Gradient Tint Lens for AR Rainbow Artifact Reduction
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Solution Overview
Problem
Conventional augmented reality systems cause eye fatigue and discomfort due to the vergence-accommodation conflict, and they often produce unintended rainbow artifacts from in-coupled real-world light, disrupting the AR experience.
Innovation Solution
An augmented reality system with a light-guiding optical element and a gradient tinted lens that absorbs and transmits real-world light to minimize rainbow artifacts, allowing for comfortable 3D perception by reducing ambient light and maintaining interaction with the physical environment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a light-guiding optical element is made transparent to real-world light to maintain AR experience, then virtual content visibility is improved, but rainbow artifacts increase due to in-coupled real-world light
Solution Approach 1:
The patent applies a gradient tint to the lens that varies in strength across different regions. The tint is stronger at the top portion where overhead light sources are most likely to enter the optical element and causes rainbow artifacts, while being weaker or absent at the bottom portion to maintain visibility of virtual content. This local variation in tint strength selectively reduces harmful light while preserving useful light transmission.
Solution Approach 2:
The patent uses a gradient tint coating that changes the optical properties of the lens across its surface. The tint absorbs specific wavelengths of light (typically red and blue) more strongly at the top portion, creating a color filtering effect that reduces rainbow artifacts. The gradient nature means the filtering strength varies continuously across the lens, optimizing both artifact reduction and content visibility.
2Object-generated harmful factors
If overhead light is blocked to minimize rainbow artifacts, then virtual content quality improves, but field of view illumination decreases
Solution Approach 1:
The gradient tint is positioned and configured to primarily affect the top portion of the field of view where overhead light sources are most problematic. The bottom portion of the lens maintains higher transparency to preserve illumination of the field of view from other light sources. This spatial differentiation allows selective light management.
Solution Approach 2:
The patent changes the optical parameters (transmission, absorption, refraction) of the lens in a gradient manner across its surface. By varying the tint concentration and optical density from top to bottom, the system achieves different light transmission characteristics in different regions, optimizing both artifact reduction and overall illumination.
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 system effectively reduces eye fatigue and discomfort by minimizing rainbow artifacts and enhancing virtual content solidity, providing a more comfortable and immersive AR experience.
Implementation Method 1
the virtual light beam enters the light guiding optical element, propagates through the light guiding optical element by total internal reflection (TIR)
Implementation Method 2
the lens is configured with a tint that absorbs an amount of real-world light to allow a portion of the real-world light to transmit through the light guiding optical element
Data Source
AI summary
An augmented reality system includes a light source configured to generate a virtual light beam. The system also includes a light guiding optical element, the light guiding optical element is transparent to a first real-world light beam, wherein the virtual light beam enters the light guiding optical element, propagates through the light guiding optical element by total internal reflection (TIR) and exits the light guiding optical elements. The system also includes a lens disposed adjacent and exterior to the surface of the light guiding optical element. The lens is configured with a gradient tint that transmits less real-world light at a world side top portion of the lens and transmits more real-world light at a world side bottom portion of the lens, wherein rainbow artifacts, generated from inadvertent diffraction of the overhead real-world light by the light guiding optical element, is minimized.