KR101128464B1 - Liquid crystal display panel and method of fabricating the same - Google Patents

Abstract

The present invention relates to a color filter substrate and a method of manufacturing the same that can improve the yield.

The present invention provides a black matrix for partitioning a liquid crystal cell region on a substrate; And a plurality of color filters formed in a cell region partitioned by the black matrix, wherein the plurality of color filters includes a predetermined binder for determining a thickness of the plurality of color filters, The thickness of the color filter is adjusted to reduce the step between the plurality of color filters.

Description

Liquid crystal display panel and its manufacturing method {LIQUID CRYSTAL DISPLAY PANEL AND METHOD OF FABRICATING THE SAME}

1 is a cross-sectional view partially showing a conventional liquid crystal display device.

2 is a cross-sectional view showing a color filter substrate having R, G, and B color filters formed with different thicknesses.

3A and 3B are cross-sectional views for explaining the flow of the ball spacer by the stepped color filter.

Figure 4 is a view for explaining the Milky Way defect due to the step of the R, G, B color filters.

5 is a cross-sectional view partially illustrating a liquid crystal display device according to an exemplary embodiment of the present invention.

6 is a cross-sectional view partially illustrating a color filter substrate according to an exemplary embodiment of the present invention.

FIG. 7 is a view showing E region shown in FIG. 6 in detail;

8 is a diagram for explaining a threshold value of a step between a plurality of color filters of the present invention;

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

2, 102: upper substrate 4, 104: black matrix

6, 106: color filter 8, 108: upper alignment layer

9, 109: gate electrode 16, 116: pixel electrode

18,118: common electrode 32, 132: lower substrate

38, 138: lower alignment layer 40, 140: source electrode

47, 147: drain electrodes 52, 152: liquid crystal

154: binder

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a color filter substrate capable of improving yield and a method of manufacturing the same.

In general, a liquid crystal display (LCD) displays an image by adjusting the light transmittance of the liquid crystal according to a video signal. To this end, the LCD includes a liquid crystal display panel in which liquid crystal cells are arranged in a matrix, and a driving circuit for driving the liquid crystal display panel.

1 is a cross-sectional view partially illustrating a conventional liquid crystal display device.

Referring to FIG. 1, the LCD includes a black matrix 4, R, G, and B color filters 6, a common electrode 18, and an upper alignment layer 8 that are sequentially formed on the upper substrate 2. The upper array substrate (or color filter substrate: hereinafter referred to as "color filter substrate"), the thin film transistor (Thin Film Transistor: hereinafter referred to as "TFT") formed on the lower substrate 32, and the pixel electrode ( 16) and a lower array substrate (or TFT substrate: hereafter referred to as " TFT substrate ") composed of a lower alignment film 38, and a liquid crystal 52 injected into an inner space between the color filter substrate and the TFT substrate.

In the color filter substrate, the black matrix 4 is formed on the upper substrate 2 in correspondence with the TFT region of the lower array substrate and the region of the gate lines and data lines, not shown, and R, G, B color filters. A cell region in which (6) is to be formed is prepared. The black matrix 4 prevents light leakage and absorbs external light to increase contrast. R, G, and B color filters 6 are formed over the cell region separated by the black matrix 4 and the black matrix 4. The R, G, and B color filters 6 are formed for each of R, G, and B to selectively transmit R, G, and B colors by selectively transmitting light having a specific wavelength. The common electrode 18 is supplied with a common voltage for controlling the movement of the liquid crystal 52.

In a TFT substrate, a TFT overlaps the gate electrode 9 formed on the lower substrate 32 together with the gate line, and the semiconductor layers 14 and 42 overlapping the gate electrode 9 and the gate insulating film 44 therebetween. ) And source / drain electrodes 40 and 47 formed together with data lines (not shown) with semiconductor layers 14 and 42 interposed therebetween. This TFT supplies a pixel signal from the data line to the pixel electrode 16 in response to a scan signal from the gate line. The pixel electrode 16 is formed of a transparent conductive material having high light transmittance and is in contact with the drain electrode 47 of the TFT through the contact hole 23 formed on the passivation layer 50. The upper and lower alignment layers 8 and 38 for liquid crystal alignment are formed by applying an alignment material such as polyimide and then performing a rubbing process.

Thereafter, a ball spacer 13 which serves to maintain a cell gap between the color filter substrate and the TFT substrate is formed on any one of the color filter substrate and the TFT substrate separately prepared as described above, and the color filter substrate and After aligning and bonding the TFT substrates, the liquid crystal 52 is injected and sealed to complete the liquid crystal display device.

