The next iPhone could have something other flagship phones already have: a fingerprint sensor buried in the display itself. But if that sounds like Apple is playing catch-up, a newly revealed patent suggests the company will approach this issue in an original and different way that’s not been seen before.
The new patent, spotted by Patently Apple, is the latest from the tech giant in its road to putting Touch ID in the screen, a journey which has seen a number of patents in the past seven years or so.
This latest one is concerned with something called off-axis light. The way a system like this works is that, as the patent explains, “In an under-display fingerprint-sending system, the display consists of active red-green-blue (RGB) pixels that emit light and illuminate the finger placed on top of the display. The light reflected from the finger passes through the openings between the display pixels and is captured by the sensor beneath the display. The contact and noncontact regions between the finger skin and the display’s glass plate generate different light intensity, which thus forms the ridge-valley contrast of the fingerprint.”
I won’t put you through much more patent language, but it goes on to say that problems arise “due to the low-light throughput and diffraction,” so that “the fingerprint image may suffer from low contrast and low signal-to-noise ratio.”
That’s where this new patent comes in, which, “provides a method to capture the off-axis angular light from the finger by insertion of angle-dependent filtering options between the display and the sensor. This method can improve the contrast of fingerprint impressions and maintain the compactness of the entire sensing system.”
In other words, Apple may be late to the party with this kind of feature, but it’s aiming to do it better through its particular design which will increase light to improve quality.
What’s interesting here is that Apple is focusing on optical sensors rather than the ultrasonic kind used by Samsung in its flagship S series phones, for instance.
These are expensive and it seems that Apple is investigating whether optical sensors, improved with new approaches like this, will offer the same quality of fingerprint recognition without the high expense of ultrasonic.
There are other new elements, too. Such as the gratings which comprise the optical layer. In the course of the patent, there are several mentions of different kinds, such as blazed gratings or—and how cool does this sound?—holographic gratings.
The different kinds of gratings are aimed at the same result, that is ensuring off-axis angular light can be maximized to improve the result.
One thing that’s especially likely, by the way: Face ID will be on board as well—Apple has repeatedly said Face ID is more secure than Touch ID, so you can be sure it’s not going to reduce the level of security on a future iPhone.
So, when should we expect this new feature? Well, with a patent, you never know. The patent was filed last August and made public a few days ago. Which means it’s possible that it could be built into the next iPhone when it arrives this Fall.
My guess is that Fall 2022 is a more likely arrival date: in my experience, if there’s a choice between Apple doing something tomorrow or the next day, it usually goes later. As is often said in the context of Apple’s aspirations, “Don’t do it first, do it right.”
Needless to add, there’s also every chance it won’t appear even as soon as next year, or even ever.
But it sounds pretty cool, so let’s hope it happens sooner rather than later.