Patent ID: 8355012

Claim:
A scanning method for determining a touch position of a pointer on a touch input apparatus, said method comprising: (a) providing a touch input apparatus with at least one light emitting device and at least one light receiving device having a plurality of light sensors; (b) performing a first exposure process on the light receiving device by the light emitting device; (c) scanning the light sensors of the light receiving device; (d) locating a light sensor generating a signal with a maximum value; (e) determining a region of partial scan of the light sensors according to the position of the light sensor generating the signal with the maximum value; (f) performing a second exposure process on the light receiving device by the light emitting device; (g) scanning the light sensors within the region of partial scan; (h) locating a light sensor generating a signal with a maximum value within the region of partial scan and determining a next region of partial scan; (i) calculating the maximum value of the signal; and (j) comparing the maximum value of the signal to a predetermined value to determine whether the maximum value is higher than the predetermined value.