KR20120012742A - Electrophoretic display device - Google Patents

Electrophoretic display device Download PDF

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Publication number
KR20120012742A
KR20120012742A KR1020100075109A KR20100075109A KR20120012742A KR 20120012742 A KR20120012742 A KR 20120012742A KR 1020100075109 A KR1020100075109 A KR 1020100075109A KR 20100075109 A KR20100075109 A KR 20100075109A KR 20120012742 A KR20120012742 A KR 20120012742A
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KR
South Korea
Prior art keywords
substrate
pixel
electrode
electrophoretic display
display device
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KR1020100075109A
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Korean (ko)
Inventor
노영훈
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엘지디스플레이 주식회사
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Priority to KR1020100075109A priority Critical patent/KR20120012742A/en
Publication of KR20120012742A publication Critical patent/KR20120012742A/en

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    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/165—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on translational movement of particles in a fluid under the influence of an applied field
    • G02F1/166—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on translational movement of particles in a fluid under the influence of an applied field characterised by the electro-optical or magneto-optical effect
    • G02F1/167—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on translational movement of particles in a fluid under the influence of an applied field characterised by the electro-optical or magneto-optical effect by electrophoresis
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/133345—Insulating layers
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/133509—Filters, e.g. light shielding masks
    • G02F1/133512—Light shielding layers, e.g. black matrix
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/165—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on translational movement of particles in a fluid under the influence of an applied field
    • G02F1/1675—Constructional details
    • G02F1/1679—Gaskets; Spacers; Sealing of cells; Filling or closing of cells
    • G02F1/1681—Gaskets; Spacers; Sealing of cells; Filling or closing of cells having two or more microcells partitioned by walls, e.g. of microcup type

Abstract

The present invention, the first substrate; A gate wiring and a data wiring formed on the first substrate to define a pixel region by crossing each other with a gate insulating film interposed therebetween; A thin film transistor formed at the center of the pixel region; A pixel electrode connected to the drain electrode of the thin film transistor and formed in a first region of a central portion of the pixel region; A partition wall formed around the pixel electrode in the pixel region, the partition wall having a gradually higher height from the center portion to the outer portion thereof; A non-conductive reflective film formed over the partition wall; A second substrate facing the first substrate; A common electrode formed on an inner surface of the second substrate and having an opening corresponding to the pixel electrode; The present invention provides an electrophoretic display device including a liquid layer resumed between the first substrate and the second substrate and having black particles dispersed therein.

Description

Electrophoretic display device

The present invention relates to an electrophoretic display, and more particularly, to an electrophoretic display and a method of manufacturing the same, which have excellent gray scale expression and contrast ratio and can improve a response speed.

In general, liquid crystal displays, plasma displays, and organic field displays have become mainstream display devices. However, recently, various types of display devices have been introduced to satisfy rapidly changing consumer demands.

In particular, with the advancement and portability of the information usage environment, the company is accelerating to realize light weight, thin film, high efficiency and color video. As a part of this, research on electrophoretic display devices combining only the advantages of paper and existing display devices is being actively conducted.

The electrophoretic display device is in the spotlight as a next generation display device having an advantage of ease of portability, and unlike a liquid crystal display device, it does not require a polarizing plate, a backlight unit, a liquid crystal layer, etc., thereby reducing manufacturing costs.

Hereinafter, a conventional electrophoretic display device will be described with reference to the accompanying drawings.

1 is a view briefly showing a structure of the electrophoretic display to explain the driving principle.

As shown in the drawing, the conventional electrophoretic display device 1 includes an ink layer 57 interposed between the first and second substrates 11 and 36 and the first and second substrates 11 and 36. Include. The ink layer 57 includes a plurality of capsules 63 filled with a plurality of white pigments 59 and black pigments 61 charged through a condensation polymerization reaction.

