Patent ID: 6980008

Claim:
An uneven pattern detector for detecting an uneven pattern on a detection object placed on a detecting surface, comprising: a drive circuit; a detecting circuit; a plurality of drive signal lines connected to the drive circuit; a plurality of detecting signal lines connected to the detecting circuit, arranged so as to cross the plurality of drive signal lines respectively; and a plurality of detecting elements respectively corresponding to intersections of the plurality of drive signal lines and the plurality of detecting signal lines, wherein each of the respective detecting elements includes: a switching element switched ON and OFF respectively in response to an active signal and a non-active signal applied to a corresponding drive signal line which is a drive signal line passing through a corresponding intersection, a detecting electrode connected via the switching element to a corresponding detecting signal line which is a detecting signal line passing through a corresponding intersection, and an auxiliary capacitor electrode provided so as to form a predetermined capacitance with the detecting electrode; wherein the drive circuit applies the active signal and the non-active signal to the corresponding drive signal line so as to switch the switching element ON and OFF; and the detecting circuit supplies a predetermined potential to the corresponding detecting signal line, and detects a resulting capacitance formed between the detection object and each of the detecting electrodes according to the uneven pattern, based on electric charges transferred between the detecting circuit and each of the detecting electrodes via the corresponding detecting signal line and the switching element.