KR101950821B1 - Liquide crystal display device with embedded touch panel therein and method for fabricating the same - Google Patents

Abstract

A touch panel built-in liquid crystal display device capable of preventing a contact failure between a bridge electrode and a common electrode by forming a plurality of trenches in a planarization film so that an alignment film is not left in a region where a bridge electrode and a common electrode are electrically connected, A touch panel built-in liquid crystal display device of the present invention includes a planarization layer formed on a first substrate and having a plurality of trenches, and a planarization layer formed on the planarization layer and formed along the plurality of trenches A thin film transistor array substrate comprising: a first common electrode; a second common electrode formed separately by sandwiching the first common electrode; and a lower alignment layer which is introduced into the plurality of trenches and exposes the second common electrode, , A second substrate formed on a second substrate facing the first substrate and exposed by the lower alignment layer A column spacer formed in a region corresponding to the first common electrode, and a bridge electrode formed on the second substrate on which the column spacer is formed and connected to the second common electrode.

Description

TECHNICAL FIELD [0001] The present invention relates to a touch panel built-in liquid crystal display device and a method of manufacturing the same,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a touch panel built-in liquid crystal display device, and more particularly, to a touch panel built-in liquid crystal display device and a method of manufacturing the same.

In recent years, as the information age has come to a full-fledged information age, a display field for visually expressing electrical information signals has been rapidly developed. In response to this, various flat panel display devices having excellent performance of thinning, light weight, Flat Display Device) has been developed to replace CRT (Cathode Ray Tube).

Specific examples of such flat panel display devices include a liquid crystal display device (LCD), a plasma display panel (PDP), a field emission display (FED) (Electro Luminescence Display Device: ELD). In general, a flat panel display panel that realizes an image is an essential component. The flat panel display panel has a pair of light emitting or polarizing material layers interposed therebetween The transparent insulating substrate is formed by laminating together.

In particular, a liquid crystal display device displays an image by adjusting the light transmittance of a liquid crystal using an electric field. To this end, the liquid crystal display device comprises a display panel having a liquid crystal cell, a backlight unit for irradiating the display panel with light, and a driving circuit for driving the liquid crystal cell. The display panel has a plurality of unit pixel regions defined by a plurality of gate lines and a plurality of data lines intersected with each other, a thin film transistor array substrate and a color filter array substrate opposing each other in each pixel region, And a liquid crystal filled in the cell gap.

The thin film transistor array substrate includes gate lines and data lines, thin film transistors formed by switching elements at intersections of the gate lines and data lines, pixel electrodes formed in units of liquid crystal cells and connected to the thin film transistors, And a lower alignment layer coated on the electrode. The gate lines and the data lines are supplied with signals from the driving circuits through respective pad portions, and the thin film transistors supply the pixel voltage signals to the pixel electrodes in response to the scan signals supplied to the gate lines.

The color filter array substrate includes a color filter formed on a unit of a liquid crystal cell, a color filter, a black matrix for reflecting external light, a common electrode commonly supplying a reference voltage to the liquid crystal cell, And an orientation film. Then, the thin film transistor substrate and the color filter array substrate separately manufactured in this way are aligned and then bonded to each other, and then the liquid crystal is injected and sealed.

In recent years, there has been a growing demand for a touch panel capable of recognizing a touch area and transmitting additional information in response to the touch of a user through a hand or a separate input device. At this time, the touch panel may be mounted on the liquid crystal display device, or may be built in the liquid crystal display device. Hereinafter, a general touch panel built-in liquid crystal display device will be described as follows.

1A is a plan view showing an arrangement of first and second common electrodes of a general touch panel built-in liquid crystal display device, and FIG. 1B is a cross-sectional view taken along line I-I 'of FIG. 1A. 2 is an enlarged cross-sectional view of the region A of FIG. 1B.

1A, first and second common electrodes 150a and 150b are formed on a thin film transistor array substrate 100a of a general touch panel built-in liquid crystal display device, and the first common electrode 150a has a long bar shape And the second common electrode 150b is separately formed between the first common electrodes 150a. 1B, the separated second common electrodes 150b are connected to each other through a bridge electrode 180 formed on the color filter array substrate 100b. Specifically, the bridge electrode 180 is connected to the thin film transistor array 100b, And is electrically connected to the second common electrode 150b through a column spacer 170 for maintaining a cell gap between the substrate 100a and the color filter array substrate 100b.

