Radiation imagery chemistry: process – composition – or product th – Imaging affecting physical property of radiation sensitive... – Radiation sensitive composition or product or process of making
Reexamination Certificate
1999-03-10
2001-07-03
Le, Hoa Van (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Imaging affecting physical property of radiation sensitive...
Radiation sensitive composition or product or process of making
C430S273100
Reexamination Certificate
active
06255031
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an infrared absorbing film, which absorbs near-infrared rays emitted by image output devices such as plasma displays, lighting appliances or the like so as to prevent the penetration of the rays through the film, thereby preventing malfunction of remote-control infrared communication ports which use rays falling within an infrared range for communication and even preventing malfunction of appliances to be controlled by those remote-control devices. More precisely, the invention relates to a multi-layered film or a panel of a multi-layered sheet that includes an absorbing layer which exhibits a near-infrared absorbing effect and an electromagnetic radiation shielding effect and which is combined with a transparent conductor. The present invention further relates to a near-infrared cut-off filter to be used, for example, for light-receiving sensitivity correction or color tone correction in photodiodes or solid image sensor (CCD) cameras used in light-receiving devices or image pickup devices in optical appliances, and also to a film or panel to be used for detecting forged cash cards and ID cards. The multi-layered sheet referred to herein is prepared by laminating functional films, including the film according to the present invention, on a substrate which has a shape-retaining function and is transparent.
DESCRIPTION OF RELATED ART
Conventional near-infrared-absorbing panels include glass filters having a metal deposit film formed thereon, and metal ion-containing phosphate glass filters. However, because of the phenomenon of interference, the glass filters having the metal deposit film are problematic in that they are negatively influenced by reflected light and their infrared-absorbing capabilities often do not correspond to luminous quantities. In addition, the manufacturing costs of such glass filters containing the metal deposit film are high. On the other hand, the metal ion-containing phosphate glass filters are also problematic in that the filters absorb moisture and they require a complicated manufacturing process. Moreover, the conventional glass filters are further problematic in that they are heavy and are easily cracked, and they are difficult to handle.
In order to solve these problems, various plastic materials having absorption characteristics within the infrared range have been proposed for producing plastic filters. For example, as described in Japanese Patent Application Laid-Open (JP-A) Hei-6-214113, panels are produced by dissolving a metal phthalocyanine compound in a monomer of methyl methacrylate followed by polymerizing the monomer. Also known are near-infrared-absorbing panels which are produced by kneading a phthalocyanine compound or an anthraquinone or cyanine compound in a resin melt followed by sheeting the resulting mixture through extrusion.
However, the panel production includes the steps of high-temperature melt extrusion and polymerization, and therefore can not be used with near-infrared-absorbing materials which are thermally unstable or with materials which are decomposed or deteriorated through chemical reaction. Accordingly, the near-infrared-absorbing characteristics of conventional panels produced are not satisfactory.
In addition, when panels are used in displays, etc., the near-infrared-absorbing characteristics and the color tone characteristics of the panels are important. To control the color tone of panels, in general, a plurality of different dyes must be mixed. However, when mixed with other dyes, some dyes having near-infrared-absorbing characteristics may change their characteristics, or may even change their near-infrared-absorbing capabilities through chemical reaction or dielectric interaction with the dyes mixed therewith.
BRIEF DESCRIPTION OF THE INVENTION
To overcome the drawbacks and problems of the prior art described above, the preferred embodiments of the present invention provide a multi-layered, near-infrared-absorbing film or panel, which includes an absorbing layer of a near-infrared-absorbing dye dispersed in a transparent polymer material. In addition, a near-infrared-absorbing panel of such a multi-layered film or sheet according to preferred embodiments of the present invention which solves the problem with conventional devices described above is produced by a specific method of casting or coating a uniform mixture including a near-infrared-absorbing dye and a polymer resin. In this method, the dye and the polymer resin material may be selectively combined. Accordingly, the preferred embodiments of the present invention provide a film having a high near-infrared absorbance and a high visible-ray transmittance, and also a panel of a multi-layered sheet including such a novel film.
Another preferred embodiment of the present invention provides a near-infrared-absorbing, single-layered or multi-layered film which includes an absorbing layer of a near-infrared-absorbing dye dispersed in a transparent polymer resin, and also a multi-layered sheet panel including such a novel film. When mixed with different dyes, some dyes change their characteristics, or some others chemically react with them or dielectrically interact with them, or still some others lose their thermal stability. Therefore, in preferred embodiments of the present invention, individual dyes are separately sheeted into different films using suitable methods, depending on their characteristics, and a plurality of the resulting films are laminated to define a multi-layered film or sheet in such a manner that the multi-layered film or sheet exhibits desired color tones in the near-infrared-absorbing range and the visible-ray range.
REFERENCES:
patent: 5530086 (1996-06-01), Fuji et al.
patent: 5856060 (1999-01-01), Kawamura et al.
patent: 6-214113 (1994-08-01), None
patent: 6-256541 (1994-09-01), None
patent: 7-178861 (1995-07-01), None
patent: 6-317755 (1996-11-01), None
patent: 6-355880 (1996-12-01), None
patent: 7-236103 (1997-09-01), None
patent: 7-297697 (1997-10-01), None
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patent: 8-26965 (1998-02-01), None
Igarashi Kouei
Indo Takashi
Koike Masahiro
Sakurai Kazuo
Suzuki Yasuko
Gilmore Barbara
Hogan & Hartson LLP
Kanebo Ltd.
Le Hoa Van
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