Meanwhile, a plurality of pixel electrodes 28 connected to a plurality of thin film transistors (not shown) are formed in each pixel area (not shown) on the first substrate 11. That is, the plurality of pixel electrodes 28 are selectively applied with a positive voltage or a negative voltage, respectively. In this case, when the size of the capsule 63 including the white pigment 59 and the black pigment 61 is not constant, only a capsule 63 having a predetermined size may be selectively used.

Applying a voltage of positive or negative polarity to the ink layer 57 described above, the charged white pigments and black pigments 59 and 61 inside the capsule 63 are attracted toward opposite polarities. . That is, when the black pigment 61 moves upward, black is displayed. When the white pigment 59 moves upward, white is displayed.

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

FIG. 2 is a schematic cross-sectional view of a conventional electrophoretic display device, and the same reference numerals are used for the same names as those of FIG. 1.

As shown in the drawing, the electrophoretic display device 1 according to the related art includes an ink layer interposed between the first and second substrates 11 and 36 opposingly bonded to each other and the first and second substrates 11 and 36. (57). The ink layer 57 has a first and second adhesive layers 51 and 53 made of a transparent material, and a common electrode 55 made of a transparent conductive material therebetween, and a condensation polymerization reaction. A plurality of charged black pigments 61 and white pigments 59 are attached in the form of a film together with a plurality of capsules 63 filled therein. In addition, the black pigment 82 is positively charged and the white pigment 84 is negatively charged.

The second substrate 36 is made of transparent plastic or glass, and the first substrate 11 is mainly made of an opaque stainless material, and if necessary, a transparent plastic material or glass is used. Can be.

On the other hand, a gate wiring (not shown) and a data wiring (not shown) are formed on the first substrate 10 to vertically intersect in a matrix to define the pixel region P. The gate wiring (not shown) and data are formed on the first substrate 10. The thin film transistor Tr, which is a switching element, is formed for each pixel region P at an intersection point of the wiring (not shown).

The thin film transistor Tr overlaps the gate electrode 14 extending from the gate wiring (not shown), the gate insulating layer 16 covering the gate electrode 14, and the gate electrode 14, and the active layer ( A semiconductor layer 18 composed of 18a and an ohmic contact layer 18b, a source electrode 20 in contact with the semiconductor layer 18 and extending from a data line (not shown), and the source electrode 20 Spaced drain electrodes 22.

In addition, a passivation layer 26 including a drain contact hole 27 exposing the drain electrode 22 is formed on the entire surface of the thin film transistor Tr.

The pixel electrode 28 connected to the drain electrode 22 through the drain contact hole 27 on the passivation layer 26 corresponds to each pixel region P. As shown in FIG. The pixel electrode 28 is mainly composed of one selected from a transparent conductive material such as indium tin oxide (ITO) and indium zinc oxide (IZO).

The electrophoretic display device 1 having the above-described configuration uses a pixel light including external light including natural light or room light as a light source and is selectively applied with a positive polarity or a negative polarity by the thin film transistor Tr. (28) induces a positional change of the plurality of white pigments (59) and the black pigments (61) filled in the capsule (63) to implement an image or text.

On the other hand, although the electrophoretic display device having the above-described configuration is not shown in the figure, red, green, blue, and optionally white color filter patterns are formed on the pixel area P in front of the display area on the inner surface of the second substrate 36. Correspondingly, a color filter layer having a form of sequentially repeating may be further formed. In this case, when the color filter layer is included, an electrophoretic display device capable of realizing a full color image is provided, and when the color filter layer is not included, a monotype electrophoretic display device mainly displaying text is provided.

However, the electrophoretic display device 1 having the above-described configuration has a difficulty of realizing a video with a response time of about 200 ms, and has a low contrast ratio (typically 10: 1) and low color reproduction since the reflectance is about 40%. Due to the low gray level expressive power, there is a limitation as a display device, which is used only for a specific application such as an e-book.

