KR101849567B1 - Liquid crystal display device - Google Patents

Abstract

The present invention relates to a liquid crystal display device capable of preventing a reduction in uniformity between pixels due to a process error, comprising: a first substrate and a second substrate facing each other; A liquid crystal layer filled between the first substrate and the second substrate; A gate line formed on one surface of the first substrate facing the liquid crystal layer; A gate insulating film formed on the entire surface of the first substrate including the gate line; A data line formed on the gate insulating film so as to intersect the gate line so that a plurality of pixel regions are defined; A common line formed on one surface of the first substrate in parallel with the gate line; Shield lines formed on both sides of the data lines on one surface of the first substrate, the shield lines extending in the common line so as to be in parallel with the data lines; A protective film formed on the entire surface of the gate insulating film including the data lines; A pixel electrode and a common electrode alternately formed in each of the plurality of pixel regions on the protective film; And a dummy electrode formed on the protective film, the dummy electrode being connected to the common electrode and formed in parallel with the data line, the dummy electrode including a portion overlapping the shield line and another portion disposed within the pixel region do.

Description

[0001] LIQUID CRYSTAL DISPLAY DEVICE [0002]

The present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device capable of improving image quality.

In recent years, as the information age has come to a full-fledged information age, a display field for visually expressing electrical information signals has been rapidly developed. In response to this, various flat panel display devices having excellent performance of thinning, light weight, Flat Display Device) has been developed to replace CRT (Cathode Ray Tube).

Specific examples of such flat panel display devices include a liquid crystal display device (LCD), an organic light emitting display (OLED), an electrophoretic display (EPD) A plasma display panel (PDP), a field emission display (FED), an electroluminescence display (ELD), and an electro-wetting display (EWD) And the like. In general, a flat panel display panel, which realizes images, is an essential component. The flat panel display panel has a structure in which a pair of substrates are bonded together with a unique light emitting material or a layer of polarizing material therebetween. Among them, a liquid crystal display is a typical example of a flat panel display, and displays an image by adjusting the light transmittance of the liquid crystal for each pixel by using an electric field.

A general liquid crystal display device includes a liquid crystal layer filled between a lower substrate and an upper substrate facing each other, a liquid crystal layer filled between a lower substrate and an upper substrate, and a plurality of pixel regions corresponding to a plurality of pixels, And a transistor array for defining a pixel electrode and a common electrode that form an electric field, and a plurality of pixel regions, respectively, and applying a pixel voltage corresponding to each pixel to the pixel electrode.

At this time, since the liquid crystal cells of the liquid crystal layer corresponding to the outside of the plurality of pixel regions are not influenced by the electric field between the pixel electrode and the common electrode, the liquid crystal cells do not have a properly controlled direction, Is a cause of degradation in image quality.

Accordingly, the liquid crystal display device further includes a black matrix formed outside the plurality of pixel regions, so that only light due to the liquid crystal cell having a direction controlled by the electric field between the common electrode and the pixel electrode in each pixel region is emitted to the outside To be released. However, if a process error occurs in which the mask is aligned differently from the design in the black matrix formation process, a black matrix may be formed inside the pixel region. In this case, there is a problem that the electric field generated between the pixel electrode and the common electrode is affected by the conductivity of the black matrix.

On the other hand, in accordance with the demand of the user, the liquid crystal display device is becoming larger. Accordingly, the masks necessary for the patterning process for forming the transistor array, the pixel electrode, the common electrode, and the black matrix should also be prepared in a large size (size) in accordance with a large substrate.

However, if the mask is prepared in a large size, a phenomenon (hereinafter referred to as "sagging phenomenon ") occurs in which the mask is sagged down by its own weight at the time of patterning, and excessive tension is applied to the mask There is a problem that the pattern of the mask is deformed. Due to such a problem, it is common to use a method of arranging a plurality of masks in parallel and using the masks as a large mask (hereinafter referred to as a "division mask method") in a patterning process for manufacturing a large-sized liquid crystal display device.

However, when a divided mask is used, a process error occurs in aligning a plurality of divided masks, which results in a problem that the uniformity between pixels is lowered.

