AR Eyepiece Architecture With Dynamic Dimming for Artifact Light
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Solution Overview
Problem
Existing augmented reality (AR) systems face challenges in effectively reducing artifact image light while efficiently projecting desired image light, particularly in complex optical stacks with high refractive index and curved or tilted surfaces, where anti-reflective coatings are inadequate.
Innovation Solution
The use of dynamic dimmers positioned within the optical stack to adjust light intensity, synchronized with the projector, to reduce artifact image light by partially or completely dimming it during specific time intervals, while allowing world light to pass through.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If anti-reflective coatings are used on optical surfaces, then reflection losses are reduced, but artifact image light is not sufficiently reduced in complex optical stacks with high refractive index and curved or tilted surfaces
Solution Approach 1:
A dynamic dimmer is introduced as an intermediary element positioned within the optical stack between the optical engine and waveguide. This dimmer selectively attenuates artifact image light (ghost reflections) while allowing desired image light and world light to pass through, thereby resolving the insufficiency of anti-reflective coatings alone in eliminating harmful reflections from complex optical surfaces
2Object-affected harmful factors
If dynamic dimmers are used to reduce artifact image light, then artifact image light is significantly reduced, but world light intensity may be reduced
Solution Approach 1:
The dynamic dimmer operates in synchronization with the projector's operation cycles. During projector off-periods, the dimmer is configured to allow maximum world light transmission. During projector on-periods, the dimmer selectively attenuates artifact image light. This periodic operation ensures artifact reduction without compromising overall world light visibility
Solution Approach 2:
The dimmer's optical properties are made dynamically adjustable rather than fixed. The dimmer can change its light transmission characteristics in real-time based on operational conditions, enabling it to selectively block artifact light while preserving world light transmission during different time intervals
3Reliability
If complex optical stacks with high refractive index and curved or tilted surfaces are used, then optical performance is improved, but artifact image light increases
Solution Approach 1:
The dynamic dimmer serves as a mediator positioned within the complex optical stack, specifically placed to intercept ghost reflections generated by the high refractive index and curved/tilted surfaces. It attenuates these harmful reflections without interfering with the beneficial optical performance provided by the complex stack design
Solution Approach 2:
The system accepts the presence of artifact light as an inevitable byproduct of high-performance optical design, then uses the dynamic dimmer to convert this harmful effect into a manageable parameter. The dimmer selectively targets and attenuates only the artifact portions while preserving the desired optical performance characteristics
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
Significantly reduces artifact image light reaching the user's eye while maintaining efficient projection of desired image light, even in bright outdoor conditions, with minimal impact on world light.
Implementation Method 1
adjusting a first dimmer of the optical system positioned between the world side and the first eyepiece to reduce an intensity of the light associated with the first artifact image impinging on the first dimmer
Implementation Method 2
projecting light associated with a first virtual image onto a first eyepiece of the optical system, causing a portion of the light associated with the first virtual image to propagate toward the user side
Implementation Method 3
complex optical stacks with high refractive index and curved or tilted surfaces
Data Source
AI summary
Techniques for artifact mitigation in an optical system are disclosed. Light associated with a world object is received at the optical system, which is characterized by a world side and a user side. Light associated with a virtual image is projected onto an eyepiece of the optical system, causing a portion of the light associated with the virtual image to propagate toward the user side and light associated with an artifact image to propagate toward the world side. A dimmer of the optical system positioned between the world side and the eyepiece is adjusted to reduce an intensity of the light associated with the artifact image impinging on the dimmer and an intensity of the light associated with the world object impinging on the dimmer.