Disclosure of Invention The present invention has been made to solve the above-described problem, and provides an electrophoretic display device having high contrast response characteristics, improving gray scale expression due to particle spreadability control, and improving reflection efficiency, thereby providing an excellent electrophoretic display device. The purpose.

An electrophoretic display device according to the present invention for achieving the above object, the first substrate; A gate wiring and a data wiring formed on the first substrate to define a pixel region by crossing each other with a gate insulating film interposed therebetween; A thin film transistor formed at the center of the pixel region; A pixel electrode connected to the drain electrode of the thin film transistor and formed in a first region of a central portion of the pixel region; A partition wall formed around the pixel electrode in the pixel region, the partition wall having a gradually higher height from the center portion to the outer portion thereof; A non-conductive reflecting film formed over the partition wall; A second substrate facing the first substrate; A common electrode formed on an inner surface of the second substrate and having an opening corresponding to the pixel electrode; It includes a liquid layer resumed between the first substrate and the second substrate and the black particles are dispersed.

At this time, the second substrate is characterized in that the color filter layer is formed to cover the common electrode.

In addition, a protective layer having a drain contact hole exposing the drain electrode of the thin film transistor is formed between the thin film transistor and the pixel electrode, and the barrier rib is formed on the protective layer.

The first region may have a size of 5% to 20% of the size of the pixel region, and the barrier rib may have an inclination of 10 degrees to 45 degrees with the surface of the first substrate.

In addition, the black particles are characterized in that the diameter of 1nm to 100nm, the black particles are characterized in that made of any one of carbon black, titanium oxide, copper chromite, pigment.

In addition, the liquid layer is H 2 O, or the liquid layer is characterized in that the pH 2 to PH 10 by containing an acid or a base.

In addition, the pixel electrode is made of an opaque metal, and the common electrode is made of a transparent conductive material.

In addition, an auxiliary pixel pattern branching from the pixel electrode in a wiring form is formed on the first substrate, and at one end of the pixel auxiliary pattern, a storage electrode overlapping with a gate wiring of a previous stage is provided to overlap the front gate gate. The storage electrode is characterized by forming a storage capacitor.

In addition, an auxiliary gate pattern may be formed on the first substrate of the pixel region in the form of a wiring in the gate line and connected to the gate electrode of the thin film transistor, and in the data line on the gate insulating layer of the pixel region. And an auxiliary data pattern connected to the source electrode of the thin film transistor.

In addition, the non-conductive reflecting film is characterized by consisting of an inorganic film of a multilayer structure in which a silicon oxide film and a silicon nitride film are alternated.

The electrophoretic display device according to the present invention has the effect of maximizing the reflection efficiency, thereby improving the contrast ratio compared to the conventional electrophoretic display device, and further improving the color reproducibility by forming the color filter layer inside the cell in which the particles behave.

In addition, by using the light-absorbing nanoparticles having a diameter of 1nm to 100nm as the black particles, it has a high-speed response characteristics, and has the advantage that the gray scale representation is improved compared to the conventional due to the control of particle spreading according to the voltage size between the upper and lower voltages.

1 is a view for explaining a driving principle of an electrophoretic display.
2 is a schematic cross-sectional view of a conventional electrophoretic display.
3 is a plan view of one pixel area of an electrophoretic display device according to the present invention;
4 is a cross-sectional view of a portion cut through a central portion of three consecutive pixel regions in an electrophoretic display according to the present invention;

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

3 is a plan view of one pixel area of the electrophoretic display device according to the present invention, and FIG. 4 is a view of a portion cut through the central portion of three consecutive pixel areas in the electrophoretic display device according to the present invention. It is a cross section. In this case, for convenience of description, a region in which the thin film transistor Tr, which is a switching element, is formed in each pixel region P is defined as a switching region TrA.

