KR20060087929A - Liquid crystal display device and method of fabricating the same - Google Patents

Abstract

The liquid crystal display of the present invention and a method of manufacturing the same are for smoothly driving even in a low temperature environment by forming a heater line in a lower array substrate and allowing current to flow therethrough, which is divided into a pixel portion and a pixel outer portion. Array substrates; A plurality of gate lines and data lines arranged vertically and horizontally in a pixel portion of the array substrate to define a plurality of pixel regions; A flexible printed circuit board connected to an outer periphery of the array substrate to apply an external signal to the gate line and the data line; A color filter substrate bonded to the array substrate to form a liquid crystal display panel; And a first heater line formed on each of the data lines to transfer heat to the liquid crystal display panel.

Description

Liquid crystal display and its manufacturing method {LIQUID CRYSTAL DISPLAY DEVICE AND METHOD OF FABRICATING THE SAME}

1 is an exploded perspective view schematically illustrating a structure of a general liquid crystal display device.

2 is a plan view schematically illustrating an array substrate of a liquid crystal display according to a first exemplary embodiment of the present invention.

3 is a plan view showing a portion of the array substrate shown in FIG.

4A to 4G are cross-sectional views sequentially illustrating a manufacturing process along line III-III ′ of the array substrate illustrated in FIG. 3.

5A to 5C are cross-sectional views sequentially showing another manufacturing process of the array substrate shown in FIG. 3.

6 is a plan view schematically illustrating an array substrate of a liquid crystal display according to a second exemplary embodiment of the present invention.

** Explanation of symbols on the main parts of the drawing **

110,210: array substrate 190,290: flexible printed circuit board

191A, 191B, 291A, 291B: Current supply line 192A, 192B, 292A, 292B: Electrode part

195,295A, 295B: Heater Line

The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device and a method of manufacturing the same that can be driven in a low temperature environment.

Recently, with increasing interest in information display and increasing demand for using a portable information carrier, a lightweight flat panel display (FPD), which replaces a conventional display device, a cathode ray tube (CRT), is used. The research and commercialization of Korea is focused on. In particular, the liquid crystal display (LCD) of the flat panel display device is an image representing the image using the optical anisotropy of the liquid crystal, is excellent in resolution, color display and image quality, and is actively applied to notebooks or desktop monitors have.

In general, a liquid crystal display device displays a desired image by individually supplying data signals according to image information to liquid crystal cells arranged in a matrix form to adjust a light transmittance of the liquid crystal cells. to be.

Hereinafter, a liquid crystal display will be described in detail with reference to FIG. 1.

1 is an exploded perspective view schematically illustrating a structure of a general liquid crystal display device.

As shown in the figure, the liquid crystal display device is largely a color filter substrate 5 as a first substrate and an array substrate 10 as a second substrate, and the color filter substrate 5 and an array substrate. It consists of a liquid crystal layer (40) formed between (10).

The color filter substrate 5 includes a color filter C composed of red (R), green (G), and blue (B) sub-color filters (7) and the sub-color filters (7). ) And a black matrix 6 for blocking light passing through the liquid crystal layer 40 and a transparent common electrode 8 for applying a voltage to the liquid crystal layer 40.

The array substrate 10 has gate lines 16 and data lines 17 arranged vertically and horizontally to define the pixel region P. FIG. In this case, a thin film transistor (TFT) T, which is a switching element, is formed in an intersection region of the gate line 16 and the data line 17, and each pixel region P includes a pixel electrode 18. ) Is formed.

The pixel region P is a sub pixel corresponding to one sub color filter 7 of the color filter substrate 5. The color image is a sub-color filter 7 of the red, green, and blue colors. It is obtained by combining. That is, three subpixels of red, green, and blue are gathered to form one pixel, and the thin film transistor T is connected to the red and green subpixels, respectively.

In the liquid crystal display device configured as described above, when the liquid crystal display panel is exposed to the outside at a predetermined temperature or less, for example, about -40 to 0 ° C., the liquid crystal in the liquid crystal display panel is cooled and bubbles are generated. As a result, the dielectric anisotropy and its characteristics of the liquid crystal are changed, resulting in a problem that normal image expression is not achieved.

