In 1995, we obtained our first fingerprint images with an uncooled infrared camera that was designed and manufactured at Thomson-CSF TCS: it showed the feasibility of the project.
Photo: FingerChip 1, the very first chip that we tested. The wire bonding is protected by these two pieces of epoxy: usually, nobody is touching any piece of silicon!
The chip was 128x128 pixels, 300dpi, so large enough to get a nice fingerprint image, but already too large for a production chip: it was a large piece of silicon, too large to be sold at $10 at this time!
As the packaging made for the infrared camera was not practical for fingerprint acquisition, a new and less expensive ceramic package has been designed.
All further chip are CMOS chips, 500dpi: using a CCD process was far too much expensive compared to a regular CMOS process, and the pixels are so large that an old CMOS process is enough.