JP2002333502A - Antireflection window plate for display cover of portable device having display and portable device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that, when a conventional antireflection material is applied, it takes a long time to form a transparent electrically conductive thin film and a low refractive index layer resuling in low working speed, the corrosion resistance of the transparent electrically conductive thin film is not satisfactory and reflectance in the whole visible light region is not constant. SOLUTION: The problems can be solved by stacking a hard coat layer 5 and an antireflection layer 6 (comprising layers 6a and 6b different from each other in refractive index) in this order on the top surface of a transparent plate 2 having a finely rugged face 3 with protrusions 3a formed at a pitch below the wavelength of light on the undersurface thereof. A patterned layer may be disposed at a proper position, e.g. between the transparent plate 2 and the hard coat layer 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a window plate for a display unit cover suitable for being provided on an observation side surface of a display of various portable devices. The present invention also relates to a portable device with a display having such a window for a display unit cover.

[0002]

2. Description of the Related Art There are various types of portable devices having a display, that is, a display unit. For example, a calculator, a personal computer, a portable label printer, a mobile phone, an IC recorder, a CD player, a DVD player, an MD player, or a music player for recording on other media, a video tape recorder, a video camera, or a digital camera. is there. Besides these, it is small,
There are various types of devices that can be carried and held by hand, and there are many types with a display (eg, electric rice cookers, electronic pots). In the present invention, the above information is stored or reproduced. The display unit is intended to be one that has the existence value, and the display unit excludes the display unit using mechanical means.

[0003] The displays of these portable devices usually have a backlight,
Alternatively, a display of a type that improves visibility by illuminating with a front light is used, and a liquid crystal display is typically used. These portable devices are limited by the amount of power that can be used to illuminate the display because they use a battery as a power source. Various measures have been taken to use it.

[0004] Further, since these displays are portable devices, they may be inadvertently touched by hand or hit against other articles, so that the display portion is covered with a transparent cover plate. However, even in this cover plate, light needs to be transmitted without being reflected. Of course, since the cover plate is used, it is necessary to pay attention to the illumination on the observer side and the reflection of external light such as sunlight, which also impair the visibility of the display.

Conventionally, various antireflection measures have been proposed to solve such problems. For example, Japanese Patent Application Laid-Open No. 9-80205 discloses a transparent base material, a hard coat layer, and a two-layer structure. An anti-reflection member in which an anti-reflection optical thin film is formed in order is described, and SnO ₂ , ZnO, In ₂ O ₃ , or IT
O, and examples of the optical thin film for preventing reflection of the second layer, a low SiO ₂ and a refractive index than the optical thin film for preventing reflection of the first layer M
gF ₂ or the like is used to eliminate the susceptibility to damage by the hard coat layer, to prevent electrification by the first anti-reflection optical thin film, and to prevent reflection by the first and second anti-reflection optical thin films. It is said to be done.

However, in the antireflection member having the above structure, the first and second antireflection optical thin films each need to have a thickness of several tens of nanometers. Attempting to form it has the disadvantage of being time consuming. In addition, although a transparent conductive thin film such as ITO is excellent in transparency, it has a disadvantage that corrosion resistance is not sufficient.
Furthermore, in the antireflection member having the above-described configuration, the reflectivity on the red light side and the blue light side in the visible light region (wavelength 450 nm to 650 nm) at which humans perceive dazzling does not decrease sufficiently uniformly, that is, the wavelength of incident light and Since the antireflection property changes depending on the incident angle, the reflectance does not decrease in the entire visible light range, and the color changes and glare remains. In addition, there is no thorough preparation for scratches and stains generated during handling.

[0007]

Therefore, in the present invention, when the above-mentioned conventional anti-reflection material is applied,
It takes time to form the transparent conductive thin film and low refractive index layer,
An object of the present invention is to solve the problems that the processing speed is slow, the corrosion resistance of the transparent conductive thin film is not sufficient, and that the reflectance in the entire visible light range is not constant.

[0008]

For example, in a fine uneven film having a fine uneven pattern with a pitch equal to or less than the wavelength of light formed on the surface of a transparent acrylic resin film or the like, the acrylic resin occupies most at the bottom of the uneven surface. Approaching the refractive index of the resin itself (about 1.49) without limit,
The closer to the surface side of the irregularities, the lower the ratio of the acrylic resin and the higher the ratio of air instead. Therefore, the refractive index decreases, and the refractive index of air (1.0) near the outermost surface. It is known that the effect is as close as possible and as if a large number of layers in which the refractive index of light continuously changes were laminated. The present invention intends to solve the above-mentioned problems by utilizing such special fine irregularities.

According to a first aspect of the present invention, there is provided a display of a portable device having a display section, wherein at least one side of a transparent plate has an uneven surface on which a myriad of fine unevennesses having a pitch equal to or less than the wavelength of light are formed. The present invention relates to an antireflection window plate for a unit cover. 2. The portable device having a display unit according to claim 1, wherein the transparent plate has an uneven surface on one side of the transparent plate on which innumerable fine unevenness having a pitch equal to or less than the wavelength of light is formed. The present invention relates to an antireflection window plate for a display unit cover. According to a third aspect, in the first aspect, a portable device having a display portion, characterized in that the transparent plate has, on both sides, an uneven surface on which innumerable fine unevenness with a pitch equal to or less than the wavelength of light is formed. The present invention relates to an antireflection window plate for a display unit cover. A fourth invention is directed to any one of the first to third inventions, wherein a pattern layer is laminated on one or both sides of the transparent plate, for a display unit cover of a portable device having a display unit. The present invention relates to an antireflection window plate. According to a fifth aspect of the present invention, in any one of the first to fourth aspects of the invention, a hard-coat layer is laminated on one or both sides of the transparent plate. The present invention relates to an anti-reflection window plate for use. According to a sixth aspect of the present invention, in any one of the first to fifth aspects, an antireflection layer including a plurality of thin film layers having different refractive indices is sequentially laminated on one or both sides of the transparent plate. The present invention relates to an antireflection window plate for a display unit cover of a portable device having a display unit. A seventh invention relates to a portable device having a display unit, wherein the antireflection window plate according to any one of the first to sixth inventions is provided on an observation side on the display unit.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An antireflection window plate (hereinafter simply referred to as a window plate) 1 for a display unit cover of a portable device having a display unit according to the present invention is, for example, shown in FIG. As shown in (1), an uneven surface 3 (hereinafter, may be simply referred to as an uneven surface) in which a myriad of fine unevenness 3aa having a pitch equal to or less than the wavelength of light is formed on the surface of a substrate of a transparent plate 2 such as plastic or glass. ), And as shown in FIG.
One having the uneven surface 3 only on one side, and one having the uneven surfaces 3 and 3 ′ on both surfaces as shown in FIG.