For example, when a voltage is sequentially applied to the first common electrode 150a, a change in capacitance occurring between the first common electrode 150a and the second common electrode 150b occurs depending on the touch state Detects the touch position by recognizing the change in capacitance, and outputs the detected touch position to the outside.

In particular, an alignment film is coated on the thin film transistor array substrate 100a and the color filter array substrate 100b for liquid crystal alignment. 2, an upper alignment film (not shown) applied on the color filter array substrate 100b is applied very thinly on the top of the column spacer 170 and flows down along the side surface of the column spacer 170 Is applied on a portion of the side of the column spacer 170 and on the bridge electrode 180 that does not correspond to the column spacer 170.

However, the lower orientation film 120 applied on the flat thin film transistor array substrate 100a is thickly applied, causing contact failure between the bridge electrode 180 and the second common electrode 150b, And the second common electrode 150b increases, so that it is not possible to realize a low resistance electrode.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and it is an object of the present invention to provide a method of forming a trench in a planarization film so as to prevent an alignment film from remaining in a region where a bridge electrode and a common electrode are electrically connected, A liquid crystal display device with a built-in touch panel.

According to an aspect of the present invention, there is provided a touch panel built-in liquid crystal display device including: a planarization layer formed on a first substrate and having a plurality of trenches; a plurality of trenches formed on the planarization layer, A thin film transistor array substrate comprising: a first common electrode; a second common electrode formed separately by sandwiching the first common electrode; and a lower alignment layer which is introduced into the plurality of trenches and exposes the second common electrode, A column spacer formed on a second substrate opposite to the first substrate and formed in a region corresponding to the first common electrode exposed by the lower alignment layer, and a second spacer formed on the second substrate on which the column spacer is formed And a bridge electrode connected to the second common electrode.

The planarization layer includes a drain contact hole exposing a drain electrode of a thin film transistor formed on the first substrate, and the plurality of trenches.

The thin film transistor array substrate further includes a pixel electrode connected to the thin film transistor through the drain contact hole.

The column spacer is located between the plurality of trenches.

According to another aspect of the present invention, there is provided a method of manufacturing a touch panel built-in liquid crystal display device including: forming a thin film transistor on a first substrate; Forming a planarization layer having a plurality of trenches and a drain contact hole exposing the thin film transistor on the first substrate including the thin film transistor; Forming a first common electrode formed on the planarization layer along the plurality of trenches and a second common electrode separately formed with the first common electrode interposed therebetween; Applying a lower alignment layer which is introduced into the plurality of trenches on the first substrate including the first and second common electrodes to expose the second common electrode; Forming a column spacer on the second substrate in a region corresponding to the first common electrode exposed by the lower alignment layer; Forming a bridge electrode connected to the second common electrode on the second substrate on which the column spacer is formed; And opposing the first and second substrates.

A drain contact hole and a plurality of trenches of the planarization layer are formed using a halftone mask.

The thin film transistor array substrate further includes forming a pixel electrode connected to the thin film transistor through the drain contact hole.

The column spacer is formed between the plurality of trenches.

The above-described touch panel built-in liquid crystal display device and its manufacturing method of the present invention have the following effects.

First, a plurality of trenches are formed in the planarization layer, and a lower alignment film is introduced into the planarization layer by a plurality of trenches, so that the contact characteristics between the bridge electrode and the common electrode can be improved.

Second, a plurality of trenches formed in the planarization layer and drain contact holes for exposing the thin film transistor are formed by using a halftone mask, and a plurality of trenches can be formed without further increasing the mask process, thereby improving contact characteristics .

1A is a plan view showing an arrangement of first and second common electrodes in a general touch panel built-in liquid crystal display device.
1B is a cross-sectional view taken along line I-I 'of FIG. 1A;
FIG. 2 is an enlarged cross-sectional view of region A of FIG. 1B. FIG.
3 is a sectional view of a touch panel built-in liquid crystal display device of the present invention.
4 is a SEM of a trench of a liquid crystal display device incorporating a touch panel of the present invention.
5A to 5E are process sectional views of a liquid crystal display device incorporating a touch panel of the present invention.
6A is a SEM in which an alignment film remains on a column spacer of a general touch panel built-in liquid crystal display device.
6B is a SEM in which no alignment film remains on a column spacer of a liquid crystal display device with a built-in touch panel of the present invention.

