48.2: Display Architecture Suitable for Multiple Ambient Light‐Sensor Integration Using LTPS Technology

Abstract

We have developed a new LCD having multiple ambient light sensors (ALSs). Counters and a parallel-to-serial converter are formed in peripheral of the LCD panel, programmable clock drivers for the counters, and data registers to hold output of ALSs are included in a source driver LSI. The ALSs perform well in total showing nonlinear gamma property corresponding to the clock even for the case when one of the sensors is covered by a finger shadow.

47‐3: In‐Cell Ambient Light Sensors (ALSs) LCD Integration Using a‐Si TFT photo‐transistor and Four‐Mask Process Architecture Technology

“…On the other hand, the brightness can be tuned down automatically in a dark room for power saving by collecting signals from ambient light sensors. Optical sensors on thin-film-transistor liquid-crystal displays (TFT-LCDs) are primarily for optical touch panel, backlight control, and image acquisition [4][5][6]. Currently, value-added functions enabled by integrating photosensor in a-Si TFT and LTPS displays have been developed to incorporate functions, such as touch-input and peninput functions.…”

“…Display architecture with multiple ALSs integration is a solution to avoid the problem of false sensing. Ambient light false sensing problem with finger shadow occurs in case that a conventional discrete ALS display apparatus has only one light sensor [5][6]. Finger-shadow illuminance which the single-ALS sense differs from the actual illuminance even the sensitivity of photo-sensor performance is well.…”

In‐cell capacitive‐type touch sensor using LTPS TFT‐LCD technology

“…In addition, papers in the literature have reported technologies that incorporate additional functions into LCDs by integrating sensors with an ambient-light-sensing function, image-capturing function, pen/finger input function, and even a 3-D input function. [7][8][9][10][11] Among them, due to the recent increase in touch-screen-equipped displays, a great deal of attention has been paid to touch-sensor integration in LCDs (generally referred to as an "in-cell touch sensor") with expectations to improve image quality in thin and compact structures of appliances. [12][13][14][15] LCD-embedded-type sensors, on-cell-type sensors, charge-sensing sensors (pressed capacitive type), and lightsensing sensors (non-pressed type) have been reported, and their pros and cons 16,17 are summarized in Table 1.…”