Patent ID: 7990464
Filing Date: 2011-08-02
Classification: H04N

Abstract:
1. A focusing device used in an imaging system utilizing a lens, comprising: a vertical-synchronization-signal generator capable of generating a vertical-synchronization-signal sequence, the vertical-synchronization-signal sequence including a plurality of vertical synchronization signals, a plurality of vertical-synchronization-signal times being formed between two adjacent vertical synchronization signals, a first vertical-synchronization-signal time and a last vertical-synchronization-signal time being formed at a beginning and an end of the vertical-synchronization-signal sequence respectively, each of the plurality of vertical-synchronization-signal times including a sub time and an exposure time arranged sequentially; an excitation-sequence generator coupled to the vertical-synchronization-signal generator, and capable of generating an excitation sequence according to the vertical-synchronization-signal sequence and applying excitation according to the excitation sequence, in the excitation sequence, a preceding excitation being only applied in the sub time of the first vertical-synchronization-signal time, a succeeding excitation being only applied in sub time of the last vertical-synchronization-signal time, a phase-fixed excitation being applied in each exposure time of each of the vertical-synchronization-signal times except the exposure time of the last vertical-synchronization-signal time; and a driving module coupled to the excitation-sequence generator capable of driving the lens of the imaging system to different focusing positions according to the excitation sequence.