KR102328501B1 - How to cut a film - Google Patents

Abstract

A method for cutting a film by laser light while preventing cracks in the film is provided. The film cutting method of the present invention includes cutting out a film including a polarizer by laser light irradiation, and forming a cut-out portion of a predetermined shape on the film, at the starting point of cutting by laser light irradiation. The angle between the tangent line A of the cut-out portion or the side B of the cut-out portion including the starting point and the absorption axis of the polarizer is 0° to 85° or 95° to 180°.

Description

How to cut a film

The present invention relates to a method for cutting a film. More particularly, the present invention relates to a method for cutting a film using laser light.

Conventionally, although a polarizing plate is used for an image display apparatus etc., with the diversification of the use of an image display apparatus, the shape of the polarizing plate used for the said image display apparatus is also diversifying in recent years. For example, in an automobile image display apparatus (for example, an image display apparatus used for an instrument panel), a polarizing plate etc. which cut out into a predetermined shape and have a cutout part etc. are used.

In general, as one of the means for cutting a film, laser light irradiation is known. However, in the polarizing plate containing the polarizer obtained through the extending process, there exists a problem that a crack is easy to produce with the starting point and the end point of laser beam irradiation as a starting point.

Japanese Patent Application Laid-Open No. 2005-326831

The present invention has been made in order to solve the above-mentioned conventional problems, and its main object is to provide a method for cutting a film by laser light while preventing cracks in the film.

The cutting-out method of the film of this invention includes cutting out the film containing a polarizer by laser light irradiation, and forming a cut-out part of a predetermined shape in the said film, At the cutting-out starting point by the said laser light irradiation The angle between the tangent line (A) of the cut-out portion of , or the side (B) of the cut-out portion including the starting point and the absorption axis of the polarizer is 0° to 85° or 95° to 180°.

In one embodiment, the angle between the tangent line A or the side B and the absorption axis of the polarizer is 0° to 60° or 120° to 180°.

In one embodiment, the said tangent line A or the side B, and the absorption axis of a polarizer are parallel.

ADVANTAGE OF THE INVENTION According to this invention, a film can be cut out by a laser beam, preventing the crack of a film by making the clipping start point by laser beam irradiation into a specific position.

1(a) and 1(b) are views for explaining a method for cutting a film according to an embodiment of the present invention.
It is a figure explaining the cutting-out method of the film which concerns on another embodiment of this invention.

The cutting-out method of the film of this invention includes cutting out the film containing a polarizer by laser light irradiation, and forming the cut-out part of a predetermined shape in the said film.

A polarizer single-piece|unit may be sufficient as the film containing a polarizer, and the film containing a polarizer (preferably one polarizer) and another layer may be sufficient as it. As another layer, the protective layer which protects a polarizer, the layer comprised from arbitrary suitable optical films, etc. are mentioned. In one embodiment, a polarizing plate is used as a film containing a polarizer. The polarizing plate may include a polarizer and a protective layer disposed on at least one side of the polarizer. Moreover, you may use the laminated body of a polarizing plate, a surface protection film, and/or a separator as a film containing a polarizer. A surface protection film or a separator is laminated|stacked so that peeling is possible on a polarizing plate through arbitrary appropriate adhesives. As used herein, the term "surface protection film" is a film that temporarily protects the polarizing plate, and is different from the protective layer (layer that protects the polarizer) included in the polarizing plate.

The polarizer is typically a resin film (eg, polyvinyl alcohol-based resin film) with swelling treatment, stretching treatment, dyeing treatment with a dichroic substance (eg, iodine, organic dye, etc.), crosslinking treatment, washing treatment, drying treatment, etc. It is obtained by performing various treatments of Generally, although the polarizer obtained through an extending|stretching process has the characteristic that a crack is easy to produce, according to this invention, a film can be cut out, preventing a crack.

The thickness of the film including the polarizer is not particularly limited, and an appropriate thickness may be employed depending on the purpose, for example, 20 µm to 200 µm. The thickness of the polarizer is also not particularly limited, and an appropriate thickness may be employed depending on the purpose. The thickness of the polarizer is typically about 1 µm to 80 µm, and preferably 3 µm to 40 µm.

