TWI572910B - Protection film and polarizer plate using the same - Google Patents

Description

Protective film and polarizing plate using the same

The present invention relates to a protective film and a polarizing plate using the same, and particularly relates 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 the inspection, it is usually visually observed whether the polarizing film under the protective film has defects. However, the protective film is usually reflective, and the glare it produces hinders the eye's inspection of the polarizing film.

Therefore, there is a need to propose a new technology to improve the glare problem of conventional protective films.

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

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

According to another embodiment of the invention, a protective film is proposed. The protective layer has an axial angle and an X axis. Looking at the direction of the X-axis, the axial angle of the central region of the width of the protective layer is smaller than the axial angle of the end point of the protective layer.

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

In order to better understand the above and other aspects of the present invention, the preferred embodiments are described below, and in conjunction with the drawings, the detailed description is as follows:

10‧‧‧Polar 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 overlay

A1, A2‧‧‧ angle

S1‧‧‧ Curve

T1‧‧‧ thickness

X, Y, Z‧‧‧ coordinate axis

W1‧‧‧Width

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

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

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

Please refer to FIG. 1 , which illustrates a schematic view of a protective film 100 in accordance with 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 axial angle and thus can produce low glare characteristics. As shown by the relationship S1 between the width W1 of the protective layer 110 and the axial angle 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, which causes the protective film 100 to have a low glare effect and can reduce the rainbow ripple phenomenon. In another embodiment, the predetermined angle A1 may be lower than 15 degrees or lower. The shaft angle here refers to the slow phase axis of the protective layer 110 and The angle at which the protective layer 110 is sandwiched by the X-axis is also referred to as the slow axis.

In one embodiment, as seen in FIG. 1, the axial angle of the central region of the width W1 of the protective layer 110 of the embodiment of the present invention is smaller than the axial angle of the two end points of the protective layer 110 as viewed in the direction of the X-axis. In one embodiment, the difference in 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 axial angle of the protective layer 110 of the embodiment of the present invention is less than the predetermined angle A1, so that the full-width protective layer 110 raw material or the protective film 100 can be completely used without special consideration of the high axial angle at which the cutting edge does not meet the requirements. Part of the material, so there is no material loss problem (high shaft angle is prone to glare and / or rainbow lines), and can reduce the process steps and increase product yield.

In the present 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 the length extension direction of the protective layer 110, and the Z-axis direction may be the width direction of the protective layer 110. In the method of measuring the shaft angle, the protective layer 110 or the protective film 100 may be measured by an absorption axis angle measuring instrument. The model of the absorption shaft angle measuring instrument is, for example, the model PLS-2R.

In an embodiment, the thickness T1 of the protective film 100 is, for example, between 12 micrometers and 250 micrometers. Further, the protective layer 110 may be a polyester resin, an olefin resin, a cellulose acetate resin, a polycarbonate resin, an acrylic resin, a polyethylene terephthalate (PET), a polyethylene (PE) or a poly Propylene (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).

Further, a surface treatment layer may be formed on the protective layer 110 of the protective film 100, for example, an antifouling layer for preventing surface contamination, an antistatic layer for preventing an electrostatic effect on the surface, a hard coat layer for preventing scratches, and the like. The above antistatic layer is, for example, (a) various cationic antistatic agents having a cationic group such as a quaternary ammonium salt, a pyridinium group, a primary amino group, a secondary amino group or a tertiary amino group; (b) having a sulfonic acid base and a sulfate base An anionic antistatic agent such as an anion group such as a phosphate base or a phosphonic acid base; (c) an amphoteric antistatic agent such as an amino acid or an aminosulfate; (d) an amino alcohol, a glycerin or a polyethylene a nonionic antistatic agent such as an alcohol; (e) a polymer type antistatic agent obtained by polymerizing the antistatic agent as described above.

In another embodiment, the surface may be modified by corona discharge technology on the surface of the protective layer 110 to increase the adhesion between the adhesive layer 120 and the protective layer 110. Alternatively, an easy subsequent chemical treatment can be performed on the protective layer 110 to facilitate the adhesion of the adhesive layer 120 to the protective layer 110, and the amount of residual glue can be reduced or even avoided.

Further, the adhesive layer 120 may be made of a material such as a (meth)acrylic copolymer, for example, a material which may include, but is not limited to, a functional group such as methyl (meth) acrylate or ethyl (meth) acrylate, A material such as butyl methacrylate or 2-ethylhexyl (meth)acrylate.

2 is a schematic view of a polarizing plate 10 according to an embodiment of the invention. Figure. The polarizing plate 10 includes a protective film 100 and a polarizing film 200, wherein the protective film 100 is disposed on the polarizing film 200. In one embodiment, the protective film 100 may be appropriately sized and attached to the polarizing film 200 to form the polarizing plate 10.

The polarizing film 200 includes a first cover layer 210 , a polarizing layer 220 , and a second cover layer 230 , wherein the polarizing layer 220 is formed between the first cover layer 210 and the second cover 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 formed by adsorbing a polyvinyl alcohol (PVA) film of an aligning dichroic dye or by absorbing a dye molecule with a liquid crystal material. Polyvinyl alcohol can be formed by saponifying polyvinyl acetate. In some embodiments, the polyvinyl acetate may be a monomer of vinyl acetate or a copolymer of vinyl acetate and other monomers, and the like. The above other monomers may be unsaturated carboxylic acids, olefins, unsaturated sulfonic acids or vinyl ethers. In other embodiments, the polyvinyl alcohol may be a modified polyvinyl alcohol, for example, an aldehyde-modified polyethylene formaldehyde, polyvinyl acetal or polyvinyl butyral or 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 (Polymethylmethacrylate). Polyethylene Terephthalate (PET), Polypropylene (PP), Cyclo Olefin Polymer (COP), Polycarbonate (PC), or any combination of the above.

