KR100656694B1 - Transflective liquid crystal display device - 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 reflective transmissive liquid crystal display device. First, a reflective plate having a transmissive hole is formed on a pixel area, and a pixel electrode is formed on the reflective plate with an insulating layer interposed therebetween. And a reflection-transmissive liquid crystal display device in which the reflector is driven by a single electrode. First, there is an effect of preventing the distortion of the electric field caused by the step difference of the reflecting electrode formed by forming the reflector as the reflection electrode. There is an effect that the process is simplified by using a structure in which a pixel electrode is stacked only on the reflecting plate without performing a repetitive photolithography process for simultaneously forming a reflective electrode and a transmissive electrode.

In addition, by forming the reflector as a reflector, various expressions are possible on the reflector, thereby increasing the luminance of the liquid crystal display.

Description

Reflective liquid crystal display device             

1 is an exploded perspective view showing a part of a typical reflective liquid crystal display device;

2 is a cross-sectional view of a typical transflective liquid crystal display device;

3 is a partial plan view of an array substrate for a transmissive liquid crystal display device according to the prior art;

4 is a cross-sectional view taken along II-II and III-III of FIG. 3,

5 is a partial plan view of an array substrate for a liquid crystal display device according to the present invention;

6 is a cross-sectional view according to a first embodiment of the present invention cut along VI-VI and VIII-V of FIG. 5,

FIG. 7 is a cross-sectional view according to a second embodiment of the present invention taken along lines VI-VI and VIII-V of FIG. 5.

<Description of the symbols for the main parts of the drawings>

113: data wiring 117: reflector

119: gate electrode 120: gate insulating layer

121: source electrode 123: drain electrode

125: active layer 128: first protective layer

129: pixel electrode 131: second protective layer

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

In general, the transflective liquid crystal display device has the functions of a transmissive liquid crystal display device and a reflective liquid crystal display device, and is able to use both a backlight light and an external natural light source without being restricted by the surrounding environment. There is an advantage that can reduce power consumption (power consumption).

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

As shown in the drawing, a typical reflective transmissive liquid crystal display device 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. And a lower substrate 21 having an array wiring including a switching electrode T and a pixel electrode 19 having a transmissive portion 19a and a reflecting portion 19b formed at the same time on the P region and the pixel region. The liquid crystal 23 is filled between the 15 and the lower substrate 21.

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 region P is an area defined by the gate wiring 25 and the data wiring 27 intersecting, and the transmission portion 19a of the pixel electrode 19 formed on the pixel region P is transparent. It forms by forming a hole or a transparent electrode. (It is assumed in the text that a transparent electrode is formed in the transmission portion).

The reflective electrode for forming the reflective portion 19b of the pixel electrode 19 is formed using a conductive metal having excellent reflectance, and the transparent electrode for forming the transmissive portion 19a is indium-tin-oxide-. Oxide: ITO) uses a transparent conductive metal with relatively good light transmittance.

The operation characteristics of the reflective liquid crystal display device having such a configuration will be described with reference to FIG. 2 is a cross-sectional view showing a general reflective transmissive liquid crystal display device.

As shown in the drawing, the schematic reflection-transmissive liquid crystal display 57 includes an upper substrate 43 on which the common electrode 33 is formed, and a lower substrate on which a pixel electrode composed of the reflective electrode 49 and the transparent electrode 51 is formed. 53, a liquid crystal 56 filled between the upper substrate 43 and the lower substrate 53, and a backlight 41 positioned below the lower substrate 53.

When the reflective liquid crystal display device 57 having such a configuration is used in a reflective mode, most of the light is used as an external natural light or an artificial light source.

The operation of the transmissive reflection type liquid crystal display device in the reflective mode will be described with reference to the above-described configuration.

The light B incident on the upper substrate 43 of the liquid crystal display device from an external natural or artificial light source is reflected by the reflective electrode 49 and arranged by an electric field of the reflective electrode and the common electrode 33. After passing through the liquid crystal 56, the amount of light B passing through the liquid crystal is adjusted according to the arrangement of the liquid crystal 56 to implement an image.

On the contrary, when operating in a transmission mode, the light source uses the light A of the backlight 41 positioned below the lower substrate 53. Light emitted from the backlight 41 is incident on the liquid crystal 56 through the transparent electrode 51, and the liquid crystal arranged by the electric field of the transparent electrode 51 and the common electrode 33 of the transmission part. By 56, the image is controlled by adjusting the amount of light incident from the lower backlight 41.

