Browse Prior Art Database

Anti-Reflection Treatment for Cathode Ray Tubes

IP.com Disclosure Number: IPCOM000049058D
Original Publication Date: 1982-May-01
Included in the Prior Art Database: 2005-Feb-09
Document File: 2 page(s) / 21K

Publishing Venue

IBM

Related People

Pascual, R: AUTHOR

Abstract

Acceptable diffused reflections from the inner surface of a monochrome cathode ray tube (CRT) are achieved by roughening the surface. Color tubes currently need smoother surfaces for subsequent processes, thus aggravating reflections.

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Anti-Reflection Treatment for Cathode Ray Tubes

Acceptable diffused reflections from the inner surface of a monochrome cathode ray tube (CRT) are achieved by roughening the surface. Color tubes currently need smoother surfaces for subsequent processes, thus aggravating reflections.

A layer of transparent medium, such as glass, acting as a matrix containing particles of a different refractive index will produce multiple reflections when illuminated, acting as a volume scatterer. By coating the inner surface of the CRT with such a composite layer, a balance can be struck between the smoothness and roughness requirements.

If glass 1 is matched to the CRT glass refractive index, no reflection at the interface (A) will take place and light will be scattered by glass 2 particles. Thinner layers and fine particles should not unduly affect phosphor resolution. Glass 1 has a lower melting point than the CRT glass and glass 2. The particles of glass 2 are small compared to the thickness of glass layer 1 which will thus provide a smooth surface at B for subsequent processes.

By varying the thickness of the composite glass layer, particle size distribution and refractive indexes, various levels of reflection/ scattering/ resolution can be adjusted. The technique can also be used in the design of projection screens.

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