Patent ID: 7864992
Filing Date: 2011-01-04
Classification: G06K

Abstract:
1. A fingerprint sensor element, comprising: a fingerprint sensor electrode formed in an upper conducting layer, a lower electrode formed in a lower conducting layer, at least one insulating layer between the upper conducting layer and the lower conducting layer, a charge amplifier having a negative input terminal and a positive input terminal and an output terminal, wherein an upper side of the fingerprint sensor electrode is arranged for facing a finger, wherein a lower side of the fingerprint sensor electrode is arranged for facing the lower electrode, where the fingerprint sensor electrode and the lower electrode are arranged in such a way that a capacitance is formed between them, where the positive input terminal of the charge amplifier is connected to an essentially fixed potential, wherein the fingerprint sensor electrode is arranged for being connected to the negative input terminal of the charge amplifier, such that the fingerprint sensor electrode is maintained at an essentially fixed voltage potential, wherein the lower electrode is arranged for being connected to the output terminal of the charge amplifier.