• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1998년도 추계종합학술대회 논문집
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• pp.977-980
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• 1998

A real-time holography system using LCD with CCD camera is proposed. In this system, the rainbow hologram is used since it can be reconstructed by white light source. And to record on CCD camera, a kind of in-line holography method is used to widen the width of the fringe pattern. The interference fringe pattern by proposed system is detected with CCD camera and transferred to the LCD A 3-dimensional image is reconstructed when a white light source illuminates the LCD. So it can represent 3 dimensional moving images at real-time. In this paper, to confirm the usefulness of the proposed method, the reconstructed image by holographic film is compared to the same reconstruct image by LCD. In the recording of the interferenced processing, the optimal ratio of the reference and object beam intenstiy is also investigated.

• 대한치과기공학회지
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• 제45권3호
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• pp.74-80
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• 2023

Purpose: This study aimed to evaluate the fit of the anterior and posterior teeth printed using two light-curing three-dimensional (3D) printers. Methods: Anterior and posterior single crowns were designed using dental software and were printed using 2 types of 3D printers, liquid crystal display (LCD) and digital light processing (DLP) (n=40). After the printed crown was scanned again from inside and outside, the prepared teeth were evaluated using a 3D program. To compare the root mean square (RMS) results among groups (α=0.05), the one-way analysis of variance and Tukey's test were used. Results: No statistically significant difference was found between the mean RMS values of the anterior and posterior teeth (p>0.05). However, as a result of comparing the internal, external, and tooth shapes, the DLP group showed significantly low errors in the inner and outer surfaces than LCD group (p<0.05). Conclusion: In terms of clinical acceptance standard of 100 ㎛, the fit of the anterior and posterior teeth fabricated using LCD and DLP was clinically acceptable.

• 한국광학회지
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• 제16권1호
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• pp.63-70
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• 2005

컬러 LCD(liquid crystal display) 모니터의 광학적 상에 대한 성능을 평가하기 위하여 LCD 모니터를 포함한 모든 광학계의 파장별 공간주파수 반응에 가중치를 부여한 진폭전달함수(modulation transfer function ; MTF)를 이용한 다색광전달함수(polychromatic modulation transfer function ; PMTF)를 제안한다. 서로 다른 진폭들을 갖는 적색(R), 녹색(G), 청색(B)의 3개의 막대형 LCD 단위물체를 이용한 컬러 LCD의 PMTF의 시뮬레이션 결과와 실험적 결과가 잘 일치하며, 이 결과 컬러 LCD의 결상성능은 단색으로 측정하는 MTF 및 가시광의 전파장대를 사용하는 백색광 MTF와는 다른 R, G, B의 3색에 대한 PMTF로 측정하늘 것이 보다 적절하다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 D
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• pp.1759-1761
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• 1999

The generation of pretilt in nematic liquid crystal(NLC)and electro-optical(EO) characteristics of photo-aligned twisted nematic (TN)-LCD with oblique p-polarized ultraviolet (UV) light irradiation on the two kinds of the soluble polyimide (PI) surfaces containing trifluoromethyl moieties were investigated. The generated pretilt angle of NLC is about $2.5^{\circ}$ with p-polarized UV light irradiation of $20^{\circ}$ on PI-3 surface at 20 min.; However pretilt angle of about $0.5^{\circ}$ are observed on PI-1 and PI-2 surfaces. The generated pretilt angle of NLC on PI-3 surface may be attributed to the trifluoromethyl moieties attached to the lateral benzene rings. The voltage-transmittance and response time characteristics of photo-aligned TN-LCD with p-polarized UV light irradiation of $20^{\circ}$ on PI-1 surfaceat at 20 min were almost same in comparison with the rubbing-aligned TN-LCD. However, the high threshold voltage and slow response are observed on PI-3 surface. Also, the decay time $\tau_d$ of photo-aligned TN-LCD is attributed to the anchoring energy of NLC.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1998년도 추계학술대회 논문집
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• pp.343-346
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• 1998

The generation of pretilt angle in nematic liquid crystal (NLC) and electro-optical (EO) characteristics of photo-aligned twisted nematic (TN)-LCD with oblique P-polarized ultraviolet (UV) light irradiation on the two kinds of the soluble polyimide (PI) surfaces containing trifluoromethyl moieties were investigated. The generated pretilt angle of NLC is about 2.5$^{\circ}$with P-polarized UV light irradiation of 20$^{\circ}$on PI-3 surface at 20 min.; However pretilt angle of about 0.5$^{\circ}$are observed on PI-1 and PI-2 surfaces. The generated pretilt angle of NLC on PI-3 surface may be attributed to the trifluoromethyl moieties attached to the lateral benzene rings. The voltage-transmittance and response time characteristics of photo-aligned TN-LCD with P-polarized UV light irradiation of 20$^{\circ}$on PI-1 surface at 20 min were almost same in comparison with the rubbing-aligned TN-LCD. However, the high threshold voltage and slow response are observed on PI-3 surface. Also, the decay time $\tau$$\sub$d/ of photo-aligned TN-LCD is attributed to the anchoring energy of NLC.

