a.

Alternatively, the transparent electrode of the first substrate may have an optical pattern in which concave lenses and convex lenses are mixed as shown in FIG. 10A.

FIG. 10B is a cross-sectional view along line II-II' in FIG. 10 .

As shown in FIGS. 10A and 10B , the first substrate 510 includes: a transparent substrate 512 , a black matrix 514 , a color filter 516 , a cover layer 517 and a transparent electrode 518 .

The transparent electrode 518 includes a spacer insertion groove 502 and a mixed optical pattern having a plurality of convex lens shapes 504a and concave lens shapes 504b. The blended optical pattern corresponds to the concave and convex lens shape pattern of the cover layer 517 .

The sizes of the plurality of convex lens shapes 504a and concave lens shapes 504b may be the same or different. The plurality of convex lens shapes 504a and concave lens shapes 504b may have any size in the range of less than 15 μm.

The structures of the transparent substrate 512 , black matrix 514 , color filter 516 and cover layer 517 are substantially the same as those of the transparent substrate 312 , black matrix 314 , color filter 316 and cover layer 317 in FIG. 6 . Although an optical pattern formed in a mixed shape of a concave lens and a convex lens shape has been explained, the optical pattern of the first substrate is not limited thereto, and may be in the form of concave or convex cones, triangular pyramids, quadrangular pyramids, pentagonal pyramids, and hexagonal pyramids. The combination of body and so on forms a mixed pattern.

11A to 11G are diagrams illustrating steps of constructing an electrophoretic display device according to an exemplary embodiment of the present invention.

As shown in FIG. 11A , a second electrode 122 is formed on a transparent substrate 124 . A plurality of thin film transistors (not shown) serving as switching means for determining timing and voltage levels to be applied are formed on the transparent substrate 124 . The thin film transistor is connected to the second electrode 122 .

In a later process, the second electrode 122 is formed on the second substrate 124 in a predetermined pattern corresponding to the spacer pattern formed on the transparent substrate 124 . That is, the second electrode 122 is formed based on the unit pixel defined by the spacer 130 .

After the second electrode 122 is formed, a spacer pattern is formed on the second substrate 124 as shown in FIG. 11B . The partition 130 is implemented in a form having a plurality of horizontal and vertical walls intersecting each other, thereby forming a plurality of unit pixels. Then, an upwardly opened cuboid shape is formed by the partition 130 and the second substrate 120 .

As shown in FIG. 11C , the image display layer 140 is formed with unit pixels defined by the spacer 130 and the second substrate 120 . The image display layer 140 may include: a dielectric liquid, white charged particles, and non-white charged particles, or the image display layer 140 may be implemented with electronic fluid powder. In some embodiments, the image display layer 140 may be a container filled with a dielectric liquid, white charged particles, and non-white charged particles. An optical pattern having a curved shape is formed on the surface of the first substrate 110 .

As shown in FIG. 11D , an organic layer 111 having a predetermined thickness is formed on a transparent substrate 114 .

After the organic layer 111 is formed, as shown in FIG. 11E , the organic layer 111 is patterned to form an optical pattern 111 a having a curved shape. The optical pattern 111a may be formed using a lithography process or an imprint process. In the case of using the imprint process, the optical pattern 111a is formed by placing a thermosetting or ultraviolet setting organic material on the transparent substrate 114 using a mold of the opposite shape to the optical pattern 111a. Heat or ultraviolet rays are applied to the transparent substrate 114 while the mold is pressed on the organic layer 111 . Thereafter, when the mold is removed, the concave patterns 111a are formed on the transparent substrate 114 . An optical pattern can be simply formed using an imprint process instead of a lithography process.

After the concave pattern 111a is formed, as shown in FIG. 11F , the first electrode 112 of a transparent material is formed on the surface of the transparent substrate 114 along the concave pattern 111a. That is, the first electrode 112 is formed along the optical pattern 111a by placing a transparent material electrode having a thinner thickness on the transparent substrate 144 on which the optical pattern is formed.

The order of the process of forming the optical pattern 111a and the first electrode 112 on the transparent substrate 124, and the process of forming the first electrode 112, the spacer 130, and the image display layer 140 on the second substrate 120 may be changed, or may be performed simultaneously.

As shown in FIG. 11G , the first base 110 is combined with the second base 120 such that the spacer insertion groove 116 of the first base 110 is tightly inserted into the upper side of the spacer 130 . The electrophoretic display device 100 is realized by combining the first substrate 110 and the second substrate 120 .

Although the exemplary embodiments of the present invention have been described in detail above, it should be clearly understood that various changes and/or modifications of the basic inventive concepts taught herein that are obvious to those skilled in the art still fall within the scope of the invention defined in the claims. spirit and scope of the invention.

As described above, the electrophoretic display device of the present invention is formed such that the transparent electrodes provided on the display substrate are formed so that each unit pixel has a curved surface so that the frontal reflection of incident light is maximized, therefore, even in the same ambient light environment Brightness characteristics can also be improved.

In addition, the electrophoretic display device of the present invention is advantageous in that the front reflectance is adjusted by modifying the optical pattern formed on the display substrate.

