All optical gesture, touch and pressure sensing
Applied Sciences undertook a project to determine if a compact all-optical system could be designed that would sense gesture and multi-touch.
This project was undertaken at a time before the industry standardized on projective capacitive touch screens.
The aim was to construct a system that used imaging optical lightguide technology both to provide the backlight for an LCD, and allow imaging through it, both on and off screen.
Two wavelengths of infra-red were utilized in a time-sequential display and imaging system. Nearly a decade later, this remains a unique device.
A detailed description of the system is provided here: All optical interactive display