JP2000338502A - Device and method for production of liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make applicable a spacer material with a uniform film thickness. SOLUTION: When columnar spacers are to be formed on the surface of a glass substrate 1, the spacer material 12 is fed at a constant rate of the quantity to a coating head 23 by a feeding part 22 and the spacer material 12 is applied on the glass substrate 1 by the coating head 23. In this process, the gap K between the lower end of the coating head 23 and the surface of the glass substrate 1 can be always kept constant by detecting the gap K between the lower end of the coating head 23 and the surface of the glass substrate 1 by a sensor part 24 and moving the coating head 23 in the perpendicular direction relative to the surface of the glass substrate 1 according to the detected data. Since the spacer material 12 is applied on the glass substrate 1 while the coating head 23 kept in the aforementioned position is moved at a constant speed, any spacer material 12 without being restrictected to a limited number of columnar pacer materials can be applied to uniform thickness with good accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for manufacturing a liquid crystal display, and more particularly to an apparatus for manufacturing a spacer provided between a pair of substrates of a liquid crystal display.
And a manufacturing method of joining a pair of substrates via the spacer.

[0002]

2. Description of the Related Art In general, in a liquid crystal display device, if a liquid crystal layer sealed between a pair of glass substrates has a thickness unevenness, display unevenness occurs and visibility deteriorates. Of the liquid crystal layer must be kept constant by keeping the distance between them uniform. As such a liquid crystal display device,
For example, there is one in which bead-shaped spacers are scattered between a pair of glass substrates, and the scattered bead-shaped spacers maintain a predetermined interval between the pair of glass substrates. However, in this liquid crystal display device, it is necessary to uniformly and uniformly scatter the bead-shaped spacers. In addition to the above, there are problems such as easy occurrence of insufficient pressure resistance.

As a liquid crystal display device which solves such a problem, there has been proposed a liquid crystal display device in which a columnar spacer is formed between a pair of glass substrates, and the pair of glass substrates is maintained at a predetermined distance by the columnar spacer. . FIG. 5 is a diagram showing an example. This liquid crystal display device is of an active type that displays a color image, and includes a pair of transparent glass substrates 1 and 2. The pair of glass substrates 1 and 2 are arranged so as to face up and down.

In this case, transparent pixel electrodes 3 made of ITO or the like are arranged in rows and columns on the opposing surface (the upper surface in FIG. 1) of the lower glass substrate 2. Are formed so as to be electrically connected to the respective pixel electrodes 3. The lower surface of the lower glass substrate 2 has a TFT
A transparent plate 6 provided with a light shielding portion 5 is provided at a location corresponding to 4. Further, a black matrix 7 and a color filter 8 are formed on the opposing surface (the lower surface in the figure) of the upper glass substrate 1. Black matrix 7
Are provided between the pixel electrodes 3 and corresponding to the TFTs 4. The color filter 8 is configured by sequentially arranging red, green, and blue filter portions R, G, and B. Each of these filter portions R, G, and B corresponds to the pixel electrode 3, and each of the filter portions R, G , B are formed on the black matrix 7. On the lower surface of the color filter 8, a transparent common electrode 9 such as ITO is formed.

The pair of glass substrates 1 and 2 are arranged such that an upper common electrode 9 and a lower pixel electrode 3 face each other,
The black matrix 7 and the pixel electrode 3 between them
The columnar spacers 10 are formed at predetermined positions corresponding to the spaces, and are joined by the columnar spacers 10 while maintaining a predetermined interval C therebetween. And a pair of glass substrates 1,
Between the two, the liquid crystal 11 is sealed with a sealing material (not shown). When such a columnar spacer 10 is formed, the upper glass substrate 1 of the pair of upper and lower glass substrates 1 and 2 is turned upside down, and the upper surface (the lower surface in FIG. A spacer material such as a photosensitive resin is applied to the surface of the common electrode 9 formed through the matrix 7 and the color filter 8 (hereinafter referred to as the surface of the glass substrate 1 for convenience of description) by a spin coater. The columnar spacer 10 is formed at a predetermined position corresponding to the black matrix 5 by patterning the spacer material by photolithography.

