KR20110075186A - Electrophoretic display device - Google Patents

Abstract

PURPOSE: An electrophoresis display device is provided to improve optical efficiency and reduce a production cost and consumption power. CONSTITUTION: An electrophoresis display device includes a lower substrate(110), a first electrode(112), a black matrix(114), an upper substrate(120), a second electrode(122), a backlight unit(190), an optical conversion particle(130). The lower substrate is defined as a plurality of sub pixel. The first electrode is formed on the lower substrate. A black matrix is formed on the lower substrate between the first electrode. The upper substrate faces the lower substrate. The second electrode is formed on the upper substrate of the location facing the black matrix. A black unit generates the light which is arranged in the lower substrate. The optical conversion particle with a positive or a negative charge and is formed between the lower substrate and the upper substrate.

Description

Electrophoretic display {ELECTROPHORETIC DISPLAY DEVICE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophoretic display, and more particularly, to an electrophoretic display capable of improving light efficiency and reducing production cost and power consumption.

In recent years, with the development of the information society, various types of demands on display devices have increased, such as liquid crystal display devices (LCDs), plasma display panels (PDPs), and field emission displays. Research on flat panel display devices such as devices (FED), organic electroluminescent emitting devices (OLEDs), and electrophoretic display devices (EPDs) is being actively conducted.

Among them, an electrophoretic display is an image display device using a phenomenon in which colloidal particles move to either polarity when a pair of electrodes to which voltage is applied is immersed in a colloidal solution. And low power consumption, which is expected to attract attention as an electric paper.

As shown in FIG. 1, the electrophoretic display device includes an electrophoretic body 30 interposed between the lower substrate 10 having the lower electrode 14 and the upper substrate 20 having the upper electrode 24 formed thereon. Has a structure. R, G, and B color filter layers 22 are formed between the upper electrode 24 and the upper substrate 20 to realize color, and the drive array 12 is disposed between the lower electrode 14 and the lower substrate 20. Is formed to apply an electric potential to the electrode.

When a potential is applied to the lower electrode 14 and the upper electrode 24, the white or black charged particles in the electrophoretic body 30 move to one electrode or the other, whereby an image image is realized. .

The electrophoretic display uses the color filter layer 22 to implement an image image because the electrophoretic body 30 expresses only white or black. When the color filter layer 22 is used, transmittance and reflection efficiency are reduced. In particular, when using a flexible substrate, it is technically difficult to implement a color filter layer on the flexible upper substrate. In addition, it is difficult to accurately match the size of the capsule and the size of the pixel of the electrophoretic body 30.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide an electrophoretic display device capable of improving light efficiency and reducing production cost and power consumption.

An electrophoretic display according to the present invention includes a lower substrate defined by a plurality of sub pixels, a first electrode formed on the lower substrate, a black matrix formed on the lower substrate between the first electrodes, and the lower substrate. An upper substrate opposed to the second substrate, a second electrode formed on the upper substrate at a position opposite to the black matrix, a backlight unit disposed below the lower substrate to generate light, and formed between the lower substrate and the upper substrate And light converting particles having a negative or positive charge.

When the light conversion particle has a negative charge, when a positive voltage is applied to the first electrode and a negative voltage is applied to the second electrode, R, G, Or a B image is displayed.

When the light conversion particle has a positive charge, when a positive voltage is applied to the first electrode and a negative voltage is applied to the second electrode, black is displayed in the transmission mode and the reflection mode.

The electrophoretic display according to the present invention further includes Hexane, toluene, chloroform or water for improving the fluidity of the light conversion between the lower substrate and the upper substrate.

The first electrode and the second electrode are formed of a transparent conductive material.

The electrophoretic display according to the present invention further includes black particles having a polarity opposite to that of the light conversion particles.

In this case, the first electrode is formed of a transparent conductive material, and the second electrode is formed of an opaque conductive material.

