KR20130073664A - Display device - Google Patents

Abstract

PURPOSE: A display device is provided to show a property of the level equivalent to that a short-circuit is not generated even in the short-circuit generation in a rear side indium tin oxide (ITO) by forming a bypass-line on the rear side ITO. CONSTITUTION: A liquid crystal panel is formed by interposing a liquid crystal layer between a color filter substrate (140) and a thin film transistor (TFT) array substrate. A ground pad (185) is formed on the TFT array substrate. A polarizing plate is formed on the color filter substrate. A rear side indium tin oxide (ITO) (160) is formed on the front side of the polarizing plate. A bypass-line (165) is formed on at least one edge of the rear side ITO on the rear side ITO. An Ag dot (180) contacts the bypass-line, the rear side ITO and the ground pad.

Description

Display device {DISPLAY DEVICE}

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a display device, and more particularly, to a display device capable of improving transmittance and reliability by forming an auxiliary line in a rear ITO.

2. Description of the Related Art Recently, various portable electronic devices such as a mobile phone, a PDA, and a notebook computer have been developed. Accordingly, there is a growing need for a flat panel display device for a light and small-sized flat panel display device. As such a flat panel display device, a liquid crystal display, a plasma display panel, a field emission display, and the like have been actively studied, but the mass production technology, the ease of driving means, Due to its implementation, liquid crystal display devices are now in the limelight.

In the liquid crystal display device, there are various display modes such as TN and VA depending on the arrangement of the liquid crystal molecules, but a TN mode having a high response speed and a low driving voltage is widely used. This TN mode liquid crystal display is oriented substantially perpendicular to the substrate when voltage is applied to the liquid crystal molecules aligned horizontally with the substrate. Therefore, there is a problem that the viewing angle is narrowed when a voltage is applied due to refractive anisotropy of liquid crystal molecules.

In order to solve such a viewing angle problem, an in-plane switching mode liquid crystal display device having a wide viewing angle characteristic has been used.

1 is a cross-sectional view showing a cross section of a conventional liquid crystal display device, and Fig. 2 is a plan view showing a plane of Fig.

1, a conventional liquid crystal display device 1 includes a TFT array substrate 3 on which a thin film transistor, a common electrode, a pixel electrode and a driving IC 4 are formed, a color filter A liquid crystal panel LP including a substrate 5 and a liquid crystal layer (not shown) interposed therebetween is provided. A bottom polarizing plate 7 is provided below the TFT array substrate 3 and a rear ITO 13 is provided on the top surface of the color filter substrate 5. An upper polarizing plate 8 is provided on the rear ITO 13 do. At the edges of the TFT array substrate 3 and the color filter substrate 5 bonded together are Ag dots (not shown) connecting the rear surface ITO 13 of the color filter substrate 5 and the ground pads 9 of the TFT array substrate 3 10 are formed.

In the conventional liquid crystal display device 1, contraction and relaxation occur in the polarizing plates 7 and 8 under high temperature or high temperature and high humidity conditions. At this time, the rear ITO 13 adjacent to the upper polarizer 8 also contracts and relaxes do. Here, when the thickness of the rear ITO 13 is thin, short-circuiting of the rear ITO 13 occurs as shown in FIG. 2, and resistance of the rear ITO 13 is increased.

The present invention provides a display device capable of improving transmittance and reliability by forming an auxiliary line in a rear ITO.

In order to achieve the above object, a display device according to an embodiment of the present invention includes a liquid crystal panel interposed between a color filter substrate and a TFT array substrate, a ground pad formed on the TFT array substrate, A backing ITO formed on the front surface of the polarizing plate, an auxiliary line formed on at least one edge of the backing ITO on the backing ITO, and Ag dots contacting the backing line, the backing ITO, and the ground pad .

The auxiliary line may be made of the same material as the Ag dots.

The auxiliary line may be located on at least one edge of the backside ITO connected to the Ag dot.

The auxiliary line may be located at all edges of the back ITO.

The auxiliary line may be located outside the active area in which the image is displayed.

