The US Patent and Trademark Office published a patent application from Apple that reveals that the company has been working on developing under-display Touch ID for future iPhones, Macs, TV Screen, and more.
The patent file bears the number 20200387684 and was filed back in May 2020.
The apparatus consists of a light-emitting layer, an optical layer, a filter layer, and a pixilated image sensor. The light-emitting layer is covered by a transparent layer. It can emit light to illuminate a surface touching the transparent layer, and allows transmission of reflected light from the surface to the optical layer.
The optical layer includes a plurality of optical elements. The filter layer includes a number of apertures and spatially processes the reflected light. The pixelated image sensor can sense the spatially processed light. Either one of the optical layers or the filter layer is responsible for an angle-focused FOV filtering of the reflected light.
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Whereas in some implementations, the optical layer includes a microlens layer, in one or more implementations, the optical layer is used to enable the angle-focused FOV filtering of the reflected light. Additionally, some implementations also show that the filter layer is a fibre optics plate including a collection of optical fibre films bundled with an opaque separator material.
However, Apple has to overcome a series of challenges before actually go into production for the under-display Touch ID. Some of the major challenges include consistency in performance over time especially since the glass-air interfaces are not stable enough for small area matching. On the other hand, the large-area sensors are not cost-effective. Also, the separation of different reflection rays at various angles also poses a problem.
Most Chinese OEMs are likely to adopt the new under-display fingerprint by 2021 and Samsung will probably come out with the Galaxy S21 that will come with a new version of the fingerprint recognition sensor at the bottom of the screen.
Keeping all of this aside, we have to keep in mind that the nature of the use of this patent from Apple remains a mystery as of now.