KR20090131596A - Liquide crystal display device - Google Patents

Abstract

PURPOSE: A liquid crystal display device is provided to obtain sufficient storage capacity and improve an aperture ratio, thereby improving screen display quality and minimizing power consumed in a light source. CONSTITUTION: The first substrate comprises a plurality of pixels and a border area among a plurality of pixels. A TFT(Thin Film Transistor)(105) is formed in a region where a gate line(104) and a data line(103) within each pixel are crossed. A pixel electrode(107) is formed within each pixel one by one and is connected to the drain electrode of the TFT. Storage lines(106a,106b) are overlapped with a part of an edge region of the pixel electrode to form a storage capacitor.

Description

Liquid crystal display {LIQUIDE CRYSTAL DISPLAY DEVICE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device in which a sufficient storage capacitor is secured and an aperture ratio is improved, thereby improving display quality and minimizing power consumed by a light source.

BACKGROUND ART In general, liquid crystal display devices have tended to be gradually widened due to their light weight, thinness, and low power consumption. Accordingly, the liquid crystal display device is widely used as a means for displaying a screen in portable computers, mobile phones, office automation equipment and the like.

In general, a liquid crystal display device displays a desired image on a screen by adjusting the amount of light transmitted according to image signals applied to a plurality of control switching elements arranged in a matrix.

Such a liquid crystal display device includes a liquid crystal panel having a color filter substrate as an upper substrate and a thin film transistor array substrate as a lower substrate facing each other and a liquid crystal layer formed between the two substrates, and supplying scan signals and image information to the liquid crystal panel. It is configured to include a drive unit for operating.

A conventional liquid crystal display device having such a configuration will be described below with reference to the accompanying drawings.

As shown in FIG. 1, a conventional liquid crystal display device includes a liquid crystal panel including a first substrate 1, which is a thin film transistor array substrate, and a second substrate (not shown), which is a color filter substrate, and the first substrate. A liquid crystal layer (not shown) is formed between (1) and the second substrate.

A gate line 4 and a data line 3 are formed on the first substrate 1 so as to cross each other vertically and horizontally to define a plurality of pixels, and the gate line 4 and the data line 3 of each pixel are provided. The thin film transistor 5 is provided in the region where) cross each other.

The thin film transistor 5 is formed on a gate electrode 5a formed on the first substrate 1, a gate insulating film (not shown) formed on the gate electrode 5a, and a gate insulating film (not shown). And a source layer 5d and a drain electrode 5e formed on the semiconductor layer, and a protective layer (not shown) is formed on the source electrode 5d and the drain electrode 5e. do.

The gate electrode 5a of the thin film transistor 5 is connected to the gate line 4, the source electrode 5d is connected to the data line 3, and the drain electrode 5e is connected to the pixel electrode 7.

A storage line 6 is formed on the first substrate 1 to overlap a portion of the pixel electrode 7 to form a storage capacitor Cst. The storage line 6 is formed of a pixel electrode ( The pixel region (1) is formed so as to connect the first region 6a and the second region 6b and the first region 6a and the second region 6b, which overlap each of the left and right edges of the pixel 7, respectively. It consists of the 3rd area | region 6c which overlaps with the center area | region of 7).

In addition, a color filter layer including a color filter (not shown) corresponding to a pixel defined on the first substrate 1 is formed on the second substrate (not shown), and the gate formed on the first substrate 1 is formed. A black matrix (not shown) is formed in a region corresponding to the line 4, the data line 3, and the thin film transistor 5, and a common electrode (not shown) is formed on the color filter and the black matrix.

A light source (not shown) is provided below the liquid crystal panel having such a configuration to supply light to the liquid crystal panel.

Recently, researches to increase the aperture ratio of pixels have been actively conducted due to consumer's expectation of high resolution, and the large overlap area of the pixel electrode 7 and the storage line 6 forming the storage capacitor Cst decreases the aperture ratio. However, in order to secure sufficient storage capacitor Cst required for driving the liquid crystal display, it is impossible to reduce the overlap area between the pixel electrode 7 and the storage line 6.

Accordingly, an expectation for a liquid crystal display device having a structure capable of securing a sufficient storage capacitor Cst required for driving the liquid crystal display device and increasing the aperture ratio is increasing.

