JP2892558B2 - Rubbing treatment apparatus and liquid crystal display element manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus used for forming a molecular alignment film as one step of manufacturing a liquid crystal display device.
More specifically, the present invention relates to a rubbing apparatus for stabilizing the orientation of parallel alignment of liquid crystal molecules and a method for manufacturing a liquid crystal display element.

[0002]

2. Description of the Related Art In a manufacturing process of a liquid crystal display device, the performance and quality of the liquid crystal display device largely depend on the formation of an alignment film for alignment of liquid crystal molecules. A rubbing method is one method of an alignment treatment for forming an alignment film, and a rubbing treatment is performed by rubbing (rubbing) an alignment film such as polyimide.

In a conventional rubbing treatment apparatus, a rubbing roller having a pile of cloth or the like wound on a peripheral surface thereof is driven to rotate, and the rubbing roller and a substrate coated with an alignment film material are relatively moved. The rubbing treatment is performed by rubbing the substrate.

At this time, the gap between the rubbing roller and the substrate is kept constant, and a pile of cloth or the like wound around the peripheral surface of the rubbing roller rubs on the substrate while maintaining an appropriate rubbing pressure. By the rubbing treatment, the polymers of the alignment film are aligned in a certain direction, and the liquid crystal molecules are aligned in a regular manner.

[0005]

In the rubbing treatment, the rubbing stability depends on the rubbing pressure, that is, the distance (gap value) between the rubbing roller and the substrate. For example, if the gap value during the rubbing process is excessively larger than the gap value at which a proper rubbing pressure can be obtained, the pile hits the substrate weakly, the rubbing pressure decreases, and a stable alignment of liquid crystal molecules cannot be obtained. . Conversely, if the gap value is too small, the rubbing pressure will be too large, and the pile will damage the alignment film, causing display failure.

In the conventional rubbing apparatus, the rubbing process is continuously performed after the worker adjusts the gap value before the rubbing process, and the gap value is not adjusted again each time. Therefore, since the gap value initially set does not change, the rubbing pressure fluctuates due to the variation in the thickness of the substrate, and stable rubbing processing cannot be performed. Further, an appropriate gap value may be different depending on the type of the alignment film material applied on the substrate, and in such a case, the gap value must be adjusted, and the work efficiency becomes poor.

SUMMARY OF THE INVENTION In view of the above problems, the present invention can adjust a proper gap value for each plate-like body such as a substrate, and can always perform a stable rubbing process. An object of the present invention is to provide a method for manufacturing a liquid crystal display element capable of performing a rubbing treatment.

[0008]

According to the present invention, there is provided a rubbing apparatus for performing a rubbing treatment on a surface of a plate-like body, comprising: means for rubbing the surface of the plate-like body in a fixed direction; Displacement driving means for driving the means relatively close to / separate from each other, and measuring means for measuring the position of the surface of the plate in the vertical direction before the rubbing process for each plate, and outputting the measured value And, a memory for storing a predetermined distance between the rubbing means and the plate-like body, and in response to an output from the measuring means, the measured value measured by the measuring means and the memory A rubbing processing device comprising: a calculating unit that calculates based on the stored distance and outputs a driving signal corresponding to the calculation result to the displacement driving unit. Further, the present invention provides a method for manufacturing a liquid crystal display device, in which a substrate coated with an alignment film material is rubbed and subjected to an alignment treatment, wherein before the rubbing is performed, the thickness of the substrate is measured for each substrate, and according to the measurement result. Rubbing with a constant distance between the rubbing means and the substrate.

[0009]

According to the present invention, the position in the vertical direction of the surface of the plate to be subjected to the rubbing treatment is measured by the measuring means, and the measured value is converted into, for example, an electric signal and outputted to the control means. The control means, in response to the output from the measurement means, calculates based on the measured value measured by the measurement means and a predetermined distance stored in the memory, and generates a drive signal corresponding to the calculation result. The rubbing pressure is output to the displacement driving means, and the distance (gap value) between the rubbing means and the plate-like body is feedback-controlled to keep the rubbing pressure constant.

