KR20120057346A - Electrophoretic Display Device and Method for Manufacturing The Same - Google Patents

Abstract

PURPOSE: An electrophoretic display device and a manufacturing method thereof are provided to form a gate connection line and a data connection line on a gate insulating film using same metal as a data line, thereby drastically increasing the distances among a plastic board, the gate connection line, and the data connection line. CONSTITUTION: Gate lines and data lines cross each other on a board(500) by an insulating film. Gate pads and data pads apply signals to the gate lines and the data lines. Thin film transistors are formed on pixel areas where the gate lines cross the data lines. Gate connection lines(506) and data connection lines(507) are formed on the insulating film to connect the gate lines, the data lines, the gate pads, and the data pads.

Description

Electrophoretic Display Device and Method for Manufacturing The Same

The present invention relates to an electrophoretic display, and more particularly, to an electrophoretic display capable of minimizing product defects.

With the recent rapid development of semiconductor technology, as the screen size of flat panel displays increases and the weight of the flat panel displays improves, the demand for flat panel displays increases explosively.

Such a flat panel display includes a liquid crystal display (LCD), a plasma display device (PDP), a field emission display device (FED), and an electroluminescence display device (ELD). ), An electrophoresis display device (EPD), and an organic light emitting diode (OLED).

Here, the electrophoretic display device refers to a device for displaying an image using an electrophoretic phenomenon in which colored charged particles move by an electric field applied from the outside. The electrophoresis phenomenon here refers to a phenomenon in which charged particles move in a liquid by a Coulomb force when an electric field is applied to an electrophoretic dispersion liquid in which charged particles are dispersed in a liquid.

Such an electrophoretic display has bistable stability, so that the original image can be preserved for a long time even if the applied voltage is removed. In other words, the electrophoretic display device is particularly suitable for the field of the e-book which does not require the rapid replacement of the screen because it can maintain a constant screen for a long time without applying a voltage continuously. In addition, unlike the liquid crystal display device, the electrophoretic display device does not have a dependency on a viewing angle and has an advantage of providing an image that is comfortable to the eye to the extent that it is similar to paper.

On the other hand, since the electrophoretic display uses a glass substrate to withstand the high heat generated during the manufacturing process, there is a limit in providing light weight thinning and flexibility. Therefore, in recent years, electrophoretic displays using flexible materials, such as plastics, have emerged rapidly in order to maintain display performance even if they are bent like paper.

However, in manufacturing such electrophoretic display devices, plastic substrates used to have flexible properties are well bent and applied to conventional display device manufacturing equipment for processing glass substrates because of their inherent weakness to heat. For example, when the plastic film is placed on the robot arm, it may be severely bent out between the robot arms when transported by track equipment or robot, or the substrate may be accommodated when stored in a cassette. The deflection width of the substrate is larger than that of the cassette stage, so that the storage by the robot is impossible.

Therefore, the manufacturing of the electrophoretic display device using the plastic substrate has a limitation in proceeding with the array process of forming the thin film transistor using only the plastic substrate itself, unlike the manufacturing of the electrophoretic display device using the general glass substrate.

In order to overcome this problem, a plastic substrate is attached to one surface of a carrier substrate capable of conveying a rigid material such as a glass substrate to make a conveying process possible, and then a general electrophoretic display device on the plastic substrate is used. A manufacturing process of a flexible electrophoretic display device is manufactured.

Therefore, in the case of the general flexible electrophoretic display device, as shown in FIGS. 1A to 1C, after the display device 110 is formed on the plastic substrate 100, the plastic substrate 100 having the display device is formed on the carrier substrate. A process of releasing from 120 is essentially required.

However, during this separation process, as shown in FIG. 2, cracks may occur on the plastic substrate 200 in a region where the sealant is applied, thereby increasing product defects.

In addition, in a typical flexible electrophoretic display, as illustrated in FIGS. 3A and 3B, the gate pad link 300 and the data pad link 310 are formed on the plastic substrate 100 using a gate electrode forming material. As a result, the distance between the gate pad link 300 and the data pad link 310 and the plastic substrate 100 is very close.

