GB1259704A - An electron gun structure and an apparatus for assembling the same - Google Patents

Abstract

1,259,704. Electron guns. TOKYO SHIBAUBA ELECTRIC CO. Ltd. 24 April, 1969 [25 April, 1968; 5 July, 1968; 30 Sept., 1968], No. 21022/69. Heading H1D. In a multiple electron gun, e.g. a triple gun for a shadow mask colour television tube, each gun comprises a cathode followed by five grid electrodes and the fourth grid 15a has a larger diameter than the ends of the third and fifth grids and is operated at 5 to 20% of the final anode voltage which is applied to the third and fifth grids. The fifth grid 16a may have an end portion of reduced diameter which extends into the fourth grid, as shown in Fig. 7, or may be generally cylindrical with a flared outer end, as shown in Fig. 14. Assembling electrodes.-In one arrangement, Fig. 7, the electrodes of a gun are mounted on a support rod 23 with intervening spacers 32-34 and clamped in a jig 27. Each spacer between the fourth grid 15a and its adjacent grids comprises two generally spanner-shaped members 32 and 32<SP>1</SP> (Figs. 10-17, not shown) each provided with a U-shaped slot the axes of which are displaced to define a circular aperture in which the projecting end of grid 14a or 16a is located, the members 32 being provided with cylindrical projections adapted to fit inside the grid 15a. The tapered end 24 of the rod 23 is pressed against a groove in a supporting member 21 by resilient means 37; two other similar assemblies (not shown) are accommodated in other grooves in member 21 so that the three guns are arranged in the required converging alignment whilst support tabs fixed to the electrodes are secured to glass support rods. In another arrangement, Fig. 14, the support rod 69 on which the electrodes are assembled has a tapered end which fits into a tapered aperture 61 in a base 60. Lateral support members 63 are pivoted to the base and are provided with pins 64 adapted to be received in a top plate 65; a spring 78 bearing on the top plate 65 applies pressure to the assembly. In this arrangement the fourth grid 15a is supported on a stepped portion of a cylindrical spacer 71; this is mounted in turn on a ring spacer 70 which may be supported by the rod 69, as shown, or may be supported directly by the base 60, preferably in a recess in the base (Fig. 17, not shown). Two slits are provided in the spacer 71 to allow passage of the support tabs (not shown) for the electrode 16a.