Scanning FTIR systems for touch detection

摘要

A touch-sensitive apparatus operates by FTIR (Frustrated Total Internal Reflection) to detect touches on a surface of a light transmissive panel. An illumination arrangement is controlled to propagate light by internal reflection from an elongated incoupling site on the panel to an elongated outcoupling site on the panel, and a detection arrangement is controlled to detect light reaching the outcoupling site. The illumination arrangement is controlled to sweep a first set of individual beams of light along different subsets of the incoupling site to generate a full beam sweep along the incoupling site. Thereby, the individual beams are be controlled to generate a “sub-sweep” of the incoupling site, which enables a compact design of the illumination arrangement and/or use of comparatively simple sweep generating devices and/or identical re-direction components in the illumination arrangement.

主权项

1. A touch-sensitive apparatus, comprising:
a light transmissive panel that defines a touch surface and an opposite surface; an illumination arrangement for propagating light by internal reflection between the touch surface and the opposite surface from an elongated incoupling site on the panel to an elongated outcoupling site on the panel; and a detection arrangement for detecting light reaching the elongated outcoupling site; wherein the illumination arrangement is configured to sweep each individual beam of light in a first set of individual beams of light along a spatially different portion of the elongated incoupling site to generate a full beam sweep along the elongated incoupling site.