• Proceedings of the Optical Society of Korea Conference
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• 2002.07a
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• pp.144-145
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• 2002

3차원 디스플레이 시스템의 구현을 위해 다양한 방법으로 연구가 진행되고 있는데 Stereoscopic 방법에 비해 IP(Integral Photography)방식은 비안경식이고 시야각과 시점 이동 면에 있어서 좀더 나은 특성을 가지고 있다. n에 대한 연구는 입체 영상의 해상도를 넓히고, 시야각을 넓히며, 또한 동영상을 구현하기 위한 방향으로 진행되고 있다. 여기서는 IP에서 동영상 구현에 대한 새로운 방법을 제시하고자 한다. (중략)

• Proceedings of the Optical Society of Korea Conference
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• 2004.07a
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• pp.70-71
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• 2004

Back light unit(BLU) using a microlens fabricated by the modified LIGA process for the liquid crystal display(LCD) is proposed, and some experimental results are presented. To realize the back light unit using microlens pattern, LIGA and reflow process are used.

• Korean Chemical Engineering Research
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• v.52 no.3
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• pp.321-327
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• 2014

Polymer dispersed liquid crystal lenses of the cell gap of $11{\mu}m$ and $30{\mu}m$ were made from a uniformly dispersed mixture of 40 wt% NOA65 prepolymer - 60 wt% E7 liquid crystal with the variations of the additional photoinitiator. The photoinitiator, benzophenone of 5.0 wt% was originally in the commercial prepolymer NOA65. In this works, the influence of the benzophenone amount intentionally added in the commercial NOA65 on the electrical properties of polymer dispersed liquid crystal lens for smart electronic glasses. The additional quantities of the photoinitiator were 1, 2, 4, 8 and 16 wt% of the weight of NOA65 - E7 mixture. All the electro-optical properties of the sample with added benzophenone such as the driving voltage, the slope of the linear region, the response time and contrast ratio were more improved than that of commercial NOA65 only. These improvements were due to the increase of the average size of E7 liquid crystal droplets in the samples with the increase of the added benzophenon amount. The liquid crystal droplet size was increased from $5.3{\mu}m$ to $12.2{\mu}m$ when the photoinitiator was added from 0 wt% to 8 wt%. At the same concentration range of the photoinitiator, the driving voltage was ranged from 11.1 V to 17.3 V. The slopes of the linear region were in the range of 10.35~13.96 %T/V, which were more enhanced than that of NOA65 without the additional benzophenone. In particular, though the deteriorations by cell gap of $11{\mu}m$ were so effective to offset the influence of the added benzophenone for both rising and falling response time, it is confirmed that there were still somewhat improvement by the additional benzophenone. Response time and contrast ratios of all the samples with excess benzophenone were slightly enhanced.

• Analytical Science and Technology
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• v.8 no.4
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• pp.1101-1108
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• 1995

Acousto-optic tunable filter is a compact, all solid state electronic dispersive device. It is based on the acousto-optic interaction in an anisotropic crystal. Compared to conventional grating monochromators. the AOTF has no moving parts, wider spectral tuning range (from UV through visible and near-IR to IR), higher throughput, higher resolution, faster scanning (${\mu}s$) and random wavelength access. These features make it possible to use the filter to develop novel instruments which are not possible otherwise. The instrument development and unique advantages of such AOTF based instruments including the multidimensional fluorimeter, the multiwavelength thermal lens spectrometer, and the detectors for HPLC and flow injection analysis are described.

• Design & Manufacturing
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• v.7 no.1
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• pp.55-59
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• 2013

A Light Emitting Diode(LED) is a semiconductor device which converts electricity into light. LEDs are widely used in a field of illumination, LCD(Liquid Crystal Display) backlight, mobile signals because they have several merits, such as low power consumption, long lifetime, high brightness, fast response, environment friendly. In general, LEDs production does die bonding and wire bonding on board, and do silicon and phosphor dispensing to protect LED chip and improve brightness. Then lens molding process is performed using mixed liquid silicon rubber(LSR) by resin and hardener. A mixture of resin and hardener affect the optical characteristics of the LED lens. In this paper, computational design of static mixer was performed for mixing of liquid silicon. To evaluate characteristic of mixing efficiency, finite element model of static mixer was generated, and fluidic analysis was performed according to length of mixing element. Finally, optimal condition of length of mixing element was applied to static mixer from result of fluidic analysis.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2006.05a
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• pp.239-242
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• 2006