The size of the film including the polarizer is not particularly limited, and may be an appropriate size depending on the purpose. In one embodiment, the film containing a polarizer is a rectangular shape or square shape including the side parallel to the absorption axis of a polarizer, the length of the side parallel to the absorption axis of a polarizer is 10 mm - 400 mm, The length of the other side is 10 mm to 500 mm.

1(a) and 1(b) are views for explaining a method for cutting a film according to an embodiment of the present invention. In Fig.1 (a), the film 100 containing the polarizer at the time of starting cutting by laser beam irradiation, ie, the time of irradiating a laser beam to the cutting-out starting point 11 is shown. In FIG.1(b), the film after the cut-out by laser beam irradiation is complete|finished, ie, the film 110 which has the cut-out part 10 is shown. In the present embodiment, first, the laser beam is irradiated to the cutting starting point 11, and then, the laser beam is continuously irradiated to the outer edge 12 of the part to be cut. Film 100 including a polarizer cut out, and a substantially circular cut-out portion 10 is formed on the film.

When the cutting-out starting point 11 is on a curve (for example, in the case of embodiment shown in FIG. 1), the tangent line A of the cutting-out part at the cutting-out starting point 11 by laser light irradiation and the polarizer The angle formed by the absorption axis X is 0° to 85° or 95° to 180°, preferably 0° to 60° or 120° to 180°, more preferably 0° to 45° or 135 ° to 180 °, particularly preferably 0 ° to 30 ° or 150 ° to 180 °. Most preferably, the tangent (A) and the absorption axis (X) are parallel. In the present specification, "parallel" includes the case where they are substantially parallel, and specifically includes the case where the angle between the two directions is 0° to 5°. In addition, when referring to an angle in this specification, unless otherwise indicated, the said angle includes the angle of both a clockwise direction and a counterclockwise direction.

When the shape of the cut-out portion is substantially circular, the diameter can be any suitable length depending on the use of the film. The diameter is, for example, 2 mm to 100 mm. According to the present invention, it is also possible to cut out a cut-out portion having a small diameter by preventing cracks. For example, a substantially circular cutout having a diameter of 2 mm to 50 mm (preferably 2 mm to 10 mm) can be formed to prevent cracks.

2 is a view for explaining a method for cutting a film according to another embodiment of the present invention. In FIG. 2, the film containing the polarizer at the time of starting the cutting by laser beam irradiation, ie, the time of irradiating a laser beam to the cutting-out starting point 11' is shown. In this embodiment, a film containing a polarizer is first irradiated with laser light at the cutting start point 11', and then continuously irradiated to the outer 12' of the portion to be cut with the laser light. It cuts out, and the cut-out part of a substantially rectangular shape is formed in the said film. As illustrated in FIG. 2 , when the clipping starting point is on a straight line, the angle between the side B including the clipping starting point 11 ′ and the absorption axis X of the polarizer is 0° to 85 ° or 95 ° to 180 °, preferably 0 ° to 60 ° or 120 ° to 180 °, more preferably 0 ° to 45 ° or 135 ° to 180 °, particularly preferably 0 ° to 30 ° or 150° to 180°. Most preferably, the side B and the absorption axis X are parallel. When the shape of the cut-out portion is a substantially rectangular shape, the short side thereof is preferably 2 mm to 100 mm, more preferably 2 mm to 50 mm, still more preferably 2 mm to 30 mm, and particularly preferably 2 mm to 10 mm. Further, the long side is preferably 5 mm to 400 mm, more preferably 5 mm to 200 mm, still more preferably 5 mm to 120 mm, particularly preferably 5 mm to 40 mm.

The shape of the cut-out part is not limited to the shape shown in FIGS. 1 and 2 . As a shape of a cutout part, in addition to a substantially circular shape and a substantially rectangular shape, a substantially square shape, a substantially elliptical shape, etc. are mentioned, for example. In addition, the shape of the cut-out part may be the shape which combined a straight line and a curve suitably, and the shape comprised with the several curve from which a curvature differs. When the periphery of the cut-out portion has a vertex and/or a connection point between a straight line and a curved line, it is preferable not to use the vertex and the connection point as the cutting starting point.

The area ratio of the cut-out portion is, for example, 10% to 50% with respect to the area of the film including the polarizer (film before cutting).

