Zenith Electronics Corporation

Johann Steiner

Paul Strauss

Robert J Adler

James R Fendley

Charles J Prazak

Howard G Lange

John M Jarosz

Allan D Kautz

Richard J Duchek

A production system is disclosed for registering flat tension masks to screen bearing face panels in the manufacture of cathode ray tubes. Both the panel and mask are supported in modules with identical registration features at loading stations and alternately conveyed to an assembly station with a top mounted laser welder for welding the mask to panel rails. A lift assembly up loads the modules into the assembly station where they are registered with the same registration elements. Screen location on the panel is interrogated by panel module associated cameras that view spaced fiducial marks on the panel previously located with respect to the screen. Mask interrogation is also accomplished by a camera array. Early screen interrogation enables the mask to be preliminarily positioned very close to final positioning.

System for registering and assembling tension masks and CRT faceplates

An apparatus and method for differentially stretching a flat tension mask to register apertures in the mask with an undedicated screen on a CRT faceplate. Stretching is accomplished biaxially on the mask with a plurality of separate clamping elements along all four sides of the mask. Various methods and means are disclosed for applying a fixed ratio of forces to the clamps to maintain strain in the mask substantially uniform across the entire mask, such as a 'wiffle tree' linkage and selected spring rate springs. Growth of the mask during stretching is accommodated by allowing the clamps to move laterally or perpendicular to the stretching forces. Fragile slit aperture masks are stretched with clamps having tangential component stretching forces. Individual and/or groups of clamps can be controlled independently of others to correct for localized mask or screen defects. The clamps move in unison toward the mask to a clamp engagement position where they are precisely aligned in a starting position. With the mask precisely located and held, the clamps are engaged. The clamps and mask are then released by their aligning devices and stretching begins.

Method and apparatus for stretching interchangeable tension masks in

Method and apparatus are disclosed for tensioning uniform foil shadow masks by clamping the edges of a mask and moving the clamps through a preselected fixed displacement, thereby obviating the need for extensive controls on the tensioning process.

Mechanically indexed mask stretching apparatus

Process and apparatus are disclosed for use in the manufacture of a color cathode ray tube having a shadow mask with a central pattern of apertures mounted in tension on a transparent flat front panel. The mask aperture pattern is registered with a cathodoluminescent screen pattern of corresponding geometry and position on an inner surface of the panel. The shadow masks and front panels are respectively interchangeable. In a preferred arrangement, signals are developed which are indicative of the positions of a mechanically stretched mask aperture pattern and an associated front panel screen pattern relative to a reference or to each other. Responsive to such signals, there is effected a relative positioning of the mask and screen until registration between the patterns is achieved.

Method and apparatus for making flat tension mask color cathode ray tubes

A method of manufacturing CRT tubes with binary coded faceplates including dispensing a frit paste on the faceplate in the form of a bar code. The frit is devitrified as part of conventional faceplate processing either during normalizing or during devitrification of the mask rail frit without any additional steps. In one embodiment the frit is dispensed through a single dispensing nozzle and the nozzle is moved relative to the faceplate in x and y coordinates to form a single undulating line. In another embodiment, frit is selectively dispensed through a plurality of nozzles for each character pair to form either narrow bars or wide bars.

Method of manufacturing cathode ray tubes with binary coded faceplates

A method is disclosed for use in the manufacture of a color cathode ray tube having a foil tension mask with a central pattern of apertures. A transparent flat front panel has a cathodoluminescent screen pattern on its inner surface. A plurality of mask support means, located on opposed sides of the screen pattern, have respective mask-receiving surfaces for receiving a shadow mask in tension. Q-height error data is developed according to the invention, and the aperture pattern of the mask in expanded and positioned in response to the error data to compensate for errors in Q-height to bring the mask apertures into registry with the screen pattern. Apparatus for measuring Q-height is also disclosed.

Process and apparatus are disclosed for use in the manufacture of a color cathode ray tube having a shadow mask with a central pattern of apertures mounted in tension on a transparent flat front panel. The mask aperture pattern is registered with a catholdoluminescent screen pattern of corresponding geometry and position on an inner surface of the panel. The shadow masks and front panels are respectively interchangeable. Signals are developed which are indicative of the positions of a mechanically stretched mask aperture pattern and an associated front panel screen pattern relative to a reference or to each other. Responsive to such signals, there is effected a relative positioning of the mask and screen until registration between the patterns is achieved.

Shielding means are disclosed for use in the manufacture of a tension mask color cathode ray tube having a glass faceplate and a substantially rectangular mask support structure having outwardly tapered sides for deflecting a mask-trimming laser beam away from the glass. The shielding means according to the invention are detachably supported by the support structure, or by the faceplate, for bridging only the corner areas of the support structure where the glass is exposed. The shielding means have a configuration effective to intercept the laser beam and shield the glass from the destructive effects of the laser beam. A process for use of the shielding means in manufacture is also disclosed.

Shielding means and process for use in the manufacture of tension mask

An improved front assembly for a color cathode ray tube having a tension foil shadow mask is disclosed. The faceplate of the tube has on its inner surface a centrally disposed phosphor screen surrounded by a peripheral sealing area adapted to mate with a funnel. A shadow mask support structure is provided for securing a shadow mask in tension on the structure and spacing the shadow mask from the screen. The support structure includes an undulated strip defining a bottom sinuous edge for securing the support structure to the faceplate and a top sinuous edge for securing the shadow mask to the support structure. A cap may be provided for securement to the top sinuous edge of the undulated strip to provide a land for securing the shadow mask to the support structure.

Tension mask assembly for a color CRT

A process for pre-treating a metal foil shadow mask is disclosed for use in a cathode ray tube wherein the shadow mask is maintained under high tension within said cathode ray tube, and wherein the mask is subjected to predetermined relatively high temperatures during tube manufacture. The process according to the invention comprises pre-heating the shadow mask in a predetermined cycle of temperature and time effective to minimize subsequent permanent dimensional changes in the mask that occur when it is subjected to the predetermined relatively high temperatures, but ineffective to significantly reduce the tensile strength of the mask by annealing.

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Des Plaines, IL, United States of America

Johann Steiner