TW201809743A - Protection film and polarizer plate using the same - Google Patents

Abstract

A protection film and a polarizer plate using the same are provided. The protection film includes a protection layer. The protection layer has an axis-angle ranging between 0 degrees and 20 degrees. The protection layer further has an X axis and a slow axis, wherein the axis-angle is the angle included between the slow axis and the X axis.

Description

Protective film and polarizing plate using same

The invention relates to a protective film and a polarizing plate using the same, and more particularly to a protective film having a low axial angle and a polarizing plate using the same.

A conventional polarizing plate includes a polarizing film and a protective film, and the protective film is formed on the polarizing film. In inspection, it is usually observed visually whether the polarizing film under the protective film has defects. However, the protective film usually reflects light, and the glare generated by the protective film prevents the eye from inspecting the polarizing film.

Therefore, a new technology is urgently needed to improve the glare problem of the conventional protective film.

Therefore, the present invention provides a protective film and a polarizing plate using the same, which can improve the conventional problems.

According to an embodiment of the present invention, a protective film is provided. The protective film includes a protective layer. The protective layer has an axis angle between 0 degrees and 20 degrees, wherein the protective layer has an X axis and a late phase axis, and the axis angle is an angle formed by the late phase axis and the X axis.

According to another embodiment of the present invention, a protective film is provided. The protective layer has an axis angle and an X axis. Looking at the X axis, the axis angle of the central region of the width of the protective layer is smaller than the axis angle near the two end points of the protective layer.

According to another embodiment of the present invention, a polarizing plate is provided. The polarizing plate includes a polarizing film and the above-mentioned protective film. The protective film is disposed on the polarizing film.

In order to have a better understanding of the above and other aspects of the present invention, preferred embodiments are described below in detail with the accompanying drawings, as follows:

10‧‧‧ polarizing plate

100, 100’‧‧‧ protective film

110‧‧‧ protective layer

120‧‧‧ Adhesive layer

130‧‧‧ release layer

200‧‧‧ polarizing film

210‧‧‧first cover

220‧‧‧polarizing layer

230‧‧‧second cover

A1, A2‧‧‧angle

S1‧‧‧ curve

T1‧‧‧thickness

X, Y, Z‧‧‧ Coordinate axes

W1‧‧‧Width

FIG. 1 is a schematic diagram of a protective film according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of a polarizing plate according to an embodiment of the present invention.

FIG. 3 is a schematic diagram of a protective film according to another embodiment of the present invention.

Please refer to FIG. 1, which illustrates a schematic diagram of a protective film 100 according to an embodiment of the present invention. The protective film 100 includes a protective layer 110 and an adhesive layer 120. The adhesive layer 120 is formed on the protective layer 110.

The protective layer 110 of the present invention has a low axis angle, and thus can generate low glare characteristics. As shown in the relationship curve S1 between the width W1 and the axial angle of the protective layer 110 shown in FIG. 1, the axial angle of the protective layer 110 is smaller than a predetermined angle A1. The predetermined angle A1 is, for example, between 0 and 20 degrees, so that the protective film 100 can have a low-glare effect and can reduce the rainbow phenomenon. In another embodiment, the predetermined angle A1 may be lower than 15 degrees or lower. The axis angle here refers to the relationship between the late phase axis of the protective layer 110 and the The angle formed by the X-axis direction of the protective layer 110 is also referred to as the slow axis here.

In an embodiment, as shown in FIG. 1, when viewed in the direction of the X axis, the axial angle of the central region of the width W1 of the protective layer 110 according to the embodiment of the present invention is smaller than the axial angle near the two ends of the protective layer 110. In one embodiment, the difference between the axial angles of any two points of the protective layer 110 is less than 20 degrees, less than 15 degrees, less than 10 degrees, or less than 5 degrees.

The axis angle of the protective layer 110 in the embodiment of the present invention is less than the predetermined angle A1, so the full-width protective layer 110 raw material or the finished product of the protective film 100 can be used completely without special consideration to remove the high axis angle where the edges do not meet the requirements Part of the material, so no material loss problem (high axis angle is prone to glare and / or rainbow pattern), and can reduce the process steps and increase product yield.

In this embodiment, the X-axis direction is, for example, the width direction of the protective layer 110, and the Z-axis direction is the length extension direction of the protective layer 110. In another embodiment, the X-axis direction may be a length extension direction of the protective layer 110, and the Z-axis direction may be a width direction of the protective layer 110. In the method of measuring the angle of the shaft, the absorption layer angle measuring instrument can be used to measure the protective layer 110 or the protective film 100. The model of the absorption axis angle measuring instrument is, for example, model PLS-2R.

