JP2001343649A - Printing apparatus for alignment layer formation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printing apparatus improving uniformity of printed film thickness of an alignment layer for a liquid crystal display device. SOLUTION: The printing apparatus is provided with a first roll having a recess to hold an alignment material on the surface, a second roll to remove an excessive alignment material on the surface, and a third roll having on its surface a printing plate 4a to transfer the alignment material from the surface of the first roll. The printing plate 4a comprises a base film 10 and a printing surface part 9 made of an elastic resin and used for transferring the alignment material. A groove (a recess 11 on the rear side of the base film) with a specified width is formed on the rear surface of the base film 10 on an edge part position of the printing surface part 9. Increase of pressure applied to the edge of the printing surface part 9 on the printing plate 4a is suppressed by the groove and the alignment layer with uniform film thickness is formed on a substrate for the liquid crystal display device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing apparatus for forming an alignment film on an electrode forming surface of a liquid crystal element substrate by flexographic printing, and more particularly to a structure of a printing roll for transferring an alignment material by pressing against an anilox roll. The present invention relates to a structure of a printing plate used by being attached to the surface of the printing roll.

[0002]

2. Description of the Related Art A liquid crystal element has a structure in which liquid crystal is sandwiched between a pair of transparent substrates made of glass or the like, and transparent display electrodes are formed on mutually facing surfaces of the pair of substrates. In addition, an alignment film for aligning liquid crystal molecules in a predetermined alignment state is provided thereon.

The alignment film is formed by printing an alignment material made of polyimide or the like on the electrode forming surface of the substrate, and the printing of the alignment material is generally performed by coating a liquid alignment material on the alignment material supply surface with a constant thickness. And a transfer printing apparatus that transfers the alignment material onto a substrate using a printing plate.

[0004] Regarding the technology of the transfer printing device,
102694, JP-A-6-238876,
It is disclosed in JP-A-8-295006 and the like. FIG. 5 is a sectional view showing an example of these transfer printing apparatuses.

A method for printing an alignment film using this transfer printing apparatus will be described. In the figure, reference numeral 1 denotes an anilox roll, which is formed by coating a ceramic or the like on the surface of a metal roll and forming a large number of recesses of several μm to several tens μ by laser processing. An alignment material 6 such as a polyimide varnish is dropped and filled from the alignment material supply device 5 into the concave portion. The surface of the doctor roll 3 formed by winding ethylene propylene rubber around the surface of the metal roll is pressed against the surface of the anilox roll 1 to remove excess alignment material 6 on the surface of the anilox roll 1. The surface of the printing plate 4 of the printing roll 2 (made of metal) rotating in the opposite direction (synchronously) to the anilox roll 1 is pressed against the surface of the anilox roll 1 from which the excess alignment material 6 has been removed, and the surface of the anilox roll 1 is pressed. The alignment material 6 is transferred to the surface of the printing plate 4. Next, the surface of the printing plate 4 is pressed against the surface of the printing medium 8 such as a liquid crystal element substrate arranged on the stage 7 to transfer and print the alignment material 6 on the surface of the printing medium 8.

The printing plate 4 has a structure in which a resin portion such as butyl rubber, ethylene propylene rubber or photosensitive rubber / photosensitive resin (APR resin) is adhered to a base film such as polyester. Columnar projections (for example, 10-30 μm wide, 20-40 μm deep)
m) is formed. The liquid of the alignment material 6 stays between these projections. The printing plate 4 is wound substantially half way around the peripheral surface of the printing roller 2 and is attached to the peripheral surface of the roller with a double-sided adhesive tape or the like.

[0007]

When printing an alignment film using the printing plate 4, there are the following problems. (1) Printing plate 4 of printing roll 2 on anilox roll 1
When pressing, the transfer pressure increases at the surface edge of the printing plate, and the alignment material 6 is applied to the edge of the surface of the printing plate 4.
Is often transferred. (2) As a result of the transfer of a large amount of the alignment material to the surface edge of the printing plate 4, a larger number of alignment films are transferred and printed on the print marks at the edge of the printing plate 4 of the printing medium than in other places. The thickness of the film becomes non-uniform, and the rubbing of the alignment process becomes non-uniform around the alignment film, which causes the alignment defect of the liquid crystal.

A technique for improving the above conventional technique is disclosed in Japanese Patent Application Laid-Open
-150241 and JP-A-11-59004.

In Japanese Patent Application Laid-Open No. 5-150241, the periphery of the printing surface of the printing plate is formed into a tapered shape to reduce the transfer pressure at the periphery of the printing surface. Also, Japanese Patent Application Laid-Open
In Japanese Patent Application Laid-Open No. 1-59004, a contrivance is made so that the frequency of unevenness in the edge region of the printing surface is made larger than that in the inner region of the printing surface so that the transfer amount of the alignment material in the edge region of the printing surface does not increase.

In these techniques, although a certain effect has been obtained in improving the uniformity of the thickness of the alignment film as compared with the above-mentioned conventional technique, it cannot be said that it is still sufficient.

Accordingly, an object of the present invention is to provide a printing apparatus for forming an alignment film, which solves the above-mentioned problems of the prior art, and in particular, a printing apparatus for forming an alignment film having a printing roll and a printing plate having improved structures. It is in.