When the uneven surface 3 on which the fine unevenness 3a is formed faces the display unit side of a portable device having a display unit, the window plate 1 effectively transmits light from the display unit to the observation side. In addition, when the uneven surface 3 is arranged facing the observation side, a function of suppressing reflection of external light can be exhibited. If the window plate 1 has the uneven surfaces 3 and 3 'in which the fine unevenness 3a and 3a' are formed on both surfaces, both functions can be exhibited.

The window plate 1 has a transparent layer, preferably a layer of a cured product of a curable resin, other than a structure having an uneven surface 3 in which fine unevenness 3a is formed directly on the surface of the transparent plate 2 itself. It may be laminated on the plate 2 and have an uneven surface in which fine unevenness 3a is formed on the surface of those layers. As described later, a molding die and an ionizing radiation-curable resin composition are used. The formed layer of the cured product of the ionizing radiation-curable resin composition having the uneven surface 3 in which the fine unevenness 3a was formed on the transparent base material was laminated, in other words, the uneven surface was formed indirectly. It may be something.

When the window plate 1 has uneven surfaces 3 and 3 'on both surfaces, one is formed directly on the transparent plate 2 and the other is formed on the transparent plate 2 indirectly. In other words, a structure in which fine irregularities 3 a are formed on a transparent layer different from the transparent plate 2 may be laminated on the transparent plate 2.

The window plate 1 may have a pattern layer 4 formed by printing or the like. The pattern layer 4 is not limited to simply a design point of view, and may have a shape such as a character, a symbol, a line, a picture or a photograph alone, or a combination of any of these. It may be configured. Printing for forming the pattern layer 4 can be performed by known printing means such as screen printing, transfer, ink jet, or the like. When the window plate 1 is formed larger than the display unit, the pattern layer 4 has a function of covering a part of the window plate 1 and shielding the periphery of the display unit so as to show only the display unit. You may. Therefore, a case where the periphery of the window plate 1 is simply shielded in a frame shape is also included in the concept of the pattern layer 5 here. The pattern layer 4 may be laminated for the purpose of indicating the name of the device or displaying the item name of the content displayed on the display unit.

As a variation of the position where the pattern layer 5 is laminated and the surface on which the pattern layer 5 is laminated, as shown in FIG.
One having an uneven surface 3 on one side of which fine unevenness 3a is formed, and a pattern layer 4 laminated on the opposite surface, and FIG.
As shown in FIG. 2, there is a structure in which the pattern layer 4 is laminated on only one of the uneven surfaces 3 having the fine unevenness 3a formed on both surfaces.

If necessary, a pattern layer may be laminated on the uneven surface 3 in place of the pattern layer 4 on the lower surface as shown in FIG. May be laminated. In FIG. 2B, the pattern layer may be laminated not only on one side but also on both sides. When another layer as described later is added to the window plate 1, the pattern layer 5 may be laminated on those layers. The layer above the pattern layer 5 is transparent, If it is possible to see through these layers, it may be laminated between any of the laminated structures, or may be laminated on the lowermost surface. Of course, the pattern layer 4 may be laminated on the uppermost surface.

The window plate 1 may have a hard coat layer 5 laminated thereon. As shown in FIG. 3A, the window plate 1 has an uneven surface 3 having fine unevenness 3a formed on one surface. 3B, a hard coat layer 5 is laminated on the opposite surface, or as shown in FIG. 3B, a hard coat layer is formed only on one of the uneven surfaces 3 and 3 'having fine unevenness 3a, 3a' formed on both surfaces. 5 are laminated. The hard coat layer 5 is usually laminated on the outermost surface of the window panel 1, and imparts physical durability or chemical durability to the surface of the window panel 1, or improves the properties thereof. .

It is natural that the hard coat layer 5 is laminated on one side which is the outer surface of the window plate 1.
It is planned to be installed on a door that can be opened or closed, or to be installed as a door that can be opened and closed. A hard coat layer may be laminated on both sides. The hard coat layer 5 may be laminated on the outermost surface of various types of window plates 1 as described with reference to FIGS. 1 and 2. Therefore, for example, in FIG. 3A or 3B, the pattern layer 4 may be interposed between the hard coat layer 5 and the transparent plate 3.

Although the hard coat layer 5 is usually laminated on the outermost surface, an antireflection layer 6 may be further laminated. In this case, the lower layer of the anti-reflection layer 6 may have an uneven surface on which the fine unevenness 3a is formed, but generally does not have the uneven surface. The specific anti-reflection layer 6 has a laminated structure of a plurality of layers as shown by reference numerals 6a and 6b in FIG. 4, and preferably includes each layer of the laminated structure, that is, the layers 6a and 6b in FIG. Are different from each other in refractive index to provide anti-reflection properties.

As the transparent plate 2 constituting the window plate 1 of the present invention, a transparent plate having transparency and smoothness and free from foreign matter is preferable, and has a mechanical strength for processing and use of the product. Are preferred.

