JP3086622B2 - Thin film printing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film printing apparatus capable of printing a film having a uniform thickness, and more particularly, to printing a thin film such as an alignment film of a liquid crystal display, an insulating film, and an overcoat film of a color filter. The present invention relates to a thin film printing apparatus formed by printing on a body.

[0002]

2. Description of the Related Art Conventionally, an alignment film, an insulating film,
A thin film printing apparatus used for forming a thin film such as an overcoat film of a color filter is disclosed in, for example, Japanese Patent Application Laid-Open No. 6-238876.
No. 6,009,036.

FIG. 3 is a schematic sectional view of the thin film printing apparatus. In FIG. 3, an anilox roll (printing liquid transfer means) 1 having a large number of concave cells on the surface and a printing liquid 2 supplied onto the anilox roll 1 are provided. The printing liquid supply device (printing liquid supply means) 3 is pressed against the roll surface of the anilox roll 1 and slidably rotated (rotation with different tangential velocities at the pressed position) to transfer the printing liquid 2 into the concave cell. Roll (printing liquid amount adjusting means) 4 for filling and measuring, an elastic relief plate 7 for printing the printing liquid 2 transferred from the anilox roll 1 on a printing medium 6 arranged on a printing stage 5, and the elastic relief plate 7 The thin film printing apparatus is constituted by a printing roll 8 or the like on which the printing device is mounted.

A contact portion between the anilox roll 1 and the doctor roll 4 has a printing liquid pool 9 as shown in FIG.
Is formed.

The anilox roll 1 is manufactured by forming a concave cell by mechanical engraving on the surface of a metal roll, plating hard chrome on the surface, and polishing the surface.

The doctor roll 4 has a surface formed of an elastic body made of rubber or the like.

The printing liquid 2 is supplied by being dropped onto the anilox roll 1 from a printing liquid supply device 3 by a dispenser 10.

[0008]

In recent years, liquid crystal display devices have been improved in definition and contrast, and the thickness unevenness of the alignment film at a level which has not been a problem as display unevenness in the past has been reduced to display unevenness. Since it has come to appear, further uniformity of the thickness of the alignment film is required.

However, according to the conventional thin-film printing apparatus, the printing liquid 2 is dropped and supplied from the printing liquid supply device 3 onto the anilox roll 1 by the dispenser 10. When contacted by dropping on the fine printing liquid 1 as shown in FIG.
1 may splatter. When the scattered minute printing liquid 11 enters the printing liquid pool 9, fine bubbles 12 may be generated in the printing liquid pool 9 as shown in FIG.

When the air bubbles 12 are caught between the anilox roll 1 and the doctor roll 4,
The necessary amount of the printing liquid 2 cannot be filled in the concave cells on the surface of the anilox roll 1 where the bubbles 12 existed, and the printing liquid 2 is filled in the elastic relief plate 7 attached to the printing roll 8. When transferred and printed on the glass substrate (substrate to be printed) 6, the part 14 of the thin film 13 after printing may be thinner as shown in FIG.

If the above-described phenomenon occurs during the printing of the alignment film of the liquid crystal display device, the thin portion 14 of the thin film, that is, the thin portion of the alignment film, can be used to improve the definition of the recent liquid crystal display device. In addition, as a result of progress in high contrast and the like, display unevenness appears, which is one of the causes of lowering the non-defective product rate.
One.

As a means for improving the printability of a thin film printing apparatus, an anilox roll is used to reliably fill a concave cell on the anilox roll surface with a printing liquid as disclosed in Japanese Patent Application Laid-Open No. Hei 5-31882. The rubber roll is slid or rotated synchronously (rotation with the same tangential velocity at the pressed position) so that the printing liquid is filled so that the printing liquid is filled, and the amount of the printing liquid in the concave cell is adjusted by the doctor roll. A thin film printing apparatus has been proposed.

However, in this thin film printing apparatus, there is a problem in that the number of rolls is increased and the structure becomes complicated as compared with the above-mentioned thin film printing apparatus, so that the manufacturing cost of the apparatus itself is increased.

