• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.171-171
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• 2010

Electro-optic characteristics of liquid crystal display using fringe field switching(FFS) device depend on many parameters such as cell retardation, electrode structure, rubbing angle, cell gap and dielectric anisotropy. In this paper, the light efficiency of FFS mode will be analyzed to confirm the electro-optic characteristics according to positive dielectric anisotropy such as transmittance, operating voltage and response time.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.173-173
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• 2010

We proposed viewing angle switchable liquid crystal display(LCD) associated with fringe-field switching (FFS) mode with high aperture ratio characteristic. In the device, single pixel is separated into two regions, named as main pixel for displaying images and sub pixel for viewing angle control. In sub pixel region, add the common electrode on the top substrate and the initial alignment of liquid crystal is Hybrid Alignment Nematic (HAN) state. In conclusion, we suggested that the device has high aperture ratio characteristic because the LC directors are rotated in which viewing angle control region are generated fringe electric field.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.560-563
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• 2007

The light efficiency of fringe-field switching (FFS) mode was found to be dependent on the magnitude of dielectric anisotropy, indicating that the voltagedependent maximal effective cell retardation value in the on state is a function of magnitude of the dielectric anisotropy of the LC.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.556-559
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• 2007

Effects of carbon nanotube (CNT) on the in-plain switching (IPS) and fringe-field switching (FFS) modes were investigated. The studies show that the CNT-doped LC cells exhibit lower transmittance but faster response time than those in the pure LC cell. Interestingly, the CNT-doped IPS and FFS modes show different characteristic in effects of operating voltage.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.3
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• pp.224-230
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• 2003

The voltage-dependent transmittance curve of a homogeneously aligned liquid crystal (LC) cell driven by fringe-electric field(named FFS mode) was studied, while changing dielectric anisotropy of a LC. The results show that for a LC with positive dielectric anisotropy while positioning at initial position. Therefore, we conclude that the dynamic stability is strongly dependent on the types of the LCs and voltage-dependent dynamics of the LC with negative dielectric anisotropy is staler than that of the LC with positive dielectric anisotropy in the FFS mode.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.8
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• pp.1282-1289
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• 1989

Dual field speckle interferometry that is sensitive to the surface displacement of the object is constructed, and fringe patterns that have the displacement-informations are analysed using digital image processing. From 10\ulcorner to 80\ulcorner with respect to each specklegrams are obtained by double-exposure techniques, which are analysed by the proposed system and algorithm. Up to 10\ulcorner displacement, near measurable lower bound of Speckle Interferometry, fringe visibility is decreased due to decreasing fringe density, therefore relative errors are produced over 10% but over that displacement, relative errors are produced below 5%. Particularly, it is observed that spatial frequencies of each displacement are comparatively linear.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.621-624
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• 2006

Pixel structure of the fringe-field switching (FFS) mode to improve transmittance has been studied. New FFS structures related to the electrode structure at the edges of pixel, and the pixel electrode width and distance between electrodes was optimized. The former improves transmittance by minimizing the region of disclination lines. The latter improves it by increasing light efficiency above center of electrodes and also response time.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1386-1389
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• 2008

Conventional viewing angle switching electrode requires pixel division and additional liquid crystal panel. Hence the conventional viewing angle switching has low aperture ratio and high thickness. In this paper we proposed new viewing angle switching using hybrid aligned nematic mode by fringe-field electrode field (named HAN-FFS) with single liquid crystal panel. The fringe-field switching electrode is located at the bottom, and the additional common electrode is located at the top of the cell to control viewing angle. The proposed device is free from additional liquid crystal panel and pixel division. Consequently, the suggested structure has not only high aperture ratio but also show an excellent potential for viewing angle switching.

• Journal of the Korean Society for Nondestructive Testing
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• v.29 no.6
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• pp.557-562
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• 2009

Abrupt change of cross-section in mechanical parts is one of significant causes of structural fracture. In this paper, a hybrid method is employed to analyze the stress distribution of a discontinuous plate. The plate with an inclined crack is utilized in our experiment and the stress field in the vicinity of crack tip is calculated through isochromatic fringe order of given points. This calculation can be made handy through least-squares method integrated with complex power series representation(Laurent series) implemented on a computer program for high-speed processing. In order to accurately compare calculated results with experimental ones, both of actual and regenerated photoelastic fringe patterns are doubled and sharpened by digital image processing. The experiment results show that regenerated patterns obtained by hybrid method are quite comparable to actual patterns.

• Journal of the Korean Society for Nondestructive Testing
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• v.27 no.6
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• pp.550-555
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• 2007

Stress intensity factor is one of the most important parameters in fracture mechanics. Both the stress field distribution and the crack propagation are closely related to these parameters. Due to the complexity of actual engineering problems, it is difficult to calculate the stress intensity factor by theoretical formulation, so photoelasticity method is a good choice. In this paper, modified two parameter method is employed to calculate stress intensity factor for opening mode by using data from more than one photoelastic fringe loop. For getting accurate experiment results, the initial fringes are doubled and sharpened by digital image programs from the fringe patterns obtained by a CCD camera. Photoelastic results are compared with those obtained by the use of empirical equation and FEM. Good agreement shows that the methods utilized in experiments are considerably reliable. The photoelastic experiment can be used for bench mark in theoretical study and other experiments.