Fingerprint sensor based on interior optical characteristics of the finger
Emiko Sano, Takuji Maeda, Masahito Matsushita, Masahiro Shikai, Koichi Sasakawa, Masato Ohmi, Masamitsu Haruna · Electronics and Communications in Japan · 2008
Abstract Fingerprints are widely used as a method of personal authentication because they have the best balance among authentication performance, cost, device size, and ease of use. However, conventional fingerprint sensors have problems: the quality of the fingerprint pattern is sometimes not good due to the condition of the finger surface, such as moisture or wrinkles. These problems are caused by the operating principle of the sensors. Most fingerprint sensors detect a fingerprint pattern from the presence or absence of convexities and concavities of the finger surface. To solve these problems, we have devised a new kind of fingerprint sensor, which detects a fingerprint pattern by the use of optical characteristics inside the finger. This method is based on the new scientific discovery that a layer of skin inside the finger has a transmittance distribution corresponding to the pattern of the concavities and convexities of the finger surface. Therefore, this method can detect stable fingerprint images at all times regardless of the finger surface conditions (moisture, wrinkles). In this paper, we describe the principle of a new type of fingerprint sensor and demonstrate the effectiveness of the proposed sensor by examples. © 2008 Wiley Periodicals, Inc. Electron Comm Jpn, 91(7): 48–56, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/ecj.10127