In October 2022 Ming-Chi Kuo predicted that Apple would introduce solid-state buttons. Then in April 2023, Kuo wrote: … "due to unresolved technical issues before mass production, both high-end iPhone 15 Pro models (Pro & Pro Max) will abandon the closely-watched solid-state button design and revert to the traditional physical button design."

While it's unknown if this feature has been official killed or simply delayed is unknown at present, though today the U.S. Patent and Trademark Office officially published a patent application from Apple that updates their invention relating to solid state buttons and providing a much simpler way of shutting down your iPhone without the need to ever touch a physical side button again.   

Many electronic devices with displays include mechanical buttons, such as mechanical home buttons, volume buttons, and power buttons. But mechanical buttons provide little, if any, feedback to a user beyond a fixed down click and a fixed up click.

Apple notes in their patent that there's a need for electronic devices with improved methods and interfaces for interacting with a control (e.g., controls for device functions, such as volume, ringer, and power, etc.), and providing visual, haptic, and/or audio feedback during interaction with the control.

In some embodiments, an intensity-sensitive side button or surface (e.g., a mechanical button, solid state button, or a touch-sensitive surface) is provided separately from the display (e.g., on a side edge of the display) on the device. User inputs detected on the intensity-sensitive side button or surface are used in conjunction with user inputs detected on touch-screen to cause display, adjustment/activation, expansion, and dismissal of the control. The device provides visual feedback on the display in conjunction with haptic feedback on the intensity-sensitive side button or surface to help the user interact with the control more easily and more efficiently.

There is also a need for electronic devices to have fewer buttons on the surface of the device, to reduce device manufacturing and maintenance complexity and cost.

Ah, finally a simple way to shut off your iPhone. Apple notes that an on-display power button (see Patent figures below) is provided in a control user interface that includes multiple other controls to allow the user to turn off the device without using a solid state or mechanical power button on the front, back, or sides of the display. This frees up the limited number of physical and/or solid state buttons available on the device for other more frequently accessed functionalities (e.g., volume control, ringer control, camera control, etc.).

(Click on image to Greatly Enlarge)

If an on-screen icon turns off your iPhone, how do you turn your iPhone back on when the screen is black? Well, Apple answers that this way:

One or more of the limited number of physical and/or solid state buttons provided on the device is used to turn on the device, when other functionalities of the device are not yet needed or available. In other words, the functionalities of the limited number of physical and/or solid state buttons can be automatically differentiated when the device is off versus when the device is on, reducing the device complexity without reducing the device's functionality.

In some embodiments, the device is portable (e.g., a notebook computer, tablet computer, or handheld device).

Apple's patent FIG. 2D below is an intensity-sensitive pivoting device in the form of a button. The Input surface #712 of the button/input structure #710 may be touched, pressed, swiped in one or more directions, or otherwise interacted with by a user.

In some embodiments, input surface 710 may translate, deflect, bend, or otherwise move a relatively small distance in response to user input and/or in response to a movement of permanent magnet 726. In other embodiments, input surface 712 does not translate, deflect, bend, or otherwise move in response to a user input. Input may be detected through various intensity sensors (e.g., force sensors, touch sensors, or combination of the two). Such sensors are not shown for simplicity's sake.

Apple's patent FIGS. 5A1-5A3 and FIG. 5A9 above illustrate exemplary user interfaces for interacting with a new volume control system. The exemplary user interfaces provide tactile outputs and visual feedback in response to multiple types of inputs on intensity-sensitive input regions.

The touch-sensitive input regions provides different haptic feedback in response press inputs that have different characteristic intensities. In some embodiments, one or more of the touch-sensitive input regions are mechanical buttons or switches that are actuated in response to press inputs detected on the mechanical buttons or switches.

In some embodiments, the one or more of the touch-sensitive input regions are solid-state buttons and switches that do not actuate in response to press inputs but provides haptic feedback (e.g., via tactile and/or audio outputs) that mimic button presses and actuations on the solid-state buttons. 

Apple's patent FIG. 5A14 above illustrates an alternative control design that is narrower and not interfering with the user interface icons.

While most of Apple's patent figures present the option of physical buttons, albeit solid-state buttons, Apple's patent FIG. 4A below illustrates an iPhone design where the solid-state buttons are flush with the sides of the iPhone to provide a much cleaner appearance.

Technically, Apple notes: "As shown in FIG. 4A, in some embodiments, the portable multifunction device 100 does not include a home button on the display-side of the device, and the touch-screen 112 occupies substantially all of available areas on the display-side of the device. The device 100 as shown in FIG. 4A includes a number of discrete intensity-sensitive input regions 455, 456, and 457. The input regions 456 and 457 are optionally implemented on two sub-portions of a contiguous touch-sensitive surface. Each of the input regions are coupled with a respective set of one or more localized tactile output generators for generating localized tactile outputs that have greater amplitudes at the input region (or a respective sub-portion thereof), and smaller amplitudes or negligible amplitudes at locations outside of the input region (or the respective sub-portion thereof)."

For more on this, review Apple's patent application 20240053847. Apple began work on this going back to 2019. In Apple's patent update they've added 12 new patent claims relating to "the method" of the invention.

Previous Patent Reports on this subject matter:

January 2023: Apple Patent reveals Intensity-Sensitive Off-Display Input Regions that are superior to a "Solid State" button system now being rumored

June 2023: Apple's work on Possible Future iPhone Solid-State Sidewall Buttons using Force Touch Sensors revealed in new Patent Filing