Preferred materials for the transparent plate 2 include cellulose diacetate, cellulose triacetate, cellulose acetate butyrate, polyester, polyamide, polyimide, polyethersulfone, polysulfone, polypropylene, polymethylpentene, polyvinyl chloride, and polyvinyl acetal. , Polyether ketone, polymethyl methacrylate, polycarbonate, or a thermoplastic resin such as polyurethane, or glass.

In the case of a photographic film coated with a photographic emulsion, a polyester which is often used is preferred in terms of mechanical strength and coating suitability. Cellulose triacetate and the like are preferable in terms of high transparency, no optical anisotropy, and low refractive index. Polycarbonate is preferred in terms of transparency and heat resistance.

The thickness of the transparent plate 2 is 100 μm to 2 μm.
mm, more preferably 200 μm or more. Even when the window plate 1 has a laminated structure of various layers,
It is preferable that the thickness of the entire window plate 1 is in the above numerical range.

In order to improve the adhesion of the transparent plate 2 to the upper surface or the layers formed on the upper surface and the lower surface, various treatments that can be usually performed, such as corona discharge treatment, oxidation treatment, and the like, are used. In addition to the physical treatment described above, a chemical treatment by applying an anchor agent (also called a primer agent) may be performed in advance to form the anchor layer.

The resin constituting the anchor layer is a polyester resin, a polyurethane resin, a polyethyleneimine resin, a polybutadiene resin, an acrylic resin, a polycarbonate resin, a vinyl chloride / vinyl acetate copolymer, or the like. One or two or more of these resins are dissolved in an appropriate solvent to form a paint or ink, which is applied or printed to form an anchor layer. In addition, an anchor layer can also be formed using an alkyl titanate-based anchoring agent.

The uneven surface 3 having the fine unevenness 3a is most efficiently formed by using a molding die having an inverse shape of the fine unevenness 3a as a mold surface.
It is formed by pressing a molding die in a molten state at the time of manufacturing a glass plate or in a state where a glass plate once manufactured is melted again. When the transparent plate 2 is made of a thermoplastic resin, the uneven surface 3 is formed by using a molding die in a molten state or a liquid state when the transparent plate 2 is manufactured.

Alternatively, in the case of injection molding of plastic or casting polymerization of acrylic resin, etc., fine irregularities 3 are formed on the inner surface of the mold.
a, the molten resin is injected or a monomer or a prepolymer is injected to form the uneven surface 3.
Can be formed. In addition, during the injection molding or the casting polymerization of the acrylic resin, fine irregularities 3a are formed on the inner surface of the mold.
A similar result can be obtained by arranging a film-like material having

The most efficient formation of the uneven surface 3 having the fine unevenness 3a is performed by a method using an ionizing radiation-curable resin composition as described below. 3, a transparent layer formed on the surface of a layer made of a cured product of the ionizing radiation-curable resin composition is laminated or formed on a transparent substrate different from the transparent plate 2, for example, a thin transparent film with a rough surface. By laminating a transparent layer on which the transparent layer 3 is formed on the transparent plate 2. In the case of lamination, it is good to carry out via a transparent adhesive layer as needed.

As the ionizing radiation-curable resin composition, the curing speed is high when the uneven surface 3 is formed by a casting method using a molding die, and the curing is performed so that the surface of the transparent layer is not damaged. Those having high scratch resistance later are preferred. As the ionizing radiation-curable resin composition, those having a hardness after curing of “H” or more in a pencil hardness test shown in JIS K5400 are more preferable. In addition, the refractive index of light of the transparent layer is preferably low in order to exhibit antireflection performance, but for long-term use, surface durability, particularly abrasion resistance is required, and hardness is high. Therefore, it is necessary to increase the density to increase the hardness. Therefore, the refractive index of light of the transparent layer is 1.4 to
It is 1.7, more preferably 1.6 or less.

The ionizing radiation-curable resin composition is prepared by appropriately mixing a prepolymer, an oligomer and / or a monomer having a polymerizable unsaturated bond or an epoxy group in the molecule. Ionizing radiation refers to electromagnetic waves or charged particle beams having energy quanta that can polymerize or crosslink molecules, and usually use ultraviolet rays or electron beams.

Examples of prepolymers and oligomers in the ionizing radiation-curable resin composition include unsaturated polyesters such as condensates of unsaturated dicarboxylic acids and polyhydric alcohols, polyester methacrylates, polyether methacrylates, polyol methacrylates, melamines. Methacrylates such as methacrylate, polyester acrylate,
Examples include acrylates such as epoxy acrylate, urethane acrylate, polyether acrylate, polyol acrylate, and melamine acrylate, and cationic polymerization type epoxy compounds.

Examples of the monomer in the ionizing radiation-curable resin composition include styrene monomers such as styrene and α-methylstyrene, methyl acrylate, and acrylic acid-2-
Acrylic esters such as ethylhexyl, methoxyethyl acrylate, butoxyethyl acrylate, butyl acrylate, methoxybutyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, methoxyethyl methacrylate, methacrylic acid Methacrylic esters such as ethoxymethyl, phenyl methacrylate and lauryl methacrylate; 2- (N, N-diethylamino) ethyl acrylate; 2- (N, N-dimethylamino) ethyl acrylate; -2 acrylic acid -(N, N-dibenzylamino) methyl, unsaturated substituted substituted alcoholic esters such as 2- (N, N-diethylamino) propyl acrylate, unsaturated carboxylic acid amides such as acrylamide and methacrylamide, ethylene Guri Diacrylate, propylene glycol diacrylate, neopentyl glycol diacrylate, 1,6-hexanediol diacrylate, triethylene glycol diacrylate, and other compounds, dipropylene glycol diacrylate, ethylene glycol diacrylate, propylene glycol dimethacrylate, diethylene glycol Polyfunctional compounds such as dimethacrylate and / or polythiol compounds having two or more thiol groups in the molecule, for example, trimethylolapropanetrithioglycolate, trimethylolapropanetrithiopropylate, pentaerythritol tetrathioglycol Rate and the like.

