초록 ▼

An optical digitizer is constructed for determining a position of a pointing object projecting a light and being disposed on a coordinate plane. In the optical digitizer, a detector is disposed on a periphery of the coordinate plane and has a view field covering the coordinate plane for receiving th

An optical digitizer is constructed for determining a position of a pointing object projecting a light and being disposed on a coordinate plane. In the optical digitizer, a detector is disposed on a periphery of the coordinate plane and has a view field covering the coordinate plane for receiving the light projected from the pointing object and for converting the received light into an electric signal. A processor is provided for processing the electric signal fed from the detector to compute coordinates representing the position of the pointing object. A collimator is disposed to limit the view field of the detector below a predetermined height relative to the coordinate plane such that through the limited view field the detector can receive only a parallel component of the light which is projected from the pointing object substantially in parallel to the coordinate plane. A shield is disposed to enclose the periphery of the coordinate plane to block a noise light other than the projected light from entering into the limited view field of the detector.

대표청구항 ▼

[ What is claimed is:] [1.] An optical digitizer for determining a position of a pointing object which projects a light and which is disposed on a coordinate plane, the optical digitizer comprising:detector means disposed on a periphery of the coordinate plane and having a field of view covering the

[ What is claimed is:] [1.] An optical digitizer for determining a position of a pointing object which projects a light and which is disposed on a coordinate plane, the optical digitizer comprising:detector means disposed on a periphery of the coordinate plane and having a field of view covering the coordinate plane for receiving the light projected by the pointing object and for converting the received light into a corresponding electric signal;processor means for processing the electric signal output by the detector means to compute coordinates representing the position of the pointing object on the coordinate plane;collimator means disposed to limit the field of view of the detector means below a predetermined height relative to the coordinate plane such that through the limited field of view the detector means can receive a parallel component of the light which is projected by the pointing object substantially in parallel to the coordinate plane;shield means disposed to enclose the periphery of the coordinate plane to block out noise comprising light other than the projected light from entering into the limited field of view of the detector means; anda light source for producing a varying color illumination light over the coordinate plane so that the detector means receives the light which is passively projected by the pointing object by reflection of the illumination light;wherein the detector means receives the light reflected by the pointing object, which has a particular surface color, so that the electrical signal varies in accordance with the particular surface color of the pointing object, and the processor means processes the electric signal so as to discriminate the particular surface color of the pointing object as well as to compute the position of the pointing object.