Feb: Atmel announces the AT 77 C 104, the Finger. 2004 Feb: I-Control becomes Atrua and promotes "Atrua Wings" (ATW 100). Nov: Elsafe installs the first safe with a sweep fingerprint reader, the Finger. Oct: YRP shows the Ubiquitous Communicator, a R&D study prototype, containing the Atrua sweep sensor. Jul: Sharp announces the Mebius Muramasa, the first Tablet PC with a build-in sweep fingerprint sensor, the Finger. May: Digital Persona unveils the Firefly, a sweep optical fingerprint sensor using a roller. 2003 Feb: Alps Electrics + Casio unveiled their "rolling-tube head" scanner. PAQ h 5450 is the first PDA with a built-in fingerprint sensor, the Finger. Oct: I-Control promotes the ICS 3000 / PDS 3000 Nov: Authentec introduces the AES 2500. Summer: Tima publishes about a sweep tactile sensor. 2002 Feb: Fujitsu announces the MBF 300, and shows it at the CTST in May. Pad, the first watch with a built-in fingerprint reader, the Finger. Sept: Fingerprint Cards announces the FCP 1030. L l l l l l l l l l 2001 April: Idex & STm announce the development of Smart. INO (Institut National d'Optique / Canada) has used bolometers to make a 160 x 120 pixel fingerprint sensor (US patent 6, 633, 656). Nagoya University has studied a thermal sensor based on MEMS, using a resistor to heat a sensor above a cavity. Chip Hunno Technologies & Hyung-Kew Lee (Korea, KAIST) have studied a thermal fingerprint sensor in 1999, probably using bolometers. Atmel (formerly Thomson-CSF) proposes the Finger. This effect disappears when you sweep your finger over the sensor, because of the touch/no touch of ridge/valley. The finger and the chip have reached thermal equilibrium, and as there is no change in temperature, there is no signal. When you place your finger on the sensor, there is a big change of temperature, and therefore signal, but after a short period (less than a tenth of a second), the image vanishes. A drawback of the technique is that the image disappears quickly. The valleys don't make contact, so the temperature of the pyro-electric material under the valleys remains almost unchanged. In fact, as the finger is directly placed on the material, the ridge's temperature is what's measured, as it's in contact. This type of sensor doesn't measure the difference of temperature between the skin in the ridges and valleys, because the difference is negligible. This effect is quite large, and is used in infrared cameras. Thermal l l Pyro-electric material is able to convert changes in temperature into a specific voltage.
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