A patent application for an under-display optical fingerprint biometric sensor based on a narrow field-of-view collimator filed 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, numerous intellectual property filings and other indications have suggested it is at least under consideration.
The filing for an under-display optical fingerprint sensor with an NFV collimator and TFT/organic imager depicts a biometric sensor implemented in a touch-display layer covered by a transparent layer. The invention includes a collimator layer and a pixelated image sensor. A collimator is a device that narrows or focuses a beam of particles or light. The collimator enables a one-to-one imaging ratio between the sensor area and the corresponding fingerprint image.
The under-display optical fingerprint sensor imaging system comprises a thin-film transistor (TFT)-based organic sensor, which captures reflected light emitted by an OLED display.
The collimator layer comprises 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.
Glass-air interfaces present a problem for the consistent performance over time of optical fingerprint sensors, as the interface tends to need to be more stable for small-area matching. Large-area CMOS sensors could solve the problem, but they could be more cost-effective, according to the patent application.
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