[0006]

However, in such an apparatus for manufacturing a liquid crystal display device, the columnar spacer 10 is formed by applying a spacer material on the surface of the glass substrate 1 and patterning the same. The height of the columnar spacer 10 is determined by the film thickness when the spacer material is applied, whereby the distance C between the pair of glass substrates 1 and 2 is determined. Therefore, in this manufacturing apparatus, high precision is required when applying the spacer material. However, if the spacer material is applied by the spin coater, as shown in FIGS. 6A and 6B. To
Depending on the spacer material 12 such as a photosensitive resin containing a pigment, the thickness of the central portion of the glass substrate 1 increases, and the thickness of the peripheral portion decreases. In such a case, the height of the columnar spacers 10 becomes non-uniform, and the distance C between the pair of glass substrates 1 and 2 cannot be formed uniformly. Therefore, the spacer material 12 as the columnar spacers 10 is limited. There is a problem that will be done. In particular, spacer material 1
In the method of applying 2 with a spin coater, the spacer material 1
Since most of the materials 2 are blown to the surroundings, there is a problem that the use efficiency of the material is low and the material cost is high.

When such a columnar spacer 10 is used, the end surfaces of the columnar spacers 10 are in surface contact with the opposing surfaces of the pair of glass substrates 1 and 2, and the hardness of the columnar spacer 10 is high. From a pair of glass substrates 1, 2
At the time of bonding, under the normal pressing conditions described later, each columnar spacer 10 hardly deforms, and the spacer material 12
There is also a problem in that the application accuracy of the above becomes the accuracy of the distance between the pair of glass substrates 1 and 2 as it is, and the desired distance C between the glass substrates 1 and 2 cannot be obtained.

For example, when a bead-shaped spacer is used, the spacer diameter is 4.75 ± 0.25 μm and the distribution density is 100 pieces.
/ mm ² , the pressure at the time of pressing and the distance between the glass substrates have the relationship shown in FIG. 7A. The pressure at the time of pressing is 0.23 kgf / cm ² , and the spacer having a large diameter is 4.75 μm. The distance between the glass substrates is approximately the same as the spacer design value of 4.75 μm. On the contrary,
When the columnar spacer 10 is used, the columnar spacer 10
Height (film thickness) is 4.75 ± 0.15 μm and columnar spacer 10
Is 100 μm ² and the dispersion density is 21.5 pieces / mm ² , the pressure during pressing and the distance C between the glass substrates 1 and 2
FIG. 7B shows the relationship shown in FIG. 7B. In order to form the gap C between the glass substrates 1 and 2 at a desired value of 4.75 μm, a pressure at the time of pressing is required to be 1.3 kgf / cm ² . But,
Since the maximum pressure at the time of current production is about 0.7 kgf / cm ² , each columnar spacer 10 is hardly deformed, and the application accuracy of the spacer material 12 becomes the interval accuracy between the glass substrates 1 and 2 as it is. If the cross-sectional area and the dispersion density of the columnar spacer 10 are reduced in order to reduce the pressure at the time of pressing, a problem arises in that the pressure resistance decreases.

An object of the present invention is to provide an apparatus for manufacturing a liquid crystal display device which can apply a spacer material with a uniform film thickness. Another object of the present invention is to provide a method of manufacturing a liquid crystal display device that can reduce the pressure at the time of pressing and can accurately form a desired interval between a pair of substrates.