As illustrated, the electrophoretic display device 100 according to the present invention includes an array substrate 101 on which a thin film transistor Tr, a pixel electrode 150, and a nonconductive reflective film 156 are formed, and a transparent common electrode 165. ) And a color filter substrate 161 on which the color filter layer 170 is formed, and a solution layer 190 in which black particles having a nano-scale size interposed between the two substrates are dispersed.

The array substrate 101 includes a display area for displaying an image having a plurality of pixel areas P and a gate and a data pad part (not shown) for connecting to an external driving circuit board (not shown) outside the display area. It is divided into a non-display area (not shown).

In the display area of the array substrate 101, a plurality of gate wires 103 and data wires defining a pixel area P by crossing each other through a gate insulating film 115 at a boundary of each pixel area P. 130) is formed.

In addition, the switching region TrA defined at the center of each pixel region P is connected to the gate wiring 103 and the data wiring 130, and includes a gate electrode 108, a gate insulating film 115, The thin film transistor is a switching element including a semiconductor layer 120 including an active layer 120a of pure amorphous silicon and an ohmic contact layer 120b of impurity amorphous silicon, and source and drain electrodes 133 and 136 spaced apart from each other. Tr) is formed.

In this case, the thin film transistor Tr is formed at the center of each pixel region P according to the characteristics of the present invention. Thus, each switching region TrA is formed at the center of each pixel region P. have.

Accordingly, the gate electrode 103 of the gate wiring 103 and the thin film transistor Tr are connected by the gate auxiliary pattern 104 branched from the gate wiring 103 by the above configuration. In addition, the data auxiliary pattern 131 branched to the data line 130 is characterized in that the connection.

In addition, an organic insulating material, for example, benzocyclobutene (BCB) or photo acryl, has a thickness of about 2 μm to 4 μm on the upper portion of the thin film transistor Tr, so that the thickness of the thin film transistor Tr is increased. The first protective layer 140 is formed to have almost no influence and have a flat surface. In this case, a drain contact hole exposing the drain electrode 136 of the thin film transistor Tr is formed in the first passivation layer 140.

Although not shown, a second protective layer (eg, an inorganic insulating material, for example, silicon oxide (SiO 2 ) or silicon nitride (SiN x )) may be disposed between the thin film transistor Tr and the first protective layer 140. Not shown) may be further formed. This is because the channel characteristics may be degraded when the active layer 120a exposed between the source and drain electrodes 133 and 136 and the first protective layer 140 made of an organic insulating material are deteriorated. The second protective layer (not shown) is further formed. When the second protective layer (not shown) is formed, the drain exposing the drain electrode 136 together with the first protective layer 140 formed on the second protective layer (not shown). The contact hole 143 is formed.

Next, the drain contact hole 143 in the form of completely overlapping the switching region TrA provided in the center portion of the pixel region P on the first passivation layer 140 more precisely with the thin film transistor Tr. The pixel electrode 150 is formed in contact with the drain electrode 136 through the drain electrode 136. In this case, the pixel electrode 150 is preferably formed to have a size of about 5% to about 20% of the size of each pixel area P in a rectangular shape. In this case, it is preferable that the pixel electrode 150 is made of an opaque low-resistance metal material instead of a transparent conductive material, unlike the pixel electrode of a general electrophoretic display device. Thus, the pixel electrode 150 contributes to the reflection efficiency in each pixel region P made of opaque low-cost metal.

Meanwhile, an auxiliary pixel pattern 152 is provided on the first passivation layer 140 in the form of a wire in the pixel electrode 150, and is connected to the auxiliary pixel pattern 152 to form the pixel region P. The first storage electrode 153 is formed to correspond to the front gate line 103 disposed at the upper end. Accordingly, the second storage electrode formed of the first storage electrode 153 and the portion of the front gate gate 103 overlapping the first storage electrode 153 and the gate insulating layer 115 and the first protective layer 140 interposed between the two electrodes are disposed. The storage capacitor StgC is formed as a dielectric layer.

