| 摘要 |
PURPOSE:To increase the visibility, by lowering the brightness within the character frame provided on a TV screen less than the brightness of periphery to secure a higher brightness of characters for display. CONSTITUTION:Brightness signal Y of a prescribed level is always supplied to the brightness signal input terminal 26 for the character to be displayed. When the character signal F is supplied from the character signal input terminal 28, the electronic switch 23 touches the Y side. As a result, the voltage having the level of the signal Y is delivered to the video signal output terminal 24 for the period during which the pulse of the signal F is produced. At the same time, the character frame signal input is connected to the electronic switch 22, and the character frame is compounded with the video signal input 20 to be applied to the switch 23. In such a way, the brightness within the character frame is lowered less than the ambient brightness when the character is displayed, thus ensuring an easy-to-see display of characters. |
