JPH10268136A - Protection film and optical part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a protection film showing transparency for allowing the easy visual inspection of an inner optical element, having an indication mark substantially free from a change in thickness, and having the capability of easily forming and simply visualizing the mark. SOLUTION: This optical part is made of a phase difference film for covering adhesive layers 12 and 6 bonded to the surface of an optical element 5, and for being peeled from the optical element 5 independent of or together with the adhesive layers 12 and 6. In addition, the phase difference film has an indication mark formed in a zone having a partly different phase difference, thereby forming a protection film 7. This protection film 7 is bonded to the phase difference plate of the optical element 5 formed out of a compensation polarizing plate with a polarizing plate 2 and a phase difference plate 4 bonded and fixed, via the adhesive layer 6. Thus, the indication mark formed on the protection film can be visualized as a colored difference zone based on the different phase difference by visual recognition via the polarizing plate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a protective film having a display mark comprising a phase difference portion which can be visualized through a polarizing plate, and an optical component having the same.

[0002]

BACKGROUND ART An adhesive layer adhered to the surface of an optical material composed of a polarizing plate or a compensating polarizing plate having a retardation plate laminated thereon is coated and separated from the optical material independently of the adhesive layer or together with the adhesive layer. Protective films that have a transparent display mark indicating an optical axis such as an absorption axis, a slow axis, or a fast axis in an optical material are required.

In displaying a mark such as an optical axis, when a liquid crystal display device or the like is formed, it is required that the axial direction thereof be in a predetermined direction. That's why. Incidentally, in a compensating polarizing plate, especially in a compensating polarizing plate using a phase difference based on obliquely transmitted light that is asymmetrical in right and left and up and down as a retardation plate, optical characteristics in a right and left or up and down direction of a predetermined optical axis are different. In addition, right and left of the arrangement of the compensating polarizing plate are strictly regulated.

On the other hand, a requirement for a transparent mark is that an opaque mark formed by printing or the like cannot see the inside of the mark portion, so that the appearance of the optical material cannot be inspected while the protective film is adhered, and a printing section for forming the mark is required. This is because even if the thickness is about several μm, a problem such as a mark mark remaining on an optical material such as a polarizing plate occurs, and such a problem is avoided.

[0005]

SUMMARY OF THE INVENTION The present invention provides a display mark which shows transparency so that the internal optical material can be easily inspected for appearance and has substantially no thickness change, and which can be formed easily. The purpose is to develop a protective film that can be easily visualized.

[0006]

The present invention comprises a retardation film covering an adhesive layer adhered to the surface of an optical material and peeled from the optical material independently of or together with the adhesive layer. A protective film, wherein the film has a display mark, and the display mark is formed in a region where the retardation is partially different, and the protective film is a polarizing plate and a retardation plate An optical component characterized by being bonded to a retardation plate side of an optical material composed of a compensating polarizing plate to which is adhered and fixed via an adhesive layer.

[0007]

According to the protective film having the above-mentioned structure, the display mark formed on the protective film, which is formed by partially observing the phase difference by visual recognition through the polarizing plate, is formed as the color difference area based on the phase difference. Can be visualized.
Therefore, when applied to an optical material having a polarizing plate, visualization can be performed using the polarizing plate, and the use of a separate polarizing plate is unnecessary. In addition, since the mark is composed of a difference in phase difference, the difference is not recognized by the naked eye, and excellent transparency can be maintained, and the internal optical material can be easily and accurately inspected for appearance.
In addition, the formation of the mark does not involve a substantial change in thickness. Further, the retardation can be easily changed through a simple operation such as a heat treatment, and the display mark can be easily formed continuously on the long retardation film.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The protective film of the present invention comprises a retardation film which covers an adhesive layer adhered to the surface of an optical material and is separated from the optical material independently of or together with the adhesive layer, The retardation film has a display mark, and the display mark is formed in a region where the retardation is partially different.

FIG. 1 illustrates a protective film according to the present invention. 11 and 7 are protective films. Protective film 11
Is an optical material 5 having an adhesive layer 12 to be coated integrally.
When the protective film 11 is more peeled off, it is formed as an adhesive sheet 1 so that it can be peeled off together with the adhesive layer 12.
It is used to protect the surface of optical materials. On the other hand, the protective film 7 is formed as a separator so that when peeled from the optical material 5, the adhesive layer 6 to be coated can be independently peeled while being left on the optical material 5. It is used for the purpose of.

