KR20040029561A - Liquid Crystal Display Device - Google Patents

Abstract

PURPOSE: An LCD element is provided to have the second column spacers in partition wall structure on an upper substrate, in order to prevent a liquid crystal from drooping by inferior gravity, thereby unifying a luminous type of a screen. CONSTITUTION: An upper substrate(40) and a lower substrate(50) are opposite to each other at certain intervals. A liquid crystal layer is filled between the upper substrate(40) and the lower substrate(50). The first column spacers(61) are fixed to one region of the upper substrate(40) in order to maintain cell gaps between the upper substrate(40) and the lower substrate(50). The second column spacers(62) are fixed to the upper substrate(40) in partition wall type. The upper substrate(40) comprises as follows. A black matrix layer(41) cuts off light except for a pixel region. An RGB color filter layer expresses colors. An overcoat layer protects and planarizes the color filter layer. A common electrode is applied with a voltage to implement an image on the overcoat layer.

Description

Liquid 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 suitable for maintaining a cell gap and at the same time preventing stains generated as the liquid crystal sags down the panel.

As the information society develops, the demand for display devices is gradually increasing in various forms, and in recent years, liquid crystal display devices (LCDs), plasma display panels (PDPs), electro luminescent displays (ELDs), and VFDs (Vacuum) Various flat panel display devices such as fluorescent display have been studied, and some are already used as display devices in various devices.

Among them, LCD is the most used as a substitute for CRT (Cathode Ray Tube) for mobile image display device because of the excellent image quality, light weight, thinness, and low power consumption. In addition to mobile type such as notebook computer monitor, BACKGROUND ART Various developments have been made in televisions and computer monitors for receiving and displaying broadcast signals.

Although various technical advances have been made in order for such a liquid crystal display device to serve as a screen display device in various fields, the task of improving the quality of an image as a screen display device is often arranged with the above characteristics and advantages.

Therefore, in order to use a liquid crystal display device in various parts as a general screen display device, it is a matter of how high quality images such as high definition, high brightness, and large area can be realized while maintaining the characteristics of light weight, thinness, and low power consumption. have.

Such a liquid crystal display device may be classified into a liquid crystal panel displaying an image and a driving unit for applying a driving signal to the liquid crystal panel.

The liquid crystal panel includes a bottom plate in which a plurality of pixel regions are arranged in a matrix form, one thin film transistor and one pixel electrode are arranged for each pixel, and a color filter and a common electrode for displaying color. It consists of a top plate and a liquid crystal layer filled between the top plate and the bottom plate.

On both sides of the upper and lower plates, polarizing plates for linearly polarizing visible light (natural light) are attached.

The liquid crystal display device having the above-described configuration needs to accurately maintain the interval of the liquid crystal cell in order to implement high contrast ratio, wide viewing angle characteristic, and to prevent color change. have.

In particular, in a liquid crystal display device using a specific mode such as a twisted nematic mode, a high contrast ratio may not be obtained and display stains may be generated on the screen unless the gap between the liquid crystal cells is accurately maintained in accordance with optical characteristics.

As described above, maintaining the correct gap of the liquid crystal cell in the liquid crystal display device is an essential element in producing a high quality liquid crystal display device.

As described above, spacers are used to maintain a constant gap between the liquid crystal cells, that is, the thickness of the liquid crystal layer. A type of spacer includes a ball spacer scattered on a substrate and a column spacer attached to the substrate. column spacer).

In this case, the ball spacer is formed by dispersing small particles called spacers formed of plastic balls or elastomeric plastic particles through a spreader on a substrate (ie, a lower substrate) on which a switching element is formed. It is formed by spreading, and a column spacer is formed by attaching a hard material such as photosensitive organic resin to the top plate.

Hereinafter, a liquid crystal display device according to the related art will be described with reference to the accompanying drawings.

1 is a plan view of a liquid crystal display device according to the prior art, and FIGS. 2A and 2B are cross-sectional views of a structure of the liquid crystal display device according to the prior art.

As shown in FIGS. 1 and 2A, a conventional liquid crystal display device includes an upper substrate 10 on which a color filter layer is formed, a lower substrate 20 on which a thin film transistor is formed, and an upper and lower substrates 10 and 20. The liquid crystal layer 30 is filled with a column spacer 31 fixed at regular intervals between the upper substrate 10 and the lower substrate 20 to maintain a cell gap between the upper and lower substrates 10 and 20. do.

