JPH1031222A - Production of liquid crystal panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the cell thickness of a liquid crystal panel uniform by uniformly dispersing spacers into seals with which a substrate for sealing liquid crystal layers is sealed. SOLUTION: A screen plate 1 on which the sealing patterns of longitudinal and transverse sealing lines 2a, 2b are formed, is placed on the substrate and while a spacer-contg. sealant 4 is pressed by a squeegee 3 from above the screen plate 1, this squeegee is moved toward the prescribed printing stage. At this time, the printing direction of the spacer-contg. sealant 4 is set at a direction not intersecting orthogonally with the longitudinal and transverse sealing lines 2a, 2b which are the sealing patterns of the screen plate 1, by which the spacers are uniformly dispersed into the printed seals.

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 panel by screen-printing a sealant for sealing a liquid crystal layer between substrates.

[0002]

2. Description of the Related Art A liquid crystal display device is a display device in which the initial alignment direction of a liquid crystal is changed to another alignment state by an action utilizing the anisotropy of the liquid crystal, and a change in optical characteristics accompanying the change is performed. In recent years, since it is possible to drive at a lower voltage than conventional display devices, it is suitable for LSI driving, it is a low power consumption type, and it is possible to make it thinner and lighter. It is being developed and commercialized to be mounted on OA equipment.

At present, the main axis is a simple matrix type STN type display utilizing the change of alignment state by applying an electric field of liquid crystal, that is, electro-optical characteristics, followed by an active matrix type TFT display. The liquid crystal display is of a sandwich type in which liquid crystal is sandwiched between two glass substrates on which a transparent electrode film is formed, and a polymer thin film for aligning the liquid crystal is formed on the transparent electrode film. In the case of the STN method, the cell thickness between the substrates is 5 to 7 μm.
The orientation of the liquid crystal is controlled by rubbing on the polymer thin film to give a pretilt angle of about 3 to 8 °. This STN system utilizes the birefringence of liquid crystal and the optical rotation of light, and the orientation of the liquid crystal between two substrates is one.
Since it is possible to obtain a remarkably steep threshold value characteristic by twisting from 80 ° to 270 °, the cell thickness is 0.05 to
Requires an accuracy of 0.1 μm.

[0004] The optical characteristics of a liquid crystal panel are obtained by the birefringence, dielectric anisotropy and the like of liquid crystal molecules. In addition, the optical characteristics of the liquid crystal panel are changed by adjusting the composition of the liquid crystal material, including the viscosity and elastic constant, and the component ratio. At present, various liquid crystal materials have been developed, and desired characteristics can be obtained by mixing liquid crystal materials. Ultimately, panel characteristics are determined by a combination of Δn · d, which is a product of the birefringence Δn of the liquid crystal and the thickness d of the liquid crystal layer, and an optical compensation configuration using a retardation film.

Usually, a desired liquid crystal is dropped by a dropping method (Japanese Patent Laid-Open No.
3-179328) or a vacuum injection method. The liquid crystal dropping method is a method in which spacers are dispersed on one glass substrate and liquid crystals prepared in several syringes are dropped on the other glass substrate at a constant pulse. At present, as a sealant used to sandwich liquid crystal between liquid crystal panels, a thermosetting seal is used in a vacuum injection method, and a UV-curable seal is used in a dropping method. In both the vacuum injection method and the dropping method, before the liquid crystal is injected or dropped, seal printing is performed on the substrate in advance. However, printing a sealant mixed with a spacer at a ratio of several wt% by screen printing is preferable. General.

FIG. 3 shows a seal printing method by a screen printing method in a conventional liquid crystal panel manufacturing method, and FIG. 4 is a side view thereof. 3 and 4, reference numeral 1 denotes a screen plate on which a seal pattern including a vertical seal line 2a and a horizontal seal line 2b is formed, 3 denotes a squeegee, 4 denotes a sealant containing a spacer, 5 denotes a stage, and 6 denotes a glass substrate. On which a transparent electrode or the like is formed.

A substrate 6 for printing is placed on a stage 5, and a screen plate 1 on which seal patterns of vertical and horizontal seal lines 2a and 2b are formed is placed thereon. The squeegee 3 is moved in a predetermined printing direction while pressing the agent 4.
As a result, the sealant 4 containing the spacers is
Is printed on the substrate 6 through the seal lines 2a and 2b.

