KR100763407B1 - array panel for liquid crystal display devices - Google Patents

Abstract

The present invention relates to an array substrate for a liquid crystal display device incorporating a drive circuit.

In the COG type liquid crystal display device, by forming a LOG wiring connecting the gate and the data driving circuit on the array substrate, the manufacturing process can be simplified and the cost can be reduced. However, this LOG wiring replaces the FPC and requires very low resistance.

In the present invention, in the array substrate used in the reflective or semi-transmissive liquid crystal display device, by forming the LOG wiring at the time of forming the gate wiring and the pixel electrode, the wiring width can be formed wide to reduce the resistance of the wiring and the manufacturing process Not increased.

Chip on Glass (COG), Line on Glass (LOG), Low Resistance

Description

Array substrate for liquid crystal display device             

1 is a cross-sectional view of a general liquid crystal display device.

2 is a cross-sectional view of a general transflective liquid crystal display device.

3 is a plan view of an array substrate for a COG type liquid crystal display device.

4 is a plan view of an array substrate for a conventional LOG method liquid crystal display.

5 and 6 are plan and cross-sectional views, respectively, of part C of FIG. 4.

7 is a plan view of an array substrate according to the present invention.

8 and 9 are a plan view and a sectional view of portion D of FIG.

The present invention relates to a liquid crystal display device, and more particularly, to an array substrate for a liquid crystal display device incorporating a driving circuit.

Recently, with the rapid development of the information society, there is a need for a flat panel display having excellent characteristics such as thinning, light weight, and low power consumption, among which a liquid crystal display has a resolution, It is excellent in color display and image quality, and is actively applied to notebooks and desktop monitors.

In general, a liquid crystal display device arranges two substrates on which electrodes are formed so that the surfaces on which the two electrodes are formed face each other, injects a liquid crystal material between the two substrates, and applies a voltage to the two electrodes to generate an electric field. By moving the liquid crystal molecules, the image is expressed by the transmittance of light that varies accordingly.

Hereinafter, a structure of a general liquid crystal display device will be described with reference to the accompanying drawings.

1 is a cross-sectional view of a general liquid crystal display.

As shown in FIG. 1, the liquid crystal display includes a first area A in which an image is represented and a pad (not shown) in which a pad for applying a signal to the first area A is located. It is divided into two areas (B).

In the first region A, first, a gate electrode 11 made of a conductive material such as a metal is formed on the lower transparent first substrate 10, and a silicon nitride film (SiN _x ) or a silicon oxide film (SiO ₂ ) is formed thereon. The gate insulating film 12 made of) covers the gate electrode 11. An active layer 13 made of amorphous silicon is formed on the gate insulating layer 12 on the gate electrode 11, and an ohmic contact layer 14 made of amorphous silicon doped with impurities is formed thereon.

Source and drain electrodes 15a and 15b formed of a conductive material such as a metal are formed on the ohmic contact layer 14, and the source and drain electrodes 15a and 15b are formed together with the gate electrode 11. ).

Although not shown, the gate electrode 11 is connected to the gate wiring, the source electrode 15a is connected to the data wiring, and the gate wiring and the data wiring are orthogonal to each other to define the pixel region.

Subsequently, a passivation layer 16 made of a silicon nitride film, a silicon oxide film, or an organic insulating film is formed on the source and drain electrodes 15a and 15b, and the passivation layer 16 is a contact hole 16c exposing the drain electrode 15b. Has

A pixel electrode 17 made of a transparent conductive material is formed in the pixel area above the passivation layer 16, and the pixel electrode 17 is connected to the drain electrode 15b through the contact hole 16c.

Meanwhile, a transparent second substrate 20 spaced apart from the first substrate 10 at a predetermined interval is disposed on the first substrate 10, and a black matrix 21 is disposed on an inner surface of the second substrate 20. ) Is formed at a position corresponding to the thin film transistor T, although not shown, the black matrix 21 covers portions other than the pixel electrode 17. The color filter 22 is formed under the black matrix 21. The color filter 22 sequentially repeats red, green, and blue colors, and one color corresponds to one pixel area. The common electrode 23 made of a transparent conductive material is formed under the color filter 22.                         

Next, a liquid crystal 25 is injected between the pixel electrode 17 and the common electrode 23. Although not shown, an alignment layer is formed on the upper portion of the pixel electrode 17 and the lower portion of the common electrode 23, respectively. Determine the initial arrangement of the liquid crystal molecules.