Here, the lower substrate 20 (TFT array substrate) includes a plurality of gate lines (not shown) arranged in one direction at regular intervals, and a plurality of data arranged at regular intervals in a direction perpendicular to the gate lines. A line (not shown), a plurality of pixel electrodes 21 formed in a matrix form in each pixel region defined by crossing each of the gate lines and the data lines, and switched by a signal of the gate line to A plurality of thin film transistors (TFTs) 22 for transmitting a signal to each pixel electrode 21 is formed.

In addition, the upper substrate 10 (color filter substrate) includes a black matrix layer 11 for blocking light in portions other than the pixel area 25 and an R, G, B color filter layer for expressing color color ( 12, an overcoat layer 13, and a common electrode 14 to which a voltage is applied to implement an image are formed on the color filter layer 12.

1 illustrates a view in which the upper substrate 10 and the lower substrate 20 are bonded together, and more specifically, the plurality of pixel regions 25 are arranged in a matrix form on the lower substrate 20. The black matrix layer 11 is formed on the upper substrate 10 corresponding to the region except the pixel region 25 of the lower substrate 20.

As described above, in the conventional liquid crystal display device, as shown in FIG. 2A, column spacers 31 are disposed to maintain a constant cell gap when the upper and lower substrates 10 and 20 are bonded to each other. A plurality of patterns 31 are fixed to one region of the upper substrate 10 at regular intervals.

The column spacer 31 is formed of a photosensitive organic resin.

Instead of the column spacer 31, as shown in FIG. 2B, the ball spacer 32 may be randomly scattered on the lower substrate 20 to maintain the cell gap.

Reference numerals 15 and 24 are alignment films, and 23 are protective films.

The liquid crystal display device configured as described above has a problem that the liquid crystal is drooped under the panel under the influence of gravity as the medium / large size becomes large, whereby the amount of the liquid crystal is concentrated in the lower panel and the cell gap in the lower portion increases.

In addition, as the liquid crystal sags to the lower part of the panel, the liquid crystal driving becomes poor, cell gap irregularity occurs at the lower part, and the light emission form of the screen becomes uneven.

The present invention has been made to solve the above problems, and in particular, it is an object of the present invention to provide a liquid crystal display device capable of maintaining a cell gap and preventing liquid crystals from falling down under the panel.

1 is a plan view of a liquid crystal display device according to the prior art

2A and 2B are structural cross-sectional views of a liquid crystal display device according to the related art.

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

4 is a cross-sectional view of a structure of a liquid crystal display device according to an embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

40: upper substrate 41: black matrix layer

42: color filter layer 43: overcoat layer

44 common electrode 45, 58 alignment film

50: lower substrate 51: thin film transistor

52: gate electrode 53: gate insulating film

54 active layer 55a source electrode

55b: drain electrode 56: pixel electrode

57: protective film 60: liquid crystal layer

61: first column spacer 62: second column spacer

The liquid crystal display device of the present invention for achieving the above object is an upper substrate on which a color filter layer is formed, a lower substrate on which a thin film transistor is formed, a plurality of first column spacers formed on the upper substrate, and the upper substrate And a plurality of second column spacers formed in a line shape, and a liquid crystal layer filled between the upper and lower substrates.

The first and second column spacers are formed of a photosensitive organic resin.

The first column spacer has a predetermined shape and is fixedly formed in one region of the upper substrate.

The second column spacer is fixed to the upper substrate in a vertical and horizontal direction.

The lower substrate includes a plurality of gate lines arranged in one direction at predetermined intervals, a plurality of data lines arranged in a direction perpendicular to the gate lines, and respective pixel regions defined by crossing the gate lines and data lines. A plurality of pixel electrodes formed in a matrix form and a plurality of thin film transistors TFT formed at intersections of the gate lines and the data lines are formed.

The first column spacer is formed on the upper substrate corresponding to one region where the gate line or data line is formed.

The second column spacer is formed in a vertical direction and a horizontal direction on the upper substrate corresponding to the partial gate line and the data line.

As described above, the present invention is characterized by further comprising a column spacer having a partition structure in order to prevent the liquid crystal from sagging at the bottom of the panel while arranging the column spacer in a predetermined region of the upper substrate to maintain the cell gap.