In one embodiment, the thickness T1 of the protective film 100 is, for example, between 12 μm and 250 μm. In addition, the protective layer 110 may be made of polyester resin, olefin resin, cellulose acetate resin, polycarbonate resin, acrylic resin, polyethylene terephthalate (PET), polyethylene (PE), or polyethylene. Polypropylene (PP), cycloolefin A hydrocarbon resin or a combination thereof, wherein the polyester resin is, for example, polyethylene terephthalate or polyethylene naphthalate, and the acrylic resin is, for example, polymethyl methacrylate (PMMA).

In addition, a surface treatment layer may be formed on the protective layer 110 of the protective film 100, such as an antifouling layer that prevents surface contamination, an antistatic layer that prevents electrostatic effects on the surface, a hard coating layer that prevents scratches, and the like. The aforementioned antistatic layer is, for example, (a) various cationic antistatic agents having cationic groups such as quaternary ammonium salt, pyridinium, primary amino group, secondary amino group, and tertiary amino group; (b) having sulfonic acid bases and sulfate bases , Anionic antistatic agents such as anionic groups such as phosphate bases and phosphonic acid bases; (c) amphoteric antistatic agents such as amino acids and amino sulfates; (d) amino alcohols, glycerols, polyethylene glycols Nonionic antistatic agents such as alcohols; (e) Polymeric antistatic agents obtained by polymerizing the antistatic agents as described above.

In another embodiment, the surface of the protective layer 110 may also be modified by a corona discharge technique to increase the adhesion between the adhesive layer 120 and the protective layer 110. Alternatively, an easy-to-adhesive chemical treatment can be performed on the protective layer 110 to make the adhesive layer 120 easily adhere to the protective layer 110, and the amount of residual glue can also be reduced or even avoided.

In addition, the adhesive layer 120 may be made of a material such as a (meth) acrylic copolymer, such as a material that may include, but is not limited to, a functional group, such as methyl (meth) acrylate, ethyl (meth) acrylate, ( Materials such as butyl (meth) acrylate and 2-ethylhexyl (meth) acrylate.

FIG. 2 is a schematic diagram of a polarizing plate 10 according to an embodiment of the present invention. Illustration. The polarizing plate 10 includes a protective film 100 and a polarizing film 200. The protective film 100 is disposed on the polarizing film 200. In one embodiment, the protective film 100 may be cut to an appropriate size and then attached to the polarizing film 200 to form the polarizing plate 10.

The polarizing film 200 includes a first covering layer 210, a polarizing layer 220, and a second covering layer 230. The polarizing layer 220 is formed between the first covering layer 210 and the second covering layer 230. The protective film 100 is adhered to the first cover layer 210 of the polarizing film 200 through the adhesive layer 120, wherein the adhesive layer 120 is located between the first cover layer 210 and the protective layer 110.

The polarizing layer 220 may be a polyvinyl alcohol (PVA) film that adsorbs and aligns a dichroic pigment or is formed by mixing liquid crystal material with absorbing dye molecules. Polyvinyl alcohol can be formed by saponifying polyvinyl acetate. In some embodiments, the polyvinyl acetate may be a single polymer of vinyl acetate or a copolymer of vinyl acetate and other monomers. The other monomers may be unsaturated carboxylic acids, olefins, unsaturated sulfonic acids, vinyl ethers, and the like. In other embodiments, the polyvinyl alcohol can be modified polyvinyl alcohol, for example, aldehyde-modified polyvinyl formaldehyde, polyvinyl acetaldehyde, or polyvinyl butyral, and the like.

The material of the first cover layer 210 and the second cover layer 230 may be selected from the group consisting of triacetate cellulose (TAC), polymethylmethacrylate (PMMA), and polyethylene terephthalate ( A group consisting of Polyethylene Terephthalate (PET), Polypropylene (PP), Cyclo Olefin Polymer (COP), Polycarbonate (PC), or any combination thereof.

As shown in FIG. 2, the protective film 100 is used to inspect the polarizing layer 220 under the polarizing film 200 at a tilted angle A2 through the protective film 100. The angle A2 is, for example, 45 degrees, but may be greater than 45 degrees, such as 60 degrees Between 80 degrees, or less than 45 degrees, such as close to 0 degrees. Since the protective film 100 of the embodiment of the present invention has low glare characteristics or no glare characteristics, even when the polarizing plate 10 is viewed at an oblique angle, the protective film 100 does not generate excessive glare or even glare, so that the eyes can clearly observe The quality of the polarizing film 200 under the protective film 100.

In addition, the haze of the protective film 100 may be between 0.5% and 10%, preferably between 0.5% and 7%, and most preferably between 0.5% and 5%. Has excellent light transmission.

