| 摘要 |
PURPOSE:To obtain a clear TV picture image on a fluorescent screen by a main focussing lens through a combination of unipotential and bipotential type electron lens and specifying their mutual interval. CONSTITUTION:The electrode of a composite type electron lens consists of an arrangement of the conical first to fourth electrodes 1-4. When the potential for the electrodes are V1-V4, respectively, the first potential condition and the second one are set to V2<V1 or V3<V4 and V1 or V3<V2<=V4, respectively. The dimensional condition which determines the characteristics of such an electron lens system is the distance l between the unipotential type electron lens consisting of the first to third electrodes and the potential type lens consisting of the third and fourth electrodes. This distance l is set to 0.6D-1.5D. This can produce a clear TV picture image on a fluorescent screen by small diameter beam spots. |