Therefore, as shown in FIG. 4, a line defect may occur due to the opening of a data pad or a gate pad as shown in FIG. 4, resulting in a decrease in product yield and a decrease in reliability of a product. There is a problem that can be.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and an object thereof is to provide an electrophoretic display device and a method of manufacturing the same, which can prevent cracking when the plastic substrate and the carrier substrate are separated.

In addition to the aspects of the present invention mentioned above, other features and advantages of the present invention will be described below, or will be clearly understood by those skilled in the art from such description and description.

In addition, other features and advantages of the present invention may be newly understood through practice of the present invention.

An electrophoretic display device according to an aspect of the present invention for achieving the above object, the gate line and data line formed to cross each other via an insulating film on the substrate; A gate pad and a data pad for applying a predetermined signal to the gate line and the data line; A thin film transistor formed in the pixel area where the gate line and the data line cross each other; And a gate connection line and a data connection line formed on the insulating layer to connect the gate line and the data line with the gate pad and the data pad.

According to one or more exemplary embodiments, a method of manufacturing an electrophoretic display device includes: forming a second substrate on a first substrate; Forming a gate electrode and a gate line on the substrate on the second substrate; Forming an insulating film on an entire surface of the second substrate including the gate electrode and the gate line; Forming a metal film on the insulating film; And selectively etching the metal layer to form a data line, a source electrode, a drain electrode, a gate connection line, and a data connection line defining the pixel area by crossing the gate line.

According to the present invention, by forming the gate connection line and the data connection line on the gate insulating layer using the same metal as the data line, the distance between the plastic substrate and the gate connection line and the data connection line can be greatly increased, thereby It is possible to prevent the occurrence of cracks, thereby preventing the gate and data pads from being opened, thereby improving product reliability.

1 is a view schematically illustrating a separation process of a plastic substrate and a carrier substrate in a flexible display device.
2 is a view showing the occurrence of cracks during the separation process of the plastic substrate and the carrier substrate.
3A and 3B are cross-sectional views illustrating the configuration of a gate connection line and a data connection line of a typical flexible electrophoretic display.
4 shows a defect in a product due to cracking.
5 is a plan view illustrating a configuration of an electrophoretic display device according to an exemplary embodiment of the present invention.
6A is a cross-sectional view taken along the line AA ′ of FIG. 5.
6B is a cross-sectional view taken along line BB ′ of FIG. 5.
6C is a cross-sectional view taken along the line CC ′ in FIG. 5.
7A to 7J are cross-sectional views illustrating a method of manufacturing an electrophoretic display device according to an exemplary embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In describing embodiments of the present invention, when a structure is described as being formed "on" or "below" another structure, this description is intended to provide a third term between these structures as well as when the structures are in contact with each other. It is to be interpreted as including even if the structure is interposed. However, where the term "immediately above" or "immediately below" is used, it is to be construed that these structures are limited to being in contact with each other.

5 is a plan view illustrating a structure of an electrophoretic display device according to an exemplary embodiment of the present invention. FIG. 6A is a cross-sectional view taken along line AA ′ of FIG. 4, and FIG. 6B is a line BB ′ of FIG. 4. 6C is a cross-sectional view taken along the line CC ′ of FIG. 4.

As shown in FIG. 5, the electrophoretic display includes a substrate 500. In an exemplary embodiment, the substrate 500 may be a glass substrate, but a plastic substrate may be used as the substrate 500 to impart flexibility to the electrophoretic display. In this case, the plastic substrate may be a film formed of polyimide. On the other hand, since the substrate 500 is located on the side opposite to the surface on which the image is displayed, it is not necessary to have transparency.

Next, the gate lines G1, G2, and G3 and the data lines D1, D2, and D3 are formed in the display area (Active Area) on the substrate 500 to cross each other, and the gate lines G1, G2, Gate pads GP1, GP2, and GP3 for applying a gate signal to G3 and data pads DP1, DP2, and DP3 for applying a data signal to the data lines D1, D2, and D3 are provided on the substrate 500. It is formed on a non-active area of the image.

The thin film transistor T and the pixel electrode 501 are formed at the intersection of the gate lines G1, G2 and G3 and the data lines D1, D2 and D3.

