This paper proposes a vertical alignment cell based on a negative anisotropy nematic liquid crystal doped with pentacene. The device shows a lower operating voltage and faster dynamic response time compared to a vertical alignment cell without pentacene. The dielectric anisotropy, elastic constant and rotational viscosity of the pentacene-doped liquid crystal have been measured, and the results show that the low operating voltage and fast response time of the pentacene-doped vertical alignment cell is due to the increase of dielectric anisotropy and the decrease of rotational viscosity. Also, the frequency dependent dielectric relaxations of both the normal and the pentacene-doped nematic liquid crystal have been measured. As the result, it is shown that the pentacene lowers the dielectric response, which in turn reduces the rotational viscosity.

We propose a polarization switching device using optically compensated pi cell for polarization-glass-type three-dimensional display. This device shows good optical properties such as high transmittance and low cross-talk ratio because of its fast dynamic response characteristics. To improve the brightness and contrast ratio on the right-and left-hand sides, we attach optical retardation films on each side of the polarization glasses instead of attaching the films on the polarization switching panel. From the calculation and experiment, we obtain high contrast ratios, over 200:1, on both sides and a high brightness using only one film on each side. © 2011 American Institute of Physics. ͓doi:10.1063/1.3548863͔The flat-panel display technology has developed very fast in the past decade. Hence, this technology is attaining maturity and the market is approaching saturation. On the contrary, the market for three-dimensional ͑3D͒ display has been rapidly expanding worldwide. Many researchers have made various efforts to develop 3D displays with twodimensional ͑2D͒/3D switching, high brightness, and high resolution.1-9 Among these technologies, the stereoscopic 3D display using 3D glasses has attracted industrial attention because it has neither the loss of spatial resolution nor the 3D moiré effect between pixels and barrier. Moreover, the stereoscopic 3D technology is suitable for realizing 2D/3D switching easily. The glass-type 3D displays are divided into passive retarder type using patterned retarder film 5 and active retarder type using either liquid crystal ͑LC͒ shutter glasses 6,7 or polarization switching ͑PS͒ panels. 8,9 However, active retarder type with LC shutter glasses has poor brightness in the 3D mode because of the slow response time and writing speed of the LC panel and shutter glasses. Moreover, the shutter glass is too heavy and uncomfortable due to the presence of batteries, for an active operation. A 3D display with PS panel ͑3D-PS͒ uses polarization glasses that are lighter and more comfortable than LC shutter glasses, because they do not need batteries for operation. However, it also has drawbacks such as low brightness and 3D cross-talk because of slow response time of the PS panel.8 Moreover, without optical compensation, this device has low and asymmetric contrast ratio ͑CR͒. To overcome these limits, we suggested a 3D-PS using dual-frequency LC and two half-waveplate ͑HWP͒ films.9 However, it still has problems such as decrease in brightness due to the two HWPs, low CR under 200:1, and low cell gap under 3 m. Hence, it is difficult to commercialize this technology.In this letter, we propose a stereoscopic 3D display with a PS panel of high brightness and CR. The PS panel is a pi cell with very fast response time. To obtain high brightness and CR in the left-and right-hand sides simultaneously, we suggest a structure with optical compensation using one film on each side. We have measured the properties of the proposed cell, such as its electro-optical ͑EO͒ and dynamic response characteristic...

In this paper, we propose a new integrated gate driver circuit for random sensing operation of external compensated organic light‐emitting diode (OLED) display using oxide thin‐film transistor (TFT). Using this technology, we successfully launched 55‐inch and 65‐inch ultrahigh definition OLED TVs with gate in panel (GIP) circuit. The structure of the existing OLED TVs implemented gate signals through the gate integrated circuits (ICs) attached to the left and right sides of the panel. The structure using the gate IC was inferior to the panel structure using the GIP in terms of process and product design and cost. Thus, we propose a new oxide GIP circuit for OLED TV. Like the previous gate IC model, the proposed GIP circuit successfully implemented the random sensing function during the display operation. This GIP circuit is also designed to overcome the problems caused by the negative Vth characteristics of the oxide device.

We propose a new transflective liquid crystal display with two microlens arrays and a transflective plate. In this study, with a minimal transmission area on the transflective plate and using two microlens arrays, high light efficiency can be obtained for both the reflective and transmissive modes. In the transmissive mode, square-and cone-shaped microlens arrays are utilized to concentrate the light from a backlight unit. In the reflective mode, reflectance increases due to the enlarged reflective region. From the simulation results, compared with the conventional structure, the light efficiency increased to 97 and 80% in the transmissive and reflective modes, respectively.

We present a polarization-switching device with dual-frequency liquid crystal material for a stereoscopic three-dimensional (3D) display. This device shows good properties, such as low 3D cross talk and high brightness, due to a fast dynamic response time. Without optical compensation, however, this device has an asymmetric contrast ratio on the left- and right-hand sides of 3D glasses, because the viewing principles on both sides are different from each other. To solve this problem, we design an optical structure with two half-wave plate films using the Jones matrix method. As the results of simulation and experiment show, excellent dark states and high brightness are realized over the entire range of visible wavelengths on both sides.