[0008]

When performing seal printing by the screen printing method, it is necessary to uniformly disperse spacers for maintaining the cell thickness in the seal after printing the seal.
This makes it possible to manufacture a liquid crystal panel having a uniform cell thickness. However, actually, the seal pattern shape, printing direction,
Due to the shape anisotropy of the spacer itself, the viscosity of the sealant, the pressing condition of the screen plate and the squeegee used for printing, and the like, the spacer is unevenly dispersed in the seal and the cell thickness becomes nonuniform. In the conventional method shown in FIGS. 3 and 4, the printing direction, that is, the moving direction of the squeegee
Parallel to the seal line 2b formed at
seal lines 2a and 2b in which a sealant 4 containing a spacer is formed on the screen plate 1 by a squeegee 3
When embedding in the sealant, the spacers in the sealant 4 containing spacers are scraped off at the edges of the seal lines 2a and 2b. The sealant embedded in the simple seal line 2b has less spacer. For this reason, there is a problem that uneven distribution of spacers occurs in the vertical and horizontal seal lines printed on the substrate 6, and the cell thickness of the liquid crystal panel after the substrates are bonded becomes non-uniform.

It is an object of the present invention to provide a method of manufacturing a liquid crystal panel capable of uniformly dispersing spacers in a seal printed on a substrate for sealing a liquid crystal layer, thereby making the cell thickness uniform. It is.

[0010]

According to a first aspect of the present invention, there is provided a method of manufacturing a liquid crystal panel, wherein a sealant containing a spacer for sealing the periphery of a liquid crystal layer sandwiched between a pair of substrates is provided by a vertical and horizontal seal line. A method for manufacturing a liquid crystal panel in which printing is performed in a predetermined direction on one of the substrates via a screen plate having a seal pattern made of It is characterized in that the direction is not orthogonal to the horizontal seal line.

According to the method of manufacturing a liquid crystal panel of the present invention, the printing direction of the sealant containing spacers is set to a direction that is not orthogonal to the vertical and horizontal seal lines of the screen plate. The effect of scraping at the edges of the vertical and horizontal seal lines is almost equal, and the spacers can be evenly distributed on the vertical and horizontal seal lines on the printed substrate, so that the cell thickness after bonding the substrate, In particular, the cell thickness at the time of sealing can be made uniform.

According to a second aspect of the present invention, there is provided a method of manufacturing a liquid crystal panel.
2. The method for manufacturing a liquid crystal panel according to claim 1, wherein the printing direction of the sealing agent containing the spacer is set to 40 [deg.] To 50 [deg.] With the vertical and horizontal sealing lines which are the sealing pattern of the screen plate.
The direction has an angle of ゜. As described above, the printing direction of the sealant containing the spacer is set to the vertical and horizontal seal lines, which are the seal patterns of the screen plate, by 40 ° to 50 °.
The direction having an angle of ゜ makes the effect of the spacers in the sealant being scraped off at the edges of the vertical and horizontal seal lines of the screen plate more equal, and the vertical and horizontal seal lines on the printed board are more similar. Since the spacers can be dispersed more uniformly, the cell thickness after bonding the substrates, particularly the cell thickness at the time of sealing, can be made more uniform.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a conceptual diagram showing a seal printing method by a screen printing method in a liquid crystal panel manufacturing method according to an embodiment of the present invention, and the same parts as those in FIG. 3 are denoted by the same reference numerals. The side view is the same as FIG. 4 used in the conventional example.

In the method of manufacturing a liquid crystal panel according to this embodiment, a screen plate 1 on which a seal pattern of vertical and horizontal seal lines 2a and 2b is formed is mounted on a substrate 6, and a squeegee 3 is used to seal the spacer with a squeegee 3 on the screen plate 1. While pressing the squeegee 4, the squeegee 3 is moved in a predetermined printing direction. The printing direction of the spacer-containing sealant 4 is characterized by being a direction that is not orthogonal to the vertical and horizontal seal lines 2a and 2b, which are the seal patterns of the screen plate 1, and the rest is the same as the conventional example.

FIG. 2 shows a seal pattern of the screen plate 1.
When the printing direction is changed with respect to
Result of measuring the number of spacers included in the seal line
Is shown. The horizontal axis in FIG. 2 is the vertical seal line of the screen plate 1.
Angle between the squeegee 2a and the printing direction (moving direction of the squeegee 3)
Degrees. The vertical axis in FIG. 2 indicates the liquid crystal panel in each printing direction by one.
0 panels were manufactured, and 10 places (sealers)
Parts corresponding to the ins 2a and 2b (5 places each)
Average value of pacer quantity, 2mm^Two(1mm ^Two× 2m
m^TwoShows the number of spacers per square bracket. In addition, in FIG.
The substrate 6 is marked through the seal line 2a of the screen plate 1.
The measurement results for the printed seal line.
Printing on the substrate 6 through the seal line 2b of the clean plate 1
It is a measurement result in the seal line performed.

