KR100709502B1 - A method for fabricating reflective and transflective liquid crystal display device and the same - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a structure of an array substrate for a reflection type and a reflection type liquid crystal display device.

When the neighboring pixel electrodes of the array substrate are alternately arranged up and down with an insulating layer interposed therebetween, the gate electrodes and the data wiring portions of the array substrate can be extended to form the pixel electrodes.

Therefore, an increase in luminance due to an increase in openings, a contrast improvement, and an image quality improvement effect can be obtained.

Description

Reflective and transmissive liquid crystal display device and method for manufacturing the same {a method for fabricating reflective and transflective liquid crystal display device and the same}             

1 is an exploded perspective view illustrating a general reflective transmissive liquid crystal display device;

FIG. 2 is an enlarged plan view schematically showing some pixels of a typical reflective liquid crystal display array substrate;

3 is a cross-sectional view taken along line III-III ′ of FIG. 2;

4 is an enlarged plan view schematically illustrating some pixels of a general array of reflective transmissive liquid crystal display devices;

FIG. 5 is a cross-sectional view taken along line VV ′ of FIG. 4;

6 is an enlarged plan view schematically showing some pixels of an array substrate for a reflective liquid crystal display device according to the present invention;

7A to 7C are cross-sectional views taken along the line VI-VI ′ and VIII-VIII of FIG. 6, according to a process sequence of the present invention.

8 is an enlarged plan view schematically showing some pixels of an array substrate for a reflective transmissive liquid crystal display device according to the present invention;                 

9A to 9D are cross sectional views taken along the lines VII-VII and VII-VII of FIG. 8 and shown in the process sequence of the present invention.

<Explanation of symbols for main parts of drawing>

T1: Nth thin film transistor T2: N + 1th thin film transistor

119b: reflective electrode 135`: drain electrode

147: second protective layer 149: drain contact hole

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and in particular, to a reflective liquid crystal display device using a reflection mode, and a reflective liquid crystal display device capable of selectively using a reflection mode and a transmission mode. device).

In general, the reflective liquid crystal display device does not require an additional light source device such as a backlight since the light source can be replaced with an external light source.

In addition, the reflective liquid crystal display device has the functions of a transmissive liquid crystal display device and a reflective liquid crystal display device at the same time, it is possible to use both backlight light and external natural light or artificial light source to limit the surrounding environment There is an advantage that can reduce the power consumption (power consumption).

The structure and driving method of the liquid crystal display device will be described using, for example, the reflection-transmissive liquid crystal display device among the two types of liquid crystal display devices.

FIG. 1 is an exploded perspective view illustrating a general reflective transmissive color liquid crystal display device.

As shown in the drawing, a general reflection-transmissive liquid crystal display 11 includes a color filter 17 including a black matrix 16, an upper substrate 15 having a transparent common electrode 13 formed on the color filter, and a pixel region. A pixel electrode 19 having a transmissive portion A and a reflecting portion C formed at the same time as the pixel region 19 and a lower substrate 21 having a switching element T and an array wiring formed thereon. ) And the lower substrate 21 are filled with the liquid crystal 23.

The lower substrate 21 is also referred to as an array substrate, and the thin film transistor T, which is a switching element, is positioned in a matrix type, and the gate wiring 25 and the data wiring 27 passing through the plurality of thin film transistors cross each other. Is formed.

In this case, the pixel area P is an area where the gate line 25 and the data line 27 cross each other.

In the above configuration, if the transparent pixel electrode is removed and no transmission hole is formed in the reflective electrode or the reflecting plate, the structure of the reflective liquid crystal display device becomes rough.

2 is a schematic plan view showing some pixels of an array substrate for a reflective liquid crystal display device.                         

As shown in the drawing, the array substrate for a reflective liquid crystal display device is configured such that the gate line 25 and the data line 27 vertically intersect in a plane to define the pixel region P, and at the intersection of the two lines The switching element T is formed.

Generally, the switching element T is formed by forming a thin film transistor (TFT) including a gate electrode 32, a source electrode 33, a drain electrode 35, and an active layer 34. do.