 An object of the present invention is to provide a liquid crystal display device and a method of manufacturing the same, which are capable of normal image expression even in a low temperature environment.

In addition, another object of the present invention is to provide a liquid crystal display device and a method for manufacturing the same, which can reduce the weight and thickness, and simplify the manufacturing process by forming a heater line in the array substrate that can be driven in a low temperature environment as described above. have.

Other objects and features of the present invention will be described in the configuration and claims of the invention described below.

In order to achieve the above object, the liquid crystal display device of the present invention comprises an array substrate divided into a pixel portion and a pixel outer portion; A plurality of gate lines and data lines arranged vertically and horizontally in a pixel portion of the array substrate to define a plurality of pixel regions; A flexible printed circuit board connected to an outer periphery of the array substrate to apply an external signal to the gate line and the data line; A color filter substrate bonded to the array substrate to form a liquid crystal display panel; And a first heater line formed on each of the data lines to transfer heat to the liquid crystal display panel.

In addition, the manufacturing method of the liquid crystal display device of the present invention comprises the steps of providing a first substrate and a second substrate divided into a pixel portion and the pixel outer portion; A plurality of gate lines including a gate electrode, a plurality of data lines including a source electrode, a pixel electrode formed at an intersection region of the gate line and the data line, and electrically connected to the pixel electrode of the first substrate; Forming a switching element comprising a drain electrode and a channel layer forming a conductive channel between the source electrode and the drain electrode; Forming a first heater line on each of the data lines; Coupling a flexible printed circuit board to an outer periphery of the pixel of the first substrate; And bonding the first substrate and the second substrate to each other.

Hereinafter, exemplary embodiments of a liquid crystal display and a method of manufacturing the same according to the present invention will be described in detail with reference to the accompanying drawings.

In general, a liquid crystal display panel is manufactured by bonding a thin film transistor array substrate and a color filter substrate to each other at regular intervals, and filling a liquid crystal in a predetermined cell gap between the two substrates.

On the array substrate, gate lines are formed in parallel with the data lines arranged in parallel in the horizontal direction, and intersect the data lines, and a pixel is formed in the pixel area where the data lines and the gate lines intersect. Is defined.

In this case, the pixel includes a switching device electrically connected to the gate lines and the data lines, and a scan signal supplied through the gate lines from a gate driver integrated circuit is applied every gate line. When the switching element corresponding to the gate line is turned on, a video signal supplied through the data lines from the data driver integrated circuit is applied to the pixel.

The gate / data driving circuit receives a signal from a printed circuit board (PCB). The printed circuit board receives an external signal and converts the signal into a signal suitable for the operation of the liquid crystal display panel. Supply to the data drive circuit.

In order to enable such a series of processes, a printed circuit board, a gate / data driving circuit, and a liquid crystal display panel should be electrically connected to each other. There is a chip-on-glass method (COG).

The COG method is a technology in which a gate / data driving circuit is directly mounted on a substrate of a liquid crystal display panel, and has an advantage of thinning the liquid crystal display panel.

Hereinafter, the COG type liquid crystal display panel will be described in detail with reference to the accompanying drawings.

FIG. 2 is a plan view schematically illustrating an array substrate of a liquid crystal display according to a first exemplary embodiment of the present invention, and illustrates an array substrate of a liquid crystal display of a COG type.

As shown in the figure, data lines (not shown) and gate lines (not shown) are arranged parallel to each other on the array substrate 110 in a vertical direction, and in the same direction as the data lines on the data lines. Heater lines 195 are arranged.

At this time, when the array substrate 110 and the color filter substrate (not shown) are bonded to each other, a portion of the array substrate 110 does not correspond to the color filter substrate and is exposed to the outside. This is referred to as region 165.

A gate driver circuit (not shown) connected to the gate line and a data driver circuit (not shown) connected to the data line are mounted in the pad region 165 of the array substrate 110.

In addition, an input pad (not shown) and an output pad (not shown) are formed in the pad region 165 in which the driving circuit is to be mounted on the array substrate 110, so as to correspond to the input / output terminals of the driving circuit, respectively. Is connected.

