Patent ID: 8593416

Claim:
A touch device, comprising: a touch panel; a sensing unit, coupled to the touch panel, for scanning a scan area of the touch panel to output a touch signal; and an operation unit, coupled to the sensing unit, for determining the scan area according to the touch signal, when the touch signal corresponds to a first closed path, the operation unit defines a closed area formed by the first closed path as a first sub touch area; wherein when the first sub touch area is undefined, the operation unit chooses a whole touch area of the touch panel as the scan area; when the first sub touch area is defined, the operation unit chooses the first sub touch area as the scan area, and a coordinate of the first sub touch area is stored in the operation unit, wherein the operation unit comprises: an interpolation unit, for calculating positions of a plurality of single-touch points according to the touch signal; and a sub touch area detector, coupled to the interpolation unit, wherein when the positions of the single-touch points form the first closed path, the sub touch area detector defines the closed area formed by the first closed path as the first sub touch area, wherein the interpolation unit further calculates positions of multi-touch points according to the touch signal, and when the scan area chosen by the sub touch area detector is the first sub touch area, the scan area is changed to the whole touch area of the touch panel according to the positions of the multi-touch points corresponding to the first sub touch area, or the first sub touch area is moved according to a moving trajectory of the positions of multi-touch points.