Usually, as the monomer in the ionizing radiation-curable resin composition, one or a mixture of two or more of the above compounds is used as necessary. To provide suitability, it is preferred that the prepolymer or oligomer be 5% by weight or more and the monomer and / or polythiol compound be 95% by weight or less.

When flexibility is required when the ionizing radiation-curable resin composition is cured, the amount of the monomer may be reduced or an acrylate monomer having one or two functional groups may be used. When abrasion resistance, heat resistance, and solvent resistance are required when the ionizing radiation-curable resin composition is cured, an ionizing radiation-curable resin such as an acrylate monomer having three or more functional groups is used. Composition design is possible.

Here, one having one functional group includes 2-hydroxyacrylate, 2-hexyl acrylate and phenoxyethyl acrylate. 2 functional groups
As ethylene glycol diacrylate,
1,6-hexanediol diacrylate is exemplified. As a compound having three or more functional groups, trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate,
And dipentaerythritol hexaacrylate.

In order to adjust physical properties such as flexibility and surface hardness when the ionizing radiation-curable resin composition is cured, a resin that is not cured by ionizing radiation irradiation is added to the ionizing radiation-curable resin composition. Can also. Examples of specific resins include the following. Thermoplastic resins such as polyurethane resin, cellulose resin, polyvinyl butyral resin, polyester resin, acrylic resin, polyvinyl chloride resin, and polyvinyl acetate. Above all, addition of a polyurethane resin, a cellulose resin, a polyvinyl butyral resin or the like is preferable from the viewpoint of improving flexibility.

When the ionizing radiation-curable resin composition is cured by ultraviolet irradiation, a photopolymerization initiator or a photopolymerization accelerator is added. As the photopolymerization initiator, in the case of a resin system having a radically polymerizable unsaturated group, acetophenones, benzophenones, thioxanthones, benzoin, benzoin methyl ether or the like is used alone or as a mixture. Further, in the case of a resin having a cationically polymerizable functional group, an aromatic diazonium salt, an aromatic sulfonium salt, an aromatic iodonium salt, a metaceron compound, a benzoinsulfonic acid ester, or the like is used alone or as a mixture as a photopolymerization initiator. . The addition amount of the photopolymerization initiator is 0.1 to 1 with respect to 100 parts by weight of the ionizing radiation-curable resin composition.
0 parts by weight.

The ionizing radiation-curable resin composition may be used in combination with the following organic reactive silicon compound. One of the organosilicon compounds can be represented by the general formula R _m Si (OR ′) _n , R and R ′ represent an alkyl group having 1 to 10 carbon atoms, and the suffix m of R and the suffix n of R ′ Means m
+ N = integer satisfying the relationship of 4.

Specifically, tetramethoxysilane, tetraethoxysilane, tetra-iso-propoxysilane, tetra-n-propoxysilane, tetra-n-butoxysilane, tetra-sec-butoxysilane, tetra-tert-butoxysilane , Tetrapentaethoxysilane, tetrapenta-iso-propoxysilane, tetrapenta-n-propoxysilane, tetrapenta-n-
Butoxysilane, tetrapenta-sec-butoxysilane, tetrapenta-tert-butoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltributoxysilane, dimethyldimethoxysilane,
Dimethyldiethoxysilane, dimethylethoxysilane,
Dimethylmethoxysilane, dimethylpropoxysilane,
Examples include dimethylbutoxysilane, methyldimethoxysilane, methyldiethoxysilane, hexyltrimethoxysilane, and the like.

The organosilicon compound 2 which can be used in combination with the ionizing radiation-curable resin composition is a silane coupling agent. Specifically, γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ- (2-aminoethyl) aminopropylmethyldimethoxysilane, β- (3,4-
Epoxycyclohexyl) ethyltrimethoxysilane,
γ-aminopropyltriethoxysilane, γ-methacryloxypropylmethoxysilane, N-β- (N-vinylbenzylaminoethyl) -γ-aminopropylmethoxysilane hydrochloride, γ-glycidoxypropyltrimethoxysilane, aminosilane , Methylmethoxysilane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, hexamethyldisilazane, vinyltris (β-methoxyethoxy) silane, octadecyldimethyl [3-
(Trimethoxysilyl) propyl] ammonium chloride, methyltrichlorosilane, dimethyldichlorosilane and the like.

The organosilicon compound 3 which can be used in combination with the ionizing radiation-curable resin composition is an ionizing radiation-curable silicon compound. Specific examples include a plurality of functional groups that react and crosslink by irradiation with ionizing radiation, for example, an organosilicon compound having a molecular weight of 5,000 or less and having a polymerizable double bond group, and more specifically, one end. Examples include vinyl-functional polysilanes, vinyl-functional polysilanes at both ends, vinyl-functional polysiloxane at one terminal, vinyl-functional polysiloxane at both terminals, and vinyl-functional polysilane or vinyl-functional polysiloxane obtained by reacting these compounds.

More specifically, the following compounds are used.

[0043]

Embedded image

Other examples of the organosilicon compound that can be used in combination with the ionizing radiation-curable resin composition include (meth) such as 3- (meth) acryloxypropyltrimethoxysilane and 3- (meth) acryloxypropylmethyldimethoxysilane. Acryloxysilane compounds and the like can be mentioned.

