On Thursday, the U.S. Patent and Trademark Office officially published a patent application from Apple that relates to possible future lens modules for HMDs (future Vision Pro and Smartglasses) that include a tunable lens with an adjustable spherical power, cylindrical axis, and/or cylindrical power.

This could be a game changer if Apple could pull this off as it would allow customers with prescription glasses to skip the use of expensive Zeiss lenses and more. This appears to be a major project at Apple as we've covered several patents on this one theme: 01, 02, 03, 04 and more. The concept is being pursued by other OEMs such as Xiaomi who produced the promotional/conceptual view regarding "Liquid Lenses."

ScienceDirect has an article on HMDs with Liquid Lenses here. Their abstract states that "An optical design for an immersive head-mounted display (HMD) with a liquid lens is described. This design combines the liquid lens with an immersive HMD system to improve the image quality for myopic and hyperopic users. A penta-prism is also incorporated and used to change the direction of the optical path to improve any optical aberration caused by the gravity effect."

Apple notes in their patent background that HMDs typically include lenses with fixed shapes and properties. If care is not taken, it may be difficult to adjust these types of lenses to optimally present content to each user of the head-mounted device.

User Interfaces For Adjusting A Tunable Lens

Apple's patent covers HMDs that may include a display that is configured to present at least one target, a gaze detection sensor configured to determine a point of gaze, and a tunable lens through which the display is viewable. The tunable lens may be configured to set an optical power based on the point of gaze relative to the at least one target. This is Apple's most extensive patent on this technology to date.

An electronic device may include a display configured to present an image through a masking layer with a ring of pinhole pairs, a tunable lens through which the display is viewable, and an input device configured to receive user input regarding a perceived image associated with the display and the masking layer.

A method of operating an electronic device with a display, a tunable lens that is aligned with the display, and a gaze detection sensor may include presenting multiple targets associated with respective spherical powers using the display, adjusting a spherical power of the tunable lens based on a point of gaze that is obtained using the gaze detection sensor, and receiving user input that identifies a preferred target of the multiple targets.

In some cases, the user may wish to view real-world content rather than a display. The user may require different optical prescriptions depending on the distance to an object, the degree to which the user's eyes are verging (which may be related to the distance to the object viewed), lighting conditions, and/or other factors. The head-mounted device may contain lenses disposed in such a way as the real-world content is viewable through the lens system.

The lens modules in the head-mounted device may include lenses that are adjustable such as fluid-filled adjustable lenses (hence 'Liquid lenses').

Apple's patent FIG. 2 illustrates a portion of a HMD. Each optical module #70 illustrated includes a corresponding lens module #72 (sometimes referred to as lens stack-up #72, lens #72, or adjustable lens #72).

Apple's patent FIG. 3 above is a cross-sectional side view of an illustrative lens module with multiple lens elements. As shown, lens module #72 includes a first lens element #72-1 and a second lens element #72-2. Each surface of the lens elements may have any desired curvature. One or both of lens elements #72-1 and #72-2 may be adjustable.

In one example, lens element #72-2 is a fixed (e.g., non-adjustable) lens element whereas lens element #72-1 is an adjustable lens element. The adjustable lens element 72-1 may be used to accommodate a user's eyeglass prescription, for example. The shape of lens element 72-1 may be adjusted if a user's eyeglass prescription changes (without needing to replace any of the other components within device 10A).

To review the full details of this invention, check out patent application 20240302657 filed for in January 30, 2024 and published on September 12, 2024. The lead inventor is noted as Gareth Hastings, Vision and Optics Scientist.