JP2008257105A - Rubbing processing device and manufacturing method of liquid crystal display device by the rubbing processing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a rubbing processing device capable of preventing display unevenness caused when performing continuous rubbing processing on a liquid crystal device in large quantity. <P>SOLUTION: The rubbing processing device has a stage 2 holding a substrate 1 and a rubbing roller 6 performing rubbing processing, and relatively moves the substrate 1 and stage 2 in a predetermined direction with respect to the rubbing roller 6 while fixing the rubbing roller at a desired angle with respect to a longitudinal direction of the substrate 1 and rotating it to perform rubbing processing on an alignment film surface formed on a surface of the substrate 1 held on the stage 2. The rubbing processing device is equipped with a positioning mechanism 10 which positions the substrate to be processed at a position on the stage 2, the position being different for each substrate. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to a rubbing processing apparatus used for manufacturing a liquid crystal display device and a method for manufacturing a liquid crystal display device using the rubbing processing apparatus.

A liquid crystal display device using a liquid crystal panel is used in many electrical equipment products such as AV equipment and OA equipment because of its low power consumption, thinness, and light weight. In recent years, with the increasing demand for these products, it has become important to rapidly increase the definition and improve the image display quality. In such a method for manufacturing a liquid crystal display device, a rubbing process, which is a process for forming fine streaks on the surface of an alignment film for aligning liquid crystals, has a significant effect on image display quality.

In the conventional rubbing process, the rubbing roller is rotated to perform a rubbing process in a specific direction with respect to the alignment film surface. On the substrate on which the alignment film held on the stage is formed, wiring, terminals, A step due to a pattern such as a light shielding film is generated.

When a rubbing process is performed on a substrate on which an alignment film having a pattern step as described above is formed, the unevenness of the pattern is pressed against the surface of the rubbing cloth, and the portion that contacts the convex portion and the concave portion are contacted The surface state of the hair end of the rubbing cloth will be different at the part to be done. In particular, when a rubbing process is performed continuously in large quantities, in the conventional rubbing apparatus, the part in contact with the pattern is reproduced in the same part of the rubbing cloth, and the difference in the surface state of the hair tip depending on the location is fixed. This unevenness of the surface state of the cloth is also transferred to the alignment film in the display region, causing alignment unevenness in the display region. As a result, display unevenness due to alignment unevenness occurs, which has been a factor that deteriorates the yield.

In addition, as a method of reducing display unevenness due to such a rubbing process, in Patent Document 1, a method of rubbing while swinging a substrate to be processed, and in Patent Document 2, unevenness of the surface state of the rubbing cloth is performed. A method of providing a hair running-in means for running-in is disclosed.

JP-A-10-319402 JP-A-5-34694

However, when the rubbing process is performed while swinging as in Patent Document 1, the substantial direction of the rubbing process is not constant, and there is a problem that the process itself becomes unstable. In addition, even when the hair running-in means as in Patent Document 2 is provided, there is a problem in durability such that the rubbing cloth is easily worn out or damaged.

SUMMARY OF THE INVENTION An object of the present invention is to provide a rubbing processing apparatus and method capable of preventing a display unevenness due to rubbing processing and realizing a liquid crystal display device with high image display quality.

A rubbing apparatus according to the present invention includes a stage for holding a substrate having an alignment film formed on a surface thereof, and a rubbing roller for rubbing the alignment film surface, and the rubbing roller is desired in the longitudinal direction of the substrate. The substrate and the stage are relatively moved in a predetermined direction with respect to the rubbing roller while rotating at a fixed angle, and a rubbing process is performed on the surface of the alignment film formed on the surface of the substrate held on the stage. Is provided with a positioning mechanism for positioning at different positions on the stage for each substrate to be processed.

According to the present invention, it is possible to prevent display unevenness when a rubbing process is performed on a substrate having an alignment film formed on the surface thereof in a liquid crystal display device, thereby improving yield and performing a large amount of continuous rubbing process. It is possible to obtain the advantageous effect that productivity can be dramatically improved.

