KR20090060053A - Liquide crystal display device - Google Patents

Abstract

A liquid crystal display device is provided to secure the enough storage capacitor by making a pixel electrode overlapped with a common voltage line and shield line. A liquid crystal display device comprises the first substrate, a gate line, a data line, a common voltage line, a shield line, a common electrode and a pixel electrode. The gate line and data line are formed on the substrate so as to cross each other and define a plurality of pixels. The common voltage line is formed so as to be parallel to the gate line and cross the data line. The shield line is branched from the common voltage line and is formed parallel to the data line at one side of the data line. The common electrode is connected with the shield line through contact hole.

Description

Liquid crystal display {LIQUIDE CRYSTAL DISPLAY DEVICE}

The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device having an improved aperture ratio in the transverse electric field mode.

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 portable computer such as a notebook PC, office automation equipment, audio / video 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 form.

The liquid crystal display includes a liquid crystal panel in which a color filter substrate as an upper substrate and a thin film transistor array substrate as a lower substrate are opposed to each other, and a liquid crystal layer is filled therebetween, and the scanning is performed on the liquid crystal panel. And a liquid crystal panel driver for supplying signals and image information to operate the liquid crystal panel.

The liquid crystal display having such a configuration is classified into various modes according to the arrangement of the liquid crystal and the arrangement of the electrodes applying the electric field to the liquid crystal. The mainly used modes are twisted namatic (TN) mode and IPS (in plain). switching mode).

The liquid crystal display of the TN mode is arranged so that the initial orientation of the liquid crystal is twisted in a spiral while going from the bottom to the top, and electrodes are formed on the upper and lower substrates to apply a vertical electric field to the liquid crystal. In the liquid crystal display of the IPS mode, the initial alignment of the liquid crystal is arranged horizontally on the substrate, and electrodes are formed on the lower substrate to apply a horizontal electric field to the liquid crystal.

Among the liquid crystal display devices of the various modes described above, the TN mode liquid crystal display device has a big disadvantage that the viewing angle is narrow. Recently, the use of the IPS mode liquid crystal display device having the wide viewing angle has been increased. There is a trend.

Hereinafter, a liquid crystal display of a conventional general IPS mode will be described with reference to FIG. 1.

As shown in FIG. 1, a general 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 includes the first substrate 1. The gate line 2 and the data line 3 which cross each other in the longitudinal direction and define a plurality of pixels are formed, and the thin film transistor is formed in the region where the gate line 2 and the data line 3 of each pixel cross each other. 10 is provided.

In each pixel of the first substrate 1, a pixel electrode 7 including a plurality of pixel partial electrodes 7a arranged in a direction parallel to the data line 3 is formed.

In addition, a common voltage line 14 disposed in parallel with the gate line 2 is formed on the first substrate 1, and is branched from the common voltage line 14 to be adjacent to the data line 3. A shield line 4 is formed at both edges of the pixel, and is connected to the shield line 4 through the contact hole 5 to form a plurality of common partial electrodes 6a intersecting with the pixel electrode 7. The configured common electrode 6 is also formed.

Referring to FIG. 1, each pixel has a left-right symmetrical structure so as not to affect the driving of the pixel by matching the size of parasitic capacitors formed between the pixel electrode 7 and the data line 3 on the left and right sides of the pixel. It is formed to be.

That is, each pixel has a symmetrical structure except for the region where the thin film transistor 10 is formed, as shown in FIG. 1. In particular, when driving the dot inversion, the parasitic capacitors between the pixel electrode 7 and the data line 3 formed on the left and right sides of the pixel cancel each other to have no influence on the driving.

As described above, for the symmetrical structure of the pixels, the number of the common partial electrodes 6a and the pixel partial electrodes 7a in each pixel are designed to be different from each other. Specifically, the common partial electrodes 6a are the pixel partial electrodes. Have one more than (7a).