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

3 is a plan view of a liquid crystal display device according to an exemplary embodiment of the present invention, and FIG. 4 is a cross-sectional view of a structure of the liquid crystal display device according to an exemplary embodiment of the present invention.

As shown in FIGS. 3 and 4, the liquid crystal display according to the exemplary embodiment of the present invention has an upper substrate 40 and a lower substrate 50 facing each other at predetermined intervals, and the upper and lower substrates 40, A plurality of first column spacers 61 fixed to one region of the upper substrate 40 to maintain a cell gap between the liquid crystal layer 60 filled between the upper substrate and the upper and lower substrates 40 and 50; And a plurality of second column spacers 62 fixed to the upper substrate 40 in a vertical and horizontal partition wall shape.

Here, the upper substrate 40 (color filter substrate) includes a black matrix layer 41 for blocking light in portions other than the pixel region 59, and R, G, and B color filter layers for expressing color colors. (42), an overcoat layer (43) for protecting and planarizing it on the color filter layer (42), and a common electrode (44) to which a voltage is applied to implement an image on the overcoat layer (43).

The overcoat layer 43 may not be formed.

The lower substrate 50 (TFT array substrate) includes a plurality of gate lines (not shown) arranged in one direction at a predetermined interval, and a plurality of data lines arranged at regular intervals in a direction perpendicular to the gate lines. And a plurality of pixel electrodes 56 formed in a matrix form in each pixel region 59 defined by crossing the gate lines and the data lines, and switched by the signals of the gate lines. A plurality of thin film transistors (TFTs) 51 transferred to the pixel electrodes 56 and a passivation layer 57 formed on an entire surface of the lower substrate 50 including the pixel electrodes 56 are provided.

In this case, the thin film transistor 51 includes a gate electrode 52 protruding on one side of the gate line having one direction, a gate insulating film 53 formed on the entire surface of the lower substrate 50, and a gate insulating film on the upper side of the gate electrode 52. The active layer 54 formed on the 53, the source electrode 55a protruding from the data line so as to overlap the upper portion of the gate electrode 52, and the upper portion of the gate electrode 52 so as to overlap the other side of the gate electrode 52. The drain electrode 55b is formed to be separated from the source electrode 55a by a predetermined interval.

The protective layer 57 is formed to protect the active layer 54 from external moisture or foreign matter, and may be formed of any one of acrylic, polyimide, benzocyclobutene (BCB), oxide film, and nitride film. Form.

The alignment layers 45 and 58 made of polyimide or a photo-alignment material are formed on the common electrode 44 of the upper substrate 40 and the protective layer 57 of the lower substrate 50, respectively.

Here, the alignment layer made of polyimide is determined by mechanical rubbing, and the photoreactive material made of polyvinylcinnamate based material or polysiloxane based material is oriented by irradiation with light such as ultraviolet rays. This is determined.

At this time, the orientation direction is determined by the irradiation direction of the light or the property of the irradiated light, that is, the polarization direction.

The first and second column spacers 61 and 62 are formed of a photosensitive organic resin, and the first column spacer 61 is one of the upper substrates 40 corresponding to one region where a gate line or a data line is formed. The second column spacer 62 is formed to have a predetermined pattern on the region, and the second column spacer 62 is formed to form a partition wall in the vertical and horizontal directions with respect to the upper substrate 40 corresponding to the gate lines and the data lines of the plurality of gate lines and the data lines. It is.

In addition to the role of maintaining the cell gap with the first column spacer 61, the second column spacers 62 patterned in the vertical and horizontal directions may have a liquid crystal filled between the upper and lower substrates 40 and 50. It also acts as a barrier to prevent sagging under the liquid crystal panel.

In general, a large liquid crystal display device has a larger amount of liquid crystal than a small liquid crystal display device, and a large amount of liquid crystal sags downward due to poor gravity. Therefore, when the second column spacer 62 having a barrier rib structure is configured, As a result, the liquid crystal is drooped under the liquid crystal panel so that cell gap unevenness can be prevented from occurring on the lower portion of the screen.

For example, when manufacturing a liquid crystal display device of about 40 ", the distance between the second column spacers 62 may be approximately the size (for example, 10") of the medium model.

