JPH073482B2 - Translucent plastic filter - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a translucent plastic filter used by being attached to a display device such as a CRT display, a fluorescent display tube display, a liquid crystal display, a plasma display, and a projection display. It is a thing.

(Prior Art) Recently, the popularity of office computers and word processors has been remarkably increasing, and there are many opportunities to view the screen of a CRT display device. When looking at such a CRT display device for a long period of time, eye fatigue is severe, and there is a concern about a kind of occupational disease of operators who handle these devices.

In order to reduce such eye fatigue, a filter with a fine surface uneven surface is installed in front of the CRT to suppress regular reflection on the CRT surface due to external light, thereby exhibiting antiglare property. The method of making it proposed is proposed. (JP-A-50-96128, JP-A-55-12107, JP-A-59-116601,
As a method for obtaining such a surface having irregularities, a so-called matte paint in which silica particles are dispersed in a paint is used as a base material surface. It is known to coat the surface of the base material, blow sand on the surface of the base material, roughen it with a grindstone or metal fiber, or transfer the surface of a metal or glass which has been previously matt-treated. The center line average roughness is 0.015 to 0.75 μ (JP-A-59-114501) and the surface ten-point average roughness is 0.1 to
A device having a thickness of 2 μ (Japanese Patent Laid-Open No. 59-116601) is known.

However, conventionally, the matte surface obtained by these methods is
There has been a drawback that the resolution of the transmitted image is lowered as the effect of suppressing the regular reflection due to the external light is improved. Therefore, when used in a filter with anti-glare property,
In order to obtain a sufficient anti-glare effect, the resolution of the displayed image must be sacrificed to some extent, and conversely, when an image of sufficient resolution is obtained, it is reflected on the outside by regular reflection of external light. This resulted in a clear reflection image.

(Problems to be Solved by the Invention) In view of the above situation, the present invention can remove the influence of regular reflection of external light on the surface of a CRT or the like as much as possible without lowering the resolution of a display image. It is intended to provide a filter.

(Means for Solving Problems) The present invention has been made to achieve the above object,
The gist is that it consists of a translucent plastic sheet having a matte surface on at least one side, and the average spacing of the unevenness of the matte surface is 5 to 50 μ, and the gloss retention rate is 25 to 90%. A transparent plastic filter having a haze value of 5% or less.

The present invention will be described below with reference to the drawings of the embodiments, but the first
The figure shows the transparent plastic filter of the present invention, and FIGS. 2 (A), (B), and FIGS. 3 (A) to (D) show partially enlarged cross sections.

In the figure, (1) is a transparent plastic sheet, (2)
Is a matte surface, and in the example of FIG. 2, a circular polarization layer (3) is further formed. This circularly polarizing layer (3) is composed of a linear polarization film (31) and a 1/4 wavelength film (32), which are combined so that the latter crosses the linear polarization axis of the former at an angle of 45 °. It is configured. Although there is a difference between the linear polarization film (31) and the quarter-wave film (32) formed adjacent to each other or separated from each other in FIGS. As a matter of fact, it does not change. In the case of FIG. 3B, the linear polarization film (3
A transparent thin layer or film layer (1 ') is further provided on 1), and a matte surface (2) is formed there.

The light-transmitting plastic filter of the present invention is characterized in that it has a matte surface (2) on at least one surface, for example, the surface on which external light is incident. When the roughness of this surface is expressed by the average interval of irregularities, Furthermore, it is necessary to set the range to 5 to 50 μ.
The average interval of irregularities is a method of displaying roughness described in JIS B-0601-1982. If the average spacing of the irregularities is less than 5μ, specular reflection due to external light cannot be sufficiently suppressed, while if it exceeds 50μ, the irregularities can be identified as sticky. Not only does it hinder the observation of the displayed image, but the reduction in resolution becomes unacceptable.

The translucent plastic sheet used in the present invention is not particularly limited, for example, methacrylic resin, polycarbonate resin, vinyl chloride resin, styrene resin,
AS resin, allyl resin, cellulose resin, etc. are used as the base material.

The thickness of the translucent plastic sheet (1) that can be used in the present invention is not particularly limited, but is 0.2 to 1.2 mm.
The use of a relatively thin sheet has flexibility and appropriate rigidity and is convenient when used along a curved surface.

In order to suppress not only the specular reflection image on the filter surface but also the reflection image generated on the image display surface itself, a translucent plastic sheet (1) having a circular polarization layer (3) is formed as shown in FIG. It is preferable to use.

