Apple is working on a new fingerprint sensing technology that can work through an iPhone display by taking advantage of off-axis square lighting.
In a new patent application, Apple introduces an optical fingerprint sensor that uses light – rather than ultrasonic vibrations – to read and analyze fingerprints. The new patent application outlines a new approach using re-exposed light in particular.
As the patent points out, the technology addresses some of the issues with light-based fingerprint sensors. In fact, it reduces problems with light reaching enough of the fingerprints for clear reading, as well as problems with light contrast.
Apple explains that by capturing off-axis square light, the method could “improve fingerprint differentiation of ideas and maintain the consistency of the entire sensing system.”
Credit: Apple
“For some objects, oblique light creates stronger image signals than light normal for the image plane. For example, a fingerprint sensing system / device with multi-directional illumination, such as a sub-fingerprint sensing device, can use an oblique square sieve display to capture the stronger signals to enhance image differentiation, ”the patent reads.
In one implementation of the patent, Apple could incorporate a light-emitting coating covered with a transparent coating to illuminate a surface. The basic layers in this configuration could include a grating cover, a collimator cover, and a pixelated image sensor.
The grating phase would bend the reverberated light to create oblique light. From there, several openings and the collimator cover could spatially process the received light. An image sensor could then further analyze that processed light. Another method involves Fresnel prisms or warm grafting to reconnect the oblique rays of light to direct rays of light.
All of these methods created a fingerprint reading system that could work reliably through a display, but without taking up too much space inside an iPhone or other device.
The patent names Ting Sun, Mohammad Yeke Yazdandoost, Bosheng Zhang, Marduke Yousefpor, and Kathrin Berkner Cieslicki as the entrepreneurs.
Apple files several patent applications each week, so patents are a bad indicator of when or whether a particular feature or technology will bring it to market.