| 摘要 |
PURPOSE:To make it possible to input patterns with simple constituton by shaping light, emitted by a display tube, into a character pattern through an optical filter and then by feeding it back to video amplifier via a light pen. CONSTITUTION:An electric signal is obtained by detecting by a light pen light outputted by display tube 24 and, after being waveform-shaped, applied to video amplifier 21, so that the detected pattern can be reproduced on display tube 24. For the purpose, an optical filter which transmits light only at a desired pattern part is provided on the display screen and the transmitted light is detected by light pen, so that the pattern on the optical filter can easily be led out as a video output signal. |