The pixel electrode 19 is positioned on the pixel region P, and contacts the drain electrode 35 of the thin film transistor to drive the liquid crystal (23 of FIG. 1).

In the reflective mode, the pixel electrode 19 is a reflective electrode and is formed using an opaque conductive metal having excellent reflectance. Such an opaque metal material may be, for example, an aluminum-based metal including aluminum (Al) and an aluminum alloy (for example, AlNd).

The operation mode of the reflective liquid crystal display device including the array substrate having such a configuration will be briefly described.

As the light source of the reflection mode uses an external light source as described above, the light incident from the outside to the upper substrate (not shown) of the liquid crystal panel is reflected by the reflective electrode 19 formed on the array substrate 21 and is affected by the voltage. As the light passes through the aligned liquid crystal (not shown), the light is emitted in a state where the polarization state of the light is changed according to the birefringence characteristic of the liquid crystal.

In this way, the light exiting the liquid crystal (not shown) passes through the color filter (not shown) to color the color filter to perform a visible color display function of red / green / blue color.

A cross-sectional structure of the reflective liquid crystal display device having such a configuration will be described below with reference to FIG. 4.

3 is a cross-sectional view taken along line IV-IV ′ of FIG. 2.

As shown, first, a gate electrode 32 and a gate wiring (25 in FIG. 2) are formed on the substrate 21, and the data wiring 27, the source electrode 33, and the drain electrode 35 are formed as described above. The gate insulating film 41 is formed between the gate electrode 32.

The active layer 34 overlaps the source electrode 33 and the drain electrode 35, respectively.

After forming the thin film transistor T including each electrode and the active layer, a protective layer 43 made of an insulating material for protecting the thin film transistor is formed.

Next, the protective layer 43 is patterned to form a drain contact hole 45 on the drain electrode 35, thereby forming a reflective electrode 19 in contact with the drain electrode 35. .

In this configuration, the liquid crystal (not shown) is positioned in front of the substrate 21, but only the liquid crystal positioned on the reflective electrode 19 is driven.

Thus, as shown, the region A between the reflective electrode 19 and the reflective electrode is excluded from the driving region.

In particular, a gap is formed between the pixel electrode and the data wiring in the region A in consideration of a design error. When a voltage is applied, the liquid crystal positioned in the region has a different orientation from that of the liquid crystal positioned in the pixel region. In addition, even when the black state is to be shown, the light leakage phenomenon of the light is generated.

Therefore, when the black matrix fabricated on the upper substrate is formed, a large area is formed so as to cover all of the abnormal driving regions such as the lower region A, thereby reducing the aperture ratio of the liquid crystal panel. Such a phenomenon also occurs in the array substrate for reflective transmissive liquid crystal display device described below.

4 is a partial plan view of an array substrate for a conventional transmissive liquid crystal display device.

As shown in FIG. 1, in the reflective transmissive liquid crystal display, as illustrated in FIG. 1, the transmissive portion A and the reflective portion B are simultaneously present in the pixel region P to operate in both the reflective mode and the transmissive mode. Structure.

The means used to define the reflecting portion and the transmitting portion may be formed directly on or below the reflective electrode (or reflecting plate) 19a including the transmission hole 51 and the reflective electrode 19a or the reflection It consists of the transparent pixel electrode 19b which may be formed through the insulating layer (not shown) between the electrode 19a.

The cross-sectional structure of such a structure is demonstrated below in FIG.

FIG. 5 is a cross-sectional view taken along the line VV ′ of FIG. 4. (See FIG. 4.)

First, the thin film transistor T including the gate electrode 32, the source electrode 33, and the drain electrode 35 is formed on the substrate 21, and then the first passivation layer 43 is formed on the thin film transistor. To form.                         

Next, a drain contact hole 45 is formed on the drain electrode 35 of the thin film transistor T, and at the same time, a position corresponding to the position of the transmission hole (51 in FIG. 4) formed in the pixel region P is formed. The protective layer 43 of the portion is etched from the surface in the direction of the substrate to form an etching groove 53. (The etching groove 53 may not be formed at this time.)