[0010]

FIG. 1 is a block diagram showing an electrical configuration of a rubbing apparatus 1 according to one embodiment of the present invention. The rubbing processing device 1 includes a central processing unit (CP) configured to include, for example, a microprocessor as control means.
U) 2, and the central processing unit 2 is connected to a read-only memory (ROM) 3 in which programs for controlling various operations of the rubbing processing device 1 are stored. The storage area of the read-only memory 3 stores a gap value measured in advance so that an appropriate rubbing pressure can be obtained. The central processing unit 2 also includes a switch 4 for starting / ending the operation of the rubbing processing unit 1 and a position of a substrate or the like in a vertical direction, and converts the measured value into an electric signal and outputs the signal. Measuring means 5 for storing the position of the substrate measured by the measuring means 5, the distance between the rubbing roller 27 and the substrate described later, and the distance between the rubbing roller 27 and the rubbing stage 25 described later. A random access memory (RAM) 6 is connected.

The central processing unit 2 further includes a roller rotation drive mechanism 7 for rotating and driving the rubbing roller 27, a stage base horizontal movement mechanism 8 for horizontally moving a stage base 10 described later, and a rubbing mechanism. Stage 25
And a rubbing stage elevating drive mechanism 9 serving as a displacement drive means for driving the rubbing roller 27 toward and away from the rubbing roller 27. These mechanisms 7, 8, 9
Are respectively controlled by the central processing unit 2 according to the program stored in the.

FIG. 2 shows a rubbing stage elevating drive mechanism 9.
FIG. 3 is a side view of the stage table 10 having the above-described configuration. Stage base 1 which is a rectangular parallelepiped casing
A servo motor 11 is provided inside the motor shaft 0, and a drive shaft 12 is connected to a shaft of the servo motor 11 in an upward direction in FIG. Further, a plurality of (three in this embodiment) driven shafts 13, 14, 15 are dispersedly erected on the upper surface 10a of the stage base 10 in the upward direction in FIG. Locking grooves 12a,
13a, 14a, and 15a are formed, and an endless belt 16 is wound around each of the locking grooves 12a to 15a.
On both sides of each shaft 12-15, a holding shaft 17,1 for pressing the endless belt 16 against the groove 12a-15a.
8, 19, 20, 21, 22, 23, and 24 are erected, respectively. Accordingly, when the drive shaft 12 is rotated by the drive of the servomotor 11, the driven shafts 13 to 15 are rotated in the same direction as the drive shaft 12 via the endless belt 16.

In FIG. 3, male screws 12b, 13b, 14b, and 15b (not shown) are threaded on the upper portions of the shafts 12 to 15, and the lower surface 25a of the rubbing stage 25 is provided on the lower surface 25a. At the position corresponding to
female screws 25b, 25c, 25d to be screwed to b to 15b,
25e (not shown) is threaded. Servo motor 1
By changing the polarity of the voltage applied to the rubbing stage 25, the rotation direction of the servomotor 11 is reversed.
As shown by an arrow A, it can be driven to move toward / away from the stage table 10 (vertical direction in FIG. 3). In FIG. 3, a plate-shaped substrate is placed on the upper surface 25 f of the rubbing stage 25 in the upward direction. The substrate is fixed by suction means (not shown) formed on the rubbing stage 25.

FIG. 4 is a perspective view showing the entire structure of the rubbing apparatus 1 of the present embodiment. In FIG. 4, a substrate 26 coated with an alignment film material is fixed to the upper surface 25f of the rubbing stage 25, and the stage base 10 is moved in the direction of the arrow B (rightward) by a conveyor, which is a stage base horizontal moving mechanism 8 (not shown). Go to). A pair of roller supports 28 and 29 for supporting the rubbing roller 27 are fixed in the direction in which the stage 10 moves. A pile of, for example, cloth is wound around the rubbing roller 27, and bearing holes 28a, 29a formed in the respective roller supports 28, 29 are formed.
(Not shown) support shafts 27a and 27 of the rubbing roller 27
b (not shown) is inserted and pivotally supported. The rubbing roller 27 includes a roller rotation drive mechanism 7 (not shown).
Thus, the exposed surface 26a of the substrate 26 is rubbed in a certain direction by rotating in the direction of arrow C.

In FIG. 4, a support member 30 protruding from the upper end portion 28b of one of the roller abutments 28 and protruding toward the stage table 10 is provided, and the tip of the support member 30 is a measuring means. Plunger type electric micro gauge 3
1 is suspended and connected on the transport path of the stage table 10. The electric microgauge 31 is an electric micrometer using a differential transformer, converts the linear displacement (vertical direction in FIG. 4) of the tracing stylus 31a at the tip into a voltage, and further converts the analog signal thereof. The signal is converted into a digital signal and output to the central processing unit 2.