The shape of the fine irregularities 3a having a pitch equal to or less than the wavelength of light formed on the upper surface of the transparent layer is shown in FIGS.
In addition to the shape of the fine unevenness 3a at the upper edge of the cross section as exemplified in FIG. 5, the top of the cross section as shown in FIG. There may be a shape having a shape that becomes narrower as going upward, a shape having a triangular wave shape as shown in FIG. 5C, or a shape having a rectangular wave shape as shown in FIG. 2D.

Among these, the depth varies depending on the location of the fine unevenness 3a. FIGS. 5 (a), 5 (b) and 5 (c).
Such a cross-sectional shape is preferable. When such a cross-sectional shape is used, the property that the refractive index of light changes depending on the position in the thickness direction of the transparent layer is provided.

Of these, the one shown in FIG. 5D has the same proportion of the transparent layer because the area of the horizontal cut surface does not change at any height, and the upper part of the wave The refractive index of light does not change between the lower side and the lower side. However, a layer having a constant and predetermined refractive index can be formed by determining the pitch and the width of the wave. In addition, there may be a shape as shown in FIG. 5 (e) which is not upwardly tapered, but it is difficult to release when manufacturing using a molding die, which is not preferable.

The cross-sectional shape of the fine irregularities 3a is, for example, as described above. When the transparent layer having these cross-sectional shapes is observed from the side having the fine irregularities 3a, the arrangement of the fine irregularities 3a is as follows. As shown in the perspective view of FIG. 6A, when a concave portion is noticed, a parallel groove 3b (a parallel partition 3d when a convex portion is noticed) is formed, or as shown in FIG. 6B or FIG. ) May be formed by arranging them in a plane as shown in a diagram viewed from above (concentric circles indicate contour lines). Both types have anti-reflection properties, but the groove-type type shown in FIG. 6A has directionality, so that the reflectance can change depending on the direction of incident light. On the other hand, a two-dimensionally arranged shape as shown in FIG. 6B or 6C is preferable because it has virtually no directionality.

Although the shape of the fine unevenness 3a itself is various, the pitch (= period) of the wave of the unevenness appearing in the cross-sectional shape is a minute one less than the wavelength of light. In normal applications, this light refers to visible light, and therefore "fine below the light wavelength" refers to 400 nm or less. Although there is no particular lower limit, it is preferably at least 50 nm in consideration of the accuracy of the mold.

The greater the difference in wave height in the cross-sectional shape of the fine irregularities 3a, the lower the reflectance and the effect of preventing reflection. Therefore, the difference in height is preferably 100 nm or more. There is no particular upper limit, but a normal pitch of 50 nm to 400 nm
Assuming nm, it is preferably about 100% to 200% of the pitch value, and is about 100 nm to 500 nm.

It is efficient to prepare and duplicate such fine irregularities 3a by preparing a mold for duplication. In order to produce a shaping mold, first, an appropriate base material is used as a base material of a mold, and a photosensitive resin is laminated on the base material, and this is exposed by a laser light interference method. In addition, as a material obtained by laminating a photosensitive resin on a base material, a commercially available photosensitive material for producing a relief hologram can be used.

The exposure is performed by dividing the laser beam into two or more beams and causing interference, thereby obtaining a cured portion and an uncured portion having a pitch equal to or less than the wavelength of the light. After the exposure, the developing method according to the type of the photosensitive resin, if it is a negative photosensitive resin, development is performed by removing the uncured portion with a specific solvent or the like, and the development is performed. A prototype of a molding die having an uneven surface with irregularities is obtained.

Since the obtained prototype is made of a polymer having a relatively small molecular weight in order to facilitate the formation of irregularities, it has insufficient durability against a solvent, and is brittle. It is not preferable to use duplicates again.

Then, the prototype obtained above is plated with a metal such as nickel and peeled off to form a first metal mold, and the first metal mold is used or It is preferable to perform plating on the metal mold of No. 1 to form several second metal molds, and to duplicate using the obtained second metal mold. The use of the resulting mold avoids the problem of mold damage and wear. Note that these metal molds obtained by plating are referred to as metal stampers.

More preferably, the shape of the mold surface obtained in this manner is formed on a roller surface, and if necessary, a mold roller or a mold roller (multi-faced on the same plate surface) is used. Use of a mold roller whose shape is continuously formed in the surface length direction and the circumferential direction of the roller is suitable for continuous production. Therefore, the mold for shaping may be a sheet-like mold, a plate-like mold, or a roller-like mold.

When the shape of the mold surface is duplicated, the original mold and the second metal mold have the same shape, and the original mold and the first metal mold have an inverse mold relationship to each other. . Further, the shape of the fine irregularities of the antireflection material and the shape of the fine irregularities of the mold surface on the mold for manufacturing the antireflection material are reversed. Therefore, in order to obtain a desired shape as an antireflection material, it is preferable to further form a metal mold by plating to reverse the shape of the fine unevenness, if necessary. However, when the cross-sectional shape of the fine unevenness is a sinusoidal curve, there is an exceptional case where there is substantially no difference between the original mold shape and the inverted mold shape. In this specification, the shape of the fine irregularities 3a on the mold surface of the shaping mold is set so that the anti-reflective material can obtain the desired shape of the fine irregularities 3a in the anti-reflective material except for the above-mentioned exceptional cases. It is assumed that it is formed in a shape.

In order to form an uneven portion composed of fine unevenness 3a on the upper surface of the transparent layer using the ionizing radiation-curable resin composition, a transparent base material and the above-described mold are prepared.
Both are laminated via a liquid ionizing radiation-curable resin composition. In the case of this lamination, the ionizing radiation-curable resin composition may be laminated on the transparent substrate side, and then laminated with the molding die, or conversely, the ionizing radiation-curable resin may be laminated on the molding die. The composition may be laminated before being laminated with the transparent substrate. Alternatively, the transparent substrate and the molding die may be laminated while supplying the ionizing radiation-curable resin composition between the transparent substrate and the molding die.