Next, the reflection is positioned on the pixel region P while contacting the drain electrode 35 through the drain contact hole 45 and includes a transmission hole 51 at a position corresponding to the etch groove 53. The electrode 19a is formed.

Next, the second protective layer 47, which is an insulating material, is formed on the reflective electrode 19a, and then patterned to form a reflective electrode (a portion of the portion contacting the drain electrode 35 through the drain contact hole 45). 19a) is exposed to a predetermined area.

Next, the transparent pixel electrode 19b is formed to be positioned on the pixel region P while contacting the reflective electrode 19a exposed between the patterned second protective layers 47.

By such a process, a conventional array substrate for a reflective transmissive liquid crystal display device can be manufactured.

In the above-described conventional reflective transmissive array substrate, there is an area between the reflective electrode including the transmissive hole and the reflective electrode in the same manner as the above-described reflective liquid crystal display device where the liquid crystal is positioned but does not operate.

Therefore, the conventional reflective liquid crystal display device or the reflective transmissive liquid crystal display device has a disadvantage in that the aperture ratio is lower than that of the general transmissive liquid crystal display device.

The present invention for solving such a problem is proposed a structure and method for activating the non-operation region between the electrode and the electrode to the operating area, the aperture ratio, brightness and contrast ratio (improved) is further improved Its purpose is to manufacture a reflective liquid crystal display and a reflective transmissive liquid crystal display.

According to an aspect of the present invention, an array substrate for a reflective liquid crystal display device includes: a substrate having first and second pixel regions adjacent to each other; A data line and a gate line intersecting each other vertically on the substrate to define the first and second pixel areas; First and second switching elements configured at intersections of the gate wiring and the data wiring; A first reflective electrode connected to the first switching element and formed on the first pixel region and extending above the gate wiring and the data wiring defining the first pixel region; An insulating film formed over the first reflective electrode; The second reflective electrode adjacent to the adjacent first reflective electrode on the second pixel region is formed on the gate and data lines on the insulating layer, and includes a second reflective electrode connected to the second switching element. .

The first and second reflective electrodes are formed of one selected from a group of conductive metals composed of aluminum and an aluminum-based alloy.

The insulating film interposed between the first and second reflective electrodes is formed of an insulating material having a dielectric constant of 3 or less.

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According to still another aspect of the present invention, an array substrate for a transflective liquid crystal display device includes: a substrate having first and second pixel regions adjacent to each other; A data line and a gate line intersecting each other vertically on the substrate to define the first and second pixel areas; First and second switching elements configured at intersections of the gate and data lines; A reflection plate including a transmission hole at a position corresponding to the first and second pixel areas, the reflection plate extending in an upper portion of the gate wiring line and the data wiring line so as to be connected to the whole; The gate wiring disposed on the reflective plate formed between the pixel areas, connected to the first switching device, formed on the first pixel area including the first switching device, and forming the first pixel area; A first transparent pixel electrode having an extended end thereof over the data line; An insulating film formed on the first transparent pixel electrode; A second transparent pixel connected to the second switching element over the insulating layer, the second transparent pixel being formed so that the first transparent pixel electrode and an end thereof coincide on the gate and data lines on the second pixel area including the second switching element; An electrode.

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

First Embodiment

6 is a plan view showing some pixels of an array substrate for a reflective liquid crystal display device according to a first embodiment of the present invention.

As illustrated, the gate line 125 and the data line 127 vertically intersect to define the pixel area P, and the switching element T is positioned at the intersection of the two wires.

The switching element T forms a thin film transistor including a gate electrode 132, a source electrode 133, and a drain electrode 135.                     

The reflective electrode 119 is formed on the pixel area, which is a pixel electrode in contact with the drain electrode 135.

In this case, the adjacent reflective electrodes 119 are formed in close proximity to each other in the up / down direction and the left / right direction. The reason for such a configuration is that the reflective electrodes 119 adjacent to each other are alternately formed up and down through an insulating layer (not shown), thereby minimizing the effects of the mutual electrodes by the insulating layers positioned between the adjacent reflective electrodes. Because it can.

