Toshiba Matsushita Display Technology Co., Ltd. (TMD) has developed an LCD panel that enables finger-touch input using photosensors under a range of light conditions from dark indoor to bright outdoor. Through enhanced sensitivity of the photosensors integrated onto the LCD panel's glass substrate and optimized signal processing functions, the panel detects reflection from a finger using backlight in dark indoor and finger shadows using external light in bright outdoor.
The prototyped panel is a transmissive LCD panel using a 2.8-inch (7.1 cm diagonal) WQVGA (400 x 240 pixels) resolution, low-temperature polycrystalline Si (p-Si) TFT with approximately 65,000 display colors. The range of ambient light intensity, in which finger-touch input is available, extends from 0 to 100,000 lx. The panel has become able to recognize finger-touch input in a wide range of light intensity by switching its recognition modes between finger shadows using external light and finger reflections using its built-in backlight depending on the situation. The panel not only recognizes finger shadows but also supports input using an optic pen. TMD will present this panel at the Flat Panel Display International (Display 2007) show to be held at Tokyo Big Sight from April 11 to 13.