Embodiment 1 FIG.
Hereinafter, a rubbing apparatus according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is an external view seen from the upper side of the apparatus showing the configuration of the rubbing treatment apparatus according to the first embodiment, and FIG. 2 is a sectional view taken along the line AA in FIG. Note that the drawings are schematic and do not reflect the exact size of the components shown. In the drawings, the same reference numerals are used for portions common to the above-described components, and detailed description thereof is omitted. Hereinafter, the same applies to other drawings.

As shown in FIG. 1, the rubbing apparatus of the first embodiment includes a stage 2 for holding a substrate 1 (an arrangement of panels in the substrate is indicated by a dotted line) on which an alignment film for aligning liquid crystals is formed. Alignment pins 3 and alignment grooves 4 for positioning the substrate 1 at predetermined positions, a suction hole 5 as a holding mechanism for sucking and holding the positioned substrate 1 on the stage 2, and rotation about the rotation axis XX On the other hand, it comprises a rubbing roller 6 that rubs the surface of the substrate 1 held on the stage 2 and performs a rubbing process. In the drawing, the direction of the rotation axis XX is changed so that the rubbing roller 6 can change the angle θ with respect to the traveling direction of the substrate 1 and the stage 2 (shaded hatched arrow direction in the figure) so that the rubbing process in a desired direction can be performed. As indicated by the shaded arrows, it can be rotated and fixed at a desired angle.

Further, as shown in FIG. 2, the alignment pin 3 includes a ball screw 7 and a motor 8 for opening / closing the alignment pin 3, and a motor 8 connected to the motor 8 to control the operation of the motor 8 to determine a positioning position for each processing substrate. A drive mechanism including a control unit 9 such as a sequencer is attached to constitute a positioning mechanism 10 as a whole. The controller 9 determines the overall operation of the positioning mechanism 10. In addition, a drive mechanism (not shown) is also provided that moves up and down the alignment pin 3 and the entire drive mechanism into and out of the stage 2 as indicated by arrows in the drawing before and after the positioning operation.

Next, the operation of the rubbing processing apparatus according to the first embodiment will be described with reference to FIG. First, when processing the substrate 1a having the first alignment film formed on the surface, the alignment pin 3 is positioned at a predetermined position. Here, for example, as shown in FIG. 3A, the substrate 1a and the stage 2 are set on the left side in the traveling direction. After the positioning, the substrate 1a is held at a predetermined position on the stage 2 by the suction holes, and then the alignment pins 3 are lowered and stored in the stage 2 so as not to interfere with the rubbing process. The substrate 1a passes under the rubbing roller 6 rotating in this state by the method indicated by the arrow in the drawing, and a rubbing process in a desired direction is performed on the surface of the alignment film formed on the surface of the substrate 1a. The rubbing process direction is a direction perpendicular to the rotation axis XX of the rubbing roller 6.

Thereafter, when the next substrate 1b is continuously processed, the substrate is positioned by a predetermined position different from that shown in FIG. Here, different positions in the direction perpendicular to the traveling direction of the substrate 1b and the stage 2, for example, a predetermined position on the right side in the traveling direction of the substrate 1b and the stage 2 as shown in FIG. The predetermined positions described with reference to FIGS. 3A and 3B are determined by controlling the operation of the positioning mechanism 10 by the control unit 9 described when the configuration is described. The subsequent operation is the same as that described with reference to FIG. Thereafter, even when the substrate is continuously processed, the rubbing process is continued by sequentially positioning to a predetermined position different from the positioning position of the previous substrate.

Further, in the above description, the predetermined positions at which the respective substrates 1 are positioned are described at extremely different positions on the left side and the right side in the traveling direction of the substrate and the stage. Specifically, FIG. 3), a plurality of fixed positions are determined at appropriate positions between FIG. 3B, and the positions are sequentially positioned at different positions for each substrate. The order of selecting the fixed positions may be selected in an order determined for each fixed position, or may be selected in a random order and the process may be advanced. Further, the processing may be performed by selecting an arbitrary position between two predetermined fixed positions at random without determining a fixed position for positioning. The control unit 9 also controls the operation of the positioning mechanism 10 for these operations. Specifically, the control unit 9 uses a sequencer, a personal computer, etc., as appropriate, and appropriately uses the rotation amount data of the motor 8 corresponding to the positioning position, the number of times of substrate processing, or the random number data generated by random number generation. Is feasible. Further, as is clear from FIG. 3, the alignment groove 4 is provided flat in a direction perpendicular to the traveling direction of the substrate 1 and the stage 2, and the alignment pin 3 opens and closes in a direction perpendicular to the traveling direction of the substrate 1. Therefore, it is possible to easily position the substrate 1 and the stage 2 at different positions in the direction perpendicular to the traveling direction.

