New Apple patents reveal a Lens Distant Test for Vision Pro / HMD systems and an XR Smartglasses Wave Guide Illumination Eye Assessment system and more published in the U.S. and Europe.
Lens Distance Test For Head-Mounted Display Devices
The simulated environments of VR and/or the mixed environments of MR may be utilized to provide an interactive user experience for multiple applications, such as applications that add virtual content to a real-time view of the viewer's environment, interacting with virtual training environments, gaming, remotely controlling drones or other mechanical systems, viewing digital media content, interacting with the Internet, or the like.
Apple's invention covers various embodiments of methods and apparatus for performing a lens distance test in head-mounted displays (HMDs), such as AR or VR headsets. The distance test is performed to determine the distance between a user's eye and a lens of the HMD (e.g. the display lens of the HMD or a clip-on lens).
In some embodiments, the HMD is configured to determine a current pose of the eye based on a series of captured eye images. The pose may be determined using a gaze tracking system implemented by the HMD, and is used by the HMD to determine the distance from the apex of the cornea to a closest point on the lens.
If the determined distance is too small or too large，an alert or notification is generated instructing the user to adjust the position of the HMD or change the light seal to achieve better distancing, so as to reduce the risk of eye injury and/or improve the user experience.
In some embodiments, the distance test may be repeated during a user session to reevaluate and/or monitor the lens distance.
In some embodiments, the HMD may include left and right optical lenses (e.g. display lenses) located between the display and the user's eyes. The distance between the user's eye (e.g. the cornea surface) and the display lens can have significant impacts on the user experience of the device.
For example, on VR and AR headsets, the best user experience is typically achieved when the user's eyes are within an optimal range of distances from the lens. Moreover, a lens distance that is too small can raise safety concerns, such as potential injuries to the cornea when the user experiences a fall.
In some embodiments, the lens distance test may be repeated during a user session of the HMD, for example, when the HMD is detected to have moved relative to the user's eyes, or according to a periodic retesting schedule.
In some embodiments, the lens distance test may be performed using a gaze tracking system included in the HMD for detecting the gaze direction of the user's eyes.
In some embodiments, the gaze tracking system may include at least one eye tracking camera (e.g., infrared (IR) or near-IR (NIR) cameras) positioned at each side of the user's face, and illumination sources (e.g., IR or NIR light sources such as an array or ring of LEDs) that emit light (e.g., IR or NIR light) towards the user's eyes.
The eye tracking cameras may be pointed towards the user's eyes to receive reflected IR or NIR light from the light sources directly from the eyes, or alternatively may be pointed towards “hot” mirrors located between the user's eyes and the display panels that reflect IR or NIR light from the eyes to the eye tracking cameras while allowing visible light to pass.
The gaze tracking system may determine a current pose of the user's eye, which may indicate the apex location of the cornea. In some embodiments, the distance from the apex location to a nearest point on the lens is used as the lens distance. If the lens distance is too short of too long (e.g. outside of a pre-specified threshold or range), the HMD will generate an alert to the user.
For full details, review Apple's patent application 20240105046 published on March 28, 2024 by the U.S. Patent Office.
Translated from: patentlyapple
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