Generator für Bildschirmanzeige

摘要

An on-screen display generator for use in an image display system is disclosed. The on-screen display generator includes a main image signal source (10), and an auxiliary image signal source (20,90,82,92,84,86) which includes a controller (40,120,82,84,86,88) for varying the perceived brightness of the image represented by the auxiliary image signal in response to a first control signal. A video signal processor (30,25,102,104,106,108,110), coupled to the main image signal source (10) and the auxiliary image signal source (20,90,82,92,84,86), includes circuitry (104) for combining the main and auxiliary image signals to produce a combined image signal. The video signal processor further includes a controller (106) for varying the perceived brightness of the image represented by the combined image signal in response to a second control signal. A control signal generator (40,120,82,84,86,88) generates the first and the second control signals in such a manner that the perceived brightness of the auxiliary image signal remains substantially constant when the perceived brightness of the main image is varied. This on-screen display generator is disclosed as being embodied in a sleep timer in a television receiver.