For example, a black matrix, which should be disposed outside the pixel region, can be formed in the pixel region while the division mask is pushed along the alignment direction. In particular, since the range of the process error differs for each divided mask, the area in which the black matrix is involved in each pixel region is different, and the luminance characteristic of each pixel can be different thereby.

That is, due to a process error occurring when the divided masks are aligned, the uniformity between pixels is reduced, and some pixels may appear darker than other pixels, and image quality is deteriorated as some pixels are recognized as spots.

Particularly, when a touch is applied to a touch panel or a liquid crystal panel attached to a liquid crystal panel for the sake of convenience of the user, the distance between the upper and lower substrates of the liquid crystal panel is changed and the position of the black matrix may slightly fluctuate have. At this time, the uniformity between pixels is further lowered, and the image quality deteriorates.

An object of the present invention is to provide a liquid crystal display device capable of compensating a positional variation of a black matrix by a division mask and an external touch, thereby improving pixel uniformity and improving image quality.

According to an aspect of the present invention, there is provided a plasma display panel comprising: a first substrate and a second substrate facing each other; A liquid crystal layer filled between the first substrate and the second substrate; A gate line formed on one surface of the first substrate facing the liquid crystal layer; A gate insulating film formed on the entire surface of the first substrate including the gate line; A data line formed on the gate insulating film so as to intersect the gate line so that a plurality of pixel regions are defined; A common line formed on one surface of the first substrate in parallel with the gate line; Shield lines formed on both sides of the data lines on one surface of the first substrate, the shield lines extending in the common line so as to be in parallel with the data lines; A protective film formed on the entire surface of the gate insulating film including the data lines; A pixel electrode and a common electrode alternately formed in each of the plurality of pixel regions on the protective film; And a dummy electrode formed on the protective film, the dummy electrode being connected to the common electrode and formed in parallel with the data line, the dummy electrode including a portion overlapping the shield line and another portion disposed within the pixel region do.

As described above, the liquid crystal display according to the present invention includes dummy electrodes formed in parallel with the data lines and partially disposed in the pixel regions. Accordingly, interference between the pixel electrode and the common electrode due to the signal of the data line and interference between the pixel electrode and the common electrode due to a process error or an external touch, It is possible to prevent the interference with the electric field, so that the luminance characteristics between the pixels can be made uniform.

1 is a plan view showing some pixels in a liquid crystal display device according to an embodiment of the present invention.
2 is a cross-sectional view taken along line I-I 'of FIG.
Figs. 3A and 3B show cases where an external touch is applied from the left and right sides in Fig.
4 shows a comparative example of a general liquid crystal display device.
5A and 5B show a case where an external touch is applied from the left and right sides in FIG.
6 shows the positions of the first to sixth pixels in the four divided mask areas and the four divided mask areas in Table 1.
FIGS. 7A to 7C are images showing a case where a touch is applied to the first to sixth pixels shown in FIG. 6 from the left and right sides in the general liquid crystal display device shown in FIG.
8A and 8B are images showing luminance characteristics of a pixel in a liquid crystal display device according to an embodiment of the present invention.

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

1 is a cross-sectional view taken along line I-I 'of FIG. 1, and FIGS. 3 (a) and 3 (b) And an external touch is applied from the right side.

1, a liquid crystal display according to an exemplary embodiment of the present invention includes a gate line GL and a data line DL, which are cross-disposed to define a plurality of pixel regions respectively corresponding to a plurality of pixels, A thin film transistor (not shown) formed in a crossing region of the gate line GL and the data line DL, a common line CL arranged in parallel to the gate line GL, A shield line SL disposed parallel to both sides of the data line DL, a pixel electrode PE and a common electrode CE arranged alternately in the pixel region, and a data line DL connected to the common electrode CE, And a dummy electrode DE including a portion overlapping the shield line SL and another portion formed in the pixel region.