Next, the height of the pixel is the largest on the side of the first protective layer 140 surrounding the pixel area P, corresponding to a region other than the switching region TrA in which the pixel electrode 150 is formed, and gradually the pixel is formed. A partition wall 153 is formed in such a manner that its height gradually decreases toward the center of the pixel region P where the electrode 150 is formed. The barrier rib 153 having such a shape is characterized in that a boundary between each pixel region P, that is, a portion formed on the gate and data lines 103 and 130, contacts the color filter substrate 161 to form a spacer. At this time, the height of the partition portion forming the spacer is preferably 10㎛ 50.

In addition, the partition wall 153 having a height that gradually increases from the center portion to the outer angle with respect to the array substrate 101 surface in each pixel region P has an angle of about 10 degrees to about 45 degrees with respect to the array substrate 101 surface. It is characterized by forming.

Next, a non-conductive reflective film 156 made of a non-conductive material is formed on the partition wall 153 formed in a region other than the switching region TrA in which the pixel electrode 150 is formed. In this case, the nonconductive reflective film 156 may be formed of, for example, an inorganic film having a multilayer structure in which a silicon oxide film (not shown) having a different refractive index and a silicon nitride film (not shown) are alternated.

The non-conductive reflective film 156 is formed on the partition wall 153 formed to have a surface inclined obliquely toward the center of each pixel region P on the first passivation layer 140 in such a manner that the array substrate 101 is formed. It is formed to have an angle of about 10 degrees to 45 degrees with respect to the surface to reflect the oblique incident light to the front of the user is characterized in that it can improve the reflectance for the external light.

Next, referring to the configuration of the color filter substrate 161 positioned corresponding to the array substrate 101 having the above-described configuration, a transparent conductive material such as indium tin oxide may be formed on the inner surface of the color filter substrate 161. Alternatively, the common electrode 165 is formed in the form of an opening (oa) corresponding to the center portion of each pixel region P, that is, the pixel electrode 150 is formed as indium-ink-oxide. The common electrode 165 may be formed on the front surface of the color filter substrate 161 in the form of a plate, or may be formed on the gate line 103 or the data line 130 and formed in a stripe type. When formed as a type, it is characterized in that it is electrically connected by an auxiliary common wiring (not shown) in the non-display area.

Meanwhile, in the electrophoretic display device 100 according to the present invention, the black particles 195 are formed of the common electrode in the opening oa corresponding to the portion where the pixel electrode 150 is formed in the common electrode 165. When formed adjacent to 165, black is displayed, and when it is collected adjacent to the pixel electrode 150, full white is displayed. When the pixel electrode 150 and the common electrode 165 overlap each other, At the time when full black or full white is to be displayed, the black particles 195 may be separated into the pixel electrode 150 and the common electrode 165 to be dualized and aggregated. In this case, full black or full white may not be displayed. This is to prevent this phenomenon.

Next, the common electrode 165 having an opening oA corresponding to the pixel electrode 150 is covered, and the red, green, and blue color filter patterns R. 3, which correspond to the pixel regions P sequentially and repeatedly, are sequentially formed. A color filter layer 170 consisting of G and B) is formed.

Meanwhile, in each pixel region P surrounded by the partition wall 153 between the array substrate 101 and the color filter substrate 161 having the above-described configuration, a liquid 190 in which a plurality of black particles 195 are dispersed is provided. By being interposed, the electrophoretic display device 100 according to the present invention is completed. At this time, the black particles 195 has a size of about 1 nm to 100 nm in diameter, for example, carbon black, Titanium oxide, copper chromite, pigment is characterized in that any one.

In addition, these black particles 195 are dispersed solvent is characterized in H 2 O, the H 2 O has the black particles 195. The small amount of acidity or basic substance to speed up the movement PH 2 to PH of It is characterized by having a value of 10. Since the black particles 195 have excellent spreadability and mobility in a solvent having a base or an acid rather than a neutral solvent, the solvent in which the black particles 195 are dispersed is added with a small amount of an acidic or basic substance and thus PH 2 to PH 10. Phosphorus was formed with H 2 O.