The liquid crystal panel manufactured in FIG. 2 was prepared by using a UV curable resin as a sealant and a glass fiber of 7 μm as a spacer as a sealant 4 containing a spacer, and mixing them at a ratio of 2 wt% to the sealant. Seal lines 2a of the screen plate 1 corresponding to the seal pattern of the liquid crystal panel,
The width of 2b was 0.25 mm. The clearance between the screen plate 1 and the substrate 6 for seal printing was 0.5 mm, and the feed speed of the squeegee 3 was 1 mm / sec.

As shown in FIG. 2, when the printing direction, which is the moving direction of the squeegee 3, forms an angle of 0 ° and 90 ° with the seal line 2a, ie, the printing direction is the seal line 2a.
a, 2b, the substrate 6
The deviation of the distribution of the spacers is large in the vertical and horizontal seal lines printed on the seal line, whereas the print direction is the seal line 2a,
When not orthogonal to 2b, the dispersion bias of the spacer is reduced. In particular, it was confirmed that the effect was great by setting the angle between 40 ° and 50 °. This is because, for example, when the printing direction and the seal line 2a are set at 45 °, the action of the sealing agent 4 containing spacers being scraped off at the time of printing by the pattern edges of the seal lines 2a and 2b of the screen plate 1 becomes uniform. It is.

As described above, by making the printing direction of the spacer-containing sealant 4 not orthogonal to the seal lines 2a and 2b which are the seal patterns of the screen plate 1, the dispersion of the spacers in the printed seal can be made uniform. The cell thickness after bonding the substrates, particularly the cell thickness at the time of sealing, can be made uniform. In particular, a greater effect can be obtained by setting the angle between the printing direction and the seal lines 2a and 2b in the range of 40 ° to 50 °.

[0019]

According to the method of manufacturing a liquid crystal panel of the present invention, a sealant containing a spacer for sealing the periphery of a liquid crystal layer sandwiched between a pair of substrates is formed by forming a seal pattern comprising vertical and horizontal seal lines. A method of manufacturing a liquid crystal panel that prints in a predetermined direction on one substrate via a screen plate, wherein the printing direction of the sealing agent containing spacers is perpendicular to the vertical and horizontal seal lines that are the seal pattern of the screen plate. When the direction is not set, the effect that the spacer in the sealant is scraped off at the edges of the vertical and horizontal seal lines of the screen plate is almost equal, and the spacers are evenly distributed on the vertical and horizontal seal lines on the printed board. Therefore, the cell thickness after bonding the substrates, particularly the cell thickness at the time of sealing, can be made uniform.

The printing direction of the sealant containing the spacer is set to a direction having an angle of 40 ° to 50 ° with the vertical and horizontal seal lines, which are the seal patterns of the screen plate, so that the spacer in the sealant is screened. The effect of scraping off at the edges of the vertical and horizontal seal lines of the plate is more equal, the spacers can be more evenly distributed and the cell thickness can be more uniform.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram illustrating a method for manufacturing a liquid crystal panel according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a result of measuring the number of spacers included in a seal line of a manufactured liquid crystal panel when a printing direction is changed with respect to a seal pattern of a screen plate in the embodiment of the present invention.

FIG. 3 is a conceptual diagram showing a conventional method for manufacturing a liquid crystal panel.

FIG. 4 is a side view of FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Screen plate 2a Vertical seal line 2b Horizontal seal line 3 Squeegee 4 Sealant with spacer 5 Stage 6 Substrate

Claims (2)

[Claims] 1. A sealant containing a spacer for sealing the periphery of a liquid crystal layer sandwiched between a pair of substrates is provided on one of the substrates via a screen plate on which a seal pattern including vertical and horizontal seal lines is formed. A method of manufacturing a liquid crystal panel that prints in a predetermined direction, wherein the printing direction of the sealant containing the spacer is a direction that is not orthogonal to the vertical and horizontal seal lines that are the seal pattern of the screen plate. Liquid crystal panel manufacturing method. 2. The method for manufacturing a liquid crystal panel according to claim 1, wherein the printing direction of the sealant containing the spacer is a direction having an angle of 40 ° to 50 ° with the vertical and horizontal seal lines as the seal pattern of the screen plate. .