JP2001154198A - Rubbing device, method of rubbing substrate for liquid crystal device, and liquid crystal device manufactured by the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of rubbing liquid crystal device always ensuring stable display characteristics and a rubbing device used for it. SOLUTION: The rubbing device 48 is provided with a stage 40 on which a substrate 10 with an alignment layer formed on its one surface is mounted, a rubbing roller 41 brought into contact with the substrate 10 to rubbing-treat the alignment layer, a torque detection circuit 42 to detect the rotational torque of the rubbing roller at an end part of the substrate and a motor moving up and down to move the stage 40 so as to maintain the rotational torque within a specified range. As the rotational torque is thereby set up within the specified range for the individual substrates, the substrates can be rubbing-treated always with the constant rotational torque value even when, for example, a plurality of substrates with variation in thickness are treated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of a liquid crystal device, and particularly to the technical field of rubbing of an alignment film.

[0002]

2. Description of the Related Art A liquid crystal device is constituted by sandwiching a liquid crystal layer between a counter substrate and an active matrix substrate, and performs display by applying a voltage to the liquid crystal layer to change optical characteristics of liquid crystal molecules. An alignment film is disposed on a surface of the opposing substrate and the active matrix substrate that are in contact with the liquid crystal layer, and the alignment film determines the arrangement of the liquid crystal molecules. The alignment film is formed by performing a rubbing method of rubbing the surface of an organic film such as polyimide with a cloth or the like in a predetermined direction.

A specific rubbing method is as follows.
First, a substrate having a polyimide film is placed on a mounting table of a rubbing apparatus with the polyimide film facing upward. Next, a rubbing roller with a rubbing cloth attached around the roller is arranged so as to be in contact with the polyimide film. Form. In such a rubbing apparatus, the positional relationship between the rubbing roller and the substrate is set to a predetermined value on the basis of a certain substrate, and the rubbing process of another substrate is always performed with this value fixed. I was going.

[0004]

However, since the thickness differs between the substrates, if the rubbing treatment is performed with the positional relationship between the rubbing roller and the substrate set to a predetermined value, the rubbing strength varies between the substrates. I was

For example, when a thin substrate is compared with a thick substrate, the value of the contact length between the rubbing cloth and the alignment film is smaller in the thin substrate than in the thick substrate, and the rubbing strength is smaller. For this reason, the alignment of the liquid crystal molecules is weakened, which causes tilt unevenness of the liquid crystal molecules and the generation of reverse twist domains. On the other hand, in the case of a thick substrate, the rubbing strength is high, so that the alignment of the liquid crystal becomes too strong, which causes the generation of minute foreign matters due to the shaving of the alignment film and the reduction of the tilt of the liquid crystal molecules. TFT for liquid crystal drive device
When the polarity inversion driving is performed between pixels or between lines using the above, disclination occurs due to generation of a horizontal electric field. Such uneven tilt, reverse twist, and disclination significantly degrade the display quality of the liquid crystal device. In particular, when such a liquid crystal device is used as a light valve of a projection type display device, since the projection type display device enlarges and projects, alignment unevenness of the liquid crystal causes a fatal display defect.

As described above, the conventional rubbing method using a rubbing device has a problem that a liquid crystal device having constantly constant display characteristics cannot be obtained, resulting in poor production efficiency.

The present invention has been made in order to solve such a problem, and an object of the present invention is to provide a rubbing device and a rubbing method capable of obtaining a liquid crystal device having always constant display characteristics.

[0008]

In order to solve such a problem, the present invention employs the following configuration.

A rubbing apparatus according to the present invention is characterized in that a substrate having an alignment film formed on one surface thereof is mounted on a mounting table with the alignment film facing upward, and the substrate is in contact with the substrate and one end to the other end of the substrate. A rubbing roller for rubbing the alignment film by moving toward the portion, a torque detection mechanism for detecting a rotation torque of the rubbing roller at one end of the substrate, and the rotation torque being predetermined based on the detection result. And a moving mechanism for moving the rubbing roller or the mounting table described above.

