| 摘要 |
<p>Cathode ray tube display apparatus comprises a cathode ray display tube (210) in which an electron beam spot is scanned in a raster pattern to produce an output image. Drive means (200) generates drive voltages on the focus electrode, first and second grid electrodes, and a cathode of the cathode ray tube to generate the electron beam spot in the cathode ray tube. Spot size control means (120) simultaneously varies, in response to a spot control signal, the voltages generated on the focus electrode, first and second grid electrodes and the cathode by the drive means to vary the size of the electron beam spot in the cathode ray tube.</p> |
