Patent ID: 8598502

Claim:
A motionless focus evaluation test station for measuring detector position error in an electro-optic (EO) sensor, said EO sensor comprising an optical assembly that focuses collimated light onto a detector positioned substantially perpendicular to an optical axis of the test station at an unknown position d actual nominally at a known desired position d desired from said assembly, said EO sensor having no dynamic focusing capability to adjust detector position, said test station comprising: a positionally-fixed source that emits electromagnetic (EM) radiation that diverges along the optical axis of the test station, said EM radiation having a wavelength in a range between 0.2 micron and 30 microns; collimating optics that collimate the EM radiation and direct it along the optical axis to the EO sensor; a positionally-fixed target in the path of the diverging EM radiation, said target comprising a limiting aperture that exhibits an induced shift in optical focus at different positions along the aperture such that different positions on the target are imaged to different focal planes at the detector, said detector capturing an image of the target that is blurred to either side of the spatial position that is optically conjugate to the actual detector position; and a processor that processes the image to measure the blur as function of spatial position to measure the actual detector position d actual and output the detector position error Δd.