JPS6296905A - Polarizing film laminate - Google Patents

Abstract

PURPOSE:To obtain a multi-axis polarizing film having an excellent stereoscopic projection effect by disposing two sheets of polarizing films partially having polarizing power in such a manner that the axes of polarization are perpendicular to each other. CONSTITUTION:A hydrophilic high-polymer film is uniaxially stretched 3-5 times in an aq. boric acid soln. and is dried to form a stock polarizing film 3. A base 4 is adhered by an adhesive agent to one face thereof. A photoresist 5 is coated on the film 3 and is dried. The photoresist is exposed through a photographic negative 6 and the specific pattern thereof is cured. The remaining part is dissolved away by development. The part except the cured pattern 5 is dyed to provide the polarizing power thereto and thereafter the cured pattern 5' is dissolved. The 2nd stock polarizing film 7 is laminated and adhered on the 1st film 3' in the direction orthogonal with the stretching axis thereof. The part of the film 7 corresponding to the non-colored part 3' is similarly colored to form the 2nd partial polarizing film. The partial polarizing film laminate having the axes of polarization orthogonal with each other is thus obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a polarizing film laminate. More specifically, the present invention relates to a partially polarizing film laminate in which two polarizing films having partially polarizing ability are stacked such that their polarization axes are perpendicular to each other, and a method for manufacturing the same.

Conventional technology Normally, a polarizing film is made by dyeing a film such as polyvinyl alcohol (PVA) with iodine or dye, then uniaxially stretching it uniformly in a certain direction, and then laminating and adhering cellulose triacetate (TAC) etc. on one or both sides. It is manufactured by coating with acrylic resin or the like, and is used in liquid crystal display devices and the like.

On the other hand, in order to cope with the diversification of images, polarizing films having polarization axes in multiple directions or having partial polarization ability are used for segments such as animations and toys. A polarizing film that has polarization axes in different directions is called a multiaxial polarizing film, but conventional multiaxial polarizing films are made by cutting a uniaxially stretched polarizing film into a predetermined shape (pattern). Manufactured by bonding onto a transparent support, or by applying a dichroic substance such as dichroic dye to a glass plate or transparent plastic plate and rubbing it in a specified direction with real cotton cloth or paper, etc. has been done. In addition, as a new manufacturing method, dichroic dyes are coated on a transparent substrate or contained in a transparent plastic base material, and the dyes arranged in a specific direction are selectively decomposed by irradiation with a polarized laser or beam, and the remaining dyes are converted into polarized light. A method of imparting this ability has been proposed. However, multi-axis polarizing films produced by these methods have drawbacks such as poor dimensions and precision at pattern boundaries, and poor optical properties such as polarization ratio in each region.

On the other hand, various methods have been proposed for viewing images three-dimensionally, one of which is to form polarizing film regions with mutually orthogonal polarization axes into dots or stripes corresponding to the pixels of the display. There is a method of viewing the images using glasses with the left and right polarization axes orthogonal to each other.

Problems to be Solved by the Invention In order to be able to view an image produced by a video element equipped with a multi-axis polarizing film as described above as a more three-dimensional image, it goes without saying that the polarizing film itself must have a high polarization rate. A multi-axis polarizing film is required in which the polarization axes of the two partially polarizing films are exactly perpendicular to each other. The method described above, in which a polarizing film is cut into a certain pattern, arranged so that their polarization axes are perpendicular to each other, and then bonded to another transparent film, etc., is difficult and time-consuming to bond the patterns accurately. There are drawbacks.

Means for Solving the Problems The present inventors have conducted extensive research in order to produce a multi-axis polarizing film with excellent stereoscopic imaging effects, and as a result they have arrived at the present invention. That is, the present invention has the following features: 1. A first uniaxially stretched partial polarizing film comprising a large number of colored portions having polarizing ability and uncolored portions not having polarizing ability; A partially polarizing film laminate in which a second uniaxially stretched partially polarizing film is arranged such that the colored parts correspond to the non-printed parts and the polarizing axis of the first partially polarizing film is orthogonal to the first partially polarizing film. Body 2: A uniaxially stretched colored polarizing film consisting of a large number of colored portions having polarizing ability and uncolored portions having no polarizing ability, and another uniaxially stretched uncolored polarizing element film with their stretching axes orthogonal to each other. After laminating and adhering, a resist dyeing film is provided on the part corresponding to the colored part of A, and then the part where the resisting film is not provided is colored, or a uniaxially stretched colored polarizing film is laminated on A with its polarizing axis orthogonal to each other. Manufacturing method 3 of a partially polarizing film laminate, characterized in that a protective film is provided on a portion corresponding to the non-colored portion of A by adhesion, and then the portion where no protective film is provided is bleached, colored portion having polarizing ability In the first uniaxially stretched partial polarizing film (4), which is made up of a large number of distributed uncolored parts having no polarization ability, the colored part of A has the colored part, and the uncolored part of A has the colored part. A method for producing a partially polarizing film laminate is provided, which comprises stacking second uniaxially stretched partially polarizing films that correspond to each other and whose polarizing axes are orthogonal to the polarizing axis of A.

