LIQUID CRYSTAL DIAPHRAGM FOR OPTICAL SYSTEMS Russian patent published in 1995 - IPC

FIELD: optical systems for photocameras. SUBSTANCE: diaphragm has concentric liquid-crystal annular areas. Moreover, area of any subsequent zone is twice as big as previous one. Control terminals of liquid-crystal zones are connected with information outputs of analog-to-digital converter in such a manner, that minimal area zone is connected to output of junior binary digit, the subsequent zone is connected to output of older digit and so on. Voltage is applied to input of the analog-to-digital converter, which voltage is proportional to value of light flux. Digital signal at analog-to-converter output controls light transmission of concentric zones according to doubled-weighed coding principle. As a result, light transmission of the whole diaphragm is changed, which diaphragm is mounted at aperture plane of optical system. EFFECT: improved reliability of operation. 1 dwg