The display device according to an embodiment of the present invention has an advantage that the auxiliary line is formed on the rear ITO so that even if the rear ITO is short-circuited, the display can exhibit the same level of characteristics as no short circuit has occurred. Therefore, the reliability of the display device can be improved. In addition, there is an advantage that the thickness of the rear ITO can be reduced to improve the transmittance.

1 is a cross-sectional view showing a cross section of a conventional liquid crystal display device.
Fig. 2 is a plan view showing the plane of Fig. 1; Fig.
3 is a plan view showing a liquid crystal display device of the present invention.
4 is a cross-sectional view taken along line I-I 'of FIG. 3;
5 is a plan view of a liquid crystal display according to an embodiment of the present invention.
6 is a cross-sectional view taken along line II-II 'of FIG. 5;
7 to 9 are plan views illustrating a liquid crystal display device according to another embodiment of the present invention.

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

FIG. 3 is a plan view of the liquid crystal display device of the present invention, and FIG. 4 is a cross-sectional view taken along line I-I 'of FIG. Hereinafter, one subpixel will be described for the transverse electric field type liquid crystal display device.

3, a gate line 103 extending in one direction is disposed on a substrate (not shown), a data line 107 intersecting the gate line 103 and defining a subpixel P, . Then, a common line 109 which is in line with the gate line 103 intersects with the data line 107 is located. The subpixel P is defined by the intersection of the gate line 103, the data line 107 and the common line 109.

A source electrode 117 electrically connected to the gate electrode 104 extending from the gate line 103, a gate insulating film (not shown), a semiconductor layer (not shown), and the data line 107 is formed in the subpixel P, And a thin film transistor (TFT) composed of a source electrode 117 and a drain electrode 119 spaced apart.

In this figure, the channel region of the thin film transistor (TFT) is formed in an 'I' shape, but the present invention is not limited thereto. The thin film transistor TFT is shown protruding from the gate line 103 to the subpixel P but is not limited thereto and the gate electrode 103 may be formed as the gate line 103 itself.

The common electrode 123 branched inside the subpixel P is connected to the common line 109 through the contact hole CH1. In addition, the pixel electrode 135 alternating with the common electrode 123 is located corresponding to the branched common electrode 123. Here, the pixel electrode 135 is connected to the drain electrode 119 of the thin film transistor TFT.

Hereinafter, the cross-sectional structure according to the plane structure of the above-described transverse electric field type liquid crystal display device of the present invention will be described.

Referring to FIG. 4, in the transverse electric field type liquid crystal display device of the present invention, a gate electrode 104 extending from a gate line (not shown) arranged in one direction on a TFT array substrate 101 is located. A gate insulating film 106 is formed on the gate electrode 104 to insulate them and a semiconductor layer 115 is formed on the gate insulating film 106 in a region corresponding to the gate electrode 103. The source electrode 117 and the drain electrode 119 are located at both side ends of the semiconductor layer 115 and include the gate electrode 103, the semiconductor layer 115, the source electrode 117 and the drain electrode 119 (TFT) which constitutes a thin film transistor.

The pixel electrode 135 is located on the gate insulating film 106. A passivation film 125 covering the source electrode 117, the drain electrode 119 and the pixel electrode 135 is positioned to constitute the TFT array substrate 101. [ The common electrode 123 is positioned on the passivation film 125 to correspond to the pixel electrode 135. The pixel electrode 135 and the common electrode 123 are alternately positioned.

The color filter substrate 140 facing the TFT array substrate 101 is positioned. The color filter substrate 140 has R, G and B color filters 144 on the lower surface thereof and a black matrix 142 between the color filters 144. An overcoat layer 145 is disposed on the color filter 144 and a rear ITO 160 for preventing static electricity is disposed on the color filter substrate 140 to constitute a color filter substrate 140. A liquid crystal layer 150 is interposed between the TFT array substrate 101 and the color filter substrate 140 to constitute a transverse electric field type liquid crystal display device of the present invention.

Hereinafter, the Ag dot and the auxiliary line of the liquid crystal display according to the embodiment of the present invention will be described as follows.

