The effect of Coddington factors on aberration functions has been analysed using thin lens approximation with optical glass parameters. The dependence of spherical aberration on Coddington shape factor for the various optical glasses in real lens design was discussed using exact ray tracing for the optics education and training purposes. Thin lens approximation and thick lens design are generally taught with only lecturing method. But, thick lens design is closely related to the real life. Hence, it is more appropriate to teach thin lens approximation and thick lens design with real-life context based approach. Context based teaching can be effective in solving problems in which the subject is very difficult and irrelevant. It also provides extensive evidence for optics education that students are generally unable to correctly apply the concepts of lens design to optical instruments currently used. Therefore, the outline of real-life context based thick lens design lessons were proposed and explained in detail considering thin lens approximation.
Luminous power LED technology has been improving quite fast and it will replace completely the lighting components
that are used currently in the present decade due to its lighting advantages. This study was carried out to determine
illumination efficiencies of power LED drivers and optics. The buck-based type LED driver was selected for this study.
On this way, power LED driver circuit was designed using switching current regulator and circuit component values
were computed for maximum light output efficiency. A reflector which will enable uniform distribution of the
maximum power LED illumination to be obtained by using this driver circuit was investigated. In this case, diffusers and
Fresnel lenses were proposed depending on the use. Diffusers can be used for indoor iluminations combined with
reflectors. To this end, also Fresnel lenses were investigated.
It is well known that ion-assisted deposition (IAD) using a plasma source improves the optical and physical characteristics of optical thin films. A broad-beam cold-cathode plasma source was used in this study. The versatile ion source selected can easily be retrofitted into existing deposition chambers or new installations. This paper discusses characterization of the ions produced by the plasma source and analyzes the properties of thin films produced using the plasma source for IAD. Ion energy measurements were made using an ion energy analyzer for the determination of ion energy distribution functions (IEDFs). IEDFs were measured for three gases; argon, oxygen, and nitrogen. The ion characteristics in oxygen are focused on. The effect of pressure and drive current on the IEDFs of oxygen ions is discussed. Mean ion energies of oxygen as a function of pressure, drive voltage, and drive current were calculated. Since the density and quality of films are related to the ion current density during deposition, the effects of drive voltage, pressure, and the pumping speed of the system are discussed. Characteristics of TiO2 and Ta2O5 films deposited on silicon wafers and microscope slides were investigated. The conditions for moisture stability of these films were analyzed.
This study deals with lapping process with loose abrasives in large diameter lens manufacturing. Loose abrasive lapping, is a three-body abrasive process in which a fixed load is applied to a plate that presses a slurry consisting of a coolant and abrasive particles onto the optical surface being manufactured. This process is analyzed by examination of the influence of optical glass material parameters on material removal and surface roughness for lens manufacturing conditions. The model established for this analysis uses the concept of lateral fracture, which is based on removal of optical glass material by rolling abrasive particles. The particles remove glass material by lateral cracking. The concept of lateral fracture by rolling abrasive particles is verified as the lapping model, which was found to give a good description of the experimental results. Removal rates and lapping time values at the conventional removal depth are found and which will allow the automation of lapping process for lens manufacturing. The abrasive mineral Barton Garnet was used in the lapping experiments.
This study presents the athermalization of a forward looking IR system which is one of the tasks of a optomechanical engineer. 3D modeling and optical design of a forward looking IR system are done. Thermal and structural analyses are performed by using the finite element method. Initial conditions and obtained results are verified by a laboratory study. The system parameters are optimized for ensuring the system to perform at different environmental temperatures by determining temperature distributions, expansions and contractions.
The values of the quantum yield, its spectral dependence, and the external quantum efficiency of GaAlAs/GaAs transmission-mode photocathodes used in image intensification systems are computed based on the parameters of the internal quantum efficiency, the diffusion length, and the normalized surface recombination velocity. The variations for these parameters obtained are shown on the three orthogonal axes. Possible explanations and further lines of the investigation are also discussed.
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