KR101351616B1 - Apparatus for Optical Sheet and Method for Preparing the Optical Sheet Using the Apparatus - Google Patents

Abstract

The optical sheet manufacturing apparatus of the present invention comprises a soft mold having a pattern formed thereon; A master roll in contact with the soft mold and laminating the soft mold and the base film into which the coating liquid is injected; A first roll engaged with the master roll to press the soft mold and the base film into which the coating liquid is injected; A second roll separating the laminated film from the first roll into an optical film having a soft mold and a pattern formed thereon; And a pre-coating unit for precoating the soft mold transferred from the second roll, wherein the pre-coating unit transfers the transferred soft mold to the main coating unit. And a coating roll for precoating the soft mold by rotation by receiving the coating liquid by a resin supply tank, wherein the guide roll and the coating roll are arranged in a zigzag without interlocking with each other. The optical sheet manufacturing apparatus of the present invention can widen the contact surface between the mold and the coating roll, thereby improving productivity in manufacturing the optical sheet, and smooth filling and removing bubbles.

Description

Apparatus for Optical Sheet and Method for Preparing the Optical Sheet Using the Apparatus}

The present invention relates to an optical sheet manufacturing apparatus and an optical sheet manufacturing method using the same. More specifically, in the apparatus for manufacturing a soft mold roll-to-roll optical sheet, the present invention improves productivity compared to the conventional method by providing a coating device in which the contact surface of the soft mold and the coating roll is widened during precoating, and smooth solution filling and bubble removal are possible. It relates to a possible optical sheet manufacturing apparatus and an optical sheet manufacturing method using the same.

In the back light unit of the LCD, an optical sheet is used to promote the refraction and diffusion of the light to increase the uniformity and brightness of the light. Such an optical sheet includes a diffusion sheet for diffusing light, a prism sheet for condensing and diffusing light diffused on the upper surface of the diffusion sheet, and a protective sheet for protecting the diffusion sheet and the prism sheet. .

Such an optical sheet is generally subjected to a certain patterning treatment on the surface in order to increase the light diffusing ability and brightness in addition to the properties originally possessed. In recent years, a large amount is processed by a roll to roll method.

The roll-to-roll method includes a hard mold type using a metal mold processed with a pattern and a soft mold type using a film mold.

The hard mold type is difficult to implement a hemispherical microlens pattern, while the soft mold type has a merit of implementing various types of patterns including a microlens pattern.

However, when the moving speed of the mold is increased to increase the productivity of the optical sheet, bubbles are formed in the pattern or coating liquid is not completely injected, resulting in a fatal damage to the quality of the product. In particular, in the case of the hemispherical microlens pattern of the pattern shape, bubbles are more serious. Accordingly, in most soft mold methods, a separate crude liquid filling device is provided before the main coating to perform precoating.

Korean Patent No. 887340 discloses a method of partially filling a coating liquid by introducing one or more squeegee rolls which are compressed by filling a polymer resin into a pattern of a film. Figure 1 schematically shows an optical sheet manufacturing apparatus of the squeegee roll method. As shown in FIG. 1, in the conventional optical sheet manufacturing apparatus, a soft mold 20 having a pattern formed thereon is brought into contact with a part of the master roll 100. The soft mold 20 is filled along the outer circumference of the master roll 100 to fill the coating liquid inside the pattern, usually after the first coating with a pre-coating to the main coating. After the main coating is completed by the coating liquid injection device 110, the soft mold 20 is laminated with the base film 10, and is pressed by the first roll 120 formed by being engaged with the master roll 100 and thus laminated. The laminated film 11 is cured while being transported along the master roll 100. The cured film is separated into a soft mold 20 and an optical film 12 having a pattern. The soft mold 20 is separated by a second roll 130 and transferred to the pre-coating portion A. The pre-coating portion (A) is engaged with the guide rolls (140, 141, 142) for transferring the transferred soft mold 20 to the main coating portion and the coating roll 150 for pre-coating the soft mold (20) 151 and 152, and the coating rolls 150, 151 and 152 are supplied with the coating liquid by the resin supply tanks 160, 161 and 162. The soft mold first coated by the preliminary coating unit A is rotated by the master roll and transferred to the coating liquid injection device 110, and the second coating is performed.