The circularly polarizing layer (3) in the present invention can be obtained by a combination of the linearly polarizing film (31) and the 1/4 wavelength film (32) as described above. Of these, the linearly polarizing film (31) Is a method of uniaxially stretching a polyvinyl alcohol film or a polyvinyl chloride film, and adsorbing a dichroic iodine or dye thereto, or a conjugated diamine by intramolecular dehydration or intramolecular dechlorination of the film as described above. It can be obtained by a method of forming a heavy bond, a metal polarization film forming method of adsorbing a metal salt of Ag, Au, Hg, Fe or the like on a polymer film and reducing the same.

The 1/4 wavelength film (32) has birefringences n ₁ and n ₂ ,
When the film thickness is d, the wavelength is λ, and n is a positive integer, Although referred to as satisfying the above equation, in the present invention, it is desirable to use a wavelength in the visible region as λ, more preferably 500 to 600 nm with a large visual sensitivity, and thus 100 to 160 nm as a phase difference. If it is good.

Further, an antireflection film may be combined in order to suppress the reflected image on the filter surface more effectively without lowering the resolution. This example is shown in FIG. 3, where (A) is a matte surface (2) with an antireflection film (4) formed on it, and (B).
Indicates that the antireflection film (4) is formed on the surface opposite to the matte surface (2). Further, in FIGS. 6C and 6D, in order to improve the adhesion and the like of the antireflection film (4), a cured film (5) polymerized and cured with a polyfunctional monomer as a main component is used as an underlayer. This is an example in which an antireflection film (4) is formed on this. Such an antireflection film (4) is formed by a single-layer thin film of a substance having a different refractive index from the light-transmitting plastic sheet (1), or as many refractive index interfaces as necessary are formed on this thin film. As described above, a multilayer film is formed by further stacking thin films.

The thin film substance used for such an antireflection film (4) is not particularly limited, but for example, calcium fluoride,
Sodium fluoride, cryolite, lithium fluoride, magnesium fluoride, silicon dioxide, lanthanum fluoride, neodymium fluoride,
Aluminum oxide, cerium fluoride, lead fluoride, magnesium monoxide, thorium oxide, zirconium oxide, lanthanum oxide, silicon monoxide, indium oxide, neodymium oxide, antimony oxide, zirconium oxide, cerium oxide, titanium oxide, zinc sulfide, oxidation Examples thereof include bismuth, zinc selenide, cadmium sulfide, antimony trisulfide, cadmium telluride, silicon, germanium, tellurium, and lead telluride. These can be used alone or in combination of two or more.

The cured film (5) may be formed by applying a monomer to the translucent plastic sheet (1) by a spray method, a dip method, a roller coat method, a flow coat method or the like and polymerizing and curing the monomer. A method of transferring what was previously formed on the template surface to the sheet (1) when polymerizing 1) in the template may be used.

As the polyfunctional monomer used for forming the cured film (5), an esterified product obtained from polyhydric alcohol and (meth) acrylic acid or a derivative thereof, or a polyhydric alcohol, polycarboxylic acid and (meth) acrylic Specific examples include esterified products obtained from acids or their derivatives.

Examples of the polyhydric alcohol include ethylene glycol,
Diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol having an average molecular weight of about 300 to about 1000, propylene glycol, dipropylene glycol, 1,3-propanediol, 2,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol (2,2-dimethyl-1,3-propanediol), 2-ethyl-
1,3-hexanediol, 2,2'-thiodiethanol, 1,4
-Dihydric alcohols such as cyclohexanedimethanol,
Others trimethylolpropane (1,1,1-trimethylolpropane), pentaglycerol (1,1,1-trimethylolethane), glycerol, pentaerythritol (2,
2-bishydroxymethyl-1,3-propanediol), diglycerol, dipentaglycerol and the like.

Particularly preferred compounds obtained from these and (meth) acrylic acid include diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-
Hexanediol diacrylate, trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaglycerol penta (meth) acrylate, dipesitaglycerol hexa (meth) acrylate, etc. Can be raised.

A polyfunctional compound obtained from a polyhydric alcohol, a polycarboxylic acid and (meth) acrylic acid or a derivative thereof is basically a hydroxyl group of a polyhydric alcohol and a polycarboxylic acid and (meth) acrylic acid. It is obtained by reacting a mixture in which both carboxyl groups are finally equivalent.

Examples of the divalent carboxylic acid include aliphatic dicarboxylic acids such as succinic acid, adipic acid and sebacic acid, alicyclic dicarboxylic acids such as tetrahydrophthalic acid and 3,6-endomethylenetetrahydrophthalic acid, phthalic acid and isophthalic acid.
Aromatic dicarboxylic acids such as terephthalic acid, thioglycolic acid, thiodivaleric acid, diglycolic acid or maleic acid, fumaric acid, itaconic acid, etc. or their chlorides, anhydrides and esters can be used.

Further, in order to improve the contrast of the displayed image, it is preferable to reduce the total light transmittance of the translucent plastic sheet or impart the sheet with a light selective absorption performance.