Then, the effect | action of this Embodiment 1 is demonstrated using FIG. 4 and FIG. FIG. 4 is a diagram for explaining, as a comparative example, alignment unevenness due to pattern transfer in a panel generated by a conventional rubbing treatment apparatus. FIG. 5 is a diagram for explaining the action of alleviating the occurrence of alignment unevenness in the first embodiment.

First, the terminal electrode 111 will be described as an example of a pattern in a panel (outer shape is indicated by a dotted line, the same applies to FIG. 5) arranged on the substrate 101 as shown in FIG. In this case, since the portion (being a convex portion) that contacts the terminal electrode 111 is more strongly contacted, a region (referred to as a pattern mark) having a different surface state of the hair tip is generated in the same portion as the pattern shape. The position of the pattern marks on the surface of the rubbing cloth is shifted depending on each substrate due to the positional relationship between the rubbing roller and the substrate, but the direction perpendicular to the direction of movement of the substrate and the stage does not change. Pattern marks are fixed on the surface. As a result, as shown in FIG. 4, alignment unevenness (pattern transfer region 112) in which the pattern of the terminal electrode 111 is transferred in a direction parallel to the advancing direction of the substrate and the stage occurs and is visually recognized as display unevenness.

On the other hand, in the process of the first embodiment, even after a large number of substrates 1 are processed, the alignment unevenness (pattern transfer region 12) to which the pattern of the terminal electrode 11 is transferred as shown in FIG. To be homogenized. This is because the relationship between the rubbing roller 6 and the substrate 1 is changed by changing the positioning position for each substrate in a direction perpendicular to the traveling direction of the substrate 1 and the stage 2, so that it is perpendicular to the traveling direction of the substrate 1 and the stage 2. This is because the pattern marks on the surface of the rubbing cloth are not fixed in any direction. In this manner, the alignment unevenness (pattern transfer region 12) in the panel is made uniform throughout, so that the display unevenness can be made invisible.

As described above, the rubbing apparatus according to the first embodiment includes the positioning mechanism 10 for positioning a plurality of substrates at different positions on the stage 1 for each substrate to be processed. Therefore, there is an advantageous effect that it is possible to prevent alignment unevenness on the surface of the alignment film when the rubbing treatment is performed on the substrate on which the alignment film is formed on the liquid crystal display device.

Further, in the apparatus and method of the first embodiment, the positional relationship between the rubbing roller 6 and the substrate 1 varies for each substrate, but the substrate 1 is held by suction at a fixed position on the stage 2. Therefore, as the processing of each substrate 1, the relationship (rubbing processing angle) between the rubbing processing direction and the substrate direction does not change during the rubbing processing, and the rubbing processing can be performed stably.

In the first embodiment, no particular exception is made at the position where the substrate 1 is disposed. However, FIG. 6 shows a pattern arrangement diagram on a substrate on which an alignment film used for manufacturing a general liquid crystal display device is formed. On the substrate 1 to be actually processed in this way, FIG. In general, the patterns of the terminal electrodes 11 are arranged at equal intervals of the pitch p, and the panels 13 are also arranged at equal intervals of the pitch P. In view of this situation, for movements that are the same as these pitches or an integral multiple of the pitch, the effect of uniformizing the pattern trace area as a whole is lost because almost the same pattern trace is formed on the rubbing cloth. . As described above, the position different for each substrate is selected from positions excluding an integer multiple of the pitch of the patterns arranged at equal intervals on the substrate 1 such as the terminal electrode 11 and the panel 13 to efficiently reduce the alignment unevenness. Is preferable.

