CRT panel glass and CRT, and their production methods
AssigneeAsahi Glass Company, Limited
InventorsNoritoshi Horie, Tsunehiko Sugawara, Toshikazu Ikezawa, Takuji Oyama, Junnosuke Mizukami, Eiji Shidoji
Life of this patent
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Abstract
A CRT panel glass and a CRT wherein a surface treating film is formed on an outer surface of a CRT panel so that overall transmittance distribution and reflectance distribution within an effective picture plane satisfy specific mathematical expressions, whereby, even with a flattened panel glass, brightness and contrast are uniform over the entire surface of the image display plane, and their production method.
Claims15
A method for producing a CRT panel glass or a CRT, which comprises disposing baffle plates between an outer surface of a CRT panel on which a film is formed and a sputter target, and forming a surface treating film on the outer surface of said panel by a sputtering method so that the value A defined by the following mathematical expression (1) is less than 1 within an effective picture plane on the outer surface of said panel:
- 2 A value = [LeftBracketingBar] 1 - Tgf ( min ) Tgf ( max ) 1 - Tg ( min ) Tg ( max ) [RightBracketingBar] ( 1 )
- In the above mathematical expression (1):
- Tg(min) and Tg(max) represent the minimum transmittance (%) and the maximum transmittance (%) of the CRT panel itself, respectively;
- and
- Tgf(max) and Tgf(min) represent the maximum transmittance (%) and the minimum transmittance (%) of an integrated body comprising the CRT panel and the surface treating film, respectively.
A CRT panel glass, which comprises a surface treating film comprising a light-absorbing film and a low refractive index film laminated on the light-absorbing film, formed on an image display plane of a substrate glass having a flat image display plane and having such a light transmittance distribution that the light transmittance Tg(0) of the panel itself at the center portion of the flat image display plane and the light transmittance Tg(E) of the panel itself at a diagonal line top end corresponding to a panel effective plane end at each panel size as defined in accordance with individual standards by Electronic Industries Association of Japan EIAJ-2134B, satisfy “Tg(0)≧Tg(E)”;
- which has such a light transmittance distribution that the overall light transmittance Tgf(0) including the surface treating film at the center portion of the image display plane and the overall light transmittance Tgf(E) including the surface treating film at the diagonal line top end corresponding to the panel effective plane end at each panel size as defined in accordance with individual standards by Electronic Industries Association of Japan EIAJ-2134B, satisfy “Tfg(E)/Tgf(0)≧90%”;
- and which has such a reflectance distribution that the reflectance Rf(0) against light from the low refractive index film panel side at the center portion of the image display plane and the reflectance Rf(E) against light from the low refractive index film side at the diagonal line top end corresponding to the panel effective plane end at each size as defined in accordance with individual standards by Electronic Industries Association of Japan EIAJ-2134B, satisfy “|Rf(0)−Rf(E)|≦0.5%”.
Dependencies are inferred from the claim text.