Optical: systems and elements – Having significant infrared or ultraviolet property – Multilayer filter or multilayer reflector
Reexamination Certificate
1999-12-07
2001-06-26
Henry, Jon (Department: 2872)
Optical: systems and elements
Having significant infrared or ultraviolet property
Multilayer filter or multilayer reflector
C359S582000, C359S585000
Reexamination Certificate
active
06252703
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a transparent laminate and a filter using the transparent laminate for use in a plasma display panel (hereinafter referred to as PDP). Particularly, it relates to a PDP filter disposed on the front surface of a PDP for simultaneously cutting electromagnetic waves and near-infrared rays theoretically generated from the PDP, and a PDP display unit and a PDP front plate provided with the filter stuck thereto.
The present application is based on Japanese Patent Application No. Hei. 10-346816, which is incorporated herein by reference.
2. Description of the Related Art
Transparent laminates each having a metal thin film layer put between transparent dielectric film layers have been discussed with the advance of thin-film-forming technology represented by a vacuum vapor deposition method or a sputtering method. These transparent laminates can utilize both electrically conducting characteristic and infrared reflection characteristic of the metal thin film layer and can provide a function of preventing reflection of visible light on a metal surface by means of the transparent dielectric film layers. For example, these transparent laminates are used in transparent heat-insulating materials for solar cells, green houses for agriculture, window materials for buildings, show-cases for food, and so on, because these transparent laminates transmit visible light rays and reflect heat rays. Further, these laminates are used suitably in electrodes for liquid-crystal displays, electrodes for field light-emitters, electromagnetic wave shielding films, antistatic films, and so on, because these laminates are transparent and exhibit high electrically conducting characteristic. The configurations of these transparent laminates are disclosed, for example, in Japanese Patent Publications No. Sho. 55-11804, Hei. 9-176837, Hei. 10-217380, Hei. 10-264287, and so on.
On the other hand, with respect to display technology, a plasma display panel (hereinafter referred to as PDP) has been developed as a large-screen display in compliance with the wishes of reduction of thickness and weight and increase of screen size.
The PDP generates electric discharge in a gas mainly containing a rare gas, especially neon, enclosed in the panel. Fluorescent substances of R, G and B applied on cells in the panel are made to emit light by vacuum ultraviolet rays generated by the electric discharge. In this light-emitting process, electromagnetic waves and near-infrared rays unnecessary for the operation of the PDP are emitted simultaneously. Particularly, electromagnetic waves not only cause malfunctions of peripheral devices but also have a bad influence on human bodies. Accordingly, it is necessary to cut the electromagnetic waves.
Further, the wave length of the near-infrared rays emitted is in a range of from 850 to 1200 nm. On the other hand, the light-receiving sensitivity of remote controllers for domestic electrification products, karaoke, audio and video appliances, and so on, is in a range of from 700 to 1300 nm. There arises a problem that near-infrared rays emitted from the PDP cause the malfunctions of the remote controllers. Accordingly, it is necessary to cut the intensive near-infrared rays theoretically generated from the PDP.
Therefore, a filter capable of simultaneously cutting electromagnetic waves and near-infrared rays generated from the PDP has been discussed. For example, a plate, or the like, formed by sticking or thermally fusion-bonding an acrylic sheet having metal mesh or etching mesh embedded therein to an acrylic sheet mixed with a dye type material for absorbing near-infrared rays has been heretofore used as the filter. The mesh type filter was easy to obtain a low surface resistance value. The mesh type filter, however, had a problem in image blurring due to a moire phenomenon generated between pixel pitch and electrically conductive mesh, durability of a near-infrared absorbing material, and so on. Further, the amount of the near-infrared absorbing material to be added needed to increase in order to improve the near-infrared cut factor. With the increase of the amount of the near-infrared absorbing material, however, the defects of lowering of the visible light transmission factor and occurrence of color-eye could not be avoided.
On the other hand, application of the aforementioned transparent laminate to a PDP filter has been discussed. In the existing circumstances, there is, however, no transparent laminate sufficiently satisfying various characteristics such s electromagnetic wave shielding characteristic, near-infrared cutting characteristic, visible light transmission characteristic, low reflection characteristic, low surface resistance, surface mar-proofness, and so on.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a transparent laminate especially suitably used as an optical basic member in a PDP filter, and a light and thin-type PDP filter which satisfies various characteristics such as electromagnetic wave shielding characteristic, near-infrared cutting characteristic, visible light transmission characteristic, visible light low reflection characteristic, low surface resistance, surface mar-proofness, and so on, required by the PDP filter and which is good in visual recognition characteristic. Another object of the present invention is to provide a PDP display unit and a PDP front plate provided with the PDP filter.
As a result of eager discussion in order to solve the above objects, the present inventors have attained the invention which is a transparent laminate comprising: a transparent substrate; and 4 to 5 units of high refractive index transparent films and silver type transparent electrical conductor films, each unit consisting of one high refractive index transparent film and one silver type transparent electrical conductor film, the 4 to 5 unit being laminated successively on a surface of the transparent substrate, so that one high refractive index transparent film is disposed as an outermost layer, each of the high refractive index transparent film being an optically transparent film having a refractive index of from 1.5 to 2.7, each of the silver type transparent electrical conductor film having a thickness in a range of from 5 to 20 nm, wherein the transparent laminate satisfies the conditions: {circumflex over (1)} a thickness of the silver type transparent electrical conductor film disposed in a first layer with reference to the transparent substrate is substantially equal to a thickness of the silver type transparent electrical conductor film in an outermost layer with reference to the transparent substrate; {circumflex over (2)} a thickness of the silver type transparent electrical conductor film in each of other layers is 3/2(1±0.2) times as large as the thickness of the silver type transparent electrical conductor film in the first layer; {circumflex over (3)} a thickness of the high refractive index transparent film in a first layer with reference to the transparent substrate is substantially equal to a thickness of the high refractive index transparent film in an outermost layer with reference to the transparent substrate and is 7/2(1±0.2) times as large as the thickness of the silver type transparent electrical conductor film in the first layer; and {circumflex over (4)} the thickness of the high refractive index transparent film in each of other layers is 7(1±0.2) times as large as the thickness of the silver type transparent electrical conductor film in the first layer.
Preferably, the high refractive index transparent film is a thin film made from one compound or two or more compounds selected from the group consisting of indium oxide, tin oxide, titanium dioxide, cerium oxide, zirconium oxide, zinc oxide, tantalum oxide, niobium pentoxide, and zinc sulfide. Further, preferably, the silver type transparent electrical conductor film is a thin film made from 90% or higher by weight of silver and one compound or two or more e
Hieda Yoshihiro
Miyauchi Kazuhiko
Nakamura Toshitaka
Sasa Kazuaki
Henry Jon
McGinn & Gibb PLLC
Nitto Denko Corporation
LandOfFree
Transparent laminate and filter for use for plasma display... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Transparent laminate and filter for use for plasma display..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Transparent laminate and filter for use for plasma display... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2510640