Integrated Ambient Light Sensor with an LTPS Noise-Robust Circuit and a-Si Photodiodes for AMLCDs

スポンサーリンク

概要

• 論文の詳細を見る

• Ambient light sensors have been used to reduce power consumption of Active Matrix Liquid Crystal Displays (AMLCD) adjusting display brightness depending on ambient illumination. Discrete sensors have been commonly used for this purpose. They make module design complex. Therefore it has been required to integrate the sensors on the display panels for solving the issue. So far, many kinds of integrated sensors have been developed using Amorphous Silicon (a-Si) technology or Low Temperature Polycrystalline Silicon (LTPS) technology. These conventional integrated sensors have two problems. One is that LTPS sensors have less dynamic range due to the less photosensitivity of LTPS photodiodes. The other is that both the LTPS and a-Si sensors are susceptible to display driving noises. In this paper, we introduce a novel integrated sensor using both LTPS and a-Si technologies, which can solve these problems. It consists of vertical a-Si Schottky photodiodes and an LTPS differential converter circuit. The a-Si photodiodes have much higher photosensitivity than LTPS ones, and this contributes to wide dynamic range and high accuracy. The LTPS differential converter circuit converts photocurrent of the photodiodes to a robust digital signal. In addition it has a function of canceling the influences of the display driving noises. With the circuit, the sensor can stably and accurately work even under the noises. The performance of the sensor introduced in this paper was measured to verify the advantages of the novel design. The measurement result showed that it worked in a wide ambient illuminance range of 5-55, 000lux with small errors of below 5%. It was also verified that it stably and accurately worked even under the display driving noise. Thus the sensor introduced in this paper achieved the wide dynamic range and noise robustness.

• 2010-11-01

著者

• AYRES J.

  Philips Research Laboratories

• Sano Keiichi

  Chimei Innolux Corp.

• Hsueh Fu-yuan

  Chimei Innolux Corp.

• MATSUKI Fumirou

  TPO Displays Corp.

• HASHIMOTO Kazuyuki

  TPO Displays Corp.

• KAKKAD Ramesh

  Chimei Innolux Corp.

• CHANG Wen-Sheng

  Chimei Innolux Corp.

• EDWARDS Martin

  Philips Research

• YOUNG Nigel

  Philips Research

• Ayres J.

  Philips Research

関連論文

• Numerical Analysis of the Electrical Characteristics of Gate Overlapped Lightly Doped Drain Polysilicon Thin Film Transistors
• Analysis of Drain Field and Hot Carrier Stability of Poly-Si Thin Film Transistors
• Differentiation of Effects due to Grain and Grain Boundary Traps in Laser Annealed Poly-Si Thin Film Transistors
• Differentiation of Effects Due to Grain and Grain Boundary Traps in Laser Annealed Poly-Si Thin Film Transistors
• Integrated Ambient Light Sensor with an LTPS Noise-Robust Circuit and a-Si Photodiodes for AMLCDs

スポンサーリンク