Touch panel display apparatus and method of fabricating the same

A touch panel display apparatus includes an upper sheet having an upper transparent film formed of one of a crystalline transparent conductive material and an amorphous transparent conductive material, and a lower sheet having a lower transparent film formed of one of an other one of the crystalline transparent conductive material and the amorphous transparent conductive material.

The present invention claims the benefit of Korean Patent Application No. P2001-86557 filed in Korea on Dec. 28, 2001, which is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a display apparatus, and more particularly to a touch panel display apparatus and a fabricating method thereof.

2. Description of the Related Art

In typical applications for touch panel display apparatus, voltage or current signals are generated corresponding to a position that is pressed on the panel with a stylus pen or a finger, the signals thereby inputting an order or graphic information designated by a user. A resistive touch panel with an analog input method is commonly used, and is integrated with a liquid crystal display panel, such as a flat panel display. The liquid crystal display panel generally controls a light transmittance of liquid crystal cells interposed between two glass substrates to display an image. Each of the liquid crystal cells response to a video signal, i.e., a corresponding pixel signal to control the volume of transmitted light.

FIG. 1a perspective view of a touch panel apparatus mounted on a liquid crystal display panel according to the related art. InFIG. 1, a touch panel32is mounted on a liquid crystal panel31and a backlight33. The touch panel32is electrically connected to a computer system35via a touch controller34and signal lines36. Accordingly, during operation of the touch panel32, a voltage value of a contacted position is calculated at the touch controller34to recognize coordinates of the contacted position.

FIG. 2is a cross sectional view of the touch panel apparatus ofFIG. 1according to the related art. InFIG. 2, the liquid crystal display panel31includes an upper plate31aand a lower plate31b, and the touch panel32includes an upper plate32aand a lower plate32b, and a polarizer4is formed between the liquid crystal display panel31and the touch panel32.

The liquid crystal panel31includes liquid crystal material14and spacers5interposed between the lower plate31band the upper plate31a. A gate line6, an insulation film8, a pixel electrode10a, and a first alignment film12aare sequentially formed on a lower substrate of the lower plate31b. The upper plate31aincludes a black matrix16, a color filter18, a common electrode10b, and a second alignment film12bsequentially formed on the bottom surface thereof. The spacer5is formed on the first alignment film12abefore the upper plate31ais bonded with the lower plate31b. The spacer5separates the upper plate31afrom the lower plate31bby a uniform gap, thereby creating a uniform thickness of the liquid crystal material14.

The touch panel32includes a spacer28formed between the lower plate32band the upper plate32a, and may include a polyethylene terephthalate (PET) film. On a lower sheet20of the lower plate32bis formed a lower transparent film26, and on an upper sheet24of the upper plate32ais formed an upper transparent film27. The upper sheet24is formed of PET and the lower sheet20is formed of one among glass, plastic and PET. The upper and lower transparent films27and26are formed of transparent conductive material with good transmittance. For example, one of indium-tin-oxide ITO, indium-zinc-oxide IZO and indium-tin-zinc-oxide ITZO.

An upper electrode layer is formed at the end of the upper transparent film27, and a lower electrode layer is formed at the end of the lower transparent film26. The upper electrode layer is short-circuited from the lower electrode layer when the upper sheet24is pressed by a stylus pen or a finger, thereby generating a current or voltage level signal that varies in accordance with the pressed position. In addition, the upper and the lower electrode layer is formed of a metal material with good conductivity, such as silver Ag. The upper and the lower transparent films27and26are both formed with an amorphous ITO structure or a crystalline ITO structure.

The polarizer4is formed between the lower plate32bof the touch panel32and the upper plate31aof the liquid crystal display panel31, and converts visible light into linear polarized light at the both sides of the liquid crystal display panel31. A first adhesive1ais formed between the polarizer4and the lower plate32bof the touch panel32, and a second adhesive1bis formed between the polarizer4and the upper plate31a.

FIG. 3is a plane view of an electrode and signal line formed on the touch panel ofFIG. 2according to the related art, andFIG. 4is a perspective view of upper and lower plates of the touch panel ofFIG. 3according to the related art.

InFIGS. 3 and 4, the upper plate32a(inFIG. 4) of the touch panel32includes X-axis electrodes27aand27bformed at the edge thereof along a vertical direction, and signal lines28cand28dderived from the center of the X-axis electrode27aand27bfor supplying the signal with the current or the voltage level to the touch controller34. The lower plate32b(inFIG. 4) of the touch panel32includes Y-axis electrodes26aand26bformed at the edge thereof along a horizontal direction, and signal lines28aand28bderived from the center of the Y-axis electrodes26aand26bfor supplying the signal with the current or the voltage level to the touch controller34. The signal lines28a,28b,28c, and28dinclude a tail part and an electrode extension connected to the electrodes26a,26b,27a, and27b. Accordingly, the signal lines28a,28b,28c, and28dderived from the center of the electrodes26a,26b,27a, and27bextend to one side of the touch panel32for make connection to a touch panel controller (not shown).