As the light selective absorption performance in this case, the shape of the transmission spectrum in the wavelength region of wavelength 460 to 670 nm is 550 to 6
It is preferable to have a maximum of absorption or transmission of light in the region of 00 nm, and in particular, the shape of the transmission spectrum in the wavelength region of wavelength 460 to 670 nm has a maximum of absorption or transmission of light in the region of wavelength 550 to 600 nm. It is preferable that the light emitting element has the following formula and is substantially symmetrical with respect to the wavelength showing the maximum.

One method for providing such characteristics can be achieved by containing a neodymium compound in a neodymium concentration of 0.2 to 10% by weight so as to have selective absorption at a wavelength of 583 nm. The neodymium compound in this case is preferably one that can be dissolved in a light-transmitting plastic, and depending on the plastic used, it may be a neodymium salt of an organic carboxylic acid such as neodymium nitrate, neodymium methacrylate, neodymium laurate, or 2 A double salt of neodymium composed of various carboxylic acids or a chelate compound such as 2-thenoyltrifluoroacetonato neodymium may be used.

Further, it is more preferable to use one having a selective absorption spectrum corresponding to the emission intensity spectrum of the light source on which the image is displayed, but such performance is obtained by using a light emitting diode whose main wavelength of emission is near 650 nm as a light source. In the case of display, this can be achieved by providing selective absorption performance by absorbing short wavelengths of 600 nm or less as much as possible.

The translucent plastic filter according to the present invention is for easily recognizing an image without reducing the resolution of the image by removing as much as possible external light other than the light source on which the image is displayed, that is, external light. Is extremely effective for

(Example) Below, an example is given and further explained.

Examples 1 to 3 The average interval of the irregularities is 30μ and the ten-point average roughness is 0.6μ, respectively.
A methyl methacrylate partial polymer was added to a casting polymerization cell that was pre-configured to have a plate thickness of 1.5 mm, which consisted of a glass plate with a surface roughness of 0.45 μ, 0.35 μ, mirror surface glass, and a polyvinyl chloride gasket. 100 parts by weight 2,2'-azobis (2,4-dimethylvaleronitrile) 0.01
Inject the syrup mixed with 〃 and incubate at 50 ℃ for 6 hours and then 120
Polymerization was carried out by heating at ℃ for 2 hours. As shown in Table 1, the glossiness, resolution, and visibility of the light-emitting surface when installed on the front of the CRT filter were evaluated.

Comparative Examples 1 and 2 Resin plates were obtained in the same manner as in Examples 1 to 3 except that glass plates having an average unevenness interval of 2 μ and 70 μ and a ten-point average roughness of 0.5 μ were used. The evaluation results of glossiness, resolution, etc. are shown in Table 1.

Example 4 1,6-hexanediol diacrylate 100 parts by weight Polyethylene glycol diacrylate 20 parts by weight benzoin on a matte surface of glass having a surface roughness of 10 μm average roughness of 30 μ and a ten-point average roughness of 0.45 μ Apply a coating material consisting of 1.5 parts by weight of ethyl ether and irradiate it with ultraviolet rays to a thickness of about 20.
A mold glass for casting polymerization with a micron polymer film formed is made to face the untreated glass having a mirror surface so that the film is on the inside, and the periphery is sealed with a soft vinyl chloride gasket to form a mold. It was

In this mold, as a coloring / pigment, neodymium methacrylate 12 parts by weight "Sumiplast Green G" (manufactured by Sumitomo Chemical Co., Ltd.) 0.001 part by weight "Sumiplast Yellow HLR" 0.0008 parts by weight "Cerezu Black G" (manufactured by Bayer) Methyl methacrylate added with 0.08 parts by weight 82 parts by weight 2-hydroxyethyl methacrylate 1 part by weight Styrene 10 parts by weight Lauric acid 5 parts by weight Propylene glycol 2 parts by weight 2,2'-azobisisobutyronitrile 0.1 parts by weight Dioctyl sulfo A base resin raw material consisting of 0.1 part by weight of succinate / sodium salt was injected, and the interval of the mold glass was adjusted so that the resin plate had a thickness of 1 mm, and heated at 50 ° C for 6 hours and then at 120 ° C for 2 hours. Polymerized. After cooling, the resin film peeled from the glass plate was transferred with the film formed on the starting glass and had good adhesion to the substrate. A three-layer antireflection film was further formed on the coated surface of the resin plate thus obtained by the vacuum deposition method in the same manner as in Example 1. (From the resin plate side, the first layer is silicon monoxide, the second layer is zirconium oxide, the third layer is magnesium fluoride, and the thickness of each layer is 500 nm / 4,500 nm / 2,500 nm / 4, respectively.
And When the translucent plastic filter thus obtained according to the present embodiment is installed as a filter on the front surface of the CRT, the resolution and contrast are remarkably excellent as compared with the conventional filter, and specular reflection by external light is provided. I didn't mind the statue either.

