• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.11a
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• pp.617-618
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• 2008

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.449-450
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• 2008

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.629-630
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• 2008

• Korean Journal of Optics and Photonics
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• v.6 no.3
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• pp.239-244
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• 1995

내부 전반사 홀로그램을 이용하여 마스크의 미세 패턴을 기록, 재생 결상하였다. 직각 프리즘과 쐐기 살 다발 가르개, 반사경을 이용하여 광학계를 구성하였으며 TIR 홀로그램의 특성을 조사하였다. 본 실험에서는 5mW의 출력과 633nm의 파장을 가진 He-Ne 레이저를 이용하여 Agfa 8E75 홀로그램 건판에 TIR 홀로그램을 기록하고 기준파의 복소 공액파인 재생파로써 홀로그램을 재생하였다. 홀로그램 건판과 마스크와의 간격을 $200\mu$m로 유지했을 때 약 $3\mu$m의 분해능을 가진 재생상을 얻었으며 $70\mu$W의 기록 광으로써 홀로그램을 기록하여 0.45%의 에돌이 효율을 얻었다. 본 실험을 통하여 렌즈를 쓰지 않는 TIR 홀로그래피의 평판 표시 소자 리소그라피 기술에 응용 가능성을 알아 보았다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.1
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• pp.71-77
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• 2015

Ultrasonic imprinting is a micropattern replication technology for a thermoplastic polymer surface that uses ultrasonic vibration energy; it has the advantages of a short cycle time and low energy consumption. Recently, ultrasonic imprinting has been further developed to extend its functionality: (i) selective ultrasonic imprinting using mask films and (ii) repetitive ultrasonic imprinting for composite pattern development. In this study, selective ultrasonic imprinting was combined with repetitive imprinting in order to replicate versatile micropatterns. For this purpose, a repetitive imprinting technology was further extended to utilize mask films, which enabled versatile micropatterns to be replicated using a single mold with micro-prism patterns. The replicated hybrid micropatterns were optically evaluated through laser light images, which showed that versatile optical diffusion characteristics can be obtained from the hybrid micropatterns.

• Korean Journal of Optics and Photonics
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• v.22 no.6
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• pp.247-255
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• 2011

The optical performance of LLF(Lenticular Lens Film)-based backlight was studied by using optical simulation as functions of the aspect ratio and the refractive index of lenticular lenses. In order to perform reliable simulation, the BSDF(bi-directional scattering distribution function) of the scattering dots on the bottom surface of the light guide plate was obtained as a superposition of the Lambertian and the elliptic Gaussian distribution components by comparing the experimental results and the simulation for the luminance distribution on the light guide. Based on this approach, an appropriate BSDF of the scattering dots of the light guide was constructed. The resultant values of the optimized aspect ratio and the refractive were found to be 1.25 and 1.65, respectively. In spite of the hybrid aspects of LLF incorporating both diffusing and collimating functions, the optical performance, in particular the on-axis luminance of LLF-based backlight was inferior by about 20% compared to that of conventional backlights adopting one prism film. However, the combination of two lenticular lens films resulted in comparable luminance gain as well as smooth decrease in the luminance with the viewing angle without exhibiting any side lobes.

• Transactions of Materials Processing
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• v.15 no.1 s.82
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• pp.71-75
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• 2006

In recent, various shapes of pattern in micron or nano scale are adapted in many applications due to their good mechanical or optical properties. Light guide panel (LGP) of the LCD is one of important applications for micro pattern and micro prism shape is one of the typical patterns. The size of the surface patterns in most applications is decreasing to the order of micron or even under micron. On the other hand, the area to be patterned keeps enlarging. These two trends in patterned products require tooling micro patterns on large surface, which has still many technical problems to be solved mainly due to pattern size and the tooling area. In this study, we fabricated prism shape of patterns using diamond cutting tool on some metal core and plastic core like PMMA. Some cutting conditions were investigated including cutting force, cutting depth and speed for different core materials.

• Proceedings of the KIEE Conference
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• 2002.11a
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• pp.254-256
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• 2002

광섬유, 마이크로렌즈, 마이크로 프리즘, 마이크로 스캐너로 구성된 단백질 분석용 초소형 형광측정 시스템을 설계하였다. SNR을 높이기 위해 단백질 패턴에 여기광이 수직이 아닌 비스듬하게 입사하는 구조를 제안하였으며 그 가능성을 실험적으로 확인하였다.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.09a
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• pp.110-113
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• 2005

In recent, various shapes of pattern in micron or nano scale are adapted in many applications due to their good mechanical or optical properties. Light guide panel (LGP) of the LCD is one of important applications for micro pattern and micro prism shape is one of the typical patterns. Many applications have the patterns on their surface and the size of the pattern keep decreasing down to the order of micron or even under micron. On the other hand, the area to be patterned keeps enlarging. These two trends in patterned products require tooling micro patterns on large surface, which has still many technical problems to be solved mainly due to pattern size and the tooling area. In this study, we fabricate prism shape of patterns using diamond cutting tool on some metal core and plastic core like PMMA Some of cutting conditions are investigated including cutting force, cutting depth and speed for different core materials.

• Korean Journal of Optics and Photonics
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• v.33 no.2
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• pp.67-73
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• 2022

In a head-mounted display (HMD) for virtual-reality applications, a narrow viewing angle is preferred to the usual, wide viewing angle because the HMD is positioned close in front of the user's eyes, and the display position is fixed. In this paper, we propose a new back-light unit (BLU) for implementing a narrow viewing angle, which is suitable for a HMD. By optimizing the scattering patterns in the light-guide-plate and inverse-prism structures, the viewing angle and correlations between structural parameters in the BLU components are analyzed with ray-tracing simulations. As a result, a double-angle inverse-prism structure incorporating the scattering patterns of a light-guide plate is chosen, which results in a 14% increase in center luminance, a 16% decrease in the vertical viewing angle, and a light efficiency of up to 70%, compared to a conventional BLU. Thus, the new BLU system is expected to be applied in a high-efficiency liquid crystal display.