Embodiment 2. FIG.
In the first embodiment, a method is used in which different positions for each substrate are selected in the direction perpendicular to the direction in which the stage 2 or the rubbing roller 6 is moved, and positioning is performed by the alignment pins 3. In the second embodiment, a method will be described in which a position different for each substrate is changed to a position where the substrate angle is changed. FIG. 7 shows an external view of the rubbing processing apparatus according to the second embodiment as viewed from the top. As shown in FIG. 7, the alignment pin 3 is operated to rotate the substrate, and the substrate is positioned at a position where the substrate angle is changed with respect to the moving direction of the position stage 2 or the rubbing roller 6 which is different for each substrate. For example, the first substrate to be processed is set to the position of the substrate 1a in the drawing, and the substrate to be subsequently processed is set to the position 1b in the drawing (the position of the substrate and the position of the arament pins 3 are indicated by dotted lines). Also by this method, the alignment unevenness (pattern transfer region) in the panel can be uniformized as in the first embodiment, and the display unevenness can be made invisible.

Also in this method, as in the first embodiment, a plurality of fixed positions are determined at appropriate positions having different angles, and the positions are sequentially positioned at different positions for each substrate. The order of selecting the fixed positions may be selected in an order determined for each fixed position, or may be selected in a random order and the process may be advanced. Further, the processing may be performed by selecting a position corresponding to an arbitrary angle randomly between two predetermined substrate angles without determining a fixed position for positioning.

In the first and second embodiments, the method of moving the substrate 1 and the stage 2 to the rubbing roller 6 rotating at a fixed position and performing the rubbing process is used. However, the substrate 1 and the stage 2 are used. Since the same rubbing processing action can be obtained if the roller moves relative to the rubbing roller 6, the substrate 1 and the stage 2 are fixed, and the rubbing roller 6 is kept at a constant angle with respect to the substrate 1 and the stage 2. The rubbing process may be carried out by scanning while rotating as it is, and the same effects as those of the first and second embodiments can be obtained. Further, in this case, the same effect can be obtained if the traveling direction of the substrate 1 and the stage 2 described in the first and second embodiments is read as the direction of relative movement with respect to the rubbing roller 6 of the substrate 1 and the stage 2. The explanation is valid.

Embodiment 3 FIG.
Next, the configuration of the liquid crystal display device according to Embodiment 3 will be described with reference to FIG. Here, as an example, a TFT (Thin Film Transistor) type liquid crystal display device will be described. As shown in the figure, the liquid crystal display device 200 includes a switching element substrate 210, a color filter substrate 220, and a liquid crystal 230 filled between the switching element substrate 210 and the color filter substrate 220.

The switching element substrate 210 includes an alignment film 212 that aligns the liquid crystal 230 on one surface of the glass substrate 211, a pixel electrode 213 that is provided below the alignment film 212 and applies a voltage for driving the liquid crystal 230, and the pixel electrode 213. A switching element 214 such as a TFT for supplying a voltage, an insulating film 215 covering the switching element 214, a terminal 216 for receiving a signal supplied to the switching element 214 from the outside, and a signal input from the terminal 216 to the counter electrode A transfer electrode 217 and the like are included. In addition, a polarizing plate 231 is provided on the other surface of the glass substrate 211.

On the other hand, the above-described color filter substrate 220 is disposed under one of the alignment film 222 for aligning the liquid crystal 230 on one surface of the glass substrate 221 and the alignment film 222, and an electric field between the pixel electrode 213 on the switching element substrate 210. A common electrode 223 for driving the liquid crystal 230, a color filter 224 provided under the common electrode 223, a light shielding layer 225, and the like. In addition, a polarizing plate 232 is provided on the other surface of the glass substrate 221.

Further, the switching element substrate 210 and the color filter substrate 220 are bonded together via a seal 233. Further, the transfer electrode 217 and the common electrode 223 are electrically connected by a transfer material 234, and a signal input from the terminal 216 is transmitted to the common electrode 223. In addition, the liquid crystal display device 200 includes a control board 235 that generates a drive signal, an FPC (Flexible Printed Circuit) 236 that electrically connects the control board 235 to the terminal 216, a backlight unit (not shown) that serves as a light source, and the like. It has.

The liquid crystal display device 200 operates as follows. For example, when an electric signal is input from the control substrate 235, a driving voltage is applied to the pixel electrode 213 and the common electrode 223, and the molecular direction of the liquid crystal 230 is changed in accordance with the driving voltage. The light emitted from the backlight unit is transmitted or blocked to the outside through the switching element substrate 210, the liquid crystal 230, and the color filter substrate 220, whereby an image or the like is displayed on the liquid crystal display device 200.

