LIGHT GUIDE ASSEMBLY FOR OPTICAL TOUCH SENSING, AND METHOD FOR DETECTING A TOUCH

摘要

A light guide assembly (2) for use in a touch sensitive area (3) of an optical touch sensing device (1) for touch screens is configured to receive light, to allow the light thereby received to propagate in the light guide assembly, and to deliver the light thereby propagated in the light guide assembly further out of the light guide assembly. The light guide assembly comprises a plurality of light guide stripes (4, 5) for controlling the propagation of light. The optical touch sensing device is configured to detect the presence of an external object (10) on the basis of changes in the light delivered further out of the light guide assembly due to interaction of the light with the external object. According to the invention, the light guide assembly comprises an interaction arrangement (8, 9) configured to define at least one restricted interaction area (11) within the touch sensitive area for interaction between the light and the external object, the interaction arrangement comprising a two-way coupling arrangement (8, 9; 12; 14; 15) configured to couple light out of the light guide assembly, out of one light guide stripe (4), and to couple a portion of the thereby out-coupled light, after reflection from the external object (10), back to the light guide assembly into a second light guide stripe (5).

主权项

1. A light guide assembly for use in a touch sensitive area of an optical touch sensing device for touch screens, the light guide assembly being configured to receive light, to allow the light thereby received to propagate in the light guide assembly, and to deliver the light thereby propagated in the light guide assembly further out of the light guide assembly, the light guide assembly comprising a plurality of light guide stripes for controlling the propagation of light in the light guide assembly; the optical touch sensing device being configured to detect the presence of an external object on the basis of changes in the light delivered further out of the light guide assembly due to interaction of the light with the external object, wherein the light guide assembly comprises an interaction arrangement configured to define at least one restricted interaction area within the touch sensitive area for interaction between the light and the external object, the interaction arrangement comprising a two-way coupling arrangement configured to couple light out of the light guide assembly, out of one light guide stripe, and to couple a portion of the thereby out-coupled light, after reflection from the external object, back to the light guide assembly into a second light guide stripe, for detecting the presence of the external object on the basis of said reflection; wherein the first and the second light guide stripes are directed at an angle.