The input pad of the pad region 125 receives a signal from a flexible printed circuit (FPC) 190 connected to the array substrate 110 and supplies the signal to the driving circuit. It is for supplying the output of the driving circuit to the gate line and the data line.

In the dummy part of the flexible printed circuit board 190, current supply lines 191A and 191B for supplying current to the heater line 195 are formed, wherein each of the current supply lines 191A, 191B is electrically connected to the upper and lower electrode portions 192A and 192B outside the pixel portion 160. In this case, the upper and lower electrode portions 192A and 192B are electrically connected to the heater lines 195 to supply current to the heater lines 195.

As described above, when the liquid crystal display panel is exposed to the outside at a predetermined temperature or less, for example, about −40 ° C. to 0 ° C., the liquid crystal in the liquid crystal display panel is cooled to generate bubbles. This bubble limits the dielectric anisotropy of the liquid crystal and prevents normal image expression. In order to prevent this, in the liquid crystal display panel of the present embodiment, when the temperature is exposed to an environment of below zero (0 ° or less), the current generated from the power supply unit by the detection of a sensor (not shown) is the current of the flexible printed circuit board 190. The supply lines 191A and 191B and the upper and lower electrode portions 192A and 192B are supplied to the heater lines 195. The heater lines 195 generate resistance by such a current, and the heat generated by the resistance is supplied to the liquid crystal display panel so that the liquid crystal is not cooled. Here, as the material of the heater line 195, a conductive material such as molybdenum, chromium, aluminum, and indium tin oxide (ITO) may be used, and the thickness thereof may be about 300 to 2000 kPa. .

As described above, the liquid crystal display according to the present exemplary embodiment forms current supply lines 191A and 191B in the dummy portion of the flexible printed circuit board 190 and heats the heater lines 195 in the pixel portion 160 of the array substrate 110. After the formation, current is supplied to the heater lines 195 to drive the liquid crystal display even in a low temperature environment.

In addition, as described above, the current supply lines 191A and 191B for supplying current to the heater lines 195 need only be formed in the dummy part of the flexible printed circuit board 190 to supply a heater current. There is also the advantage of not having to attach a flexible printed circuit board.

Meanwhile, the heater lines 195 may be formed above the data lines as described above, which will be described in detail below.

3 is a plan view illustrating a portion of the array substrate illustrated in FIG. 2.

At this time, in the actual liquid crystal display device, N gate lines and M data lines cross each other, and there are M × N pixels. However, only the (m, n) -th pixel is shown in the figure for simplicity.

As shown in the drawing, the array substrate 110 includes an n-th gate line 116n to which a scan signal is applied from an external driving circuit (not shown), an m-th data line 117m to which an image signal is applied, A thin film transistor, which is a switching element formed at an intersection of the gate line 116n and the data line 117m, and a pixel electrode 118 connected to the thin film transistor.

The thin film transistor includes a gate electrode 121 connected to the gate line 116n, a source electrode 122 connected to the data line 117m, and a drain electrode 123 connected to the pixel electrode 118. In addition, the thin film transistor may include a first insulating film (not shown) for insulating the gate electrode 121 and the source / drain electrodes 122 and 123 and the source electrode by a gate voltage supplied to the gate electrode 121. And a semiconductor layer (not shown) forming a conductive channel between the 122 and the drain electrode 123. In this case, a second insulating film (not shown) having a contact hole 140 is formed on the drain electrode 123, and the drain electrode 123 and the pixel electrode 118 are electrically connected through the contact hole 140. To be.

In this case, heater lines 195 are formed on the data lines 117m and 117m + 1 in the same direction as the data lines 117m and 117m + 1 to draw current from a current supply line (not shown) outside the pixel portion. It is supplied with heat to generate heat.

The heater lines 195 may be formed using a transparent conductive material for the pixel electrode when the pixel electrode 118 is formed, or may be formed of a low resistance conductive material such as molybdenum and aluminum.

In addition, a portion of the pixel electrode 118 extends toward the n-1 th gate line, that is, the front gate line 116n-1, to form a storage electrode 118 ', and the storage electrode 118' is the front end. A portion of the gate line 116n-1 is overlapped to form a storage capacitor.

The storage capacitor serves to maintain the pixel voltage charged in the pixel electrode 118 until the next pixel voltage is charged.