However, the squeegee roll method has a small unit area in contact with the soft mold per squeegee roll, so that a plurality of squeegee rolls can be additionally installed to improve productivity. As a result, a large number of rolls can be used to increase the equipment and increase external exposure. There is a risk of external contamination during coating.

SUMMARY OF THE INVENTION An object of the present invention is to provide an optical sheet manufacturing apparatus and an optical sheet manufacturing method using the same, which can improve productivity when using a plurality of squeegee rolls by greatly improving the cross sectional area contacting the soft mold during precoating.

Another object of the present invention is to provide an optical sheet manufacturing apparatus and a method for manufacturing an optical sheet using the same without the need for additional equipment supplementation according to the use of a plurality of squeegee rolls.

Still another object of the present invention is to provide an optical sheet manufacturing apparatus and an optical sheet manufacturing method using the same, which can drastically lower the possibility of contamination on foreign materials.

Still another object of the present invention is to provide an optical sheet manufacturing apparatus capable of reducing production time (including maintenance and cleaning time) and an optical sheet manufacturing method using the same.

Still another object of the present invention is to provide an optical sheet manufacturing apparatus and an optical sheet manufacturing method using the same, which can improve quality due to excellent bubble removal.

The technical objects to be achieved by the present invention are not limited to the above-mentioned technical problems, and other technical subjects which are not mentioned can be understood by those skilled in the art from the following description.

One aspect of the present invention relates to an optical sheet manufacturing apparatus. The manufacturing apparatus includes a soft mold in which a pattern is formed; A master roll in contact with the soft mold and laminating the soft mold and the base film into which the coating liquid is injected; A first roll engaged with the master roll to press the soft mold and the base film into which the coating liquid is injected; A second roll separating the laminated film from the first roll into an optical film having a soft mold and a pattern formed thereon; And a pre-coating unit for precoating the soft mold transferred from the second roll, wherein the pre-coating unit transfers the transferred soft mold to the main coating unit. And a coating roll for precoating the soft mold by rotation by receiving the coating liquid by a resin supply tank, wherein the guide roll and the coating roll are arranged in a zigzag without interlocking with each other.

In one embodiment, the coating roll may rotate in the same direction as the direction of rotation of the guide roll.

In another embodiment, the coating roll may rotate in a direction opposite to the direction of rotation of the guide roll.

The guide roll is at least two.

In one embodiment, the guide roll includes a first guide roll and a second guide roll adjacent to each other, the coating roll may be located between the first guide roll and the second guide roll.

In an embodiment, a hardening means may be further included between the first roll and the second roll.

In an embodiment, the optical sheet manufacturing apparatus may further include a tension control roll for adjusting the tension of the film to be transferred.

The present invention can greatly improve the cross-sectional ratio of contact with the soft mold during the pre-coating can improve the productivity when using a plurality of squeegee rolls, do not need additional equipment supplements according to the use of a plurality of squeegee rolls and can be filled with a smooth solution In addition, the possibility of contamination on foreign materials can be drastically lowered, the production time (including maintenance and cleaning time) can be reduced, and the optical sheet manufacturing apparatus and the optical sheet manufacturing using the same can improve the quality by excellent bubble removal. It has the effect of the invention providing a method.

