Apple has been awarded a patent for an optical sensor that could be used for an under-display fingerprint scanner in a future iPhone, and a report from Patently Apple says the same sensor technology is already in use the new 16-inch MacBook Pro.

While previous iPhones with fingerprint scanners used capacitive sensors, this patent calls for an optical sensor, which relies on light from the smartphone’s display to produce a 2D image.

The fingerprint scanners on this year’s 13 and 15-inch MacBook Pro and the MacBook Air are of the capacitive variety, but the 16-inch MacBook Pro is equipped with the kind of optical sensor outlined in the patent, which Apple filed in 2017 and was awarded this week by the US Patent and Trademark Office (USPTO). In the case of the 16-inch MacBook Pro, however, the sensor is embedded beneath the power button — the same location as the capacitive sensors on the other models.

As the patent explains how this sensor could be embedded under a device’s display:

“An optical image sensor is carried by the housing under the display. The optical image sensor senses biometric image data associated with a user, such as, for example, data representative of a biometric image of the fingerprint patterns of the user’s finger. The controller may perform an authentication function by matching the acquired biometric image data to the stored biometric template data stored in the memory, for example. The controller may perform and/or restrict functionality of the electronic device based upon the authentication.”

Apple used Touch ID for biometric authentication starting with 2013’s iPhone 5S up until the debut of Face ID in the iPhone X in 2017. There is speculation, however, as to whether Apple will bring back Touch ID in under-display form for its future iPhones.

The possibility of having a new form of Touch ID that takes advantage of an under-display fingerprint scanner and Face ID working together for a multimodal form of biometric authentication is one way that Apple may choose to go.

Sources: 9to5Mac, SlashGear, Patently Apple