The R, G, and B color filters 6 of the liquid crystal display panel determine the thicknesses of the R, G, B pigments, and the R, G, and B color filters 6, respectively, to implement a predetermined color. It includes a predetermined binder. The R, G, and B color filters 6 include different amounts of R, G, and B pigments for each of the R, G, and B color filters 6 to realize the best color coordinates for realizing color images. do. For this reason, the R, G, and B color filters 6 of the liquid crystal display panel are formed with a step by different amounts of R, G, and B pigments included therein, thereby maintaining the cell gap of the liquid crystal display panel. The ball spacer 13 is formed in the stepped space between the R, G, and B color filters 6 in some cases, and flows by an impact applied from the outside.

3A and 3B are cross-sectional views for explaining the flow of the ball spacer by the stepped color filter.

Referring to FIG. 3A, when an impact is applied in the A direction from the outside to the ball spacer 13 formed in the stepped space between the R, G, and B color filters 6, the ball spacer 13 is in the B direction. Will move. In addition, when the ball spacer 13 is moved in the B direction, the ball spacer 13 is formed by the G color filter 6 formed with a relatively larger thickness than the R color filter 6 as shown in FIG. 3B. The force applied from the direction is moved back to the D direction. Accordingly, the ball spacer 6 formed in the stepped space between the R, G, and B color filters 6 flows from the B direction to the D direction and again from the D direction to the B direction by an impact applied from the outside. do.

The flow of the ball spacer 6 interferes with the light transmittance of the liquid crystal 52 to generate light leakage, and the light leakage causes a defect in generating bright spots in the liquid crystal display panel.

In particular, the bright spots generated by the flow of the ball space 6 are different from the bright spots caused by process errors or foreign matters in one pixel, and thus the pattern of bright spots is generated in a pattern as shown in FIG. 4. .

The bright spots generated by the flow of the ball space 6 have a shape that looks like stars twinkling in the night sky when the liquid crystal display panel is driven in full black. It is called a galaxy defect that is different from a defect. Such galaxy defects are caused by the steps of the R, G, and B color filters 6 and are known to occur mainly at the edges of the pixels. It is more likely to occur when the step is large.

When bright spots occur due to the failure of the Milky Way, the liquid crystal display panel is determined to be defective, and accordingly, a method for minimizing the failure rate of the panel due to the Milky Way is required.

Accordingly, it is an object of the present invention to provide a color filter substrate and a method of manufacturing the same that can improve yield by reducing galaxy defects.

In order to achieve the above object, a liquid crystal display panel according to an embodiment of the present invention includes a thin film transistor array substrate formed with a thin film transistor, signal lines and a pixel electrode; And a color filter array substrate having a black matrix partitioning a liquid crystal cell region on a top substrate facing the thin film transistor array substrate and a plurality of color filters formed in a cell region partitioned by the black matrix. The color filter of includes a predetermined binder for determining the thickness of the plurality of color filters, and the step of reducing the step between the plurality of color filters by adjusting the thickness of the plurality of color filters by the amount of the binder added.

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A method of manufacturing a liquid crystal display panel according to an exemplary embodiment of the present invention includes forming a thin film transistor array substrate including a thin film transistor, signal lines, and a pixel electrode; Forming a color filter array substrate including a black matrix partitioning a liquid crystal cell region on a top substrate facing the thin film transistor array substrate and a plurality of color filters formed in a cell region partitioned by the black matrix; Bonding the thin film transistor array substrate and the color filter array substrate to each other; and forming the color filter array substrate may reduce a step of a plurality of color filters to be formed in a cell region partitioned by the black matrix. Adjusting an amount of a predetermined binder to determine thicknesses of the plurality of color filters; And forming the plurality of color filters in which the amount of the binder added is controlled in the cell region.

Hereinafter, exemplary embodiments of the present invention will be described with reference to FIGS. 5 to 8.

5 is a cross-sectional view partially illustrating a liquid crystal display device according to an exemplary embodiment of the present invention, and FIG. 6 is a cross-sectional view partially illustrating a color filter substrate according to an exemplary embodiment of the present invention.

5 and 6, the liquid crystal display device includes a black matrix 104, an R, G, and B color filters 106, a common electrode 118, and an upper alignment layer 108 sequentially formed on the upper substrate 102. ) An upper array substrate (or a color filter substrate: hereinafter referred to as a "color filter substrate"), a thin film transistor (Thin Film Transistor: hereinafter referred to as "TFT") formed on the lower substrate 132, The lower array substrate (or TFT substrate: referred to as a "TFT substrate") composed of the pixel electrode 116 and the lower alignment layer 138, and the liquid crystal 152 injected into the internal space between the color filter substrate and the TFT substrate Equipped.

