JPH10187064A - Manufacture of liquid crystal display element, and manufacturing device used for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a liquid crystal display element that has none of defective image display such as display irregularity, color irregularity, etc., due to variance of substrate interval in screen. SOLUTION: Negative charges that a spacer 1 has, while the distribution is controlled in the parallel direction to an electric field produced by a linear electrode 10, i.e., in the horizontal direction, are fallen and dispersed over a substrate 13 in uniform distribution. At this time, control of a dispersing state of the spacer 1 can be conducted by adjusting the values (i.e., potential) of voltages applied individually to plural linear electrodes 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a liquid crystal display element and a manufacturing apparatus used for the same, and more particularly to a manufacturing method and a manufacturing apparatus for uniformly dispersing a spacer material.

[0002]

2. Description of the Related Art In recent years, liquid crystal display elements have been used in various fields as display devices for television or OA, taking advantage of their features of light weight and low power consumption.

[0003] A liquid crystal display element is composed of two substrates, each of which is opposed to each other with a gap therebetween, and in which mutually orthogonal electrode groups are provided, and a liquid crystal layer of a liquid crystal composition sandwiched between the two substrates. There are a simple matrix type in which the main part is formed, and an active matrix type in which a switching element for controlling writing of a signal voltage is provided for each display pixel.

In all liquid crystal display elements, spacers are arranged as uniformly as possible between substrates in order to maintain a constant electrode substrate spacing.

Conventionally, in a process of disposing a spacer material between substrates, a wet disposition method or a dry disposition method has been used as a method of dispersing the spacer material.

[0006] The wet spraying method is the most widely used method, in which a spacer material is uniformly dispersed in a dispersion solvent such as freon, and is sprayed from a spray gun (nozzle) together with compressed air on a substrate constituting a liquid crystal display panel. Spray. The solvent is adjusted so as to be completely dried in a range until it reaches the substrate.

[0007] In the case of an active matrix type liquid crystal display device, it is common to spray a spacer material on the opposing substrate.

On the other hand, a dry spraying method is disclosed in, for example,
As disclosed in JP-A-107222 and JP-A-1-225919, a method of spraying a spacer material without using a dispersion solvent as described above.

[0009]

When monochrome display or gradation display is performed on a liquid crystal display element, unevenness in the arrangement of the spacer material, which has not been a problem in the past, is due to the increase in the definition of the liquid crystal display element and the increase in the number of pixels. Has become a major problem.

In particular, in a liquid crystal display element, even a slight change in the distance between a pair of substrates facing each other causes a change in threshold voltage, a lighting state, and a remarkable change in screen color due to an interference phenomenon, resulting in display quality. (Uniformity within the screen) is significantly impaired.

For this reason, it is required that the variation of the substrate interval within the screen be maintained at a high accuracy of ± 0.05 μm or less.

In order to realize this, it has been found from recent research that it is necessary to control the distribution density of the spacer material within ± 5 pieces / mm ² .

However, in the wet spraying method, even though the spacer material can be dispersed uniformly and without aggregation in the dispersion solvent, the droplet is large in the stage of spraying the spacer material onto the substrate, so that it is included in one droplet. Due to the large number of spacer materials, the spacer materials aggregate during the spraying and form aggregates, which are then placed on the substrate, causing variations in the cell gap, which significantly reduces the display quality of the liquid crystal display device. There was a problem of letting it.

In addition, in this wet spraying method, an organic solvent is generally used as a solvent, but the working atmosphere in which the organic solvent is used has a very bad influence on the human body of the workers, which may cause even a pollution problem. There is also.

[0015] On the other hand, in the dry spraying method, static electricity is generated in the spacer material itself due to collision or friction between the spacer materials, and the charged spacer materials are aggregated to form a cluster and are arranged on the substrate. There has been a problem that the cell gap varies.

As a measure to solve this problem, a dry spraying method using an ionized air flow has been proposed. This method can reduce the aggregation of the spacer material to some extent, however, the direction of the air flow can be reduced. And it is difficult to control the dispersibility, and it is far from keeping the distribution density within ± 5 pieces / mm ² , so that the substrate spacing is ± 0.05 μm.
It was practically very difficult to keep it within.

The present invention has been made to solve such a problem, and an object of the present invention is to solve the problem that the spacer materials are prevented from agglomerating into a cluster and are uniformly arranged on the substrate. It is an object of the present invention to realize a liquid crystal display element having excellent image display performance without image display defects such as display unevenness or color unevenness due to in-screen variations in substrate spacing.

