When the environment temperature has changed, then each parameter in infrared lens has also changed, thus the image quality became bad, so athermal technology is one of key technology in designing infrared lens. The temperature influence of each parameter in infrared lens is analyzed in the paper. In the paper, an athermal mid-wave infrared optical system with long focal length by Code-v optical design software was presented. The parameters of the athermal infrared system are 4.0 f/number, 704mm effective focal length (EFL) , 1° field of view and 3.7-4.8 μm spectrum region 100% cold shield efficiency. When the spatial frequency is 16lp/mm, the Modulation Transfer Function (MTF) of all the field of view was above 0.5 from the working temperature range -40℃ to 60℃. From the image quality and thermal analysis result, we knew that the lens had good athermal performance.
Ultraviolet lithography is the most important technology for the semiconductor manufacturer. The high resolution lithography objective lens is the key component of ultraviolet lithography.Aspheres are becoming more and more popular in optical design of lens systems.For traditional aspheres, non-zero terms of over 10th order are seldom used by optical designers.In the paper,we proposes a ultraviolet lithography objective lens with Q-type aspheres.The working wavelength is 193.368 nm, numerical aperture is 0.75,reduction ratio is 0.25, the thickness from the first lens to object is 60mm,the thickness from the last lens to image is 8.5mm,the total track length (from object to image) is 1186mm and image field of view is 26mm×10.5mm.The optical material in ultraviolet wave band is very few,only silica and CaF<sub>2</sub> can be used in engineering project.Because CaF<sub>2</sub> material is very expensive in cost,so we choose silica as the material of ultraviolet lithography objective lens. The ultraviolet lithography objective lens is consisted of twenty-three glass,the maximal aperture is 136.5mm eight aspheric surfaces are used to correct the off axis aberration and higher order aberration.We use the Q-type aspheres and traditional aspheres in the ultraviolet lithography objective lens,and compare the design results.
Thermal properties and dispersive capacity of diffractive optical elements were expounded in this paper, and the conclusion that optothermal expansion coefficient of diffractive optical element is independent of refractive index of the material was derived. The design method to athermalize the hybrid infrared optical system was studied, a new hybrid system with diffractive surface was structured on the foundation of refractive/reflective optical system using optical design software ZEMAX, and the surface was simulated by MATLAB. The image quality was improved obviously compared with the one without diffractive surface. The system worked at 3.7~4.8μm band with its’ effective focal length of 70mm, field of view of 2° and possessed better athermal performance in the temperature range -40°~+60°. The image quality achieved diffractive limit, besides, a compact structure, small volume and light weight were other advantages of the hybrid system.
For novel cooled 640×512 large focal plane array staring focal plane array (FPA) infrared detector with the picture clement size of 15 μm×15 μm,a mid-wave infrared step-zoom detection imaging system with a large FPA was presented in the paper.The manner of variational fov was accomplished by switching two lenses into the narrow fov system layout with mechanism framework.The parameters of the novel system are 4.0 f/number, 800mm/400mm effective focal length (EFL) and 3.7-4.8 μm spectrum region，100% cold shield efficiency.Image quality and thermal Analysis was evaluated by Code-v optical design software.At the spatial frequency 33lp/mm,the Modulation Transfer Function(MTF) was above 0.15 both the long EFL and short EFL in the working temperature range -35°C～55°C.
Reflective optics is used widely in optical systems for their achromatization, large aperture and lightweight compared with refractive systems.An infrared three-mirror optical system with large relative aperture working in the 8～12 micron long wavelength infrared band is designed by using four reflective mirrors. The design principle, design results are described in this paper. The system has a field of view with 1.41°. The MTF of the system is diffraction-limited and the distortion is less than 0.5%. The image quality is evaluated for each field,which shows that the design makes a good system with high image quality.
Compares with traditional optics,the difractive optical element(DOE) has unique property of minus dispersion.The
special state can be used in the optical system to improve performance,lighten weight and reduce volume effectively.In
the paper,an infrared optical system with DOE for LWIR thermal imager is proposed.The primary optical parameters of
thermal imager are wavelength range 8.0- 12.0μm,effective focal length (EFL) 150 mm,f/numbe 1.0 and field of view
8.58 degrees.The system uses uncooled infrared detector with 320×240 pixels and 45μm pixel size. The f/number
matches the sensitivity range of detector array. The infrared optical system is designed by CODE-V optical design
software.It is consisted of two lens,the materials of the two lenses are Germanium.The DOE is fabricated on the convex
of the first lens and it can be fabricated by diamond turning technology.The imaging quafity of the optical system
approached to diffraction limit.The value of modulation transfer function (MTF) at Nyquist frequency(11lp/mm) is great