Image Number 12 for United States Patent #7746326.
A coordinate input apparatus is provided. A photo transmission/reception unit includes a phototransmitter which projects light along a plane of an input region, and a photoreceptor which detects incoming light. A reflector is arranged on a rim portion of the input region, and reflects incident light from the phototransmitter toward the photoreceptor. A detection unit detects a shade formed by the pointing operation of a pointing device using the photo transmission/reception unit. And an output unit calculates a coordinate value of the position based on a state of the detected shade, and outputs information of the coordinate value. The pointing device includes a transmission unit configured to transmit a control signal including information of a unique identifier based on the pointing operation, and the output unit extracts the information of the identifier from the control signal transmitted based on the pointing operation associated with the shade, and appends the information of the coordinate value when that information is output.