In the present invention, the second partially polarizing film B is arranged so that the polarization axis of the first partially polarizing film B is orthogonal to that of the first partially polarizing film B.
When the laminate of A and B is seen through from above, the colored part of A and B
The colored parts are located adjacent to each other, and the polarization axes of the adjacent colored parts are orthogonal to each other.A specific example of this is the polarization axes as shown in Figure 1. A type in which the colored parts l and r of the two polarizing films are arranged alternately in a stripe pattern so that the polarizing films are perpendicular to each other, and the colored parts l and r of the two polarizing films are arranged in groups of 3 as shown in Figure 2. A type in which the polarization axes are arranged in a dot shape so that they are perpendicular to each other, or a colored part 1 as shown in Figure 3.
Examples include a type in which the polarization axes are arranged in a dot matrix pattern so that the polarization axes are perpendicular to each other in the front and rear, left and right directions. The shapes of these patterns are not particularly limited (they may be striped, triangular, square, circular, elliptical, or any other shape).The size and density of these colored portions (patterns) are determined by the image element. The width, diameter, side size, etc. of several tens of micrometers to several tens of micrometers is determined depending on the shape.If the pattern is circular or elliptical, the colored part of the first partial polarizing film 4 and the 82 part Polarizing film (B)
An uncolored area occurs at the boundary between the colored areas, but as long as the area of such an uncolored area is sufficiently small compared to the total colored area, there is no problem in viewing the stereoscopic image.

Furthermore, it is desirable that the polarization axis of the first partial polarizing film and the polarization axis of the second partial polarizing film form an angle of exactly 90 degrees, but even if the polarization axis of the first partial polarizing film and the second partial polarizing film is changed by about 10 degrees depending on the circumstances of the mounting process, etc., the present invention still applies. This does not mean that the performance of the polarizing film laminate is impaired at all.

The present invention will be explained in detail with reference to the drawings.

As shown in Figure 4, first, a hydrophilic polymer film such as a polyvinyl alcohol film, a partially acetalized polyvinyl alcohol film, or a saponified ethylene-vinyl acetate copolymer film is diluted 3 to 5 times in a boric acid aqueous solution. Uniaxially stretched and dried, a polarizing element film with a thickness of 3 to 50μ (3
), and on one side thereof, a support (4) such as a cellulose acetate film such as cellulose triacetate, a plastic film such as an axially oriented polyester film, a polycarbonate film, a polyethersulfone film, a polysulfone film, or a glass substrate, etc., and a polyurethane film. Adhesion or temporary adhesion with adhesive, epoxy adhesive, polyvinyl acetate adhesive, or polyvinyl alcohol adhesive. Next, partial polarizing ability is imparted to this single-sided polarizing element film in the following manner.

That is, for example, as shown in FIG. 5, a photoresist (photosensitive resin) (A) is coated on a polarizing element film (3), dried, and exposed to a high-pressure mercury rung, carbon arc, etc. through a photographic original plate (6).
The photoresist is exposed to light using a xenon lamp or the like to harden a specific pattern, and the remaining portion is dissolved and removed by development. If the photoresist is a so-called negative photoresist such as a dichromate photoresist, an acrylic photoresist, a polyvinyl cinnamate photoresist, or a cyclized rubber-azide photoresist, the transparency of the photographic original plate is Only the portion of the photoresist (Aa) corresponding to the portion (6a) is cured, and the unexposed portion (Ab) is dissolved and removed by development, exposing the polarizing element film surface (3b). In addition, when the photoresist is a so-called positive type photoresist such as an 0-naphthoquinone diazide photoresist, on the contrary, the photoresist area (Aa) corresponding to the transparent area (6a) of the photographic original plate (6) is exposed to light when irradiated with light. It changes to water-soluble carboxylic acid, etc., and is dissolved and removed by development, exposing the polarizing element film (3a), while the unexposed area (Ab) remains on the polarizing element film (3b) as a hardened pattern (resistance coating). . The polarizing film having a specific hardened pattern formed in this way is immersed in a solution containing iodine-potassium iodide or dichroic dye, etc., and the hardened pattern (portions other than A1 is dyed) to improve the polarizing ability. (FIG. 6) and dissolves the post-cured pattern (A) to obtain a partially polarizing film supported on one side (first partially polarizing film, 3).

