North American Philips Consumer Electronics Corp.

Gte Products Corporation

North American Philips Corporation

Robert L Bergamo

Judy A Nagel

Anthony V Gallaro

Thaddeus V Rychlewski

Gordon T Foreman

Siegbert M Wirth

A positive-working photoresist composition is described comprising a solution of polyvinyl alcohol, an inorganic ferric salt, ammonium trioxalatoferrate and a diol such as 1,4-butanediol. There is also described the addition of a finely divided black pigment to such a composition and the use of such a black pigmented composition for the formation of a light-absorbing matrix in a color CRT screen structure.

Positive-working photoresist composition and method for forming a

Phosphor characters to supply feedback information for an automatic convergence system are applied to the gun side of the shadow mask of a color cathode ray tube by a method of applying layers of a positive-working photoresist and phosphor, exposing the layers through a positive photomask, back exposing to clear the shadow mask apertures, developing to remove the exposed areas, and baking to remove the photoresist.

Photographic process for applying phosphor pattern to color CRT shadow

A method for forming patterned screens for cathode ray tubes wherein a multiplicity of viewing areas are spaced in accordance with and dimensionally smaller than openings of a mask member comprising the steps of coating the inner surface of a viewing panel with polyvinyl alcohol photosensitized with dichromate; exposing the viewing panel at a first positional location to radiant energy beamed through the mask openings; moving the viewing panel to a second positional location and exposing the viewing panel to radiant energy beamed through the mask openings; developing to remove the unexposed coating from the viewing panel; treating the exposed viewing panel with a dilute organic etching composition to erode the coating exposed to the radiant energy at one of the first and second positional locations; and washing the viewing panel to remove the etching composition and eroded coating leaving polymerized coating of a dimension smaller than the openings of the mask member.

Method for reducing pattern stripes in slotted mask screens for cathode

Growing community of inventors

Seneca Falls, NY, United States of America

Robert L Bergamo