METHOD OF MEASURING LENS FOCAL DISTANCE Russian patent published in 2020 - IPC G01M11/02 

FIELD: measurement; optics.

SUBSTANCE: method can be used in measuring focal lengths of lenses, including long-focus large-size ones in a wide spectral range from ultraviolet to near infrared radiation. Method of measuring lens focal length comprises setting radiation source, a point test object, a controlled lens and a radiation matrix receiver in its focal plane, obtaining two images of a point test object, measuring distance d between two images of the point test object and calculating the focal distance. Behind the point test object, which is arranged as adjustable along the diameter, a collimator is installed, in the radiation flux from which two inclined mirrors are installed at an angle A to each other, and the focal distance is calculated by the formula: f'=d/2:tg A.

EFFECT: increased accuracy and manufacturability of measurement due to reduction of movements of units in measuring device.

3 cl, 1 dwg