[0018]

According to a method of manufacturing a liquid crystal display element of the present invention, a spacer of fine granular powder or fine rod powder for maintaining a cell gap is sprayed on a substrate provided with an image display electrode. A spacer dispersing step, a step of disposing a substrate provided with an image display electrode on the substrate while maintaining a gap with the spacer, and enclosing a liquid crystal layer in a gap between the substrates and sealing the periphery of both substrates. Stopping the step of dispersing the spacers on the substrate, by applying an electric field substantially perpendicular to the direction in which the spacers fall on the spacers. A step of spraying the spacer on the substrate while controlling a spraying state.

A spacer dispersing step of dispersing a fine-grained powder or a fine rod-shaped powder spacer for maintaining a cell gap on a substrate provided with an image display electrode from a vertical upper side to a lower side; A liquid crystal comprising: a step of disposing a substrate provided with electrodes for use in opposition to the substrate while maintaining a gap with the spacer; and a step of enclosing a liquid crystal layer in a gap between the substrates and sealing the periphery of the two substrates. In the method for manufacturing a display element, when the spacer is sprayed on the substrate,
A voltage is applied to a plurality of linear electrodes stretched substantially parallel to the falling direction of the spacer to generate an electric field substantially perpendicular to the falling direction of the spacer, and the electric field acts on the spacer. And distributing the spacers on the substrate while controlling the horizontal distribution of the spacers.

Further, in the apparatus for manufacturing a liquid crystal display element according to the present invention, there is provided a chamber for accommodating a substrate provided with an electrode for image display, and a spacer for charging a fine-grained powder or fine-rod-shaped powder for maintaining a cell gap. A charging means, a spacer spraying means for spraying the charged spacer on the substrate in the chamber vertically downward from above, and a dropping direction of the spacer when the spacer is sprayed on the substrate. Electric field generating means for generating an electric field in a substantially vertical direction, and applying the electric field to the spacer to spray the spacer on the substrate while controlling the state of the spacer in the horizontal direction. Features.

A chamber for accommodating a substrate provided with an image display electrode; a spacer charging means for charging a fine-grained powder or a fine bar-shaped powder spacer for maintaining a cell gap; And a plurality of lines extending substantially parallel to a drop direction of the spacers when the spacers are scattered on the substrate. A voltage is applied to generate an electric field in a direction substantially perpendicular to the falling direction of the spacer, and the electric field is applied to the spacer to control a horizontal spraying state of the spacer. And a linear electrode for spraying a spacer on the substrate.

A plurality of the linear electrodes and the voltage applied thereto are arranged, for example, so as to surround the substrate placed in the chamber, and a negative voltage is applied to the linear electrodes to apply each of the linear electrodes. While forming an electric field which spreads concentrically in the horizontal direction as a central axis, the spacer is charged negatively just before spraying and is ejected from spacer spraying means such as a jet nozzle, and the negative charge of the spacer is applied to the linear electrode. The distribution may be controlled in a direction parallel to the electric field, that is, in a horizontal direction by the electric field to be formed, and the electric field may be dropped and dispersed on the substrate.

According to the present invention, the spacers can be uniformly dispersed on the substrate by applying a plurality of electric fields in a direction perpendicular to the direction in which the spacers fall.

That is, for example, a plurality of linear electrodes 402 are arranged in a vertical direction so as to surround the periphery of a substrate 401 placed in a chamber, and a negative voltage is applied to each of the linear electrodes 402 to apply each of the linear electrodes. Each of the negatively charged particles 403 spread concentrically in the horizontal direction about the electrode 402 as a central axis and directed toward the central direction horizontal to the main surface of the substrate 401 as a whole, as shown in FIG. An electric field (electric field) is conceptually formed as shown by the curved surface 404. (Here, in FIG. 4, the xy plane indicates the position (coordinate) in the direction horizontal to the substrate 4, and the z-axis indicates the potential of the electric field generated by the entire linear electrode. The existing negatively charged particles 403 receive a force moving toward the lowest position 405 at the center thereof along the potential slope as shown by the curved surface 404 in the drawing.) On the other hand, the spacer becomes negative before spraying. By charging and spraying from a spacer spraying means such as a spray nozzle, the negative charge of the spacer is uniformly distributed on the substrate while the distribution in the horizontal direction is controlled by the electric field created by the linear electrode. Drops are scattered in distribution.

