| 摘要 |
1535064 Colour television tubes PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd 22 Oct 1976 [27 Oct 1975] 43946/76 Heading H1D The screen of a shadow-mask colour television tube is manufactured by (a) providing a conductive layer on the faceplate. (b) Providing an electron absorbing layer-which is preferably photovoltaic-on the conductive layer. (c) Scanning the faceplate with an electron beam through the shadow-mask to form a charge pattern on the electron absorbing layer. (d) Developing the charge pattern by spraying with positively charged phosphor particles. After development, remaining charge is removed by exposure to UV and steps (c) and (d) repeated with phosphor particles of a different colour, a black-matrix being formed by performing step (c) with each of the three colour guns, and developing with negatively charged particles of a light-absorbing pigment. A desired phosphor dot size, compared with the mask aperture size, and variation of dot size over the screen of the faceplate, can be achieved by the use of a suitable potential difference between the mask and the screen, which may be a function of the scanning beam instantaneous position; by axial displacement of the scanning coils; and by the use of auxiliary magnetic fields. Apparatus (the Figure, not shown) which includes an evacuable core (1) housing three guns 6, and deflection coils (7 and 9), and arranged to receive a faceplate and shadow mask, is disclosed.
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