In the color filter substrate, the black matrix 104 is formed on the upper substrate 102 to correspond to the TFT region of the lower array substrate and the gate lines and data lines regions not shown, and R, G, and B color filters Prepare a cell region in which 106 is to be formed. The black matrix 104 prevents light leakage and absorbs external light to increase contrast. R, G, and B color filters 106 are formed over the cell region and black matrix 104 separated by the black matrix 104. The R, G, and B color filters 106 are formed for each of R, G, and B to selectively transmit light having a specific wavelength, thereby implementing R, G, and B colors. The common electrode 118 is supplied with a common voltage for controlling the movement of the liquid crystal 152.

In a TFT substrate, a TFT overlaps a gate electrode 109 formed on a lower substrate 132 with a gate line, and a semiconductor layer 114 and 142 overlapping a gate electrode 109 and a gate insulating film 144 therebetween. ) And source / drain electrodes 140 and 147 formed with data lines (not shown) with semiconductor layers 114 and 142 interposed therebetween. This TFT supplies the pixel signal from the data line to the pixel electrode 116 in response to the scan signal from the gate line. The pixel electrode 116 is formed of a transparent conductive material having high light transmittance and is in contact with the drain electrode 147 of the TFT through the contact hole 123 formed on the passivation layer 150. The upper and lower alignment layers 108 and 138 for liquid crystal alignment are formed by applying an alignment material such as polyimide and then performing a rubbing process.

Thereafter, a ball spacer 113 which serves to maintain a cell gap between the color filter substrate and the TFT substrate is formed on any one of the color filter substrate and the TFT substrate separately prepared as described above, and the color filter substrate and After aligning and bonding the TFT substrates, the liquid crystal 152 is injected and sealed to complete the liquid crystal display device.

The R, G, and B color filters 106 of the liquid crystal display panel respectively determine predetermined thicknesses of the R, G, and B pigments, and the R, G, and B color filters 106, which implement a predetermined color. It includes a binder of. The R, G, and B color filters 106 include different amounts of R, G, and B pigments for each of the R, G, and B color filters 106 in order to realize the best color coordinates for implementing color images. do.

According to the present invention, the amount of R, G, and B pigments for implementing the color coordinates of the R, G, and B color filters 106 is maintained at an appropriate level for each of the R, G, and B color filters 106, and the color image is implemented. By reducing the amount of the binder 154 of the R, G, B color filter 106 irrelevant reduces the step between the R, G, B color filter 106. That is, the color filter substrate of the present invention is a binder (a) in the color filter 106 formed of a relatively low thickness of the R, G, B color filter 106 in order to reduce the step of the R, G, B color filter 106 R, G, and B color filters 106 to which 154 is added are provided. At this time, the binder 154 added to reduce the step difference between the R, G, and B color filters 106 is an element that determines only the volume of the R, G, and B color filters 106, and the R, G, B color filters ( It does not affect the color coordinate of 106).

5 and 6, the thickness of the R color filter 106 is expressed as the lowest, but this is only one example, depending on the pigment used to form each of the R, G, B color filter 106 Therefore, the thickness of the G color filter 106 may be the lowest. In addition, the binder 154, which is added to reduce the level difference, forms the R, G, and B color filters 106 mixed with the dye. The reason why the amount of the binder 154 added to increase the thickness of the R color filter 106 is expressed as shown in FIGS. 5 and 6 to explain the binder 154 added through the drawings.

As described above, the color filter substrate of the present invention uses the amount of the binder 154 that is irrelevant to the color coordinates of the R, G, and B color filters 106 among the components of the R, G, and B color filters 106 formed therein. By adjusting the thickness by adjusting, the step difference between the R, G, and B color filters 106 is reduced. Accordingly, the ball spacer 113 is formed in a region where the step difference between each of the R, G, and B color filters 106 is reduced and does not flow due to the impact applied from the outside, thereby reducing the defect of the milky way.

FIG. 7 is a view showing the region E shown in FIG. 6 in detail, and FIG. 8 is an experimental measurement diagram for explaining a threshold value of steps between the R, G, and B color filters 106 capable of preventing the Milky Way defect.

Model A of FIG. 8 is a general model without adjusting the amount of binder 154 added to the R, G, and B color filters 106, and model B and C are the binders 154 of the R, G, and B color filters 106. ) Is a model according to an embodiment of the present invention to adjust the amount of addition.

7 and 8, the step (d) threshold between the R, G, and B color filters 106, which may prevent the Milky Way defect, may be applied to the largest thickness among the R, G, and B color filters 106. It is about 10% of the thickness of the color filter 106. At this time, the more preferable step of the R, G, B color filter 106 which can prevent a galaxy defect is 0.150 micrometer or less.

