GB1309696A - Shadow mask support means for a colour television image tube - Google Patents

Abstract

1309696 Colour television display tubes MATSUSHITA ELECTRONICS CORP 16 March 1970 [19 March 1969 (2)] 12578/70 Heading H1D A shadow mask support mechanism for a colour TV tube includes three or four mask supporters at least one of the supporters comprising a bi-metal member 17 secured to the frame 2, its free end connected to a leaf spring 8 the other end of which extends towards a pin provided on the tube side wall. The thermal deflection at the metal platen-spring connection is such that the expansion at the pin side is smaller than on the other side this preventing local twisting of the spring and non-uniform movement of the mask towards the screen. Uniform movement toward the screen compensates for colour purity errors due to thermal expansion. The bimetal piece 17 welding line L may intersect the welding line l in the range five to fourty degrees, preferably about fifteen degrees. Two bimetal parts (27), (37), (Fig. 5, not shown), may be used in parallel, of respectively different expansion coefficients by including different materials for each other, or may be of different thicknesses or shapes. Also the part (37) on the pin side may be replaced by a single layer metal plate. A lower expansion U-shaped metal plate (47a), (Fig. 6, not shown), may be combined with a higher expansion plate attached to the leg remote from the pin or a bimetal plate (57), (Fig. 7, not shown), may include a further metal piece (57c) welded at the side near the pin to mechanically reduce the expansion.