Optical authentication systems are frequently used in everyday life, providing swift and uncomplicated access to personalized applications in smartphones and other technical devices without the need to enter a password. Although these are easy to use, the underlying authentication systems have to meet high security requirements: They must be reliable and spoof-proof.
A robust, optical fingerprint sensor for personal authentication in security-critical applications will be developed within the "KomFiDis" project. In comparison with capacitive measuring techniques, the optical sensor offers live and fake finger detection, for example, which makes manipulation using fingerprint imitations more difficult as a means of ensuring a higher level of protection against falsification.
In order to achieve this aim, a bi-directional OLED on a CMOS micro-display will be expanded to include a lens array measuring only a few micrometers in the course of this research project. The display can illuminate and record images at the same time, achieving high, optical finger-imaging quality of the finger on the image-recording photo diode matrix. The integrated OLEDs on the chip ensure suitable lighting for recording an image of the finger.
The principal challenge lies in achieving precise and economical replication of these particularly small structures and in incorporating them into the bi-directional display. It is anticipated that the outcome will be a demonstration optical sensor system boasting both reduced dimensions and lower manufacturing cost than conventional products. The demonstration of a continuous production chain culminating in assembly at chip and wafer level and of their underlying principles will open up a large number of new target markets for a range of additional potential applications. The Fraunhofer IPT is responsible for the development and manufacture of a micro-lens array and for ensuring high-precision assembly of the optics on the bi-directional micro-display.