Infrared optical lens comprising two layers of harmonic diffraction surfaces

Abstract

The invention discloses an infrared optical lens comprising two layers of harmonic diffraction surfaces, which belongs to the technical field of optical imaging. The infrared optical lens comprises two refraction / harmonic diffraction lenses and a spacer, wherein the two refraction / harmonic diffraction lenses are provided with spherical surfaces and harmonic diffraction surfaces using non-spherical surfaces as substrates; the depth H1 of the two harmonic diffraction surfaces is more than 65 mu m and less than 80 mu m, and the depth H2 of the two harmonic diffraction surfaces is equal to 2.04*H1; the two refraction / harmonic diffraction lenses are arranged coaxially; and the two harmonic diffraction surfaces are adjacent to each other and the central positions of the two harmonic diffractionsurfaces maintain a certain gap through the spacer. Through the infrared optical lens, the problem that because the diffraction efficiencies of the common single-layer diffraction element and the single-layer diffraction element depend on the wavelength, the contrast is reduced is solved, the diffraction efficiencies are distributed uniformly on a wavelength band of 8 to 14 mu m and reaches over 94 to 97.5 percent, the position color difference and a secondary spectrum can be controlled better and a transfer function is modulated to be close to a diffraction limit, so the infrared optical lens has the characteristics of excellent image quality and capacity of meeting high requirements of a military detection system.

Description

technical field [0001] The invention belongs to the field of optical technology, and relates to an optical lens, in particular to a long-wavelength wide-band infrared optical lens using a double-layer harmonic diffraction surface. Background technique [0002] Due to their unique dispersion function and temperature effect, single-layer diffractive elements and single-layer harmonic diffractive elements have incomparable advantages in achromatic and thermal difference compensation. However, because their diffraction efficiency depends on wavelength, it will deviate from the design wavelength , the diffraction efficiency decreases, resulting in stray light, which reduces the imaging contrast of the system and limits the application in the field of broadband imaging. In order to solve this problem, the research of multi-layer diffraction elements has been carried out at home and abroad. [0003] The website is http / / www.sheying8.com / article / 56 / 60 / 20060820303.shtml The report o...

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Problems solved by technology

[0006] The purpose of the present invention is to extend the application of multi-layer diffraction elements to the long-wave infrared wide band, so as to solve the problem that the diffraction efficiency of single-layer diffraction and single-layer harmonic diffraction elements decreases in the long-wave infrared wide band. Infrared Optical Lens

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