FIG. 5 is a plan view of a liquid crystal display device according to an embodiment of the present invention, and FIG. 6 is a cross-sectional view taken along line II-II 'of FIG. 7 to 9 are plan views illustrating a liquid crystal display device according to another embodiment of the present invention.

5, a liquid crystal display 100 according to an embodiment of the present invention includes a TFT array substrate 101, a color filter substrate 140, and a liquid crystal layer (not shown) interposed therebetween . The thin film transistor, the pixel electrode connected to the thin film transistor, the common electrode and the like are formed on the TFT array substrate 101, and the color filter substrate 140 is formed of a black matrix, a color filter, etc., It will be omitted.

On one side of the TFT array substrate 101, a driving IC 155 to which a signal is applied to the thin film transistor of the TFT array substrate 101 is formed. A ground pad 185 is formed on one side of the TFT array substrate 155 to make contact with the Ag dot 180. A rear ITO 160 is formed on the front surface of the color filter substrate 140 to discharge static electricity generated in the color filter substrate 140. An auxiliary line 165 is formed on the top edge of the back ITO 160 and is located in a shape surrounding the back ITO 160. A detailed description of the auxiliary line 165 will be described later.

Ag dots 180 are applied over the TFT array substrate 101 and the color filter substrate 140 to electrically ground the auxiliary line 165, the back surface ITO 160, and the ground pad 185.

6, a back-side ITO 160 is positioned on the color filter substrate 140 and an auxiliary line 165 is positioned on the back-side ITO 160. As shown in FIG. An Ag dot 180 for electrically connecting the back surface ITO 160 to the auxiliary line 165 and the ground pad 185 is located. An upper polarizer 170b is attached to the back ITO 160 and the Ag dot 180 and a lower polarizer 170a is attached to the lower surface of the TFT array substrate 101. [

Particularly, in the present invention, the auxiliary line 165 is further formed on the rear ITO 160. The auxiliary line 165 is formed on the upper edge of the rear ITO 160 so that the rear ITO 160 is short- So that it electrically conducts. The auxiliary line 165 is formed in the same process as the Ag dot 180. As the method of forming the auxiliary line 165, an Ag paste including Ag particles, glass frit and a solvent is prepared and applied to the liquid crystal panel LP by a method such as dispensing or spraying to form an auxiliary line 165 ).

The auxiliary line 165 of the present invention may be formed in various structures. As shown in FIG. 5, an auxiliary line 165 is formed to surround all four edges of the rear ITO 160. As described above, the auxiliary line 165 serves to electrically connect the back-side ITO 160 through the auxiliary line 165 even if the back-side ITO 160 is short-circuited.

7, an auxiliary line 165 may be formed continuously on at least two edges of the backside ITO 160 to be connected to the Ag dot 180. As shown in FIG. 8, the auxiliary line 165 may be continuously formed on the three edges of the rear ITO 160 while being connected to the Ag dot 180. 9, the auxiliary line 165 may be formed only at one edge of the back ITO 160 that can be connected to the Ag dot 180 at a minimum.

The auxiliary line 165 of the present invention may be located anywhere if it is formed only on at least one edge of the back ITO 160 connected to the Ag dot 180 at least. An auxiliary line 165 is also formed outside the active area A / A where the image is implemented. The auxiliary line 165 is made of conductive particles of Ag, and the transmittance of the image is lowered when the auxiliary line 165 is formed on the active area A / A. Thus, the auxiliary line 165 is formed outside the active area A / A.

In addition, since the auxiliary line 165 has conductivity, when the auxiliary line 165 is formed on the rear ITO 160, the resistance of the rear ITO 160 can be remarkably reduced. Thereby, the thickness of the rear ITO 160 can be reduced and the transmittance can be improved.

6, after the auxiliary line 165 is formed, the Ag dot 180 is formed to extend over the back ITO 160, the auxiliary line 165, and the ground pad 185. As shown in FIG. Therefore, the back-side ITO 160 and the auxiliary line 165 are grounded to the ground pad 185 by the Ag dot 180, so that the static electricity generated in the future can be discharged.

