Optical touch device and touch sensing method

摘要

An optical touch device includes an indication plane, two image sensing units and a processing unit. The two image sensing units are disposed at two corners of the indication plane diagonal to each other, respectively, and the two corners define a diagonal line connected therebetween. The processing unit is electrically connected to the two image sensing units. When two touch points are performed on the indication plane, the processing unit determines whether the two touch points are located at opposite sides of the diagonal line, respectively, according to images sensed by the two image sensing units. Once the two touch points are located at opposite sides of the diagonal line, respectively, the processing unit calculates and outputs coordinates of the two touch points immediately according to the images sensed by the two image sensing units.

主权项

1. An optical touch device comprising:
an indication plane having four corners; only two image sensing units disposed at two of the four corners of the indication plane diagonal to each other, respectively, the two of the four corners defining a diagonal line connected therebetween; and a processing unit electrically connected to the two image sensing units; wherein when two touch points are performed on the indication plane, the processing unit determines whether the two touch points are located at opposite sides of the diagonal line, respectively, according to images sensed by the two image sensing units; once the two touch points are located at opposite sides of the diagonal line, respectively, the processing unit determines that there is no ghost point immediately without performing any additional processes of identifying ghost point and then calculates and outputs coordinates of the two touch points immediately after determining that the two touch points are located at opposite sides of the diagonal line; once the two touch points both are located at one side of the diagonal line and are performed on the indication plane simultaneously, the processing unit identifies the two touch points as real touch points and then calculates and outputs coordinates of the two touch points according to brightness of the two touch points sensed by the two image sensing units; once the two touch points both located at one side of the diagonal line and are not performed on the indication plane simultaneously, the processing unit identifies the two touch points as real touch points and then calculates and outputs coordinates of the two touch points according to appearance sequence of the two touch points sensed by the two image sensing units; once the two touch points both are located at one side of the diagonal line and are both moving on the indication plane, the processing unit identifies the two touch points as real touch points and then calculates and outputs coordinates of the two touch points according to the moving trajectories of the two touch points.