New optical in-display sensor for fingerprint biometrics described in Apple patent filing
A patent application for an under-display optical fingerprint biometric sensor based on a narrow field-of-view collimator filed by Apple has been published by the U.S. Patent and Trademark Office (USPTO).
While an in-display version of Touch ID biometrics has not been announced by Apple, but numerous intellectual property filings and other indications have suggested it is at least under consideration.
The filing for a ‘Under-display optical fingerprint sensor with NFV collimator and TFT/organic imager’ depicts a biometric sensor implemented in a touch-display layer and covered by a transparent layer. The invention includes a collimator layer and a pixelated image sensor. A collimator is a device which narrows or focuses a beam of particles or light. The collimator is configured to enable a one-to-one imaging ratio between the sensor area and the corresponding fingerprint image.
The imaging system is made up of a thin-film transistor (TFT)-based organic sensor, which captures reflected light emitted by an OLED display.
The collimator layer is made up of a fiber-optic or micro-aperture plate configured to achieve a field of view with a range of plus or minus 0.5 to 10 degrees. The transmission range of the collimator layer would be roughly -6 dB to 0 dB.
Apple suggests that glass-air interfaces present a problem for the consistent performance over time of optical fingerprint sensors, as the interface tends not be stable enough for small area matching. Large area CMOS sensors could solve the problem, but not are not cost-effective, according to the patent application.
iPad Mini 6
Another indication that in-display Touch ID biometrics are coming to Apple devices is a leak of Apple iPad Mini 6 details reported by Gizmochina.
The report attributes the leak info to David Kowalski, who Gizmochina says has an established track record for breaking mobile device specs. The Touch ID conclusion appears to be drawn from company illustrations.