This paper introduces the tolerancing and design–for–manufacture in the catadioptric telescope for the remote sensing instrument (RSI) in the FORMOSAT–8 satellites program. The study utilized wavefront differential tolerance analysis to accelerate the tolerancing process efficiently. To address potential performance variations stemming from manufacture, assembly or alignment regulations, compensators were used to model these adjustments. The outcome delves into the strategic choices of specification and ion beam figuring (IBF) to trade–off manufacturability within the RSI system.
Aluminum doped zinc oxide (AZO) films with the aluminum concentration of 1.5 at.% were fabricated by co-sputtering dual metallic targets, Al and Zn, under the oxygen partial pressure of 1.3×10-4 torr. The total pressure was kept at 2.3 ×10-4 torr during the deposition. The poly-crystalline structure, optical property and conductivity of the films were investigated by XRD, UV-VIS-IR spectrometer and Hall measurement, respectively. The more intense ZnO crystallinity of (002), larger grain size, smaller d-spacing and highest carrier concentrations were observed on the as deposited AZO film which had the lowest resistivity of 7.8 ×10-4 Ω•cm. Comparing the AZO films post-annealed in atmosphere, in vacuum and in hydrogen ambiance, the structures processed in vacuum and hydrogen ambiance remained the good ZnO crystallinity in the film resulting from the oxygen deficient state of the films after post annealing processes. The better thermal stability of resistivity was observed in the films post-annealed in hydrogen ambiance due to the formation of the shallow donor in the film. Furthermore, the resistivity increased as increasing the post-annealing temperature in atmosphere. When the as-deposited film were post-annealed at temperature of 400 °C, the resistivity was about more than two orders of magnitude than that of the as-deposited film resulting from the decrease of the donor concentration and mobility in the AZO film. The variation of the carrier concentration in the AZO film also shifted the energy band gap. However, the average visible transmittance of all AZO films in this study was above 80 % regardless of the deposition and post-annealing conditions.
Cesium iodide (CsI) and sodium iodide (NaI) are good scintillators due to their high luminescence efficiency. These alkali halides can be excited by ultra-violet or by ionizing radiation. In this study, CsI and its Na-doped films about 8 μm thick were deposited by thermal evaporation boat without heating substrates at high deposition rates of 30, 50, 70, 90, and 110 nm/sec, respectively. The as-deposited films were sequentially deposited a silicon dioxide film to protect from deliquesce. And, the films were also post-annealed in vacuum at 150, 200, 250, and 300 °C, respectively. We calculated the packing densities of the samples according to the measurements of Fourier transform infrared spectroscopy (FTIR) and observed the luminescence properties by photoluminescence (PL) system. The surfaces and cross sections of the films were investigated by scanning electron microscope (SEM). From the above measurements we can find the optimal deposition rate of 90 nm/sec and post-annealing temperature of 250 °C in vacuum for the asdeposited cesium iodide and its sodium-doped films.
Dense Wavelength Division Multiplexers (DWDM), a kind of narrow band-pass filter, are extremely sensitive to the optical thickness error in each composite layer. Therefore to have a large useful coating area is extreme difficult because of the uniformity problem. To enlarge the useful coating area it is necessary to improve their design and their fabrication. In this study, we discuss how the tooling factors at different positions and for different materials are related to the optical performance of the design. 100GHz DWDM filters were fabricated by E-gun evaporation with ion-assisted deposition (IAD). To improve the coating uniformity, an analysis technique called shaping tooling factor (STF) was used to analyze the deviation of the optical thickness in different materials so as to enlarge the useful coating area. Also a technique of etching the deposited layers with oxygen ions was introduced. When the above techniques were applied in the fabrication of 100 GHz DWDM filters, the uniformity was better than +/-0.002% over an area of 72 mm in diameter and better than +/-0.0006% over 20mm in diameter.
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