| 摘要 |
PURPOSE:To improve the white color reproducibility of a screen dark part, etc., by adjusting the cut-off voltage of an electron gun by using a constant current source, composed of an element with current saturation characteristics such as a transistor, for current supply to a variable contant-voltage source. CONSTITUTION:To variable constant-voltage sources 11R, 11G and 11B are supplied constant currents from constant current sources 13R, 13G and 13B. Constant current sources make use of current saturation characteristics of transistors and bipolar transistors 14, for example, are used to form them together with variable resistors 15 for determining current values. While attention is given so that transistors operate in active regions at any times, variable resistors 15 are adjusted to supply minimum currents required by variable voltage sources 11R, 11G and 11B to maintain constant voltage characteristics. |
