Design and manufacture of an athermalication high-speed lens with low veiling glare

摘要

Advanced optical imaging systems should have high imaging quality and robotic environmental suitability. Such a near-infrared lens with the Pitzval style is designed and developed. Its operation wavelength is from 0.72 μm to 1.0 μm and its relative aperture as high as 1:2. Its passive athermalization design to suit for the wide operation temperature range from -45 °C to 60 °C is implemented through optimal selection of its optical glasses and opto-mechamical structure. Sharp ghost image due to even reflection at optical surfaces is eliminated with our suggested means, and thus stray light within its image plane is both low and uniform even under backlighting. The Modulation Transfer Function (MTF) of the designed lens at the Niquest spatial frequency 90 lines/mm of focal plane array detector is higher than 0.6 within its operation temperature range and its entire field of view. Eighty percent of its diffraction encircled energy is within one pixel of the detector. Its point source transmittance (PST) when the illuminating off-angle of point source is from 5 to 60 degrees, which is just out of its field of view, is computed through modeling and simulation, and as low as between 10~(-3) to 10~(-11). The experimentally measured MTF values and veiling glare index of our developed lens reaches respectively to 0.61 and 0.372% and validates our suggested design in the paper.