FIG. 5 is a flowchart showing the operation of the rubbing processing device 1. First, in step a1, when the switch 4 is turned on, a drive current is supplied to a motor for rotating the rubbing roller 27 at a constant speed in accordance with the program stored in the read only memory 3, and the rubbing roller 27 is turned on as shown in FIG. It is rotationally driven in the direction of arrow C. next,
In step a2, the stage base 10 is moved in the direction approaching the roller supports 28 and 29 (the direction of the arrow B in FIGS. 4 and 6) by the conveyor (not shown) which is the stage base horizontal movement mechanism 8. In step a3, the stage base 10 is further moved, and as shown in FIG. 6, the tip of the measuring element 31a of the electric micro gauge 31 is brought into contact with the peripheral edge of the surface 26a of the substrate 26. The linear displacement 31a, that is, the position of the surface 26a of the substrate 26 in the vertical direction is converted into an electric quantity and output to the central processing unit 2. At this point, the position of the rubbing stage 25 in the vertical direction is at a predetermined reference position (for example, the lowest position).

In the storage area of the RAM 6, the tracing stylus 3 when the substrate 26 is not placed on the rubbing stage 25 is provided.
1a is stored in advance, and the thickness of the substrate 26 is reduced by subtracting the linear displacement when the substrate 26 is not mounted from the linear displacement when the substrate 26 is mounted. You can ask. The central processing unit 2 stores the thickness of the substrate 26 in the storage area of the RAM 6.

At step a4, it is determined whether or not the rubbing stage 25 should be lowered based on the thickness of the substrate 26 stored in the RAM 6. That is, the vertical distance (M) between the rubbing stage 25 and the rubbing roller 27 measured and obtained in advance is stored in the storage area of the RAM 6, and an appropriate value is stored in the storage area of the ROM 3. A predetermined gap value (G) is stored so as to obtain a rubbing pressure, and the displacement amount (S) of the rubbing stage 25 to be displaced upward or downward is as follows, where D is the thickness of the substrate 26. It is determined by the formula.

[0019]

S = M−G−D At this time, if the displacement (S) is a negative value, the process proceeds to step a5, and if not, the process proceeds to step a6. At step a6, contrary to step a4, it is determined whether the displacement amount (S) is a positive value. If so, the process proceeds to step a7, and if not, the process proceeds to step a8. . In step a5, a driving current corresponding to the displacement amount (S) obtained in step a4 is supplied to the servo motor 11 to rotate the drive shaft 12, thereby moving the rubbing stage 25 to a high level of the displacement amount (S). Lower by just a minute.

In step a7, the drive shaft 12 is rotated in the direction opposite to that in step a6, and the rubbing stage 2 is rotated.
5 is raised by the height of the displacement obtained in step a4. In step a8, the rubbing stage 2 is moved by moving the stage base 10 further in the direction of arrow B.
The surface 26a of the substrate 26 on the surface 5 comes into contact with the pile wound around the rubbing roller 27, and the rubbing process is performed. After the rubbing treatment, the stage table 10 is moved to the roller supports 28 and 29.
Then, it moves in the direction away from (rightward in FIG. 6), and the operation ends.

After the rubbing process, the rubbing stage 25 is programmed to move by the height of the ascending / descending and automatically return to the original position (for example, the lowest position). The rubbing process is performed on the next new substrate in the same manner. However, if the gap value must be changed because the type of the alignment film material applied on the substrate is different, for example, the ROM 3 may be used. The switch 4 is operated in order to change the gap value to an appropriate gap value previously stored in the storage area and corresponding to the type of the alignment film material.

FIG. 7 shows a rubbing apparatus 1 of the above embodiment.
9 is a graph plotting the relationship between the thickness of a substrate and the measurement result of a load current value of a rubbing roller during a rubbing process for a conventional rubbing apparatus. In FIG. 7, a plot of "●" indicates a result obtained by the rubbing apparatus 1 of the present embodiment, and a plot of "○" indicates a result obtained by the conventional rubbing apparatus. Here, the load current value is considered to be proportional to the rubbing pressure. In FIG. 7, in the plot with the reference symbol P1, the rubbing pressure is too low, and the rubbing is insufficient.
In the plots marked with, scratches were generated in the alignment film because the rubbing pressure was too high. As is clear from FIG. 7, by adjusting the gap value to an appropriate value for each substrate, a constant load current value, that is, a stable rubbing pressure can always be obtained.