[0010]

According to the first aspect of the present invention,
Of a pair of transparent substrates in which liquid crystal is sealed, a spacer material is applied to the surface on the opposite side of one of the substrates, and the spacer material is patterned by photolithography, so that the surface of the one substrate is In a manufacturing apparatus of a liquid crystal display device for forming a columnar spacer, a supply unit for supplying the spacer material by a constant amount, and the spacer material supplied by the supply unit is moved at a constant speed to the surface of the one substrate. A coating head for coating is provided, and a detecting means for detecting a distance between a tip of the coating head and the surface of the substrate is provided. According to the present invention, when forming a columnar spacer on the surface of one substrate,
The supply means supplies the spacer material to the coating head by a predetermined amount, and when the supplied spacer material is applied to the surface of the substrate by the coating head, the distance between the tip of the coating head and the surface of the substrate is detected by the detection means. By detecting and moving the coating head relative to the surface of the substrate in the vertical direction based on this detection data, the distance between the tip of the coating head and the surface of the substrate can always be kept constant,
While maintaining this state, the coating head moves at a constant speed to apply the spacer material to the surface of the substrate, so that the spacer material as the columnar spacer is not limited as in the related art, and any kind of spacer material can form a uniform film. Thickness can be applied, and the spacer material does not fly to the periphery unlike a spin coater, so that the material can be used efficiently.

According to a second aspect of the present invention, a spacer material is applied to a surface of one of a pair of transparent substrates in which liquid crystal is sealed, and the spacer material is patterned by photolithography. By forming a columnar spacer on the surface of the one substrate and bonding the pair of substrates via the columnar spacers, the method includes manufacturing the liquid crystal display device by bonding the pair of substrates via the columnar spacer. In this case, the columnar spacers are joined by being pressed at a predetermined temperature while being heated.
According to the present invention, when a pair of substrates are joined via the columnar spacer, the columnar spacer is heated at a predetermined temperature to reduce the elastic modulus of the spacer material and pressurized in this state. Accordingly, the pressing force can be reduced, whereby a pair of substrates can be accurately formed at a desired interval, and the cross-sectional area and the dispersion density of the columnar spacers do not need to be reduced, and the spacers can be formed after pressing. When the material returns to the original elastic modulus, sufficient pressure resistance can be obtained.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of an apparatus and method for manufacturing a liquid crystal display device according to the present invention will be described with reference to FIGS. The liquid crystal display device is shown in FIG.
Has the same configuration as that shown in FIG. 1, the same portions are denoted by the same reference numerals, and description thereof will be omitted. FIG. 1 is a configuration diagram conceptually showing an apparatus for manufacturing a liquid crystal display device. The manufacturing apparatus shown in this figure includes a pair of glass substrates 1 of a liquid crystal display device,
This is an apparatus for applying a spacer material 12 of the columnar spacer 10 to the glass substrate 1 when forming the columnar spacer 10 interposed between the two. That is, this manufacturing apparatus is a die coater, and a stage 21 on which the glass substrate 1 is mounted.
A supply unit 22 for supplying the spacer material 12, a coating head 23 for applying the spacer material 12 supplied by the supply unit 22 to the glass substrate 1 on the stage 21, a lower end of the coating head 23 and the glass substrate And a sensor unit 24 for detecting an interval K with respect to the surface of the sensor 1. A black matrix 7 and a color filter 8 are formed on the upper surface of the glass substrate 1, and a common electrode 9 is formed on the surface of the color filter 8. A spacer material 12 is formed on the surface of the common electrode 9. Is applied.

The supply section 22 is composed of a high-precision pump such as a syringe pump, and is configured to continuously supply the spacer material 12 to the coating head 23 by a constant amount. The coating head 23 is configured to have substantially the same length as the width of the glass substrate 1 (length in the front-back direction on the paper surface of FIG. 1), and is disposed above the glass substrate 1 placed on the stage 21 with a predetermined clearance. In this state, it is configured to move at a constant speed in the arrow X direction shown in FIG.
The sensor unit 24 is a laser sensor, and the coating head 23
The lower end of the coating head 23 and the glass substrate 1 are constantly detected by detecting the height of the glass substrate 1 while moving with the coating head 23.
Is configured to detect a distance K from the surface.