Example 5 As coloring dyes and pigments, "Ceresu Black G" (manufactured by Bayer) 0.028% by weight, "Sumiplast Green G" (manufactured by Sumitomo Chemical Co., Ltd.) 0.0004% by weight, "Sumiplast Yellow"
HLR "0.5 mm thick acrylic resin sheet with 0.00028% by weight added (80% methyl methacrylate and styrene
/ 20 was copolymerized in the same cell for casting polymerization as in Example 1), and a linearly polarized film having a thickness of 0.18 mm (manufactured by Sanritsu Electric Co., Ltd.)
SCC2M-18) and the same 1/4 wavelength plate as in Example 1 are laminated and integrated by intersecting the polarizing film at an angle of 45 ° with respect to the stretching direction.
A transparent plastic sheet was obtained. When the filter using the sheet according to this example was installed in front of the CRT, it was very easy to see.

The light transmission characteristics of Examples 4 and 5 were measured, and the results shown in FIG. 4 were obtained.

The evaluation method in the present invention is as follows.

<Gloss retention> The surface glossiness at a 60 degree angle was measured using a digital gloss meter (GM-30) manufactured by Murakami Color Research Laboratory.

<Resolution> A screen line number meter made by the Institute of Printing Science is placed at 30 cm under a fluorescent lamp of 30 W, and a line that can be identified per inch when seen through a sample set at 5 cm above this screen line number meter. The number was visually measured.

<Transmittance> Transmittance was measured using "Hitachi Spectrometer Model 330".

<Haze value> The haze value was measured according to JIS K-6714.

(Effects of the Invention) The present invention has the constitution as described in detail above,
The matte surface having an average interval of μ irregularities does not decrease the resolution and can effectively remove the influence of external light, and especially the circular polarizing layer, antireflection film, light selective absorption performance, etc. By having them together, there is an advantage that an extremely excellent translucent plastic filter can be obtained.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a light-transmitting plastic filter of the present invention, FIGS. 2 (A) and 2 (B) are enlarged sectional views showing the same embodiment of the present invention, and FIG. FIG. 4 is an enlarged cross-sectional view showing another example of the present invention, and FIG. 4 is a graph showing the spectral transmittance of Examples 4 and 5 of the present invention. (1) …… Translucent plastic sheet (2) …… Matte surface (3) …… Circular polarizing layer (31) …… Linear polarizing film (32) …… 1/4 wavelength film (4) …… Reflecting Prevention layer (5) ... Cured film

Claims (11)

[Claims] 1. A light-transmissive plastic sheet having a matte surface on at least one side, the mean interval of irregularities on the matte surface is 5 to 50 μ, the gloss retention is 25 to 90%, and the haze value is A transparent plastic filter characterized by being 5% or less. 2. A translucent plastic filter according to claim 1, wherein a translucent plastic sheet having a thickness of 0.2 to 1.2 mm is used. 3. The translucent plastic filter according to claim 1, wherein a translucent plastic sheet having a circularly polarizing layer is used. 4. The translucent plastic filter according to claim 1, 2, or 3, wherein an antireflection film is formed on at least one surface. 5. The translucent plastic filter according to claim 4, wherein the antireflection film is formed on a cured film which is polymerized and cured with a polyfunctional monomer as a main component. 6. A translucent plastic sheet having a total light transmittance of 20 to 80% is used, and the scope of claim 1, claim 2, claim 3, claim 4, or claim 5. The translucent plastic filter according to item 5. 7. A light-transmissive plastic sheet having a light selective absorption performance is used, and the first invention is characterized.
The light-transmissive plastic filter according to item (2), item (3), item (4), item (5), or item (6). 8. A light-transmissive plastic sheet having a light-selective absorption property in which the shape of the transmission spectrum in the wavelength region of 460 to 670 nm has a maximum of absorption or transmission of light in the wavelength region of 550 to 600 nm. The transparent plastic filter according to claim 7, characterized in that 9. The shape of the transmission spectrum in the wavelength range of 460 to 670 nm has a maximum of absorption or transmission of light in the range of 550 to 600 nm, and is substantially symmetrical with the wavelength showing this maximum as an axis. The transparent plastic filter according to claim 7, wherein a transparent plastic sheet having a light selective absorption performance is used. 10. A translucent plastic sheet having a light selective absorption performance having a selective absorption spectrum corresponding to an emission intensity spectrum of a light source on which an image is displayed is used. The translucent plastic filter described in the item. 11. A translucent plastic sheet having a light selective absorption performance at a wavelength of 583 nm by containing a neodymium concentration of 0.2 to 10% by weight, wherein the light transmissive plastic sheet is used. Translucent plastic filter.