GB1201016A - Colour television picture tube - Google Patents

Abstract

1,201,016. Colour television tubes. PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd. 18 June, 1969 [21 June, 1968], No. 30849/69. Heading H1D. The colour selection electrode 1, Fig 1, of a colour television tube is supported from the tube face-plate by at least three flat bimetal springs 2, 3 and 4, each formed of two strips 16, 17, Fig. 4, of dissimilar metals welded side-by-side along the seam 19, as disclosed in Specification 1,192,725, to move the electrode towards the face-plate with rise of temperature, simultaneous movement of the electrode in its plane being prevented by choosing, for each spring, a length and effective expansion coefficient such that the component of expansion parallel to the side of the electrode is equal to the expansion of that part of the electrode lying between the centre of that side and the point of attachment of the spring, e.g. parts 7 and 8 for springs 2 and 3 of Fig. 1, for at least one spring the matching of expansions being achieved by laterally displacing the point of support 13 of the spring by the face-plate from the seam 19 of the spring, as shown in Fig. 4. By employing a support point situated a sufficient distance from the seam in a strip 17 having a very small expansion coefficient, a substantially zero expansion may be obtained, as is required for the spring 3 of Fig. 1, or an effective negative expansion by further increasing the distance from the seam, e.g. by using a point of support at C on the edge of the lug 18.