The liquid crystal display device 200 is an example and may have other configurations. The operation mode of the liquid crystal display device 200 may be a TN (Twisted Nematic) mode, an STN (Super Twisted Nematic) mode, a ferroelectric liquid crystal mode, or the like. The driving method may be a simple matrix, an active matrix, or the like, and a color filter substrate. 220 may be a liquid crystal display device using a horizontal electric field method in which a common electrode 223 provided on 220 is provided on the switching element substrate 210 side and an electric field is applied to the liquid crystal 230 in the horizontal direction between the pixel electrode 213.

Next, a manufacturing method of the liquid crystal display device according to the third embodiment will be described. Since a general method is used for manufacturing the switching element substrate 210 and the color filter substrate 220, a brief description will be given. The switching element substrate 210 has a switching element 214, a pixel electrode 213, a terminal 216, and a transfer electrode 217 formed on one surface of the glass substrate 211 by repeatedly using a pattern forming process such as film formation, patterning by photolithography, and etching. Manufactured by forming. Similarly, the color filter substrate 220 is manufactured by forming the color filter 224 and the common electrode 223 on one surface of the glass substrate 221.

Subsequently, a characteristic assembly process in the third embodiment will be described with reference to a flowchart shown in FIG. First, in the substrate cleaning process, the switching element substrate 210 on which the pixel electrode 213 is formed is cleaned (S1). Next, in the alignment film forming step, an alignment film 212 is formed on one surface of the switching element substrate 210 (S2). In this step, for example, an alignment film 212 made of an organic film is applied by a printing method, and is baked and dried by a hot plate or the like.

After that, in the rubbing process, the substrate on which the alignment film 212 is formed is subjected to a rubbing process by using the rubbing apparatus described in Embodiment 1, and the alignment film 212 is aligned (S3). Similarly to S1 to S3, the color filter substrate 220 on which the common electrode 223 is formed is subjected to cleaning, formation of the alignment film 222, and rubbing processing using the rubbing processing apparatus described in Embodiment 1. . By using the rubbing processing apparatus described in the first embodiment, even when a large amount of continuous rubbing processing is performed, pattern marks are not fixed to the rubbing roller and are uniformized as a whole.

Subsequently, in the seal coating process, the sealing material 233 is coated on one surface of the switching element substrate 210 or the color filter substrate 220 by a dispensing method using a nozzle or a screen printing method (S4). For the sealing material 233, for example, a thermosetting resin such as an epoxy adhesive or an ultraviolet curable resin was used.

Next, in the transfer material application process, the transfer material 234 is applied to one surface of the switching element substrate 210 or the color filter substrate 220 (S5). In the spacer spraying step, spacers are sprayed on one surface of the switching element substrate 210 or the color filter substrate 220 (S6). This step is performed, for example, by dispersing the spacers by a wet method or a dry method.

Thereafter, in the bonding step, the switching element substrate 210 and the color filter substrate 220 are bonded together (S7). Subsequently, in the seal curing step, the seal 233 is completely cured with the switching element substrate 210 and the color filter substrate 220 bonded together (S8). This step is performed, for example, by applying heat according to the material of the seal 233 or by irradiating ultraviolet rays. Next, in the cell dividing step, the bonded substrates are disassembled into individual cells (S9). In the liquid crystal injection step, liquid crystal is injected from the liquid crystal injection port (S10). This step is performed, for example, by filling the liquid crystal 230 by vacuum injection from the liquid crystal injection port. Further, in the sealing step, the liquid crystal inlet is sealed (S11). This step is performed, for example, by sealing with a photocurable resin and irradiating with light.

About the process from bonding of the above S7-S13 to liquid crystal sealing, the liquid crystal injection method from the normal injection port was demonstrated as an example. However, as another liquid crystal injection method, the seal 233 has a pattern shape without an injection port, and the liquid crystal 230 is formed in a droplet state on the switching element substrate 210 or the color filter substrate 220. A method in which the seal 233 is cured after the switching element substrate 210 and the color filter substrate 220 are bonded so as to sandwich the substrate, a so-called drop injection method may be used.

