KR20070038608A - Rubbing device of an alignment layer for liquid crystal display device - Google Patents

Abstract

The present invention relates to an alignment film rubbing device of a liquid crystal display device, and more particularly, to an alignment film rubbing device for preventing the substrate from twisting.

A feature of the present invention is to prevent the substrate from twisting by forming a groove to allow the substrate to be seated on the stage where the substrate is positioned during the alignment film rubbing process.

Accordingly, there is an effect of solving the problem of reducing the contrast ratio due to the rubbing shaft failure caused by the distortion of the substrate.

Alignment layer rubbing device, rubbing axis, stage, liquid crystal display device

Description

Rubbing device of an alignment layer for liquid crystal display device

1 is a perspective view schematically showing a liquid crystal panel of a general liquid crystal display device;

2 is a perspective view for explaining a general alignment film rubbing process.

3 is a flowchart illustrating a process sequence of a manufacturing process of a liquid crystal panel for a liquid crystal display according to an exemplary embodiment of the present invention.

Figure 4 is a perspective view for explaining an alignment film rubbing process according to an embodiment of the present invention.

5 is a cross-sectional view schematically showing a state of a substrate seated in a groove formed on a stage.

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

111, 113: substrate 125: stage

127: rubbing cloth 129: rubbing roll

131: support 133: alignment film

The present invention relates to an alignment film rubbing device of a liquid crystal display device, and more particularly, to an alignment film rubbing device for preventing the substrate on the stage from twisting.

Cathode ray tube (CRT), one of the widely used display devices, has been mainly used for monitors such as TVs, measuring devices, information terminal devices, etc., but the miniaturization of electronic products due to the large weight and size of the CRT itself It could not respond actively to the demand for weight reduction.

In order to replace the CRT, a liquid crystal display device having advantages of small size and light weight has been actively developed, and recently, the liquid crystal display device has been developed enough to perform a role as a flat panel display device, and its demand is gradually increasing. For this reason, new technologies have been actively introduced into mounting semiconductor chips for driving LCD panels for miniaturization and weight reduction.

1 is a perspective view schematically illustrating a liquid crystal panel of a general liquid crystal display device.

As shown in the drawing, the general liquid crystal panel 10 is bonded to the array substrate 1 and the color filter substrate 3 at predetermined intervals, and on one surface of the array substrate 1 facing the color filter substrate 3. The data wiring DL and the gate wiring GL defining the pixel region 9 are perpendicularly intersected with each other, and the thin film transistor 7 is formed at the intersection of the two wirings DL and GL.

One surface of the color filter substrate 3 facing the array substrate 1 includes a grid-like black matrix 11 and a color filter 13, and includes the color filter 13 and the black matrix 11. The transparent common electrode 15 is formed on the front surface of the color filter substrate.

The liquid crystal 5 is filled between the array substrate 1 and the color filter substrate 3.

At this time, although not shown, the thin film transistor 7 includes a gate electrode, an active layer, a source and a drain electrode.

Finally, an alignment layer 23 is formed on surfaces of the array substrate 1 and the color filter substrate 3 that face each other.

The liquid crystal display device 10 is an apparatus in which an image is expressed by adjusting an amount of light passing through the liquid crystal layer 5 according to the arrangement characteristics of the liquid crystals exhibiting optical anisotropy.

The arrangement characteristic of the liquid crystal molecules has a great influence on the optical characteristics of the liquid crystal display device 10. Therefore, controlling the alignment characteristics of the liquid crystal is a very important problem. In particular, the alignment layer 23 has the greatest influence on the molecular arrangement of the liquid crystal.

The alignment layer 23 is subjected to a rubbing treatment to give a groove to the surface, this rubbing process refers to rubbing the surface of the alignment layer in a certain direction by using a rubbing cloth wound around the roller.

When the surface of the alignment layer 23 is rubbed, the surface of the alignment layer 23 is shaped to have fine grooves.

2 is a perspective view for explaining a general alignment film rubbing process.

As shown, a general alignment film rubbing device includes a stage 25 for positioning the substrates 1 and 3, a rubbing roll 29 to which a rubbing cloth 27 is attached, and a support for supporting the rubbing roll 29. It consists of 31.

When the substrates 1 and 3 on which the alignment layer 33 is formed are positioned on the stage 25, the rubbing roll 29 on which the rubbing cloth 27 is wound maintains a constant gap with the substrates 1 and 3. Will be located.

