OPTICAL-TOUCH TYPE INPUT DEVICE

摘要

PURPOSE: To provide a light touch type input device capable of more clearly distinguishing between an intended input from a light pen e.g. and the influence of peripheral light. CONSTITUTION: The input device is provided with active address specifying sensitive elements 18 for sensing a light input from the light pen, each element 18 is provided with a capacitor 25 to be periodically charged with the operation of a switch element 24, a discharging circuit including another switch device 27 connected to both the ends of the capacitor 25 and a light sensor 28, and when the device is driven, a light threshold characteristic appears by the discharging circuit. Thereby the capacitor 25 can distinguish an input from peripheral light in response to the sensitive element held at a prescribed intensity level or exposed to light more than the level. Each written pixel can be measured by detecting the charged state of its corresponding capacitor. The array of the sensitive elements is integrated on a matrix display device having sensitive elements 18 and display elements 12 loaded on a common supporting plate.