As another means for improving the printability of the thin-film printing apparatus, there is provided a method for improving the accuracy of the concave cell capacity on the anilox roll surface as disclosed in JP-A-6-238876. Then, a thin film printing apparatus provided with an anilox roll whose surface is polished by engraving a concave cell with a laser beam after polishing and polishing the surface of the anilox roll with a ceramic has been proposed.

However, in this thin film printing apparatus, when the printing liquid is dropped on the anilox roll and comes into contact with the anilox roll, the printing liquid scatters and enters the printing liquid pool, and when a phenomenon that bubbles are generated occurs, There is a problem that unevenness in the thickness of the thin film cannot be eliminated.

The thin-film printing apparatus of the present invention solves the above-mentioned problems, and does not increase the manufacturing cost of the apparatus itself. It is an object of the present invention to provide a thin-film printing apparatus capable of greatly reducing the variation in the thickness.

[0017]

According to the first aspect of the present invention, there is provided a printing liquid transferring means for transferring a printing liquid to a relief plate for printing at least a predetermined pattern on a printing medium. A thin film printing apparatus comprising: a printing liquid amount adjusting unit that measures a predetermined amount of the printing liquid on the printing liquid transfer unit; and a printing liquid supply unit that supplies the printing liquid. It is supplied on the printing liquid amount adjusting means.

According to a second aspect of the present invention, in the first aspect of the invention, the printing liquid amount adjusting means has at least a surface formed of an elastic body.

[0019]

According to the present invention, the printing liquid is not supplied to the printing liquid transferring means having a high surface hardness as in the prior art, but is supplied to the printing liquid amount adjusting means having at least its surface formed of an elastic material. By doing so, when the printing liquid is supplied onto the printing liquid amount adjusting means and brought into contact with the printing liquid, the minute printing liquid does not scatter. Therefore, the scattered fine print liquid does not enter the print liquid pool and generate fine bubbles, and the fine bubbles may be caught between the print liquid transfer means and the print liquid amount adjusting means. Absent. For this reason, the required amount of the printing liquid can be evenly filled in the concave portions on the surface of the printing liquid transfer means, and a thin film having significantly reduced thickness unevenness can be obtained.

[0020]

【Example】

[First Embodiment] A first embodiment of a thin film printing apparatus according to the present invention will be described with reference to FIG. The same parts as those in the conventional example are denoted by the same reference numerals, and description thereof will be omitted. In FIG. 1, the uppermost part of the doctor roll 4 formed on the surface of ethylene propylene rubber is disposed higher than the uppermost part of the anilox roll 1 having a large number of concave cells whose surfaces are plated with hard chrome. , Set the doctor roll 4 to rotate at a tangential speed of 100 mm / sec,
The anilox roll 1 was set to rotate at a tangential speed of 300 mm / sec.

A polyimide (printing liquid) 2 serving as an alignment film of a liquid crystal display device is supplied onto the doctor roll 4 by being dropped from a printing liquid supply device 3 by a dispenser 10.
The doctor roll 4 and the anilox roll 1 were brought into pressure contact with each other at a contact pressure (equivalent to a rubber pushing amount) of 0.35 mm, and were slid and rotated so that the direction of the tangential velocity at the pressed position was the same.

Then, the printing roll 8 on which the APR plate (elastic letterpress) 7 is mounted and the anilox roll 1 are pressed and rotated synchronously, and the polyimide 2 is moved from the anilox roll 1 to the A roll.
After transferring to the PR plate 7, printing was performed on a glass substrate (substrate to be printed) 6 having a transparent electrode pattern and serving as an electrode substrate of a liquid crystal display device arranged on the printing stage 5. When the thickness of this polyimide thin film was measured, the average in-plane was about 60 nm and the in-plane variation was 2 nm or less. When printing was performed a plurality of times, the variation for each printing was 3 nm or less. The in-plane variation and the variation for each printing were good, and even when operated as a high-definition, high-contrast liquid crystal display device, the display defect was less than 1% due to the variation in the thickness of the alignment film.

[Second Embodiment] A second embodiment of the thin film printing apparatus according to the present invention will be described with reference to FIG. The same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. In FIG. 2, the configuration of the second embodiment is the same as the configuration of the first embodiment except that the uppermost part of the doctor roll 4 and the uppermost part of the anilox roll 1 are arranged at the same height.

