• 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)

• Proceedings of the Optical Society of Korea Conference
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• 2001.02a
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• pp.268-269
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• 2001

반사형 액정표시장치는 저전력 휴대용 표시장치 시장이 급격하게 성장함에 따라 큰 주목을 받고 있다. 현재 반사형 액정표시장치는 밝기면에서 우수한 특성을 갖는 mixed mode TN(MTN)과 reflective TR(RTN)과 같은 단일편광자를 이용한 액정모드를 기본적으로 사용하고 있다. 그러나, 이러한 액정모드는 이중편광자를 이용한 액정모드와 비교해서 dark 상태에서 누설광이 많이 발생하여 대비비가 저하되는 단점이 있다. (중략)

• Journal of the Optical Society of Korea
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• v.16 no.4
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• pp.354-364
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• 2012

In this paper, a new 2-step quadrature phase-shifting digital holographic optical encryption method using orthogonal polarization is proposed and tolerance errors for this method are analyzed. Unlike the conventional technique using a PZT mirror, the proposed optical setup comprises two input and output polarizers, and one ${\lambda}$/4-plate retarder. This method makes it easier to get a phase shift of ${\pi}$/2 without using a mechanically driven PZT device for phase-shifting and it simplifies the 2-step phase-shifting Mach-Zehnder interferometer setup for optical encryption. The decryption performance and tolerance error analysis for the proposed method are presented. Computer experiments show that the proposed method is an alternate candidate for 2-step quadrature phase-shifting digital holographic optical encryption applications.

• Current Optics and Photonics
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• v.2 no.3
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• pp.286-290
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• 2018

We investigated the dependence of the retardation dispersion on the polarization direction of ultraviolet (UV) light during the photopolymerization of self-organized smectic reactive mesogen (RM) molecules. RM retarder film that was photopolymerized with UV light linearly polarized parallel to the layer plane showed negative dispersion (ND) of retardation for a wide range of UV polymerization temperatures. On the other hand, film that was photopolymerized with unpolarized UV light showed negative dispersion in a narrow range of UV polymerization temperatures. With a certain UV polymerization temperature, the dispersion of retardation was converted from positive to negative, depending on the UV polarization.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.8 no.4
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• pp.139-144
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• 1983

In this paper, the ploarization and Faraday rotation properties of the single mode optical fiber have been investigated for magnto-optic current transformer application. On the analysis, the optical fiber is modeled as a linear retarder and the intrinsic birefreingence of the optical fiber is approximately found to be 2.57'/m from the measurement, and the bend-induced birefringence is proportional to the inverse square of bending radius. The polarization rotation sensitivity is foung to be F/H=1.4x$10^-5$rad/[A/m] from the analysis of Faraday rotation of single mode optical fiber.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.7 no.4
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• pp.161-166
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• 1982

In this paper, the intrinsic birefringence and twist-induced rotation of the single mode optical fiber have been investigated. On the analysis, the optical fiber has been modeled as a linear retarder and the intrinsic linear retardation of the single mode optical fiber is approximately found to be 2.57'/m from the measurement. Theoretically analyzing the twist-induce rotation by the purturbation theory, it is found that the magnitude of the twist-induced rotation varies linearly with the twisted angle. And this theorerical result has been in good accord with the experimental result.

• Journal of Information Display
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• v.12 no.1
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• pp.11-15
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• 2011

An inverse-twisted-nematic (ITN) transflective (TRF) liquid crystal (LC) display, where two imprinted optical films (IOFs) with surface microstructures are embedded was developed. One of the IOFs serves as an in-cell patterned retarder with multioptic axes, and the other behaves as a viewing-angle enhancement film. In the presence of an applied voltage, the surface microstructures on the IOFs provide the spontaneous twist of the LC from a vertically aligned state to a $90^{\circ}$ twisted-nematic (TN) state in the transmissive part, and to a $45^{\circ}$ TN state in the reflective part. The developed ITN TRF LC display exhibits high transmission and reflectance, fast response, and wide-viewing characteristics, along with achromaticity.

• Korean Journal of Optics and Photonics
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• v.25 no.3
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• pp.150-154
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• 2014

The conditions under which a composite retarder consisting of two different retardation plates can be operated as a tunable quarter-wave plate are derived. The explicit expressions for the azimuthal angle of a linear polarizer and those of two retardation plates to generate circularly polarized light are presented as a function of retardation angles. Those expressions for the azimuthal angles derived using the Jones matrix formalism are verified as identical to the expressions derived from the analysis of the trajectory on a Poincar$\acute{e}$ sphere. A couple of examples are presented for generating circularly polarized light when two identical retardation plates are used.

• Journal of Information Display
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• v.5 no.2
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• pp.23-26
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• 2004

For high end, large area displays, all current LC modes require some degree of optical compensation to improve the front of screen viewing experience. Currently most optical films are laminated to the outside of the LCD cell, between the glass and polariser. In this paper we wish to show how it is possible to integrate the compensating optical film within a VA mode LCD cell. The paper will describe the process of making the biaxial film through the process of in-situ photopolymerisation of an aligned film of reactive mesogens in the cholesteric phase using polarised UV light. The film can be made on the colour filter array side of the LCD panel. In addition the process of fabricating a VA mode LCD containing this film will be described and the performance of this module will be presented.

• Korean Journal of Optics and Photonics
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• v.23 no.6
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• pp.274-280
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• 2012

A normal incidence ellipsometer is fabricated to measure the optical anisotropy of a small spot whose diameter is less than $8.0{\mu}m$, by adding a beam splitter and a prism to the conventional rotating analyzer type ellipsometer. The polarizing actions of the added optical components are calibrated to improve the accuracy of the anisotropy measurement. The standard deviation of the optical anisotropy factor decreased to 0.00083, and the variation of the optical anisotropy factor of rutile versus sample azimuth angle variation also decreased to 0.015, after adoption of a non-polarizing beam splitter and a quarter wavelength phase retarder, followed by removal of the optical fiber and a careful choice of measurement wavelength.