3 is an enlarged plan view showing a part of an array substrate for a liquid crystal display device, and as shown, the array substrate for a reflective transmissive liquid crystal display device includes a gate wiring 25 and a data wiring 27 formed to cross each other; A thin film transistor T formed at the intersection of the pixel electrode 19 and the gate wiring 25 and including a gate electrode 61 to which a scan signal is applied, and a source electrode 63 and a drain electrode 65. Is formed.

In this case, the pixel electrode 19 is a transflective electrode composed of a transmissive portion A and a reflective portion C. First, a transparent electrode 19a is formed on the pixel region P to contact the drain electrode 65 through a first drain contact hole 67, and a transmission hole A is formed on the transparent electrode 19a. The formed reflective electrode 19b is formed.

The transparent electrode 19a contacts the drain electrode 65 through the first drain contact hole 67 formed on the drain electrode 65, and the reflective electrode 19b contacts the second drain contact hole 71. Is formed in contact with the drain electrode 65 through

4 is a schematic cross-sectional view taken along the lines II-II and III-III of FIG. 3, respectively.

With reference to FIG. 4 looks at the manufacturing process of the reflective transparent portion formed by the first method described above. (II-II is a sectional view of a pixel electrode and a thin film transistor, and III-III is a sectional view of a data wiring and a pixel area.)

First, a gate wiring (25 in FIG. 1) and a gate electrode 61 are patterned on the substrate 59, and silicon nitride (SiN _X ) and silicon dioxide (SiO ₂ ) are disposed on the gate electrode 61 and the gate wiring. The gate insulating layer 60 is formed by depositing an inorganic insulating material such as an organic insulating material such as acrylic or benzocyclobutene (BCB).

An island-type active layer 62 is formed on the upper gate insulating layer 60 of the gate electrode 61, and the source electrode 63 and the drain electrode spaced apart from each other by a predetermined distance from each other. 65) is formed.

The source electrode 63 is formed to be connected to the data line 27. In this case, the data line is formed to cross the gate line (25 of FIG. 1) with the gate insulating layer 60 interposed therebetween. The above-described insulating material is deposited on the substrate 59 on which the source electrode 63 and the like are formed to form and pattern the passivation layer 69 to form a first drain contact hole 67 on the drain electrode.

Depositing and patterning a transparent conductive material such as indium-tin oxide on the entire surface of the substrate 59 on which the first drain contact hole 67 is formed, and contacting the drain electrode 65 through the first drain contact hole. A transparent pixel electrode 19a is formed on the pixel region (see P in FIG. 1).

Next, the above-described insulating material is deposited on the pixel electrode 19a to form and pattern the passivation layer 69. The passivation layer 62 and the transparent electrode layer 19a and the upper portion of the drain electrode 65 are then patterned. The protective layer 69 is etched to form the second drain electrode contact hole 71.

Next, an opaque conductive metal having excellent reflection characteristics, such as aluminum (Al), is deposited and patterned to form a reflective electrode 19b including a transmission hole (A in FIG. 1) on the pixel region.

In this case, the reflective electrode 19b is formed in contact with the drain electrode 65 through the second drain contact hole 71 on the drain electrode 65.

At this time, the pixel electrode composed of the transparent electrode 19a and the reflective electrode 19b causes distortion of the electric field when voltage is applied by d, which is a position difference between the reflective electrode 19b and the transparent electrode 19a, so that the upper portion of the pixel electrode There is a disadvantage in reducing the driving efficiency of the liquid crystal located in.

Accordingly, an object of the present invention is to propose a liquid crystal display device having no electric field distortion and a simple process in order to solve the above problems.