According to such a configuration, it is possible to adjust the positions of the rubbing roller and the mounting table for each substrate and set the rotational torque within a predetermined range, that is, to set the rubbing pressure within a predetermined range. . For example, even if a plurality of substrates having thickness variations are processed, the rubbing process can be always performed on each substrate at a constant rubbing pressure. As a result, there is an effect that a rubbing strength does not vary between substrates and a liquid crystal device having stable product characteristics can be provided at all times. Further, since the detection of the torque value is performed at one end of the substrate, the detection is performed outside the display area where the rubbing treatment of the liquid crystal device substrate is not required. The distance between the substrate and the rubbing roller is controlled based on this detection result, and the torque value is further detected. When the torque value falls within a predetermined range, the rubbing roller moves and the rubbing process is performed. Will be applied. Therefore, in the flow of the operation in which the rubbing roller contacts one end of the substrate and moves on the alignment film toward the other end, the torque value detection step, the rubbing roller-substrate distance control step, and the rubbing process are performed. Since the process can be performed, a rubbing treatment can be performed efficiently and with an appropriate rubbing strength.

The method of rubbing a substrate for a liquid crystal device according to the present invention comprises the steps of: (a) detecting a rotational torque value of a rubbing roller disposed in contact with one end of the liquid crystal device substrate having an alignment film; A step of controlling a distance between the substrate and the rubbing roller by the rotation torque value,
(C) repeating the steps (a) and (b) until the rotation torque value falls within a predetermined range; and (d) holding the distance when the rotation torque value falls within a predetermined range. And moving the rubbing roller relatively from one end to the other end of the substrate.

According to such a configuration of the present invention, the rubbing pressure can be set within a predetermined range by detecting the rotational torque for each substrate and controlling the distance between the substrate and the rubbing roller. For example, even if a plurality of substrates having thickness variations are processed, it is possible to always perform a rubbing process on each substrate with a constant rotational torque value, that is, a constant rubbing pressure. As a result, it is possible to obtain a liquid crystal device in which rubbing strength does not vary between substrates and product characteristics are always stable.

Further, in the step (d), the distance when the rotational torque value falls within a predetermined range is recorded, and after the moving direction of the rubbing roller with respect to the substrate is set, the distance is maintained. Then, the rubbing roller relatively moves. According to this configuration, it is possible to cope with all rubbing directions and bias rubbing.

Further, the liquid crystal device substrate has an active area and a detection area for detecting the rotational torque. According to this configuration, since the detection region for rubbing torque measurement is formed, the positional relationship between the rubbing roller and the substrate is adjusted in the detection region,
There is an effect that rubbing processing with a constant intensity can be performed on the active area including the display unit.

Further, the active area has a display pixel area and a peripheral drive circuit area for controlling display of the display pixel area. According to such a configuration, the present invention can be applied to a liquid crystal device integrated with a driving circuit.

Further, the detection area is formed at an end of the liquid crystal device substrate. According to such a configuration, since the detection area is located at the end of the substrate, the operation of detecting the rotational torque value in such an area causes the rubbing roller to move on the alignment film toward the other end. In the flow, the step of detecting the rotational torque value, the step of adjusting the position of the rubbing roller and the substrate, and the step of rubbing can be performed, so that the rubbing can be performed efficiently and with appropriate rubbing strength.

Further, the steps (a) to (d) are carried out for different liquid crystal device substrates. According to such a configuration, even when substrates having different thicknesses are processed, there is an effect that a rubbing strength does not vary between the substrates and a liquid crystal device having stable product characteristics can be always obtained.

The substrate for a liquid crystal device according to the present invention is characterized by being manufactured by the rubbing method for a substrate for a liquid crystal device described above. With such a configuration, there is no variation in the rubbing strength between different substrates, so that it is possible to obtain a liquid crystal device substrate with stable product characteristics.

A liquid crystal device according to the present invention is characterized by using the above-described substrate for a liquid crystal device. Such a liquid crystal device is
Good and stable display quality can be obtained.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. As one embodiment of the present invention,
A case where a TFT array substrate is used as a substrate for a liquid crystal device will be described.

First, the structure of a liquid crystal device in which a substrate rubbed using the rubbing device of the present invention is incorporated will be briefly described with reference to FIGS. FIG. 6 is a perspective view of the liquid crystal device substrate of the present invention during a rubbing process. In the active area 100, a plurality of TFT arrays and a peripheral driver are formed. Further, a detection area 101 for detecting the rotation torque of the rubbing roller is formed at the end of the substrate. TFT after rubbing treatment
When the liquid crystal device is assembled, a part of the rotation torque detecting unit 101 of the rubbing roller may be cut off from the array substrate as needed. FIG. 4 is an equivalent circuit of various elements, wiring, and the like in a plurality of pixels formed in a matrix forming an image forming area of the liquid crystal device. FIG. 4 shows a data line,
FIG. 5 is a plan view of a plurality of pixel groups adjacent to each other on a TFT array substrate on which a scanning line, a pixel electrode, a light-shielding film, and the like are formed. FIG. In each drawing, the scale is appropriately set for each layer and each member so that each layer and each member have a size that can be recognized in the drawings.

