Multi-focal AR Lenses with Segmented Reflective Surfaces
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Solution Overview
Problem
In virtual and augmented reality applications, particularly with head-mounted displays, users face challenges in focusing between virtual and real-world objects at different distances, as existing technologies cannot adequately compensate for the overlay of virtual objects with physical objects, leading to constant eye refocusing.
Innovation Solution
The development of multi-focal lenses with reflective inside surfaces, divided into portions that focus virtual images at different virtual distances, allowing users to seamlessly view both near and far objects without affecting real-world optics, using a design that varies lens power across the surface through 'oxels' to create a free space reflective optical system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the optical position of virtual objects is fixed at one particular distance, then the virtual objects can be displayed clearly at that distance, but the user cannot comfortably view both near and distant virtual objects without constant refocusing
Solution Approach 1:
The lens is divided into multiple zones, each with different optical powers corresponding to different virtual distances. The lens includes a first zone for near virtual objects, a second zone for distant virtual objects, and intermediate zones for transition, allowing users to view virtual objects at multiple distances simultaneously without refocusing
Solution Approach 2:
Different portions of the lens are assigned different optical properties (focal lengths) to serve different viewing purposes. The lens power varies locally across the lens surface, with each region optimized for specific virtual object distances, enabling multi-focal functionality in a single optical element
2Adaptability or versatility
If the lens is designed to focus virtual objects at multiple distances, then the user can view both near and distant virtual objects, but the lens structure becomes more complex
Solution Approach 1:
Multiple optical functions (different focal lengths for near, intermediate, and distant viewing) are merged into a single lens element. The multi-focal lens integrates what would traditionally require multiple separate lenses or complex adjustable mechanisms into one monolithic optical component with spatially varying focal properties
3Device complexity
If conventional single-focal lenses are used, then the lens structure remains simple, but the user experiences eye strain from constant refocusing between virtual and real objects
Solution Approach 1:
The lens provides dynamic optical accommodation by incorporating multiple fixed focal zones that correspond to different virtual object distances. This allows the optical system to adapt to different viewing scenarios without requiring active adjustment mechanisms, delivering dynamic multi-focal capability in a passive optical element
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 users to comfortably interact with both virtual and real-world objects by maintaining clear focus on virtual objects at intended distances, reducing eye strain and improving usability in augmented reality applications by allowing focus on nearby and distant objects without changing real-world optics.
Implementation Method 1
a reflective inside surface having a first inside surface portion having an optical surface which focuses an incident beam of a first image
Implementation Method 2
an optical surface which focuses an incident beam of a first image so that objects in the first image appear at a first virtual distance
Data Source
AI summary
A lens includes a reflective inside surface including a first inside surface portion having an optical surface which focuses an incident beam of a first image so that objects in the first image appears at a first virtual distance, and at least a second inside surface portion having an optical surface which focuses an incident beam of a second image so that objects in the second image to appear at a second virtual distance that is further than the first virtual distance. The lens is a passive lens. The lens can be used in an optical see-through head mounted display (HMD) apparatus to allow a user of the HMD to focus on nearby virtual objects coming from the first inside surface portion while viewing nearby external-world objects and to focus on more distant virtual objects coming from the second inside surface portion while viewing more distant external-world objects.