EMBODIMENT OF THE INVENTION Hereinafter, the manufacturing process of the array substrate of this invention is demonstrated in detail with reference to drawings.

4A to 4G are cross-sectional views sequentially illustrating a manufacturing process along line III-III ′ of the array substrate illustrated in FIG. 3.

In this case, the present embodiment has been described using four mask processes, that is, four mask processes for forming an array substrate using four photolithography processes, but the present invention is not limited thereto. It can be applied regardless.

As shown in FIG. 4A, a gate electrode 121 and a gate line (not shown) are formed on a substrate 110 made of a transparent insulating material such as glass.

In this case, the gate electrode 121 and the gate line are formed by depositing a conductive material on the entire surface of the substrate 110 and patterning the same through a photolithography process (first mask process).

As shown in FIG. 4B, the first insulating film 115A, the amorphous silicon thin film 120, the n + amorphous silicon thin film 130, and the conductive film 150 are sequentially formed on the entire surface of the substrate 110.

Thereafter, as shown in FIG. 4C, a photosensitive film 180 made of a photosensitive material such as a photoresist is formed on the entire surface of the substrate 110 and the photosensitive film 180 is formed through a diffraction mask 170 including a slit region. Irradiate light.

In this case, the diffraction mask 170 is provided with a first transmission region (I) for transmitting all the light, a second transmission region (II) for transmitting only a part of the light, and a blocking region (III) for blocking all irradiated light. Only light transmitted through the mask 170 is irradiated to the photosensitive layer 180.

In the diffraction mask 170 used in the present embodiment, the second transmission region II has a slit structure, and the exposure dose irradiated through the second transmission region II transmits all the light. It becomes less than the exposure amount irradiated to. Therefore, when the photoresist film 180 is applied and then exposed and developed using the mask 170 having the slit region II partially formed on the photoresist layer 180, the thickness of the photoresist film remaining in the slit region II may be reduced. The thickness of the photosensitive film remaining in the first transmission region I or the blocking region III is different.

In this case, when the positive type photoresist is used as the photoresist layer 180, the thickness of the photoresist layer remaining in the slit region II is smaller than the thickness of the photoresist layer remaining in the blocking region III and the photoresist is negative. When the resin is used, the thickness of the photoresist film remaining in the slit region II is smaller than the thickness of the photoresist film remaining in the first transmission region I.

In this case, although a positive type photoresist is used in the present embodiment, the present invention is not limited thereto, and a negative type photoresist may be used.

Subsequently, after the photoresist film 180 exposed through the diffraction mask 170 is developed (second mask process), as shown in FIG. 4D, the blocking region III and the second transmission region II may be formed. Photosensitive film patterns 180A and 180B having a predetermined thickness remain in areas where all light is blocked or partially blocked by the light, and the photosensitive film is removed in the first transmission area I region where all of the light is irradiated to remove the conductive film. 150) The surface is exposed.

In this case, the first photoresist pattern 180A formed through the blocking region III is thicker than the second photoresist pattern 180B formed in the second transmission region II.

That is, the first photoresist layer pattern 180A having the first thickness remains on the source / drain electrode region (that is, the region where the source electrode and the drain electrode are to be formed through the etching process described later) in the drawing, and the source electrode region A second photoresist pattern 180B having a second thickness remains between the drain electrode region and the drain electrode region.

Thereafter, the photoresist patterns 180A and 180B formed as described above are used as masks to selectively remove the conductive layer 150, the n + amorphous silicon thin film 130, and the amorphous silicon thin film 120. 121. An active pattern 124 made of an amorphous silicon thin film is formed on the upper portion. In this case, an n + amorphous silicon thin film pattern 130 'made of n + amorphous silicon thin film 130' and a conductive film pattern 150 'made of conductive film are formed on the active pattern 124.

Subsequently, when the ashing process is performed to completely remove the second photoresist layer pattern 180B of the second transmission region II, as shown in FIG. 4E, the first photoresist layer pattern 180A of the blocking region may be The third photoresist pattern 180A 'having the third thickness removed by the thickness of the second photoresist pattern 180B of the second transmission region II remains.