In such a manufacturing apparatus, the supply unit 22 supplies the spacer material 12 to the coating head 23 by a predetermined amount, and the supplied spacer material 12 is supplied to the coating head 23.
When the coating is performed on the glass substrate 1, the sensor unit 24 detects the distance K between the lower end of the coating head 23 and the surface of the glass substrate 1, and based on this detection data,
Is moved in the vertical direction relative to the surface of the glass substrate 1 so that the distance K between the lower end of the coating head 23 and the surface of the glass substrate 1 can be kept constant. Then, while maintaining this state, the coating head 23 moves at a constant speed in the direction of the arrow X shown in FIG. 1 to apply the spacer material 12 to the glass substrate 1, so that the spacer material 12 as the columnar spacer 10 is conventionally removed. There is no limitation, and any spacer material 12 can be applied with a uniform film thickness and high accuracy as shown in FIG. 2, and the spacer material 12 does not fly to the periphery unlike a spin coater. Good use efficiency of materials.

Next, a manufacturing method in which a columnar spacer 10 is formed from the spacer material 12 applied to the glass substrate 1 and the pair of glass substrates 1 and 2 are joined via the columnar spacer 10 will be described. First, the glass substrate 1
After the spacer material 12 is applied to the
Is patterned by photolithography, thereby forming columnar spacers 10 on the surface of the glass substrate 1 in correspondence with the black matrix 7. Thereafter, the pair of glass substrates 1 and 2 are joined via the columnar spacer 10. At this time, the columnar spacers 10 are joined while being heated at a predetermined temperature while being pressed. That is, the columnar spacer 1
When 0 is heated at a predetermined temperature, the elastic coefficient of the spacer material 12 decreases. For example, when the spacer material 12 is a photosensitive resin, the elastic coefficient (Young's modulus) of the spacer material 12 is about 5 × 10 ¹⁰ dyn / cm ² at room temperature as shown in FIG. When heated, the elastic modulus is 1.8 × 10
^It is reduced to about ¹⁰ dyn / cm ² . By applying pressure in this state, the pressure at the time of pressing can be reduced to a pressure that is possible in the current production state.

That is, when the columnar spacer 10 is pressurized at room temperature without heating as in the prior art in order to obtain a desired distance C between the glass substrates 1 and 2, the pressure at the time of pressing is as shown in FIG. As shown in b), about 1.3 kgf / cm ^{2 is} required,
In practice it is difficult. On the other hand, the columnar spacer 10
The same forming conditions (height 4.75 ± 0.15μm, cross-sectional area 100μ)
m ² and a dispersion density of 21.5 pieces / mm ² ), and when these columnar spacers 10 are heated and pressed at about 70 ° C., the elastic modulus is reduced to about 1.8 × 10 ¹⁰ dyn / cm ² . As shown in FIG. 4, the pressure at the time of pressing can be reduced to about 0.5 kgf / cm ^2, which is a pressure that can be achieved in the current production state, so that the pair of glass substrates 1 and 2 can be moved to a desired distance C. It can be formed with high accuracy. In this case, there is no need to reduce the cross-sectional area and dispersion density of the columnar spacer 10,
In addition, by returning the columnar spacer 10 to normal temperature after pressurization, the spacer material 12 has the original elastic modulus (5 × 10 ¹⁰ dyn).
/ cm ² ), so that sufficient pressure resistance can be obtained.

In the above embodiment, a die coater has been described as a manufacturing apparatus. However, the present invention is not limited to this, and may be applied to a spray coater, a curtain coater, and the like. In the above embodiment, the liquid crystal display device includes:
The color liquid crystal display device for displaying a color image has been described. However, the present invention is not limited to this, and can be applied to a monochrome display without using the color filter 8. It can also be applied to liquid crystal display devices of the type.