As described above, according to this embodiment, there is no need for the operator to adjust the gap value to an appropriate value for each substrate, and the feedback control is automatically performed, so that the work efficiency is high. Further, the rubbing pressure is appropriately maintained for each substrate, and for example, it is possible to prevent the alignment film from being damaged, which may cause display failure.
Furthermore, if the appropriate gap value is the same as the condition at the time of the rubbing treatment, it is necessary to adjust the gap value each time these changes are made, for example, even when the alignment film material and the type of pile are changed. Absent.

In the above embodiment, the rubbing stage 2
The displacement amount (S) of No. 5 is calculated by obtaining the thickness (D) of the substrate 26, but only the gap value (G) that provides an appropriate rubbing pressure is stored in the storage area of the ROM 3, The vertical position of the surface 26a of the substrate 26 before the rubbing treatment is measured by the micro gauge 31, and the measured value (the linear displacement of the tracing stylus 31a) is the gap value (G).
The rubbing stage 25 may be moved up and down by a height corresponding to the difference between the two displacement amounts so that the displacement amount corresponds to the displacement amount. In this case, as in the above embodiment, the vertical distance (M) between the rubbing stage 25 and the rubbing roller 27 and the linear displacement amount of the tracing stylus 31a when the substrate is not placed on the rubbing stage 25. Need to be measured in advance and stored in the storage area of the RAM 6. Further, it is not necessary to return the rubbing stage 25 to the reference position for each rubbing process, and the measurement by the micro gauge 31 can be performed at an arbitrary position.

In the above embodiment, the thickness is measured once for each substrate 26 using a single electric micro gauge 31. For example, when the substrate 26 is large, a plurality of electric micro gauges 31 are used. May be used to measure the thickness at a plurality of locations on the substrate 26, and the average value may be used as the measured value. There is no particular limitation as long as it converts the measured value into an electric quantity. For example, a dial gauge or the like can be used.

In the above embodiment, the stage 10 is moved. However, the roller supports 28 and 29 may be moved toward the stage 10.
Further, both the stage 10 and the roller supports 28 and 29 may be moved relative to each other. Similarly, the rubbing roller 27 may be driven to move up and down.

[0027]

As described above, according to the present invention, the gap value can be feedback-controlled for each plate-like body and the rubbing pressure can be kept constant, so that it is necessary for the operator himself to adjust the gap value. In addition, a stable rubbing process can be performed, and a liquid crystal display element with high working efficiency and high display quality can be manufactured.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an electrical configuration of a rubbing processing device 1 according to an embodiment of the present invention.

FIG. 2 is a stage table 1 having a stage elevating drive mechanism 9.
0 is a plan view.

FIG. 3 is a side view of FIG. 2;

FIG. 4 is a perspective view showing the entire configuration of the rubbing processing device 1 of the present embodiment.

FIG. 5 is a flowchart showing an operation of the rubbing processing device 1.

FIG. 6 is a side view showing the operation of the rubbing processing device 1.

FIG. 7 is a graph plotting a relationship between a substrate thickness and a load current value of a rubbing roller.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rubbing processing apparatus 2 Central processing unit 3 Read-only memory 5 Measuring means 6 Random access memory 7 Roller rotation drive mechanism 8 Stage base horizontal movement mechanism 9 Rubbing stage elevating drive mechanism 26 Substrate 26a Surface 27 Rubbing roller 31 Electric micro gauge

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-64-54418 (JP, A) JP-A-4-155313 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G02F 1/1337

Claims (2)

(57) [Claims] 1. A rubbing treatment apparatus for performing a rubbing treatment on a surface of a plate-like body, comprising: means for rubbing the surface of the plate-like body in a fixed direction; Displacement driving means for driving the separation displacement, measuring means for measuring the position in the vertical direction of the surface of the plate before each rubbing process for each plate, and outputting the measured value; rubbing means and the plate A memory for storing a predetermined distance between the object and the object, and in response to an output from the measuring means, based on the measured value measured by the measuring means and the distance stored in the memory. A rubbing processing device comprising: a calculating means for calculating and outputting a driving signal corresponding to the calculation result to the displacement driving means. 2. A method of manufacturing a liquid crystal display element, comprising rubbing a substrate coated with an alignment film material and performing an alignment treatment, wherein the thickness of the substrate is measured for each substrate before rubbing.
A method for manufacturing a liquid crystal display element, wherein rubbing is performed with a constant distance between a rubbing unit and the substrate according to the measurement result.