METHOD AND DEVICE FOR CHECKING LENS CENTERING Russian patent published in 1995 - IPC

FIELD: optical engineering. SUBSTANCE: lenses to be checked are subjected to radiographic test of bundle of beams which build image of optical mark behind lenses to be checked. The image received is scaled by means of magnifying optical system and rotating lenses about geometrical axis of one lens. Magnified image of optical mark is transformed into videosignal by means of TV camera. Characteristic point is selected in the videosignal. Measurement interval is formed from selected characteristic point to the end point of roll-up along the line. Then measurement interval is transformed into voltage U_x. This voltage is memorized till end of the frame. Then the voltage is scaled with K coefficient. U_x and U_x voltages are compared with saw-tooth signal of TV roll-up along the line. Rough and precise TV mark signals are formed when saw-tooth voltage is equal to U_x и K·U_x and U_x и K·U_x voltages. Signals achieved are gated then in such a manner that each of them could exist within its own limited region of TV frame. Rough and precise electron mark signals are added with videosignal. Result of addition is represented onto the screen of cathode-ray tube. Direction of decentering is judged from shift of image of optical mark relatively the center of cathode-ray tube. Value of decentering is judged from swing of heating of rough and/or precise electron mark signals under rotation of lenses to be checked. Device has the following units which are placed in sequence: illuminator, glass with mark, projection optical system, basing unit provided with controlled optical system, magnifying optical system, TV camera, unit for selecting characteristic point, flip-flop, integrator, scaling amplifier, OR gate, two comparators, two univibrators, two AND gates, X coordinate counter, Y coordinate counter, saw-tooth voltage generator, permanent memory, display, adder. EFFECT: improved precision. 2 cl, 2 cl, 4 dwg