Patent ID: 7358477
Filing Date: 2008-04-15
Classification: G06F

Abstract:
1. A method for operating an optical sensing device having a light source and a photodetector device with at least one photosensitive element, said method comprising the steps of: (f1_i) illuminating a surface portion with radiation by means of said light source; (f1_ii) detecting radiation reflected from the illuminated surface portion with said at least one photosensitive element; (f1_iii) while said surface portion is being illuminated, integrating an output signal of said at least one photosensitive element over time; (f1_iv) comparing the output signal integration level with a first integration reference level during integration; (f1_v) interrupting said integration step (f1_iii) if said output signal integration level has reached said first integration reference level, or getting back to comparison step (f1_iv) until a first integration period has elapsed if said output signal integration level has not reached said first integration reference level, and wherein said method further comprises the steps of: (f1_vi) comparing said output signal integration level with a second integration reference level smaller than said first integration reference level, after said first integration period has elapsed; (f1_vii) interrupting said integration step (f1_iii), if said output signal integration level has reached at least said second integration reference level.