North American Philips Corporation

U.S. Philips Corporation

Philips Electronics North America Corporation

Philips Electronics N.a. Corporation

Robert L Donofrio

Andre A Van Der Voort

A method for improving the adherence of a phosphor screen to the face panel of a color cathode ray tube involves placing a UV reflective filter on the inside of the face panel prior to photolithographic forming of the screen, in order to reflect transmitted UV light back onto those areas form which the light emerged, thereby effectively increasing the exposure dosage of those areas.

Method for producing phosphor screens, and color cathode ray tubes

Adherence of the phosphor screen to the face panel of a color cathode ray tube is improved by placing a UV-reflective filter on the inside of the face panel prior to photolithographic forming of the screen, in order to reflect transmitted UV light back onto those areas from which the light emerged, thereby effectively increasing the exposure dosage of those areas.

The bulls-eye effect produced in the projected image by projection television cathode ray display tubes with convexly curved faceplates and multi-layer interference filters is compensated by using darkened or tinted glass. Since the faceplate glass is thicker in the center, more attenuation of the light output occurs there than at the edges of the display window where the glass is thinner, resulting in improved luminance uniformity of the display.

Monochrome CRT having curved display window with reduced transmission

The brightness of a color CRT with a pigmented phosphor screen is improved by providing a composite layered screen in which a first layer of the composite layer is a relatively thin, heavily pigmented layer and a second is non-pigmented.

Phosphor search including a non-pigmented phosphor and RGB phosphor

Output and/or perceived persistence of visible light from a cathode ray tube is improved by incorporating a UV-excitable phosphor into the screen, and by placing a UV-reflective filter on the inside of the display panel prior to formation of the phosphor screen, so that UV light emitted from the screen upon excitation by the tube's electron beam(s) is reflected back onto the screen to excite the further emission of visible light.

Cathode ray tube with UV-reflective filter and UV-excitable phosphor

A color reference CRT of the type employing a screen of a pattern of individual phosphor elements of different color components, is produced by adjusting the screen weights of the different color components to achieve the desired reference color when the screen is scanned by an electron beam of predetermined beam current and anode potential.

Color reference CRT and method of making

The bulls-eye effect produced by projection television cathode ray display tubes with convexly curved faceplates and multi-layer interference filters is compensated by increasing the optical absorption of one of the filter layers having a decreasing center-to-edge thickness gradient. Since the layer is thicker in the center, more attenuation of the light output occurs there than at the edges of the display window, resulting in improved luminance uniformity of the display.

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Ann Arbor, MI, United States of America

Robert L Donofrio