Colour television tube screen - for shadow mask tubes - with improved colour dot definition by use of diffusion resistant zon

摘要

Diffusion resistant zones, corresponding in size and shape to the holes in the shadow mask, are formed on the rear face of the front plate and within them limited protected zones are formed by diffusion, e.g. of Ag to replace e.g. Na, into the embedment material from an ion exchange cpd. applied over the zones between the original diffusion resistant areas heated to 400-600 degrees C for 1-3 hrs after which the excess is removed together with the diffusion resistant material. The individual colour dot triolets are then deposited on the central protected islands so formed. The resultant definition is improved.