DEVICE FOR AUTOMATIC FOCUSING OF OBJECTIVE Russian patent published in 1995 - IPC

FIELD: optical industry. SUBSTANCE: ultrasonic irradiator 2 of the device transmits signals into air at the directions of shooting object 19 and test-object 20. Signal is received by receivers 17 and 20. Electromagnetic energy radiators 18 and 21 turn on when receiving signal. Each irradiator transmits signal at the direction of basic object 1, which signal is received by corresponding receivers 3 or 4. Signals after being received are conversed into electric signals, which correspond to distance to objects 19 and 16. These signals enter units 6 and 7 for measuring time interval. Stoppage of time counters is performed when receiving the signals; time counters are turned by radiator 2 on. Signal passage time, being received from the counters, is transformed into distance, corresponding to distance from measuring surface of basic object 1 to objects-responders 16 and 19. Results of measurements are applied to the first input of adder 9 into circuit 8 for error extraction The results after being compared with reference voltage, are applied to the second input of adder 9 in form of distance error. The voltages are summed, and resulting sum is applied to tracking unit 10 of controlling focusing of objective 15. EFFECT: improved reliability of operation. 1 dwg