In addition, the power consumed in driving the liquid crystal display device consumes a large amount of power consumed to drive the light source for supplying light to the liquid crystal panel. Efforts are being made to reduce it. As mentioned above, if a liquid crystal display device having a high aperture ratio is designed, the amount of light supplied to the liquid crystal panel can be reduced, thereby reducing the power required for driving the light source.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a liquid crystal display device having a sufficient storage capacitor and at the same time improving the aperture ratio, thereby improving display quality and minimizing power consumed by a light source. .

According to an exemplary embodiment of the present invention, a liquid crystal display device includes: a first substrate in which a plurality of pixels and a boundary region between the plurality of pixels are defined; A plurality of data lines formed in a first direction on the first substrate and positioned in a boundary region between the plurality of pixels; A gate line formed on the first substrate in a second direction, the gate line positioned to cross a portion of the pixel; A thin film transistor formed in an area where the gate line and the data line intersect each pixel; A pixel electrode formed in each pixel and connected to the drain electrode of the thin film transistor; A storage line overlapping a portion of an edge region of the pixel electrode to form a storage capacitor; It is configured to include.

In the liquid crystal display according to the preferred embodiment of the present invention having the above configuration, the gate line is formed to cross the inside of the pixel and overlaps the pixel electrode, and the region of the gate line overlapping the pixel electrode is formed by the black matrix. Since the storage line is formed to overlap the upper and lower edges including the left and right edge regions of the pixel electrode, sufficient storage capacitors required for driving the liquid crystal display are secured.

In the liquid crystal display according to the preferred embodiment of the present invention, the gate line is formed to cross the inside of the pixel to overlap the pixel electrode, and the region of the gate line overlapping the pixel electrode is black. It does not overlap with the matrix, and the storage line is formed to overlap the upper and lower edges, including the left and right edge regions of the pixel electrode, thereby improving the aperture ratio. Since the aperture ratio is improved, the luminance of the screen displayed by the conventional liquid crystal display device can be achieved even though the power required for driving the light source is reduced.

As described above, the liquid crystal display device according to the preferred embodiment of the present invention can achieve a high aperture ratio and secure sufficient storage capacitors required for driving the liquid crystal display device, thereby minimizing the power required for driving the light source. Can improve the screen display quality.

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

As shown in FIG. 2, a liquid crystal display according to an exemplary embodiment of the present invention includes: a first substrate 101 in which a plurality of pixels and a boundary region between the plurality of pixels are defined; A plurality of data lines 103 formed on the first substrate 101 in a first direction and positioned in a boundary area between the plurality of pixels; A gate line 104 formed in the second direction on the first substrate 101 and positioned to cross a portion of the pixel; A thin film transistor 105 formed in an area where the gate line 104 and the data line 103 intersect each pixel; A pixel electrode 107 formed in each pixel and connected to the drain electrode 105e of the thin film transistor 105; And storage lines 106a and 106b overlapping a portion of an edge region of the pixel electrode 107 to form storage capacitors Cst1 and Cst2. It is configured to include.

Each component of the liquid crystal display according to the preferred embodiment of the present invention having such a configuration will be described in detail as follows.

2 and 3, a liquid crystal display according to an exemplary embodiment of the present invention includes a liquid crystal panel including a first substrate 101, which is a thin film transistor array substrate, and a second substrate 102, which is a color filter substrate. The liquid crystal layer 108 is formed between the first substrate 101 and the second substrate 102.

2, some pixels and a boundary region between the plurality of pixels are defined on the first substrate 101.

In addition, gate lines 104 and data lines 103 are formed on the first substrate 101 so as to cross each other, and the gate lines 104 and the data lines 103 are formed in the first and second directions, respectively. It is formed to cross and overlaps the central region of the pixel electrode 107, and the data line 103 is formed in the boundary region between the plurality of pixels.

The first direction and the second direction are directions in which the gate line 104 and the data line 103 may cross each other. In describing the liquid crystal display according to the exemplary embodiment of the present invention, the first direction is a horizontal direction. And the second direction is a longitudinal direction and the first direction and the second direction are perpendicular to each other, but the present invention is not limited thereto, and the first direction and the second direction do not depart from the gist of the present invention. Various examples are possible within the scope.