FIG. 1 shows an adhesive sheet 1 adhered to a polarizing plate side surface of an optical material 5 composed of a compensating polarizing plate in which a polarizing plate 2 and a retardation plate 4 are bonded and fixed via an adhesive layer 3. This shows a state in which a protective film 7 is adhered to the surface on the plate side via an adhesive layer 6 to form an optical component.

The protective films 11 and 7 are formed of a retardation film, and display marks are formed on the retardation film and are formed of regions where the retardation is partially different. When viewing the optical component from the polarizing plate side,
As shown in FIG. 2A, the display mark 71 provided on the protective film 7, which is visually recognized through the polarizing plate 2, develops a color different from the other portions based on the difference in the phase difference. It has become. Further, when viewed from the retardation plate side, the display mark 13 provided on the protective film 11 which is visually recognized through the polarizing plate 2 as shown in FIG. The color is different from the other parts.

Note that the display mark 71 in FIG.
It is formed by an arrow mark indicating a horizontal direction when bonding to a liquid crystal cell or the like, and upper and lower characters indicating a vertical direction. The display mark 13 in FIG. 2B is formed by an arrow mark indicating a reference direction such as an optical axis including an absorption axis or a transmission axis of the polarizing plate 2.

As the retardation film for forming the protective film, an appropriate retardation film exhibiting a retardation due to birefringence can be used. In general, a plastic film such as a uniaxial or biaxial film is used in view of strength and handling properties. A transparent film stretched by a method is used. From the viewpoint of controlling the retardation difference and the like, a stretched film having excellent retardation uniformity by, for example, aligning molecules as uniformly as possible is preferable. The thickness of the protective film can be appropriately determined according to the strength and the like.
~ 500 μm, especially 10-200 μm, especially 20-100
μm. Note that the protective film needs to be a transparent material having light transmittance, but need not be colorless.

As the plastic film forming the above-mentioned stretched film, any suitable one may be used without any particular limitation. In general, for example, polycarbonate and polyarylate, polysulfone and polyethylene terephthalate,
A film made of a thermoplastic polymer such as polyethylene naphthalate, polyimide, polyether sulfone, polyolefin, polystyrene, polyvinyl chloride, polyamide, acrylic resin, or acetate resin is used. The plastic film may be formed by an appropriate method such as an extrusion method.

The protective film used as a separator is provided with a coating layer made of a suitable release agent such as a silicone-based, long-chain alkyl-based, or fluorine-based, if necessary. The protective film used as the adhesive sheet may be subjected to a surface treatment such as a corona discharge treatment or a primer treatment, if necessary, for increasing the adhesion to the adhesive layer.

The formation of the region having a difference in retardation with respect to the retardation film can be performed by an appropriate method such as a method in which the orientation state of the polymer in the retardation film is partially changed by heat, a penetrating agent or the like. The preferred method from the viewpoint of the formation efficiency of the display mark and the like, using a heating or osmotic drug injection type printer such as a thermal transfer type or ink jet type, a laser processing machine, a heating type or osmotic drug application type stamp, etc. In this method, a predetermined display mark is directly provided by a writing method or the like. In these systems, complicated display marks can be easily and efficiently formed without problems such as dents.

Also, the display mark can be efficiently formed by a method of printing a penetrable drug through a mask as necessary. In particular, in a printing method using a mask, a process of making the phase difference different in a large area can be easily performed. Therefore, the heat and the penetrable drug can be applied by an appropriate method such as a heating method via a heat source, a method of applying heat via electric discharge, or a method of applying a medicine, and the application of heat and the drug can be performed. Both can also be used in combination.

When the phase difference is made different by the heat treatment in the above, it is preferable to heat the phase difference film to a temperature higher than the thermal deformation temperature (near the glass transition temperature), and to decrease the degree of molecular orientation by controlling the amount of heat (temperature × time). Can be adjusted. On the other hand, as the osmotic agent for making the retardation different, such as a solvent capable of dissolving or swelling the retardation film, it is possible to use an appropriate drug solution that can reduce the degree of molecular orientation, depending on the type of the agent By controlling the permeability such as solubility and swelling degree and controlling the degree of permeation by the treatment time, the degree of the phase difference due to the decrease in the degree of molecular orientation can be controlled.

According to the method using a thermal or / and osmotic agent, it is possible to easily obtain a continuous body of a protective film comprising a single-layer continuous film, and thus having a display mark having substantially no thickness change. . Also in the case of a crystalline retardation film, a process of making the retardation different when in an amorphous state is performed, and the film is stretched and heat-set to obtain a protective film having a display mark.

