Getting To Know You

From car-entry systems to cell phones and PDAs, fingerprint sensors are on the front line of security. Director, Biometric Sensors Product Group Fingerprint sensors are getting smaller and more reliable and provide security for automotive entry, cell phones, and PDAs. Fingerprint sensors from Fujitsu capture a fingerprint image. Software then digitizes the image data, creating a template unique to the fingerprint. The system tests for matches between the sample and a candidate template. False accept and reject rates are small, well under 1%. Capacitive-based sensor ICs require little power and current to deliver a rapid, reliable match. This cross section shows the three layers in the Fujitsu MBF300 sweep sensor and the differing capacitance associated with fingerprint ridges and valleys. More and more products now incorporate fingerprint sensors. They include computer keyboards and mice, along with the keypads of access-control systems. With approximately 1048 possible fingerprint patterns, duplicate patterns are virtually impossible. Fingerprint sensor ICs are showing up in PCs, PDAs, and cell phones. They're replacing identification techniques requiring passwords and personal ID numbers (PINs) that are often lost, forgotten, or stolen. They're also generally more efficient and dependable than older methods used by law-enforcement agencies, such as the basic ink-fingerprinting method, because they store only data about specific points of the fingerprint rather than the full image. Three different types of fingerprint-sensing devices are now in production or planned. These include sweep, single-touch, and in the future, trusted sensors. Sweep sensors are ideal for compact, computer, and communications products that need rapid, easy access by users. Single-touch sensors are finding use in consumer products such as vehicles and home-security systems. Each sensor type uses a four-stage process that begins with the acquisition stage, in which a PC, phone, or other device captures a fingerprint sample. Data points are extracted from