Multi-Touch Sensing Technology for Large-Sized Displays

摘要

This study presents the description and implementation of a multi-touch screen technology that can be used in touch monitors, smart televisions, public information devices, digital signage, etc. Owing to the soft and natural feel of a finger touch, the projected capacitive touch is the most popular technology in small devices. For large-sized applications, devices can interface with multiple users who use the fingers, stylus, gloved hands, or other objects. Various sources of input can be supported by using the infrared optical imaging touch solution that is described in this study. In order to integrate the multi-touch function with a Liquid Crystal Display, the panel of a typical Liquid Crystal Display is modified to include only infrared light units and infrared image detection units. The objects that touch a display are recognized by the infrared image detection units by using digital image processing, and the touch positions are calculated by using a triangulation method. The multi-touch Liquid Crystal Display also detects the touched area and human gestures. This optical touch technology is used to create 21.5 in., 52 in., and 84 in. displays. A 21.5 in. multi-touch monitor is implemented for commercial mass production. Thus, a scalable touch detection technology that uses infrared light units with few Light Emitting Diodes and infrared image detection units with an image sensor, and the algorithm that is used to calculate the touch positions with a high degree of accuracy are presented.