US Patent 7292321 Contact detection sensor and contact detection method

A low-cost contact detection sensor and contact detection method for easily detecting a contact by a third party is provided. A contact detection sensor comprises an antireflection structure including structure elements having a predetermined shape which are put in an array periodically at a pitch smaller than a wavelength of visible spectrum; and a substrate including the antireflection structure in at least a part of a surface portion thereof. The antireflection structure distinguishes whether the detection target is contacted by a human body or not based on a change in reflectance which occurs to an area of the detection target contacted by the human body when the detection target is contacted by the human body.