Subsequently, in the second region B, a seal pattern 27 is formed between the first substrate 10 and the second substrate 20 to form a gap for injecting the liquid crystal and prevent leakage of the injected liquid crystal. Formed. Here, the gate insulating film 12, the protective layer 16, and the common electrode 23 of the second substrate 20 on the first substrate 10 extend to the second region B. As shown in FIG.

Such a liquid crystal display includes a process of manufacturing a lower array substrate on which thin film transistors and pixel electrodes are arranged, a process of manufacturing an upper color filter substrate including a color filter and a common electrode, an arrangement of two manufactured substrates, and a liquid crystal material It is formed by a liquid crystal cell process consisting of the injection and encapsulation of a, and the attachment of a polarizing plate.

The liquid crystal display is classified into a transmission type and a reflection type according to the position of the light source.

The transmissive liquid crystal display device displays an image by arranging a backlight on the back of the liquid crystal panel and injecting light from the backlight into the liquid crystal panel to adjust the amount of light according to the arrangement of the liquid crystals. In this case, the pixel electrode 17 and the common electrode 23, which are electric field generating electrodes of the liquid crystal display, are made of a transparent conductive material, and the two substrates 10 and 20 should also be made of a transparent substrate.

On the other hand, the reflective liquid crystal display is a form of adjusting the light transmittance according to the arrangement of the liquid crystal by reflecting the external natural light or artificial light. In the reflective liquid crystal display, the lower pixel electrode 17 is formed of a conductive material having good reflection, and the upper common electrode 23 is formed of a transparent conductive material to transmit external light. In this case, the first substrate 10 may be made of a material that is opaque or low in transparency.

The transmissive liquid crystal display uses an artificial back light source, so that bright images can be realized even in a dark environment. However, the power consumption of the transmissive liquid crystal display is large. Since the structure is dependent on the power consumption is less than the transmissive liquid crystal display device, but can not be used in a dark place has the disadvantage.

Therefore, recently, a liquid crystal display device having both a reflection and a transmission has been proposed and developed as a device capable of appropriately selecting and using two modes according to a necessary situation.

FIG. 2 is a cross-sectional view of a general transflective liquid crystal display, and illustrates a portion corresponding to one pixel area. FIG.

As shown in FIG. 2, a pixel electrode 32 is formed on the lower substrate 31 including a thin film transistor (not shown) which is a switching element. The pixel electrode 32 is composed of two parts, the transmission part 32a and the reflection part 32b. A hole is formed in the reflection part 32b, and the hole of the reflection part 32b is formed by the transmission part 32a. Corresponds. The electrode of the transmission part 32a is made of a transparent conductive material having a relatively high light transmittance, such as indium-tin-oxide (ITO) or indium-zinc-oxide (IZO). The electrode of the reflector 32b is made of a material having a low resistance and a high reflectance, such as aluminum (Al).

The upper substrate 33 is disposed on the lower substrate 31 at a predetermined distance from the lower substrate 31, and the color filter 34 is disposed at a position corresponding to the pixel electrode 32 on the inner surface of the upper substrate 33. Is formed. The common electrode 35 made of a transparent conductive material is formed on the color filter 34.

A horizontally oriented liquid crystal layer 37 is inserted between the upper substrate 33 and the lower substrate 31.

Outside the two substrates 31 and 33, first and second retardation films (QWPs) 41 and 42 are disposed, respectively. The QWPs 41 and 42 function to change the polarization state of light. That is, the linear flat light is changed to left or right polarized light, and the left or right polarized light is changed to linear polarized light.

The lower polarizing plate 43 and the upper polarizing plate 44 are disposed outside the first and second QWPs 41 and 42, respectively. Here, the polarization axis of the upper polarizing plate 44 has an angle of 90 degrees with respect to the polarization axis of the lower polarizing plate 43.

In addition, the backlight 45 is disposed outside the lower polarizer 43, that is, below the lower polarizer 43, and is used as a light source in a transmission mode.

As described above, in the transflective liquid crystal display device, the pixel electrode is composed of a reflecting portion and a transmitting portion, and can be appropriately used as necessary.

Meanwhile, the liquid crystal display further includes a driver for driving the thin film transistor.                         

