We have designed a SWIR(Short Wavelength Infrared) optical zoom system for surveillance. The focal length of the optical zoom system was 50mm to 500mm for a 640x512 pixel detector. The spot diameter of the optical system was about less than 30um concerning the pixel pitch of the SWIR detector. The MTF of the optical system was about 0.3 at the edge field of view. In field test we have proved to be able to get the image of a target in 1.5 times longer distance than visibility range by using our optical system with a SWIR detector at the focal length of 300mm.
We have developed a SWIR (Short Wavelength Infrared) optical system for surveillance. The focal length of the optical system was 300 mm for a 640x512 pixel detector. The spatial resolution of the optical system has been designed less than 0.05 mrad. We have measured the spatial resolution to verify the optical performance. Also, we have observed a 2- cycle target at 3 km distance when the visibility was 1.7 km in the field test. We have proved to be able to get the image of a target by using our optical system with a SWIR detector in 1.5 times longer distance than the visibility range.
We have designed and manufactured an optical system with dual field of view (FOV) for an uncooled IR camera. Fnumber
of the optical system with five elements is given by F/1.04. FOVs are given by 8°x6° for narrow FOV and 24° x
18° for wide FOV. One of the five lenses is linearly moved along the optical axis not only to change FOV but also to
athermalize for the optical system. The movement of the lens is fulfilled with a stepping motor within a few
micrometers' accuracy. The athermalization is compensated for 100 K of the temperature difference. The optical system
is integrated into an uncooled IR detector engine to verify the optical performance of the dual FOV IR system. The
uncooled IR detector consists of 320x240 pixels with 25μm pitch. Minimum resolvable temperature difference (MRTD)
as measured values at each FOV will be presented in this paper.
In this paper, we report the capacitance-voltage (C-V) properties of metal-insulator-semiconductor (MIS) devices on CdTe/HgCdTe by the metalorganic chemical vapor deposition (MOCVD) and CdZnTe/HgCdTe by thermal evaporation. In MOCVD, CdTe layers are directly grown on HgCdTe using the metal organic sources of DMCd and DiPTe. HgCdTe layers are converted to n-type and the carrier concentration, ND is low 1015 cm-3 after Hg-vacancy annealing at 260 degrees Celsius. In thermal evaporation, CdZnTe passivation layers were deposited on HgCdTe surfaces after the surfaces were etched with 0.5 - 2.0% bromine in methanol solution. To investigate the electrical properties of the MIS devices, the C-V measurement is conducted at 80 K and 1 MHz. C-V curve of MIS devices on CdTe/HgCdTe by MOCVD has shown nearly flat band condition and large hysteresis, which is inferred to result from many defects in CdTe layer induced during Hg-vacancy annealing process. A negative flat band voltage (VFB approximately equals -2 V) and a small hysteresis have been observed for MIS devices on CdZnTe/HgCdTe by thermal evaporation. It is inferred that the negative flat band voltage results from residual Te4+ on the surface after etching with bromine in methanol solution.
A dynamic analysis of a flexure support system for a one- meter primary mirror in a space telescope is presented. It is assumed that the primary mirror is held by a three-point flexure support at the back surface. The design study is to be conducted with three different power spectral density functions (PSDF) and four different sized support systems. Mechanical responses of the mirror to each PSDF are to be examined. Using the finite-element analysis program, MSC/NASTRAN, the maximum root-mean-square values of the bending stress and the axial stress in the flexure system due to the launch loads are calculated. As a result, the stiffness and the strength of the flexure in the vertical (optical axis) and tangential directions to accommodate the launch loads are discussed.
This paper describes a design study of the KAO (Korea Astronomy Observatory) 1m telescope. The telescope uses an F/2.7 zerodur primary mirror which has a double arch back contour shape. For the zenith pointing, the primary mirror is to be held by a 6-point axial support system at the back surface. For Horizon, a 3-lateral support system is to be designed and located at the center of gravity of the mirror. In this paper, a parametric design study of a double arch back contour shape is to be performed to meet an optical surface deflection requirement, a surface RMS wavefront error of (lambda) divided by 10, using the finite element program, ANSYS, for the mechanical surface deformation, and the PCFRINGE program for the evaluation of the optical performance. Additionally, the static and modal frequency analysis of the truss structure and yoke were performed.