[0018]

As described above, according to the apparatus for manufacturing a liquid crystal display device according to the first aspect of the present invention, the surface of one of the transparent substrates on which the liquid crystal is sealed is opposed to the other substrate. When the columnar spacer is formed, the spacer material is supplied to the coating head by a constant amount by a supply unit, and when the supplied spacer material is coated on the surface of the substrate by the coating head, the tip of the coating head is detected by the detection unit. The distance between the tip of the coating head and the surface of the substrate is always detected by detecting the distance between the coating head and the surface of the substrate and moving the coating head relatively to the surface of the substrate based on the detected data. Since the coating head moves at a constant speed and applies the spacer material to the surface of the substrate while maintaining this state, the spacer material as a columnar spacer is controlled as in the conventional case. Sarezu, can also be applied in a uniform thickness in what spacer material, such as, and having never skip around the spacer material as a spin coater, the material utilization efficiency is good.

According to the method of manufacturing a liquid crystal display device according to the second aspect of the present invention, when joining a pair of substrates via the columnar spacer, the columnar spacer is heated at a predetermined temperature, thereby forming a spacer material. Since the elastic modulus is reduced and the pressure is applied in this state, the pressing force can be reduced in accordance with the heating temperature, whereby a pair of substrates can be formed at a desired interval with high accuracy, and the cross-sectional area of the columnar spacer It is not necessary to reduce the dispersion density and the spacer material returns to the original elastic coefficient after pressurization, so that sufficient pressure resistance can be obtained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram conceptually showing one embodiment of a liquid crystal display device manufacturing apparatus according to the present invention.

FIG. 2 is a view showing the application accuracy of a spacer material applied by the manufacturing apparatus of FIG. 1;

FIG. 3 is a diagram showing the relationship between the temperature and the elastic modulus (Young's modulus) of the spacer material shown in FIGS. 1 and 2;

FIG. 4 is a view showing compression characteristics of the columnar spacer when the columnar spacer made of the spacer material applied in FIG. 1 is pressurized in a state of being heated while being interposed between glass substrates.

FIG. 5 is an enlarged sectional view of a main part of the liquid crystal display device.

6A and 6B show a conventional example in which a spacer material is applied to a glass substrate by a spin coater, where FIG. 6A is a plan view and FIG. 6B is a cross-sectional view taken along the line AA.

7A and 7B show compression characteristics of a conventional spacer. FIG. 7A is a diagram showing compression characteristics when a bead spacer is interposed between glass substrates and pressed at room temperature, and FIG. The figure which showed the compression characteristic at the time of pressurizing at normal temperature by interposing between glass substrates.

[Explanation of symbols]

 1, 2 glass substrate 10 columnar spacer 11 liquid crystal 12 spacer material 22 supply unit 23 coating head 24 sensor unit C distance between glass substrates K distance between lower end of coating head and surface of glass substrate

Claims (2)

[Claims] 1. A spacer material is applied to a surface of one of a pair of transparent substrates on which a liquid crystal is sealed, and a surface of the other substrate is patterned by a photolithography method. A liquid crystal display device manufacturing apparatus in which columnar spacers are formed on the surface of the substrate, wherein supply means for supplying the spacer material by a constant amount, and the spacer material supplied by the supply means is fixed on the surface of the one substrate. An apparatus for manufacturing a liquid crystal display device, comprising: a coating head that performs coating while moving at a speed; and a detection unit that detects a distance between a tip portion of the coating head and a surface of the substrate. 2. A method according to claim 1, further comprising: applying a spacer material to a surface of one of the pair of transparent substrates on which the liquid crystal is sealed and facing the other substrate, and patterning the spacer material by photolithography. Forming a columnar spacer on the surface of the substrate, and bonding the pair of substrates through the columnar spacer, wherein the columnar spacer is bonded through the columnar spacer; A method for manufacturing a liquid crystal display device, comprising joining a spacer by heating while heating at a predetermined temperature.