• Journal of Broadcast Engineering
• /
• v.21 no.4
• /
• pp.538-551
• /
• 2016

At the on-site of broadcasting production, the light source of tungsten halogen has been used as a primary light source for representing video images. Although tungsten halogen light has drawn attention in terms of the color reproducibility which is more similar to the sun light than that of other light sources, meanwhile it had problems in energy efficiency. Recently, the LED light source with high efficiency and long lifetime of the energy source has started getting attention as a substitute light source at the broadcast field. Because of the unique light emission principles, compared with tungsten halogen, LED light source has different characteristics in the quality of the light projected from the light source and color reproduction of the video image through a camera. These characteristics cause the delayed introduction of the LED as the broadcast light source. In this study we measured the quality characteristics of the flatness of the color reproduction and light of the LED light source and will present the experimental data whether it is suitable as the broadcasting light source compared to a reference light source of tungsten halogen. In addition, we suggested the future challenges and standards which are needed to expand usage of LED as a broadcast light source.

• Transactions of Materials Processing
• /
• v.14 no.5 s.77
• /
• pp.477-481
• /
• 2005

Wafer scale micro mirror array with high surface quality for small form factor (SFF) optical pick-up was fabricated by micro UV-molding. To replicate micro mirror array for SFF optical pick-up, a high- precision mold was fabricated using micro-machining technology. Wafer scale micro mirror array was UV-molded using the mold and then the process was optimized experimentally. The surface flatness and roughness of UV-molded micro mirror array were measured by white light scanning interferomety system and analyzed the transcribing characteristics. Finally, the measured flatness of UV-molded micro mirror away for SFF optical pick-up, which was fabricated in the optimum processing condition, was less than 70nm.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2005.05a
• /
• pp.47-50
• /
• 2005

In this study, micro mirror array for small form factor optical pick-up was replicated by micro UV-molding. First, mold for micro mirror array was fabricated using micromachining. Also, to analyze the characteristics of the surface quality, flatness of replicated mirror surface were measured by white light scanning inteferometry system. The results show that the micro mirror array with a sufficient surface quality can be obtained by polymer replication process.

• International Journal of Precision Engineering and Manufacturing
• /
• v.1 no.1
• /
• pp.98-105
• /
• 2000

The projectors using liquid crystal display(LCD) have faults such as low optical efficiency, low brightness and even heat generation. To solve these problems reflective-type spatial light modulators based on MEMS (Microelectromechanical Systems) technology have emerged. Digital Micromirror DeviceTM(DMDTM), which was already developed by Texas Instruments Inc., and Thin-film Micromirror ArrayTM(TMATM), which has been recently developed by Daewoo Electronics Co., are the representative examples. The display using TMATM has particularly much higher optical efficiency than other projectors. But the micromirrors manufactured by semiconductor processes have inevitable distortion because of the limitations of the manufacturing processes, so that the distortions of their surfaces have great influence on the optical efficiency of the projector. This study investigated the effects of mirror flatness on the optical performance, including the optical efficiency, of the TMATM projector. That is to say, as a part of the efforts to enhance the performance of the TMATM projector, how much influence the form errors of a micromirror surface exert on the optical efficiency and the modulation of gray scale of the projector were analyzed through a pertinent modeling and simulations.

• Korean Journal of Crystallography
• /
• v.12 no.1
• /
• pp.5-9
• /
• 2001

Nd/sub 0.05/Y/sub 0.95/Ca₄O(BO₃)₃(Nd:YCOB) single crystals were grown by the Czochralski method using a iridium crucible under N₂ atmosphere. Optimum growth parameters to get high quality of single crystals were 1.5∼2 mm/hr of growth rate and 10∼20 rpm of rotation rate. The grown crystals were transparent with light purple color and well-developed in cleavage planes. The crystal structure of Nd;YCOB were identified to monoclinic by XRD method. Crystal defects acting as light scattering centers, such as micro-pores, secondary phases, inclusions and cracks were not observed under the He-Ne laser illuminations. Three red, green, blue laser devices for the RGB laser oscillations were designed and then fabricated from the grown Nd:YCOB crystals according to the phase-matching angles of negative type-I which were φ=16.40°, 33.95° and θ=22.59° with the flatness of λ/6 at least, respectively.