After lamination, the ionizing radiation-curable resin composition between the transparent substrate and the mold is irradiated with ionizing radiation. When the ionizing radiation is ultraviolet light, the irradiation is preferably performed from the side of the transparent substrate, but may be performed from the side of the mold if the mold is transparent. When the ionizing radiation is an electron beam, the electron beam has excellent permeability to the substance,
Irradiation from any source may be used as long as the electron beam can be transmitted.

The irradiation of the ionizing radiation cures the ionizing radiation-curable resin composition to form a cured product and adheres to the transparent substrate. Therefore, after the irradiation of the ionizing radiation, the ionizing radiation-curable resin composition By releasing the cured product from the molding die together with the transparent substrate, a transparent layer comprising a cured product of a transparent ionizing radiation-curable resin composition on the transparent substrate and having fine irregularities formed on the surface And a transparent substrate are laminated.

In the above, it is efficient that the irradiation of the ionizing radiation is performed only once. However, while the molding die, the ionizing radiation-curable resin composition, and the molding die are laminated, Irradiating with ionizing radiation for a long time is not always efficient. Therefore, for the purpose of shortening the time during which the above three members are laminated, by relatively weak irradiation of ionizing radiation, pre-curing and pre-adhesion are performed.
The pre-cured and pre-bonded ionizing radiation-curable resin composition is separated from the mold for mold release together with the transparent substrate and separated, and for the separated pre-cured and pre-bonded ionizing radiation-curable resin composition, When relatively strong irradiation of ionizing radiation is performed to completely cure the ionizing radiation-curable resin composition and completely adhere to the transparent substrate, a molding die, an ionizing radiation-curable resin composition, and a molding die There is an advantage that the time required to maintain the state in which the three members of the mold are stacked is short,
Manufacturing efficiency is improved. After that, irradiation of ionizing radiation for complete curing and complete adhesion with the transparent substrate can be performed for a long time without reducing the processing speed by extending the irradiation zone while running the irradiation object. This is because that.

FIG. 7 shows a state in which a mold roller is used to manufacture an apparatus 10 for continuously manufacturing an uneven surface having fine unevenness. In FIG. 7, a transparent substrate (which may be the transparent plate 2 or a thin film different from the transparent plate 2) 2a is unwound from the upper left side as viewed in the figure, and the nip roller 11a After being guided between the mold rollers 12 and making a half turn around the upper side of the mold rollers 12, the paper passes between the nip rollers 11b and is discharged rightward as viewed.

The mold roller 12 is driven so as to rotate in the clockwise direction indicated by an arrow in the mold roller 12, and the nip rollers 11a and 11b rotate together with the rotation of the mold roller. (Indicated by an arrow inside). Further, a brake is installed on the unwinding side of the transparent base material 2a, and the tension during running can be adjusted by a hoisting motor installed on the discharge side. The tension between the nip rollers 11a and 11b is kept constant.

Directly below the mold roller 12 is a die head 13.
The die head 13 has a liquid reservoir 1 inside.
4. It has a slit 15 above and is configured to be supplied with an ionizing radiation-curable resin composition 17 from the outside via a pipe 16. A required amount of the ionizing radiation-curable resin composition 17 is extruded upward from the slit 15 in accordance with the travel of the transparent substrate 2a, applied to the surface of the mold roller, and ionized radiation is also applied to the concave portion 12a of the mold roller 12. When the curable resin composition 17 is filled and passes between the nip roller 11a and the mold roller, the application amount is regulated.

An ionizing radiation irradiating device 18 is provided above the mold roller 12, and is irradiated with ionizing radiation when passing under the irradiating device 18. The ionizing radiation curable resin composition on the transparent substrate 2 a is provided. Is cross-linked and cured, and the transparent layer and the transparent substrate 2a
And adhere. Thereafter, the cured transparent layer is released together with the transparent substrate and wound up.

When laminating the transparent substrate 2a, it is sufficient that at least the concave portion 12a on the surface of the mold roller is buried and the transparent substrate film is in contact with the exposed surface of the buried ionizing radiation-curable resin composition. However, when the transparent substrate 2a is not used, a sufficient amount of the ionizing radiation-curable resin composition may be applied so that the ionizing radiation-curable resin composition forms a continuous film on the mold surface.

In the illustrated example, the ionizing radiation-curable resin composition is applied to the mold roller 12. This is preferable. However, if the inclusion of bubbles during lamination can be prevented, the ionizing radiation-curing resin After applying the resin composition to the transparent substrate 2a side, the resin composition may be brought into contact with the mold roller 12, or the ionizing radiation-curable resin composition may be supplied to a position where the transparent substrate 2a contacts the mold roller 12. You may.

After applying the ionizing radiation-curable resin composition on the surface of the mold roller 12, doctor ring may be applied if necessary to regulate the amount of application. In the above, as the ionizing radiation, ultraviolet rays or electron beams are usually used, but other than these may be used. Further, the irradiation position is not limited to the upper one position, and irradiation may be performed by installing a desired number of ionizing radiation irradiation devices at an arbitrary position immediately after the application and before passing through the nip roller 11b. . If a sufficient space cannot be secured around the mold roller 12, an ionizing radiation irradiating device may be further installed at a position after the nip roller 11b has exited to perform irradiation.

The irradiation of ionizing radiation cures the ionizing radiation-curable resin composition 17 and produces an adhesive force with the transparent substrate film 1. A transparent layer made of the cured ionizing radiation-curable resin composition is laminated on the substrate 2a, and fine irregularities 3a reflecting the shape of the fine irregularities on the mold surface are formed on the surface of the transparent layer.