In this case, the gate lines G1, G2, and G3 and the gate pads DP1, DP2, and DP3 are connected through the gate connection line 506, and the data lines D1, D2, D3, and the data pads DP1, DP2, DP3) is connected via a data connection line 507.

In the electrophoretic display device according to an exemplary embodiment, the gate connection line 506 and the data connection line 507 are formed on the gate insulating layer 508 using the same metal as the data lines D1, D2, and D3. Is formed.

That is, as shown in FIGS. 6A and 6B, a gate insulating film 508 is formed on the substrate 500 and a gate is formed on the gate insulating film 508 using the same metal as the data lines D1, D2, and D3. Forming a connection line 506 and a data connection line 507.

In one embodiment, the data lines D1, D2, D3, the source electrode 504, and the drain electrode 505 are a single layer made of silver (Ag), aluminum (Al), or an alloy thereof. In addition to such a single film, it may be composed of a multilayer film further comprising a film made of chromium (Cr), titanium (Ti), or tantalum (Ta) having excellent electrical characteristics, and thus, the gate connection line 506 and the data connection line ( 507 may also be formed using this same material.

As described above, since the present invention forms the gate connection line 506 and the data connection line 507 on the gate insulating film 508 using the same metal as the data lines D1, D2, and D3, the substrate 500 may be formed. The distance between the gate connection line 506 and the data connection line 507 increases, thereby reducing defects due to the opening of the gate pads GP1 to GP3 and the data pads DP1 to DP3.

The thin film transistor T includes a gate electrode 502 protruding from the gate lines G1, G2, and G3, a source electrode 504 protruding from the data lines D1, D2, and D3, and a source electrode ( 504 and a drain electrode 505 spaced apart from each other. Hereinafter, the structure of the electrophoretic display device including the thin film transistor T will be described in more detail with reference to FIG. 6C.

First, as shown in FIG. 6C, gate electrodes 502 and gate lines G1 to G3 are formed on the substrate 500, and a gate insulating film 508 is formed on the gate electrode 502 and gate lines G1 to. It is formed on the front surface of the substrate 500 including the G3).

In addition, a semiconductor layer 503 is formed on the gate insulating film 508 on the upper side of the gate electrode 502, and a source protruding from the data lines D1, D2, and D3 on the gate insulating film 508 and the semiconductor layer 503. An electrode 504 and a drain electrode 505 spaced apart from the source electrode 504 by a predetermined interval are formed.

Although not shown, an ohmic contact layer is further formed between the source electrode 504 and the semiconductor layer 503, and between the drain electrode 505 and the semiconductor layer 503, respectively. There may be.

In addition, a passivation layer 560 is formed on the entire surface of the substrate 500 including the gate connection line 506, the data connection line 507, the data lines D1 to D3, and the thin film transistor T. In one embodiment, the passivation layer 560 may be a nitride layer.

In addition, a dielectric layer 570 is formed on the passivation layer 560. In an embodiment, the dielectric layer 570 may be formed on a region of the passivation layer 560 corresponding to the gate lines G1 to G3, the data lines D1 to D3, and the thin film transistor T. . The dielectric layer 570 may be formed of an organic material having a low dielectric constant such as photoacryl, polyimide, or poly (4-vinylphenol), and may have a thickness of about 1 to 5 μm. .

Here, the reason for forming the dielectric layer 570 is as follows. When the pixel electrode 590 overlaps the gate lines G1 to G3, the data lines D1 to D3, and the thin film transistor T, a kickback voltage having a considerable magnitude is generated. Such kickback voltage affects the contrast ratio and the like, which results in deterioration of image quality, in particular of deterioration of still image quality. In order to minimize the kickback voltage, parasitic capacitances Cdp and Cgp respectively formed between the gate lines G1 to G3 and the pixel electrodes 590 and between the data lines D1 to D3 and the pixel electrodes 590 must be minimized. There is.