A thin film transistor (not shown) includes a gate electrode connected to the gate line, a source electrode connected to the data line, and a drain electrode connected to the pixel electrode PE through the first contact hole CH1. When the thin film transistor (not shown) turns on, a pixel voltage corresponding to each pixel is applied to the pixel electrode PE.

The common line CL is connected to the common electrode CE and the dummy electrode DE through the second contact hole CH2 to apply a common voltage corresponding to all the pixels in common.

Such a liquid crystal display device displays an image by adjusting the luminance of each of a plurality of pixels by using an electric field between the pixel electrode PE and the common electrode CE in each of a plurality of pixel regions.

2, a liquid crystal display according to an exemplary embodiment of the present invention includes a first substrate Sb and a second substrate Su, a first substrate Sb A liquid crystal layer (LC) filled between the second substrate (Su) and the second substrate (Su), a gate line GL formed parallel to one side of the first substrate Sb facing the liquid crystal layer LC, A shield line SL formed so as to extend from the common line CL so as to be in parallel with the data line DL on both sides of the common line CL and the data line DL on one surface of the first substrate Sb, A gate insulating film GI formed on the entire surface of one side of the first substrate Sb including the line GL, the common line CL and the shield line SL, the gate insulating film G1 formed on the gate line GL on the gate insulating film GI, A passivation layer Passi formed on the entire surface of the gate insulating layer GI including the data lines DL and the data lines DL formed between the two shield lines SL, A pixel electrode PE and a common electrode CE alternately formed in each of a plurality of pixel regions PA on a passivation layer Passi and a common electrode CE on the passivation layer Passi, And a dummy electrode DE including a part (1) overlapping the shield line SL and another part (2) disposed in the pixel area PA.

The liquid crystal display device is formed outside a plurality of pixel regions PA on one surface of a second substrate Su facing the liquid crystal layer LC and includes a black matrix BM for blocking light leakage and a second substrate Su And a color filter (CF) formed in each of the plurality of pixel regions on one side of the pixel region and transmitting light in a wavelength region representing a predetermined color.

The shield lines SL extend from the common line CL and are formed in parallel with the data lines DL on both sides of the data line DL with the gate insulating film GI therebetween. These shield lines SL are disposed so as to interpose between the data line DL and the pixel region at the same voltage level as the common line CL so that a signal applied to the data line DL is applied to the common electrode CE And blocks the influence on the electric field between the pixel electrodes PE.

The dummy electrode DE is connected to the common electrode CE and is connected to the data line DL on both sides of the data line DL with a protective film Passi therebetween, (1)) and another portion (2) arranged in the pixel area PA. The dummy electrode DE is connected to the common line CL or the shield line SL through the second contact hole CH2. The dummy electrode DE is disposed so as to interpose between the data line DL and the pixel area PA while having the same voltage level as the common line CL, Is prevented from affecting the electric field between the common electrode CE and the pixel electrode PE.

The two adjacent electrodes of the dummy electrode DE, the pixel electrode PE and the common electrode CE formed on the passivation layer are spaced apart from each other at a predetermined interval (EI: Electrode Interval). The pixel electrode PE and the common electrode CE are formed in the same width (EW: Electrode Width).

The liquid crystal layer LC is composed of a liquid crystal cell having a predetermined initial alignment direction and the liquid crystal cell rotates in a direction corresponding to the electric field between the pixel electrode PE and the common electrode CE to selectively transmit light.

The color filters CF are respectively formed in a plurality of pixel regions on one surface of the second substrate Su and transmit light in a wavelength region corresponding to a predetermined color corresponding to each of the plurality of pixels. For example, the color filter CF may be formed of a dye or a fluorescent material that transmits light corresponding to one of red, green, and blue (RGB) colors corresponding to each pixel region.

On the other hand, a portion (1) of the dummy electrode DE is a portion covered by the black matrix BM, and another portion (2) of the dummy electrode DE is a portion not covered by the black matrix BM. That is, another portion (2) of the dummy electrode DE is a portion extending into the pixel region PA by a predetermined additional width (AW).

