Fujitsu SweepSensor Secures Wireless Systems

San Jose, Ca. --- Joining Atmel Corp. in a move to provide additional security features for a wide range of net-centric wireless and mobile iAppliances, Fujitsu Microelectronics America Inc. has developed a tiny fingerprint sensor that is about one-tenth the size and less than half the cost of conventional fingerprint sensors.

In devices equipped with the MBF300 SweepSensor, users slide the tip of a finger across a narrow sensor region rather than press down on a finger sensor pad. Software then reconstructs an image of the fingerprint, identifies its unique markers and decides whether it matches the fingerprint templates stored in a system's memory.

The SweepSensor is intended for use in portable gear such as personal digital assistants and cellular phones. To make it small enough for portable applications, the sensor area was cut down to 4.3 x 14 mm, or about one-tenth the size of the company's current fingerprint sensors. The entire SweepSensor is 1.2 mm high.

Advanced packaging and a flexible connector allow the sensor to be embedded onto the side of a personal digital assistant (PDA) or into the base of a cellular phone.

Fujitsu also aims to slash the cost of fingerprint sensors by offering samples for $13.50 and $10.50 apiece in quantities of 1,000. Its larger fingerprint sensors, which capture the image of a fingerprint using a pressing rather than sweeping motion, are priced between $25 and $30.

To generate interest in fingerprint biometric sensors, Fujitsu is working with software vendors to make the technology compatible with various CPUs and operating systems. The company also hopes to create partnerships with some chip and software vendors that are defining PDA and cellular phone platforms, such as Intel, Microsoft, Motorola, Palm and Symbian.

Like its current line of fingerprint sensors, the MBF300 is based on sensor and software technology Fujitsu licensed from Bell Labs spin-off Veridicom Inc. (Sunnyvale, Calif.). The CMOS-based sensor is made up of an array of capacitor cells that creates an image of a fingerprint by detecting differences in discharge rates as they encounter ridges and valleys on the skin. Software captures the fingerprint image at several intervals and then reconstructs the image. The MBF300 consumes 100 milliwatts of operating current and 50 microwatts during standby.

The sensor's typical false accept rate is once every 1,000 sweeps, which is considered medium-grade when compared with other competing biometric sensors being considered as ways to increase the security of small footprint iAppliances. Iris scanners have lower false accept rates, but integrating them into portable applications is considered impractical. Voice recognition has started to appear as a way to identify users, but it is sensitive to ambient noise and changes in a person's voice.

Atmel Corp. has a CMOS-based device, the FingerChip, with a sensing area of 0.4 x 14 mm that is based on a thermal sensing technique that works well with poor-quality fingerprints that are dry and have shallow valley depths and are resistant to electrostatic discharge.