The display mark formed as the phase difference difference region is arbitrary and can be determined appropriately according to the purpose of use. Appropriate patterns such as identification marks and pictures may be formed by appropriately combining characters, figures, symbols, and the like, and may be used as display marks composed of sentences. Further, the display mark may be composed of an area where the phase difference is changed, or may be an area where the phase difference is not changed, that is, an area where the original retardation of the retardation film is left. The formation of the latter display mark may be performed by a method of masking the mark portion with a resist or the like and performing a phase difference processing, but in that case, the masking is removed after the processing to reduce the film thickness. It is preferable to achieve uniformity.

There is no particular limitation on the phase difference provided to the area where the display mark is formed. From the point of visualization of the display mark by coloring through the polarizing plate, it is more than 300 to
It is preferable to have a phase difference in the range of 700 nm. In the present invention, a display mark of two or more colors can be formed due to a difference in color development by providing two or more differences in the phase difference.

As described above with reference to FIG. 1, the protective film of the present invention comprises, as the separator 7 or the adhesive sheet 1, the adhesive layers 12, 6 adhered to the surface of the optical material 5,
It is covered with a display mark including a region having a different phase difference. Such a protective film can be provided on one or both of the front and back surfaces of the optical material, and when both are provided, a combination of separators or adhesive sheets can be used.

The optical material to which the protective film is adhered is not particularly limited, but for example, an absorption axis, a transmission axis,
A polarizing plate or a retardation plate having an optical axis such as a slow axis or a fast axis,
Optical materials such as a liquid crystal cell or a liquid crystal polymer film having a liquid crystal layer in which an alignment direction appears in molecules, or display marks in handling such as anisotropy in optical characteristics, such as a laminate of the above materials. The protective film of the present invention can be advantageously used for an optical material in which is desired.

In particular, as shown in FIG. 1, an optical material comprising a compensating polarizing plate in which a polarizing plate and a retardation plate are adhered and fixed, in particular, a retardation plate is disclosed in JP-A-6-75116 and JP-A-6-21.
No. 4116, etc., when the phase difference due to birefringence of the light obliquely transmitted through the phase difference plate shows an asymmetry on the left and right or up and down with respect to the normal line in the main refractive index direction. When the optical material has different optical characteristics in the left and right or up and down directions and is adhered to a liquid crystal cell or the like, the up and down and left and right directions of the optical material are regulated. It can be used particularly advantageously for materials.

In the above, there is no particular limitation on a polarizing plate, a retardation plate, a liquid crystal layer, an adhesive layer, etc., which form an optical material such as a compensating polarizing plate. Incidentally, as a polarizing plate, iodine and / or a dichroic dye may be used on a hydrophilic polymer film such as a polyvinyl alcohol-based film, a partially formalized polyvinyl alcohol-based film, an ethylene-vinyl acetate copolymer-based partially saponified film, and a cellulose-based film. Adsorbed and stretched, polyene oriented film such as dehydrated polyvinyl alcohol or dehydrochlorinated polyvinyl chloride, or transparent film laminating method or transparent resin coating method on one or both sides of the polarizing film And those having a transparent protective layer formed by an appropriate method.

Examples of the retardation plate include polycarbonate, polyester, polysulfone and polyethersulfone, polyolefins such as polystyrene and polyethylene, and polypropylene, polyvinyl alcohol and cellulose acetate, polyvinyl chloride and polymethyl methacrylate, polyvinylidene chloride and polyarylate, and the like. Examples thereof include a uniaxially or biaxially stretched film of a transparent plastic made of polyamide or the like, an alignment film such as a liquid crystal polymer, and a transparent base material provided with an alignment layer such as a liquid crystal polymer.

The above-mentioned retardation plate may be arranged for an appropriate purpose, for example, to prevent coloring or the like due to a change in the viewing angle based on the phase difference of the liquid crystal cell, or to enlarge the good viewing angle. Therefore, the retardation plate may be formed as a superimposed body of two or more stretched films or the like.

On the other hand, the adhesive layer provided on the surface of the optical material or on one side of the protective film as an adhesive sheet is made of, for example, an appropriate adhesive such as acrylic, silicone, polyester, polyurethane, polyether, or rubber. It may be formed. Adhesion of a polarizing plate, a transparent protective layer, a retardation plate, and the like forming an optical material is excellent in stress relaxation from the viewpoint of maintaining optical characteristics, and particularly, the relaxation elastic modulus is 2 × 10 ⁵ to It is preferable that the coating is performed with an adhesive layer of 1 × 10 ⁷ dyne / cm ^{2 or} the like.