(Fig. 7) Next, as shown in Fig. 8, a second polarizing element film (7) is laminated on the first partial polarizing film (3) in a direction perpendicular to its stretching axis using the same adhesive as above. Glue.

If the layer itself formed by the adhesive has insufficient water resistance and anti-staining properties, apply tannic acid or the like between the first partial polarizing film (3) and the second polarizing element film (7). Additionally, a water-resistant film or a dye-resistant film may be provided. Next, on the second polarizing element film (7), the portion corresponding to the uncolored portion of the first partial polarizing film (3) is colored with iodine-potassium iodide, dichroic dye, etc. in the same manner as described above. A second partially polarizing film is formed to obtain a partially polarizing film stack having mutually orthogonal polarization axes as shown in FIG.

Another method of partially imparting polarizing ability to a polarizing element film supported on one side is to use an ink vehicle or a resist coating formed from a printing ink. That is, first, a polarizing element film as shown in FIG. 4 is coated with an ink vehicle or printing ink by silk screen printing, offset printing, gravure printing, letterpress printing, etc., particularly preferably by silk screen printing or offset printing. A specific pattern (resist coating) is provided.

Vehicles for ink or printing/inks include, for example, synthetic resins such as cellulose plastics and polyvinyl acetate, as well as solid components such as plasticizers and desiccants dissolved or dispersed in organic solvents, or dyes, pigments, etc. Those colored in a desired hue are used. Next, parts other than the printed pattern are dyed with iodine or a dichroic dye, etc. to impart polarizing ability partially, and then, if necessary, the resist coating is dissolved and peeled off with a solvent to obtain a first partially polarizing film. . (Figure 7) Furthermore, a second partially polarizing film is placed in a direction perpendicular to the first partially polarizing film and its stretching axis.
The polarizing element films were laminated and bonded (Fig. 8), and polarizing ability was imparted to the portion corresponding to the non-colored part of the first partial polarizing film on the second polarizing element film by the same method as described above (Fig. 9). ) Obtain a partially polarizing film stack having mutually orthogonal polarization axes.

Furthermore, as a method of imparting partial polarizing ability to a polarizing element film, a printing paste is prepared by adding a paste such as sodium alginate or starch to a dichroic dye aqueous solution or an iodine-potassium iodide solution, and using this, polarized light is supported on one side. A partially polarizing film can also be obtained by printing a specific pattern on the base film and then subjecting it to moist heat treatment.

In the above polarizing film laminate, the portions of each polarizing film that have polarization ability are of a single color, but as shown in FIG.
A partially polarizing film laminate colored in the three primary colors of (red), G (green), and B (blue) can also be manufactured by the same method as described above.

That is, a resist coating is formed using a photocurable resin, an ink vehicle, a printing ink, etc. on a first polarizing element film supported on one side by a plastic film or glass substrate, and is first exposed with a red dichroic dye. The dyed area is dyed, and then the resist coating is removed. Next, a resist coating is applied to the red dyed portion using a photocurable resin, an ink vehicle, a printing ink, etc., and the resist coating is peeled off after dyeing with a green dichroic dye.

Finally, a resist coating is applied in the same manner as above, including the areas already dyed with red and green, and after dyeing with a blue dichroic dye, the resist coating is peeled off to give R,...
, B Obtain the first partially polarizing film (3) (Fig. 10), half of which is dyed with the three primary colors. Next, the first partially polarizing film (3
A second polarizing element film is laminated and adhered on 1' in a direction perpendicular to the stretching axis, and the above-described film is applied to the area of the second polarizing element film corresponding to the undyed part of the first partial polarizing film (3'). It is also possible to form a polarizing film (7) of three primary colors of RG and H using a similar method to obtain a partially polarized polarizing film in which the polarization axes of the colored portions are orthogonal to each other.

All of the above methods for forming partially polarized films use photocurable resin,
This is a method of dyeing the parts other than the resist coating formed with an ink vehicle or printing ink, etc., but the above is applied to an axially stretched polarizing film whose entire surface is uniformly colored (or dyed) with iodine or dichroic dye, etc. Similarly, a partially polarizing film can be obtained by providing a protective film using a photocurable resin, an ink vehicle, or a printing ink, and decolorizing the other parts to eliminate the polarizing ability. That is, according to the usual polarizing film manufacturing method, first, for example, a polyvinyl alcohol film is dyed with iodine or a dichroic dye, and 3 to 5
After stretching the film to double its original size, one side of the film is laminated with TAC or coated with acrylic resin to obtain a polarizing film. A protective film is provided on this using a photocurable resin, an ink vehicle, or a printing ink, and the portion other than the protective film is decolored to eliminate the polarizing ability. (For decolorization, if the polarizing film is colored with iodine, use a 0.1 to 10% caustic potash or caustic soda solution at 10 to 60°C; if the dye is colored with iodine, e.g. The area is decolorized by treatment with ~10% hypo or hydrosulfide aqueous solution at 15-60°C.) After decolorization, wash with water and, if necessary, remove the protective film of photocurable resin, ink vehicle, printing ink, etc. Partially polarizing film (first polarizing film)
Partially polarizing film) is obtained. Next, a second polarizing film is laminated and bonded so that the polarizing axis of the first partially polarizing film and the polarizing axis thereof are perpendicular to each other, and a portion corresponding to the colored portion of the first partially polarizing film is placed on the second polarizing film. Decolorization is performed in the same manner as described above to obtain a partially polarizing film laminate.

In addition, when manufacturing a partially polarizing film laminate with a rough pattern, such as a pattern size of several hundred μ to several mm, a single-sided supported film having a pattern corresponding to the first polarizing film and a pattern corresponding to the second polarizing film is used. For example, the partially polarizing film is prepared in advance by the method described below, and then the first polarizing film and the second polarizing film are made so that their colored parts and heat-bonded parts correspond accurately, and the two parts are separated. This can also be achieved by laminating and bonding the polarizing films so that their polarization axes are perpendicular to each other. In this case, an efficient method for producing a partially polarizing film supported on one side is, for example,
A hydrophilic polymer film such as polyvinyl alcohol is continuously uniaxially stretched 3 to 4 times in a boric acid aqueous solution, dried, and then printed using a color dye or an iodine-potassium iodide solution and a sizing agent such as sodium alginate. A method of forming a printing pattern with glue, pre-drying, and then applying wet heat treatment, or applying an iodine-potassium iodide solution or dichroic dye in a monochrome or multicolor pattern on the polarizing element film of the laminate using an inkjet method. However, after pre-drying, a method of wet heat treatment is adopted.

In the present invention, the surface of the second partially polarizing film of the partially polarizing film laminate produced as described above can be further protected with a coating or a transparent support, or conversely, the surface of the second partially polarizing film of the partially polarizing film laminate produced as described above can be further protected with a coating or a transparent support.
The plastic film or glass substrate supporting the polarizing film can also be peeled off and used.

Example Next, the present invention will be explained in more detail with reference to Examples.

Example 1 Polyvinyl alcohol film uniaxially stretched 4 times (
Polarizing element film, thickness 28μ) with Takenate A-40 and Takelac A385 (polyurethane adhesive, Takeda Pharmaceutical Co., Ltd.)
Therefore, it was laminated and adhered to a cellulose triacetate film of 80 μm to form a polarizing element film laminate supported on one side. On this polarizing element film, BPPR and a photosensitive liquid (negative photocurable resin, manufactured by Tokyo Ohkareki Co., Ltd.) were uniformly coated using a spin coater and dried to form a 6 μm film. A striped photographic original plate with alternating 350μ wide transparent areas and 350μ wide black light-shielding areas was closely attached to this film and irradiated with a 2Y ultra-high pressure mercury lamp at a distance of 100an for 30 seconds to harden the exposed areas, followed by EPPR development. Immerse it in a liquid to dissolve and remove the resin in the unexposed areas. Next, the laminate was coated with Direct Fast Bl.
2 g of ackD was immersed in a dye solution (30°C) dissolved in 11 parts of water for 3 minutes, washed with water, and dried.

Next, this laminate was immersed in an EPPR stripping solution for 4 minutes and washed with water to obtain a first polarizing film having partial polarizing ability. A second polarizing element film similar to the above was laminated and bonded to the non-laminated surface of the cellulose IJ acetate film of this polarizing film with the stretching axis perpendicular to the above-mentioned polyurethane adhesive. Furthermore, in the same manner as above, a photocurable resin is uniformly applied and dried, and the photocurable resin coated surface of the photographic thick plate is adjusted so that the exposed area of the photographic original plate corresponds to the colored area of the first polarizing film. It was exposed to light using an ultra-high pressure mercury lamp, and the unexposed areas were dissolved and removed using a developer to obtain a cured resin resist film. Next, the exposed part of the polarizing element film was exposed to Direc.
It was dyed with a dye solution of tFast Black D, and then the resist coating was peeled off with a release agent to obtain a polarizing film laminate whose polarization axes were at right angles to each other and partially imparted with polarizing ability.

Example 2 Polyvinyl alcohol film uniaxially stretched 4 times (
A cellulose triacetate film (support, 80 μm thick) was laminated and adhered to one side of the 28 μm thick film using the polyurethane adhesive described above.

This laminated film (IQcmX15Cm) was immersed (at 40°C) in a dye bath consisting of 1 part of iodine, 5 parts of potassium iodide, 5 parts of boric acid, and 100 parts of water, washed with water, and dried to form a single-sided polarizing film. Obtained. After forming a protective film by printing a stripe pattern with a width of 350μ at 350μ intervals using colored mejum ink on the non-supporting side of the polarizing film using the silk screen printing method, a 2°5% hydrosulfite solution was applied. The area without the protective film was immersed in water to bleach the color and eliminate the polarizing ability. Thereafter, the protective film was peeled off using a solvent to obtain a 10th partially polarizing film. Furthermore, the first
The stretched polyvinyl alcohol film was adhered with a polyurethane adhesive so that the polarizing film and its stretching axis were perpendicular to each other, and the entire surface of the film was uniformly dyed with iodine, potassium iodide, and boric acid in the same manner as above. Next, in step 5, the first partially polarizing film was treated in the same manner as described above to decolorize the portion corresponding to the dyed portion, to obtain a polarizing film laminate having a partially polarizing ability whose polarization axes were perpendicular to each other.

Effects of the Invention A polarizing film laminate in which two polarizing films partially having polarizing ability, the portions having polarizing ability and the portion not having polarizing ability of each film accurately correspond to each other, and the polarizing axes of each film forming an exact right angle can be obtained. Ta.

This material is used as a multi-axis polarizing film as a medium for viewing images three-dimensionally.

[Brief explanation of drawings]

FIG. 1 shows an example of a polarizing film laminate in which orthogonal polarization axes are arranged in stripes. FIG. 2 shows an example of a polarizing film laminate in which orthogonal polarization axes are arranged in a group dot shape. FIG. 3 shows an example of a polarizing film laminate in which orthogonal polarization axes are arranged in a dot matrix. FIG. 4 shows a polarizing element film supported on one side. FIG. 5 shows a pattern forming method using a photoresist method. FIG. 6 shows a state in which a turn is formed using a photocurable resin or printing ink and then colored. FIG. 7 shows a first polarizing film that partially has polarizing ability. FIG. 8: A second polarizing element film is laminated and bonded onto a first polarizing film that partially has polarizing ability so that its stretching axes are perpendicular to each other. Fig. 9 Polarizing film laminate Fig. 10 Polarizing film laminate in which the polarizing film is colored in multiple colors In Figs.
polarization axis).

Claims (3)

[Claims] (1) A first uniaxially stretched partial polarizing film comprising a large number of colored portions having polarizing ability and uncolored portions having no polarizing ability; A partially polarizing film laminate in which a second uniaxially stretched partially polarizing film is arranged such that each colored part corresponds to the colored part and the polarizing axis of the first partially polarizing film is perpendicular to the first partially polarizing film. (2) A uniaxially stretched partially polarizing film (
A) is laminated and bonded with another uniaxially stretched uncolored polarizing element film with their stretching axes perpendicular to each other, and then a resist dyeing film is provided on the portion corresponding to the colored portion of A, and then a portion where the resist dyeing film is not provided. or by laminating and adhering a uniaxially stretched colored polarizing film to A with the polarization axes orthogonal to each other, then providing a protective film on the part corresponding to the non-colored part of A, and then decoloring the part where the protective film is not provided. A method for producing a partially polarizing film laminate characterized by (3) In the first uniaxially stretched partial polarizing film (A), which is made up of a large number of colored parts having polarizing ability and non-colored parts not having polarizing ability, the colored part of A also has the colored part of A. A partially polarizing film laminate, characterized in that a second uniaxially stretched partial polarizing film is laminated whose colored parts correspond to the uncolored parts and whose polarization axis is orthogonal to the polarization axis of A. Manufacturing method