Stock material or miscellaneous articles – Composite – Of quartz or glass
Reexamination Certificate
2000-04-03
2004-02-03
Jones, Deborah (Department: 1775)
Stock material or miscellaneous articles
Composite
Of quartz or glass
C428S432000, C428S433000, C428S697000, C428S699000, C428S701000, C428S702000, C359S359000, C359S580000, C359S586000
Reexamination Certificate
active
06686049
ABSTRACT:
TECHNICAL FIELD
The present invention relates to anti-reflection colored film-coated glass products, and particularly to anti-reflection colored film-coated glass panels that reduce visible light reflection and adjust transmitted color tones, and to optical filters that employ them.
BACKGROUND ART
Anti-reflection films have been conventionally used in optical parts of cameras and eyeglasses, and in indicators for OA electronic devices such as indicator panels and displays. Such anti-reflection films must have low reflective properties and high transmittivity in order to increase visibility or enhance the original optical properties.
A wide variety of colored films comprising inorganic oxides doped with fine noble metal powders have been known. For example, it has been disclosed that doping silica-titania films with fine gold powder provides color film-attached glass, and that colors such as red, reddish-purple, blue, blue-green and green can be obtained depending on the amount of silica and titania in the films. [For example, (a) H. Kozuka, Control of optical properties of gel-derived oxide coating films containing fine metal particles, J. Sol-Gel Sci. Tech., 2, 741-744(1994), and Japanese Laid-open Patent Publication No. H6-191896].
There have also been disclosed glass products coated with colored films to a thickness of 80-140 nm, having visible light reflectivity (light irradiation from the film side) of 5-7% and colored red/reddish purple to green/gray to gray, by doping silica films or silica-titania films with fine gold powder ((b) Japanese Laid-open Patent Publication No. H9-295834).
On the other hand, plasma display panels (PDPs) have been developed in recent years for large-sized wall-mounted television sets, and efforts are being devoted toward development of their wider use. The front side of a PDP is commonly provided with an optical filter having a multilayer anti-reflection layer to prevent reflection of external light and an electromagnetic wave blocking layer, and this complements the color emitted by the PDP.
For example, there are known products wherein an anti-reflection film (made by overlapping vapor deposited films of materials with different refractive indexes) is bonded to one surface of a colored transparent substrate (for production of acrylic resins or polycarbonate resins, a mixture of a pigment that absorbs the excess red components emitted by the PDP into the resin prevents the purplish appearance of emitted color tones that are originally blue colors) with a transparent adhesive, while (1) a film that blocks electromagnetic waves and a line spectrum in the near infrared region (made, for example, by sputtering the surface of a PET film with silver-inorganic oxide fine particles) and (2) an interference pattern-preventing film (prepared, for example, by forming fine irregularities on the outside surface of a transparent film so as to prevent adhesion to the PDP even when contacted with the PDP) are bonded with a transparent adhesive in that order onto the other surface of the transparent substrate (for example, (c) Japanese Laid-open Patent Publication No. H9-306366).
The prior art colored films of (a) that are doped with fine noble metal powders allow a certain degree of freedom in control of color tones, but offer virtually no anti-reflection performance. Those of (b) with reflectivity referred to above have had a problem in that they exhibit little difference from untreated transparent substrates in terms of their visible light ray reflectivity values, and have notable reductions in transmittance.
For optical filters used in PDPs, since the films of (c) have pigments mixed in resin sheets and anti-reflection films are pasted onto their surfaces, their higher production cost has been a problem.
It is an object of the present invention to solve these issues associated with the prior art by providing anti-reflection colored film-coated glass products which have excellent anti-reflection performance for visible light, allow freedom in control of the color tones of transmitted light, and which have high visible light transmittance, as well as the PDP optical filters that employ them.
DISCLOSURE OF THE INVENTION
The present invention provides an anti-reflection colored film prepared by forming an anti-reflection film comprising two layers with different refractive indexes on a transparent glass substrate, while using at least one of the layers as a selective absorption film to provide a coloring function.
In other words, the present invention relates to an anti-reflection colored film-coated glass product prepared Iby forming on a transparent glass substrate with a refractive index of 1.47-1.53, a high refractive index film with a refractive index of 1.59-2.30 and a film thickness of 80-140 nm and containing 0-85% silicon oxides, 10-95% titanium oxides and 5-30% fine gold particles in terms of weight percentage, and by forming on the high refractive index film, a low refractive index film with a refractive index which is a value in the range of 1.35-1.58 and at least 0.20 smaller than the refractive index of the high refractive index film, having a film thickness of 70-99 nm and containing 90-100% silicon oxides in terms of weight percentage.
The invention further relates to an anti-reflection colored film-coated glass product prepared by forming on the aforementioned transparent glass substrate, a high refractive index film with a refractive index which is a value in the range of 1.59-2.30 and a film thickness of 80-140 nm and containing 0-89% silicon oxides and 11-100% titanium oxides in terms of weight percentage, and by forming on the high refractive index film, a low refractive index film with a refractive index of 1.35-1.58 and at least 0.20 smaller than the refractive index of the aforementioned high refractive index film, having a film thickness of 70-99 nm and containing 70-95% silicon oxides and 4-30% fine gold powder in terms of weight percentage.
Each of the components of the high refractive index film of the invention will now be explained.
The silicon oxides are not essential components but are effective for adjusting the refractive index of the film, and when present in a low content they increase the refractive index of the colored film, producing a bluish green color in the film. Conversely, when present in a high content the refractive index of the colored film is lowered, producing a reddish purple color in the film.
If the silicon oxide content is too high, the substrate will undergo deformation due to a large contraction of the film during heating of the film, and therefore the silicon oxide content is 0-85 wt %, and preferably 0-70 wt %, in terms of SiO
2
.
The titanium oxides are necessary for formation of the film and to increase the refractive index of the colored film, and when they are present in a low content they lower the refractive index of the colored film, producing a reddish purple color in the film. When the titanium oxides are present in a high content they increase the refractive index of the colored film, producing a bluish green color in the film.
If the titanium oxide content is very low the film formability and transparency are reduced, and therefore the content is 10-95wt %, preferably 20-90wt % and more preferably 25-85 wt % in terms of TiO
2
.
The gold, in the form of fine coloring particles, is necessary to provide color to the high refractive index film, and if its content is very low the coloring obtained will be insufficient, whereas if it is too high the durability of the film may be decreased and loses excess fine gold particles out of the film and preventing their color contribution. The fine gold particle content is therefore 5-30 wt %, preferably 5-25 wt %, and more preferably 8-23 wt %.
If the thickness d, (physical film thickness) of the high refractive index film is too small the anti-reflection effect will be lower, and the coloring effect will be reduced. Conversely, if it is too thick, the anti-reflection effect will be lower, and cracks may be produced thus lowering the film stren
Nakamura Koichiro
Tsujino Toshifumi
Blackwell-Rudasill G. A.
Conlin David G.
Edwards & Angell LLP
Jones Deborah
Konieczny J. Mark
LandOfFree
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