On Sunday, Bloomberg's Mark Gurman noted in his Power On newsletter that a key focus for Apple's second generation Vision Pro is making it more comfortable to wear — with a smaller and lighter design. The company’s first headset, the Vision Pro, has caused neck Fatigue in testing due to its size and weight. In a new granted patent today, Apple is shown to be working on a new technique of head support that includes a balancing mass

Today, the U.S. Patent and Trademark Office officially granted Apple a patent that relates to A head-mounted display (HMD/Apple Vision) that includes a display unit, a head support, and a balancing mass. The display unit displays graphical content to a user. The head support is coupled to the display to support the display unit on a head of the user for displaying the graphical content thereto. The balancing mass is movable relative to the display unit to offset changes in torque induced by the display unit when tilting the head-mounted display. 

In Apple's patent background they note that a head-mounted display is a device that is worn on a head of a user for displaying graphical content thereto. When worn on the head of the user and in an upright position, a center of gravity of the head-mounted display is typically arranged forward of and above a head-neck pivot joint about which a head pivots relative to a neck of the user. As a result of the center of mass being arranged forward of the head-neck pivot joint, the head-mounted display induces a forward torque thereabout. Furthermore, when the user tilts their head forward, as a result of the center of mass of the head-mounted display being arranged above the head-neck pivot joint, a moment arm of the center of mass moves further away from the head-neck pivot joint. In this way, forward tilting of the head may increase the forward torque induced by the head-mounted display. In order to stabilize the head, the user must exercise neck muscles, which may be uncomfortable and/or induce fatigue, especially when the head-mounted display is worn for long periods of time. Apple's granted patent relates to a remedy for this.

Vision Pro With Changeable Center Of Gravity

Apple's granted patent relates to a head support that is coupled to the display to support the display unit on a head of the user for displaying the graphical content thereto. The balancing mass is movable relative to the display unit to offset changes in torque induced by the display unit when tilting the head-mounted display.

The balancing mass may be moved in response to tilting about a pitch axis formed by a head-neck pivot joint of the user. In an upright position, the balancing mass may be positioned rearward of the head-neck pivot joint and the display unit forward of the head-neck pivot joint. In a forward tilted position that is tilted forward from the upright position about the head-neck pivot joint, the balancing mass may be positioned rearward of the head-neck pivot joint and the display unit forward of the head-neck pivot joint. As the head-mounted display is tilted forward, the balancing mass may be moved away from the display unit to remain positioned rearward of the head-neck pivot joint.

In an implementation, a head-mounted display includes a static mass and a moving mass.

The static mass includes a display unit for displaying graphical content to a user and a head support coupled to the display unit for supporting the display unit on a head of the user. The static mass has a static mass center of gravity that remains generally fixed relative to the head of the user when worn thereon.

The moving mass is movable relative to the static mass. The moving mass has a moving mass center of gravity that is movable relative to the head of the user. The moving mass is movable in response to movement of the head-mounted display about a pivot joint to shift a center of gravity of the head-mounted display to offset changes in torque about the pivot joint induced by the static mass center of gravity moving relative to the pivot joint.

In an upright position, the moving mass center of gravity may be rearward of the pivot joint, and the static mass center of gravity forward of the pivot joint.

In a forward position, the moving mass center of gravity may be rearward of the pivot joint, and the static mass center of gravity forward of the pivot joint.

As the head-mounted display is tilted forward about the pivot joint from the upright position to the forward position, the moving mass center of gravity may be moved from a first location away from the static mass center of gravity to a second location.

The first location may be forward of the pivot joint in the forward position. The moving mass may include a balancing mass and another balancing mass that may be moved in cooperation to shift the moving mass center of gravity rearward of the static mass center of gravity. The static mass further may further include a movement sensor that senses movement of the head-mounted display, and the moving mass is moved in response to the movement sensed by the movement sensor to shift the moving mass center of gravity to offset changes in torque induced by the static mass from the movement.

In an implementation, a method for operating a head-mounted display includes sensing, with a sensor, tilting of the head-mounted display, and shifting, with an actuator, a center of gravity of the head-mounted display relative to itself according to the sensing. The head-mounted display being configured to be worn on a head of a user and display graphical content to thereto.

Apple's patent FIG. 1 below is a side view of a head-mounted display on a head of a user, the head being shown in an upright position (solid lines) and in a tilted position (dashed lines); FIG. 2A is a schematic side view of the head-mounted display of FIG. 1 on the head of the user in the upright position and in a first configuration; FIG. 2B is a schematic side view of the head-mounted display of FIG. 1 on the head of the user in the tilted position and in the first configuration; FIG. 2C is a schematic side of the head-mounted display of FIG. 1 on the head of the user in the titled position and in a second configuration.

Referring to Apple's patent FIGS. 3 and 4, the balancing mass #130, which forms the moving mass M.sub.moving, is contemplated as being movable in different manners, for example, with different mechanisms or actuators, for example, being coupled to the balancing mass 130 and the head support 120. Those portions of the mechanisms that do not change position when operated may be considered part of the static mass M.sub.static. For example, an electric motor may have a rotor that rotates in place and, therefore, is considered part of the static mass M.sub.static.

As shown in FIG. 3 above, the balancing mass #130 may be movable by a lead screw mechanism #332 having a motor #334 and a lead screw #336 to which the balancing mass #130 is thread-ably coupled. As the motor  is operated (e.g., turned), the lead screw rotates and the balancing mass moves there-along. The lead screw mechanism may, for example, be coupled to the head support #120. Alternatively, the actuator may include a motor that itself forms the balancing mass (e.g., omitting the motor #334) and moves along the lead screw #336 relative to the display unit, for example, with the lead screw in turn being coupled to the head support.

As shown in FIG. 4 above, the balancing mass #130 may be movable by a belt drive mechanism #432 having a motor #434 and a belt #436 coupled to the balancing mass and operatively coupled to the motor to be moved thereby (e.g., via toothed engagement). As the motor is operated (e.g., turned), the belt is pulled thereby to, in turn, pull the balancing mass toward or away from the display unit. The balancing mass may be guided in a path, for example, along a track. The belt drive mechanism may, for example, be coupled to the head support.

For more details, review Apple's granted patent 11782480.