As described above, the column spacer may be applied to a liquid crystal display device using a liquid crystal dropping method. In the liquid crystal dropping method, a liquid crystal is dropped on one of the upper and lower substrates, and the upper and lower substrates are bonded in a vacuum. To encapsulate the liquid crystal.

That is, the liquid crystal dropping method does not inject the liquid crystal by the pressure difference between the inside and the outside of the unit liquid crystal panel, but directly drops the liquid crystal onto the large-area glass substrate and drops the liquid crystal dropped by the bonding pressure of the substrate. It distributes uniformly over and forms a liquid crystal layer.

The manufacturing method of the liquid crystal display device by the liquid crystal dropping method is as follows.

First, the column spacer is attached to the lower substrate (TFT substrate) or the upper substrate (color filter substrate), and then an alignment material is applied on the lower substrate (TFT substrate) and the upper substrate (color filter substrate), and the liquid crystal molecules are uniform. After the alignment process is performed to have one orientation, the lower substrate and the upper substrate are cleaned, respectively.

At this time, the column spacer is formed in a portion corresponding to the gate line or the data line of the lower substrate, as in the present invention is formed by patterning in a predetermined shape in one region, perpendicular to the portion corresponding to some gate lines and data lines, It may also be patterned to form a horizontal partition wall.

In the IPS mode, column spacers are formed at portions corresponding to the common lines.

Thereafter, the cleaned upper substrate is loaded on a seal dispensing device and the seal material is applied to the periphery of each panel region.

In this case, the seal material may use a photocurable resin or a thermosetting resin and do not need to make a liquid crystal injection hole.

In addition, the lower substrate is loaded into a liquid crystal dispensing device to drop liquid crystal onto an active array region of each panel.

At this time, the cleaned lower substrate or the upper substrate is loaded on the Ag dispensing equipment to form Ag dots in the common voltage supply line on the lower substrate.

In addition, silver dot formation may be omitted, as in IPS (In Plane Switching) mode.

Subsequently, the lower substrate and the upper substrate are loaded into a vacuum adapter chamber to bond the lower substrate and the upper substrate so that the dropped liquid crystal is uniformly filled in each liquid crystal panel, and the seal material is cured to form a liquid crystal disc.

Subsequently, S / B (Scribe / Break) process is performed, and the S / B process is a scribe that forms a cutting line on the surface of the substrate with a pen or wheel made of diamond, which is harder than glass. The liquid crystal original plate is cut into a panel (liquid crystal panel) of several cell units.

Thereafter, after performing a grinding process of polishing the cut surface of the liquid crystal panel, each panel is subjected to A / P (Auto / Probe) inspection to complete the liquid crystal cell process.

The present invention is not limited to the above embodiments, and includes various forms that can be easily derived by those skilled in the art from the above embodiments.

The liquid crystal display of the present invention as described above has the following effects.

By providing the second column spacer of the partition structure on the upper substrate, it is possible to prevent the phenomenon that the liquid crystal is drooped to the lower part of the panel due to the gravity failure, so that staining occurs in the lower part of the screen.

Accordingly, the light emission form of the screen can be made uniform.

Claims (7)

An upper substrate on which a color filter layer is formed, A lower substrate on which a thin film transistor is formed, A plurality of first column spacers formed on the upper substrate; A plurality of second column spacers formed in a line shape on the upper substrate; And a liquid crystal layer filled between the upper and lower substrates. The method of claim 1, The first and second column spacers are formed of a photosensitive organic resin. The method of claim 1, And the first column spacer has a predetermined shape and is fixedly formed in one region of the upper substrate. The method of claim 1, And the second column spacer is fixed to the upper substrate in the vertical and horizontal directions. The method of claim 1, The lower substrate has a plurality of gate lines arranged in one direction at a predetermined interval, A plurality of data lines arranged in a direction perpendicular to the gate lines; A plurality of pixel electrodes formed in a matrix form in each pixel region defined by crossing each of the gate lines and the data lines; And a plurality of thin film transistors (TFTs) formed at intersections of the gate lines and the data lines. The method according to claim 1 or 5, And the first column spacer is formed on the upper substrate corresponding to one region where the gate line or data line is formed. The method according to claim 1 or 5, And the second column spacer is formed in a vertical direction and a horizontal direction on the upper substrate corresponding to the partial gate line and the data line.