Referring to FIG. 2, in the process of designing the conventional liquid crystal display device as described above, as the size of the liquid crystal display device and the size of the pixel become larger, the space between the pixel partial electrode 7a and the common partial electrode 6a is increased. When the size is gradually increased, the size of the pixel partial electrode 7a and the common partial electrode 6a are increased one by one, that is, when the response speed of the liquid crystal is reached (A, B, C in FIG. 2). In addition, the aperture ratio of the pixel is drastically reduced. That is, in the design process as described above, a pixel having a size at which the space between the pixel partial electrode 7a and the common partial electrode 6a is located at the threshold at which the response speed of the liquid crystal becomes slow is at a pixel having a size not positioned at the threshold. In comparison, a problem occurs that the aperture ratio is significantly lower.

As such, when the aperture ratio decreases rapidly, the display quality of the liquid crystal display device is degraded.

Accordingly, the present invention is to solve the problems of the prior art as described above, an object of the present invention is to form the same number of the common partial electrode and the pixel partial electrode provided in each pixel and to form each pixel asymmetrically, but the data The present invention provides a liquid crystal display device capable of ensuring a sufficient aperture ratio without adversely affecting the driving of liquid crystals by providing a sufficient area where a shield line overlapping a predetermined area with a pixel partial electrode closest to a line is exposed.

According to an exemplary embodiment of the present invention, a liquid crystal display device includes: a first substrate; Gate lines and data lines formed on the first substrate to cross each other to define a plurality of pixels; A common voltage line parallel to the gate line and intersecting the data line; A shield line branched from the common voltage line and formed in parallel with the data line on one side of the data line; A common electrode connected to the shield line through a contact hole, the common electrode including a plurality of common partial electrodes formed to be parallel to a data line in each pixel; A pixel electrode formed in the pixel to cross the common partial electrode, the pixel electrode including the same number of pixel partial electrodes as the number of the common partial electrodes; It is configured to include.

In the liquid crystal display according to the preferred embodiment of the present invention having the above-described configuration, the pixel partial electrode is formed to have the same number of common partial electrodes and pixel partial electrodes provided in each pixel and is closest to the data line in each pixel. By maximizing the exposed area of the overlapping shield line, the size of the space between the pixel partial electrode and the common partial electrode gradually increases as the size of the pixel increases in the pixel design process during manufacturing of the liquid crystal display. When the lower limit reaches a slower point, in the conventional pixel structure, only one additional pixel partial electrode is formed and an area where a shield line overlapping the pixel partial electrode closest to the data line is provided is provided. Thus, the response speed of the liquid crystal becomes slow. Liquid crystal display in certain models with specific pixels of size corresponding to the threshold There is an advantage that the problem that the opening ratio of the device is suddenly reduced does not occur.

In the liquid crystal display according to the preferred embodiment of the present invention having the configuration described above, a sufficient storage capacitor can be secured by overlapping the pixel electrode with the common voltage line and the shield line.

In addition, since a sufficient storage capacitor is provided as described above, since the area of the overlap region of the pixel electrode and the common voltage line for forming the storage capacitor can be minimized, the aperture ratio is improved.

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. 3, a liquid crystal display according to a preferred embodiment of the present invention includes a first substrate 101; A gate line 102 and a data line 103 formed on the first substrate 101 to cross each other to define a plurality of pixels; A common voltage line 114 formed to be parallel to the gate line 102 and cross the data line 103; A shield line (104) branched from the common voltage line (114) and formed on one side of the data line (103) in parallel with the data line (103); A common electrode 106 connected to the shield line 104 and a contact hole 105 and having a plurality of common partial electrodes 106a formed in parallel to the data line 103 in each pixel; A pixel electrode 107 formed in each pixel to cross the common partial electrode 106a and having the same number of pixel partial electrodes 107a as the number of the common partial electrodes 106a; 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.

The liquid crystal display according to the present invention includes a liquid crystal panel including a first substrate 101 as a thin film transistor array substrate and a second substrate (not shown) as a color filter substrate, wherein the first substrate 101 and the second substrate are provided. A liquid crystal layer (not shown) is formed therebetween.

Referring to FIG. 3, a gate line 102 and a data line 103 are formed on the first substrate 101 to cross each other in a longitudinal direction, and define a plurality of pixels. Each pixel includes a gate line 102 and a gate line 102. The thin film transistor 110 is formed in an area where the data lines 103 cross each other.

