Waveguide Display Dimming With Upconversion Photochromic Tinting
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Solution Overview
Problem
Current AR displays face challenges in dynamically adjusting brightness levels to match varying ambient environments, leading to issues such as low contrast, battery drain, and overheating, especially when used in bright or dark conditions.
Innovation Solution
A dimmable optical element comprising up-converting nanoparticles and a photochromic material that changes color in response to infrared light, allowing for dynamic dimming or tinting of XR displays, either entirely or locally, using internal or external light sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the display brightness is increased to improve visibility in bright environments, then the contrast between digital images and ambient environment is improved, but battery life is drained quickly and overheating occurs
Solution Approach 1:
The patent segments the optical path into multiple layers: a waveguide layer for displaying images and a separate dimmable optical element layer for controlling ambient light. This segmentation allows independent control of display brightness and ambient light dimming, enabling the display to maintain high brightness for visibility while the dimmable element reduces overall light transmission to prevent overheating and conserve battery life.
Solution Approach 2:
The patent introduces a dimmable optical element as an intermediary between the external environment and the user's eyes. This intermediary selectively dims ambient light before it reaches the user, improving contrast without requiring the display itself to reduce brightness. The optical element acts as a mediator that manages light transmission dynamically based on environmental conditions.
2Illumination intensity
If a fixed tinted lens is added to increase contrast in bright environments, then the contrast of digital images is improved, but the device cannot be used effectively in less bright environments
Solution Approach 1:
The patent employs a dynamic optical element that can change its light transmission properties in real-time. The optical element transitions from a fixed-tint approach to a dynamic system that adjusts its dimming level based on ambient light conditions. This allows the device to adapt to varying environments - providing strong dimming in bright sunlight and minimal or no dimming in indoor or low-light settings, thereby maintaining versatility across different usage scenarios.
Solution Approach 2:
The patent changes the optical parameters of the optical element dynamically. The optical element's light transmission parameter is adjusted based on environmental brightness conditions. In bright environments, the optical element transitions to a state with lower light transmission to enhance contrast. In less bright environments, it transitions to a state with higher light transmission, preserving visibility and usability across diverse conditions.
3Ease of operation
If a pixelated liquid crystal display is used to dim ambient light, then local dimming is achieved, but the device becomes complicated and expensive to fabricate
Solution Approach 1:
The patent extracts the dimming function from the complex pixelated liquid crystal display system and implements it through a simpler optical element integrated with the waveguide. Instead of using a full pixelated LCD structure requiring transparent electrodes and conduction lines, the invention uses a dimmable optical element that can be applied as a coating or integrated layer on the waveguide, significantly simplifying fabrication while maintaining local dimming capability through spatially selective activation.
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 effective contrast adjustment between XR objects and their surroundings by selectively dimming or tinting specific display portions, improving user experience across varying brightness conditions without significant power consumption or heat issues.
Implementation Method 1
the plurality of upconverting nanoparticles to emit light of a second energy level higher than the first energy level
Implementation Method 2
the photochromic material absorbs the light of the second energy level to cause the change in color of the at least a portion of the display
Data Source
AI summary
Systems, methods and apparatuses are described for dimming one or more portions of an extended reality (XR) display. Control circuitry may be configured to generate for display, at the display, an XR object. A dimmable optical element may comprise a plurality of up-converting nanoparticles and a photochromic material, and is configured to cause a change in color of at least a portion of the display. The dimmable optical element may be irradiated with light of a first energy level which causes the plurality of upconverting nanoparticles to emit light of a second energy level higher than the first energy level. The photochromic material may absorb the light of the second energy level to cause the change in color of the at least a portion of the display.