• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.401-402
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• 2008

We proposed a single gap transflective liquid crystal display (LCD) using a vertically aligned (VA) liquid crystal cell and circular polarizer. The conventional VA transflective LCDs have problems that there required several compensation films and voltage-dependent transmittance and reflectance curves do not match each other. To solve these problems, we used circular polarizer and optimized the condition of insulator thickness in the transmissive part and reflective part. Also, we used the patterned vertical alignment (PVA) mode for wide viewing angle in transmissive part. Consequently, this device realized transflective LCD with a single cell gap and single gamma curve.

• Korean Journal of Optics and Photonics
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• v.10 no.4
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• pp.279-282
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• 1999

We designed and fabricated a single polarizer mode bistable twisted nematic liquid crystal display by employing a wide-band λ/4 retardation film to enhance the dark state property. We theoretically and experimentally confirmed the necessity of a wide- band λ/4 retardation film in a single polarizer mode. We obtained brighter image than previous reflective BTN LCDs.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.479-482
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• 2004

We report a method for simultaneous measurements of cell gap, twist angle, birefringence dispersion of liquid crystal (LC) material and alignment directions in filled reflective LC cells. The method is based on spectral measurements of the LC cell reflectivity for three orientations ($0^{\circ},45^{\circ},90^{\circ}$) of the exit polarizer and may be applied for LC cells with low and high gaps.

• Proceedings of the Optical Society of Korea Conference
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• 2001.02a
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• pp.140-141
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• 2001

반사형 STN-LCD (supertwisted nematic liquid crystal display) 는 많은 display에서 사용되고 있는 LCD mode 중의 하나이다. 그러나 현재 많이 사용되는 반사형 STN-LCD는 그림 1과 같이 한 장의 polarizer와 두장의 retardation film을 사용하는 구조이므로 각각의 component에 대한 parameter들에 의해 display의 표시 성능이 좌우된다. 먼저 Reflective STN-LCD의 보상에 필요한 parameter를 살펴보면, 그림 1과 같이 5개 ( $\alpha$, ø$_1$, ø$_2$, 각 retarder의 retardation : Δnd$_1$, Δnd$_2$)의 parameter의 결정이 필요하다. (중략)

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.10
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• pp.908-913
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• 2003

We have performed computer simulation to obtain electro-optic characteristics of reflective hybrid aligned nematic liquid crystal displays (LCDs) driven by fringe field. The results show that the optimal retardation value (dΔn) of the cell is 0.289 ${\mu}$m, which allows for the cell to have a practical cell gap of larger than 3 ${\mu}$m when manufacturing. A reflectance of the dark state is only 0.114 % for an incident light 550 nm. At this condition, the light efficiency of white state reaches 92.7 %. The display with optimized cell parameters shows that the contrast ratio greater than 5 exists over 600 of polar angle in all directions and lower driving voltage than that of fringe-field driven homogeneously aligned reflective LCD.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.587-589
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• 2009

The mode (reflective and transmissive) switchable LCD has been developed by using a treated SR (Selective Reflector) polarizer. We believe that our approach will be a solution to overcome weak points for a reflective and transflective mode in a dark environment and a transmissive mode in a bright environment. Therefore, this can minimize power consumption, and also be easily fabricated in a current manufacturing process, ready for large sizes.

• Current Optics and Photonics
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• v.4 no.4
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• pp.353-360
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• 2020

Adopting an elaborately designed reflective objective consisting of four mirrors, we have developed a rotating-polarizer-type microspot spectroscopic ellipsometer (SE) with an ultra-small spot size. The diameter of the focused beam, whether evaluated using a direct-image method or a knife-edge method, is less than 8.4 ㎛. After proper correction for the polarizing effect of the mirrors in the reflective objective, we unambiguously determine the dispersion of the complex refractive index and the thickness of monolayer MoS₂ using the measured microspot-spectroellipsometric data. The measured ellipsometric spectra are sensitive enough to identify small variations in thickness of MoS₂ flakes, which ranged from 0.48 nm to 0.67 nm.

• Journal of Information Display
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• v.12 no.3
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• pp.115-119
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• 2011

Optically isotropic liquid crystal (LC) mixture such as blue-phase LC and nanostructured LC composites exhibit the advantages of fast response time, high contrast ratio and wide-viewing angle due to the induced birefringence along the horizontal electric field. Utilizing this mixture, a novel single cell gap in-plane switching-type polymer-stabilized blue-phase transflective liquid crystal display by embedding the nanowire grid polarizer as a polarization-dependent reflective polarizer in the R region is proposed. This device can be used as a normal black mode without any quarter-wave plate or patterned in-cell phase retarder. Moreover, the transmittance is identical to the reflectance so that it will be suitable for single gamma driving. Detailed electro-optic performances, such as voltage-dependent light efficiency and viewing angle of the proposed device configuration, are investigated.

• Proceedings of the Optical Society of Korea Conference
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• 2009.02a
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• pp.549-550
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• 2009

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.6
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• pp.501-509
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• 2003

We have designed transflective liquid crystal display(LCD) associated with in-plane switching of a LC director driven by fringe-field, unlike other LCD mode. Reflective area consists of a λ/2 compensation film and a LC cell with retardation value(dΔn) of λ/4 with their optic axes making an angle of 15$^{\circ}$ and 75$^{\circ}$ against polarizer, respectively. In the transmissive area, top and bottom polarizers are parallel each other, an LC has a dΔn of λ/2, and another λ/2 compensation film is inserted between the LC cell and bottom polarizer. With the configuration, both devices show dark state initially. When an incident light is 550nm, the device shows wide-viewing-angle characteristics such that in the reflective area the contrast ratio target than 5 exists up to 55$^{\circ}$ of polar angle in all directions and in transmissive area it exists about 100$^{\circ}$ in vortical direction and 110$^{\circ}$ in horizontal direction.