An electrophoretic display device according to still another embodiment of the present invention includes a lower substrate defined by a plurality of sub pixels, a first electrode formed on the lower substrate, an upper substrate facing the lower substrate, and an upper substrate. A second electrode to be formed, a backlight unit disposed under the lower substrate to generate light, and a light conversion particle having a negative or positive charge between the lower substrate and the upper substrate and a polarity opposite to the light conversion particle; Black particles.

The first electrode is formed on the entire subpixel of the lower substrate with a transparent conductive material, and the second electrode is formed on the entire subpixel of the upper substrate with a transparent conductive material.

Herein, when the light conversion particle has a negative charge, when a positive voltage is applied to the first electrode and a negative voltage is applied to the second electrode, the light conversion particle and the black particle in the transmission mode and the reflection mode. When the light conversion particle has a positive charge or when the light conversion particle has a positive charge, when a positive voltage is applied to the first electrode and a negative voltage is applied to the second electrode, black is displayed in the transmission mode and a reflection mode When the R, G, or B image is displayed, or when the light conversion particle has a negative charge, a negative voltage is applied to the first electrode and a positive voltage is applied to the second electrode, and thus black in the transmission mode. Is displayed and an R, G, or B image is displayed in the reflection mode, or when the light conversion particle has a positive charge, a negative voltage is applied to the first electrode and a positive voltage is applied to the second electrode. When The mode and the reflection mode are displayed in black by the light conversion particles and the black particles.

Since the electrophoretic display according to the present invention displays an image in a color emitted by the light conversion particles, it is not necessary to use a color filter layer, thereby improving color reproduction with high color purity as well as transmittance and reflection efficiency.

In addition, the present invention can increase the visibility from the outside in combination with the transmission and reflection mode, the structure is simple, it can reduce the production cost and power consumption.

Hereinafter, an electrophoretic display device according to the present invention will be described in detail with reference to the accompanying drawings.

2A and 3B are cross-sectional views illustrating an electrophoretic display device according to a first embodiment of the present invention, and FIGS. 2A and 2B are images in a reflection mode of the electrophoretic display device according to the first embodiment of the present invention. 3A and 3B are cross-sectional views illustrating an image display state in a transmissive mode of an electrophoretic display device according to a first embodiment of the present invention.

The electrophoretic display according to the present invention includes a lower substrate 110 having a plurality of sub pixels, an upper substrate 120 facing the lower substrate 110, and a lower substrate 110 between the lower substrate 110 and the upper substrate 120. It includes the formed light conversion particles 130 and the backlight unit 190.

The first electrode 112, the black matrix 114, and the partition wall 152 for separating the subpixels are formed on the lower substrate 110. The second electrode 122 for forming an electric field and the UV barrier film 140 for blocking light are formed on the upper substrate 120.

The lower substrate 110 and the upper substrate 120 are known transparent substrates used in electrophoretic displays, and glass or transparent plastic films are used.

The first electrode 112 is formed on the lower substrate 110 to be spaced apart from each other with the black matrix 114 interposed therebetween. As the constituent material of the first electrode 112, any conductive metal material may be used without limitation. For example, indium tin oxide (ITO), tin oxide (TO), indium zinc oxide (IZO), and indium tin zinc (Indium Tin Zinc) may be used as the first electrode 112. Oxide: ITZO) or a combination thereof may be used.

The black matrix 114 is formed on the lower substrate 110 between the first electrodes 112 at positions opposite to the second electrode 122 of the upper substrate 120. The partition wall 152 separates the lower substrate 110 in units of sub-pixels, and also forms a gap between the lower substrate 110 and the upper substrate 120. The partition wall 152 may be formed of a known insulating material.

The second electrode 122 formed on the upper substrate 120 is formed to face the black matrix 114 of the lower substrate 110. That is, the second electrode 122 is formed to overlap the black matrix 114 when looking at the upper substrate 120. The constituent material of the second electrode 122 is not particularly limited as long as it is a conductive opaque metal material.