• Aerospace Engineering and Technology
• /
• v.3 no.1
• /
• pp.126-133
• /
• 2004

Photogrammetry, as its name implies, is a 3-dimensional coordinate measuring technique that uses photographs as the fundamental medium for metrology. In the last few years the accuracy of photogrammetry has increased dramatically thanks to the rapid advance of digital camera manufacturing technique. This paper discusses photogrammetric measurement of the interface surface of MSC(Multi-Spectral Camera), which is a main payload of KOMPSAT-2. Total 24 paper targets on the objective surfaces and two scale bars calibrated with high accuracy were used for measurement, and multiple images were taken from 11 different camera angles by using a spacecraft rotation dolly. As a result of analysis, 3D coordinates of each targeted point were obtained and the flatness value based on the selected reference plane was calculated and compared with the pre-determined requirement. The technique acquired by this study is expected to be used for the 3D precise measurement of ultra-light weight and inflatable space structures such as a satellite antenna and a solar array.

• Tribology and Lubricants
• /
• v.26 no.5
• /
• pp.297-302
• /
• 2010

This study is focused on the resin layer formation of UV imprinting process by changing imprinting pressure and period. The mold shape is made for the process of window open over the pattern transfer area and the imprinting period is assigned as the time just before the UV light curing. The residual layer is measured by changing the imprinting period and pressure magnitude, and the measured data of residual layer provides useful information for the design of the process conditions of imprinting processes.

• Transactions of Materials Processing
• /
• v.13 no.3
• /
• pp.268-272
• /
• 2004

Transparent materials such as fused silica are widely utilized in optical and optoelectronics field because of its outstanding properties, such as transparency in a wide wavelength range, strong damage resistance for laser irradiation, and high thermal and chemical stability. In this study, we made a few micro patterns on the surface of fused silica plate using laser induced wet etching. KrF excimer laser was used as a light source. There were no burrs and micro cracks on the etched surface of fused silica and the flatness of the etched surface was fairly good. We investigated the influence of etchant upon the etch rate and quality in laser induced wet etching. Pyrene-acetone solution and toluene were used as etchant. In the side of etch rate, toluene solution was better than pyrene-acetone solution. But we made in wider range of energy density using pyrene-acetone solution. But pyrene-acetone solution gave us wider window of energy density for successful micro patterning.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2004.05a
• /
• pp.245-249
• /
• 2004

Transparent materials such as fused silica are important materials in optical and optoelectronics field because of its outstanding properties, such as transparency in a wide wavelength range, strong damage resistance for laser irradiation, and high thermal and chemical stability. However, these properties make it difficult to micromachine silica in micro-sized quantities. In this study, we fabricated a micro patterns on the surface of fused silica plate using laser induced wet etching. KrF excimer laser was used as a light source. There were no burrs and micro cracks on the etched surface of fused silica and the flatness of the etched surface was fairly good. We investigated the influence of etchant upon the etch rate and quality in laser induced wet etching. Pyrene-acetone, toluene, and pyrene-toluene solution were used as etchant. In the side of etch rate, toluene and pyrene-toluene solution were better than pyrene-acetone solution.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2007.08a
• /
• pp.644-647
• /
• 2007

We have fabricated vertical type organic thin film transistor using tris-8-hydroxyquinoline aluminum $(Alq_3)$. The effects of the growth control of $Alq_3$ thin layer on the grain structure and the flatness of film surface have been investigated. In addition, we have fabricated light emitting transistor and then investigated electroluminescent properties.