Won-Tae Choi

10-bit Driver IC Using 3-bit DAC Embedded Operational Amplifier for Spatial Optical Modulators (SOMs)

A 10-bit driver IC for laser projection full high-definition TV (HDTV) applications using a spatial optical modulator (SOM) has been developed. For high-speed data transfer between the timing controller and driver IC, the driver IC adopts a mini-LVDS interface that operates up to 400 Mbps. To reduce the chip area, a digital-to-analog converter (DAC) structure including a 7-bit resistor-string DAC and a unity-gain buffer, which has a 3-bit linear DAC, is proposed. The area of the proposed DAC is 40% smaller than that of the typical 8-bit resistor-string DAC. The driver IC, which has 546 channels, is fabricated using a 0.35-mum CMOS process, and its area is 21 700 mum times 3 000 mum. The measured INL and DNL of the output voltages are less than 0.13 LSB, and the settling time is 1.93 mus with 40 pF capacitive loads. The output voltage deviation of the driver IC is achieved as 1.3 mV by compensating the nonuniformity among output channels.

A 10b Driver IC for a Spatial Optical Modulator for Full HDTV Applications

A 10b driver IC for laser projection full HDTV applications uses a 7b resistor-string DAC and a unity-gain buffer with a 3b DAC. The driver has 546 output channels, output voltage deviation of less than 1mV, a 200MHz mini-LVDS interface, and a maximum settling time of 2.4 mus for a 1080pixel spatial optical modulator with 40pF capacitive loads. The IC is fabricated in a 0.35 mum CMOS process and the chip area is 21.7 times3.0 mm2

A New Approach to Color Adjustment for Mobile Application Displays with a Skin Protection Algorithm on a CIE1931 Diagram

Mobile displays use liquid crystal displays (LCDs). Such displays have various problems, such as narrow color gamut and color saturation. We propose an algorithm to solve these problems by using data processing without panel replacement. In general, the subtle problems in color adjustment are skin color conversion and color saturation. The human skin tone is the color that is typically remembered; viewers feel awkward when skin colors are converted to unnatural colors. This paper proposes as a solution a skin protection algorithm that detects human skin colors and protects skin colors from changing. It also introduces adaptive quadratic curves that reproduce natural appearances more vividly without color saturation. In addition, the system does not use field-to-field processing but pixel-to-pixel processing in real time so that the incoming image can be displayed without field flickering

Color image enhancement method using a space-variant luminance map

This paper presents a method for improving the contrast of color images. A variable and nonlinear gamma characteristic is applied to the input image, depending on the local dependency of the intensity. In this work, we present a local contrast correction algorithm that allows for simultaneous low-light region and high-light region adjustments, based on simple pixel-wise gamma correction. Also, to minimize the change in color saturation between the input and the output image, we present the applied local characteristic.