At this time, the control of the state of dispersing the spacers can be performed, for example, by adjusting the value (that is, the potential) of the voltage applied to each of the plurality of linear electrodes.

Further, as the electric field generating means, for example, a cylindrical electrode whose longitudinal direction is substantially parallel to the falling direction of the spacer can be used in addition to the linear electrode as described above.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a method for manufacturing a liquid crystal display device according to the present invention and a manufacturing apparatus used therefor will be described in detail with reference to the drawings.

FIG. 1 is a view showing an outline of the structure of a device for manufacturing a liquid crystal display element according to the present invention.

The spacer 1 in a dry state (one having an average particle size of about φ6 μm as an example in the present embodiment) is stored in the automatic feeder 2.

The amount of the spacer to be supplied to the automatic feeder 2 includes the type and size of the spacer used for one application, the substrate area of the liquid crystal display element to be manufactured, and the type of the liquid crystal display element. Generally, about 15 to 30 mg is used as a single dose.

The automatic supply device 2 is supplied with an injection gas such as dry clean air or nitrogen gas at a predetermined pressure from an external supply device (not shown) through a gas supply port 3. The spacer 1 is sent to the spray gun 5 through the transport pipe 4 together with the spray gas.
Is ejected from the nozzle 6 at the tip of the nozzle.

At this time, a voltage is applied to the spray gun 5 from the applied voltage generator 8 via the wiring 7 and is maintained at a constant potential. Therefore, when the spacer 1 passes through the spray gun 5, the spacer 1 becomes a negative potential. Charges. The applied voltage generator 8 also applies a voltage to the automatic supply 2 via the wiring 9, and also charges the spacer 1 housed in the automatic supply 2.

The linear electrode 10 is used as an electric field generating means.
Are arranged so as to surround the periphery of the substrate 13 mounted on the stage 12 in the chamber 11. A negative voltage is applied to the linear electrode 10 from the applied voltage generator 8 via the wiring 14 to form an electric field that extends concentrically in the horizontal direction with the linear electrode 10 as a central axis.

On the other hand, as described above, the spacer 1
Is charged negatively before spraying and sprayed from the nozzle 6 of the spray gun 5 so that the negative charge of the spacer 1 is reduced to the linear electrode 10.
While the distribution in the direction parallel to the electric field, that is, in the horizontal direction, is controlled by the electric field generated by the above, the liquid crystal is dropped and dispersed on the substrate 13 in a uniform distribution.

At this time, the state of the spacers being scattered can be controlled by adjusting the value (that is, the potential) of the voltage applied to each of the plurality of linear electrodes 10.

That is, for example, as shown conceptually in FIG. 2, when the state of distribution of the spacers 1 is not uniform, the linear shape closest to the portion where the distribution of the spacers 1 is small (the portion with the distribution density 75 at the lower right in the figure). Voltage (value) applied to electrodes 10a and 10b
Are set higher than the other surrounding linear electrodes 10c, d, e,..., So that the spraying state can be controlled to be substantially uniform as shown in FIG.

Here, if the number of the linear electrodes 10 is too small, the valley of the electric field potential between adjacent linear electrodes 10 becomes large, and the distribution of the spacers at that portion becomes large. This is not preferable because the probability of occurrence of bias increases. On the other hand, if the number of the linear electrodes 10 is too small, the intensity of the electric field as a whole, that is, the inclination of the electric field potential becomes too strong, and there is a high probability that the dispersed state of the spacer is largely biased toward the substrate center. Is not preferred. Therefore, the preferred number and arrangement of the linear electrodes 10 are determined by the linear electrodes 1
In general, the number and arrangement of the spacers 1 are at least uniformly distributed on the substrate 13, although they vary depending on conditions such as the thickness of 0, the type of gas in the chamber 11, and the value of the applied voltage. It is needless to say that setting is desirable. For example, in the present embodiment, the linear electrode 1
0, 12 copper or SUS wires each having a diameter of 3 mm are arranged at a pitch of 20 cm so as to evenly surround the periphery of the substrate 13.
Was applied with a negative constant voltage of about 3 KV. A voltage of -70 KV was applied to the spacer 1 before spraying.