The thin film transistor 110 may include a gate electrode 110a formed on the first substrate 101, a gate insulating film (not shown) formed on the gate electrode 110a, and the gate electrode 110a formed on the gate insulating film. A semiconductor layer (not shown) formed to overlap and a source electrode (110b) and a drain electrode (110c) formed on the semiconductor layer, and a protective layer (not shown) on the source electrode (110a) and drain electrode (110c) This is further formed.

The gate electrode 110a of the thin film transistor 110 is connected to the gate line 102, the source electrode 110b is connected to the data line 103, and the drain electrode 110c is connected through the contact hole 108. It is connected to the pixel electrode 107.

Referring to FIG. 3, a common voltage line 114 is formed on the first substrate 101 to be parallel to the gate line 102 and intersect the data line 103.

The common voltage line 114 receives a common voltage from a liquid crystal panel driver (not shown) and applies the common voltage to the common electrode 106.

In addition, a shield line 104 is formed on the first substrate 101 to be branched from the common voltage line 114 to be parallel to the data line 103 on one side of the data line 103.

That is, the shield line 104 is disposed at both edges of each pixel, thereby preventing the phenomenon in which the driving of the liquid crystal in the pixel is distorted by the data signal transmitted through the data line 103.

Referring to FIG. 3, a common electrode 106 including a plurality of common partial electrodes 106a formed in each pixel in parallel with the data line 103 is formed on each of the first substrates 101.

The common electrode 106 is connected to the common voltage line 114 by being connected to the shield line 104 through the contact hole 105 to receive a common voltage from the common voltage line 114.

In FIG. 3, the contact hole 105 is provided at one of two regions where the shield line 104 and the common electrode 114 overlap each other, and an area other than the common partial line 106a is formed in the common electrode 106. Although the present invention is not limited thereto, the contact hole 105 is provided in both regions where the shield line 104 and the common electrode 106 overlap or the common electrode ( Various examples are possible in the number and position of the common part line 106a provided only in a portion overlapping with the shield line 104 in the range 106.

Each pixel on the first substrate 101 is provided with a pixel electrode 107 composed of a pixel partial electrode 107a alternately formed with the common partial electrode 106a. The pixel portion constituting the pixel electrode 107 is provided. The electrodes 107a are formed to have the same number as the number of the common partial electrodes 106a.

That is, referring to FIG. 3, the number of the pixel partial electrode 107a constituting the pixel electrode 107 and the common partial electrode 106a constituting the common electrode 106 are the same with respect to the center of each pixel. The structure is asymmetrical left and right.

In the case of implementing the asymmetrical structure as described above, the size of parasitic capacitor generated between the data line 103 and the pixel electrode 107 in each of the left and right pixels is different, the liquid crystal display device according to the preferred embodiment of the present invention. In the pixel structure of, the pixel partial electrodes 107a disposed on the rightmost side of the pixel partial electrodes 107a constituting the pixel electrodes 107 formed in each pixel are spaced apart from each other at a sufficient distance from the data line 103. The formation of the capacitor is minimized, and the leftmost pixel partial electrode 107a is not disposed at a sufficient distance from the data line 103, but the shield line in which the leftmost pixel partial electrode 107a overlaps a predetermined area ( The parasitic generated between the data line 103 and the pixel electrode 107 by being disposed so that the 104 is not overlapped with the pixel portion electrode 107a by at least 2 μm. Formation of the capacitor is minimized and thus does not affect the driving of the liquid crystal.

Accordingly, the liquid crystal display according to the preferred embodiment of the present invention can realize the asymmetric structure of the pixels as described above, and at the same time, the left and right of the parasitic capacitor formed between the data line 103 and the pixel electrode 107 in each pixel. There is an effect that does not cause problems due to asymmetry.

3, since the pixel electrode 107 overlaps with the common voltage line 114 and the shield line 104, sufficient storage capacitor Cst is provided, so that the pixel electrode 107 and the common voltage line ( Since the overlapped area 114 can be minimized, the aperture ratio of each pixel is improved.

