Colour TV CRT shadow mask prodn. - uses electron beam to bore apertures with defined cross section in shadow mask sheet

摘要

The process of manufacturing of shadow masks of colour television cathode-ray tubes provides apertures of defined spacing in the mask sheet. The apertures (12) have a well defined cross section and are formed in the mask sheet (1) by an electron beam. Preferably the electron beam is controlled by a programmeable device which controls the beam direction, focussing, and intensity. The beam boring velocity of 3000 apertures per sec. enables to produce a shadow mask with 500 000 apertures in approximately 2.7 min.