Jih-Fon Huang

P‐102: Hysteresis Suppression of Thin‐Film Transistors with Poly (Vinyl Alcohol) Insulator on Flexible Stainless Steel Substrate

The Hysteresis effects can be suppressed in flexible thin-film transistors with poly (vinyl alcohol) insulator without crosslinking agent. The characteristic of hysteresis was greatly reduced by SiO2 nano-particle in PVA solution. The TFTs were fabricated by using a-IGZO as active layer at room temperature. The TFTs exhibited stable performance with field effect mobility (∼10.81 Vs/cm2), high on/off current ratios (∼106), and low threshold voltage (∼−1V) on planarized stainless steel substrate. The transfer curve which measured from various sweep ranges in two different sweep directions suggested that the hysteresis has been successfully suppressed.

Bilateral filtering and adaptive tone-mapping for qualified edge and image enhancement

Most of high-contrast images are common with dark and bright area. It is difficult to present the detail on both dark and high light areas on display devices. In order to resolve this problem, we proposed a method of image enhancement to improve this image quality and used bilateral filter to keep the detail. In paper, we applied an appropriate algorithm to process images. At first, we use bilateral filter to separate image. One is large scale image and the other is detail image. Second, we made large scale image which was translated into histogram. In order to make the images divided into three stairs, such as lightness, middle-tone and darkness region. We decided two optimal threshold parameters. Finally, according to three images we use different tone-mapping method to process each stair. The tone-mapping method includes adaptive s-curve and gamma curve algorithms. The experiment results of this study revealed image detail and enhancement. To avoid contour phenomenon is in lightness region.

A novel driving method and device to reduce color breakup in color‐sequential displays

— Color-sequential displays offer a better luminous efficiency, a higher spatial resolution, and a lower cost than conventional displays. However, a common problem is that visual effects cause color edge-blurring of a moving picture, a phenomenon called color breakup or rainbow effects. Most driving methods, such as increasing the frame rate and inserting a black/white frame or another color sub-frame to reduce the color breakup in color sequential displays has been presented in many papers, but every method has some limitations and problems. An innovative driving method and device to reduce the color-breakup phenomenon will be demonstrated in this paper, designed without increasing the driving frequency. Instead, the brightness is increased by one third at the very least. Our method divides the driving frequency into four sub-frames (WRGB), which is operated at 180 Hz compared to 240 Hz for conventional driving. Our result shows that the image quality is improved. The color-breakup simulation based on “eye trace integration” and compensated white light will also be presented in this paper.

P-113: Color Management for Multiple-Primary Flexible Cholesteric-LCD

The reflective cholesteric liquid crystal display suffers from voltage-induced color shift and viewing angle-dependent color shift. In this paper, three solutions are presented to overcome these problems. First, four types of cholesteric liquid crystals were prepared and characterized to find the best mixture with the lowest voltage-induced color shift and reflectance reduction. Secondly, 5-primary (red, yellow, green, cyan and blue) cholesteric liquid crystals were prepared such that the color gamut and reflectance were enhanced. Finally, the viewing angle-dependent color shift was characterized and then compensated by adjusting their chromaticity by using red/green/blue LED light sources.

P-74: Automatic Parameters Measurement System for Testing of Bistable Cholesteric Liquid Crystal Displays with Three Different Driving Sequence Methods and Application of Gray-Level Switching

In this study we have designed an electro-optical measurement system for bistable cholesteric liquid crystal displays which can provide variable drive schemes and measure a series of characteristic curves automatically. The three driving sequence measurement methods for cholesteric liquid crystal displays (CHLCDs) are discussed: conventional driving sequence measurement, cumulative driving sequence(CDS) measurement and dynamic driving sequence(DDS)measurement. Then we implement greyscale application of bistable cholesteric liquid crystal displays by the different driving sequence measurement results.

75.5: Evaluating Procedure of Color Rendering Property on Reflective LCD

An evaluating procedure was introduced and demonstrated to reveal the impact of color appearance induced by ambient illumination for reflective-type LCDs. The concepts of Color Rendering Index and Color Quality Scale were cooperated to account for the differences of color rendering between LED lightings with identical correlated color temperature but various spectra. The results showed that the colorimetric performance of reflective LCD was strongly dependent on various LED spectra and light level. And the proposed assessments, CRI and CQS, can effectively describe how well LED lighting renders the reflective-type LCD.