At this time, the insulating layer (not shown) interposed between the two reflective electrodes 119 is a group of organic insulating materials composed of benzocyclobutene and acryl resin having a low dielectric constant. It is preferable to select and use one.

Hereinafter, a manufacturing process of an array substrate for a reflective liquid crystal display device according to a first embodiment of the present invention will be described with reference to the process cross-sectional views of FIGS. 7A to 7C.

7A to 7C are cross-sectional views taken along the line VI-VI ′ and VIII-VIII of FIG. 6, according to a process sequence.

First, as shown in FIG. 7A, one selected from the group of conductive metals including aluminum (Al), aluminum alloy, molybdenum (Mo), copper (Cu), tungsten (W), chromium (Cr), and the like on a substrate. Is deposited and patterned to form a gate wiring 125 and a gate electrode (132 in FIG. 6).

In this case, when the gate electrode 132 and the gate wiring 125 are made of aluminum, a structure in which other conductive metals protecting the aluminum wiring may be stacked.

Next, an inorganic insulating material group composed of a silicon oxide film (SiO ₂ ) and a silicon nitride film (SiN _x ) on the entire surface of the substrate 111 including the gate wiring (125 in FIG. 6) and the gate electrode 132. Accordingly, the gate insulating layer 141 is formed by depositing or applying one selected from the group of organic insulating materials including benzocyclobutene, acryl resin, and the like.

A pure amorphous silicon layer and an impurity amorphous silicon layer are stacked and patterned on the gate insulating layer 141 to form a semiconductor layer 134 in an island shape on the gate electrode 132.

Next, the conductive metal material as described above is deposited on the entire surface of the substrate 111 on which the semiconductor layer 134 is formed, and then patterned to cross the gate line 125 of FIG. A data line 127 defining P), a source electrode 133 connected to the data line 127, and a drain electrode 135 spaced apart from each other are formed.

As a result, a structure in which the gate wiring 125 and the data wiring 127 are formed on the substrate 111 and the thin film transistor T is formed at the intersection of the two wirings is obtained.

Next, as illustrated in FIG. 7B, the first protective layer 143, which is an insulating material, is formed on the entire surface of the substrate 111 on which the thin film transistor T is formed, and then patterned to correspond to each of the plurality of pixels. The first drain contact hole 145 is formed to expose a portion of the drain electrode 135 formed in the nth thin film transistor T1 among the thin film transistors T positioned.

Next, a conductive metal material such as aluminum (Al) and an aluminum alloy having low resistance and excellent reflectance is deposited and patterned on the substrate 111 on which the drain contact hole 145 is formed, and the nth thin film transistor T1 is formed. The first reflective electrode 119a is formed in contact with the drain electrode 135.

In this case, the first reflective electrode 119a is formed to extend over one side of the data line 127 and the gate line 125 of FIG. 6.

Next, as illustrated in FIG. 7C, the second protective layer 147, which is an insulating material, is formed on the entire surface of the substrate 111 on which the first reflective electrode 119a is formed and then patterned to form the nth thin film transistor. The first protective layer 143 and the second protective layer on the drain electrode 135 ′ of the n + 1 th thin film transistor T2 positioned in the up / down direction and the left / right direction adjacent to the T1. The second drain contact hole 149 is formed by simultaneously etching 147.

Next, a conductive metal having excellent reflectivity as described above is deposited and patterned on the second protective layer 147 to contact the second drain electrode 135 ′ through the second drain contact hole 149. The second reflective electrode 119b is formed.

In this case, the second reflective electrode 119b also extends above one side of the data line 127 and the gate line 125 of FIG. 6.

In such a configuration, the arbitrary reflective electrodes can be obtained by staggering up and down with four neighboring pixel electrodes with an insulating layer interposed therebetween.                     

Accordingly, the reflective electrodes 119a and 119b adjacent to each other are planarly extended to the upper portion of the gate line 125 and the data line 127 in a planar manner.

In this case, the reflective electrodes 119a and 119b may extend to the upper portion of the thin film transistor T.

