Showing papers by "Seung Hee Lee published in 2001"
Patent•
10 Oct 2001
TL;DR: In this paper, a fringe field switching mode LCD is proposed, which consists of a first and a second transparent insulating substrate arranged opposite to each other with a predetermined distance, with a liquid crystal layer including a plurality of liquid crystal molecules interposed between them.
Abstract: Disclosed is a fringe field switching mode LCD. The disclosed comprises a first and a second transparent insulating substrates arranged opposite to each other with a predetermined distance, with a liquid crystal layer including a plurality of liquid crystal molecules interposed between them; a plurality of gate bus lines and data bus lines formed on the first transparent insulating substrate and arranged in a matrix form to define a unit pixel; a thin film transistor formed at the intersection of the gate bus line and the data bus line; a counter electrode disposed in each unit pixel, made of transparent conductor; and a pixel electrode arranged in each unit pixel to generate a fringe field with the counter electrode, being insulated with the counter electrode and made of transparent conductor and including a plurality of upper slits and lower slits symmetrical each other with respect to long side of the pixel with a predetermined tilted angle.
144 citations
TL;DR: The product issues of existing LC devices related to manufacturing process and performance are discussed and several TFT-LCD devices exhibiting high image quality are developed and commercialized.
Abstract: Several TFT-LCD devices exhibiting high image quality have been developed and commercialized, overcoming the narrow viewing-angle characteristics of conventional twisted-nematic (TN) devices. Nevertheless, no single device dominates large-sized TFT-LCDs. In this paper, the product issues of existing LC devices related to manufacturing process and performance are discussed.
32 citations
Journal Article•
TL;DR: In this article, a nematic liquid crystal (LC) cell associated with the transition of the liquid crystal director from a twist to a twisted bend alignment was fabricated, where an initial transition voltage is not required unlike in the case of the conventional optically compensated bend (OCB) cell.
Abstract: We have fabricated a nematic liquid crystal (LC) cell associated with the transition of the liquid crystal director from a twist to a twisted bend alignment, where an initial transition voltage is not required unlike in the case of the conventional optically compensated bend (OCB) cell. For the device which is initially in the twist state, the molecular deformation occurs continuously from twist to bend alignment without forming nucleations with increasing voltage and initial setting voltage for transition. The device exhibits a wide viewing angle with compensated films and a fast response time of less than 10 ms.
23 citations
TL;DR: In this article, a novel reflective nematic liquid-crystal cell driven by a fringe field was fabricated, which exhibits a wide viewing angle intrinsically owing to the in-plane rotation of the liquidcrystal director.
Abstract: We have fabricated a novel reflective nematic liquid-crystal cell driven by a fringe field. In the absence of an electric field, the liquid-crystal molecule is homogeneously aligned and when a fringe field induced by interdigital electrodes is applied, liquid-crystal molecules rotate in plane in the entire whole area. A conventional in-plane switching (IPS) cell was impossible for application to a reflective system due to its low aperture ratio. However, a newly designed fringe-field switching (FFS) cell is possible due to its high transmittance. Furthermore it exhibits a wide viewing angle intrinsically owing to the in-plane rotation of the liquid-crystal director. Several reflective systems with either two polarizers or one polarizer with a quarter-wave retardation film are possible. In this study, we investigate the switching principle of each system and compare their electrooptic characteristics by simulation and experiment.
12 citations
TL;DR: In this paper, a hybrid aligned liquid crystal (LC) cell with negative dielectric anisotropy of the nematic LC driven by fringe field was proposed, which is normally black mode.
Abstract: We propose a novel hybrid aligned liquid crystal (LC) cell with negative dielectric anisotropy of the nematic LC driven by fringe field, which is normally black mode. In the on-state, the dielectric torque between the LC director and horizontal component of the fringe field causes the LC director to rotate in the entire area, so that the cell appears to be white. The device, with a wedge-shaped pixel electrode and optical compensation film, also shows a wide viewing angle, high light efficiency and low driving voltage.
11 citations
TL;DR: In this article, the hole blocking layer (HBL), BCP [2,9-dimethyl-4,7-diphenyl- 1,10-phenanthroline] was used to improve the electrical and optical properties of the Eu complex.
Abstract: The Eu complex, Eu(TTA)3(TPPO) [tris-(4,4,4-trifluoro-1-(2-thienyl)-butane-1,3-dionate)-triphenyl phosphine oxide europium(III)] is known as the sharp red electroluminescent organic material at the wavelength of 615nm, but its luminance is quite low. In this study, we improved it's electrical and optical characteristics using the hole blocking layer (HBL), BCP [2,9-dimethyl-4,7-diphenyl- 1,10-phenanthroline]. The device with a structure of ITO/TPD/Eu(TTA)3(TPPO)/BCP/Alq3/Li:Al/Al was fabricated and its photouminescent and electroluminescent characteristics were investigated. It was found that the BCP layer with a thickness of 6nm can block the holes from Eu complex efficiently to improve the EL characteristics of the device. Details on the electrical properties of these structures will be also discussed.
3 citations
TL;DR: In this paper, a new vertical alignment display driven by fringe field with initially biased surface boundary condition on one side of substrate is presented, which exhibits interesting molecular dynamics depending on biased state when the voltage is applied.
Abstract: Vertical alignment display is of interest in a view point of fast response time with wide viewing angle and rubbing free displays. We have fabricated a new vertical alignment display driven by fringe field with initially biased surface boundary condition on one side of substrate. The device exhibits interesting molecular dynamics depending on biased state when the voltage is applied. In this paper, the electro-optic characteristics and molecular dynamics of novel cells will be discussed.
1 citations