2, the gate line 104 is formed to traverse the inner central region of the pixel in a horizontal direction. However, the present invention is not limited thereto, and the gate line 104 is a summary of the present invention. Various examples are possible such that they are formed to be biased toward one side rather than the center region of the pixel within a range not to deviate.

Referring to FIG. 2, a thin film transistor 105 is formed in an area where the gate line 104 and the data line 103 of each pixel of the first substrate 101 cross each other to form a gate line 104 and a data line ( 103).

The thin film transistor 105 includes a gate electrode 105a formed on the first substrate 101, a gate insulating film 105b formed on the gate electrode 105a, and a semiconductor formed on the gate insulating film 105b. A layer 105c, a source electrode 105d and a drain electrode 105e formed on the semiconductor layer 105c, and a protective layer 111 on the source electrode 105d and the drain electrode 105e. Is formed.

2 and 3, one pixel electrode 107 is formed in each pixel on the first substrate 101, and the pixel electrode 107 is connected to the drain electrode 105e of the thin film transistor 105. do.

The pixel electrode 107 formed in each pixel is formed to overlap all or part of a region of the gate line 104 located inside the pixel.

In FIG. 2, the pixel electrode 107 is formed to overlap a part of a region located inside the pixel among the gate lines 104, but the present invention is not limited thereto. Various examples are possible within the range not departing from the gist of the present invention, such that the line 104 is formed to overlap the entire region located inside the pixel electrode 107.

Referring to FIG. 2, storage lines 106a and 106b are formed to overlap with a portion of an edge region of the pixel electrode 107 to form storage capacitors Cst1 and Cst2.

The storage lines 106a and 106b include a first storage line 106a formed in an upper region and a second storage line 106b formed in a lower region based on the gate line 104 in the pixel.

The first storage line 106a overlaps with an edge of an area of the pixel electrode 107 positioned above the gate line 104 in the pixel to form a first storage capacitor Cst1, and a second storage line. The line 106b overlaps an edge of a region located below the gate line 104 in the pixel of the pixel electrode 107 to form a third storage capacitor Cst2.

Referring to FIG. 3, a color filter layer formed of a color filter 109 corresponding to each pixel defined on the first substrate 101 is formed on the second substrate 102, and formed on the pixel electrode 107. The black matrix 110 is formed in the non-corresponding region, and the common electrode 112 is formed on the color filter 109 and the black matrix 110.

The black matrix 110 is formed to overlap the data line 103 and the thin film transistor 105, and partially overlaps the gate line 104. That is, the black matrix 110 is formed such that a region where the gate line 104 overlaps with the pixel electrode 107 is opened, and a region where the gate line 104 does not overlap with the pixel electrode 107 is formed. It is formed to be covered.

In FIG. 3, the black matrix 110 is formed to overlap the entire area of the gate line 104 located inside the pixel. However, the present invention is not limited thereto, and the black matrix 110 may include a gate. Various examples are possible within the scope of the present invention, such as being formed to overlap only a part of the region located inside the pixel, that is, the region not adjacent to the thin film transistor 105.

Although not shown in detail, a backlight assembly (not shown) is provided below the liquid crystal panel to supply light to the liquid crystal panel.

A light source (not shown) of the backlight assembly may be any one of a cold cathode fluorescent lamp (CCFL) and an external electrode fluorescent lamp (EEFL) light emitting diode (LED). The light source may include an optical sheet (not shown) such as a diffusion sheet, a prism sheet, and a protective sheet that converts the light emitted from the light source and proceeds in the direction of the liquid crystal panel.

In the liquid crystal display according to the exemplary embodiment of the present invention having the configuration as described above, the gate line 104 is formed to cross the inside of the pixel to overlap the pixel electrode 107, and among the gate lines 104, the pixel electrode. The region overlapping with the 107 is not overlapped with the black matrix 110, and the storage lines 106a and 106b are formed to overlap the upper and lower edges, including the left and right edge regions of the pixel electrode 107, thereby increasing the aperture ratio. At the same time, sufficient storage capacitors Cst1 and Cst2 can be secured, thereby improving display quality.