1 is a schematic diagram of a conventional optical sheet manufacturing apparatus.
Figure 2 is a schematic diagram of an optical sheet manufacturing apparatus according to an embodiment of the present invention.
Figure 3 (a) is a specific example of the coating roll to rotate in the running direction of the soft mold, (b) is a specific example of the coating roll to rotate in the reverse driving direction of the soft mold.
Figure 4 (a) is an embodiment of the pre-coating portion according to an embodiment of the present invention, (b) is an embodiment of the pre-coating portion according to another embodiment of the present invention.
Figure 5 compares the contact area according to the conventional squeegee roll method and the method of the present invention.
6 is an optical micrograph of the optical sheet prepared in Example 1.
7 is an optical micrograph of the optical sheet prepared in Example 2.
8 is an optical micrograph of the optical sheet prepared in Comparative Example 1.
9 is an optical micrograph of the optical sheet prepared in Comparative Example 2.

Figure 2 is a schematic diagram of an optical sheet manufacturing apparatus according to an embodiment of the present invention. As shown, the soft mold 20 is rotated in contact with the master roll 100. The soft mold 20 is a pattern is formed, the material is usually a resin material is used. The shape of the pattern is not particularly limited, and various patterns commonly applied to the optical sheet are possible. For example, a hemispherical microlens pattern, a lenticular pattern, a prism pattern, a semi-ellipse pattern, an irregular concave-convex pattern, or the like may be used, but is not limited thereto.

The soft mold 20 may be in contact with the entire master roll 100 or only a part of the master roll 100, and may rotate in contact with another guide roll or a tension control roll to facilitate rotation.

As the soft mold 20 rotates along the outer circumference of the master roll 100, the coating liquid is filled in the pattern. In the present invention, after the coating is pre-coated in the pre-coating portion (A) to remove the air bubbles is performed in the main coating.

In the prior art, a squeegee roll was provided in the precoating portion, and precoating was performed by compression between rolls. In the present invention, the guide roll and the coating roll to the pre-coating portion (A) is arranged in a zigzag without interlocking with each other and pre-coated.

In a specific embodiment, the pre-coating portion (A) of the present invention comprises a guide roll (140, 141, 142) and the coating roll (150, 151). The guide rolls 140, 141 and 142 serve to transfer the transferred soft mold to the main coating part. The coating rolls 150 and 151 are supplied with the coating liquid by the resin supply tanks 160 and 161 to precoat the soft mold by rotation. In FIG. 2, the number of guide rolls is illustrated as three, but is not limited thereto. In embodiments, the guide roll of the pre-coating portion (A) may be two or more. For example, about 2 to 5 guide rolls may be formed. The guide rolls 140, 141, and 142 guide the soft mold 20 to which the pre-coating is completed and at the same time to impart proper tension to the soft mold 20.

The coating rolls 150 and 151 may be formed between the guide rolls so as not to engage with the guide rolls. Guide rolls 140, 141 and 142 are arranged on one side and coating rolls 150 and 151 are alternately arranged on the other side, and the soft mold is linear as shown in FIG. 4 (a). 4B, the centers of the guide rolls 140, 141 and 142 and the coating rolls 150 and 151 are arranged in the same line, so that the soft molds are zigzag. Can be transported. The positions of the guide rolls 140, 141 and 142 and the coating rolls 150 and 151 are appropriately designed to maximize the contact area of the coating rolls in consideration of these sizes.

In embodiments, the coating roll may be rotated in the same direction as the rotation direction of the guide roll or in the opposite direction. Figure 3 (a) shows that the rotational direction of the coating roll and the guide roll is the opposite direction (coating roll rotation direction is the running direction of the soft mold), Figure 3 (b) is the rotational direction of the coating roll and the guide roll It is shown that it is the same direction (coating roll rotation direction of the reverse direction of the soft mold). As such, by adjusting the rotation direction and speed of the coating roll, the coating roll may further increase the contact surface with respect to the soft mold. Therefore, even if the number of coating rolls is not increased, it is possible to obtain the effect of improving productivity while sufficiently coating the crude liquid on the mold surface. It becomes possible.

