Patent ID: 7715601

Claim:
A fingerprint acquisition apparatus used for sensing a pattern of a fingerprint, the fingerprint acquisition apparatus comprising: a plurality of sensing units, each of the sensing units comprising: a first metal plate; a second metal plate; a third metal plate; and a built-in capacitor; wherein for each sensing unit, an inducing capacitor is formed between the first metal plate and the fingerprint when the sensing unit is touched by the fingerprint; the built-in capacitor is connected between the second metal plate and the third metal plate; and the built-in capacitor and the inducing capacitor together form a first potential when the sensing unit is touched by a ridge portion of the fingerprint, the built-in capacitor of the sensing unit and the inducing capacitor together form a second potential when the sensing unit is touched by a valley portion of the fingerprint, and the first potential is different from the second potential.