In this case, the substrates 1 and 3 are positioned on the stage 25 through rotation and alignment in accordance with the traveling direction of the rubbing roll 29.

Next, the rubbing roll 29 rotates at a high speed. At this time, the rubbing cloth 27 attached to the surface of the rubbing roll 29 contacts the alignment layer 33 formed on the substrates 1 and 3, By rubbing the surface of the alignment film 33, an alignment pattern is formed on the surface of the alignment film 33.

The alignment pattern formed on the surface of the alignment layer 33 should be uniformly formed in a large area of the substrates 1 and 3, and thus will have uniform display characteristics.

However, when the stage 25 moves, the substrates 1 and 3 positioned on the stage 25 are distorted to occur.

For this reason, the advancing direction of the said board | substrates 1 and 3 and the said rubbing roll 29 turns, and the rubbing axis of the board | substrates 1 and 3 will turn.

This means that when the two substrates are bonded together after the rubbing process of the color filter and the array substrates 1 and 3, the entire liquid crystal director in the liquid crystal cell is distorted. The distortion of the liquid crystal director has a problem in that light leakage occurs when driving the panel after the polarizer is attached, thereby reducing the contrast ratio (CR) of the liquid crystal display.

The present invention is to solve the above problems, and an object of the present invention is to prevent the substrate located on the stage from twisting during the alignment film rubbing process.

In order to achieve the object as described above, the present invention is a substrate coated with an alignment film; A stage on which the substrate is seated and a groove is formed; Located on top of the stage, comprising a rubbing roll attached to the rubbing cloth and a support for supporting the rubbing roll, the substrate provides an alignment film rubbing device, characterized in that seated in the groove formed on the stage.

The grooves formed in the stage are configured to have a side of a constant slope, the method comprising: seating a substrate coated with an alignment layer on the grooves formed on the stage; Positioning the stage on which the substrate is seated horizontally spaced apart from a rubbing roll on which a rubbing cloth is wound; Rotating the rubbing roll and advancing the stage toward the rubbing roll; It provides an alignment film rubbing process comprising the step of forming an alignment pattern on the surface of the alignment film by the rubbing cloth of the rotating rubbing roll.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

3 is a flowchart illustrating a manufacturing process of a liquid crystal panel for a general liquid crystal display according to an exemplary embodiment of the present invention according to a process sequence.

The first step st 1 is to prepare an upper substrate as a color filter substrate and a lower substrate as an array substrate, respectively.

The array substrate includes a thin film transistor including a gate electrode, a semiconductor layer, a source and a drain electrode, and a pixel electrode serving as an electrode.

A color filter layer is formed on the color filter substrate to transmit only light of a specific wavelength band at a position corresponding to the pixel electrode of the array substrate, and a black matrix is formed at a color boundary of the color filter layer to cover the non-pixel region.

In addition, a common electrode for applying a voltage to the liquid crystal layer is formed under the color filter layer and the black matrix.

The second step st 2 is a cleaning process for removing the foreign matter on the color filter and the array substrate.

The third step st 3 is to form an alignment layer on the color filter substrate and the array substrate.

The liquid crystal display device uses the electro-optical effect of the liquid crystal, and the electro-optic effect is determined by the anisotropy of the liquid crystal itself and the molecular arrangement state of the liquid crystal, and the control of the molecular arrangement of the liquid crystal is an image display in the liquid crystal display device. It will have a big impact on stabilizing dignity. Therefore, an alignment process is performed to even the initial arrangement of liquid crystal molecules.

The alignment process can be broadly divided into an alignment film printing step of forming an alignment film on a substrate, and an alignment film surface treatment step of forming polymer chains having directivity in a predetermined direction on the surface of the alignment film formed on the substrate.

The alignment film printing process is to form a polyimide (Polyimide), a polymer material mainly used as an alignment film on the entire surface of the array substrate or color filter substrate.

Thereafter, the substrate on which the alignment layer is formed is maintained for a proper time in a drying furnace and a curing furnace, respectively, so that the moisture in the alignment layer is removed and cured to maintain an appropriate hardness.

Next, surface treatment of the alignment layer is performed to form polymer chains having a certain orientation on the cured alignment layer surface. The alignment layer surface treatment process is generally performed by rubbing.

The fourth step st 4 is a step of printing and dispersing the seal pattern.