Therefore, in the present invention, in order to minimize the parasitic capacitances Cdp and Cgp, the organic material having a low dielectric constant on the region corresponding to the gate lines G1 to G3, the data lines D1 to D3, and the thin film transistor T. For example, the dielectric layer 570 is formed of photoacryl. As such, the dielectric layer 570 having a low dielectric constant is interposed between the gate lines G1 to G30 and the data lines D1 to D3 and the pixel electrode 590 to reduce the parasitic capacitances Cdp and Cgp to a considerable size. Can be. Therefore, the electrophoretic display device according to the present invention not only has a high reflectance but also can display a still image having a high contrast ratio.

Meanwhile, in the present invention, as described above, the gate connection line 506 and the data connection line 507 are formed on the same layer as the data lines D1 to D3 using the same metal as the data lines D1 to D3. To form, the gate connection line 506 and the gate lines G1 to G3 are formed through the gate insulating film 508. Therefore, in the present invention, a structure for connecting the gate connection line 506 with the gate lines G1 to G3 is required.

To this end, as shown in FIG. 6C, a portion of the gate connection line 506, the gate insulating layer 508, the passivation layer 560, and the dielectric layer 570 are etched to form the through hole H1. The gate connection line 506 is connected to the gate lines G1 to G3 using the pixel electrode 590 formed on the through hole H1.

The data connection line 507 is formed on the gate insulating film 508 using the same metal as the data lines D1 to D3, and thus may be connected to the data lines D1 to D3 without a separate connection structure. .

The pixel electrode 590 is connected to the drain electrode 754 through a through hole H2 passing through the passivation layer 560 and the dielectric layer 570, and includes a gate insulating layer 508, a gate connection line 506, and a passivation layer ( The gate connection line 506 is connected to the gate lines G1 to G3 through the through hole H1 penetrating through the 560 and the dielectric layer 570.

An electrophoretic film 600 is attached to the pixel electrode 590. The electrophoretic film 600 according to the present invention has a structure in which the base film 610, the common electrode 620, the plurality of microcapsules 630, and the adhesive layer 640 are sequentially stacked. The adhesive layer 640 of the electrophoretic film 600 is attached onto the pixel electrode 590 by a laminating process.

The base film 610 is made of glass or plastic, and the common electrode 620 is made of indium tin oxide (ITO) or indium zinc oxide (IZO). The base film 610 and the common electrode 620 should be transparent for image display.

Microcapsules 630 have electrophoretic dispersions therein. The electrophoretic dispersion includes a dielectric solvent and positively charged particles 631 and 632 respectively dispersed in the dielectric solvent. The dielectric solvent is preferably transparent to ensure reflection brightness.

Examples thereof include water, alcohol solvents, ester solvents, ketone solvents, aliphatic hydrocarbon solvents, aromatic hydrocarbon solvents, halogenated solvents, and the like, and these materials may be used alone or as a mixture. The dielectric solvent may further comprise a surfactant. The dielectric solvent may be selected to have a low viscosity in terms of ensuring high mobility of the charged particles 631 and 32.

The black particles 631 are, for example, polymers or colloids colored with black dyes such as aniline black and carbon black, and may be positively charged and used. The white particles 632 are, for example, polymers or colloids colored with white dyes such as titanium dioxide and antimony trioxide, and may be negatively charged and used. If necessary, charge control agents, dispersants, lubricants and the like may be further added in addition to these dyes.

In the present specification and drawings, for convenience of description, the present invention will be described using an electrophoretic dispersion in which positively charged black particles 631 and negatively charged white particles 632 are dispersed in a colorless dielectric solvent. The electrophoretic dispersion of the present invention is not limited thereto, and an electrophoretic dispersion in which charged white particles are dispersed in a dielectric solvent including a black dye may be used.

In this case, when the data voltage and the common voltage Vcom are applied to the pixel electrode 590 and the common electrode 620, the white particles move to the electrodes having opposite polarities, thereby displaying black and white. Conversely, electrophoretic dispersions in which charged black particles are dispersed in a dielectric solvent comprising a white dye may be used.

Although not shown in FIG. 6C, a buffer layer 740 may be formed on the substrate 500 using silicon oxide (SiO 2) or silicon nitride (SiN x). The buffer layer is intended to improve adhesion between the substrate 500 and the devices to be formed on the substrate 500 and to prevent release of organic gases or fine organic particles that may occur when the polymer material is exposed to high temperature.

