Colour selection mask and frame for CRT - has volume of thin walled mask related to volume of thick walled frame by empirical formula for good thermal characteristics

摘要

The colour selection masking system for use in a colour television CRT consists of a thin walled colour selection mask (1) which is attached at its circumference to a frame (2) made from a thick walled metal. The thermal properties of the mask are considerably improved during the period immediately after switching on the set. The wall thickness of the frame is at least equal to and not greater than fifteen times the wall thickness of the colour selection mask. The mask frame is designed to empirical formulae relating the volume of the frame material to that of the mask material. Parameters appearing in the formulae are: specific heat, density, mean number of electrons impinging on the frame and the mask surface areas and the thickness of both the frame and the mask in each case.