The UV barrier film 140 is formed on the front surface of the upper substrate 120 to block light from the backlight unit 190 disposed below the lower substrate 110 from being emitted through the upper substrate 120. do.

The light conversion particle 130 is a particle that absorbs a specific light wavelength region from the outside or the backlight unit 190 and converts and emits the light to a wavelength of the visible light region, and between the lower substrate 110 and the upper substrate 120. A plurality of sub pixels are formed. The light conversion particle 130 emits an R, G, or B color in each sub pixel. For this purpose, the light conversion particles 130 may be R light conversion particles, G light conversion particles or B light conversion particles. The emission color of the light conversion particle 130 is not limited to R, G, B.

6A and 6B, the photoconversion particle 130 has a ligand attached to a surface thereof to have a positive charge or a negative charge. A solvent such as hexane, toluene, chloroform, and water may be further included between the lower substrate 110 and the upper substrate 120 to improve the fluidity of the light conversion particles 130.

Referring to FIG. 2A, when the light conversion particle 130 has a negative charge in the reflection mode in which the backlight unit 190 is off, a positive voltage is applied to the first electrode 112 and the second electrode ( When a negative voltage is applied to the 122, the light conversion particle 130 moves to the first electrode 112 having a polarity opposite to that of the light conversion particle 130. Accordingly, the light conversion particle 130 absorbs and converts external light to emit R, G or B light to the upper substrate 120 to display an image.

Although not shown in the drawing, when the light conversion particles have a positive charge in the reflective mode in which the backlight unit is off, when the positive voltage is applied to the first electrode and the negative voltage is applied to the second electrode, the light conversion particles are applied. Moves to the polarized second electrode opposite to its polarity. Therefore, the light conversion particles cannot absorb external light by blocking the second electrode so that the upper substrate displays black.

Referring to FIG. 2B, when the light conversion particle 130 has a negative charge in the reflection mode in which the backlight unit 190 is off, a negative voltage is applied to the first electrode 112 and the second electrode ( When a positive voltage is applied to the 122, the light conversion particle 130 moves to the second electrode 122 having a polarity opposite to that of the light conversion particle 130. Therefore, since the light conversion particles 130 cannot absorb external light by blocking the second electrode 122 and are blocked by the second electrode 122 even when emitting light, the black substrate is displayed on the upper substrate 120. .

Although not shown in the drawing, when the light conversion particles have a positive charge in the reflection mode in which the backlight unit is off, a negative voltage is applied to the first electrode, and when the positive voltage is applied to the second electrode, the light conversion particles are applied. Moves to a polarized first electrode opposite to its polarity. Accordingly, the light conversion particles absorb and convert external light to emit R, G or B light to the upper substrate to display an image.

Referring to FIG. 3A, when the light conversion particle 130 has negative charge in the transmissive mode in which the backlight unit 190 is on, a positive voltage is applied to the first electrode 112 and the second electrode When a negative voltage is applied to the 122, the light conversion particle 130 moves to the first electrode 112 having a polarity opposite to the polarity thereof. Accordingly, the light conversion particle 130 absorbs and converts light of the backlight unit 190 to emit R, G, or B light to the upper substrate 120 to display an image.

Although not shown in the drawings, when the light conversion particles have a positive charge in the transmissive mode when the backlight unit is on, a positive voltage is applied to the first electrode and a negative voltage is applied to the second electrode. Moves to the second electrode. Therefore, the light emission color of the light conversion particles is blocked by the second electrode, and the light of the backlight unit is blocked by the UV barrier film, so that black is displayed on the upper substrate.

Referring to FIG. 3B, when the light conversion particle 130 has a negative charge in the transmission mode in which the backlight unit 190 is on, a negative voltage is applied to the first electrode 112 and the second electrode ( When a positive voltage is applied to the 122, the light conversion particle 130 moves to the second electrode 122 having a polarity opposite to that of the light conversion particle 130. Therefore, the light emission color of the light conversion particle 130 is blocked by the second electrode 122, and the light of the backlight unit 190 is blocked by the UV barrier film 140, so that a black image on the upper substrate 120 Is displayed.

