基本信息:
- 专利标题： Display device including a black level setting circuit
- 专利标题（中）：用于设定黑色电平电压的显示装置的电路。
- 申请号：EP93203654.4 申请日：1993-12-23
- 公开(公告)号：EP0605921A2 公开(公告)日：1994-07-13
- 发明人： Van Amesfoort, Alfonsus Maria
- 申请人： Philips Electronics N.V.
- 申请人地址： Groenewoudseweg 1 5621 BA Eindhoven NL
- 专利权人： Philips Electronics N.V.
- 当前专利权人： Philips Electronics N.V.
- 当前专利权人地址： Groenewoudseweg 1 5621 BA Eindhoven NL
- 代理机构： Kooiman, Josephus Johannes Antonius
- 优先权： EP92204090 19921228
- 主分类号： H04N9/72
- IPC分类号： H04N9/72
摘要：
Known display devices include a video signal processing circuit with a black level setting circuit, which black level setting circuit measures the black level of the video signal, for example, during the field retrace interval by making use of an extra output of the video output stage.
However, the measured black level comprises a line-frequency interference component which is caused by a parasitic capacitance in the display tube.
The line-frequency interference component is fully compensated for by coupling one side of a secondary winding of a transformer required for the focusing voltage to be generated to a first capacitor, the other terminal of which is connected to the measuring input of the black level setting circuit and by coupling at least a second and a third capacitor across the secondary winding of the transformer.
However, the measured black level comprises a line-frequency interference component which is caused by a parasitic capacitance in the display tube.
The line-frequency interference component is fully compensated for by coupling one side of a secondary winding of a transformer required for the focusing voltage to be generated to a first capacitor, the other terminal of which is connected to the measuring input of the black level setting circuit and by coupling at least a second and a third capacitor across the secondary winding of the transformer.
公开/授权文献:
- EP0605921B1 Display device including a black level setting circuit 公开/授权日：1999-05-06