| 摘要 |
PURPOSE:To provide a focusing type shadow mask stable in its operation by utilizing a holding and insulating means not having electron storage effect and additional effect due to said effect. CONSTITUTION:(a) A voltage nonlinear resistance element 44 (hereafter called element) is conductively fixed as a spacer between two masks 41, 42 constituting a focusing mask. (b) In order to provide only a differential voltage between the masks preventing any current flow, a very thin insulating material 45 is inserted between the element 44 and the mask 41. Thus, power consumption can be suppressed at the mask. (c) By connecting one of the masks to earth potential or another potential lower than Vo, potential difference between the masks is stabilized. (d) An arrow in the drawing shows the incidence direction of an electron beam. Potential difference caused due to the electron beam entering the mask 41 is held and stabilized by a condenser 47. If the condenser 47 is sealed in a vacuum vessel 1, it is possible to hold stable potential difference without using an introducing terminal for focusing mask power supply. |