As described above, according to the present invention, since the dry spraying method in which the spacers are sprayed without using an organic solvent is employed, it is possible to eliminate the occurrence of pollution caused by the use of the organic solvent. . According to the present invention, since the spacers can be evenly spread on the substrate, highly accurate and uniform cell gap control can be realized.

As the electric field generating means according to the present invention, in addition to the linear electrode 10 as described above, for example, a cylindrical shape (a) whose longitudinal direction is substantially parallel to the falling direction of the spacer as shown in FIG. ) Or an electrode shaped like a square frame (b).

[0040]

As described above, according to the present invention, according to the present invention, it is possible to solve the problem that the spacer materials are prevented from agglomerating into a conglomerate and can be uniformly disposed on the substrate. In addition, it is possible to realize a liquid crystal display device having excellent image display performance without image display defects such as display unevenness and color unevenness due to in-screen variations in substrate spacing.

[Brief description of the drawings]

FIG. 1 is a diagram showing an outline of the structure of a liquid crystal display element manufacturing apparatus according to the present invention.

FIG. 2 is a diagram showing an example of a method of controlling a spacer scattering state in the liquid crystal display element manufacturing apparatus according to the present invention.

FIG. 3 shows an electrode having a cylindrical shape (a) or a rectangular frame shape (b) substantially parallel to the direction in which a spacer is dropped, which is applicable to the apparatus for manufacturing a liquid crystal display element according to the present invention. FIG.

FIG. 4 is a diagram conceptually showing a potential distribution of an entire electric field formed by a linear electrode according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Spacer 2 ... Automatic supply device 3 ... Gas supply port 4 ... Conveying pipe 5 ... Injection gun 6 ... Nozzle 7 ... Wiring 8 ... Applied voltage generator 9 ...... Wiring 10 ... Linear electrode 11 ... Chamber 12 ... Stage 13 ... Substrate 14 ... Wiring

Claims (4)

[Claims] A spacer dispersing step of dispersing a fine-grained powder or a fine rod-shaped powder spacer for maintaining a cell gap on a substrate provided with an image display electrode; A method for manufacturing a liquid crystal display element, comprising: a step of disposing the liquid crystal layer opposite to the substrate while maintaining a gap with the spacer; and a step of enclosing a liquid crystal layer in a gap between the substrates and sealing a periphery of the two substrates. When the spacers are sprayed on the substrate, an electric field substantially perpendicular to the drop direction of the spacers is applied to the spacers, and the spacers are sprayed on the substrate while controlling the spraying state of the spacers. A method for manufacturing a liquid crystal display device, comprising the steps of: 2. A spacer dispersing step of dispersing a fine-grained powder or a fine rod-shaped powder spacer for maintaining a cell gap on a substrate provided with an image display electrode from vertically upward to downward. A step of disposing a substrate provided with electrodes for facing the substrate while maintaining a gap with the spacer;
Enclosing a liquid crystal layer in a gap between the substrates and sealing the periphery of the two substrates, the method comprising the steps of: A voltage is applied to a plurality of linear electrodes stretched substantially in parallel to generate an electric field in a direction substantially perpendicular to the falling direction of the spacer, and the electric field is applied to the spacer to cause a horizontal direction of the spacer. A step of spraying the spacers on the substrate while controlling the distribution of the liquid crystal display element. A chamber for accommodating a substrate having an electrode for image display; a spacer charging means for charging a fine-grained powder or a fine rod-shaped powder spacer for maintaining a cell gap; A spacer spraying means for spraying the substrate downward from above in the vertical direction, and generating an electric field substantially perpendicular to the falling direction of the spacer when spraying the spacer on the substrate; An apparatus for manufacturing a liquid crystal display device, comprising: an electric field generating means for spraying the spacer on the substrate while controlling a horizontal spray state of the spacer by applying an electric field to the spacer. 4. A chamber for accommodating a substrate provided with an electrode for image display, a spacer charging means for charging a fine-grained powder or a fine rod-shaped powder spacer for maintaining a cell gap; A spacer spraying means for spraying the substrate downward from above in the vertical direction, and a plurality of lines stretched substantially in parallel to a falling direction of the spacer when spraying the spacer on the substrate. A voltage is applied to generate an electric field in a direction substantially perpendicular to the falling direction of the spacer, and the electric field is applied to the spacer to control a horizontal spraying state of the spacer. Linear electrodes for dispersing spacers on the substrate,
An apparatus for manufacturing a liquid crystal display element, comprising: