JP4073695B2 - Optical filter for display screen - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical filter for a display screen, which is attached to the front of a display screen of a liquid crystal display and controls the field of view by the lens effect of a lens film. This prevents the image from being seen from the direction and prevents peeping from the side. Furthermore, in addition to preventing peeping from the side, the pattern made up of characters and figures hidden in the optical filter is not visible from the front, but is visible from the oblique direction with respect to the front. Eye-catching properties are added.
[0002]
[Prior art]
Electronic display devices such as liquid crystal displays are not limited to the field of OA equipment such as personal computers, word processors, copiers, facsimiles, etc., but include a wide range of cash dispensers, ATMs, game machines, televisions, watches, telephones, factory control devices, etc. Used in. In particular, cash dispensers, ATMs, notebook personal computers, mobile phones, mobile phones, and the like are required to have a visibility control function for preventing peeping from the electronic display device in order to protect privacy.
[0003]
As a means for imparting the above-described visibility control function, the inventor of this application uses a lens film formed with fine irregularities on one side of a film made of a polymer material as a constituent material, and attaches it to the front of the display screen of the display. An optical filter for a display screen that controls the visible range has been proposed (see Japanese Patent Application No. 2001-153288). However, this invention of the prior application is not used when the wallpaper on the desktop screen of a Windows PC is a plain blue color, but when the screen is white and bright, for example, on the initial screen of the PC software "Excel". However, under the circumstances where the visibility control performance is not sufficient and the brightness of the screen is improved with the recent progress of the liquid crystal panel, the improvement is necessary.
[0004]
Moreover, in addition to the above-mentioned visibility controllability, design requirements and eye-catching properties are provided, and market requirements for a function that allows images and characters that are not visible from the front to be seen from an oblique direction with respect to the front. Occurred. As a means for imparting this function, the use of a transparent hologram is known (see Japanese Patent Application Laid-Open No. 11-133233). However, this method does not have a sufficient visibility control function, and the image is viewed when viewed from the front. There is a problem that the property is inferior, expensive and inferior in economy.
[0005]
[Problems to be solved by the invention]
This invention solves the above-mentioned problems of the prior art and provides an optical filter for a display screen that has sufficient visibility control even on a bright screen such as the initial screen of the PC software "Excel" and has excellent peeping prevention properties. To do. In addition to the above-described visibility control function, the present invention adds a function of making an image, a character, or the like invisible from a substantially front view visible from an oblique direction with respect to the substantially front view. It improves catchability.
[0006]
[Means for Solving the Problems]
  The optical filter for a display screen according to the present invention comprises a lens film formed with fine irregularities on one side of a film made of a polymer material, and is attached to the front of the display screen of the display for controlling the visible range. In an optical filter for display screen, for attaching the optical filter to the front surface of the display screen directly on the plane side of the lens film or via a base film made of a transparent thermoplastic polymer material laminated on the plane side. Adhesive is applied and used for the above laminationTransparentFor mounting on the adhesive or adhesive layer and above display screenTransparentAn air layer is provided on at least one of the adhesive layers.The air layer is patterned into the shape of characters or figures, and the pattern shape forms a latent image that cannot be seen from the front of the optical filter for display screen.It is characterized by.
[0007]
The above-described lens film may have any surface structure or material as long as it can exhibit a lens function depending on its surface structure. As a surface structure, a honeycomb structure formed by arranging a plurality of convex and concave portions of a pyramid shape, a convex lens shape or a Fresnel lens shape vertically and horizontally on one side of a synthetic resin film (including a sheet), and a cross-sectional shape is triangular, trapezoidal, Examples include a ridge structure in which a large number of straight ridges such as a rectangle or a semicircle are arranged in parallel. In this case, the lens portions such as the convex portions, the concave portions, and the straight ridges may be arranged adjacent to each other or arranged with a slight gap therebetween. And said lens film may be a single structure consisting of any one of the above-mentioned convex part, concave part or linear protrusion, or may be a combination structure of two or more kinds.
[0008]
The above lens film is made of a transparent synthetic resin film as a raw material, and is subjected to hot pressing with a female mold having a lens structure or an embossing roll, or the surface pattern of a releasable sheet having a lens structure is a synthetic resin. A single layer structure can be produced by transferring to a film. In addition, when the lens film is attached to the front surface of the display screen, it is preferable that the lens surface of the lens film is directed not to the display screen side but to the front side opposite to the display screen. In consideration of the contact of the hand and touch pen, a film made of the above-mentioned transparent thermoplastic polymer material is used as a support film, and a lens film is formed on the surface with a material having excellent scratch resistance and antifouling properties. Thus, a composite lens film having a two-layer structure can be obtained.
[0009]
When forming a single layer structure lens film by molding a convex part, concave part, straight ridge etc. on one side of the synthetic resin film by hot pressing or transfer method, the material can be used by forming the lens surface, Any transparent thermoplastic polymer material may be used, but preferred are polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate and their modified products, polycarbonate, polymethyl methacrylate, polymethyl acrylate, etc. Methacrylic acid esters and acrylic acid ester homopolymers or copolymers, polystyrene, polymethylpentene, cyclic polyolefin polymers and their modified products, triacetyl cellulose, polyvinyl chloride, polyvinylidene chloride, and the like.
[0010]
On the other hand, in the case of producing a composite lens film, a lens structure made of a transparent curable resin is formed on a support film made of a transparent synthetic resin with a gravure roll, and then this lens structure portion is cured by a crosslinking treatment to be resistant to damage. Scratch property can be obtained. The curing method in this case is arbitrary, and may be performed by heating, or by irradiation with active rays such as ultraviolet rays, electron beams, and radiation. Furthermore, a flat surface of spherical or hemispherical transparent or translucent fine particles can be adhered to one side of the support film with an adhesive.
[0011]
Examples of such a scratch-resistant material include a single or a mixture of two or more curable resins such as melamine, urethane, acrylic, silicone, and oxetane. Moreover, hybrid curable materials of these curable resins and inorganic compounds can also be used. When using this curable material,supportA method of laminating the above-mentioned curable material on a film, forming a lens structure in an uncured or semi-cured state, and then performing a curing treatment again to end the curing is preferable. The curing method is not particularly limited, but a method of curing with active rays such as ultraviolet rays and electron beams is preferable in terms of easy control of the curing degree.
[0012]
The spherical or hemispherical fine particles are not particularly limited as long as they are transparent or translucent, and may be any of inorganic materials, organic materials, or hybrids of both, and silica or glass as inorganic materials, Examples of the organic material include acrylic, polyester, and olefin polymers, and examples of the hybrid include a composite of silica and a polymer.
[0013]
The fine particles preferably have a high light refractive index. For example, in the case of glass, a metal such as lead is added, and in the case of silica, titanium oxide is preferably added. In the case of a hybrid body, it is preferable to use glass added with a metal such as lead or silica added with titanium oxide. And the adhesive agent should just be transparent or semi-transparent resin, and the said curable resin is illustrated.
[0014]
In the lens part such as the convex part, concave part or linear protrusion, the width and height can be arbitrarily set, but the preferred width and height are 10 to 1000 μm, particularly 10 to 500 μm. preferable. In order to avoid moiré, it is preferably 200 μm or less. Moreover, when forming a convex part with microparticles | fine-particles, the magnitude | size is preferable 10-1000 micrometers, Especially 10-500 micrometers is preferable and in order to avoid a moire, 200 micrometers or less are preferable.
[0015]
When the optical filter of the present invention is attached to the front surface of the display screen by an arbitrary attachment means, the light transmittance in the normal direction relative to the display screen is maximized, and the image on the display screen can be clearly seen from the front. However, when the angle at which the image is viewed is shifted from the front to the side, the visibility of the image gradually decreases due to the lens effect of the lens film, and when the angle exceeds a certain angle, the content of the image becomes unclear. That is, peeping from the side can be prevented. In addition, when a lens film is formed with a linear protrusion, it can be attached so that a linear protrusion may incline 20 to 45 degree | times with respect to the horizontal side of a screen, and the visibility from a front can be improved. However, if the tilt angle is less than 20 degrees, the visibility control function is insufficient, and if it exceeds 45 degrees, moire occurs.
[0016]
And the optical filter of this invention is theNon-lens surface side of lens film, that is, plane sideSince the air layer is interposed between the lens film and the lens film, the lens effect of the lens film is enhanced and the visibility controllability is improved. The portion where the air layer is provided is arbitrary as long as it is between the display screen on which the optical filter is mounted and the lens film portion of the optical filter. For example, a lens film part may be sufficient and the support film of a lens film may be sufficient. Further, the optical filter may be attached to the display screen. The layer for providing the air layer may be one layer or two or more layers. The thickness of the air layer is preferably 0.1 to 100 μm. If the thickness is less than 0.1 μm, the effect of the air layer is not recognized. On the other hand, if the thickness exceeds 100 μm, the visibility from the front is lowered.
[0017]
Air layer aboveThe lightAdhesive used to mount the filter to the screenMedicinalPattern the coating shape, and the uncoated part is the air layerPreferably. Moreover, the thickness of the coating thickness can be patterned and the thin portion can be used as an air layer.Also, Lens filmLaminate a base film onAndUsed for this laminationAn air layer may be formed on the pressure-sensitive adhesive layer or the adhesive layer..
[0018]
The air layer portion looks whitish from an oblique direction with respect to the front surface, and the surface reflectivity of the portion becomes high, and exhibits a color tone different from that of the portion without the air layer. Further, the air layer forms a latent image whose presence cannot be visually recognized from substantially the front, and only the image on the display screen is clearly visible. Therefore, when the air layer is patterned, the air layer pattern emerges when viewed obliquely. That is, if the air layer pattern is a character or an image, such latent information can be viewed from an oblique direction, and the design and eye catching properties of the optical filter can be enhanced. The air layer patterning means is not limited and is arbitrary. Among the examples of the method for providing the air layer, a method of patterning a pressure-sensitive adhesive or an adhesive is suitable, but the method is not limited to this.
[0019]
The optical filter of the present invention is preferably used by directly attaching to the display screen of the display. In particular, it is preferable to be detachable. In this case, it can be attached as necessary to exhibit the visual field control function, and can be removed when not needed. Although the attachment means is arbitrary, it is preferable to form the back side of the optical filter in a flat surface, and this flat surface should be in direct contact with the display screen, thereby suppressing the generation of multiple images other than the display image and improving the visibility. To do.
[0020]
As the attachment means, it is preferable to use a self-adhesive layer having a smooth surface made of a flexible polymer and having self-adhesiveness and removability. That is, a self-adhesive layer made of a transparent flexible polymer is laminated on the non-lens surface of the lens film directly or through a base film, and is pasted on the front surface of the display screen with the self-adhesive force of the self-adhesive layer. Well, in this case, by cutting to the desired size, placing it on the target display screen, and pressing it with your hand, you can evenly install it without putting bubbles between the self-adhesive layer and the display screen. It can be used after being peeled off and pasted again if necessary, and can be reattached even if there is a sticking error. This is preferable in that the display screen is not soiled.
[0021]
The above-mentioned flexible polymer is made of rubber, soft vinyl chloride, elastomer or plastomer. As rubber, natural rubber, silicone rubber, ethylene propylene rubber, acrylonitrile butadiene rubber, styrene butadiene rubber, chloroprene rubber, acrylic rubber, fluoro rubber And urethane rubber, etc., as soft vinyl chloride, vinyl chloride resin blended with plasticizers and other soft polymers, as elastomer, polyester-based, polyamide-based and polyolefin-based thermoplastic elastomers, and as plastomer Are exemplified by polyolefin plastomers. In addition, these flexible polymers may be used alone or in combination of two or more.
[0022]
The flexible polymer can contain various functionalizing agents and stabilizers as long as the transparency is not impaired. And since the optical filter of this invention is affixed on the front surface of a display screen using the self-adhesive force of the self-adhesive layer made of the above-mentioned flexible polymer, it is unnecessary to add an adhesion assistant. The adhesive strength can be increased by blending an adhesion aid within a range that does not impair the object of the present invention.
[0023]
The self-adhesive force is generated by smoothly forming the surface of the adhesive layer made of a flexible polymer. In this case, a preferable average surface roughness (Ra) is 0.12 μm or less. Particularly preferred is 0.08 μm or less, and most preferred is 0.05 μm or less. When the average surface roughness (Ra) exceeds 0.12 μm, no self-adhesive force is generated, and it becomes impossible to fix the optical filter of the present invention with the self-adhesive force of the self-adhesive layer.
[0024]
The surface layer has a dynamic hardness of 0.01 to 20 mN / 25 μm.² Is preferred. Especially 0.02-10mN / 25μm² Is preferable, 0.04 to 5 mN / 25 μm² Is most preferred. This dynamic hardness is 0.01 mN / 25 μm.² If it is less than 1, the peeling becomes difficult and the repairability including the re-attachment is lowered, and on the contrary, 20 mN / 25 μm.² If it exceeds, the fixing force will be insufficient.
[0025]
The initial adhesive force on the surface of the self-adhesive layer can be controlled by the type of flexible polymer constituting the self-adhesive layer, the type and amount of pressure-sensitive adhesive added to this, A preferable size of the initial adhesive strength is 29 to 1960 mN / 25 mm. When the initial adhesive strength is less than 29 mN / 25 mm, the optical filter tends to drop off from the display screen. On the other hand, when the initial adhesive strength exceeds 1960 mN / 25 mm, the repairability is lowered.
[0026]
The self-adhesive layer made of the above flexible polymer is formed on the flat side of the optical filter, that is, on the flat side in the case of a lens film having no support film, and on the surface of the support film in the case of a lens film with a support film. Can be formed by any method such as laminating by extrusion method or coating method. And this self-adhesion layer may be formed on the whole plane side of an optical filter, and may be formed partially. A screen printing method is exemplified as this partly forming means. Further, a lens film can be made of the above flexible polymer, for example, vinyl chloride resin, and the non-lens surface can be formed into a self-adhesive layer having a smooth surface and self-adhesiveness and re-peelability. An optical filter having a single layer structure having a lens surface on one side and a self-adhesive layer on the opposite side is obtained.
[0027]
The thickness of the self-adhesive layer and the thickness of the optical filter for display screen excluding the self-adhesive layer are arbitrary and can be appropriately set according to market demands. The thickness of the optical filter excluding the self-adhesive layer is set to 1 to 300 μm and 10 to 300 μm, respectively.
[0028]
In addition, the optical filter for display screen of the present invention can protect the surface by laminating a peelable cover film on the surface of the self-adhesive layer, and the self-adhesive when the optical filter is rolled up. It is possible to improve the winding characteristics. In this case, by sticking the surface of the self-adhesive layer to the surface of the display screen while peeling the cover film, the adhesion progresses by self-adhesion, and the air filter is stuck without being caught between the optical filter and the display screen. Is done. And even if air is bitten, it is excellent in repairability as described above, so it is possible to peel off the part containing the air and re-attach it, and to suppress the air by pressing with a weak force from above the optical filter I can escape.
[0029]
On the other hand, fine irregularities can be formed on the surface of the self-adhesive layer, and an air layer can be interposed with the self-adhesive layer. Also, as the above attachment means, a suction cup type adhesive layer is formed on the opposite lens surface of the lens film to give adhesiveness and removability, and an air layer is formed on the part without the adhesive layer on the display screen. It can also be attached.
[0030]
In addition, visibility control property can be improved and fashionability can be improved by mix | blending dye and a pigment with at least one of the lens film which comprises said optical filter, a support film, a base film, and a self-adhesion layer. The dye or pigment to be used is not particularly limited, but phthalocyanine-based ones are preferable from the viewpoint of improving visibility control and weather resistance. Moreover, the designability and visibility controllability can be improved by providing a printing layer on the anti-lens surface of the lens film or the substrate film.
[0031]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1
A hard coat agent made of an ultraviolet curable resin is laminated on a support film made of a transparent synthetic resin to a thickness of 5 to 35 μm to a thickness of 10 to 300 μm, and the obtained hard coat layer is semi-cured by ultraviolet irradiation. A large number of linear protrusions are formed in the longitudinal direction on the coating layer, followed by irradiation with ultraviolet rays again to complete the curing of the hard coating layer to obtain a composite lens film. FIG. 1 shows the above-described composite lens film 10, 11 is a support film, 12 is a lens film, and the linear protrusion 12 a of the lens film 12 is formed in a trapezoidal cross section. The arrangement pitch of the linear protrusions 12a is set to 30 to 300 μm, and the height is set to 10 to 300 μm.
[0032]
In FIG. 1, 20 is a self-adhesive composite film, a self-adhesive layer 22 having a thickness of 3 to 200 μm made of a flexible polymer and a thickness 3 to 3 on the lower surface of a base film 21 having a thickness of 3 to 350 μm made of a transparent synthetic resin. A 200 μm easily peelable cover film 23 is laminated in order, the obtained laminate is introduced into an electron beam irradiation device, and a self-adhesive layer 22 made of silicone rubber is crosslinked. The lower surface of the self-adhesive layer 22 is formed as a smooth surface having an average surface roughness (Ra) of 0.12 .mu.m or less by transferring the surface shape of the cover film 23 by laminating the cover film 23.
[0033]
A large number of dots or honeycomb-like, lattice-like or other net patterns are printed on the entire upper surface of the base film 21 of the self-adhesive composite film 20 using a dry laminating adhesive, and the thickness is 0.3 to 100 μm. The adhesive layer 24 is formed. And the support film 11 of the said composite lens film 10 is piled up and bonded together to this adhesive bond layer 24, The 5 layer structure which consists of the lens film 12, the support film 11, the adhesive bond layer 24, the base film 21, and the self-adhesion layer 22 Get an optical filter. In this optical filter, the void portion 24a where the adhesive is not applied in the adhesive layer 24 forms an air layer.
[0034]
The optical filter is used for visual field control by being attached to an arbitrary liquid crystal screen with the self-adhesive layer 22. In that case, due to the action of the lens film 12, the visibility when the screen is viewed from substantially the front is high, but the visibility when viewed from the side is low, and the viewing direction is shifted laterally, exceeding a certain limit. The image is completely invisible. That is, it has visibility controllability. In addition, since the air layer 24a is provided, the visibility of the image when viewed from substantially the front is improved and the visibility when viewed from the side is reduced as compared with the case where there is no air layer. That is, the visibility control function is improved.
[0035]
In addition, since the optical filter includes the self-adhesive self-adhesive layer 22 made of a flexible polymer on the back surface, the optical filter can be attached to the display screen without using an adhesive or an adhesive. Since the cover film 23 is provided on the surface of the self-adhesive layer 22, only the self-adhesive layer 22 is brought into contact with the display screen or the like while peeling the cover film 23, and the self-adhesion proceeds by the weight of the optical filter. In addition, air intervening between the optical filter and the display screen is pushed out by self-adhesive force, so that air can be easily prevented from being caught. When the above optical filter is cut into the shape of the liquid crystal screen to be attached, the linear protrusion 12a of the lens surface is inclined at an angle of 20 to 45 degrees with respect to the horizontal side of the liquid crystal screen ( (See FIG. 2) It can be cut and used. In this case, the visibility is improved as compared with the case where the linear protrusion 12a is directed in the vertical direction or the horizontal direction.
[0036]
The cross-sectional shape of the linear protrusion 12a of the lens film 12 can be appropriately changed. For example, the straight ridge 12b shown in FIG. 3 has a cross-sectional shape of a kamaboko shape. Moreover, the straight protrusion 12c shown in FIG. 4 has a square cross-sectional shape. Furthermore, the cross-sectional shape can be formed in a semicircle, an anti-elliptical shape, a triangle, or the like. Moreover, it can replace with the linear protrusion 12a, 12b, 12c, etc., and as shown in FIG. 5, many convex parts 12d can also be provided densely. In the example of FIG. 5, lens-shaped convex portions 12d made of spherical surfaces are densely arranged along a straight line to form a lens row, and one convex portion 12d of adjacent lens rows is arranged with respect to the other convex portion 12d. Are arranged in a staggered manner.
[0037]
Embodiment 2
In Embodiment 1 described above, the adhesive layer 24 on the base film 21 is formed to have a uniform thickness on the entire surface to eliminate the air layer 24a, while the cover film 23 of the self-adhesive layer 22 has surface irregularities. Using this, irregularities are formed on the surface of the self-adhesive layer 22. Then, the cover film is peeled off and the self-adhesive layer 22 is attached to the display screen, whereby an air layer is formed between the self-adhesive layer 22 and the display screen by a concave portion on the surface of the self-adhesive layer 22.
[0038]
Embodiment 3
In the first embodiment, the self-adhesive composite film 20 is omitted, and as shown in FIG. 6, an ultraviolet curable adhesive is formed on the lower surface of the support film 11 of the composite lens film 10 in the form of dots, honeycombs, lattices, or the like. The pressure-sensitive adhesive layer 25 is formed by printing in the pattern, and the composite lens film 10 is pasted on the display screen with the pressure-sensitive adhesive layer 25. By this pasting, the gap in the pressure-sensitive adhesive layer 25 where the pressure-sensitive adhesive is not applied is formed. An air layer is formed at the portion 25a.
[0039]
Embodiment 4
In the third embodiment, when the ultraviolet curable adhesive is printed in the form of dots on the lower surface of the support film 11 of the composite lens film 10, as shown in FIG. 7, the top of the dot-shaped convex portion 26 made of the adhesive is used. A recess 26a is formed in the bottom. That is, a sucker-shaped dot-shaped convex portion 26 is formed, and the composite lens film 10, that is, the optical filter is pasted on the display screen by the sucker-shaped dot-shaped convex portion 26.
[0040]
Embodiment 5
In the self-adhesive composite film 20 of the first embodiment, the adhesive layer 24 is formed by printing a large number of dots 24b (see FIG. 8) on the entire upper surface of the base film 21 using an adhesive for dry lamination. At this time, the distribution density of the dots 24b is unevenly distributed, and a specific character, figure, symbol, or the like is represented by a rough portion or a dense portion. In this case, when the obtained optical filter is affixed to the display screen, the letters and the like of the air layer are not visible from the front, but are visible from the side, so that the design and eye catching properties are improved.
[0041]
Embodiment 6
In the first to fifth embodiments, the support film 11 of the composite lens film 10, the lens film 12, the base film 21 of the self-adhesive composite film 20, and the self-adhesion layer 22 are colored with a dye or a pigment, When the light transmittance is preferably lowered to about 90 to 50%, visibility controllability is improved.
[0042]
【Example】
We prototyped various optical filters for display screens and compared their performance.
[0043]
Example 1
(1) Manufacture of compound lens film
A hard coat agent made of a commercially available acrylic ultraviolet curable resin was applied to one side of a support film 11 made of polyester having a thickness of 50 μm (see FIG. 1) so as to have a thickness of 30 μm. Semi-cured by UV irradiation. Next, using a sculpture roll, a large number of straight protrusions 12a are formed in the above-mentioned hard coat layer 12 in a trapezoidal cross section, and subsequently, the hard coat layer is cured by irradiating again with ultraviolet rays. A composite lens film 10 composed of a scratch-resistant lens film 12 having 12a and a support film 11 was obtained. The width of the top part and the trough part of the lens film 12 was 10 μm, the inclination angle of the side was 45 degrees, and the distance between the top parts was 100 μm.
[0044]
(2) Manufacture of self-adhesive composite film
Plasma treatment was performed on one side of a base film 21 made of a polyester film and having a thickness of 38 μm. Moreover, the easy-peelable process was given to the single side | surface of the polyester film of thickness 25 micrometers, and it was set as the cover film 23. FIG. On the other hand, a commercially available highly transparent silicone rubber composition (rubber hardness 10 degrees) was dissolved in toluene, and pentaerythritol tetraacrylate was added thereto as an adhesion improver for the base film 21 to obtain a coating solution. The coating liquid is applied to the plasma-treated surface of the base film 21 so that the thickness of the silicone rubber is 25 μm to form a self-adhesive layer 22, and the cover film 23 is formed on the surface of the self-adhesive layer 22. It laminated | stacked so that the easily peelable process surface might contact | connect. The obtained laminate was introduced into an electron beam irradiation apparatus, and the self-adhesive layer 22 made of silicone rubber was crosslinked.
[0045]
(3) Manufacture of optical filters
On the surface of the base film 21 of the self-adhesive composite film 20, the adhesive 24 for dry lamination is formed into a honeycomb pattern (thickness: 3 μm, line width: 100 μm, hexagonal side length: 1000 μm) using a gravure roll. The optical filter was obtained by pasting the support film 11 of the composite lens film 10 manufactured by the above method on the coated surface. In this optical filter, the air gaps 24a to which the dry laminating adhesive was not applied formed an air layer.
[0046]
When the optical filter obtained by the above method is cut into a shape corresponding to the shape of the liquid crystal screen, the linear protrusion 12a of the composite lens film 10 is inclined at an angle of 30 degrees with respect to the horizontal side of the liquid crystal screen. (See Fig. 2) Cut the optical filter to the display screen (the initial screen of "Excel" on Windows PC) with the self-adhesive strength of the self-adhesive layer 22 (see Fig. 1) while peeling the cover film 23 on the back side. Pasted. This optical filter has high image visibility when viewed from substantially the front, but has low visibility when viewed from the side, and the viewing direction exceeds approximately 50 degrees horizontally with respect to the normal direction of the display screen. The above image disappeared at all. That is, it has a peeping prevention effect by the viewing angle control function.
[0047]
In addition, since the optical filter includes the self-adhesive layer 22 made of a flexible polymer on the back surface, the optical filter can be attached to the display screen without using an adhesive or an adhesive. Since the cover film is provided on the surface, the self-adhesion layer can be brought into contact with the display screen, etc., only by peeling the cover film, and the self-adhesion proceeds with the weight of the optical filter. Air intervening between the filter and the surface of the display screen or the like was pushed out by self-adhesive force, and air could be easily prevented from being caught. In addition, the optical filter has an appropriate initial adhesive strength of the self-adhesive layer, so that it has excellent fixing strength and is easy to peel after being attached to a display screen or the like, and can be peeled off with a weak force. And there was no surface contamination on the display screen after peeling, and the repairability was excellent.
[0048]
Comparative Example 1
In Example 1 described above, when the composite lens film 10 and the self-adhesive composite film 20 are bonded together, the adhesive for dry laminating is applied to the entire surface without patterning and bonded together. An optical filter was obtained in the same manner as in Example 1 except that no air layer was formed between the adhesive composite film 20 and the adhesive composite film 20. The visibility control performance of the optical filter of Comparative Example 1 was evaluated in the same manner as in Example 1. The angle at which the image disappeared was about 75 degrees, which was 25 degrees wider than that of Example 1, and the visibility control performance was inferior to that of Example 1.
[0049]
Example 2
A hard coat agent made of a commercially available transparent type acrylic UV curable resin is printed on one side of a support film 11 (see FIG. 3) made of a polyester film with a thickness of 50 μm by a gravure roll to form a straight ridge 12b having a semi-cylindrical cross section. A large number of films were formed, and then irradiated with ultraviolet rays to obtain a composite lens film 10 composed of a scratch-resistant lens film 12 having a large number of linear protrusions 12 b and a base film 11. The thickness of the lens film 12 was 100 μm, the depth of the valley was 90 μm, the width of the linear protrusions 12b was 150 μm, and the interval between the linear protrusions 12b was 300 μm. Otherwise, the optical filter of Example 2 was obtained in the same manner as Example 1. The visibility control performance of Example 2 was good, and the angle at which the image disappeared was 45 degrees.
[0050]
Comparative Example 2
In Example 2 above, the composite lens film and the self-adhesive composite film were applied and bonded to the entire surface without patterning the dry laminating adhesive when the composite lens film and the self-adhesive composite film were bonded together. An optical filter of Comparative Example 2 was obtained in the same manner as in Example 2 except that no air layer was formed between them. The visibility control performance was inferior to that of Example 2, and the angle at which the image was not visible was approximately 70 degrees or more.
[0051]
Example 3
In Example 1 above, the surface of the support film 11 of the composite lens film 10 was colored with a transparent black ink, and the total light transmittance of the composite lens film 10 was set to 75%. A colored type optical filter was obtained. The visibility control performance was good, and the angle at which the image could not be seen was approximately 45 degrees.
[0052]
Example 4
In the production of the self-adhesive composite film of Example 2, a large number of circular dots (diameter: 0.1 mm, thickness: 20 μm) were embossed as a cover film, and the area ratio of the dot portion to the non-dot portion was 1: 1 was applied, and the adhesive for dry laminating when the composite lens film and the self-adhesive composite film were bonded together was applied and bonded to the entire surface without patterning. Otherwise, Example 2 Similarly, an optical filter of Example 4 was obtained. Since this optical filter is embossed on the cover film of the self-adhesive layer, a circular depression is formed on the surface of the self-adhesive layer due to the transfer of the processed surface, and it is attached to the display screen by the self-adhesive force of the self-adhesive layer. When attached, an air layer was formed in the recess between the screen and the visibility control performance comparable to that of Example 2 was obtained.
[0053]
Example 5
As shown in FIG. 4, an example similar to the example 1 except that the cross-sectional shape of the linear protrusion 12 c of the lens film 12 is a square and the dimensions of the top, sides, and valleys are set to 20 μm. 5 optical filters were obtained. The visibility control performance was similar to that in Example 1.
[0054]
Example 6
As shown in FIG. 5, an optical filter of Example 6 was obtained in the same manner as in Example 1 except that a large number of convex lens-shaped convex portions 12 d were closely arranged on the surface of the lens film 12. However, in the convex lens-shaped convex portion 12d, the diameter is set to 150 μm, the height is set to 30 μm, and the radius of the spherical surface is set to about 109 μm, and the convex portion 12d of the lens array formed by a dense arrangement of the convex portions 12d is formed. On the other hand, the convex portions 12d of the adjacent lens rows were molded in a staggered manner. The obtained optical filter of Example 6 had excellent visibility control performance as in Example 1.
[0055]
Example 7
A large number of ultraviolet curable adhesives were printed in the form of circular dots on the surface of the support film 11 of the composite lens film 10 obtained in Example 2, and the adhesive was cured by irradiation with ultraviolet rays. The diameter of the dot portion 25 (see FIG. 6) was 150 μm, the thickness was 30 μm, and the area ratio between the dot portion 25 and the non-dot portion (void portion not printed with adhesive) 25a was 1: 1. The obtained optical filter of Example 7 has an air layer formed on the non-dot portions 25a in a state where the optical filter is pasted on the display screen through the above-mentioned adhesive layer made of dots, and the visibility control performance is as in Example 2. It was comparable.
[0056]
Example 8
When the adhesive of Example 7 is printed in a dot shape, as shown in FIG. 7, a depression 26a is formed on the top of the dot portion 26 made of an adhesive to make the adhesive dot portion 26 a suction cup type. Except for this, an optical filter was obtained in the same manner as in Example 7. The visibility control performance of Example 8 was also excellent as in Example 7.
[0057]
Comparative Example 5
In Example 7, the optical filter of Comparative Example 5 was obtained in the same manner as Example 7 except that the pressure-sensitive adhesive laminated on the lens film was applied to the entire surface without patterning. Since this optical filter has no air layer, the visibility control performance is inferior to that of Example 7.
[0058]
Example 9
In Example 2, the dry laminate adhesive layer 24 applied to the base film 21 of the self-adhesive composite film 20 is formed with circular dots 24b having a diameter of 0.1 mm, as shown in FIG. An optical filter of Example 9 was obtained in the same manner as in Example 2 except that the distribution of dot density in the surface was biased and the character “Kureha” was expressed in a portion where the dot density was low. This visibility control performance was excellent as in Example 2. Furthermore, in the optical filter of Example 9, when the screen was viewed from an angle of 50 degrees or more in the horizontal direction, the above “Kureha” characters were clearly visible. On the other hand, when the screen was viewed from substantially the front, only the image on the screen was visible, and the letters “Kureha” were not visible. Therefore, the optical filter of Example 9 was superior in design to the optical filter of Example 2 and had a high commercial value.
[0059]
【The invention's effect】
  As described above, the optical filter for display screen of the present invention can prevent peeping from the side by being attached to the front surface of the display screen of the liquid crystal display. Moreover,PatternedSince it has an air layer, a visual field control function improves compared with the case where it does not have an air layer, and a viewing angle becomes narrow.Also, with the patterned air layer,Forms a latent image that can be seen from the side but not seen from the frontit canTherefore, the designability and eye catchability can be improved.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a first embodiment.
FIG. 2 is a front view of a use state.
FIG. 3 is a cross-sectional view showing a modification of the first embodiment.
4 is a cross-sectional view showing a modification of FIG.
FIG. 5 is a cross-sectional view showing a modification of FIG.
FIG. 6 is a cross-sectional view of a third embodiment.
FIG. 7 is a perspective view of a fourth embodiment.
FIG. 8 is a perspective view of a fifth embodiment.
[Explanation of symbols]
10: Compound lens film
11: Support film
12: Lens film, 12a, 12b, 12c: Straight ridge
12d: Lens-shaped convex part
20: Self-adhesive composite film
21: Base film
22: Self-adhesive layer
23: Cover film
24: Adhesive layer, 24a: Gap (air layer), 24b: Adhesive dot
25: Adhesive layer, 25a: Cavity (air layer)
26: Dot-shaped convex portion made of adhesive, 26a: depression

Claims (1)

In the optical filter for the display screen for controlling the visible range by attaching it to the front of the display screen of the display as a constituent material, a lens film formed with fine irregularities on one side of the film made of a polymer material,
A pressure-sensitive adhesive for attaching the optical filter to the front surface of the display screen is applied directly on the plane side of the lens film or through a base film made of a transparent thermoplastic polymer material laminated on the plane side, An air layer is provided in at least one layer of the transparent pressure-sensitive adhesive or adhesive layer used for laminating and the transparent pressure-sensitive adhesive layer to be attached to the display screen, and the air layer has a character or figure shape. An optical filter for display screen, which is patterned and forms a latent image whose pattern shape is invisible from the front of the optical filter for display screen.

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