GB1356604A - Colour display cathode ray tube apparatus - Google Patents

Abstract

1356604 Cathode-ray tube systems PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd 17 Sept 1971 [22 Sept 1970] 43399/71 Heading H4T In a colour display arrangement employing a cathode-ray tube of the "penetration" type, i.e., a tube in which the colour produced is determined by the energy of the electron beam, changes in dimensions, luminance and focus which result when the EHT is changed to produce different colours are corrected under the control of a colour information register supplied with an n-bit colour information signal. Fig. 1, shows the general arrangement in which colour register 22 supplied with a two-bit colour signal specifying the colours Green Yellow, Orange and Red, provides a four-level output which controls the gains of amplifiers 15 in the X and Y deflection channels and via circuit 24, produces a four-level reference voltage which controls the beam intensity via circuit 28 and via switch 26, controls the magnitude of the EHT from source 25 and the focusing voltage via circuit 27. Fig. 5, shows the actual circuit configuration employed. The invention may be employed in a colour television receiver by supplying video signals to the cathode 5 via amplifier 11 or the deflection circuits may be driven to cause the beam to trace Alpha- Numeric characters (Fig. 2) and the necessary blanking signals supplied to amplifier 11.