DEVICE FOR MAINTAINING TARGET SEPARATING DISTANCE BETWEEN OBJECT OF MAIN OPTICAL SYSTEM AND OPTICAL OUTPUT STAGE AND MAINTAINING METHOD

摘要

PROBLEM TO BE SOLVED: To provide a device for an automatic focusing system to detect zero by receiving a control signal from a loop for control and moving an optical output stage so as to maintain the target separating distance between an object and the optical output stage.;SOLUTION: A device is provided with laser sources 4 and 13 to generate incident laser beams and a pair of optical elements to be mounted to both sides of an optical output stage. The first optical element among the pair of optical elements deflects a laser beam toward an object. The object to reflect an incident beam forms a beam to be reflected backward toward the optical output stage. In addition, the second optical element deflects the reflected beam. Furthermore, a high-sensitivity location detector 16 receives the reflected beam at its input surface to obtain a representative output signal of the location of the reflected beam. Then a loop 7 for control interprets an output signal generated by the high-sensitivity location detector 16 and outputs a corresponding control signal. The control signal is computed by such a method as to make the difference zero between the target separating distance between the object and the optical output stage and the actual separating distance measured by the high-sensitivity location datector 16.;COPYRIGHT: (C)2000,JPO