| 摘要 |
An apparatus is operated to determine the location of at least one object on a touch surface (4) of a light transmissive panel (1). In the apparatus, an illumination arrangement (2, 10) generates a first set of sheets (C1-C3) of light and introduces the first set of sheets (C1-C3) via a first elongate incoupling site on the panel (1) such that the first set of sheets (C1-C3) propagate by internal reflection between the touch surface (4) and an opposite surface. At least two sheets in the first set of sheets (C1-C3) are introduced so as to overlap in a portion of the touch surface (4) such that the object interacts with the at least two sheets. Typically, each sheet (C1-C3) in the first set is essentially collimated in the plane of the panel (1) along a respective main direction. A detection arrangement (12, 14) couples the first set of sheets (C1-C3) out of the panel (1) at a first elongate outcoupling site on the panel (1) and generates output signals indicative of the energy of each sheet (C1-C3) at a set of spatial points within the first outcoupling site. A data processor is connected to identify, in the output signals, attenuation peaks caused by the touching object(s) and to determine the location of the object(s) based on the identified attenuation peaks. |
