Earlier today Patently Apple discovered a patent application from Apple that was published this week in Europe. The patent application relates to optical systems and, more particularly, to optical systems for head-mounted devices. While the patent does indeed cover a traditional headset device for watching movies and playing VR games, much of the patent's emphasis is on smartglasses that could apply a user's prescription to light weight glasses used for mixed reality imagery.

Head-mounted devices such as virtual reality glasses and augmented reality glasses use displays to generate images and use lenses to present the images to the eyes of a user. If care is not taken, a head-mounted device may be cumbersome and tiring to wear. Optical systems for head-mounted devices may be bulky and heavy and may not be sufficiently adjustable. Extended use of a head-mounted device with this type of optical system may be uncomfortable. Apple's invention is to overcome these negative factors.

Apple's invention covers a head-mounted display device that may include a display system and an optical system in a housing. The display system may have displays that produce images.

Positioners may be used to move the displays relative to a user's eyes.   The positioners may be used to adjust the horizontal separation of the displays from each other to accommodate differences in interpupillary distance between users, may be used to make vertical display location adjustments to accommodate differences in facial anatomy between users, and may be used in adjusting eye-to-display spacing to alter focus.

The optical system may include tunable lenses such as tunable cylindrical liquid crystal lenses. The displays may be viewed through the lenses.  The optical system may include fixed spherical lenses that are used in conjunction with the tunable cylindrical lenses.

A sensor may be incorporated into the head-mounted device (HMD) to measure refractive errors in the user's eyes.  Viewing comfort may be enhanced by adjusting display position relative to the eye positions of the user's eyes and/or by adjusting lens settings based on the content being presented on the display and/or based on measured eye refractive errors.

The sensor may include waveguides and volume holograms and a camera for gathering light that has reflected from the retinas of the user's eyes.

Refractive errors such as farsightedness, nearsightedness, and astigmatism may be corrected by tuning the lenses and/or adjusting display positions.

Head-mounted devices such as head-mounted displays may be used for virtual reality and augmented reality systems.  For example, a pair of virtual reality glasses that is worn on the head of a user may be used to provide a user with virtual reality content. An illustrative system in which a head-mounted device such as a pair of virtual reality glasses is used in providing a user with virtual reality content is shown in FIG. 1 below.

As shown in FIG. 1 above, head-mounted display #10 may include a display system such as display system #40 that creates images and may have an optical system such as optical system #20 through which a user (see, e.g., user's eyes #46) may view the images produced by display system in direction #48.

The display system may be based on a liquid crystal display, an organic light­ emitting diode display, a display having an array of crystalline semiconductor light-emitting diode dies, a liquid-crystal-on-silicon display, a microelectromechanical systems (MEMs) display, and/or displays based on other display technologies.  Separate left and right displays may be included in system #40 for the user's left and right eyes or a single display may span both eyes.

Visual content (e.g., image data for still and/or moving images) may be provided to display the system using control circuitry #42 that is mounted in the head-mounted device and/or control circuitry that is mounted outside of head-mounted device (e.g., in an associated portable electronic device, laptop computer, or other computing equipment).

The control circuitry may include storage such as hard-disk storage, volatile and non-volatile memory, electrically programmable storage for forming a solid-state drive, and other memory.  It may also include one or more microprocessors, microcontrollers, digital signal processors, graphics processors, baseband processors, application-specific integrated circuits, and other processing circuitry.  

Communications circuits in the control circuitry may be used to transmit and receive data (e.g., wirelessly and/or over wired paths).  It may also use the display system to display visual content such as virtual reality content (e.g., computer-generated content associated with a virtual world), pre-recorded video for a movie or other media, or other images.

Next, input-output devices #44 of FIG. 1 may be coupled to control circuitry and may be used to gather user input from a user, may be used to make measurements on the environment surrounding the head mounted display device and may be used to provide output to a user, and/or be used to supply output to external electronic equipment.  Input-output devices may include buttons, keypads, keyboard keys, touch sensors, track pads, displays, touchscreen displays, microphones, speakers, light-emitting diodes for providing a user with visual output, and sensors (e.g., force sensors, temperature sensors, magnetic sensor, accelerometers, gyroscopes, and/or other sensors for measuring orientation, position, and/or movement of glasses, proximity sensors, capacitive touch sensors, strain gauges, gas sensors, pressure sensors, ambient light sensors, and/or other sensors). 

If desired, input­ output devices may include a sensing system that measures the eye characteristics of the user's eyes.  For example, a wavefront sensor such as a Shack-Hartmann wavefront sensor, Tscherning sensor, or a ray tracing sensor may be used to measure refractive errors in a user's eyes such as astigmatism, farsightedness, and nearsightedness. 

Devices input can also include cameras (digital image sensors) for capturing images of the user's surroundings, cameras for performing gaze detection operations by viewing eyes, and/or other cameras.

Apple's patent FIG. 2 presented below is a diagram of an illustrative head mounted device with adjustable displays and lenses.

Housing 12 of FIG. 2 above may have the shape of a frame for a pair of glasses (e.g., head-mounted device 10 may resemble eyeglasses), may have the shape of a helmet (e.g., head-mounted device 10 may form a helmet-mounted display), may have the shape of a pair of goggles, or may have any other suitable housing shape that allows housing to be worn on the head of a user.

The HMD housing may be formed from plastic, metal, fiber-composite materials such as carbon-fiber materials, wood and other natural materials, glass, other materials, and/or combinations of two or more of these materials.

Apple's patent FIG. 6A below is a diagram of an illustrative Shack-Hartmann sensor for a head-mounted device; FIGS. 6B, 6C, and 6D are diagrams of alternative light sources for the Shack­ Hartmann sensor.

Apple's patent FIG. 6B illustrated above shows us a configuration of an aspheric lens pair 77A collimating light (#74) from an LED source (#73).

In FIG. 6C, collimation optics assembly (#71) may contain just an LED (#73) and compound parabolic concentrator (# 77B). By sitting at the focus of the hollow parabolic mirror (#77C), light (#74) can be collected and collimated.

In FIG. 6D, the assembly (#71) may contain a lens array pair (#77C) and condenser lens (#79).

Input and output couplers such as volume holograms or other holographic couplers may be used in coupling light into and out of the ends of waveguides in FIG. 6A (#84 and #94).  The couplers are directional, meaning that light can enter the volume hologram in one direction.

Later into the patent filing, Apple notes that "the user input includes an eyeglasses prescription and the control circuitry is configured to adjust a position of the display with the positioner based on the eyeglasses prescription."

Apple's patent application was originally filed back in May 2018 and published in Europe on November 22, 2018. Considering that this is a patent application, the timing of such a product to market is unknown at this time.