Next, a manufacturing method of the electrophoretic display device according to the present invention will be described with reference to FIG. 7.

7A to 7F are flowcharts illustrating a method of manufacturing an electrophoretic display device according to an exemplary embodiment of the present invention.

First, as shown in FIG. 7A, an adhesive layer 710 is formed on a glass carrier substrate 700. The adhesive layer 710 may be formed using an inorganic material, such as amorphous silicon (a-Si) or silicon nitride (SiNx), to facilitate peeling of a plastic substrate (not shown). It can be formed as.

Next, as shown in FIG. 7B, a polymer material layer 730 such as polyimide is coated on the entire surface of the adhesive layer 710. In one embodiment, the polyimide may be applied using slit coating, spin coating, or bar coating techniques.

Thereafter, as shown in FIG. 7C, the carrier substrate 710 on which the polyimide material layer 730 is formed is positioned inside a curing apparatus such as an oven or a furnace to cure the polymer material layer 730. The polymer material layer 730 cured by the curing process becomes the plastic substrate 720.

In one embodiment, the polymer material layer 730 is maintained by placing the carrier substrate 700 on which the polymer material layer 730 is formed in the curing apparatus and then maintaining the polymer material layer 730 for 20 to 120 minutes in a temperature atmosphere of 150 ° C to 300 ° C. It can be cured.

In addition, the plastic substrate 720 is preferably formed so that the thickness is 50㎛ to 300㎛. If the thickness is thinner than this, the plastic substrate 720 and the carrier substrate 700 may have a breakage in the separation process, and if the thickness is thicker than this, the thickness of the glass material constituting the general display device becomes thinner. Because you can back.

Next, as shown in FIG. 7D, the buffer layer 740 is formed by depositing silicon oxide (SiO 2) or silicon nitride (SiN x) on the entire surface of the plastic substrate 720. As described above, the buffer layer 740 may improve adhesion between the plastic substrate 720 and the display element to be formed on the plastic substrate 620 and may be formed of organic gas or fine organic particles that may occur when the polymer material is exposed to high temperature. Since it is for preventing the release, it can be formed selectively.

In this case, the buffer layer 740 may be formed of a single layer of silicon oxide or silicon nitride only, or may be formed of a double layer structure of silicon oxide / silicon nitride or silicon nitride / silicon oxide.

Next, as shown in 7e, gate electrodes 751 and gate lines G1 to G3 are formed, and a gate insulating film 752 is formed on the gate electrodes 751 and gate lines. Thereafter, after the semiconductor layer 754 is formed on the gate insulating layer 752, the source electrode 756 partially overlapping the semiconductor layer 754, the drain electrode 758 spaced apart from the source electrode 756, A data line D1 to D3 connected to the source electrode 756 and the drain electrode 758, a gate connection line 759 to connect the gate line G1 to G3, and a gate pad (not shown), and A data connection line (not shown) for connecting the data lines D1 to D3 and a data pad (not shown) is formed.

That is, in the present invention, the gate and data pads (not shown) are separated in separating the plastic substrate 720 from the carrier substrate 700 by increasing the distance between the gate connection line 759 and the data connection line and the plastic substrate 720. In order to prevent the opening of the gate line 759 and the data connection line, the gate insulating line 752 is formed on the gate insulating layer 752 by using the same metal as the data lines D1 to D3 when the data lines D1 to D3 are formed. To form.

On the other hand, the gate electrode 751, the gate insulating film 752, the semiconductor layer 754, the source electrode 756, and the drain electrode 758 form the thin film transistor Tr which is the switching element SW.

An ohmic contact layer (not shown) may be further formed between the source electrode 756 and the semiconductor layer 754, and between the drain electrode 758 and the semiconductor layer 754.

Subsequently, as shown in FIG. 7F, a protective film 760 and a dielectric layer 762 are formed on the entire surface of the plastic substrate 720.

