Tae-Seok Jang

A Novel Two-Dimensional Adaptive Dimming Technique of X-Y Channel Drivers for LED Backlight System in LCD TVs

In this paper, a novel two-dimensional (2-D) adaptive dimming technique with X-Y channels for light-emitting diode (LED) backlight system in LCD TVs is proposed. The proposed LED backlight has matrix-structured LED modules with row and column switches to control the brightness of individual division block. It shows local dimming effects such as reduced power consumption and high dynamic contrast ratio even with much less number of LED drivers than that of the conventional 2-D local dimming method. Therefore, low cost and compact design of LED drivers can be achieved. This paper also contains a new adaptive dimming algorithm and image manipulation technique for the proposed LED backlight system. The proposed dimming technique is verified by simulation and experimental results based on a RGB-LED backlight of a 32-in LCD TV.

64.4: Smart Algorithms for Local Dimming LED Backlight

To reduce power consumption and improve image quality including contrast ratio and color gamut, LED backlight units (BLUs) consisting of many small blocks in 2-dimensional space are implemented. Either white-gray-level luminance or color is controlled by the local dimming LED BLU. However, such a BLU can induce various recognizable artifacts. A method is proposed for exact block luminance calculation along with a new algorithm to correct local dimming artifacts. A new concept of color classes has also been developed to achieve extremely wide color gamut and to minimize color related artifacts.

A novel adaptive dimming technique with X-Y channels for LED backlight system of LCD TVs

A novel adaptive dimming technique with X-Y channels for light emitting diode (LED) backlight system of LCD TVs is proposed. It has matrix structured LED modules with row and column switches to control the brightness of individual division block. It shows local dimming effects such as reduced power consumption and high dynamic contrast ratio with even using much fewer number of LED drivers of proposed method than that of conventional local dimming method. Therefore, low cost and compact design of LED drivers can be achieved. This paper also contains a new adaptive dimming algorithm and image compensation technique for proposed system.

48.4: Invited Paper: Adaptive Luminance and Power Control (ALPC) for LED Backlight Units

Adaptive luminance and power control is proposed for LCD-TVs with LED backlight units to provide several advanced features compared to conventional local dimming LED backlights. with ALPC, the luminance of a bright image on the display increases as the size of the bright image decreases, resulting in higher image quality that is more comfortable to end users. A 46” FHD LCD-TV equipped with an ALPC LED backlight achieved peak luminance of 500 nits and a contrast ratio of 100,000:1 with 30% fewer LEDs and maximum power consumption of 100W.

New Cell Structure with Edge-thick Tunnel Oxide for Highly Reliable NAND Flash Memory Devices

One of the most important performances of NAND flash memory is reliability characteristics, such as program/erase cycling and data retention. Tunnel oxide quality is essential to the reliability and it is well known that tunnel oxide degradation during FN (Fowler-Nordheim) stress is due to the oxide trap and interface trap generation. It is believed that trapping mainly occurs where tunnel oxide is locally thin. For example, conventional SAP (self-aligned poly) process with shallow trench isolation, tunnel oxide at active edge is necessarily thinner than active channel. In this paper, we proposed a new process scheme to fabricate optimized tunnel oxide thickness varying from active center to edge, and we confirmed the improvement of reliability characteristics such as Vth shift and interface trap density during endurance cycling