 Thus, in each pixel, light is not emitted from the entire surface of the pixel area PA but the remaining area (EA: Efficient Area (EA)) excluding the width AW covered by another portion , Hereinafter referred to as "effective area (EA)"). That is, the effective area EA has a smaller width than the pixel area PA by an additional width of the dummy electrode DE located on both sides of the pixel area PA.

However, the position of the black matrix BM is slightly changed due to an external touch or an alignment error of the mask during the manufacturing process, so that a part of the black matrix BM can be disposed in the pixel area PA . At this time, the black matrix BM is arranged only outside the effective area EA.

3A, even when the black matrix BM is shifted to the left side of the design and partially disposed within the pixel area PA by the force of the left side, the black matrix BM is not formed in the effective area EA . Similarly, as shown in FIG. 3B, even when the black matrix BM is disposed slightly within the pixel area PA by biasing to the right of the design due to the right side force, the black matrix BM is formed in the effective area EA, As shown in Fig.

As described above, since the black matrix BM is not disposed in the effective area EA regardless of the positional variation of the black matrix BM, the effective areas EA in which light is emitted from all the pixels become the same, The luminance characteristic can be made uniform.

On the other hand, as shown in Fig. 4, the dummy electrode DE of a general liquid crystal display device is formed only outside the pixel region EA so as to be covered by the black matrix BM. 5A, when the black matrix BM is shifted to the left side of the design and partially disposed within the pixel area PA by the force of the left side, the black matrix BM is formed in the pixel area PA, The conductive black matrix BM affects the electric field between the pixel electrode PE and the common electrode CE by the width ER of the pixel electrode PE. 5B, when the black matrix BM is shifted to the left side of the design by a force of the right side and is partially disposed within the pixel area PA, the black matrix BM is shifted to the pixel area PA The conductive black matrix BM affects the electric field between the pixel electrode PE and the common electrode CE as much as the width ER to be involved.

As a result, the electric field between the pixel electrode PE and the common electrode CE is shaken due to the influence of the black matrix BM, and the transmittance of the portion adjacent to the black matrix BM is lowered, And the image quality is deteriorated.

As described above, the liquid crystal display according to the embodiment of the present invention includes the dummy electrode DE including another portion (2) disposed in the pixel region PA, so that the position of the black matrix BM in each pixel Uniformity of the inter-pixel luminance characteristic can be improved by emitting light only in the effective area EA that maintains a constant width regardless of the variation.

Particularly, in the case of using the split mask method, a process error necessarily occurs in aligning a plurality of divided masks, and the width of another part (2) of the dummy electrode DE, that is, the additional width AW) need to be adjusted.

Table 1 below shows the process errors in the case of manufacturing the comparative example shown in FIG. 4 by the split mask method. Table 1 shows the conditions in which the dummy electrode DM is spaced apart from the pixel area PA by 4.3 μm and the gap EI between neighboring electrodes is 9.3 μm and the width EW of the electrode is 3.2 μm to 3.5 μm The results are shown in Fig. Table 2 summarizes the average and maximum values of the process errors.

Table 1 shows the first divided area M1 and the second divided area M2 adjacent to each other with the first interface S1, the second interface S2 and the third interface S3 therebetween, Adjacent to the first to third interfaces S1 to S3 in the two-divided region M2, the third divided region M3, the third divided region M3, and the fourth divided region M4, The positional error of the black matrix BM with respect to the design value after the first substrate Sb and the second substrate Su are attached together and the positional error of the black matrix BM on the left side and the right side Of the black matrix BM. 6, the X direction is the alignment direction (XL, XR) of the mask.

Referring to FIGS. 7A to 7C, it can be seen that as the black matrix BM touches the pixel region due to the left or right touch, the electric field is shaken at the edge of the pixel region, resulting in a portion darker than the other portion have.

Table 2 shows the average value and the maximum value of the results of Table 1 and the change in the distance between the black matrix BM and the neighboring electrode (pixel electrode PE).