[0012]

According to a first aspect of the present invention, there is provided a printing apparatus for forming an alignment film, comprising: a first roll having a concave portion for holding an alignment material on its surface; A second roll for removing excess of the alignment material in the concave portion;
A third roll having on its surface a printing plate for transferring the alignment material from the surface of the first roll by pressing against the first roll, wherein the printing plate has a surface for transferring the alignment material. And a groove having a predetermined width at a position located at an edge portion of the printing surface portion and the back surface of the printing surface portion.

A second configuration of the printing apparatus for forming an alignment film according to the present invention includes a first roll having a concave portion for holding an alignment material on a surface thereof, and an excessive amount of the concave portion which is pressed against the first roll. A second roll for removing the alignment material, and a third roll having a printing plate on a surface thereof for transferring the alignment material from the surface of the first roll by pressing against the first roll, The third roll has a groove of a predetermined width on the surface of the third roll below the printing plate located at the edge of the printing surface portion.

In the second configuration of the present invention, the inside of the groove of the third roll can be filled with a flexible resin such as a silicone resin or a polyurethane resin.

In the first and second configurations of the present invention, a metal roll or a roll in which a metal roll is coated with a resin can be used as the third roll,
The groove of the third roll in the second configuration is formed by laser processing.

In the present invention, as in the first and second configurations, a groove having a predetermined width is provided at a position located at the edge of the printing surface on the back surface of the printing plate or at the surface of the third printing roll. The feature is that these grooves make it possible to suppress an increase in the printing pressure at the edge of the printing surface of the printing plate. As a result, an alignment film having a uniform thickness can be formed on the surface of the liquid crystal element substrate.

[0017]

Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic view showing the structure of a printing plate of a printing apparatus for forming an alignment film according to a first embodiment of the present invention. FIG. 1 (a) is a plan view, and FIG. AA 'of 1 (a)
FIG.

As shown in FIG. 1, a printing plate 4a of a printing apparatus for forming an alignment film according to an embodiment of the present invention has a printing surface portion 9 made of an elastic resin formed on a base film 10, and an edge portion of the printing surface portion 9 A feature of the structure is that a groove (indicated by a concave portion 11 on the back surface of the base film) is formed on the back surface of the base film 10 located.

As the base film 10, a polyester resin or a polyimide resin is used, and as the elastic resin of the printing surface portion 9, a resin such as butyl rubber, ethylene propylene rubber or photosensitive rubber / photosensitive resin (APR resin) can be used. Projections having a depth of 10 to 20 μm and a width of 10 to 30 μm are formed on the surface of the printing surface section 9 by photolithography.

As shown in FIG. 1B, the base film rear concave portion 11 has a rectangular shape or a V-shaped groove (shown by a base film rear concave portion 11a) as shown in FIG. A groove having a shape such as a shape can be formed.

FIG. 3 is a schematic sectional view of a printing apparatus using the printing plate of FIG. 1, and has a configuration in which the printing plate 4 is changed to a printing plate 4a in the conventional transfer printing apparatus of FIG. . The method of printing the alignment material 6 on the printing material 8 (liquid crystal element substrate) is the same as the method of the related art described with reference to FIG.

In the present invention, the surface of the printing plate 4a of the printing roll 2 (third roll) is fixed to the anilox roll 1 (first roll).
When the alignment material 6 is transferred to the printing surface 9 of the printing plate 4a by pressing against the surface of the printing plate 4a, the base film of the groove continuous with the back surface of the base film located at the edge of the printing surface 9 of the printing plate 4a. Since the back recess 11 is provided, there is an effect that an increase in the pressing force of the edge of the printing surface 9 with the surface of the anilox roll 1 can be suppressed. As a result, excessive transfer of the alignment material 6 to the edge of the printing surface 9 can be prevented. Also, when printing the alignment material 6 transferred to the printing surface portion 9 of the printing plate 4a on the printing medium 8 (substrate for a liquid crystal element), the increase in the printing pressure at the edge portion of the printing surface portion 9 of the printing plate 4a is reduced. Since it can be suppressed, the printed film thickness of the alignment material 6 on the surface of the printing object 8 (substrate for liquid crystal element) can be made uniform.

The base film back recess 11 on the back of the base film 10 of the printing plate 4a is formed by laser processing. The processing depth of the concave portion 11 on the rear surface of the base film is determined in consideration of the thickness of the material of the printing surface portion 9 and the magnitude of the printing pressure.

In the above-described embodiment, the printing plate 4a is formed by attaching an elastic resin to the base film 10. However, the entire printing plate may be composed of only the above-mentioned elastic resin. In this case, the groove on the back surface of the printing plate 4a can be formed by photolithography. Note that reference numeral 3 in FIG. 3 denotes a doctor roll (second roll).

Next, a printing apparatus for forming an alignment film according to a second embodiment of the present invention will be described with reference to the drawings.

