The fingerprint sensor to be presented uses the bidirectional functionality of light-emission and –detection to detect and analyse the light reflected by a finger as it is illuminated by the OLED display. The first prototype has a native resolution of 1600 dpi, three times more than typically required by the FBI. This high spatial resolution enables the identification even of smallest sweat pores beside the typical papillary lines, which can be used to increase the security.
“We have used an extra-thin encapsulation for the chip of this fingerprint sensor. Thereby the distance between finger and image sensor has been minimized and the fingerprint can be captured excellently. Thus, an additional imaging optics is not necessary for this application”, explains Bernd Richter, deputy division manager for OLED microdisplays and sensors at Fraunhofer FEP.
One of the most promising applications of this new kind of sensor is the user verification in mobile devices. Because of the particularly high resolution in comparison to the typically used capacitive fingerprint sensors these devices are much less vulnerable to so-called spoofing (the manipulation by “false fingers”). Another nice side effect is the opportunity for using the active area as a normal display e.g. for branding, displaying logos or notifications.
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