• ETRI Journal
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• 제36권2호
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• pp.232-241
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• 2014

A holographic display system with a 22-inch LCD panel is developed to provide a wide viewing angle and large holographic 3D image. It is realized by steering a narrow viewing window resulting from a very large pixel pitch compared to the wave length of the laser light. Point light sources and a lens array make it possible to arbitrarily control the position of the viewing window for a moving observer. The holographic display provides both eyes of the observer with a holographic 3D image using two vertically placed LCD panels and a beam splitter to support the holographic stereogram.

• 한국인쇄학회지
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• 제29권3호
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• pp.105-124
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• 2011

TFT-LCD consists of LCD panel on the top, circuit unit on the side and BLU on the bottom. The recent development issues of BLU-dependent TFT-LCD have been power consumption minimization, slimmerization and size maximization. As a result of this trend, LED is adopted as BLU instead of CCFL to increase brightness and to reduce thickness. In liquid crystal displays, the light efficiency is below 10% due to the loss of light in the path from a light source to an LCD panel and presence of absorptive polarizer. This low efficiency results in low brightness and high power consumption. One way to circumvent this situation is to use a reflective polarizer between backlight units and LCD panels. Since a nano-wire grid polarizer has been known as a reflective polarizer, an idea was proposed that it can be used for the enhancement of the brightness of LCD. The use of reflective polarizing film is increasing as edge type LED TV and 3D TV markets are growing. This study has been carried out to fabrication of the nano-wire grid polarizer(NWGP) and investigated the brightness enhancement of LCD through polarization recycling by placing a NWGP between an c and a backlight unit. NWGPs with a pitch of 200nm were fabricated using laser interference lithography and aluminum sputtering and wet etching. And The NWGP fabrication process was using by the UV imprinting and was applied to plastic PET film. In this case, the brightness of an LCD with NWGPs was 1.21 times higher than that without NWGPs due to polarization recycling.

• 한국전기전자재료학회논문지
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• 제21권3호
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• pp.213-216
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• 2008

The voltages for pixel electrodes on LCD panels are supplied with analog voltages from LCD Driver ICs (LDIs). The latest LDI developed for large LCD TV's has suffered from the degradation of analog output characteristics (target voltage: AVO and output voltage deviation: dVO). By the failure analysis, humps in $I_D-V_G$ curves have been observed in high voltage (HV) NMOS devices for input transistors in amplifiers. The hump is investigated to be the main cause of the deviation for the driving current in HV NMOS transistors. It also makes the matching between two input transistors worse and consequently aggravates the analog output characteristics. By simply modifying the active layout of HV NMOS transistors, this hump was removed and the analog characteristics (AVO &dVO) were improved significantly. In the help of the improved analog characteristics, it also became possible to reduce the size of the input transistors less than a half of conventional transistors and significantly improve the integration density of LDIs.

• 한국기계가공학회지
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• 제12권5호
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• pp.141-148
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• 2013

There are several problems in the conventional 2-D image processing and 3-D measurement systems. In the case of the 2-D image processing system, it is not possible to detect elevation data. In a 3-D measurement system, it requires a skillful operator and a lot of time for measuring data. Also, there exist data errors depending on operators. The limitation of detecting elevation data in the 2-D image processing system can be solved by laser diodes. In this study an algorithm that measures the accurate data in a subject face to be detected by combining laser diodes and a commercial CCD camera is developed. In the development process, a planar equation is developed using laser diodes and the equation is used to obtain a normal vector. Based on the results, an algorithm that transforms commercial CCD camera coordinates to 3-D coordinates is proposed. The completed measurement method will be applied to replace a manual measurement system for vehicle bodies and parts by an automated system.

• Journal of Microbiology and Biotechnology
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• 제32권10호
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• pp.1245-1252
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• 2022

Induced pluripotent stem cells (iPSCs) can be generated from somatic cells using Oct4, Sox2, Klf4, and c-Myc (OSKM). Small molecules can enhance reprogramming. Licochalcone D (LCD), a flavonoid compound present mainly in the roots of Glycyrrhiza inflata, acts on known signaling pathways involved in transcriptional activity and signal transduction, including the PGC1-α and MAPK families. In this study, we demonstrated that LCD improved reprogramming efficiency. LCD-treated iPSCs (LCD-iPSCs) expressed pluripotency-related genes Oct4, Sox2, Nanog, and Prdm14. Moreover, LCD-iPSCs differentiated into all three germ layers in vitro and formed chimeras. The mesenchymal-to-epithelial transition (MET) is critical for somatic cell reprogramming. We found that the expression levels of mesenchymal genes (Snail2 and Twist) decreased and those of epithelial genes (DSP, Cldn3, Crb3, and Ocln) dramatically increased in OR-MEF (OG2^+/+/ROSA26^+/+) cells treated with LCD for 3 days, indicating that MET effectively occurred in LCD-treated OR-MEF cells. Thus, LCD enhanced the generation of iPSCs from somatic cells by promoting MET at the early stages of reprogramming.