The driver unit includes a driver circuit (hereinafter referred to as a driver integrated circuit) for applying a signal to the wiring of the liquid crystal display device, and according to a method of packaging the driver IC in the liquid crystal display device, the chip on glass (COG: chip on glass), tape carrier package (TCP), chip on film (COF).

The COG method is a method of bonding a driver IC to an array substrate of a liquid crystal display device and directly connecting the output electrode of the driver IC to a wiring pad on the array substrate. The COG method is simple in structure and simple in manufacturing process. There is an advantage.

The array substrate structure of the liquid crystal display device formed by such a COG method is briefly shown in FIG. 3.

As shown, the array substrate 50 of the liquid crystal display device is divided into a display area 52 inside the dotted line on which an image is displayed and a non-display area 54 outside the dotted line.

A plurality of gate wires 61 and data wires 62 are formed in the display area 52. The gate wires 61 and the data wires 62 intersect to define a pixel area. Although not shown, a thin film transistor is positioned at a portion where the gate wiring 61 and the data wiring 62 cross each other, and the thin film transistor displays an image by switching a signal to the pixel electrode in the pixel region.

Next, gate and data link lines 63 and 64 connected to the gate line 61 and the data line 62 are formed in the non-display area 54, and the gate and data link lines 63 and 64 are formed. One end is connected to the gate driver IC 70 and the data driver IC 80 mounted on the array substrate 50, respectively. The gate driver IC 70 and the data driver IC 80 are connected to an external printed circuit board (PCB) (not shown), respectively, via a flexible printed circuit (FPC) (not shown). It is. In the printed circuit board (PCB), a plurality of elements such as integrated circuits are formed on a substrate to generate various control signals, data signals, and the like for driving the liquid crystal display. At this time, the printed circuit board may be formed of a gate portion and a data portion, respectively, which are connected to each other by an FPC so that the gate signal and the data signal are organically connected, thereby supplying a signal.

Meanwhile, in the recent COG method of forming a driver IC on an array substrate, in order to simplify the structure and manufacturing process of the FPC, a line on glass (hereinafter, LOG) connecting the gate driver IC and the data driver IC on the array substrate is provided. Method has been proposed and used.

The structure of the array substrate of the liquid crystal display using the LOG method is illustrated in FIG. 4, except that the LOG wiring is the same as that shown in FIG. 3, the same reference numerals are assigned to the same parts, and the description thereof will be described. It will be omitted.

As shown in the figure, in the array substrate 50 of the liquid crystal display device using the LOG method, there are many LOG wirings 90 connecting the gate driver IC 70 and the data driver IC 80 to the non-display area 54. Dogs are formed. The LOG wirings 90 may replace the gate driver and the data driver by FPC, thereby simplifying a manufacturing process and reducing costs.

In recent years, as the size and size of liquid crystal displays have been increased, the length of the wiring is increased and its width is reduced, thereby increasing the probability of signal delay. Therefore, in order to reduce the resistance of the wiring, the wiring must be formed using a low resistance material. Since the specific resistance of aluminum is relatively low, aluminum or an aluminum alloy is frequently used as the material of the gate wiring.

On the other hand, since LOG wiring replaces conventional FPC, which has excellent electrical conductivity, LOG wiring must also have very low resistance. Among the LOG wiring, the wiring that delivers the gate low signal has a resistance of several ohms. Required. Therefore, it should be formed using a low-resistance material. As mentioned above, since the gate wiring is formed of aluminum or an aluminum alloy material, the LOG wiring may be formed together when the gate wiring is formed, thereby reducing the process.

An enlarged view of the LOG wiring portion is shown in FIGS. 5 and 6. FIGS. 5 and 6 are plan and cross-sectional views, respectively, of part C of FIG. 4, and FIG. 6 is taken along line VI-VI in FIG. 5. Corresponds to the cross section.

As shown in the figure, a LOG wiring 90 is formed on the insulating substrate 60, and first and second insulating films 65 and 66 are formed thereon to cover the LOG wiring 90. Here, the LOG wiring 90 is formed together with the formation of a gate wiring (not shown) using aluminum or an aluminum alloy, and the length of the wiring is minimized and the width is maximized in order to reduce the resistance. At this time, the first insulating film 65 is a gate insulating film covering the gate wiring, and the second insulating film 66 is a protective layer for protecting the thin film transistor (not shown).