The electrophoretic display device 100 according to the present invention having such a configuration has been experimentally found to have a response speed of several ms to 10 ms, which is 20 times higher than that of a conventional electrophoretic display device having a response speed of 200 ms. Will be improved over. In addition, although the electrophoretic display device has a reflectance of up to 40% in the conventional electrophoretic display device, the electrophoretic display device 100 according to the present invention requires the user to be obliquely arranged by the oblique arrangement of the nonconductive reflective film 156. By concentrating the light toward the viewing side and suppressing the mirror reflection of the light incident at an oblique angle, it can be seen that the color filter layer 170 has a maximum reflectance of about 50%. Accordingly, it was found that the electrophoretic display 100 according to the present invention is improved by about 10% compared to the conventional electrophoretic display in terms of reflection efficiency.

On the other hand, the contrast ratio (contrast ratio) in the conventional white to black ratio is about 10: 1, in the case of the electrophoretic display 100 according to the present invention the white to black ratio of about 20: 1 to 30: 1 It can be seen that by 2 to 3 times improved.

Hereinafter, the driving of the electrophoretic display device according to the present invention having such a configuration will be briefly described.

Referring to FIG. 4, the pixel region P in which the red color filter pattern R is formed is full black, the pixel region P in which the green color filter pattern G is formed is gray, and the blue color filter pattern B is It can be seen that the pixel region P in which the dot is formed represents a full white state, respectively.

Such driving is possible by having an appropriate voltage difference between the pixel electrode 150 and the common electrode 165.

For example, when the black particles 195 are charged with +, when full white is displayed, when − voltage is applied to the pixel electrode 150, the black particles 195 charged with + are adjacent to the pixel electrode 150. In this case, external light is incident on the portion of the pixel region P in which the non-conductive reflective film 156 is formed, is reflected by the non-conductive film, and passes through the color filter layer 170 to the outside, thereby achieving a full white state. The color will be displayed.

On the other hand, when a negative voltage is applied to the common electrode 165 with respect to the black particles 195 charged with +, the black particles 195 are thin with respect to the portion and the opening (oa) formed in the common electrode 165. In this case, the external light is absorbed by the black particles 195 to display black. On the other hand, the black particles 195 are formed in the opening oa by the screening effect. Black particles having a nano-scale size are more likely to be formed adjacent to the same layer rather than being laminated, so that they may be preferentially formed adjacent to the same layer. In this case, when the size of the opening oa is larger than the area of the common electrode 165 formed on the main surface, the screening effect is not exhibited due to the limitation of the area of the electric field.

However, in the electrophoretic display device 100 according to the present invention, the opening oa formed corresponding to the pixel electrode 150 is about 20% maximum compared to the portion of the pixel region P where the common electrode 165 is formed. By forming in the center of (P), the electric field is sufficiently acted by the common electrode 165 located nearby to express the screening effect, so that the black particles 195 form a thin film on the entire surface of the pixel region P without light leakage. It can form black.

In order to form the black particles 195 to be stacked to overcome the screening effect, an electric field having a size that can overcome the screening effect may be generated, and the black particles 195 may be disposed around the pixel electrode 150 to display full white. ) Is possible by applying a larger -voltage than -voltage applied to the common electrode 165 to display full black.

In the case of displaying gray, the black particles 195 may be dualized by applying an appropriate -voltage to each of the common electrode 165 and the pixel electrode 150.