FIG. 4 is a schematic sectional view of a printing apparatus for forming an alignment film according to a second embodiment of the present invention. The printing apparatus for forming an alignment film according to the present embodiment is a conventional transfer printing apparatus shown in FIG. 5 in which the structure of a printing roll is particularly improved to suppress an increase in printing pressure at the printing surface edge of a printing plate. .

The printing apparatus for forming an alignment film according to the present embodiment
The feature of the present invention is that a groove 12 is provided on the surface of the printing roll 2a corresponding to the edge of the printing surface of the printing plate 4b. In FIG. 4, the filler 13 is filled in the groove 12, but the filler 13 may not be filled and remain in a cavity. As the filler 13 to be filled in the groove 12, flexible silicone rubber or polyurethane rubber is used.

In the present embodiment, the groove provided on the surface of the printing roll 2a can reduce (absorb) the increase in the printing pressure at the edge of the printing surface of the printing plate 4b. This has the effect of suppressing an increase in the film thickness of the printed material edge portion of the oriented material 6.

The printing plate 4b of the present embodiment comprises a base film such as a polyester or polyimide resin and a printing surface portion of a resin such as butyl rubber, ethylene propylene rubber or photosensitive rubber / photosensitive resin (APR resin). . In the present embodiment, it is not necessary to provide a groove at a position located at the edge of the printing surface on the back surface of the base film. As the printing roll 2a, a metal roll of stainless steel or aluminum, or a roll obtained by coating a fluororesin or a vinyl chloride resin on these metal rolls can be used. Laser processing is used to form the grooves 12 on the surface of the printing roll 2a.

[0031]

As described above, in the printing apparatus for forming an alignment film according to the present invention, a predetermined width of the back surface of the base film or the surface of the printing roll corresponding to the position of the edge of the printing surface of the printing plate. By providing the groove, an increase in the printing pressure at the edge of the printing surface of the printing plate can be suppressed, and an effect that an alignment film having a uniform film thickness can be accurately formed on the surface of the liquid crystal element substrate is obtained.

[Brief description of the drawings]

FIG. 1 is a plan view and a cross-sectional view of a printing plate of a printing apparatus for forming an alignment film according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating another example of a printing plate of the printing apparatus for forming an alignment film according to the first embodiment of the present invention.

FIG. 3 is a schematic sectional view of a printing apparatus for forming an alignment film using the printing plate of FIG. 1;

FIG. 4 is a schematic cross-sectional view of a printing apparatus for forming an alignment film according to a second embodiment of the present invention.

FIG. 5 is a schematic sectional view of a conventional transfer printing apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Anilox roll 2, 2a Printing roll 3 Doctor roll 4, 4a, 4b Printing plate 5 Alignment material supply device 6 Alignment material 7 Stage 8 Printed material 9 Printing surface part 10 Base film 11, 11a Concave part of base film back surface 12 Groove 13 Filler

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) G02F 1/13 101 B41F 13/10 Z F Term (Reference) 2C034 AA02 2H088 FA30 HA03 MA20 2H090 HB07Y HB08Y HC06 2H113 AA05 BA01 BB09 BB22 BC00 CA17 2H114 AA01 AA14 BA01 DA46 DA52 DA56 EA02 EA04

Claims (11)

[Claims] A first roll having a concave portion for holding an alignment material on a surface thereof; a second roll for pressing against the first roll to remove an excessive amount of the alignment material in the concave portion;
A third roll having, on its surface, a printing plate for transferring the alignment material from the surface of the first roll by pressing against the roll of (a), wherein the printing plate has a printing surface portion for transferring the alignment material on the surface. And a groove having a predetermined width at a position located at an edge of the printing surface on the back surface. 2. A first roll having a concave portion on its surface for holding an alignment material, a second roll for pressing against the first roll to remove excess alignment material in the concave portion, and
And a third roll having a printing plate on its surface for transferring the alignment material from the first roll surface by pressing against the first roll, and the third roll is located at an edge of the printing surface portion. A printing device for forming an alignment film, comprising a groove having a predetermined width on a surface of the third roll under the printing plate. 3. The printing apparatus for forming an alignment film according to claim 2, wherein a flexible resin is filled in the groove of the third roll. 4. The printing apparatus for forming an alignment film according to claim 3, wherein a silicone resin or a polyurethane resin is used as said flexible resin. 5. The printing device for forming an alignment film according to claim 1, wherein the printing plate is made of an elastic resin. 6. The printing plate according to claim 1, wherein the printing plate comprises a base film and an elastic resin.
The printing apparatus for forming an alignment film according to the above. 7. The printing apparatus for forming an alignment film according to claim 6, wherein a polyester resin or a polyimide resin is used as the base film. 8. The printing apparatus for forming an alignment film according to claim 5, wherein butyl rubber, ethylene propylene rubber, or photosensitive rubber or photosensitive resin is used as the elastic resin. 9. The printing apparatus for forming an alignment film according to claim 1, wherein the third roll is formed of a metal roll or a roll obtained by coating a metal roll with a resin. 10. The printing apparatus for forming an alignment film according to claim 1, wherein the grooves on the back surface of the printing plate are formed by laser processing or photolithography. 11. The groove of the surface of the third roll is formed by laser processing.
5. The printing device for forming an alignment film according to 3 or 4.