LCD-BLU (Liquid Crystal Display - Back Light Unit) is one of kernel parts of LCD unit and it consists of several optical sheets(such as prism, diffuser and protector sheets), LGP (Light Guiding Plate), light source (CCFL or LED) and mold frame. The LGP of LCD-BLU is usually manufactured by forming numerous dots with $50{\sim}200$ um in diameter on it by etching process. But the surface of the etched dots of LGP is very rough due to the characteristics of the etching process during the mold fabrication, so that its light loss is high along with the dispersion of light into the surface. Accordingly, there is a limit in raising the luminance of LCD-BLU. In order to overcome the limit of current etched dot patterned LGP, optical pattern design with 50um micro-lens was applied in the present study. The micro-lens pattern fabricated by modified LiGA with thermal reflow process was applied to the optical design of LGP. The attention was paid to the effects of different aspect ratio (i.e. $0.2{\sim}0.5$) of optical pattern conditions to the brightness distribution of BLU with micro-lens patterned LGP. Finally, high aspect ratio micro-lens patterned LGP showed superior results to the one made by low aspect ratio in average luminance.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.75-76
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• 2006

LCD-BLU (Liquid Crystal Display - Back Light Unit) is one of kernel parts of LCD unit and it consists of several optical sheets(such as prism, diffuser and protector sheets), LCP (Light Guide Plate), light source (CCFL or LED) and mold frame. The LGP of LCD-BLU is usually manufactured by forming numerous dots with $50{\sim}200{\mu}m$ in diameter on it by erosion method. But the surface of the erosion dots of LGP is very rough due to the characteristics of the erosion process during the mold fabrication, so that its light loss is high along with the dispersion of light into the surface. Accordingly, there is a limit in raising the luminance of LCD-BLU. In order to overcome the limit of current dot patterned LGP, optical pattern design with $50{\mu}m$ micro-lens was applied in the present study. Especially, the negative and positive micro-lens pattern fabricated by modified LiGA with thermal reflow process was applied to the optical design of LGP. The attention was paid to the effects of different pattern conditions to the brightness distribution of BLU with micro-lens patterned LGP. Finally, negative micro-lens patterned LGP showed superior results to the one made by positive in average luminance.

• Korean Journal of Optics and Photonics
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• v.16 no.3
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• pp.201-208
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• 2005

In order to realize a 3-D stereoscopic display module with alternating illumination angles, several conditions required for a lenticular lens sheet were established, and then both the lens specification and the module structure were designed. Also the performance of the stereoscopic module and its tolerance characteristics were evaluated by simulating the intensity distribution on the observation plane with a finite-ray tracing technique. From the evaluation, it was known that an intersection area between two adjacent lenses should not be filled and that the lateral mismatch between a planar liquid crystal shutter and a lens sheet should be minimized.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.1
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• pp.44-51
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• 2004

Fractal-space multiplexing using a moving window(MW) can multiplex holograms by moving a window left and right. and up and down. But, crosstalk occurs by two neighboring moving windows in the vertical direction of the holographic memory system and limits high-density information recording. Accordingly, we analyzed the crosstalk with the focal length of lens, the distance of MW, and the number of multiplexed hologram to record high-density infromation and presented the optical experimental results of fractal-space multiplexing using volumetric photorefractive crystal and disc type photopolymer.

• Journal of the Korean Graphic Arts Communication Society
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• v.14 no.1
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• pp.89-114
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• 1996

Liquid crystal-polymer composite(LCPC) films consisting of a continuous LC phase embedded in a three-dimensional network of polymer matrix are formed by photopolymerization-induced phase separ on. The LCPC films are switched from a light-scattering stats to a highly transparent stats on the application of electric fields. Since the alignment of LC molecular determines the electro-optical properties of films, the requirement for good contrast is to generate the nematic phase at high concentration. On the other hand, the concentration of UV-curable monomer must be increased above some critical value to from the flexible matrix of unbounded polymer. The mixing ratio of LC and UV-curable monomer affects the electro-optical and viscoelastic properties of LCPD films in two opposing ways. By controlling the phase separation process, at an LC fraction of 0.7, the maximum performance of LCPC films has been achieved, the response time of which is 2ms on the application of electric fields.