Hereinafter, a touch panel built-in liquid crystal display device of the present invention will be described in detail with reference to the accompanying drawings.

3 is a cross-sectional view of a touch panel built-in liquid crystal display device of the present invention. 4 is an SEM of a trench of a touch panel built-in liquid crystal display device of the present invention.

As shown in FIG. 3, the liquid crystal display device with built-in touch panel of the present invention includes a thin film transistor array substrate and a color filter array substrate which are adhered to each other with a liquid crystal layer (not shown) interposed therebetween.

Though not shown, a thin film transistor (TFT) is formed on the first substrate 210 of the thin film transistor array substrate. Specifically, a plurality of gate lines and data lines intersect the first substrate 210 to define a plurality of pixel regions, and a thin film transistor is formed in an intersection region between the gate lines and the data lines.

The thin film transistor includes a gate electrode, a gate insulating film, a semiconductor layer, and source and drain electrodes, and a planarization layer 220 is formed on the entire surface of the first substrate 210 including the thin film transistor. A pixel electrode 230 is formed on the planarization layer 220 and the pixel electrode 230 is connected to the drain electrode of the TFT through a drain contact hole (not shown) formed by selectively removing the planarization layer 220.

A protective film 240 is formed on the planarization layer 220 including the pixel electrode 230 and a first common electrode (not shown) having a long bar shape and a first common electrode The second common electrode 250 is formed in a separated structure, and only the second common electrode 250 is shown in the drawing. The first and second common electrodes 250 and 250 are formed of a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO) to detect a touch.

More specifically, if one of the first and second common electrodes (not shown) is a driving electrode to which a voltage is applied, the other is a sensing electrode that detects a voltage signal. When a voltage value is detected on the sensing electrode side by touching the liquid crystal display device, the capacitance of the intersection of the first and second common electrodes (not shown) So that the touch area can be detected.

A black matrix 270 is formed on the second substrate 260 of the color filter array substrate which is adhered to the thin film transistor array substrate and a color filter 280 is formed to overlap with the black matrix 270. An overcoat layer 290 is formed on the entire surface of the second substrate 260 including the black matrix 270 and the color filter 280 to planarize the surface of the second substrate 260.

On the overcoat layer 290 corresponding to the black matrix 270, a column spacer 300 for maintaining the cell gap of the thin film transistor array substrate and the color filter array substrate is formed. A bridge electrode 310 is formed on the overcoat layer 290 including the column spacer 300 to electrically connect the second common electrode 250 formed separately from the thin film transistor array substrate.

In particular, the upper and lower alignment films 400a and 400b are applied on the thin film transistor array substrate and the color filter array substrate, respectively, for liquid crystal alignment. The upper alignment film 400a applied on the color filter array substrate is very thinly applied to the top of the column spacer 300 and flows down along the side surface of the column spacer 300 so that the side surface of the column spacer 300, Is applied on the bridge electrode (310) not corresponding to the spacer (300).

However, the lower orientation film 400b applied on the flat thin film transistor array substrate is thickly applied, resulting in poor contact between the bridge electrode 310 and the second common electrode 250, The resistance between the second common electrodes 250 becomes large.

Accordingly, in order to prevent such contact defects as described above, the present invention forms a plurality of trenches 220a in the planarization layer 220 of the thin film transistor array substrate, as shown in FIG. The trench 220a is formed around the column spacer 300 to which the bridge electrode 310 and the second common electrode 250 are connected and is formed on the surface of the first and second common electrodes (not shown) The lower alignment layer 400b of the region where the first common electrode 310 and the second common electrode 250 are connected to the plurality of trenches 220a.

Specifically, the pixel electrode 230, the protective layer 240, and the first and second common electrodes (not shown) (not shown) formed on the planarization layer 220 are formed to have a drain contact hole (not shown) and a trench 220a A lower alignment layer 400b is formed on the entire surface of the first substrate 210 including the first and second common electrodes 250. The lower alignment layer 400b includes a plurality of trenches 220a formed around the column spacer 300, Respectively.