That is, when the-voltage having the first size is applied to the common electrode 165 and the-voltage having the second size smaller than the first size is applied to the pixel electrode 150, the common electrode 165 rather than the pixel electrode 150. ) More black particles 195 are collected on the main surface, and the black particles 195 are finally collected toward the common electrode 165 by appropriately adjusting the magnitude of voltage applied to the pixel electrode 150 and the common electrode 165. By controlling the amount of external light incident from the outside is blocked by the black particles 195 collected around the common electrode 165 by controlling the amount of gray that can vary the level can be displayed.

The present invention is not limited to the above-described embodiments, and it will be apparent that various changes and modifications can be made without departing from the spirit and spirit of the present invention.

100: electrophoretic display device 101: array substrate
108 gate electrode 115 gate insulating film
120: semiconductor layer 120a: active layer
120b: ohmic contact layer 130: data wiring
131: auxiliary data pattern 133: source electrode
136: drain electrode 140: first protective layer
143: drain contact hole 150: pixel electrode
153: partition 156: non-conductive reflective film
161: color filter substrate 165: common electrode
170: color filter layer 190: liquid layer
195: black particles oa: opening
P: pixel area
R, G, B: Red, Green, Blue Color Filter Pattern
Tr: Thin Film Transistor TrA: Switching Area

Claims (13)

A first substrate;
A gate wiring and a data wiring formed on the first substrate to define a pixel region by crossing each other with a gate insulating film interposed therebetween;
A thin film transistor formed at the center of the pixel region;
A pixel electrode connected to the drain electrode of the thin film transistor and formed in a first region of a central portion of the pixel region;
A partition wall formed around the pixel electrode in the pixel region, the partition wall having a gradually higher height from the center portion to the outer portion thereof;
A non-conductive reflecting film formed over the partition wall;
A second substrate facing the first substrate;
A common electrode formed on an inner surface of the second substrate and having an opening corresponding to the pixel electrode;
A liquid layer resumed between the first substrate and the second substrate and having black particles dispersed therein
Electrophoretic display device comprising a.
The method of claim 1,
And a color filter layer formed on the second substrate to cover the common electrode.
The method of claim 1,
A protective layer having a drain contact hole exposing the drain electrode of the thin film transistor is formed between the thin film transistor and the pixel electrode.
And the barrier rib is formed on the passivation layer.
The method of claim 1,
And the first area has a size of 5% to 20% of the size of the pixel area.
The method of claim 1,
An electrophoretic display device wherein the surface of the partition wall is formed obliquely with an inclination of 10 degrees to 45 degrees with the surface of the first substrate.
The method of claim 1,
The black particles are electrophoretic display device characterized in that the diameter of 1nm to 100nm.
The method according to claim 6,
The black particles are electrophoretic display device, characterized in that made of any one of carbon black, titanium oxide, copper chromite, pigment.
The method according to claim 6,
The liquid layer is an electrophoretic display, characterized in that H 2 O.
The method according to claim 6,
The liquid layer is an electrophoretic display device characterized in that the pH 2 to PH 10 by containing an acid or base.
The method of claim 1,
The pixel electrode is made of an opaque metal, and the common electrode is made of a transparent conductive material.
The method of claim 1,
An auxiliary pixel pattern branching from the pixel electrode in a wiring form is formed on the first substrate, and one end of the pixel auxiliary pattern is provided with a storage electrode overlapping with a gate wiring of a previous stage so that the front gate gate and the storage electrode overlap with each other. An electrophoretic display, characterized by forming a storage capacitor.
The method of claim 1,
On the first substrate of the pixel region, an auxiliary gate pattern branched from the gate wiring in a wiring form and connected to the gate electrode of the thin film transistor is provided.
And an auxiliary data pattern formed on the gate insulating layer in the pixel area in the form of a wire in the data line and connected to a source electrode of the thin film transistor.
The method of claim 1,
And the nonconductive reflective film is made of an inorganic film having a multilayer structure in which a silicon oxide film and a silicon nitride film are alternately formed.
KR1020100075109A 2010-08-03 2010-08-03 Electrophoretic display device KR20120012742A (en)

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