When the optical component of the present invention having the protective film bonded thereto has a polarizing plate, the display mark can be visually recognized by viewing the protective film through the polarizing plate. When the optical material does not have a polarizing plate, the display mark can be visually recognized by looking at the protective film through a separately prepared polarizing plate. Since the difference in the phase difference cannot be perceived by the naked eye, the protective film maintains the transparent function, so that the display mark cannot be known.

[0030]

【Example】

Example 1 A polyethylene terephthalate film having a thickness of 200 μm was vertically and uniaxially stretched three times at 90 ° C.
After imprinting an arrow mark through a hot stamper heated to 0 ° C., the sheet was subjected to a horizontal uniaxial stretching process at 120 ° C. to 3.5 times, and 230
The film was heat-set at a temperature of ° C. to obtain a protective film with an identification mark made of a biaxially stretched film, which was treated with a silicone-based release agent to obtain a separator.

Example 2 Methyl ethyl ketone was applied to a biaxially stretched polyethylene terephthalate film having a thickness of 200 μm through a stamper provided with an arrow mark, and then naturally dried to obtain a protective film having an identification mark. 2
An adhesive sheet was obtained by attaching a 0-μm acrylic pressure-sensitive adhesive layer.

Example 3 An iodine / polyvinyl alcohol-based polarizing plate (NPF-G1225DU, manufactured by Nitto Denko Corporation) was coated on one surface with a thickness of 20 μm.
Through the acrylic pressure-sensitive adhesive layer, a retardation plate made of a stretched polycarbonate film having a thickness of about 100 μm and a retardation plate having a retardation of 445 nm is adhered to the retardation plate side of a compensating polarizing plate, and to the separator obtained in Example 1. An acrylic pressure-sensitive adhesive layer having a thickness of 20 μm was provided and bonded, and the adhesive sheet obtained in Example 2 was bonded to the polarizing plate side to obtain an optical component.

Comparative Example 1 An arrow mark was printed with a pigment ink on a biaxially stretched polyethylene terephthalate film having a thickness of 200 μm to obtain a protective film containing an ink mark, which was treated with a silicone-based release agent to form a separator. Obtained.

Comparative Example 2 An adhesive sheet having a thickness of 20 μm was provided on one side of a protective film having an ink mark obtained according to Comparative Example 1 to obtain an adhesive sheet.

Comparative Example 3 Comparative Example 1 was used as a separator, and Comparative Example 2 was used as an adhesive sheet.
An optical component was obtained in the same manner as in Example 3 except that the above-mentioned product was used.

Evaluation Test In the optical component obtained in Example 3, the arrow mark of the separator can be visually recognized from the polarizing plate side, the arrow mark of the adhesive sheet can be visually recognized from the side of the retardation plate, and the arrow mark. Since it was on the back side of the optical material, the appearance of the optical material inside the separator or the adhesive sheet including the arrow mark part could be inspected. On the other hand, in the optical component of Comparative Example 3, the ink mark hindered the appearance inspection of the optical material in that portion.

[Brief description of the drawings]

FIG. 1 is a sectional view of an embodiment.

FIG. 2 is an explanatory diagram of display mark recognition.

[Explanation of symbols]

 1: adhesive sheet 11: protective film 12: adhesive layer 13: display mark 5: optical material (compensating polarizing plate) 2: polarizing plate 3: adhesive layer 4: retardation plate 6: adhesive layer 7: protective film (separator) 71: Display mark

Claims (3)

[Claims] 1. An optical material, comprising a pressure-sensitive adhesive layer adhered to the surface of an optical material, a retardation film separated from the optical material independently of or together with the adhesive layer, and the retardation film serves as a display mark. A protective film, wherein the display mark is formed in a region where the phase difference is partially different. 2. The protective film according to claim 1, wherein the protective film according to claim 1 is bonded via an adhesive layer to an optical material comprising a compensating polarizing plate in which a polarizing plate and a retardation plate are bonded and fixed. Optical components. 3. The phase difference plate according to claim 2, wherein the phase difference due to birefringence of the light obliquely transmitted through the phase difference plate is asymmetric on the left, right, up, or down with respect to the normal line in the main refractive index direction. Optical components that are shown.