Subsequently, when the remaining photoresist pattern 180A 'is used as a mask and the conductive layer pattern 150' and the n + amorphous silicon thin film pattern 130 'are selectively removed, an upper portion of the active pattern 124 is formed. The source electrode 122 and the drain electrode 123 are formed on the substrate.

In this case, the n + amorphous silicon thin film pattern 130 ′ is also patterned in the same form to connect the source / drain electrodes 122 and 123 to a predetermined region of the active pattern 124. And form 125.

When the n + amorphous silicon thin film pattern 130 'is etched, a portion of the surface of the amorphous silicon thin film constituting the active pattern 124 below is removed, since the amorphous silicon thin film transistor is formed as a back-channel etch type. to be.

As such, the active pattern 124 and the source / drain electrodes 122 and 123 may be formed through one mask process by using diffraction exposure, thereby reducing the number of mask processes. However, the present invention is not limited thereto, and the active pattern 124 and the source / drain electrodes 122 and 123 may be formed through separate mask processes, that is, two mask processes.

In this case, a portion of the source electrode 122 forms a data line 117m to define a pixel area crossing the gate line.

Next, as shown in FIG. 4F, a second insulating film 115B is formed on the entire surface of the substrate 110. Then, the second insulating film 115B is selectively patterned using a photolithography process (third mask process) to form a contact hole 140 exposing a part of the drain electrode 123.

As shown in FIG. 4G, the transparent conductive material is deposited on the entire surface of the substrate 110 and then patterned by using a photolithography process (fourth mask process) to form the drain electrode through the contact hole 140. A pixel electrode 118 that is electrically connected to 123 is formed, and a heater line 195 is formed on the data line 117m.

The pixel electrode 118 and the heater line 195 may be formed of a transparent conductive material having excellent transmittance such as indium tin oxide (ITO) or indium zinc oxide (IZO). have.

As described above, the heater line 195 of the present exemplary embodiment has an advantage of simplifying the manufacturing process by forming the pixel electrode 118 using the transparent conductive material for the pixel electrode. It may be formed of a conductive material different from (118), which will be described in detail through the following manufacturing process.

5A through 5C are cross-sectional views sequentially illustrating another manufacturing process of the array substrate illustrated in FIG. 3, and the same manufacturing process is performed up to the third mask process described above.

That is, as shown in FIG. 5A, a second insulating film 115B is formed on the entire surface of the substrate 110. The second insulating film 115B is selectively patterned using a photolithography process (a third mask process) to form a contact hole 140 exposing a part of the drain electrode 123.

Subsequently, as shown in FIG. 5B, a transparent conductive material is deposited on the entire surface of the substrate 110 and then patterned by using a photolithography process (a fourth mask process) to form the drain electrode through the contact hole 140. A pixel electrode 118 electrically connected to 123 is formed.

5C, after the third insulating film 115C is formed on the entire surface of the substrate 110, a heater line 195 is formed on the data line 117m using a conductive material.

In this case, the heater line 195 is formed by depositing low-resistance conductive materials such as molybdenum, aluminum, and chromium on the entire surface of the substrate 110, and then patterning the same through a photolithography process (a fifth mask process).

At this time, the present embodiment has been described using an example of the four mask process of fabricating the array substrate using the four mask process (or five mask process), the present invention is not limited to this, the present invention is a mask process Regardless of the number of apply.

In addition, in the above embodiment, an amorphous silicon thin film transistor using an amorphous silicon thin film as the channel layer is described as an example. However, the present invention is not limited thereto, and the present invention is not limited to the polycrystalline silicon thin film transistor using the polycrystalline silicon thin film as the channel layer. The present invention also applies to a liquid crystal display device having a.

In addition, the invention can be applied regardless of the mode of the liquid crystal display device, that is, a twisted nematic (TN) mode, an in-plane switching (IPS) mode, and a vertical alignment (VA) mode. .

In addition, the present invention can be used not only in liquid crystal display devices but also in other display devices fabricated using thin film transistors, for example, organic light emitting display devices in which organic light emitting diodes (OLEDs) are connected to driving transistors. have.

On the other hand, the liquid crystal display of the first embodiment has been described a case in which the heater line is formed on the data line, for example, but the present invention is not limited thereto, and the heater line may be formed below or above the gate line. have.

