Wearable Display Angular Film for Rainbow Artifact Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Wearable display systems suffer from light transmission artifacts due to ambient light being diffracted into the user's field of view by grating structures, which diminish the user's experience.
Innovation Solution
Incorporation of an angularly selective film comprising polarization adjusting elements that vary light transmission based on the angle of incidence, using polarizers and birefringent materials to reduce transmission of light at high angles while maintaining transmission at small angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If diffractive structures are used to project volumetric images, then image depth and three-dimensional visualization are improved, but light transmission artifacts and rainbow effects increase
Solution Approach 1:
The patent divides the optical system into multiple functional layers: diffractive structures for image projection, angularly selective films for artifact reduction, and polarizing layers for light control. Each layer performs a specific function, allowing the system to maintain volumetric imaging capabilities while suppressing unwanted light artifacts through coordinated operation of segmented optical components
Solution Approach 2:
Angularly selective films and polarizing layers serve as intermediary elements between the diffractive structures and the user's eye. These intermediaries selectively filter ambient light at high angles before it reaches the user, reducing rainbow effects and artifacts while preserving the intended volumetric image projection
2Object-affected harmful factors
If angularly selective films are added to reduce artifacts, then light transmission control is improved, but device complexity increases
Solution Approach 1:
The patent employs thin-film angularly selective layers that can be laminated onto existing waveguide or eyepiece structures. These flexible thin films provide artifact reduction functionality without requiring substantial structural changes or bulky components, thereby limiting the increase in device complexity
Solution Approach 2:
The optical system integrates composite structures combining diffractive materials, angularly selective films, and polarizing layers. These composite materials are designed to work together synergistically, providing multiple functions (image projection, artifact reduction, light control) within a unified optical assembly that manages overall system complexity
3Adaptability or versatility
If polarizers and polarization adjusting elements are used, then transmission control at different angles is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent incorporates pre-aligned polarizing layers and angularly selective films during the manufacturing process. These components are pre-oriented to work with the diffractive structures, and alignment features or registration marks are built into the design to guide proper positioning during assembly, reducing the precision burden on final assembly operations
Solution Approach 2:
The patent optimizes the optical parameters of the polarizing layers and angularly selective films, such as their angular selectivity characteristics and transmission properties. By carefully selecting these parameters during the design phase, the system achieves effective artifact reduction with more relaxed manufacturing tolerances, as the optimized parameters provide greater tolerance to alignment variations
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 undesirable optical artifacts such as rainbow effects without impairing the user's view, by attenuating ambient light at high angles of incidence while preserving image clarity.
Implementation Method 1
the polarization adjusting film rotates a polarization state of light transmitted by a first of the pair of linear polarizers on the world side of the polarization adjusting film. An amount of rotation of the polarization state can vary depending on an angle of incidence of light transmitted by the first of the pair of linear polarizers
Implementation Method 2
the linear polarizers and polarization adjusting film significantly reduces transmission of visible light incident on the angularly selective film at large angles of incidence without significantly reducing transmission of light incident on the angularly selective film at small angles of incidence
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3C
AI summary
A wearable display system includes an eyepiece stack having a world side and a user side opposite the world side, wherein during use a user positioned on the user side views displayed images delivered by the system via the eyepiece stack which augment the user's view of the user's environment. The wearable display system also includes an angularly selective film arranged on the world side of the of the eyepiece stack. The angularly selective film includes a polarization adjusting film arranged between pair of linear polarizers. The linear polarizers and polarization adjusting film significantly reduces transmission of visible light incident on the angularly selective film at large angles of incidence without significantly reducing transmission of light incident on the angularly selective film at small angles of incidence.