When the high aperture ratio is secured as described above, the luminance of the screen displayed by the conventional liquid crystal display can be achieved even if the power required for driving the light source is reduced, thereby increasing the amount of power required for driving the liquid crystal display. It can be minimized.

5 is a simulation result for proving the effects described above, and also shows a simulation result of a conventional general liquid crystal display.

5, the aperture ratio of the liquid crystal display according to the related art is 42.5 [%] and the aperture ratio of the liquid crystal display according to the preferred embodiment of the present invention is 53.2 [%]. It can be seen that the liquid crystal display device has an improvement effect of 7.32 [%] compared to the liquid crystal display device according to the prior art in terms of aperture ratio, and the transmittance of the liquid crystal display device according to the prior art is 6.04 [%] and the present invention. Since the transmittance of the liquid crystal display according to the preferred embodiment of the present invention is 7.55 [%], the liquid crystal display according to the preferred embodiment of the present invention has an improvement of 20 [%] compared to the liquid crystal display according to the prior art in terms of transmittance. It can be seen that there is an effect, and the white luminance of the liquid crystal display according to the prior art is 226.75 [cd / m ² ] and the aperture ratio of the liquid crystal display according to the preferred embodiment of the present invention is 244.67 [cd / m ² ], Saw foot Of the liquid crystal display device according to a preferred embodiment it can be seen that the effect of improving the 7.32 [%], as compared with the liquid crystal display device according to the prior art in the white luminance side.

Here, considering that light emitted from the backlight assembly (not shown) is largely lost while passing through the liquid crystal panel and the light efficiency is not high, the aperture ratio is improved by 7.32 [%] and the light transmittance is 6.04 [%]. The improvement and the white luminance improved by 7.32 [%] can be seen as a big achievement.

1 is a plan view showing a conventional general liquid crystal display device.

2 is a view showing a liquid crystal display according to a preferred embodiment of the present invention, a plan view showing only the first substrate for convenience of description.

FIG. 3 is a cross-sectional view taken along line II ′ of FIG. 2, and a cross-sectional view illustrating both a first substrate and a second substrate region corresponding thereto.

FIG. 4 is a cross-sectional view taken along the line II-II ′ of FIG. 2, and is a cross-sectional view showing both a first substrate and a second substrate region corresponding thereto.

FIG. 5 is simulation data for proving the effect in the liquid crystal display of FIG. 3; FIG.

** Description of the symbols for the main parts of the drawings **

101: first substrate 102: second substrate

103: data line 104: gate line

105: thin film transistor

106a: first storage line 106b: second storage line

107: pixel electrode 108: liquid crystal layer

109: color filter 110: black matrix

111: protective layer 112: common electrode

Claims (6)

A first substrate on which a plurality of pixels and a boundary region between the plurality of pixels are defined; A plurality of data lines formed in a first direction on the first substrate and positioned in a boundary region between the plurality of pixels; A gate line formed on the first substrate in a second direction, the gate line positioned to cross a portion of the pixel; A thin film transistor formed in an area where the gate line and the data line intersect each pixel; A pixel electrode formed in each pixel and connected to the drain electrode of the thin film transistor; And A storage line overlapping a portion of an edge region of the pixel electrode to form a storage capacitor; Liquid crystal display device comprising a. The liquid crystal display device according to claim 1, wherein the first direction and the second direction are directions crossing each other. The liquid crystal display of claim 1, wherein the gate line is formed such that a region located inside the pixel overlaps the pixel electrode. The liquid crystal display device according to claim 1, wherein the gate line is formed such that the remaining area of the pixel, except for a portion adjacent to the thin film transistor, overlaps the pixel electrode. The display device of claim 1, wherein the storage line comprises a first storage line formed in an upper region and a second storage line formed in a lower region based on a gate line in a pixel. And the first storage line overlaps the pixel electrode to form a first storage capacitor, and the second storage line overlaps the pixel electrode to form a second storage capacitor. The method of claim 1, further comprising a second substrate facing the first substrate, the second substrate is formed with a black matrix overlapping the data line and the thin film transistor, And wherein the black matrix has an open area in which a gate line overlaps the pixel electrode.

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