5 compares the contact area of a conventional squeegeeing scheme (a) with the inventive scheme (b). As shown in Figure 5, when the coating roll is arranged in a zigzag form between the guide roll it can be seen that the contact area is increased compared to the squeegee method in which the coating roll and the guide roll is engaged with each other.

As such, the soft mold 20 coated by the preliminary coating part A is transferred to the coating liquid injection device 110 which is the main coating part while being rotated by the master roll 100 and then coated with a secondary coating. The secondary coating is made while the coating liquid is injected by the coating liquid injection device (110). The injection position of the coating liquid in the secondary coating, which is the main coating, is not particularly limited, but is usually injected before lamination with the base film 10. The coating liquid injection device 110 constitutes the main coating portion, it can be easily installed by those skilled in the art to which the present invention belongs. In addition, the coating liquid and the coating liquid during the main coating described above are well known by those skilled in the art to which the present invention belongs.

The soft mold 20 in which the main coating is completed by the coating liquid injection device 110 is laminated with the base film 10. In one embodiment, the first roll 120 is formed to be engaged with the master roll 100 and pressed by the first roll 120 to be laminated.

The size, spacing and degree of pressurization of the first roll 120 can be easily implemented by those skilled in the art to which the present invention pertains.

The laminated film 11 has a structure in which the soft mold 20 and the base film 10 are laminated through a coating liquid. The laminated film 11 is cured while being transported along the master roll 100. Although not shown in the drawings, the laminated film 11 may be provided with a separate curing means before separation. The curing means may be heat or ultraviolet rays, etc. The curing means may be easily installed by those skilled in the art to which the present invention pertains. In a specific embodiment, the hardening means may be formed between the first roll 120 and the second roll 130.

The cured film is separated into a soft mold 20 and an optical film 12 having a pattern. The patterned optical film 12 is composed of a cured layer of the coating solution cured on the base film 10, the cured layer is a pattern formed by transferring the pattern formed on the soft mold 20 was laminated have. The optical film 12 having the pattern formed as described above may be wound into a conventional method and manufactured as a product.

When the cured film is separated into the soft mold 20 and the optical film 12 having the pattern, the second roll 130 may be formed and separated. In a specific example, the second roll 130 may be installed to be in contact with the soft mold 20 to be transferred to the preliminary coating unit A. Installation of the second roll 130 can be easily carried out by those skilled in the art to which the present invention belongs.

The soft mold 20 separated from the second roll 130 is transferred to the pre-coating portion A again to repeat the process.

Optical sheet manufacturing apparatus of the present invention may further include a tension control roll (not shown) for adjusting the tension of the film to be transferred. For example, it may be formed between the second roll 130 and the guide roll 140 or between the guide roll 142 and the master roll 100, and the installation of the tension adjusting roll is common knowledge in the field to which the present invention belongs. It can be easily carried out by a person having.

Another aspect of the invention relates to a method of manufacturing an optical sheet.

The method includes precoating the soft mold in a precoating section arranged in a zigzag without engaging the guide roll and the coating roll with each other; Transferring the precoated soft mold to a main coating part to inject a coating solution; Laminating the base film to the soft mold into which the coating liquid is injected; Separating the laminated film into a soft mold and an optical film having a pattern formed thereon; The soft mold may include the step of transferring the pre-coating unit and pre-coating again.

The pre-coating portion guide roll for transferring the transferred soft mold to the main coating portion; And a coating roll receiving the coating liquid by a resin supply tank and precoating the soft mold by rotation.

In embodiments, the method may further include curing the laminated film before separating the optical film.

Hereinafter, the configuration and operation of the present invention through the preferred embodiment of the present invention will be described in more detail. It is to be understood, however, that the same is by way of illustration and example only and is not to be construed in a limiting sense.

Details that are not described herein will be omitted since those skilled in the art can sufficiently infer technically.