3 and the description of the present invention, the pixel partial electrode 107a disposed at the rightmost side of the pixel partial electrode 107a constituting the pixel electrode 107 formed in each pixel is spaced apart from the data line 103 at a sufficient distance. Although the pixel partial electrode 107a spaced apart and disposed at the leftmost side is disposed adjacent to the data line 103 as an example, the present invention is not limited thereto, and the pixel electrode 107 formed in each pixel is not limited thereto. The pixel partial electrode 107a disposed on the leftmost side of the pixel partial electrode 107a is spaced apart from the data line 103 by a sufficient distance, and the pixel partial electrode 107a disposed on the rightmost side is connected to the data line 103. Various examples are possible without departing from the gist of the present invention, such as being disposed adjacently. Of course, when the pixel partial electrode 107a disposed on the rightmost side of the pixel partial electrode 107a constituting the pixel electrode 107 in each pixel is disposed adjacent to the data line 103, the pixel portion disposed on the rightmost side. The shield electrode 104 having a predetermined area overlapping the electrode 107a should be formed so as not to overlap the pixel portion electrode 107a by at least 2 μm.

The liquid crystal display according to the preferred embodiment of the present invention having the configuration as described above is common with the pixel partial electrode as the size of the liquid crystal display and the size of the pixel gradually increase during the pixel design process in manufacturing the liquid crystal display. When the size of the space between the partial electrodes is gradually increased and the response speed of the liquid crystal is slowed to reach the limit which cannot be increased any more, the pixel partial electrode is formed in the pixel structure of the conventional liquid crystal display, and one more pixel partial electrode is formed at the same time. By designing a pixel structure such as a liquid crystal display according to the present invention by maximizing the area where the shield line overlapped with the pixel portion electrode closest to the data line is exposed, the pixel size is gradually increased. As the space between the pixel partial electrode and the common partial electrode increases, the response speed of the liquid crystal becomes slow. When reaching the limit which can not be increased any more, the pixel structure of the liquid crystal display according to the present invention is changed to form only one common electrode in the pixel structure of the liquid crystal display according to the present invention so as to overlap the shield line. By being used in the design process, the problem that the aperture ratio of a specific model having pixels of a size corresponding to a threshold at which the response speed of the liquid crystal becomes slow does not occur.

That is, referring to FIG. 4, the size of the space between the pixel partial electrode and the common partial electrode is gradually increased as the size of the liquid crystal display and the size of the pixel are gradually increased during the pixel design process in manufacturing the liquid crystal display. In the case where the response speed of the liquid crystal is increased to reach the limit point (A, B, C, D, E, F of FIG. 4) which can not be increased any more, the pixel structure of the liquid crystal display according to the present invention and the conventional liquid crystal display By alternately applying the pixel structure of the device, since only one of the common partial electrode or the pixel partial electrode needs to be formed in each pixel each time, the aperture ratio decreases rapidly in a specific model having a pixel size corresponding to the threshold at which the response speed of the liquid crystal becomes slow. Since this does not occur and the aperture ratio is secured, the screen quality of the liquid crystal display device is improved.

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

2 is a graph showing the relationship between pixel size and aperture ratio in the pixel design of a conventional liquid crystal display.

3 is a plan view showing a liquid crystal display device according to a preferred embodiment of the present invention.

4 is a graph showing the relationship between pixel size and aperture ratio in the pixel design of the liquid crystal display of the present invention;

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

101: first substrate

102 gate line 103 data line

104: shield line

106: common electrode 106a: common partial electrode

107: pixel electrode 107a: pixel partial electrode

110: thin film transistor

Claims (4)

A first substrate; Gate lines and data lines formed on the first substrate to cross each other to define a plurality of pixels; A common voltage line parallel to the gate line and intersecting the data line; A shield line branched from the common voltage line and formed in parallel with the data line on one side of the data line; A common electrode connected to the shield line through a contact hole, the common electrode including a plurality of common partial electrodes formed to be parallel to a data line in each pixel; A pixel electrode formed in the pixel to cross the common partial electrode, the pixel electrode including the same number of pixel partial electrodes as the number of the common partial electrodes; Liquid crystal display device comprising a. The liquid crystal display of claim 1, wherein the pixel electrode overlaps the common voltage line to form a storage capacitor. 2. The liquid crystal display device according to claim 1, wherein the pixel partial electrode closest to the data line in each pixel overlaps the shield line to form a storage capacitor. The liquid crystal display device according to claim 1, wherein an area corresponding to a left and right width of at least 2 μm is exposed in the shield electrode overlapping the pixel partial electrode closest to the data line in each pixel.

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