Today the US Patent & Trademark Office published a patent application from Apple that relates to the field of wearable electronic devices including a wrist biometric sensor. While options for a biometric authentication system for Apple Watch could include Face ID or Touch ID in the future, Apple's latest patent application on this subject matter actually points to an all new form of biometric authentication using a wrist biometric sensor located on the inside portion of a watch band that reads skin texture patterns.

According to Apple, the wrist biometric sensor may include a plurality of biometric sensing pixels. The wearable electronic device may also include a processor coupled to the wrist biometric sensor and configured to cooperate with the plurality of biometric sensing pixels to acquire skin texture pattern images from adjacent portions of the user's wrist, and perform at least one authentication function based upon the skin texture pattern images.

The wrist biometric sensor may include an infrared (IR) thermal image sensor, for example. Skin texture may have a first thermal pattern associated therewith and hair may have a second thermal pattern associated therewith. The processor may be configured to perform the authentication function by thermally distinguishing the first and second thermal patterns, for example. The IR thermal image sensor may include a microbolometer, for example.

The wrist biometric sensor may include an electric field sensor. The wrist biometric sensor may include an optical image sensor, for example.

The wrist biometric sensor may be carried by the device body. The wrist biometric sensor may be carried by the device band.

Apple's patent FIG. 6 below we're able to see the wrist biometric sensor #30 highlighted in yellow which may be carried by the watch band 28 adjacent the palmer side of the user's wrist. It may be desirable to use either an electric field wrist biometric sensor or an optical wrist biometric sensor having electric field sensing pixels or optical sensing pixels, respectively.

Apple's patent FIG. 8 above is a skin texture pattern image of a user's wrist using an optical based wrist biometric sensor.

Further to FIG. 6, Apple adds that the wrist biometric sensor has an IR thermal image sensor that will provide improved accuracy skin texture pattern acquisition through hair. This is because skin texture has a first thermal pattern associated therewith, and hair has a second thermal pattern associated therewith. More particularly, skin texture cracks are generally warmer than the surrounding skin, and hair is cooler than the surrounding skin.

By using an IR thermal image sensor as the wrist biometric sensor, hair can be distinguished, thermally, from skin texture cracks by temperature. Additionally, by using an IR thermal image of the wrist the biometric sensor requires no illumination which is desirable.

Skin textures generally do not have fiducials that are clearly visible to humans for matching as compared to fingerprints, for example. However, the processor and wrist biometric sensor may not rely on humanly discernible fiducials for matching. Accordingly, similar to electric field sensing techniques, the processor may extract textural elements and represent them in an abstract orientation vector field for use in matching, for example, using ridge-flow mappings, vectors, etc.

Apple's patent application was originally filed back in Q2 2018. Considering that this is a patent application, the timing of such a product to market is unknown at this time. Both inventors were associated with AuthenTec, a company Apple acquired to work on Touch ID.

Today, USPTO also published one of Apple's continuation patents regarding Apple Watch. Patently Apple originally covered this invention in a report in March 2018 titled "Apple Patent Points to Face ID coming to Apple Watch along with Band Sensors to Analyze Sports Performance and more." In any continuation patent, the changes and/or additions are always found in Apple's patent claims.

Apple has added, "a method" of determining a performance of a wrist of a user. determining a tension of the wrist of the user using one or more sensors included in a device; determining a motion of the wrist using one or more of an accelerometer, gyroscopic sensors, and barometric sensors included in the device; simulating the performance of the wrist using the determined tension and the determined motion; analyzing the performance by comparing the simulated performance to one or more stored ideal performances; and providing the simulation and the analysis to the user. "

Apple has also added weight training that wasn't in their patent claims in March. For more on this, review Apple's claims in patent application 20180078183.