As shown in Table 2, the positional errors in the X direction are 6.4 um and the maximum error is 11 um, and the position errors in the Y direction are 2.8 um and 6.9 um on average, respectively, by the touches on the left or right side. When moved in the X and Y directions, the maximum positional error is 10.5 μm in the X direction and 6 μm in the Y direction. It can be confirmed that the change in distance between the black matrix BM and the neighboring electrode (pixel electrode PE) is 7.15 μm on the average and 13 μm on the maximum due to the positional change of the black matrix BM.

Accordingly, the width (i.e., the additional width AW) of the other part (2) of the dummy electrode DE according to the embodiment of the present invention is smaller than the mask alignment error in the split mask process and the external touch Is determined to be 7.15 to 13 um based on the mask alignment direction (X direction) in consideration of the position variation range of the black matrix (BM) by the exposure apparatus. 1, when the shape of the data line, the pixel electrode, and the common electrode corresponding to each pixel region has a bent portion having an obtuse angle or more, the additional width AW may vary depending on the angle of the bent portion. Do.

That is, if the dummy electrode DE is extended to the pixel region with an additional width AW of 7.15 to 13 um, even if the alignment error of the divided mask and the position of the black matrix BM are changed by external touch, May be disposed only outside the valid area EA. Therefore, fluctuation of the position of the black matrix BM can prevent the effective area EA of each pixel from fluctuating, and light can be emitted in the same area in all the pixels. As a result, since the inter-pixel luminance characteristics can be made uniform, the image quality can be improved regardless of the mask alignment error of the division mask process.

8A, even if an alignment error of the mask occurs, it can be confirmed that the brightness characteristic of each pixel is uniform. As shown in Fig. 8B, when the touch is applied in the mask alignment direction under the condition of Fig. It can be confirmed that the same luminance characteristics are exhibited between the neighboring pixels.

The present invention described above is not limited to the above-described embodiment and the accompanying drawings, and various substitutions, modifications, and changes may be made without departing from the technical spirit of the present invention.

GL: gate line CL: common line
DL: Data line SL: Shield line
PE: pixel electrode CE: common electrode
DE: dummy electrode Sb: first substrate (lower substrate)
GI: gate insulating film Passi: protective film
LC: liquid crystal layer Su: second substrate (upper substrate)
BM: Black matrix CF: Color filter

Claims (7)

A first substrate and a second substrate facing each other;
A liquid crystal layer filled between the first substrate and the second substrate;
A gate line disposed on one surface of the first substrate facing the liquid crystal layer;
A gate insulating film disposed on the entire surface of the first substrate including the gate line;
A data line arranged on the gate insulating film so as to intersect the gate line so that a plurality of pixel regions are defined;
A common line disposed on one surface of the first substrate in parallel with the gate line;
Shield lines disposed on both sides of the data line on one surface of the first substrate, the shield lines being extended from the common line so as to be in parallel with the data lines;
A protective film disposed on the entire surface of the gate insulating film including the data line;
A pixel electrode and a common electrode arranged alternately in each of the plurality of pixel regions on the protective film;
A dummy electrode connected to the common electrode and arranged in parallel with the data line, the dummy electrode including a portion overlapped with the shield line and another portion disposed in the pixel region; And
And a black matrix disposed on the one surface of the second substrate facing the liquid crystal layer and outside the plurality of pixel regions to block light leakage,
Wherein a side surface of the black matrix is disposed closer to the pixel region than a side surface of the shield line overlapped with the dummy electrode,
Wherein a portion of the dummy electrode is covered by the black matrix,
Wherein when the black matrix is formed using a plurality of masks, another portion of the dummy electrodes has a width of 7.15 to 13 um with respect to an arrangement direction of the plurality of masks. The method according to claim 1,
And a color filter transmitting light in a wavelength range corresponding to each of the plurality of pixel regions and representing a predetermined color on one surface of the second substrate. delete delete delete The method according to claim 1,
Further comprising a thin film transistor disposed in a crossing region of the gate line and the data line,
And the pixel electrode is connected to a drain electrode of the thin film transistor through a first contact hole passing through the protective film. The method according to claim 6,
And the dummy electrode and the common electrode are connected to the shield line through a second contact hole passing through the protective film and the gate insulating film.

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