The bridge electrode 310 on the column spacer 300 is connected to the exposed second common electrode 250 due to the lower alignment layer 400b flowing into the trench 220a, The device can reduce the contact failure between the bridge electrode 310 and the second common electrode 250 and form a low resistance electrode.

In particular, since the pixel electrode 230 formed on the planarization layer 220 is electrically connected to the drain electrode through the drain contact hole exposing the drain electrode of the TFT by selectively removing the planarization layer 220, It is preferable that the trench 220a does not expose the wiring under the planarization layer 220 so that the pixel electrode 230 is not connected to another metal wiring except the drain electrode through the through holes 220a.

Hereinafter, a manufacturing method of a touch panel built-in liquid crystal display device of the present invention will be described in detail with reference to the accompanying drawings.

FIGS. 5A to 5E are process sectional views of a liquid crystal display device incorporating a touch panel of the present invention, FIGS. 5A to 5C are process sectional views of a thin film transistor array substrate of a liquid crystal display device with a touch panel of the present invention, Sectional view of the color filter array substrate of the touch panel built-in liquid crystal display device of the present invention. 5F is a cross-sectional view of the thin film transistor array substrate and the color filter array substrate of the touch panel built-in liquid crystal display device of the present invention assembled together.

5A, a planarization layer 220 is formed on a first substrate 210 on which a thin film transistor including a gate electrode, a gate insulating layer, a semiconductor layer, and a source and a drain electrode is formed. The planarization layer 220 may be formed of an inorganic material such as a silicon nitride film (SiNx), a silicon oxide film (SiOx), or an organic material such as BCB.

Then, the planarization layer 220 is selectively removed to form a drain contact hole (not shown) for exposing the drain electrode of the thin film transistor, and a plurality of trenches 220a are formed. Specifically, a photoresist is applied on the planarization layer 220, a drain contact hole (not shown) is formed by using a halftone mask having a transmission region, a semi-transmission region, and a blocking region, Thereby forming a plurality of trenches 220a.

The pixel electrode 230 is electrically connected to the drain electrode through the drain contact hole exposing the drain electrode of the TFT by selectively removing the planarization layer 220. The pixel electrode 230 is electrically connected to the drain electrode through the trench 220a, It is preferable that the trench 220a does not expose the wiring under the planarization layer 220 so as not to connect to the other metal wiring except the drain electrode. The depth of the trench 220a can be adjusted by adjusting the transmittance of the transflective region of the halftone mask.

5B, a pixel electrode 230 is formed on the entire surface of the planarization layer 220 including a drain contact hole (not shown) and a plurality of trenches 220a. The pixel electrode 230 includes a drain contact hole (not shown) To the drain electrode of the thin film transistor. A protective film 240 is formed on the pixel electrode 230.

Next, a first common electrode (not shown) and a second common electrode 250 are formed on the protective layer 240 to sense a touch, and only the second common electrode 250 is shown in the drawing. Specifically, the first common electrode (not shown) is formed in a long bar shape, and the second common electrode 250 is formed between the first common electrodes (not shown) and formed in a separated structure.

For example, if one of the first and second common electrodes (not shown) is a driving electrode to which a voltage is applied, the other is a sensing electrode that detects a voltage signal. A voltage signal is sequentially applied to the driving electrode and a voltage value is detected on the sensing electrode side. When a user touches the liquid crystal display device, capacitance of the intersection of the first and second common electrodes (not shown) ) Is changed to detect the touch position and output the detected touch position to the outside.

Next, in order to align the liquid crystal molecules, the lower alignment film 400b is coated on the first and second common electrodes (not shown) as shown in FIG. 5C. At this time, the lower alignment layer 400b flows into the plurality of trenches 220a, and the second common electrode 250 is exposed due to the lower alignment layer 400b flowing into the trenches 220a.

5D, a black matrix 270 is formed on the second substrate 260, and a color filter 280 is formed so as to overlap with the black matrix 270. As shown in FIG. An overcoat layer 290 is formed on the entire surface of the second substrate 260 including the black matrix 270 and the color filter 280 to flatten the surface of the second substrate 260 and to cover the overcoat layer 290 And the step of forming may be omitted.

