| 摘要 |
<p>13 "Colour display tube:. By providing a field correction element (30) in the peripheral field of a focusing lens of an electron gun system of a colour display tube, it is possible to reduce the potential differences between the electrodes of the focusing lens necessary for the horizontal and vertical focusing, respectively, to acceptable values (between minus 100 to plus 200 volts). The field correction element (30) consists of a plate (31) which extends substantially perpendicularly to the electron beams and has elongate or square apertures (32, 33, 34) through which the electron beams (6, 7, 8) pass. It is also possible to perform convergence corrections by means of such a field correction element.</p> |
