OPTICAL COUPLING IN TOUCH-SENSING SYSTEMS

摘要

A touch-sensitive apparatus operates by light frustration (FTIR) and comprises a light transmissive panel (1) with a front surface (5) and a rear surface (6). Light emitters (2) are optically coupled to the panel (1) at entry ports along a periphery region of the panel (1), and light detectors (3) are optically coupled to the panel (1) at exit ports along the periphery region for detecting light transmitted inside the panel (1). At least one optical sheet (20) is provided on the rear surface (6) in the periphery region. In an outcoupling installation, the light detectors (3) are arranged at the respective optical sheet (20) to receive, on a respective light-sensitive surface (3A); light from the optical sheet (20), and each light detector (3) is arranged with the light-sensitive surface (3A) essentially perpendicular to the rear surface (6). In an incoupling installation, each light emitter (2) is arranged at the respective optical sheet (20) to emit diverging light with a main direction that is essentially parallel to the rear surface (6) such that a portion of the diverging light impinges on the optical sheet (20) so as to define a respective entry port.

主权项

1. A touch-sensitive apparatus, comprising:
a light transmissive panel that defines a front surface and an opposite, rear surface, the light transmissive panel comprising a center region and a periphery region adjacent to the center region; light emitters which are optically coupled to the panel at entry ports along the periphery region so as to generate individual beams of light that diverge in the plane of the panel while they propagate inside the panel, from the entry ports and into the center region), by internal reflections between the front and rear surfaces; and light detectors which are optically coupled to the panel for detecting light transmitted inside the panel at exit ports along the periphery region; wherein at least one sheet-like optical element is provided on the rear surface in the periphery region; wherein the light detectors are arranged at said at least one sheet-like optical element to receive, on a respective light-sensitive surface, light from the at least one sheet-like optical element; and wherein each of the light detectors is arranged with the light-sensitive surface essentially perpendicular to the rear surface.