On the other hand, here, seven LOG wirings 90 are formed, which may be changed depending on other conditions such as the structure of the circuit as the number currently being used.

In this way, the LOG wiring is formed of aluminum or an aluminum alloy together with the gate wiring, thereby reducing the number of steps while reducing the resistance of the LOG wiring.

However, FPC is formed by using copper. Since the resistivity of aluminum is about 1.6 times that of copper, LOG wiring is still a big problem compared to FPC.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described conventional problems, and an object of the present invention is to provide a liquid crystal display device having a COG structure in which a driving circuit is formed on an array substrate. An array substrate for a display device is provided.

In the array substrate for a liquid crystal display device according to the present invention for achieving the above object, a plurality of gate wirings and data wirings defining a pixel region by crossing on the display region of an insulating substrate defined as a display region and a non-display region. And a thin film transistor is connected with the gate wiring and the data wiring. Next, a pixel electrode connected to the thin film transistor and made of an opaque conductive material is positioned in the pixel region, and a gate driving circuit and a data driving circuit for applying a signal to the gate wiring and the data wiring are disposed on the non-display area, respectively. Subsequently, a LOG wiring formed of first and second wirings that connect the gate and the data driving circuit and insulate and overlap each other is formed on the non-display area.

Here, the first wiring of the LOG wiring may be made of the same material as the gate wiring, and the second wiring of the LOG wiring may be made of the same material as the pixel electrode. At this time, the LOG wiring is preferably made of any one of aluminum and aluminum alloy.

In addition, the pixel electrode may further include an opening therein.

As described above, in the present invention, in the reflective or semi-transmissive liquid crystal display array substrate using the COG method, the LOG wiring is formed by forming the gate wiring and the pixel electrode when applying the LOG method which can simplify the process and reduce the cost. By forming each time, the wiring width can be formed wide to reduce the resistance of the wiring and the manufacturing process is not increased.

Since the LOG wiring must be small in resistance, its length is short and its width is made wide by using low resistance material.Because the gate wiring is formed by using relatively small resistivity aluminum, LOG wiring at the time of forming such wiring is not necessary to increase the process. Form together. However, since the LOG wiring still has a larger resistance value than the FPC, a smaller resistance is required. Therefore, when the LOG wiring is formed by one layer, there is a limit in reducing the LOG wiring.

By the way, in the reflective or semi-transmissive liquid crystal display device, the pixel electrode is made of an opaque electrode. In this case, the pixel electrode is formed using aluminum or aluminum alloy having high reflectance. Therefore, in the present invention, the LOG wiring resistance can be reduced by forming the LOG wiring at the gate wiring and the pixel electrode formation in the reflective or semi-transmissive liquid crystal display to form a wide wiring width.

Hereinafter, an array substrate for a liquid crystal display according to an exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings.

First, FIG. 7 is a plan view of an array substrate according to the present invention.

As shown, the array substrate 100 according to the present invention is divided into a display area 112 and a non-display area 114. Here, the display area 112 is an area for displaying an image, and the non-display area 114 is an area in which a circuit for applying a signal to the display area 112 is disposed.

In the display area 112, a plurality of gate lines 121 having a horizontal direction and a plurality of data lines 122 having a vertical direction are formed. The gate wiring 121 and the data wiring 122 cross each other to define a pixel region, and the thin film transistor 123 serving as a switching element is formed in the region where the gate wiring 121 and the data wiring 122 cross each other. The pixel electrode 124 connected to the thin film transistor 123 is formed in the pixel area, and the thin film transistor 123 switches the signal of the data line 122 to the pixel electrode 124 according to the signal of the gate line 121. do. Here, the array substrate 100 according to the present invention is used in a reflective or semi-transmissive liquid crystal display device, and the pixel electrode 124 is made of aluminum or an aluminum alloy material, and the gate wiring 121 is also made of aluminum or aluminum. Made of alloy material. Although not illustrated, an opening is formed in the pixel electrode 124 made of aluminum or an aluminum alloy when used in a transflective liquid crystal display.

Next, a plurality of gate and data link lines 131 and 132, a gate driver IC 140, and a data driver IC 150 are formed in the non-display area 114, respectively, and the gate driver IC 140 and the data driver are formed. The IC 150 is connected to the gate wiring 121 and the data wiring 122 through the gate and the data link lines 131 and 132, respectively.