In this manner, an array substrate for a reflective liquid crystal display device according to the present invention can be manufactured. According to the above-described configuration, since the non-driving region is minimized between the reflective electrode and the reflective electrode, an array substrate for a reflective liquid crystal display device having improved luminance and contrast ratio as well as aperture ratio can be manufactured.

-Second Example-

 8 is a plan view showing some pixels of an array substrate for a reflective transmissive liquid crystal display device according to a first embodiment of the present invention.

As illustrated, the gate line 125 and the data line 127 vertically intersect on the substrate to define the pixel region P, and the thin film transistor T exists at an intersection point of the two wires.

The pixel region P is defined as a transmissive portion A and a reflective portion B. For this purpose, a reflective electrode 118 including a transmissive hole 141 is employed, and a transparent portion is formed on the reflective electrode 118. The pixel electrodes 119a and 119b are formed.

The reflective electrode 118 is formed on the entire surface of the substrate 111, and the transmission hole 141 is formed in each pixel, and the drain electrode 135 of the thin film transistor T formed corresponding to each pixel is formed. A contact hole 143 is formed in a portion of the upper portion.

In this case, any transparent electrode 119a among the transflective electrodes including the reflective electrode 118 and the transparent pixel electrodes 119a and 119b is alternately arranged up and down with the transparent electrodes 119b of neighboring pixels.

Hereinafter, a manufacturing process for the configuration of FIG. 8 will be described with reference to FIGS. 9A to 9D.

9A to 9C are cross-sectional views illustrating a process sequence by cutting along lines VIII-VIII and VIII-VIII of FIG. 8.

First, since FIG. 9A is the same as the thin film transistor forming process of the reflective liquid crystal display, detailed description thereof will be omitted.

As illustrated, the thin film transistors T1 and T2 are formed on the substrate 111, and the data lines 127 defining the pixel area P are vertically intersected with the gate wiring 125 of FIG. 8. Form.

Next, as shown in FIG. 9B, after the above-described insulating material is deposited or coated on the entire surface of the substrate 111 on which the thin film transistors T1 and T2 are formed, the first protective layer 149 is formed. An etching groove 151 is formed by etching a position corresponding to the transmissive part defined in the pixel region P with a predetermined area.

Next, an opaque conductive metal having excellent reflectance is deposited on the first passivation layer 149 and then patterned to form a through hole 141 at a position corresponding to the etch groove 151, and the thin film transistor ( A contact hole 143 is formed to expose the lower first passivation layer 149 by etching a predetermined area corresponding to a portion of the drain electrode 135 formed in T). In such a configuration, the display region of the substrate 111 is largely covered by the reflecting plate 118. (In other words, the structure can obtain high reflectance.)

Next, as illustrated in FIG. 9C, an insulating material as described above is deposited on the reflective plate 118 on which the transmission hole 141 is formed to form a second protective layer 153 and pattern the thin film. The first protective layer 149 and the second protective layer 153 on the drain electrode 135 are simultaneously etched through the contact hole 143 formed in the reflector on the transistors T1 and T2, and the nth The first drain contact hole 161 is formed to expose the drain electrode 135 of the thin film transistor T1, and the drain of the thin film transistor T2 adjacent to the top, bottom, left, and right directions of the nth thin film transistor T1 is formed. The second drain contact hole 163 is formed to expose the electrode 135 ′.

Next, a transparent conductive metal group consisting of indium-tin-oxide (ITO) and indium-zinc-oxide (IZO) is selected on the second protective layer 153. One is deposited and patterned to form a first transparent pixel electrode 119a which contacts the drain electrode 135 through the first drain contact hole 161 formed on the Nth thin film transistor T1.

In this case, the first transparent pixel electrode 119a extends above the gate line 125 and the data line 127 formed to cross each other vertically.

Next, as shown in FIG. 9D, a third protective layer 165 is formed by depositing or applying the above-described insulating material on the entire surface of the substrate 111 on which the first transparent pixel electrode 119a is formed. . Next, the second drain contact hole 167 is etched by etching the n th thin film transistor T1 and the third protective layer 165 on the top, bottom, left, and right sides of the thin film transistor T2. Form.

