| 摘要 |
A projection television display apparatus comprises a display device responsive to a video signal for forming an image (M) in a raster (SR) for the projection thereof. A display screen (700) receives the raster (SR) and image (M) projected thereon. A photo sensor (S) is located adjacent to an edge of the display screen (700) for illumination by projection of the image (M). The photo sensor (S) generates an output signal in accordance the illumination. A controller (900) is coupled to the display device for controlling the size of the raster (SR). The projected image (M) within the raster (SR) illuminates the photo sensor (S) when the raster (SR) has a first size, and the projected image (M) within the raster (SR) fails to illuminate the photo sensor (S) when the raster (SR) has a second size. <IMAGE> |
