| 摘要 |
1484914 Cathode-ray tubes SONY CORP 31 Oct 1974 [21 Dec 1973 4 June 1974] 47246/74 Heading H1D [Also in Division H4] In a television tube having a gun which includes two tubular electrodes coaxially arranged in succession along the beam path, modulation of the line scanning velocity by a signal derived from the transient change in the brightness component of the video signalto sharpen the image at regions of rapid brightness change-is achieved by forming that one of the two electrodes that is at a relatively lower potential in two parts which are axially separated along a vertical plane that is inclined relative to the axis of the tube, the control signal being applied across the two parts. In the three gun shadow mask colour tube shown in Figs. 1 and 2, the centre electrode G 4 of the unipotential main focusing lens is divided into parts G 4A and G 4B , the electrode potential Vf, Fig. 2, being applied to both parts, and the scanning velocity control signal E being applied between them. A similar arrangement is disclosed in a tube having a bipotential main focusing lens (Figs. 7 and 8, not shown), and in a monochrome tube. The control signal for the scanning velocity modulation is produced by applying the brightness component of the video signal to one end of a delay line which, in response to transient changes in the brightness component is short-circuited at its other end by a transistor, the once-delayed short-circuit signal being employed to intensity modulate the beam, and the twice-delayed reflected signal being subtracted from the original brightness component to provide the control signal for modulating the scanning velocity (Fig. 4, not shown).
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