The peeling force of the protective film 100 from the polarizing film 200 (for example, the first cover layer 210) thereof may be between 0.02 Newton (N) / 25 millimeters (mm) and 0.3N / 25mm, preferably between 0.03N / Between 25mm and 0.2N / 25mm, preferably between 0.04N / 25mm and 0.15N / 25mm; in this way, after the polarizing plate 10 is attached to the substrate, the protective film 100 is easily removed from the polarizing film 200 . In addition, in terms of the antistatic ability of the protective film 100, the surface resistance of the protective layer 110 is less than 10 ¹¹ Ω / □, the surface resistance of the adhesive layer 120 is less than 10 ¹² Ω / □, and the adhesive layer 120 peels and charges the polarizing film 200. The amount is less than 3 kV (kV), preferably less than 1 kV, and most preferably less than 0.5 kV; this can reduce or even avoid electrostatic damage to the protective film 100 and / or polarizing film 200.

FIG. 3 is a schematic diagram of a protective film 100 'according to another embodiment of the present invention. In this embodiment, in addition to the protective layer 110 and the adhesive layer 120, the protective film 100 ′ further includes a release layer 130. The adhesive layer 120 is formed on the protective layer 110. And the release layer 130, and the release layer 130 covers the adhesive layer 120. Since the release layer 130 covers the adhesive layer 120, the adhesive layer 120 can be prevented from being exposed and self-adhesive or adhered to other objects. Before the release layer 130 is disposed on the polarizing film 200 (the polarizing film 200 is shown in FIG. 2), the release layer 130 is peeled off from the adhesive layer 120 to expose the adhesive layer 120 so that the adhesive layer 120 can be adhered on On the polarizing film 200.

In addition, the release layer 130 may be, for example, a polyethylene terephthalate film coated with a release agent on the surface, and the release agent is, for example, but not limited to, a silicone resin. In addition, in the method of measuring the shaft angle, the absorption layer 110 or the protective film 100 'can be measured by an absorption shaft angle measuring instrument.

In summary, it can be seen that the protective layer itself has a low axial angle, so the protective film has excellent characteristics such as low glare, low rainbow pattern, or even no glare or rainbow pattern. In this way, even if the polarizing plate is viewed at an oblique angle, the protective film does not generate excessive glare or even glare, so that the eyes can clearly observe the quality of the polarizing film under the protective film.

In summary, although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. Those with ordinary knowledge in the technical field to which the present invention pertains can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by the scope of the attached patent application.

100‧‧‧ protective film

110‧‧‧ protective layer

120‧‧‧ Adhesive layer

A1‧‧‧angle

S1‧‧‧ curve

X, Y, Z‧‧‧ Coordinate axes

T1‧‧‧thickness

W1‧‧‧Width

Claims (11)

A protective film includes: a protective layer having an axis angle between 0 degrees and 20 degrees, wherein the protective layer further has an X axis and a late phase axis, and the axis angle is the late phase axis and the The angle formed by the X axis. A protective film includes: a protective layer having an axis angle and an X axis; wherein, when viewed in the direction of the X axis, the axis angle of the central region of the width of the protective layer is smaller than two end points near the protective layer Its axis angle. The protective film according to item 1 or 2 of the scope of patent application, wherein the difference between the angles of the axes of any two points of the protective layer is less than 20 degrees. The protective film according to item 1 or 2 of the scope of patent application, wherein the material of the protective layer is selected from a polyester resin, an olefin resin, a cellulose acetate resin, a polycarbonate resin, an acrylic resin, and a polybutylene terephthalate. Diester (PET), polyethylene (PE), polypropylene (Polypropylene, PP), cycloolefin resin or a combination thereof, wherein the polyester resin is polyethylene terephthalate or polyethylene naphthalate Ethylene formate, and the acrylic resin is polymethyl methacrylate (PMMA). The protective film according to item 1 or 2 of the scope of patent application, further comprising: an adhesive layer formed on the protective layer; wherein the adhesive layer is made of a (meth) acrylic copolymer material; and / Or the surface impedance of the adhesive layer is less than 10 ¹² Ω / □. The protective film according to item 1 or 2 of the scope of patent application, wherein the protective layer has a surface treatment layer; and / or the protective layer is modified by corona discharge technology; and / or the protective layer is easily followed by chemical treatment ; And / or the surface resistance of the protective layer is less than 10 ¹¹ Ω / □; and / or the haze of the protective film is between 0.5% and 10%. The protective film according to item 5 of the scope of patent application, further comprising: a release layer covering the adhesive layer. The protective film according to claims 1 to 7, wherein the thickness of the protective film is between 12 microns and 250 microns. A polarizing plate includes: a polarizing film; and the protective film according to any one of claims 1 to 8 of the scope of patent application, which is disposed on the polarizing film. The polarizing plate according to item 9 of the scope of patent application, wherein the polarizing film package It includes: a first cover layer; a second cover layer; and a polarizing layer formed between the first cover layer and the second cover layer. The polarizing plate according to item 9 of the scope of patent application, wherein the peeling force of the protective film from the polarizing film is between 0.02 Newton (N) / 25 millimeter (mm) to 0.3N / 25mm; and / or the protection The peeling charge of the film to the polarizing film was less than 3 kV (kV).