Although not shown in the drawing, when the light conversion particles have a positive charge in the transmissive mode in which the backlight unit is on, a negative voltage is applied to the first electrode, and the light conversion particles are applied when the positive voltage is applied to the second electrode. Move to the first electrode. Therefore, the light conversion particles absorb and convert light of the backlight unit to emit R, G or B light to the upper substrate to display an image.

As such, the electrophoretic display device according to the present invention displays an image in a color emitted by the light conversion particles 130, and thus does not require the use of a color filter layer. Therefore, the present invention can improve the transmittance and the reflection efficiency, and can improve the color reproducibility with high color purity.

In addition, the electrophoretic display device according to the present invention can increase the visibility from the outside by using both the transmission and reflection mode, and can reduce the production cost and power consumption due to the simple structure. In addition, the light conversion particle 130 according to the present invention is a liquid is advantageous to the flexible.

Meanwhile, the backlight unit 190 includes a UV lamp 192 for generating light and a light guide plate 194 for widely distributing the light generated by the UV lamp 192. The wavelength band of the UV lamp 192 is 400 nm or less.

4A and 4B, an electrophoretic display device according to a second exemplary embodiment of the present invention may include a lower substrate 210 having a plurality of sub pixels, an upper substrate 220 facing the lower substrate 210, and a lower substrate 210. The light conversion particles 230 and the black particles 260 formed between the lower substrate 210 and the upper substrate 220, on the backlight unit 290 and the upper substrate 220 disposed under the lower substrate 210. It includes a UV barrier film 240 formed on.

The first electrode 112 for forming an electric field and the partition 252 for separating sub pixels are formed on the lower substrate 210. The second electrode 222 for forming an electric field and the UV barrier film 240 for blocking light are formed on the upper substrate 220.

The first electrode 212 is formed for each sub pixel on the lower substrate 210. As the constituent material of the first electrode 212, any conductive metal material may be used without limitation. For example, indium tin oxide (ITO), tin oxide (TO), indium zinc oxide (IZO), and indium tin zinc (Indium Tin Zinc) may be used as the first electrode 212. Oxide: ITZO) or a combination thereof may be used. The partition 252 may be formed of a known insulating material.

The second electrode 222 is formed on the upper substrate 220 to face the first electrode 212. As the constituent material of the second electrode 222, any conductive metal material may be used without limitation. For example, indium tin oxide (ITO), tin oxide (TO), indium zinc oxide (IZO), and indium tin zinc (Indium Tin Zinc) may be used as the second electrode 222. Oxide: ITZO) or a combination thereof may be used.

The UV barrier film 240 is formed on the front surface of the upper substrate 220 to block the light from the backlight unit 290 disposed below the lower substrate 210 from being emitted through the upper substrate 220. do.

The backlight unit 290 includes a UV lamp 292 for generating light and a light guide plate 294 for widely distributing the light generated by the UV lamp 292. The wavelength band of the UV lamp 292 is 400 nm or less.

The light conversion particle 230 is a particle that absorbs a specific light wavelength region and emits light by converting light into a wavelength of a visible light region. A plurality of light conversion particles 230 are formed for each sub-pixel between the lower substrate 210 and the upper substrate 220.

The light conversion particle 230 emits an R, G or B color in each sub pixel. For this purpose, the light conversion particles 230 may be R light conversion particles, G light conversion particles or B light conversion particles. The emission color of the light conversion particle 230 is not limited to R, G, B. A solvent such as hexane, toluene, chloroform, and water may be further included between the lower substrate 210 and the upper substrate 220 to improve the fluidity of the light conversion particles 230.