5E, a column spacer 300 is formed on the overcoat layer 290 corresponding to the black matrix 270 to maintain a cell gap between the thin film transistor array substrate 200a and the color filter array substrate 200b do. A bridge electrode 310 is formed on the overcoat layer 290 including the column spacer 300 to electrically connect the separated second common electrode 250.

Particularly, the upper alignment layer 400a is also applied on the second substrate 260 including the bridge electrode 310. The upper alignment layer 400a is applied very thinly on the upper portion of the column spacer 300, And is applied onto a portion of the side surface of the column spacer 300 and the bridge electrode 310 that does not correspond to the column spacer 300.

5F, since the bridge electrode 310 on the column spacer 300 is connected to the second common electrode 250 exposed by the lower alignment layer 400b flowing into the trench 220a, The touch panel built-in liquid crystal display device can reduce the contact failure between the bridge electrode 310 and the second common electrode 250, thereby forming a low-resistance electrode.

6A is an SEM in which an alignment film remains on a column spacer of a general touch panel built-in liquid crystal display device, and FIG. 6B is an SEM in which no alignment film remains on a column spacer of a touch panel built-in liquid crystal display device of the present invention.

6A, in a general touch panel built-in liquid crystal display device, a 38.1 nm thick alignment layer is directly applied to the planarization layer, and a contact defect between the bridge electrode and the second common electrode for connecting the separated second common electrodes may occur have. However, as shown in FIG. 6B, in the liquid crystal display device with a built-in touch panel of the present invention, the alignment film flows through the trench, and no alignment film remains on the column spacer. Therefore, the contact characteristics between the bridge electrode and the second common electrode can be improved to realize a low-resistance electrode, a trench can be formed to form the drain contact hole, and the bridge electrode and the second common electrode The contact characteristics of the electrode can be improved.

While the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. Will be apparent to those of ordinary skill in the art.

210: first substrate 220: planarization layer
220a: Trench 230: Pixel electrode
240: protective film 250: second common electrode
260: second substrate 270: black matrix
280: color filter 290: overcoat layer
300: column spacer 310: bridge electrode
400a: upper alignment film 400b: lower alignment film

Claims (8)

A planarization layer formed on the first substrate and having a plurality of trenches, a first common electrode formed on the planarization layer and formed along the plurality of trenches, and a second common electrode formed separately on the first common electrode A thin film transistor array substrate including a first common electrode, a second common electrode, and a lower alignment layer which is introduced into the plurality of trenches and exposes the second common electrode,
A column spacer formed on the second substrate facing the first substrate and formed between the plurality of trenches in a region corresponding to the first common electrode exposed by the lower alignment layer; And a bridge electrode formed on the second substrate and connected to the second common electrode. The touch panel built-in liquid crystal display device of claim 1, The method according to claim 1,
Wherein the planarization layer includes a drain contact hole exposing a drain electrode of a thin film transistor formed on the first substrate, and the plurality of trenches. 3. The method of claim 2,
Wherein the thin film transistor array substrate further comprises a pixel electrode connected to the thin film transistor through the drain contact hole. delete Forming a thin film transistor on the first substrate;
Forming a planarization layer having a plurality of trenches and a drain contact hole exposing the thin film transistor on the first substrate including the thin film transistor;
Forming a first common electrode formed on the planarization layer along the plurality of trenches and a second common electrode separately formed with the first common electrode interposed therebetween;
Applying a lower alignment layer which is introduced into the plurality of trenches on the first substrate including the first and second common electrodes to expose the second common electrode;
Forming a column spacer on the second substrate so as to be located between the plurality of trenches in a region corresponding to the first common electrode exposed by the lower alignment layer;
Forming a bridge electrode connected to the second common electrode on the second substrate on which the column spacer is formed; And
And attaching the first and second substrates to each other in a face-to-face manner. 6. The method of claim 5,
Wherein the drain contact hole of the planarization layer and the plurality of trenches are formed using a halftone mask. 6. The method of claim 5,
And forming a pixel electrode connected to the thin film transistor through the drain contact hole after forming the planarization layer. delete

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