Near-Eye Array Optics for Switchable Focus and See-Through AR
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Solution Overview
Problem
Conventional near-eye displays struggle with focusing virtual images into the user's eye without obstructing the view of the real world, and they lack the ability to rapidly switch between virtual and real-world images.
Innovation Solution
A near-eye display utilizing a see-through display coupled with dynamic, switchable optics, including an array of light-emitting transparent pixels and switchable micro-lenses, which can focus and steer light to form virtual images, and rapidly switch between focusing and non-focusing states to combine virtual and real-world images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional imaging optics are used to focus virtual images, then the virtual image can be brought into focus, but the real world view is obstructed and rapid switching between virtual and real-world images is not possible
Solution Approach 1:
The patent employs dynamically switchable micro-lens arrays that can transition between focused and unfocused states on demand. This dynamic capability allows the system to switch between presenting virtual images and real-world views without mechanical movement, achieving both precise focusing when needed and rapid switching when transitioning between modes.
Solution Approach 2:
The micro-lens arrays change their optical parameters (focal length, focus state) electronically rather than mechanically. By altering the optical properties of the micro-lenses through electrical control, the system achieves precise focus for virtual images while maintaining the ability to rapidly switch between focused and unfocused states, resolving the contradiction between focus precision and switching speed.
2Adaptability or versatility
If an optical combiner is used to combine virtual and real-world light, then both images can be viewed simultaneously, but the device complexity and size increase
Solution Approach 1:
Instead of using a single complex optical combiner, the patent divides the optical system into multiple independent micro-lens arrays, each corresponding to individual pixels or pixel groups. This segmentation allows each micro-lens to independently control light paths for virtual and real-world images, simplifying the overall optical architecture while maintaining the capability to combine both image types simultaneously.
Solution Approach 2:
The micro-lens arrays serve multiple functions: they can focus light for virtual images, allow ambient light to pass through for real-world viewing, and switch between these modes rapidly. This multi-functionality eliminates the need for separate dedicated components for each function, reducing overall device complexity while maintaining adaptability.
3Volume of moving object
If the near-eye display is placed close to the eye for compactness, then the device size is reduced, but the eyebox and field of view are limited
Solution Approach 1:
The patent applies different optical properties to different regions of the display system through the micro-lens array configuration. Each micro-lens can be independently optimized for its specific location, allowing the system to maintain a compact form factor while expanding the effective eyebox area through localized optical control across the entire array.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables clear focusing of virtual images for individual optical prescriptions, allows simultaneous viewing of virtual and real-world images, and increases apparent pixel resolution through rapid focal point translation.
Implementation Method 1
an array of switchable micro-lenses focus the light so as to form a virtual image as perceived by a person wearing the near-eye display
Data Source
AI summary
Transparent organic light-emitting diodes (OLEDs) can be used as light-emitting pixels in a near-eye display for augmented reality applications. The light from these pixels can be switchably tuned and/or steered with tunable beam-steering and focusing elements, also called tunable micro-lenses. These tunable micro-lenses are arranged in an array and mated to the array of pixels, for example, by embedding in a spectacle lens. The tunable micro-lenses use fast-switching half-wave plates to selectively focus and/or tilt light from the pixels. By switching the light from the pixels between resolvable positions/angles at a rate faster than the flicker fusion threshold (e.g., 60 Hz), the tunable micro-lenses can effectively double the apparent resolution of the near-eye display. And by switching between focusing and non-focusing states at the same rate, the tunable micro-lenses can effectively superimpose the virtual images from the pixels on the real-world image visible through the pixels.