The photoconversion particle 230 has a positive or negative charge by attaching a ligand to the surface as shown in FIGS. 5A and 5B. The black particles 260 have polarities opposite to those of the light conversion particles 230. That is, when the light conversion particle 230 has a positive charge, the black particles 260 have a negative charge, and when the light conversion particle 230 has a negative charge, the black particles 260 may have a positive charge. Have

Referring to FIG. 4A, when the light conversion particle 230 has a negative charge and the black particle 260 has a positive charge in the reflection mode in which the backlight unit 290 is off, the first electrode 212 may have a negative charge. When a negative voltage is applied to the second electrode 222 and a positive voltage is applied to the second electrode 222, the light conversion particles 230 move to the second electrode 222 having a polarity opposite to that of the second electrode 222, and the black particles ( 260 moves to the first electrode 212. Accordingly, the light conversion particle 230 absorbs and converts external light to emit R, G, or B light to the upper substrate 220 to display an image.

Referring to FIG. 4B, when the light conversion particle 230 has a negative charge and the black particle 260 has a positive charge in the reflection mode in which the backlight unit 290 is off, the first electrode 212 is provided. When a positive voltage is applied to the second electrode 222 and a negative voltage is applied to the second electrode 222, the light conversion particles 230 move to the first electrode 212 having a polarity opposite to that of the second electrode 222. 260 moves to the second electrode 222. Accordingly, the light conversion particles 230 may not emit external light due to blocking of the black particles 260, or may not emit light, or the black particles 260 may be seen to display a black image on the upper substrate 120.

Although not shown in the drawing, when the light conversion particle has a positive charge and the black particle has a negative charge in the transmissive mode in which the backlight unit is on, as described above, a negative voltage is applied to the first electrode. When a positive voltage is applied to the second electrode, the light conversion particles move to the first electrode having a polarity opposite to that of the polarity, and the black particles move to the second electrode. Therefore, even if the light conversion particle absorbs and converts light of the backlight unit to emit R, G or B light, it is blocked by the black particles to display black.

When the light conversion particle has a positive charge and the black particle has a negative charge in the transmissive mode with the backlight unit on, a positive voltage is applied to the first electrode and a negative voltage is applied to the second electrode. The converting particles move to the second electrode having a polarity opposite to their polarity, and the black particles move to the first electrode. Therefore, the light of the backlight unit is blocked by the black particles to display black.

In contrast, when the light conversion particle has a negative charge and the black particle has a positive charge in the transmission mode with the backlight unit turned on, a negative voltage is applied to the first electrode and a positive voltage is applied to the second electrode. When applied, the light conversion particles move to the second electrode, and the black particles move to the first electrode. Therefore, the light of the backlight unit is blocked by the black particles so that the upper substrate displays black.

In addition, when the light conversion particle has a negative charge and the black particle has a positive charge in the transmission mode with the backlight unit turned on, a positive voltage is applied to the first electrode and a negative voltage is applied to the second electrode. When the light conversion particles move to the first electrode, the black particles move to the second electrode. Therefore, the light of the backlight unit is blocked by the black particles so that the upper substrate displays black.

As described above, the electrophoretic display device according to the present invention controls the light of the external light or the backlight unit and the electric fields of the first electrode and the second electrode so as to be opposite to the light conversion particles 230 having a positive charge or a negative charge. An image is displayed by moving the position of the black particle 260 which has polarity.

Therefore, the electrophoretic display device according to the present invention does not need to use a color filter layer, thereby improving transmittance and reflection efficiency, and improving color reproducibility with high color purity. In addition, the combination of the transmission and reflection mode can increase the visibility from the outside, the simple structure can reduce the production cost and power consumption.

The electrophoretic display device according to the third embodiment of the present invention further includes black particles having a polarity opposite to the light conversion particles in the structure of the electrophoretic display device according to the first embodiment.

As shown in the first embodiment, the electrophoretic display according to the third embodiment also moves the black particles to the second electrode when the light conversion particles move to the first electrode, and moves the black particles to the second electrode when the light conversion particles move to the second electrode. The particles move to the first electrode, thereby adjusting the image display.