Example  One

As a base film, a PET film (A4300 PET film thickness of 250 μm from TOYOBO, Japan) was used, and a soft mold in which a microlens pattern was formed of the same material was applied. Using the UV curable acrylic resin (S-001, Natoco, Japan) as a coating liquid was prepared an optical film using the apparatus as shown in FIG. At this time, the soft mold feed speed was 10 m / min and the coating roll rotation direction was rotated in the same direction as the running direction of the soft mold (as opposed to the guide roll direction). For the optical film produced, a pattern was taken at 600 times magnification using an optical microscope (SOMETECH, ICAMSCOPE SV32), and the photograph is shown in FIG. 6.

Example  2

The coating roll rotation direction was performed in the same manner as in Example 1 except that the coating roll rotation direction was rotated in the direction opposite to the traveling direction of the soft mold (the same as the guide roll direction). An optical micrograph of the pattern is shown in FIG. 7.

Comparative Example  One

As a base film, a PET film (A4300 PET film thickness of 250 μm from TOYOBO, Japan) was used, and a soft mold in which a microlens pattern was formed of the same material was applied. Using an UV curable acrylic resin (S-001, Natoco, Japan) as a coating liquid was prepared an optical film using the apparatus as shown in FIG. At this time, the soft mold feed rate was 5 m / min. The prepared optical film was photographed at 600 times magnification using an optical microscope (SOMETECH, ICAMSCOPE SV32), and the photograph is shown in FIG. 8.

Comparative Example  2

The soft mold feed rate was changed to 10 m / min and the same as in Comparative Example 1 except that the number of guide rolls and coating rolls was increased to four. The optical micrograph of the pattern is shown in FIG. 9.

L / S (m / min) Coating roll number Example 1 10 2 Example 2 10 2 Comparative Example 1 5 3 Comparative Example 2 10 4

As shown in Figures 6 to 9, Example 1-2 is almost no bubble is formed, Comparative Example 1 can be seen that the bubble is formed, Comparative Example 2 to increase the mold transfer speed is formed a lot of bubbles You can see that.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. It is therefore to be understood that the embodiments described above are in all respects illustrative and not restrictive.

10: base film 20: soft mold
100: master roll 120: first roll
130: second roll 140, 141, 142: guide roll
150, 151, 152: coating rolls 160, 161, 162: resin supply tank

Claims (7)

A soft mold in which a pattern is formed;
A master roll in contact with the soft mold and laminating the soft mold and the base film into which the coating liquid is injected;
A first roll engaged with the master roll to press the soft mold and the base film into which the coating liquid is injected;
A second roll separating the laminated film from the first roll into an optical film having a soft mold and a pattern formed thereon; And
A pre-coating unit for pre-coating the soft mold transferred from the second roll;
It comprises, wherein the pre-coating portion guide roll for transferring the transferred soft mold to the main coating portion; And a coating roll for precoating the soft mold by rotation by receiving the coating liquid by a resin supply tank,
The coating roll and the guide roll are each at least two,
The guide roll and the coating roll are arranged in a zigzag without engaging each other,
Optical sheet manufacturing apparatus, characterized in that the center of the guide roll and the coating roll is arranged to be formed on the same line.
The optical sheet manufacturing apparatus of claim 1, wherein the coating roll is rotated in the same direction as the rotation direction of the guide roll.
The optical sheet manufacturing apparatus of claim 1, wherein the coating roll is rotated in a direction opposite to the direction of rotation of the guide roll.
delete The optical sheet according to claim 1, wherein the guide roll includes a first guide roll and a second guide roll adjacent to each other, and a coating roll is positioned between the first guide roll and the second guide roll. Manufacturing equipment.
The optical sheet manufacturing apparatus of claim 1, further comprising a hardening means between the first roll and the second roll.
The optical sheet manufacturing apparatus of claim 1, wherein the optical sheet manufacturing apparatus further comprises a tension adjusting roll for adjusting the tension of the film to be transferred.

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