Incidentally, in order to obtain a transparent layer having no transparent substrate 2a and fine irregularities directly formed on the transparent layer, there is a method in which lamination of the transparent substrate 2a is omitted. The surface on the side to which the ionizing radiation-curable resin composition is applied is given releasability, and the transparent substrate is separated from the mold surface and the transparent substrate 2a is separated at the same time, or only the transparent substrate 2a is first removed. By peeling the transparent layer after the peeling, or by peeling the transparent substrate 2a after the peeling together, it is possible to obtain a transparent layer without the transparent substrate 2a, in which fine irregularities are directly formed on the transparent layer. . However, it is preferable to use the transparent substrate 2a during the process because the thickness of the transparent layer can be easily regulated and the influence of dust in the air can be avoided.

The antireflection material of the present invention exhibits a sufficient effect even when the fine irregularities 3a are exposed on the surface. However, in order to prevent scratches and contamination due to inadvertent contact, the antireflection material is more effective than the transparent layer. It is preferable that a layer made of a resin composition having a low refractive index is laminated on the fine unevenness 3a.

When the layer 4 to be laminated on the fine irregularities 3a is formed of a fluorine resin or silicone resin material,
Since the refractive index of light is 1.3 to 1.4 in all cases, the general refractive index of a transparent layer made of a cured product of an ionizing radiation-curable resin composition (a cured product of an acrylate resin composition. , And the refractive index of light is 1.5 or more.) Since these materials have a contact angle of 100 ° or more with water, they also have antifouling properties and are therefore preferable. When the use of the above-mentioned fluorine-based resin or silicone-based resin, etc., makes it unnecessary to provide a special function to the surface,
A thermoplastic resin other than the fluororesin / silicone resin selected in consideration of adhesion to the lower transparent layer 3 may be used instead.

These materials may be formed by either a dry process such as vapor deposition or a wet process such as ordinary coating. Alternatively, a method in which the transparent layer is applied in advance to a mold surface for providing fine irregularities, and an ionizing radiation-curable resin composition is applied thereon, and a method of laminating the transparent layer may be employed. Or, when the above-mentioned fluorine-based resin or silicone-based resin is mixed with an ionizing radiation-curable resin composition for forming a transparent layer to form a transparent layer,
The fluorinated resin or silicone resin may be bleed out.

The hard coat layer 5 is applied by a known coating method using the ionizing radiation-curable resin composition used for forming the uneven surface 3 having the fine unevenness 3a, and after the application, the ultraviolet light is applied. And irradiating the film to crosslink and cure the coating film. If necessary, an ultraviolet absorber may be added to the hard coat layer 5 for the purpose of preventing deterioration due to ultraviolet rays as long as the start of photopolymerization is not hindered. The thickness of the hard coat layer 5 is preferably 0.5 to 30 μm, more preferably 2 to 15 μm. If the thickness of the hard coat layer 5 is too thin, the resulting surface has insufficient durability such as hardness and stain resistance, and
Too thick will reduce overall flexibility, and
For example, it takes a long time to cure, leading to a decrease in production efficiency.

The antireflection layer 6 includes, for example, (1) a high refractive index layer and a low refractive index layer sequentially laminated, (2) a high refractive index layer, a low refractive index layer, a high refractive index layer, and A low refractive index layer is sequentially laminated, or (3) a medium refractive index layer, a high refractive index layer, and a low refractive index layer are sequentially laminated, but other materials may be used. .

The high refractive index layer in (1) and (2) and the medium refractive index layer in (3) are, for example, Zn
O, TiO ₂ , CeO ₂ , Sb ₂ O ₅ , SnO ₂ , indium tin oxide, antimony-doped indium tin oxide, In
_A thin film made of a material selected from the group consisting of ₂ O ₃ , Y ₂ O ₃ , La ₂ O ₃ , Al ₂ O ₃ , HfO ₂ , and ZrO ₂ , or a resin film in which ultrafine particles made of these materials are dispersed Can be configured.

The low refractive index layer in (1), (2) and (3) is, for example, a thin film made of SiO ₂ ,
It can be composed of an O ₂ gel film or a cured film of a fluorine-containing or fluorine- and silicon-containing ultraviolet-curable resin composition.

The high refractive index layer in the above (3) is made of, for example, Fe, Ni, Cr, Ti, Hf, Zn, Zr, M
It can be composed of a metal thin film made of a metal selected from the group consisting of o and Ta, or a resin film in which ultrafine particles made of these metals are dispersed.

Each of the above-mentioned layers is formed by vapor deposition or sputtering in the case of a thin film of metal or the like.
They can be formed by coating with a solvent solution or the like. The antireflection layer 6 is preferably laminated on the hard coat layer 5, but the antireflection function can be exhibited without the hard coat layer 5. However, in order to impart physical strength to the antireflection layer 6,
It is preferable to laminate the antireflection layer 6 on the hard coat layer 5.

The window plate 1 of the present invention, which can be a single-layer or a multi-layer laminate of the above-described various structures, is punched into a required shape and formed into a predetermined shape. It can be used for a display cover of a portable device having the same.

FIG. 8 is a view showing a state in which the display unit of a portable telephone having a display unit is covered with a window plate 1. The window plate 1 has a predetermined shape as shown in FIG. The cross-sectional shape in the direction indicated by the arrow has a shape as shown in FIG. 8 (c), and it is necessary to fit into the opening for fitting the window plate 1 of the outer case of the mobile phone. It is a planned one. Of course, the window plate 1 may be fixed to the portable telephone by other various methods.

[0081]

(Example 1) A photosensitive resin layer was laminated on a glass substrate, exposed in three directions by a laser interference exposure apparatus, and after the exposure, solvent development was carried out, and the photosensitive resin was cured. Then, a prototype was obtained in which a large number of fine irregularities having a height of 180 nm to 350 nm and a pitch of 100 nm to 350 nm were arranged in a lattice pattern. Using a mold in which the mold surface of the above-mentioned prototype was mounted on the inner surface, an acrylic resin was injected to obtain an acrylic resin plate having fine irregularities on one surface.

