Apple killed off 3D Touch with their iPhone 11 line-up in 2019 replace by Haptic Touch. Then in June 2022 Digital Trends posted a report titled "iOS 16 is a perfect excuse to bring 3D Touch back to iPhones." The report recounted Craig Federighi, senior vice president of Software Engineering stating back in 2015 that “With 3D Touch, it was only at the moment where we finally got a design experience that’s like, ‘Yes! This is what we want." Digital Trend's reporter Prakhar Khanna made his case for the possible return of 3D Touch, a feature many Apple fans really enjoyed using.  

This week the US Patent & Trademark Office published a patent application from Apple that seemingly relates to 3D Touch. Of course Apple patents never identify a patented invention using marketing terms like "3D Touch even though the terminologies and methods blend together in this patent.

Apple's latest patent claims for this invention clearly states that "a first beam of coherent light emitted by a first VCSEL intersects the user input surface at a right angle; a second beam of coherent light emitted by a second VCSEL intersects the user input surface at a first acute angle in a first plane; a third beam of coherent light emitted by a third VCSEL intersects the user input surface at a second acute angle in a second plane that differs from the first plane; and the set of sensors is configured to measure interferometric parameters associated with the first, second, and third beams of coherent light, and use the measured interferometric parameters to characterize a movement of a user input on the user input surface." This is referenced several times about 3 distinct levels of touch.

Self-Mixing Interference Based Sensors For Characterizing Touch Input

Apple's patent describes an electronic device having a touch input surface; first, second, and third lasers within the electronic device, which lasers are configured to emit respective coherent light toward the touch input surface; and a set of sensors configured to detect a respective property of each of the first, second, and third emitted coherent light. 

The second and third lasers may be configured non-collinearly with respect to the first laser. The first detected property of the first coherent light may be used to detect a user-caused deflection of the touch input surface, the deflection being perpendicular to the touch input surface. The second detected property of the second coherent light may be used at least in part to detect a lateral movement or motion of the user-caused deflection of the touch input surface, in a first direction, and a third detected property of the third coherent light emitted may be used at least in part to detect a lateral movement of the user-caused deflection of the touch input surface in a second direction, with the second direction being different from the first direction.

Apple further describes a method of detecting a user input on a touch input surface of an electronic device. The method includes emitting first, second, and third coherent light beams from respective first, second, and third VCSELs that are internal to the electronic device. The method includes applying a sinusoidal modulation to a bias current of at least one of the first, second, and third VCSELs, at a modulation frequency, and measuring a signal of an interferometric parameter associated with the at least one of the first, second, or third VCSELs.

The method may also include: determining a first value by demodulating the signal of the interferometric parameter at the modulation frequency; determining a second value by demodulating the signal of the interferometric parameter at twice the modulation frequency; and determining a displacement of the touch input surface using the first value and the second value.

Apple's patent FIGS. 1A and 1B illustrate the two devices that are the focus of this invention; FIG. 2A illustrates a cross section of a transmissive touch input surface of an electronic device: FIG. 2B illustrates a cross section of an electronic device with a reflective touch input surface capable of deflection; and FIG. 2C illustrates a cross section of a mixed mode touch input surface capable of deflection.

Apple's patent FIG. 3A illustrates part of a laser system that may use a VCSEL for detecting user input on a touch input surface; FIG. 6B shows a perspective view of lasers in a laser system for detecting user input.

Review Apple's patent application 20230288186 for its original details and its 20 new patent claims in this continuation or "updated" patent application that seemingly supports a 3-laser system for various levels of touch input. If Apple is updating its 3D Touch patent, does it mean that it could return to Apple products? That's the million dollar question.

If you're confused about the differences between 3D Touch and Haptic Touch, MacRumors has a nice report on this titled "Haptic Touch vs 3D Touch: What's the Difference?" that's worth checking out.