Apple reveals an aspect of their AR smartglasses optical system designed to reduce distortion & bulk of the glasses
Of late, there's been all kinds of speculation about Apple's first AR glasses product coming to market sometime over the next two years, including a bizarre rumor about a special Steve Jobs edition (with thin rounded lenses). Perhaps we'll see that by 2030 – but for now, it's a silly rumor fantasy. While those rumors were flying around yesterday, another optical system patent application from Apple was published by the US Patent & Trademark Office.
Apple's ramp up in patent applications for both a Head Mounted Display device and smartglasses along with accessories have been accelerating over the last year. There have been 23 patent related inventions revealed in the first five months of 2020 alone.
In Apple's patent application background published yesterday they note that a head-mounted device such as a pair of virtual reality or mixed reality glasses may have a display for displaying images for a user. An optical system can be used to direct image light from the display to the eyes of a user.
The process of using an optical system to provide images from a display to the eyes of a user in a head-mounted device has the potential to introduce image distortion.
Challenges may also arise in forming an optical system that is sufficiently compact to wear on the head of a user. If care is not taken, an optical system for an electronic device may be overly bulky and may not exhibit satisfactory optical performance.
Apple's invention covers next-gen Head-Mounted Devices and other electronic devices may be used for virtual reality and mixed reality (augmented reality) systems.
A head-mounted device such as a pair of augmented reality glasses that is worn on the head of a user may be used to provide a user with computer-generated content that is overlaid on top of real-world content. The real-world content may be viewed directly by a user through a transparent portion of an optical system.
The optical system may be used to route images from one or more-pixel arrays in a display system to the eyes of a user. A waveguide such as a thin planar waveguide formed from a sheet of transparent material such as glass or plastic or other light guide may be included in the optical system to convey image light from the pixel arrays to the user.
The display system may include reflective displays such as liquid-crystal-on-silicon displays, microelectromechanical systems (MEMs) displays, or other displays.
One of Apple's key focal points in this patent filing is on a head-mounted device with a pixel array. Apple notes that "A light source may illuminate the pixel array to produce image light. When illuminating the pixel array, light from the light source may pass through a prism. Reflected image light may pass through the prism to a multi-element lens.
The image light may pass through the multi-element lens and may be coupled into a waveguide using an input coupler such as a prism."
An output coupler such as a diffraction grating may couple the image light out of the waveguide and towards a user. The user may view the image light and may simultaneously observe real-world objects through the waveguide.
Apple's patent FIG. 2 below is a diagram of an illustrative optical system that provides image light from a display to a user; FIG. 5 is cross-sectional side view of an illustrative multi-element lens for an optical system.
While Apple's smartglasses invention doesn't introduce us to exciting features like "X-ray mode" or a special 'Cheat-mode" for students, it does show us that Apple is out to overcome the current overly bulky AR smartglasses designs available today.
More importantly, Apple's optical system revealed today is carefully being designed to deliver superior optical performance. The other cool stuff will come later on, to be sure.
Apple's patent application 20200159020 that was published yesterday by the U.S. Patent Office was filed back in Q4 2019 with related work going back to at least 2017.
For engineers wanting to delve into the finer points of this invention can do so by reviewing the full patent here. Considering that this is a patent application, the timing of such a product to market is unknown at this time.