Finally, the polarizing plates 231 and 232 are attached to the cell in the polarizing plate attaching step (S12), and the control substrate 235 is mounted in the control substrate mounting step (S13), thereby completing the liquid crystal display device 200.

As described above, in the liquid crystal display device according to the third embodiment, a plurality of substrates are manufactured by using a rubbing processing device including a positioning mechanism that positions each substrate to be processed at a different position on the stage. Even when the substrate is rubbed continuously, it does not cause display unevenness when the substrate having the alignment film formed on the surface is rubbed, thereby improving the yield in the manufacture of the liquid crystal display device and the mass substrate. An advantageous effect that continuous rubbing treatment can be achieved and productivity can be dramatically improved is obtained.

In the third embodiment, the method for manufacturing a liquid crystal display device using the rubbing apparatus of the first embodiment for the rubbing process has been described. However, the same effects as those of the third embodiment can be obtained even when the rubbing processing device according to the second and second embodiments is used instead of the rubbing processing device of the first embodiment. Can do.

It is the external view which showed the rubbing processing apparatus in Embodiment 1 of this invention. It is sectional drawing which showed the rubbing processing apparatus in Embodiment 1 of this invention. It is a figure explaining operation | movement of the rubbing processing apparatus in Embodiment 1 of this invention. It is explanatory drawing of the orientation nonuniformity which generate | occur | produces in the conventional rubbing processing apparatus. It is operation | movement explanatory drawing of the rubbing processing apparatus in Embodiment 1 of this invention. It is a pattern arrangement view on a substrate on which an alignment film used for manufacturing a general liquid crystal display device is formed. It is the external view which showed the rubbing processing apparatus in Embodiment 2 of this invention. It is sectional drawing of the liquid crystal display device in Embodiment 3 of this invention. It is a flowchart which shows the assembly process in the manufacturing method of the liquid crystal display device in Embodiment 3 of this invention.

Explanation of symbols

1, 1a, 1b Substrate, 2 stage, 6 rubbing roller, 10 positioning mechanism, 200 liquid crystal display device, 212, 222 alignment film.

Claims (10)

A stage for holding a substrate having an alignment film formed on the surface; and a rubbing roller for rubbing the alignment film surface. The rubbing roller is fixed and rotated at a desired angle with respect to the longitudinal direction of the substrate. A rubbing apparatus that moves the substrate and the stage relative to the rubbing roller in a predetermined direction and performs a rubbing process on the alignment film surface formed on the surface of the substrate held on the stage,
A rubbing processing apparatus comprising: a positioning mechanism that positions each substrate to be processed at a different position on the stage when a plurality of the substrates are sequentially rubbed. 2. The rubbing apparatus according to claim 1, wherein the position on the stage which is different for each substrate is different in a direction perpendicular to a predetermined direction in which the substrate and the stage are moved relative to the rubbing roller. 3. The rubbing apparatus according to claim 2, wherein the position on the stage which is different for each substrate is selected from positions excluding an integer multiple of a pitch of patterns arranged at equal intervals on the substrate. 2. The rubbing apparatus according to claim 1, wherein the position on the stage which is different for each substrate is a position where the substrate angle with respect to a predetermined direction in which the substrate and the stage are moved relative to the rubbing roller is changed. The rubbing processing apparatus according to claim 1, wherein the position on the stage different for each substrate is selected from any of a plurality of fixed positions. 6. The rubbing apparatus according to claim 5, wherein the position on the stage which is different for each substrate is selected in an order determined from any of a plurality of fixed positions. 6. The rubbing apparatus according to claim 5, wherein the position on the stage different for each substrate is selected in a random order from any of a plurality of fixed positions. The rubbing processing apparatus according to claim 1, wherein the position on the stage different for each substrate is an arbitrary position selected at random between two predetermined fixed positions. The rubbing processing apparatus according to claim 4, wherein the position on the stage different for each substrate is a position corresponding to an arbitrary angle selected at random between two predetermined substrate angles. A method for manufacturing a liquid crystal display device, wherein the rubbing treatment is performed by the rubbing treatment device according to claim 1.

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