When the upper and the lower transparent films27and26of the touch panel32are formed of amorphous ITO, the upper and the lower transparent film27and26have low durability and low wear-resistance. Accordingly, if the touch panel apparatus32is used for a long period of time, the upper and lower sheets24and20begin to separate from the upper and the lower films27and26. Thus, the linearity of the voltage detected from the upper and the lower electrode layers is disrupted. On the other hand, when the upper and the lower transparent films27and26are formed with the crystalline ITO structure, the transparent films have a flexible property. Such crystalline structure can be formed by depositing ITO material and treating with heat at a high temperature below the melting point. The ITO material has an amorphous structure when depositing the ITO material, and the heat treatment changes it to a crystalline structure. In addition, since the upper and the lower transparent films27and26of the crystalline ITO structure are flexible, they are not durable. Accordingly, the ITO film easily deteriorates when the touch panel is used for a long period of time, thereby disrupting the linearity of the voltage detected at the upper and the lower electrode layers.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to a touch panel apparatus and a fabricating method thereof that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.

An object of the present invention to provide a touch panel apparatus and a fabricating method thereof that improves durability by using both crystalline and amorphous transparent films.

To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, a touch panel display apparatus includes an upper sheet having an upper transparent film formed of one of a crystalline transparent conductive material and an amorphous transparent conductive material, and a lower sheet having a lower transparent film formed of one of an other one of the crystalline transparent conductive material and the amorphous transparent conductive material.

In another aspect, a method of fabricating a touch panel display apparatus includes forming an upper sheet and a lower sheet, forming a first transparent conductive material having one of a crystalline structure and amorphous structure on the upper sheet to form an upper transparent film, and forming a second transparent conductive material having an other one of the crystalline structure and the amorphous structure on the lower sheet to form a lower transparent film.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 5is a cross sectional view of an exemplary touch panel apparatus mounted on a liquid crystal display panel according to the present invention. InFIG. 5, the touch panel apparatus may include a liquid crystal display panel131having an upper plate131aand a lower plate131b, a touch panel132having an upper plate132aand a lower plate132b, and a polarizer14formed between the liquid crystal display panel131and the touch panel132. The liquid crystal panel131may include liquid crystal material114interposed between the lower plate131band the upper plate131a, and a spacer15. A gate line16, an insulation film18, a pixel electrode110a, and a first alignment film112amay be sequentially formed on a lower substrate of the lower plate131b. The upper plate131amay include a black matrix116, a color filter118, a common electrode110b, and a second alignment film112bsequentially formed on a bottom surface thereof. The spacer15may be formed on the first alignment film112abefore the upper plate131ais bonded with the lower plate131b. The spacer15may separate the upper plate131afrom the lower plate131bwith a uniform gap maintained to make a thickness of the liquid crystal material114uniform.

The touch panel132may include a spacer128formed between the lower plate132band the upper plate132a, and the spacer128may include a PET film. On a lower sheet120of the lower plate132bmay be formed a lower transparent film142, and on an upper sheet124of the upper plate132amay be formed an upper transparent film140. The upper sheet124may include PET, and the lower sheet120may include one of glass, plastic, and PET.

An upper electrode layer may be formed at an end of the upper transparent film140, and a lower electrode layer may be formed at an end of the lower transparent film142. The upper electrode layer may be short-circuited from the lower electrode layer when the upper sheet124is pressed by a stylus pen or a finger, to generate a signal having the current or voltage level variable in accordance with the pressed position. Accordingly, the upper and the lower electrode layer may be formed of a metal material with good conductivity, for example, by printing silver Ag on it.

The upper and lower transparent films140and142may be formed of one of ITO, IZO, and ITZO. The upper and the lower transparent films140and142may be deposited to a thickness of about 300 Å. The upper and the lower transparent film140and142may be formed of ITO materials having different crystalline structures from each other. For example, if the upper transparent film140is formed of crystalline ITO material, then the lower transparent film142is formed of amorphous ITO material. Alternatively, if the upper transparent film140is formed of amorphous ITO material, then the lower transparent film142is formed of crystalline ITO material.

The upper and the lower transparent films140and142may be formed by depositing ITO materials to form amorphous ITO material. Accordingly, the deposition process may be followed by a heat treatment process with a high temperature. For example, after depositing the amorphous ITO material, the amorphous ITO material may be treated with heat at a high temperature below the melting point of the ITO material, whereby the amorphous ITO material may be changed to crystalline ITO material. By forming the upper transparent film140and the lower transparent film142of different crystal structured ITO materials, durability and wear-resistance may be increased and brittleness be overcome.

FIG. 6is a plan view of an exemplary electrode and signal line formed on the touch panel ofFIG. 5according to the present invention, andFIG. 7is a perspective view of exemplary upper and lower plates of the touch panel ofFIG. 6according to the present invention. InFIG. 6, the upper plate132a(inFIG. 5) of the touch panel132may include X-axis electrodes142aand142bformed along an edge thereof along a vertical direction, and signal lines128cand128dmay be derived from a center of the X-axis electrode142aand142bfor supplying the current or the voltage level signals to a touch controller (not shown).

InFIG. 7, the lower plate132bof the touch panel132may include Y-axis electrodes142aand142bformed along an edge thereof along a horizontal direction, and signal lines128aand128bmay be derived from a center of the Y-axis electrodes142aand142bfor supplying the current or voltage level signals to the touch controller (not shown). The signal lines128a,128b,128c, and128dmay include a tail part and an electrode extension connected to the electrodes142a,142b,140a, and140b. Accordingly, the signal lines128a,128b,128c, and128may be derived from a center of the electrodes142a,142b,140a, and140bextended to one side of the touch panel132to make the connection to the touch controller (not shown).

The touch panel apparatus according to the present invention may be applicable to Plasma Display Panels (PDP), Field Emission Displays (FED), and Electro Luminescence Devices (ELD) in addition to a liquid crystal display panel formed at a bottom of a touch panel.