The gate driver IC 140 and the data driver IC 150 are connected by a LOG wiring 160 formed on the non-display area 114 of the array substrate 100.

An enlarged view of the LOG wiring is shown in FIGS. 8 and 9, where FIG. 8 is an enlarged plan view of part D of FIG. 7, and FIG. 9 is a cross-sectional view taken along the line VII-VII of FIG. 8.

As shown, the first to third LOG wirings 161, 162, and 163 are formed on the insulating substrate 120 at regular intervals, and the gate insulating layer 125 and the protective layer 126 are sequentially formed thereon. It is. Next, fourth to seventh LOG wirings 164, 165, 166, and 167 are formed at a predetermined interval on the passivation layer 126. Here, the first to third LOG wirings 161, 162, and 163 are made of the same material as the gate wiring (121 in FIG. 7), and the fourth to seventh LOG wirings 164, 165, 166, and 167 are made of the same material. It is made of the same material as the pixel electrode (124 in FIG. 7), all made of aluminum or an aluminum alloy material. In addition, the gate insulating layer 125 may be formed of an inorganic insulating layer such as a silicon nitride layer or a silicon oxide layer, and the protective layer 126 may be formed of an organic insulating layer such as an acrylic resin.

In the present invention, since two insulating layers are formed between the first to third LOG wirings 161, 162 and 163 and the fourth to seventh LOG wirings 164, 165, 166 and 167, the LOG wiring 161, Even if the 162, 163, 164, 165, 166, and 167 are formed to overlap each other, problems such as distortion of the signal can be prevented.

In the present invention, since the first to third LOG wirings 161, 162, and 163 have a wider width than the fourth to seventh LOG wirings 164, 165, 166, and 167, the resistance is smaller. The location may change. That is, the first to third LOG wirings 161, 162, and 163 may be formed on the upper portion, and the fifth to seventh LOG wirings 164, 165, 166, and 167 may be formed on the lower portion. In addition, it is preferable that the gate low signal line requiring the smallest resistance among the LOG wirings is one of the first to third LOG wirings 161, 162, and 163 having a wider width.

As described above, in the present invention, the LOG wirings 161, 162, 163, 164, 165, 166, and 167 are formed by dividing the gate wirings and the pixel electrodes during formation, respectively, so that the LOG wirings 161, 162, 163, 164, 165, and 166 are formed. 167) can increase the width by about two or more times compared to the prior art. Therefore, the resistance of the LOG wiring can be reduced to 1/2 or less.                     

Here, the number of LOG wirings (161, 162, 163, 164, 165, 166, 167) is set to seven, but as mentioned above, the number of LOG wirings (161, 162, 163, 164, 165, 166, 167) is mentioned. Can be changed.

However, since the aluminum-based material may be easily corroded by chemicals and the like, it is possible to prevent the LOG wiring from being damaged by further forming a metal layer such as molybdenum (Mo) mainly on the aluminum or aluminum alloy.

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

In the present invention, in the reflective or semi-transmissive liquid crystal display array substrate using the COG method, when applying the LOG method that can simplify the process and reduce the cost, LOG wiring is formed in different layers to reduce the wiring width. By making it wider, the resistance of a wiring can be reduced. In this case, the LOG wirings are formed together when the gate wirings and the pixel electrodes formed of the low resistance material are formed, respectively, so that the manufacturing process is not increased.

Claims (5)

An insulating substrate defined by a display area and a non-display area; A plurality of gate lines and data lines formed on the display area and crossing each other to define a pixel area; A thin film transistor connected to the gate line and the data line; A pixel electrode positioned in the pixel region and connected to the thin film transistor and made of an opaque conductive material; A gate driving circuit and a data driving circuit disposed on the non-display area and respectively applying a signal to the gate wiring and the data wiring; A LOG wiring disposed on the non-display area and connecting the gate and the data driving circuit, the first wiring and the second wiring being insulated and overlapping each other; Array substrate for a liquid crystal display device comprising a. The method of claim 1, And the first wiring of the LOG wiring is made of the same material as the gate wiring. The method of claim 2, And a second wiring of the LOG wiring is made of the same material as that of the pixel electrode. The method of claim 3, wherein The LOG wiring is an array substrate for a liquid crystal display device made of any one of aluminum and aluminum alloy. The method of claim 4, wherein The pixel electrode further includes an opening therein.

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