As shown in FIG. 5, the liquid crystal device 31 includes a TFT array substrate 10 as a substrate for the liquid crystal device, and an opposing substrate 20 disposed opposite thereto, and a liquid crystal layer 50 is sandwiched between both substrates. It is configured. TFT array substrate 1
0 and the opposing substrate 20 have alignment films 16 and 22 on the side in contact with the liquid crystal layer 50, respectively. Alignment films 16 and 2
2 is subjected to rubbing treatment in directions intersecting each other, and the liquid crystal layer 50 adopts a predetermined alignment state by the alignment films 16 and 22 in a state where no electric field is applied from the pixel electrode 9a.

As shown in FIG. 6, an active area 100 is formed on the substrate for a liquid crystal device of the present invention, and a detection area 101 for detecting a rotational torque of a rubbing roller is formed at an end of the substrate.

As shown in FIG. 4, the active area 100 of the liquid crystal device substrate 10 includes a display pixel area and a peripheral drive circuit area for controlling display of the display pixel area. In the display pixel area, a plurality of scanning lines 3 and a plurality of data lines 6 intersecting with each other are arranged, and a pixel electrode 9a is provided for each intersection.
Are arranged, a thin film transistor (hereinafter, referred to as TFT) 30 for controlling the pixel electrode 9 a is arranged, and a capacitance line 3 b is arranged almost in parallel with the scanning line 3. Then, in the peripheral driving circuit area, the scanning signal G1
A scanning line driving circuit 104 for supplying G2,... Gn, and a data line driving circuit 105 for supplying image signals S1, S2,. As shown in FIG.
In the TFT array substrate 10, the TFT 3 is placed on the quartz substrate 60.
0, and a light-shielding film 11a
A base insulating film 12 disposed thereon, a semiconductor layer 1 constituting a part of a TFT 30 disposed on the base insulating film 12,
A gate insulating film 2 covering the semiconductor layer 1; a gate electrode 3a and a capacitor line 3b forming a part of the scanning line 3 disposed on the gate insulating film 2; and an insulating film 4 covering the gate electrode 3a and the capacitor line 3b Are formed. Further, a data line 6 is arranged on the insulating film 4, and the data line 6 is electrically connected to a source region 1 d of the semiconductor layer 1 via a contact hole 5 formed in the insulating film 4. Further, an interlayer insulating film 7 is disposed on the data line 6, and a pixel electrode 9 a disposed on the interlayer insulating film 7 is connected to a drain of the semiconductor layer 1 by a contact hole 8 formed in the insulating film 4 and the interlayer insulating film 7. It is electrically connected to the region 1e. Then, the pixel electrode 9a
On top, an alignment film 16 made of a polyimide film is arranged on the front surface of the substrate. The alignment film 16 has been subjected to a rubbing process in a direction along the scanning line 3, and a detailed processing method will be described later. The semiconductor layer 1 has an LDD structure in which low-concentration impurity regions 1b and 1c are arranged on both sides of the channel region 1a, and high-concentration impurity regions 1d and 1e are arranged on both sides of the channel region 1a. A part of the semiconductor layer 1 functions as a capacitor electrode 1f, and forms a storage capacitor 70 via the capacitor line 3b and the gate insulating film 2. On the other hand, in the detection region 110, the base insulating film 12, the insulating film 4, the interlayer insulating film 7, the alignment film 1 formed in the display switching element region.
6 are arranged to extend, and each film is formed in a solid film shape.

On the other hand, the opposing substrate 20 includes, for example, a light-shielding layer 23 provided in a grid pattern on a glass substrate 80, an opposing electrode 21 disposed so as to cover the
And an alignment film 22 made of a polyimide film disposed thereon. The alignment film 22 is rubbed in a direction substantially orthogonal to the rubbing direction of the alignment film 16 disposed on the TFT array substrate side.

The alignment films 16 and 22 formed on the TFT array substrate 10 and the counter substrate 20, respectively, are subjected to a rubbing process using a rubbing device described below.
The case where the rubbing process is performed on the array substrate 10 will be described as an example.