Subsequently, as shown in FIG. 7G, a portion of the passivation layer 760, the dielectric layer 762, the gate connection line 759, and the gate insulating layer 752 are removed to form the through hole H1. A portion of the protective film 760 and the dielectric layer 762 are removed to form H2).

Subsequently, as shown in FIG. 7H, the gate connection line 759 and the gate lines G1 to G3 are connected to each other through the through hole H1, and the drain electrode 768 of the thin film transistor T is connected. And a pixel electrode 770 connected to each other are formed on the dielectric layer 762.

Subsequently, as shown in FIG. 7I, the electrophoretic display device is completed by attaching the adhesive layer 788 of the electrophoretic film 780 onto the pixel electrode 770. In this case, as shown in FIG. 7I, the electrophoretic film 780 includes a base film 782 of a flexible material, a common electrode 784, a plurality of microcapsules 786, and an adhesive layer 788. do.

Thereafter, as shown in FIG. 7J, the plastic substrate and the carrier substrate are separated by irradiating a laser beam on the rear surface of the carrier substrate. Subsequently, although not shown, an electrophoretic display device is completed by applying a sealant to each unit cell and then applying silicon to the entire surface of the plastic substrate 720.

Although not shown in FIG. 7, the carrier substrate 700 on which the flexible substrate 720 is formed is cut for each pixel region to form a unit cell, and COF (Chip On Film) and FPCB (Flexible Printed) are formed on each unit cell. The process may further include attaching a circuit board.

Those skilled in the art to which the present invention pertains will understand that the above-described present invention can be implemented in other specific forms without changing the technical spirit or essential features.

For example, in the above-described embodiment, the present invention is described as being applied to an electrophoretic display device using a microcapsule, but in the modified embodiment, the present invention may be applied to an electrophoretic display device using a partition wall.

Therefore, it is to be understood that the embodiments described above are exemplary in all respects and not restrictive. The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within the scope of the present invention do.

500: substrate 501: pixel electrode
502: gate electrode 504: source electrode
505: drain electrode 506: gate connection line
507: data connection line

Claims (10)

A gate line and a data line formed to intersect each other via an insulating film on the substrate;
A gate pad and a data pad for applying a predetermined signal to the gate line and the data line;
A thin film transistor formed in the pixel area where the gate line and the data line cross each other; And
And a gate connection line and a data connection line formed on the insulating layer to connect the gate line and the data line with the gate pad and the data pad. The method of claim 1,
And a connection line electrically connecting the gate line and the gate connection line. The method of claim 1,
And the gate connection line and the data connection line are formed of the same metal as the data line. The method of claim 1,
The substrate is an electrophoretic display device, characterized in that the film formed using a polyimide. The method of claim 1,
A protective film formed on an entire surface of the substrate including the gate line and the data line;
A dielectric layer formed on the protective film;
A pixel electrode formed on the dielectric layer; And
And an electrophoretic film attached to the pixel electrode. Forming a second substrate on the first substrate;
Forming a gate electrode and a gate line on the substrate on the second substrate;
Forming an insulating film on an entire surface of the second substrate including the gate electrode and the gate line;
Forming a metal film on the insulating film; And
And selectively etching the metal layer to form a data line, a source electrode, a drain electrode, a gate connection line, and a data connection line defining the pixel area by crossing the gate line. Method of preparation. The method of claim 6,
Forming a protective film on an entire surface of the second substrate;
Forming a dielectric layer on the passivation layer;
Partially removing the passivation layer and the dielectric layer to form a first hole, and partially removing the insulating layer, the gate connection line, the passivation layer, and the dielectric layer to form a second hole;
Forming a pixel electrode connected to the drain electrode through the first hole and connecting the gate connection line and the gate line through the second hole on the dielectric layer;
Attaching an electrophoretic film including microcapsules containing charged particles on the pixel electrode; And
And separating the second substrate from the first substrate. The method of claim 6,
And the first substrate is made of glass, and the second substrate is formed of polyimide. The method of claim 6, wherein prior to forming the second substrate,
And forming an inorganic adhesive layer on the first substrate to separate the second substrate. The method of claim 6, wherein prior to forming the gate electrode and the gate line,
And forming a buffer layer formed of an inorganic insulating material on the second substrate.

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