Next, a selected one of the transparent conductive metal groups as described above is deposited and patterned on the third passivation layer 165 to form the drain electrode 135 ′ through the second drain contact hole 167. The second transparent pixel electrode 119b is formed on the pixel region P in contact with each other.

In this case, the second transparent pixel electrode 119b extends in the direction of the gate wiring and the date wiring, and is configured to be close to the first transparent pixel electrode in a plan view.

In this manner, the reflective transmission liquid crystal display device according to the present invention can be manufactured.

In the above-described configuration, since a reflector including transmissive holes is formed on most of the substrate, and the transparent pixel electrode is alternately arranged up and down close to each other through an insulating layer for each pixel, a large area of the substrate is operated. It can be configured as.

Therefore, a reflective liquid crystal display device and a reflective transmissive liquid crystal display device excellent in reflectance and luminance can be manufactured.

Therefore, since the array substrate for the reflective liquid crystal display device and the array for the reflective liquid crystal display device according to the present invention have a structure in which the non-driving region is minimized between the pixels, the reflectivity is excellent and the contrast and luminance can be obtained.

Claims (10)

A substrate having first and second pixel regions adjacent to each other; A data line and a gate line intersecting each other vertically on the substrate to define the first and second pixel areas; First and second switching elements configured at intersections of the gate wiring and the data wiring; A first reflective electrode connected to the first switching element and formed on the first pixel region and extending above the gate wiring and the data wiring defining the first pixel region; An insulating film formed over the first reflective electrode; A second reflective electrode formed on the second pixel region and adjacent to the first reflective electrode adjacent to the gate and data lines on the second pixel region, and connected to the second switching element; Array substrate for a reflective liquid crystal display device comprising a. The method of claim 1, And the first and second reflecting electrodes are formed of one selected from a group of conductive metals composed of aluminum and an aluminum-based alloy. The method of claim 1, The first and second switching elements may be thin film transistors including a gate electrode connected to the gate line, a gate insulating layer, an active layer, and a source electrode and a drain electrode connected to the data line spaced apart from each other on the active layer. Array board for display device. The method of claim 1, And the insulating layer interposed between the first and second reflective electrodes is formed of an insulating material having a dielectric constant of 3 or less. The method of claim 4, wherein And the insulating layer is one selected from the group of organic insulating materials consisting of benzocyclobutene (BCB) and acrylic resin. A substrate having first and second pixel regions adjacent to each other; A data line and a gate line intersecting each other vertically on the substrate to define the first and second pixel areas; First and second switching elements configured at intersections of the gate and data lines; A reflection plate including a transmission hole at a position corresponding to the first and second pixel areas, the reflection plate extending in an upper portion of the gate wiring line and the data wiring line so as to be connected to the whole; The gate wiring disposed on the reflective plate formed between the pixel areas, connected to the first switching device, formed on the first pixel area including the first switching device, and forming the first pixel area; A first transparent pixel electrode having an extended end thereof over the data line; An insulating film formed on the first transparent pixel electrode; A second transparent pixel connected to the second switching element over the insulating layer, the second transparent pixel being formed so that the first transparent pixel electrode and an end thereof coincide on the gate and data lines on the second pixel area including the second switching element; electrode Array substrate for a transmissive liquid crystal display device comprising a. The method of claim 6, And the reflecting plate is formed of one selected from a group of conductive metals composed of aluminum and an aluminum-based alloy. The method of claim 6, The first and second switching elements may be thin film transistors including a gate electrode connected to the gate line, a gate insulating layer, an active layer, and a source electrode and a drain electrode connected to the data line spaced apart from each other on the active layer. Array board for display device. The method of claim 6, And the insulating film interposed between the first transparent pixel electrode and the second transparent pixel electrode is formed of an insulating material having a dielectric constant of 3 or less. The method of claim 9, And the insulating film is one selected from the group of organic insulating materials consisting of benzocyclobutene (ben) and acrylic resin, and the like.

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