8, the amount of the B color filter 106 coated with the largest thickness is 1.675 μm and the amount of the R color filter 106 applied with the smallest thickness is 1.441. The range of the step d between the B color filter 106 and the R color filter 106 was 0.234 占 퐉 as 占 퐉. At this time, the range of the step between the R, G, B color filter 106 is shown in the range of 14% of the B color filter 106 applied to the largest thickness of the R, G, B color filter 106, the Milky Way The level of failure was medium.

On the contrary, in the case of the B model, the amount of the B color filter 106 applied with the largest thickness is 1.594 μm and the amount of the R color filter 106 applied with the smallest thickness is 1.436 μm, so that the B color filter 106 is used. And the range of the step d between the R color filter 106 is 0.158 mu m. At this time, the range of the step between the R, G, B color filters 106 was shown to be the range of 9.9% of the B color filter 106 applied with the largest thickness among the R, G, B color filters 106, The level of defects is a medium level, indicating that the number of defects in the Milky Way is much reduced.

In addition, in the case of the C model, the amount of the G color filter 106 applied with the largest thickness is 1.725 μm and the amount of the R color filter 106 applied with the smallest thickness is 1.641 μm, so that the B color filter 106 is used. And the range of the step d between the G color filter 106 is 0.084 mu m. At this time, the range of the step between the R, G, B color filters 106 was found to be in the range of 4.8% of the B color filter 106 applied with the largest thickness among the R, G, B color filters 106 and the Milky Way It can be seen that the defect is hardly shown.

As described above, the color filter substrate of the present invention adjusts the thickness of the binder 154 that is not related to the color coordinates of the R, G, and B color filters 106 among the components of the R, G, and B color filters 106. By adjusting the R, G, B color filter 106 can be formed by reducing the step difference between the R, G, B color filter 106. Accordingly, the ball spacer 113 is formed in a region where the step difference between each of the R, G, and B color filters 106 is reduced and does not flow due to the impact applied from the outside, thereby reducing the defect of the milky way.

As described above, the color filter substrate and the method of manufacturing the same according to the embodiment of the present invention by adjusting the thickness of the binder constituting the R, G, B color filter to control the step between the R, G, B color filter Can be reduced. Accordingly, the ball spacer is formed in a region where the step difference between each of the R, G, B color filters is reduced and does not flow due to the impact applied from the outside, thereby reducing the defect of the Milky Way.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification, but should be defined by the claims.

Claims (20)

delete delete delete delete delete delete delete delete delete delete A thin film transistor array substrate having thin film transistors, signal lines, and pixel electrodes formed thereon; A color filter array substrate having a black matrix partitioning a liquid crystal cell region on a top substrate facing the thin film transistor array substrate and a plurality of color filters formed in a cell region partitioned by the black matrix; The plurality of color filters includes a predetermined binder that determines the thickness of the plurality of color filters, and adjusts the thickness of the plurality of color filters by the amount of the binder to reduce the step between the plurality of color filters, A liquid crystal display panel comprising adding the binder to a color filter having the lowest thickness among the color filters. The method of claim 11, And the step between the plurality of color filters is maintained within 10% of the thickness of the color filter having the largest thickness among the plurality of color filters. The method of claim 11, And a step difference between the plurality of color filters is 0.150 μm or less. The method of claim 11, Each of the plurality of color filters further comprises R, G, and B pigments for implementing a predetermined color. The method of claim 11, Wherein the plurality of color filters include R, G, and B color filters. Forming a thin film transistor array substrate comprising thin film transistors, signal lines and pixel electrodes; Forming a color filter array substrate including a black matrix partitioning a liquid crystal cell region on a top substrate facing the thin film transistor array substrate and a plurality of color filters formed in a cell region partitioned by the black matrix; Bonding the thin film transistor array substrate and the color filter array substrate to each other; Forming the color filter array substrate, In order to reduce the level of the plurality of color filters to be formed in the cell region partitioned by the black matrix, the amount of the predetermined binder that determines the thickness of the plurality of color filters is adjusted, and the lowest thickness of the plurality of color filters is adjusted. Adding the binder to a color filter to be formed; And forming the plurality of color filters in which the amount of the binder is added in the cell region. The method of claim 16, And the plurality of color filters are formed such that a step between the plurality of color filters is within a range of 10% of a thickness of the color filter having the largest thickness among the plurality of color filters. The method of claim 16, And the plurality of color filters are formed such that a step between the plurality of color filters is 0.150 µm or less. The method of claim 16, And each of the plurality of color filters further comprises R, G, and B pigments for implementing a predetermined color. The method of claim 16, The plurality of color filters comprises a R, G, B color filter manufacturing method of the liquid crystal display panel.

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