As shown in FIG. 2, the polarizing layer 220 of the polarizing film 200 underneath is inspected by the protective film 100 at an angle A2 of the eye, and 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 if the polarizing plate 10 is observed at an oblique angle, the protective film 100 does not cause excessive glare or even glare, so that the eyes can be clearly observed. The quality condition 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%; thus the protective film 100 may be Has excellent light transmission.

The peeling force of the protective film 100 on the polarizing film 200 (for example, the first covering layer 210 thereof) may be between 0.02 Newtons (N) / 25 mm (mm) to 0.3 N / 25 mm, preferably 0.03 N / Between 25 mm and 0.2 N/25 mm, preferably between 0.04 N/25 mm and 0.15 N/25 mm; thus, after the polarizing plate 10 is attached to the substrate, the protective film 100 is easily peeled off from the polarizing film 200. . Further, 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 is electrically charged to the peeling of 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 protection film 100 and/or polarizing film 200.

Fig. 3 is a schematic view showing a protective film 100' according to another embodiment of the present invention. In this embodiment, the protective film 100' includes a release layer 130 in addition to the protective layer 110 and the adhesive layer 120, wherein the adhesive layer 120 is formed on the protective layer 110. Between the release layer 130 and the release layer 130, the release layer 120 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 protective film 100 ′ is disposed on the polarizing film 200 (the polarizing film 200 is shown in FIG. 2 ), the release layer 130 is first peeled off from the adhesive layer 120 to expose the adhesive layer 120 , so that the adhesive layer 120 can be bonded to the adhesive layer 120 . On the polarizing film 200.

Further, 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, an anthracene resin. Further, in the method of measuring the shaft angle, the protective layer 110 or the protective film 100' may be measured by an absorption shaft angle measuring instrument.

In summary, the protective layer of the embodiment of the present invention has a low axial angle, and thus the protective film has excellent characteristics such as low glare, low rainbow pattern or even no glare or no rainbow pattern. In this way, even if the polarizing plate is observed at an oblique angle, the protective film does not cause excessive glare or even glare, so that the eye can clearly observe the quality of the polarizing film under the protective film.

In conclusion, the present invention has been disclosed in the above preferred embodiments, and is not intended to limit the present invention. A person skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, the scope of the invention is defined by the scope of the appended claims.

100‧‧‧Protective film

110‧‧‧Protective layer

120‧‧‧Adhesive layer

A1‧‧‧ angle

S1‧‧‧ Curve

X, Y, Z‧‧‧ coordinate axis

T1‧‧‧ thickness

W1‧‧‧Width

Claims (10)

A protective film comprising: a protective layer having an axial angle between 0 degrees and 20 degrees, wherein the protective layer further has an X-axis and a slow-phase axis, and the axial angle is the late-phase axis and the An angle formed by the X-axis; wherein the X-axis is the length direction or the width direction of the protective layer, and the difference of the axial angles of any two points of the protective layer is less than 20 degrees. A protective film comprising: a protective layer having an axial angle and an X-axis; wherein, viewed in the direction of the X-axis, the central angle of the width of the protective layer is less than the second end of the protective layer The axis angle; wherein the difference between the axis angles of any two points of the protective layer is less than 20 degrees. The protective film according to claim 1 or 2, wherein the material of the protective layer is selected from the group consisting of a polyester resin, an olefin resin, a cellulose acetate resin, a polycarbonate resin, an acrylic resin, and a polybutylene terephthalate. Polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), cyclic olefin resin or a combination thereof, wherein the polyester resin is polyethylene terephthalate or polynaphthalene Ethylene formate, and the acrylic resin is polymethyl methacrylate (PMMA). The protective film according to claim 1 or 2, further comprising: an adhesive layer formed on the protective layer; wherein the adhesive layer is made of a material of a (meth)acrylic copolymer; and/ Or the surface impedance of the adhesive layer is less than 10 ¹² Ω/□. The protective film of claim 1 or 2, wherein the protective layer has a surface treatment layer; and/or the protective layer is modified by a corona discharge technique; and/or the protective layer is easily chemically treated And/or the surface resistivity of the protective layer is less than 10 ¹¹ Ω/□; and/or the protective film has a haze of 0.5% to 10%. The protective film according to claim 5, further comprising: a release layer covering the adhesive layer. The protective film of claim 1 or 2, wherein the protective film has a thickness of between 12 micrometers and 250 micrometers. A polarizing plate comprising: a polarizing film; and the protective film according to any one of claims 1 to 7, which is disposed on the polarizing film. The polarizing plate of claim 8, wherein the polarizing film comprises: a first covering layer; a second covering layer; and a polarizing layer formed on the first covering layer and the second covering layer between. The polarizing plate of claim 8, wherein the protective film has a peeling force to the polarizing film of between 0.02 Newtons (N) / 25 mm (mm) to 0.3 N / 25 mm; and / or the protection The peeling charge amount of the film to the polarizing film is less than 3 kV (kV).