In the rubbing device 46 of the present invention, as shown in FIG. 1, the TFT array substrate 10 is placed, and the rubbing device 46 is placed in the vertical direction (the direction indicated by the arrow A in the drawing) and the linear direction parallel to the substrate plane (the drawing). , A rubbing roller 41 in which a rubbing cloth arranged so as to be in contact with the TFT array substrate 10 is wound around the roller, and a rubbing roller 41. And a rotation motor (not shown) for rotating.
Further, the rubbing device 48 has a torque detection circuit 42 as a torque detection mechanism for detecting the torque of the rotation motor.
, A position detection circuit 43 for detecting the position of the stage, data detected by the torque detection circuit 42 and the position detection circuit 43, a computer 44 for processing these data, and a data processed by the computer 44. A control circuit 45 for controlling the operation of the stage, a vertical movement motor 46 as a moving mechanism for moving the stage in the vertical direction instructed by the control circuit 45, and a stage instructed by the control circuit 45 to be parallel to the substrate plane. A substrate surface direction moving motor 47 is provided as a moving mechanism for moving in a linear direction. In the torque detection circuit 42,
The torque at one end of the substrate 10 on the rubbing process start side is detected, and the location where the torque is detected is the detection area 1 formed in a different area from the active area 100 shown in FIG.
01. In the present embodiment, the position of the rubbing roller 41 is fixed, the rubbing process is performed by moving the stage 40, and the distance between the substrate 10 and the rubbing roller 41 is controlled by moving the stage 40 up and down. However, the present invention is not limited to such a form. For example,
The stage 40 may be fixed, and the rubbing roller 41 itself may be moved in the vertical direction, in a direction parallel to the substrate surface, or both the stage 40 and the rubbing roller 41 may be movable.

Next, the operation of the rubbing device will be described with reference to FIGS.

First, a TFT array substrate 10 shown in FIG. 6 in which a polyimide film serving as an alignment film 16 is formed on the entire surface of the substrate is prepared. The process flow diagram 2 will be described. As shown in the step (1) of FIG. 2, the rubbing device 48 shown in FIG.
The TFT array substrate 10 is transported and placed on the stage 40. At this time, the stage 40 and the rubbing roller 41 are sufficiently separated.

Next, as shown in step (2), the stage 40 is raised to a predetermined position so that the substrate 10 and the rubbing roller 41 are in contact with each other. At this time, the rubbing roller 4
Numeral 1 is located in the detection area 101 of the substrate 10, and one end of the substrate 1 is a rubbing processing start side.

Next, as shown in step (3), the torque value of the rotating motor of the rubbing roller in the detection area 101 is measured by the torque detection circuit 42. The stage position is detected by the position detection circuit 43.

Next, as shown in steps (4) and (5), the data of the torque value and the stage position in the detection area 101 are input to the computer 44, and whether the torque value matches the predetermined torque value range. Is determined.

If the computer 44 determines that the torque value is within the predetermined torque value range, the control circuit 45 activates the board surface direction moving motor 47, and the stage is moved at the predetermined speed as shown in step (6). It is moved in a direction parallel to the substrate surface (the direction indicated by arrow B in FIG. 1). The movement is performed in one direction from one end to the other end of the substrate, as shown by the arrow in FIG. 6, whereby a rubbing process is performed on the alignment film.

Next, when the rubbing process is completed, (7)
As shown in the process, the stage is lowered, and the substrate subjected to the rubbing process is carried out of the stage 40 as shown in the process (8).

On the other hand, if it is determined in the step (5) that the torque value does not conform to the predetermined torque value range, the vertical movement motor 46 is operated by the control circuit 45 based on the measured torque value and data on the stage position. (9) The stage is raised or lowered as shown in the step. Then, returning to the step (3), the torque value is measured. Steps (3), (4), (5), and (9) are repeated in this order until the torque value falls within the predetermined torque value range.

Here, in addition to the above configuration, a mechanism for rotating the stage may be provided. By rotating the stage, a desired rubbing direction can be provided to the substrate, and the process in this case will be described with reference to FIG. The steps (1) to (5) shown in FIG. 3 are the same as the steps (1) to (5) shown in the above-mentioned step flow chart 2, so that the description is omitted here, and the steps from the step (6) onward are performed. explain.

In the step (6), the stage position d in the case where the torque value conforms to the predetermined torque value range is recorded in the computer 44. Here, by recording the stage position d, the distance between the substrate and the rubbing roller is indirectly recorded. Next, in step (7), the stage is once lowered to a predetermined position where the rubbing roller and the substrate do not come into contact with each other.

Next, in step (8), the stage is rotated by a predetermined angle in the plane of the stage. Thereby, the moving direction of the rubbing roller with respect to the substrate is set.

Next, in step (9), the stage is raised to the position d where the stage was recorded.

Next, as shown in step (10), the stage is moved at a predetermined speed in a direction parallel to the substrate surface (arrow B in FIG. 1).
In the direction indicated by. Thereby, a rubbing process is performed on the alignment film.