In this invention, the said film can be cut out with a laser beam, preventing the crack of the film containing a polarizer by making a clipping start point into the specific position as mentioned above. When forming a cut-out part of a predetermined shape with a laser beam, irradiation of a laser beam is started with a cut-out starting point as a starting point, and after forming a cut-out part, a laser beam returns to a cut-out starting point. That is, the starting point and the ending point of laser light irradiation become the same part. Therefore, at the starting point and ending point of the laser light irradiation, at the starting point of the cutting out, the cut-out portion is minute as shown in FIG. will have In this invention, it is thought that the crack of a film is prevented by making the said convex part which can become a clipping starting point, ie, the trigger of a crack, the said specific position with respect to the absorption axis of a polarizer as a reference. The film cut out by the method of the present invention has sufficient durability even against severe temperature changes (eg, heat cycle of -40°C to 85°C), and is hardly cracked.

The laser light preferably includes light having a wavelength of 200 nm to 11000 nm.

Any suitable laser can be employed as the laser used for laser light irradiation. For example, any suitable laser may be employed. Specific examples include _{gas lasers such as CO 2} laser and excimer laser; solid-state lasers such as YAG lasers; A semiconductor laser etc. are mentioned.

Any suitable conditions can be adopted as the irradiation conditions (output conditions, moving speed, number of times) of laser light according to the material of the film, the thickness of the film, and the like.

[Example]

Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited by these Examples.

[Example 1]

A laser beam was irradiated, and the circular cut-out part (20 mm in diameter) was cut out from the polarizer of 72 mm square. The angle between the tangent of the clipping portion at the clipping start point and the absorption axis of the polarizer was set to 0°. In addition, the distance between each side of a polarizer and the center of a cut-out part was made into 30 mm.

In addition, the irradiation conditions of a laser beam were carried out as follows.

Wavelength: 9.4 μm

Pulse width: 8㎲

Output: 10V

Frequency: 12.5kHz

Machining speed: 400mm/sec

[Example 2]

The polarizer was cut out in the same manner as in Example 1, except that the angle between the tangent of the cut-out portion at the start point of the clipping and the absorption axis of the polarizer was set to 30°.

[Example 3]

The polarizer was cut out in the same manner as in Example 1, except that the angle between the tangent of the cut-out portion at the starting point of the clipping and the absorption axis of the polarizer was 45°.

[Example 4]

The polarizer was cut out in the same manner as in Example 1, except that the angle between the tangent of the cut-out portion at the starting point of the clipping and the absorption axis of the polarizer was set to 60°.

[Comparative Example 1]

The polarizer was cut out in the same manner as in Example 1, except that the angle formed between the tangent of the cut-out portion at the start point of the clipping and the absorption axis of the polarizer was set to 90°.

[evaluation]

The polarizer which has the cut-out part obtained from the Example and the comparative example was used for the heat shock test. In the heat shock test, after placing in an environment of 85°C for 30 minutes, what was placed in an environment of -40°C for 30 minutes was set as 1 cycle, and the appearance of the polarizer after 200 cycles and 300 cycles was visually confirmed.

The heat shock test was performed on five samples to determine the crack occurrence rate (when none of the samples had cracks: 0%, when cracks occurred in five samples: 100%). A result is shown in Table 1.

[Table 1]

[Industrial Applicability]

The cutting-out method of the film of this invention is used preferably, when manufacturing optical films, such as a polarizing plate.

10: cut out part
11,11' : starting point of clipping
100: film

Claims (5)

Cutting out a film containing a polarizer by laser light irradiation, and forming a cut-out portion of a predetermined shape on the film,
In the laser light irradiation, laser light is irradiated to the cutting start point, and then, the laser light is continuously irradiated to the outside of the part to be cut out,
The angle between the tangent line (A) of the cut-out portion at the start point of the cut-out by laser light irradiation or the side (B) of the cut-out section including the start point and the absorption axis of the polarizer is 0° to 85° or 95° -180°,
When forming the cut-out portion, the cut-out start point and the end point by the laser light irradiation become the same part,
When the outline of the cut-out portion has a vertex and/or a connection point between a straight line and a curved line, the vertex and the connection point are not used as a cutting start point,
How to cut a film. According to claim 1,
The angle between the tangent line (A) or the side (B) and the absorption axis of the polarizer is 0° to 60° or 120° to 180°. According to claim 1,
A method of cutting a film in which the tangent line (A) or the side (B) and the absorption axis of the polarizer are parallel to each other. delete delete

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