In addition, the heater line of the present invention may be formed both above the data line and below the gate line, and in this case, the electrode parts for supplying current to the heater line are formed at the left and right sides of the outer periphery of the pixel part. It demonstrates in detail through 2nd Example.

6 is a plan view schematically illustrating an array substrate of a liquid crystal display according to a second exemplary embodiment of the present invention.

As shown in the figure, data lines (not shown) and gate lines (not shown) are arranged parallel to each other on the array substrate 210 in a vertical direction, and in the same direction as the data lines on the data lines. First heater lines 295A are arranged and second heater lines 295B are arranged under the gate lines in the same direction as the gate lines.

In this case, a flexible printed circuit board 290 is connected to the array substrate 210, and a current for supplying current to the heater lines 295A and 295B to a dummy part of the flexible printed circuit board 290. Supply lines 291A and 291B are formed, and each of the current supply lines 291A and 291B is electrically connected to the left and right electrode portions 292A and 292B outside the pixel portion 260. In this case, the left and right electrode portions 292A and 292B are electrically connected to the heater lines 295A and 295B to supply current to the heater lines 295A and 295B.

Many details are set forth in the foregoing description but should be construed as illustrative of preferred embodiments rather than to limit the scope of the invention. Therefore, the invention should not be defined by the described embodiments, but should be defined by the claims and their equivalents.

As described above, the liquid crystal display device and the method of manufacturing the same of the present invention can form a heater line in the liquid crystal display panel to emit heat so that the liquid crystal display device can be normally driven even at a low temperature.

In addition, the heater line is formed in the array substrate by using the manufacturing process of the array substrate, thereby providing an effect of thinning and manufacturing process of the liquid crystal display device.

Claims (12)

An array substrate divided into a pixel portion and a pixel outer portion; A plurality of gate lines and data lines arranged vertically and horizontally in a pixel portion of the array substrate to define a plurality of pixel regions; A flexible printed circuit board connected to an outer periphery of the array substrate to apply an external signal to the gate line and the data line; A color filter substrate bonded to the array substrate to form a liquid crystal display panel; And And a first heater line formed on each of the data lines to transfer heat to the liquid crystal display panel. The liquid crystal display of claim 1, wherein the heater lines are arranged in the same direction as the data lines. The liquid crystal display of claim 1, further comprising a second heater line disposed below the gate line in the same direction as the gate line. 4. The liquid crystal display of claim 3, further comprising a pair of current supply lines formed in a dummy portion of the flexible printed circuit board. The liquid crystal display device of claim 4, further comprising a pair of electrode parts formed on the pixel outer portion of the array substrate to receive current from the current supply line. 6. The method of claim 5, wherein the pair of electrode parts are connected to both ends of the first heater line and both ends of the second heater line to supply current to the first heater line and the second heater line. A liquid crystal display device. Providing a first substrate and a second substrate divided into a pixel portion and a pixel outer portion; A plurality of gate lines including a gate electrode, a plurality of data lines including a source electrode, a pixel electrode formed at an intersection region of the gate line and the data line, and electrically connected to the pixel electrode of the first substrate; Forming a switching element comprising a drain electrode and a channel layer forming a conductive channel between the source electrode and the drain electrode; Forming a first heater line on each of the data lines; Coupling a flexible printed circuit board to an outer periphery of the pixel of the first substrate; And And attaching the first substrate and the second substrate to each other. The method of claim 7, further comprising forming a second heater line under each of the gate lines. The method of claim 7, wherein the first heater line is formed by using a conductive material for the pixel electrode when forming the pixel electrode. The method of claim 7, wherein the first heater line is formed by using an electrically conductive material such as molybdenum, chromium, and aluminum after forming an insulating film on the entire surface of the first substrate on which the pixel electrode is formed. . 10. The method of claim 8, further comprising forming a pair of current supply lines in the dummy portion of the flexible printed circuit board. The method of claim 11, further comprising: forming a pair of electrode parts formed on the pixel outer portion of the first substrate and receiving current from the current supply line and transferring the current to the first heater line and the second heater line. Method of manufacturing a liquid crystal display device comprising a.

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