METHOD OF MEASURING LENS TRANSMISSION GAIN Russian patent published in 1994 - IPC

FIELD: test equipment. SUBSTANCE: three lenses are taken for testing 1, 2 and 3. Combinations of two lenses mounted in series onto the same optical axis are chosen in turn. Spherical mirror 7 is installed by its center of curvature in the focus of lens in front of lens 1. The mirror is irradiated by convergent beam which has aperture angle being close to aperture angle of lenses under test. Photodetector 8 is installed in front of tested lenses in the path of radiation flux, reflected from mirror 7, and signal a is registered. Mirror 7 is installed behind lens 2 - center of curvature is in the case in its focus. Lenses 1 and 2 are irradiated by convergent beam with aperture angle being close to aperture angle of lenses under test. Parallel pass of the beams are formed between the first and the second controlled lenses, and signal b is registered. Then signals c and d are detected in the output of photodetector after the first and the third and the second lenses and the third lenses are installed in radiation flux. Transmission gains of the lenses are calculated according to taken results. EFFECT: improved precision. 3 dwg