Hereinafter, the display device having the rear ITO and auxiliary lines of the present invention will be described in detail in the following Comparative Examples and Examples. However, the following examples are illustrative of the present invention, but the present invention is not limited to the following examples.

Comparative Example 1

A display device was manufactured by attaching an upper polarizer on a liquid crystal panel without forming rear ITO.

Comparative Example 2

A display device was fabricated in the same manner as in Comparative Example 1 except that rear ITO was formed at a thickness of 110 ANGSTROM, 210 ANGSTROM, and 310 ANGSTROM, respectively.

Example

A display device was manufactured under the same process conditions as in Comparative Example 2, except that auxiliary lines were formed on the back ITO.

The display device manufactured in accordance with the above-described Comparative Examples 1 and 2 and Example was operated for 240 hours at a temperature of 60 ° C and a humidity of 90% to perform a high temperature and high humidity reliability test. Then, the protective film of the upper polarizer was peeled off, The transmittance of the display device was measured, and the resistance between the ends of the panel was measured. The results are shown in Table 1 below. (In this case, in the case of the embodiment, all of the auxiliary lines are conducted, and the resistance between the ends of the panel can not be measured.)

Comparative Example 1 Comparative Example 2 Example Thickness (Å) of backside ITO 0 110 210 310 110 210 310 Transmittance (%) 100 99 97.5 94 99 97.5 94 Whitening ○ ○ × × × × × Resistance (KΩ) - 34.3 12 11 - - -

Referring to Table 1, in Comparative Examples 1 and 2 in which auxiliary lines were not formed after the high-temperature high-humidity reliability test, whitening occurred due to short-circuiting of the rear ITO. At this time, in Comparative Example 2, whitening was not observed when the rear ITO was formed to a thickness of 210 and 310 ANGSTROM, but it was confirmed that the transmittance was lowered.

On the other hand, in the embodiment in which the auxiliary line is formed, it is confirmed that whitening phenomenon occurs due to short-circuiting of the rear ITO. Also, it was confirmed that although the transmittance was the same as that of Comparative Example 2, the transmittance could be further increased because the thickness of the back ITO was reduced due to the auxiliary line.

As described above, the display device according to the embodiment of the present invention has an advantage that the auxiliary line is formed on the rear ITO so that even if the rear ITO is short-circuited, the display can exhibit the same level of characteristics as no short circuit has occurred . Therefore, the reliability of the display device can be improved. In addition, there is an advantage that the thickness of the rear ITO can be reduced to improve the transmittance.

Meanwhile, the structure of the transverse electric field type liquid crystal display device described in the present invention is merely one example, and the present invention is not limited thereto, but may be applied to all display devices having a rear ITO.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood that the invention may be practiced. It is therefore to be understood that the embodiments described above are to be considered in all respects only as illustrative and not restrictive. In addition, the scope of the present invention is indicated by the following claims rather than the detailed description. Also, all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included within the scope of the present invention.

101: TFT array substrate 140: color filter substrate
155: driving IC 160: backside ITO
165: auxiliary line 180: Ag dot
185: Ground pad A / A: Active area

Claims (5)

A liquid crystal panel having a liquid crystal layer interposed between the color filter substrate and the TFT array substrate;
A ground pad formed on the TFT array substrate;
A polarizing plate formed on the color filter substrate;
A rear ITO formed on the front surface of the polarizer;
An auxiliary line formed on at least one edge of the back ITO on the back ITO; And
And Ag dots in contact with the auxiliary line, the back ITO, and the ground pad.
The method according to claim 1,
Wherein the auxiliary line is made of the same material as the Ag dot.
The method according to claim 1,
Wherein the auxiliary line is located at least at one edge of the back ITO connected to the Ag dot.
The method of claim 3,
Wherein the auxiliary line is located at all edges of the back ITO.
The method according to claim 1,
Wherein the auxiliary line is located outside an active area in which an image is displayed.

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