Today the US Patent & Trademark Office published a patent application from Apple that relates to devices that include one or more photodetectors, such as biometric sensors, cameras, depth sensors, and so on. More particularly, the described embodiments relate to the positioning of such sensors behind a display. The invention could apply to future devices like the iPhone, iPad, Apple Watch and many new applications such as vehicle navigation systems, health monitoring devices. Apple envisions that their invention could also apply to the Internet of Things like a thermostat, refrigerator and other appliances.

Although the "possible" applications are many, Apple's patent figures have a deadly focus on Touch ID under the display of an iDevice.

Apple notes that an array of photodetectors may be used, for example, for security, health monitoring, or entertainment purposes. For example, when used for security purposes, an array of photodetectors may be used to obtain biometric information, such as fingerprints, palm-prints, 3D face scans, or retina scans. The biometric information may then be used to identify or authenticate a user.

When used for health monitoring purposes, an array of photodetectors may be used, for example, to acquire an electrocardiogram (ECG), pulse, or ophthalmic scan from a user.

When used for entertainment purposes, an array of photodetectors may be used, for example, for palm reading, social networking, or social matching.

Apple presents a series of four patent (6A-6D not shown) that detail various example configurations of the display stack.  Each of the configurations shows a sensor module that may be attached to the backside of a display.

In some cases, the sensor module may be attached to the display using an adhesive, such as an optically clear adhesive (OCA) 604.

In some cases, the sensor module may be attached to the display via one or more optical elements or arrays of optical elements such as one or more lenses (e.g., micro-lenses), collimators, optical waveguides, optical polarizers, or optical films.

Apple's patent FIGS. 4A-4C below show a first example configuration of the stack 400 (a device stack, or display stack. The stack (#400) may include a display (#402), an optional array of optical elements (#404 - or optical element, such as one or more lenses (e.g., micro-lenses), collimators, optical waveguides, optical polarizers, or optical films) positioned behind the display, an array of photodetectors #406 positioned behind the display or optional array of optical elements and a processor #408 (e.g., a silicon-based integrated circuit (IC), such as a System-on-Chip (SOC)) positioned behind the array of photodetectors.

More specifically, In Apple's patent FIG. 4A the display may emit electromagnetic radiation #410 (e.g., electromagnetic radiation, such as visible light, that defines an image; electromagnetic radiation having one or more predetermined wavelengths and emitted primarily or solely for sensing purposes.

Apple notes that when an object #412 (e.g., a finger, face, or stylus) is placed within the emission field of the emitted electromagnetic radiation, some of the electromagnetic radiation may reflect or backscatter off the object #412 (a finger) and impinge on the display. Some of the reflected or backscattered electromagnetic radiation #414 may pass through the display, as shown in FIG. 4B above.

In Apple's patent FIG. 4C above the signals #416 of different photodetectors may be received by the processor #408 individually, or may be combined in various ways and provided to the processor. In some cases, the processor may generate an image (2D image) of the finger object 412 or a depth map (3D image. The processor may also or alternatively use one or more signals #416 received from the array of photodetectors to extract biometric information for the finger object.

Apple's patent FIG. 3 above shows an example plan view of arrays of light-emitting elements and photodetectors that may be included in a stack positioned under the cover display of the device

Although the invention could be used for Face ID and future Iris Scanning, Apple's patent figures clearly support Touch ID on or under the display. Apple's patent claims stay clear of applications and focuses on a device's display make up supporting attached photodetectors.

Apple's iPhones today have Face ID cameras under the display and so what's new is it applying to Touch ID. There's no mention of eliminating the iPhone notch at any point as those who have tried to use cameras under the display without a notch basically failed. So that's a story for another day. While the potential for advanced photodetectors will eventually extend to other devices and applications, the closest to becoming a reality in the short run is for Touch ID.

Apple's patent FIG. 12B below shows one configuration of a sensor module.

For finer details, review Apple's patent application number 20210050385.

Considering that this is a patent application, the timing of such a product to market is unknown at this time.