The above-described techniques represent presently preferred embodiments, and the present invention is not limited to the above-described embodiments and the accompanying drawings. Modifications and other uses of the embodiments will be apparent to those skilled in the art, and such changes and other uses are defined by the scope of the claims contained within or appended to the spirit of the invention.

1 is a cross-sectional view of a conventional electrophoretic display device.

2A and 2B are cross-sectional views illustrating an image display state in a reflection mode of an electrophoretic display device according to a first embodiment of the present invention.

3A and 3B are cross-sectional views illustrating an image display state in a transmissive mode of an electrophoretic display device according to a first embodiment of the present invention.

4A and 4B are cross-sectional views illustrating an image display state in a reflection mode of an electrophoretic display device according to a second exemplary embodiment of the present invention.

5A and 5B are views for explaining the light conversion particles of the present invention.

<< Explanation of symbols for main part of drawing >>

110 and 210: lower substrate 112 and 212: first electrode

114, 214: Black matrix 120, 220: Upper substrate

122, 222: second electrode 130, 230: light conversion particles

140, 240: UV barrier film 260: black particles

190, 290: backlight unit

Claims (10)

A lower substrate defined by a plurality of sub pixels; A first electrode formed on the lower substrate; A black matrix formed on the lower substrate between the first electrodes; An upper substrate facing the lower substrate; A second electrode formed on the upper substrate at a position opposite to the black matrix; A backlight unit disposed under the lower substrate to generate light; And And an optical conversion particle formed between the lower substrate and the upper substrate and having a negative or positive charge. The light conversion particle of claim 1, wherein when the light conversion particle has a negative charge, a positive voltage is applied to the first electrode and a negative voltage is applied to the second electrode. An electrophoretic display device, wherein an R, G, or B image is displayed. The method of claim 1, wherein when the light conversion particle has a positive charge, black is displayed in a transmission mode and a reflection mode when a positive voltage is applied to the first electrode and a negative voltage is applied to the second electrode. Electrophoretic display device characterized in that. The electrophoretic display of claim 1, further comprising Hexane, toluene, chloroform, or water for improving the fluidity of the light conversion between the lower substrate and the upper substrate. The electrophoretic display of claim 1, wherein the first electrode and the second electrode are formed of a transparent conductive material. The electrophoretic display of claim 5, further comprising black particles having a polarity opposite to the light conversion particles. The method of claim 1, wherein the first electrode is formed of a transparent conductive material, And the second electrode is formed of an opaque conductive material. A lower substrate defined by a plurality of sub pixels; A first electrode formed on the lower substrate; An upper substrate facing the lower substrate; A second electrode formed on the upper substrate; A backlight unit disposed under the lower substrate to generate light; And And a light conversion particle having a negative or positive charge between the lower substrate and the upper substrate and black particles having a polarity opposite to the light conversion particle. The method of claim 8, wherein the first electrode is formed on the entire front side of the sub pixel of the lower substrate using a transparent conductive material. And the second electrode is formed on the entire surface of the sub pixel of the upper substrate with a transparent conductive material. The light conversion particle of claim 8, wherein when the light conversion particle has a negative charge, a positive voltage is applied to the first electrode and a negative voltage is applied to the second electrode. And black by the black particles, or When the photoconversion particle has a positive charge, when a positive voltage is applied to the first electrode and a negative voltage is applied to the second electrode, black is displayed in the transmission mode and R, G, or B in the reflection mode. An image is displayed, When the light conversion particle has a negative charge, when a negative voltage is applied to the first electrode and a positive voltage is applied to the second electrode, black is displayed in the transmission mode and R, G, or B in the reflection mode. An image is displayed, When the light conversion particles have a positive charge, when a negative voltage is applied to the first electrode and a positive voltage is applied to the second electrode, the light conversion particles and the black particles are used in the transmission mode and the reflection mode. Electrophoretic display device characterized in that shown in black.

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