Next, when the rubbing process is completed, (1)
1) As shown in the step, the stage is lowered, and (12)
The substrate rubbed as shown in the process is the stage 4
It is carried out from 0. On the other hand, in step (5), when it is determined that the torque value is not matched with the predetermined torque value range, the same process flow as that in FIG. 2 is repeated.

A series of operations relating to these rubbings is as follows.
This is performed for each substrate. In the present embodiment, since the rotation torque can be set to a predetermined range for each different substrate, even when processing a plurality of liquid crystal device substrates having a thickness variation, for example, always a constant rotation torque value, that is, The rubbing treatment of each substrate can be performed at a rubbing pressure. As a result, it is possible to obtain a liquid crystal device in which rubbing intensity does not vary between substrates and display quality is always stable. In addition, since the torque value is detected at one end of the substrate that does not require rubbing processing due to the product configuration, the rubbing processing in the display area is performed at a desired torque value based on the detection of the torque value. Processing can be performed in a continuous operation, and the production efficiency is good.

The substrate to be subjected to the rubbing treatment at the time of rubbing may be a multi-panel substrate on which a plurality of substrates for a liquid crystal device can be formed from one substrate, or one substrate may be used for one liquid crystal device. It may be a single piece that can be used to remove the substrate.

The liquid crystal device that has been subjected to the rubbing method described above has a good display characteristic because of the proper rubbing treatment, and is particularly effective when applied to a projection type display device in which uneven liquid crystal alignment greatly affects the display characteristic. Is exhibited.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a rubbing device according to an embodiment.

FIG. 2 is a flowchart illustrating a rubbing method according to the embodiment.

FIG. 3 is a flowchart illustrating a rubbing method according to another embodiment.

FIG. 4 is an equivalent circuit diagram in a display switching element region of the liquid crystal device.

FIG. 5 is a longitudinal sectional view of the liquid crystal device.

FIG. 6 is a schematic perspective view of a TFT array substrate.

[Explanation of symbols]

 16, 22 ... alignment film 10 ... TFT array substrate 20 ... counter substrate 31 ... liquid crystal device 40 ... stage 41 ... rubbing roller 42 ... torque detection circuit 43 ... position detection circuit 44 ... computer 45 ... control circuit 46 ... vertical movement motor 47 ... Substrate surface direction movement motor 48 rubbing device 100 active region 101 detection region 104, 105 peripheral drive circuit region

Claims (9)

[Claims] 1. A substrate having an alignment film formed on one surface thereof,
A mounting table on which the alignment film is mounted, a rubbing roller that is in contact with the substrate and moves from one end of the substrate toward the other end to perform a rubbing process on the alignment film, and one end of the substrate A torque detection mechanism that detects a rotation torque of the rubbing roller in the unit, and a movement mechanism that moves the rubbing roller or the mounting table so that the rotation torque is within a predetermined range based on the detection result. Rubbing equipment. (A) detecting a rotational torque value of a rubbing roller disposed in contact with one end of a liquid crystal device substrate having an alignment film; and (b) detecting the rotational torque value of the substrate by using the rotational torque value. Controlling the distance to the rubbing roller; (c) repeating the steps (a) and (b) until the rotational torque value falls within a predetermined range; and (d) controlling the rotational torque value to a predetermined value. The rubbing roller relatively moves from one end to the other end of the substrate while maintaining the distance when the range of the liquid crystal device is reached. Rubbing method. 3. In the step (d), the distance when the rotational torque value falls within a predetermined range is recorded, and after the moving direction of the rubbing roller with respect to the substrate is set, the distance is maintained. 3. The method according to claim 2, wherein the rubbing roller relatively moves. 4. The rubbing of the liquid crystal device substrate according to claim 2, wherein the liquid crystal device substrate has an active area and a detection area for detecting the rotational torque. Method. 5. The method according to claim 4, wherein the active area includes a display pixel area and a peripheral driving circuit area for controlling display of the display pixel area. 6. The method for rubbing a substrate for a liquid crystal device according to claim 4, wherein the detection area is formed at an end of the substrate for a liquid crystal device. 7. The liquid crystal device substrate according to claim 2, wherein the steps (a) to (d) are performed for different liquid crystal device substrates. Rubbing method. 8. A substrate for a liquid crystal device, which is manufactured by the method for rubbing a substrate for a liquid crystal device according to claim 2. Description: 9. A liquid crystal device using the substrate for a liquid crystal device according to claim 8.