The seal pattern in the liquid crystal cell has two functions of forming a cell gap for liquid crystal injection and preventing leaking of the injected liquid crystal. Also, a seal having a constant size to maintain a precise and uniform cell gap between the color filter substrate and the array substrate is provided. Will be scattered.

In the fifth step (st 5), after the spacer spreading process is completed, the color filter substrate and the array substrate are bonded together.

The sixth step (st 6) is a step of cutting the prepared liquid crystal cell into a unit liquid crystal cell.

In general, a liquid crystal cell is formed of a plurality of liquid crystal cells on a large glass substrate, and then separated into one liquid crystal cell.

A seventh step (st 7) is a step of injecting liquid crystal into the liquid crystal cell and sealing the liquid crystal inlet.

4 is a perspective view for explaining an alignment film rubbing process according to an embodiment of the present invention.

As illustrated, the alignment layer rubbing device includes a stage 125 for positioning the substrates 111 and 113, a rubbing roll 129 to which the rubbing cloth 127 is attached, and a support 131 for supporting the rubbing roll 129. ).

In this case, a groove 135 is formed on the stage 125 to prevent distortion of the substrates 111 and 113, and the groove 135 is configured to allow the substrates 111 and 113 to be seated.

The alignment layer rubbing process is performed on the substrates 111 and 113 through the alignment layer rubbing device configured as described above.

The substrates 111 and 113 on which the alignment layer 133 is formed are seated in the grooves 135 formed on the stage 125, and the stage 125 on which the substrates 111 and 113 are seated is the rubbing cloth 127. ) Is placed while maintaining a constant gap with the rubbing roll 129 wound.

Next, the rubbing roll 129 rotates at a high speed. In this stage, the rubbing cloth 127 attached to the surface of the rubbing roll 129 contacts the alignment layer 133 on the substrates 111 and 113. By rubbing the surface of the alignment layer 133, an alignment pattern is formed on the surface of the alignment layer 133.

More precisely, the rubbing cloth 127 attached to the surface of the high-speed rotating rubbing roll 129 is in contact with the substrates 111 and 113, and the stage 125 moves in one direction at a constant speed so that the substrate ( The surfaces of the alignment layers 133 on the 111 and 113 are rubbed with the rubbing cloth 127 so that the polymer chains (side chains) formed therein on the surfaces of the alignment layers 133 are aligned in one direction. Therefore, the surface of the alignment film 133 is more precisely aligned with the polymer chain (side chain) on the surface of the alignment film 133 in a constant direction.

FIG. 5 is a cross-sectional view schematically illustrating a state of a substrate seated on a stage of FIG. 4.

As illustrated, the stage 125 is provided with a groove (135 of FIG. 4) for preventing the substrates 111 and 113 from twisting, and the substrates 111 and 113 having the alignment layer 133 are formed on the stage ( 125 is seated and positioned in the groove (135 of Figure 4) configured on.

The groove 135 formed on the stage 125 has a side surface having a predetermined inclination, which is to facilitate the mounting and detachment of the substrates 111 and 113.

As described above, by forming the grooves 135 of FIG. 4 to allow the substrates 111 and 113 to be seated on the stage 125 where the substrates 111 and 113 are positioned during the alignment film rubbing process. The warpage of the substrates 111 and 113 can be prevented. As a result, it is possible to solve the problem of reducing the contrast ratio due to the defective rubbing axis caused by the twisting of the substrates 111 and 113.

The present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention.

As described above, according to the present invention by forming a groove on the stage where the substrate is located during the alignment film rubbing process to prevent the distortion of the substrate, the contrast ratio due to rubbing axis defect caused by the distortion of the substrate It is effective in solving the problem of decreasing the contrast ratio.

Claims (3)

A substrate coated with an alignment film; A stage on which the substrate is seated and a groove is formed; Located on the top of the stage, a rubbing roll attached to the rubbing cloth and a support for supporting the rubbing roll And the substrate is seated in a groove configured on the stage. The method of claim 1, And a groove formed in the stage is configured to have a side of a constant slope. Placing the substrate coated with the alignment film in a groove formed on the stage; Positioning the stage on which the substrate is seated horizontally spaced apart from a rubbing roll on which a rubbing cloth is wound; Rotating the rubbing roll and advancing the stage toward the rubbing roll; Forming an alignment pattern on the surface of the alignment film of the substrate by the rubbing cloth of the rotating rubbing roll Alignment film rubbing process comprising a.

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