Claims (24)

1. An electrophoretic display device, comprising: a first substrate comprising a first electrode of a transparent material having a first optical pattern for improving front reflectance; a second substrate facing the first substrate and including a second electrode; a spacer inserted between the first base and the second base to define a space between the first base and the second base; and An image display layer is formed in a space formed by the first and second substrates and the spacer to display an image according to an electric field applied between the first and second electrodes. 2. The electrophoretic display device of claim 1, wherein the first optical pattern is convex or concave. 3. The electrophoretic display device according to claim 2, wherein the first substrate comprises: transparent base; and a pattern layer formed on the transparent substrate and having a second pattern corresponding to the first optical pattern; Wherein, the first electrodes are formed along the second pattern. 4. The electrophoretic display device according to claim 3, wherein the first electrode is provided with a spacer insertion groove into which one end of the spacer is tightly inserted, wherein, in the first optical pattern The separator insertion groove is formed on the boundary. 5. The electrophoretic display device according to claim 2, wherein the image display layer comprises: a dielectric liquid filled in a space formed by the first and second substrates and the separator; white charged particles, dispersed in a dielectric liquid; and non-white charged particles, dispersed in a dielectric liquid, Wherein, the white charged particles and the non-white charged particles have different polarities. 6. The electrophoretic display device of claim 5, wherein the dielectric liquid is a gas or a liquid. 7. The electrophoretic display device of claim 2, wherein the image display layer is electronic fluid powder. 8. The electrophoretic display device according to claim 2, wherein the image display layer comprises: a plurality of containers disposed in the space between the first and second bases and the divider; a dielectric liquid filled in said container; white charged particles, dispersed in a dielectric liquid; and non-white charged particles, dispersed in a dielectric liquid, Wherein, the white charged particles and the non-white charged particles have different polarities. 9. The electrophoretic display device of claim 8, wherein the container has a curved upper wall such that it closely fits with the first optical pattern of the first electrode. 10. The electrophoretic display device according to claim 2, wherein the image display layer comprises: a plurality of containers disposed in the space between the first and second bases and the divider; and Electronic fluid powder, filled in the container. 11. The electrophoretic display device of claim 1, wherein the first optical pattern is formed with at least one of a concave shape or a convex shape on a unit pixel basis. 12. The electrophoretic display device of claim 11, wherein the concave shape is at least one of a concave lens shape, a concave conical shape, or a concave polygonal pyramid shape. 13. The electrophoretic display device of claim 11, wherein the convex shape is at least one of a convex lens shape, a convex conical shape, or a convex polygonal pyramid shape. 14. The electrophoretic display device according to claim 11, wherein the first electrode is provided with a spacer insertion groove, and one end of the spacer is inserted into the spacer insertion groove tightly, wherein, in the first optical pattern The separator insertion groove is formed on the boundary. 15. The electrophoretic display device according to claim 14, wherein the image display layer comprises: a dielectric liquid filled in a space formed by the first and second substrates and the separator; white charged particles, dispersed in a dielectric liquid; and non-white charged particles, dispersed in a dielectric liquid, Wherein, the white charged particles and the non-white charged particles have different polarities. 16. The electrophoretic display device according to claim 14, wherein the image display layer comprises: a plurality of containers disposed in the space between the first and second bases and the divider; a dielectric liquid filled in said container; white charged particles, dispersed in a dielectric liquid; and non-white charged particles, dispersed in a dielectric liquid, Wherein, the white charged particles and the non-white charged particles have different polarities. 17. A method of constructing an electrophoretic display device, the method comprising: forming an optical pattern on a surface of the first substrate; forming a first electrode of transparent material along the optical pattern on the surface of the first substrate on which the optical pattern is formed; forming a second electrode of transparent material on the surface of the second substrate; forming spacers on the second substrate; forming an image display layer on the second substrate; and The first substrate and the second substrate are combined such that an image display layer is interposed between the first substrate and the second substrate. 18. The method of claim 17, wherein forming the optical pattern comprises: placing an organic layer on the surface of the first substrate; and The optical pattern is formed by patterning the organic layer. 19. The method of claim 17, wherein the step of forming the optical pattern uses an imprint process or a lithography process. 20. The method of claim 17, wherein the image display layer is formed by disposing electronic fluid powder in a space formed by the first and second substrates and the spacer. 21. An electrophoretic display device comprising: a first substrate comprising a first electrode of a transparent material having a first optical pattern for improving front reflectance; a second substrate facing the first substrate and including a second electrode; and an image display layer formed in a space formed by the first substrate and the second substrate to display an image according to an electric field applied between the first electrode and the second electrode, Wherein, the image display layer may include: a plurality of containers arranged in a space between the first substrate and the second substrate; a dielectric liquid filled in said container; white charged particles, dispersed in a dielectric liquid; and non-white charged particles, dispersed in a dielectric liquid, Wherein, the white charged particles and the non-white charged particles have different polarities. 22. The electrophoretic display device as claimed in claim 21, wherein the container is formed of a soft material such that the upper wall of the container closely fits the first optical pattern of the first electrode by pressure between the first substrate and the second substrate . 23. A method of constructing an electrophoretic display device comprising: forming an optical pattern on a surface of the first substrate; forming a first electrode of transparent material along the optical pattern on the surface of the first substrate on which the optical pattern is formed; forming a second electrode of transparent material on the surface of the second substrate; forming an image display layer on the second substrate; and bonding the first substrate and the second substrate so that an image display layer is interposed between the first substrate and the second substrate, Wherein, the image display layer includes: a plurality of containers arranged in the space between the first substrate and the second substrate; a dielectric liquid filled in said container; white charged particles, dispersed in a dielectric liquid; and non-white charged particles, dispersed in a dielectric liquid, Wherein, the white charged particles and the non-white charged particles have different polarities. 24. The method of claim 23, wherein the container is formed of a soft material such that an upper wall of the container closely fits the first optical pattern of the first electrode by pressure between the first substrate and the second substrate.

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