According to another aspect of the present invention, there is provided an array substrate for a liquid crystal display device, the method including: providing a substrate; Forming a gate wiring and a gate electrode on the substrate; Forming a gate insulating layer on an entire surface of the substrate on which the gate electrode is formed; Forming an active layer on the gate insulating layer on the gate electrode; Forming a data wiring on the substrate on which the active layer is formed, the data wiring defining a pixel region by crossing the source electrode, the drain electrode and the gate wiring; Forming a first passivation layer by depositing an insulating material on an entire surface of the substrate on which the source and drain electrodes are formed; Forming a reflecting plate including a transmission hole on a first passivation layer on the pixel region; Depositing an insulating material on an entire surface of the substrate on which the reflector is formed to form a second protective layer, and simultaneously forming a drain contact hole by simultaneously etching the first protective layer and the second protective layer on the drain electrode; Forming a pixel electrode on the second protective layer where the drain contact hole is formed, the pixel electrode being a transparent conductive metal contacting the drain electrode through the drain contact hole.

The conductive metal is one selected from the group of conductive metals such as aluminum, molybdenum and tungsten.

The insulating layer and the protective layer are characterized in that the silicon oxide (SiO ₂ ) or silicon nitride (SiN _x ).

The transparent conductive metal is an array substrate which is indium tin oxide or indium zinc oxide.

The surface of the reflector is characterized in that it has a curved concavo-convex shape.

Hereinafter, a first embodiment and a second embodiment according to the present invention will be described with reference to the accompanying drawings.

Example 1

Unlike the related art, the first embodiment of the present invention has a structure in which a reflection plate having reflection characteristics is used without using a reflection electrode in the reflection portion.

5 is a plan view showing a part of an array substrate for a liquid crystal display device according to a first embodiment of the present invention.

As shown, the array substrate for a liquid crystal display device is largely composed of a gate wiring 111 and a data wiring 113, a pixel P, and a thin film transistor T. As shown in FIG.

The pixel P defined by the intersection of the gate wiring 111 and the data wiring 113 includes a transmission part D and a reflection part E.

The thin film transistor T includes a gate electrode 119 protruding in one direction from the gate wiring 111, and a source electrode 121 and a drain electrode 123 spaced apart from each other by a predetermined distance from an upper portion of the gate electrode 111. .

In this case, the reflecting portion E of the pixel region P is composed of anti-reflective yarns (117 of FIG. 6) having the transmission holes 115 formed thereon, and a reflecting plate having the transmission holes 115 formed thereon (see FIG. 6). A transparent electrode is formed on the front surface of the pixel on the upper portion 117 to form the pixel electrode 129.

A manufacturing process of the array substrate having such a configuration will be described with reference to FIG.

6 is a cross-sectional view taken along the line VI-VI and VIII-V of FIG. 5.

First, aluminum (Al), molybdenum (Mo), tungsten (W), and other conductive alloys, which are conductive metals, are deposited and patterned on the substrate 118 to form a gate wiring (see 111 in FIG. 5) and one direction in the gate wiring. Protruding gate electrode 119 is formed.

Next, an insulating material such as silicon oxide (SiO ₂ ) and silicon nitride (SiN _x ) is deposited on the entire surface of the substrate 118 on which the gate electrode 119 is formed, and subsequently, amorphous silicon (a-Si) and A doped amorphous silicon is deposited to form a gate insulating layer 120 and a semiconductor layer (amorphous silicon + impurity amorphous silicon).

Next, the semiconductor layer is patterned to form an active layer 125 in an island shape on the gate electrode 119.

Next, a conductive metal such as molybdenum (Mo) or tungsten (W) is deposited and patterned on the entire surface of the substrate 118 on which the active layer 125 is formed, and the gate wiring (111 of FIG. 5) and the gate insulation are patterned. The data line 113 is intersected with the layer 120 interposed therebetween, protruding in one direction from the data line, and overlapping one side of the active layer 125 with a predetermined interval therebetween. A drain electrode 123 spaced apart from the other side of the active layer 125 is formed.

Next, the first insulating layer 128 is formed by depositing the above-described insulating material on the substrate 118 on which the source electrode 121 and the drain electrode 123 are formed.

Next, a reflective plate 117 including a transmission hole is formed on the first passivation layer 128 of the pixel region (P of FIG. 5).

Next, an insulating material as described above is deposited on the entire surface of the substrate 118 on which the reflective plate 117 is formed to form the second protective layer 131.

Next, the second protective layer 131 is patterned to simultaneously etch the first protective layer 128 and the second protective layer 131 on the drain electrode 123 to form the drain contact hole 127. Form.