A polyimide thin film as an alignment film of a liquid crystal display device was printed and the film thickness was measured in the same manner as in the first embodiment, and the film thickness was measured to be about 60 nm with an in-plane variation of 2.2 n.
m or less. When printing was performed a plurality of times, the dispersion for each printing was 3.5 nm or less. The in-plane variation and the variation for each printing were good, and even when operated as a high-definition, high-contrast liquid crystal display device, display defects due to variations in the thickness of the alignment film were about 1%.

COMPARATIVE EXAMPLE The same procedure as in the first embodiment was performed except that polyimide 2 was supplied dropwise onto the anilox roll 1 from the printing liquid supply device 3 by the dispenser 10 and supplied. When the thickness of this polyimide thin film was measured, the average in-plane was about 60 nm, and the in-plane variation was 4 nm or less. When printing was performed a plurality of times, the variation for each printing was 6 nm or less. Both the in-plane variation and the variation for each printing were not good, and when operated as a high-definition, high-contrast liquid crystal display device, display defects due to variations in the thickness of the alignment film were about 30%.

Although the doctor roll 4 is used in the above embodiment, a doctor blade may be used instead of the doctor roll 4. In addition, doctor roll 4
It may swing (reciprocate in the direction along the rotation axis) during rotation, and the present invention is not limited to the above embodiment.

[0027]

Since the thin film printing apparatus of the present invention has the above-described structure, the printing liquid is not supplied to the printing liquid transferring means having a high surface hardness, but at least the surface of the printing liquid is formed by an elastic material. By supplying the printing liquid on the liquid amount adjusting means, when the printing liquid is supplied to and contacted with the printing liquid amount adjusting means, minute printing liquid does not scatter.

Therefore, since the scattered minute printing liquid does not enter the printing liquid pool and generate minute bubbles,
Since fine bubbles are not caught between the printing liquid transferring means and the printing liquid amount adjusting means, the printing liquid can be evenly filled in the recesses on the surface of the printing liquid transferring means, and the manufacturing cost of the apparatus itself is reduced. Without increasing the film thickness, it is possible to obtain a thin film in which the film thickness unevenness is greatly reduced with the same number of parts as in the conventional apparatus.

Further, when the thin film is an alignment film of a liquid crystal display device, display unevenness of the liquid crystal display device due to unevenness of the thickness of the alignment film can be greatly reduced.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a first embodiment of a thin film printing apparatus according to the present invention.

FIG. 2 is a schematic sectional view showing a second embodiment of the thin film printing apparatus of the present invention.

FIG. 3 is a schematic sectional view of a conventional thin film printing apparatus.

FIG. 4 is a schematic cross-sectional view illustrating a state in which a printing liquid is dropped on a printing liquid transfer unit and is brought into contact with the printing liquid transfer unit.

FIG. 5 is an explanatory view showing a state where a thin film is printed on a printing medium by a conventional thin film printing apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Printing liquid transfer means (anilox roll) 2 Printing liquid (polyimide) 3 Printing liquid supply means (printing liquid supply device) 4 Printing liquid amount adjustment means (doctor roll) 5 Printing stage 6 Printed object (glass substrate) 7 Elastic letterpress (APR version) 8 Printing roll 9 Printing liquid pool 10 Dispenser 11 Fine printing liquid 12 Bubbles 13 Thin film after printing 14 Thin part

Continued on the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) B41F 17/14 G02F 1/1337 B41F 31/08 B41F 31/14

Claims (2)

(57) [Claims] 1. A printing liquid transferring means for transferring a printing liquid to a relief plate for printing at least a predetermined pattern on a printing medium, and the amount of the printing liquid on the printing liquid transferring means is adjusted to a predetermined amount.
A thin film printing apparatus comprising a printing liquid amount adjusting means for measuring and a printing liquid supply means for supplying the printing liquid, wherein the printing liquid is supplied onto the printing liquid amount adjusting means. Printing device. 2. The thin-film printing apparatus according to claim 1, wherein the printing liquid amount adjusting means has at least a surface formed of an elastic body.