Ultra-thin AR Lens Total Reflection Design
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Solution Overview
Problem
Existing AR display technologies face challenges in achieving a thin and light form factor while maintaining optical performance and providing a large field of view, making it difficult to integrate compactness with see-through display capabilities.
Innovation Solution
The design of an ultra-thin lens comprising a primary lens, an intermediate lens, and a secondary lens, which utilizes total reflection and light splitting to reduce the number of optical surfaces, allowing for a thin and light profile while maintaining good optical performance, and is integrated with a micro-display panel for near-eye AR displays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If conventional AR display optical systems are used, then AR display functionality is achieved, but the device becomes thick and heavy
Solution Approach 1:
The patent combines multiple optical functions (imaging, reflection, light splitting) into an integrated ultra-thin lens assembly consisting of a primary lens, intermediate lens, and secondary lens. This merging of functions reduces the overall number of separate optical components and achieves a thickness of 8mm or less while maintaining AR display capabilities
Solution Approach 2:
The optical system is segmented into three distinct lens components (primary lens 10, intermediate lens 20, secondary lens 30) with specific functions assigned to each. The primary lens handles total reflection, the intermediate lens performs light splitting, and the secondary lens completes the optical path, allowing each component to be optimized independently for thinness and performance
2Length of moving object
If the lens thickness is reduced to achieve a thin profile, then wearability is improved, but optical performance may deteriorate
Solution Approach 1:
The patent employs free-form surfaces and aspherical surfaces instead of conventional spherical surfaces, fundamentally changing the geometric parameters of the optical surfaces. This allows for optimized light path control within the ultra-thin 8mm profile while maintaining imaging quality and optical performance
Solution Approach 2:
The patent replaces conventional multi-element optical systems with a novel ultra-thin lens design that uses total internal reflection and light splitting mechanisms. This substitution achieves the same optical functions with dramatically reduced thickness, proving that mechanical/optical performance is not compromised by the reduced dimension
3Area of stationary object
If the field of view is increased to provide a larger display area, then AR display capability is improved, but device complexity increases
Solution Approach 1:
The patent achieves a 40-degree field of view by utilizing three-dimensional free-form surface geometries and aspherical surfaces that control light paths in multiple dimensions. This dimensional approach allows for expanded field of view without proportionally increasing the physical size or complexity of the optical system
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
The ultra-thin lens achieves a thin and light profile, enabling comfortable wear like ordinary glasses, with a field of view of up to 40 degrees and a thickness of 8 mm or less, while maintaining effective AR display capabilities.
Implementation Method 1
the primary lens receives image light from a micro-display panel that is transmitted into the primary lens with the first optical surface (106) as an incident surface, propagates in a direction of the third optical surface (103), and then undergoes total reflection at the third optical surface (103) and the second optical surface (102) in sequence
Implementation Method 2
the fourth optical surface is provided adjacent to the third optical surface and has a predetermined gap therewith, the image light directed to the intermediate lens is transmitted into the intermediate lens through the fourth optical surface, and part of the image light is reflected by the fifth optical surface back to the intermediate lens
Data Source
AI summary
An ultra-thin lens for augmented reality (AR) display includes: a primary lens, an intermediate lens, and a secondary lens. After entering the primary lens, image light undergoes two total reflections, then enters the intermediate lens and is partially reflected, then is directed to a human eye through the intermediate lens and the primary lens. The secondary lens is configured on the other side of the intermediate lens, and environmental light is directed to the human eye through the secondary lens, the intermediate lens, and the primary lens. According to the ultra-thin lens, total reflection and light splitting functions of the image light are realized respectively through the primary lens and the intermediate lens, so that the entire lens has a thin and light profile.