On the surface of the plate obtained above that does not have fine irregularities, a frame and characters of the size of the display portion are printed,
Further, a hard coat layer was formed on the entire surface including the printing surface using an acrylate-based ultraviolet curable resin. Subsequently, Ti is deposited on the hard coat layer by CVD sputtering.
O ₂ , SiO ₂ , and TO ₂ thin films were all
The layers were formed in this order with a thickness of m to form an antireflection layer.

As described above, fine irregularities are formed on one surface, and a hard coat layer, a TiO ₂ thin film, a SiO ₂ thin film are formed on the other surface.
And a transparent plate on which a TO ₂ thin film was formed in order, and the reflectance was measured with a spectrophotometer in a wavelength range of 400 nm to 700 nm, and was 0.1% to 1%.
Also, after confirming that the transparent plate has a predetermined size, the side having fine irregularities is formed on an opening formed in a size of the display unit in a case outside the liquid crystal display unit of the mobile phone. When it was fitted so as to be on the inner side, the brightness at the time of displaying on the liquid crystal display of the telephone was greatly improved as compared with the case where the inner side did not have fine irregularities. Further, in this case, since the irregularity of the part is directed to the inner surface, there is no damage of the irregularity due to abrasion, and there is no reduction in brightness of the display part due to the abrasion.

[0084]

According to the first aspect of the present invention, it is possible to prevent the reflection of incident light from at least the uneven surface on which the fine unevenness is formed. An anti-reflective window plate can be provided. According to the invention of claim 2, anti-reflection property for a display unit cover of a portable device having a display unit, which can prevent reflection of incident light from one side of the uneven surface on which fine unevenness is formed. Window boards can be provided. According to the third aspect of the present invention, it is possible to prevent reflection of incident light from the uneven surface on which fine unevenness is formed on both sides, and the antireflection property for the display unit cover of a portable device having a display unit. Window boards can be provided. According to the invention of claim 4, according to the invention of claims 1 to 3, in addition to the effect of any one of claims 1 to 3, the design layer is laminated, so that the design is imparted, An anti-reflective window for a display unit cover of a portable device having a display unit, which can exhibit a function of shielding the periphery of the display unit, or displaying a name of the device or an item name of the content displayed on the display. Boards can be provided. According to the fifth aspect of the present invention, in addition to the effects of any one of the first to fifth aspects of the present invention, at least a physical property or a chemical property is imparted to or improved on the side where the hard coat layer is laminated. It is possible to provide an anti-reflection window plate for a display unit cover of a portable device having a display unit, the display unit cover being capable of being operated. According to the invention of claim 6, claim 1
In addition to the effects of any one of claims 5 to 5, a portable device having a display portion capable of imparting or improving physical properties and chemical properties on the surface on which the hard coat layer is laminated is provided. It is possible to provide an antireflection window plate for a display unit cover of a simple device. According to the seventh aspect of the present invention, it is possible to provide a portable device having an antireflection window plate for a cover in a display unit, which exhibits the effects of any one of the first to sixth aspects of the invention.

[Brief description of the drawings]

FIG. 1 is a view showing a basic shape of a window plate.

FIG. 2 is a view showing a window plate with a pattern layer.

FIG. 3 is a view showing a window plate with a hard coat layer.

FIG. 4 is a view showing an example in which an antireflection layer is provided on a hard coat layer.

FIG. 5 is a view showing various cross-sectional shapes of fine irregularities.

FIG. 6 is a diagram showing an arrangement of fine irregularities.

FIG. 7 is a diagram showing a method for producing fine irregularities.

FIG. 8 is a diagram showing an example applied to a mobile phone.

[Explanation of symbols]

 Reference Signs List 1 window plate 2 transparent plate 3 uneven surface (3a; fine unevenness) 4 pattern layer 5 hard coat layer 6 antireflection layer 11 nip roller 12 type roller 13 die head 14 liquid reservoir 15 slit 16 pipe 17 ionizing radiation curable resin composition 18 ionization Radiation irradiation device 21 Mobile phone

Continued on front page F-term (reference) 2H091 FA31X FA37X FC10 FC23 FC25 FC29 GA16 LA12 2K009 AA02 AA12 AA15 BB02 BB14 BB24 BB25 BB28 CC03 CC24 CC42 DD04 DD05 DD15 4F100 AA20D AA21C AK25A AK25BAR00A00 BA00 AR00A00 BA00 AR00D HB31B JB14B JK12B JM02C JM02D JN01A JN06C JN06D JN30

Claims (7)

[Claims] 1. A reflection for a display unit cover of a portable device having a display unit, characterized in that at least one side of a transparent plate has an uneven surface on which innumerable fine unevenness with a pitch equal to or less than the wavelength of light is formed. Preventive window board. 2. The display of a portable device having a display unit according to claim 1, wherein one side of the transparent plate has an uneven surface on which innumerable fine unevenness is formed at a pitch equal to or less than the wavelength of light. Anti-reflective window plate for head cover. 3. The display of a portable device having a display unit according to claim 1, wherein the transparent plate has, on both sides thereof, an uneven surface on which innumerable fine unevennesses having a pitch equal to or less than the wavelength of light are formed. Anti-reflective window plate for head cover. 4. A pattern layer is laminated on one side or both sides of the transparent plate.
An antireflection window plate for a display unit cover of a portable device having the display unit according to any one of the above. 5. A hard coat layer is laminated on one or both sides of the transparent plate.
An antireflective window plate for a display unit cover of a portable device having the display unit according to claim 4. 6. An anti-reflection layer comprising a plurality of thin-film layers having different refractive indices is sequentially laminated on one or both sides of the transparent plate.
An antireflection window plate for a display unit cover of a portable device having the display unit according to any one of the above. 7. A portable device having a display unit, comprising the antireflection window plate according to claim 1 on an observation side on the display unit.