Patent application shows how Apple could opt to preserve Touch ID via pinhole-sized sensors in next-gen iPhone displays

The next-gen iPhone could retain Touch ID, albeit through a series of pinholes that would allow a fingerprint to be captured through the screen.

Where the introduction of the iPhone X in 2017 eliminated the famous Home button in favor of an edge-to-edge display, Apple had to reconsider where to place its Touch ID feature, which had been house in the Home button.

Apple’s ultimate answer was to replace it with Face ID, using the TrueDepth camera array to authenticate the user instead of their fingerprint. While other device producers simply shifted the fingerprint reader to elsewhere on the device, typically on the rear, Apple opted to fundamentally change its security processes instead. 

Still, a patent application published by the U.S. Patent and Trademark Office on Thursday revealed that Apple seems to be considering how to retain Touch ID while using a larger display that seemingly offers no space for a reader. The filing “Electronic device including pin hole array mask above optical image sensor and laterally adjacent light source and related methods” was filed on May 23, 2016, over a year before the iPhone X’s launch, suggesting it was still a consideration at that point. 

The patent filing suggests using many small holes in the display panel to allow light to pass through to an optical image sensor below. By shining light onto the user’s finger, reflected light could pass through the holes to the optical sensor, and could be used to produce a fingerprint. 

A cross-section of the display, showing pinholes allowing light to pass through the display for fingerprint reading

The holes would be equally spaced between pixels on the display panel, so as not to be easily visible to the user.

A light source laterally adjacent to the imaging sensor is also used to shine light though the holes onto the user’s finger, as while the light from the display panel could do a similar job, doing so with a separate light source leaves the display available to be used for other tasks, as well as enabling the use of infrared or ultraviolet light for fingerprint reading. 

A transparent layer may also be used between the display panel and the pin hole array mask layer, which can give space for light to reflect against the user’s finger and bounce back to the holes, passing through to the sensor. 

Despite using pinholes, using a plurality of them will give enough data to the sensor to be able to make an image of the user’s finger. Prototype test images show the concept working with text and lines down to a micron level, making it more than sufficient enough for fingerprints. 

Apple suggests the use of the system would also potentially save users time, as it could eliminate the authentication step in a process by simply reading the finger when it touches the display when required. 

If adopted, this technique would effectively turn the entire display into a fingerprint reader, allowing the biometric data to be captured where any finger touches the display, and at any angle.

Granted, this is just a patent application and in no way a definitive road map as to what lies ahead, but it’s still interesting.

Stay tuned for additional details as they become available.

Via AppleInsider and the United States Patent and Trademark Office