Next, a transparent conductive metal such as indium tin oxide (ITO) is deposited and patterned on the entire surface of the substrate 118 on which the drain contact hole 127 is formed, and the drain electrode is formed through the drain contact hole 127. A transparent electrode 129 connected to 123 and overlapping with the reflective plate 117 on the second passivation layer 131 in plan view is formed.

Accordingly, the pixel electrode is formed in a single layer by forming a transparent electrode 129 having a predetermined surface and overlapping with the reflecting plate 117 having the transmissive hole 115 in planar manner. The distortion of the electric field due to the step (d) of the 19b) and the transparent electrode (19a of FIG. 4) does not occur. The liquid crystal display device is completed by bonding the array substrate and the upper substrate on which the transparent electrode is formed, and injecting the liquid crystal between the bonded substrates.

Second Embodiment

The second embodiment relates to a structure in which the reflecting portion is further increased in forming the reflecting portion at the same time as forming the transmitting portion on the array substrate for a reflective transmissive liquid crystal display device according to the present invention.

FIG. 7 is a cross-sectional view taken along the line VI-VI and VI-VII of FIG. 5. FIG.

Until the source electrode and the drain electrode of FIG. 6 are formed, the same process will be omitted.

As illustrated, the first passivation layer 128 is formed by depositing an insulating material on the entire surface of the substrate 118 on which the source electrode 121 and the drain electrode 123 are formed.

Next, a reflective plate 117a including a transmission hole 115 is formed on the first passivation layer 128 of the pixel area P of FIG. 5.

At this time, the surface of the reflecting plate 117a is in the form of curved irregularities.

A second protective layer 131 is formed to planarize the surface of the reflecting plate 117a by depositing a transparent insulating material such as benzocyclobutene (BCB) or acrylic on the entire surface of the substrate 118 on which the reflecting plate 117a is formed. . Here, the second protective layer 131 serves to prevent the liquid crystal layer from being affected by the shape of the curved reflective plate 117a.

Next, the second protective layer 131 is patterned to form a drain contact hole 127 by etching some of the first protective layer 128 and the second protective layer 131 on the drain electrode 123. do,

Next, a transparent conductive metal such as indium tin-oxide is deposited and patterned on the second passivation layer 131 to contact the drain electrode 123 through the drain contact hole 127. ).

As described above, by forming the curved reflector plate 117a, a liquid crystal display device having excellent reflection characteristics can be obtained.

Accordingly, in the liquid crystal display according to the present invention, in forming a pixel having a transmissive part and a reflecting part, a transparent electrode contacting the drain electrode is formed on the reflective plate having the transmissive hole so that the pixel electrode itself is formed as a single layer. The distortion of the electric field due to the difference between the reflective electrode and the transparent electrode does not occur.

In addition, the surface of the reflector is formed in a curved concave-convex shape, there is an effect that can be produced a transmission reflection type liquid crystal display device excellent in reflection characteristics.

Claims (5)

Providing a substrate; Forming a gate wiring and a gate electrode on the substrate; Forming a gate insulating layer on an entire surface of the substrate on which the gate electrode is formed; Forming an active layer on the gate insulating layer on the gate electrode; Forming a data wiring on the substrate on which the active layer is formed, the data wiring defining a pixel region by crossing the source electrode, the drain electrode and the gate wiring; Forming a first passivation layer by depositing an insulating material on an entire surface of the substrate on which the source and drain electrodes are formed; Forming a reflecting plate including a transmission hole on a first passivation layer on the pixel region; Depositing an insulating material on an entire surface of the substrate on which the reflector is formed to form a second protective layer, and simultaneously forming a drain contact hole by simultaneously etching the first protective layer and the second protective layer on the drain electrode; Forming a pixel electrode of a transparent conductive metal contacting the drain electrode through the drain contact hole on the second protective layer where the drain contact hole is formed; Array substrate manufacturing method for a semi-reflective liquid crystal display device comprising a. The method of claim 1, The conductive metal is an array substrate manufacturing method selected from the group of conductive metals, such as aluminum, molybdenum, tungsten. The method of claim 1, The insulating layer and the protective layer is a silicon oxide (SiO ₂ ) or silicon nitride (SiN _x ) manufacturing method of the array substrate. The method of claim 1, The transparent conductive metal is indium tin oxide or indium zinc oxide manufacturing method of the array substrate. The method of claim 1, The surface of the reflective plate has a curved concave-convex shape manufacturing method.

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