Optical Waveguide Spectrum Sweeping to Suppress Newton Rings
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Optical waveguide arrangements in Head-Mounted Displays (HMDs) and Head-Up Displays (HUDs) suffer from interference patterns, such as Newton rings, which degrade the image quality.
Innovation Solution
The solution involves shaping the spectrum of the light signal by sweeping a distinct spectral characteristic, such as a peak wavelength, during the persistence time of vision of the human eye, effectively reducing the coherence length and visibility of interference patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If optical waveguide technology is used in HMDs and HUDs, then the display can be implemented, but interference patterns such as Newton rings appear which degrade image quality
Solution Approach 1:
The patent changes the temporal parameter of the light signal by sweeping its spectrum over time. Specifically, the central wavelength of the light signal is modulated to vary during the persistence time of vision, which reduces the coherence length and thereby suppresses interference patterns while maintaining display functionality
Solution Approach 2:
The patent applies periodic spectral sweeping of the light signal at a frequency that matches the persistence time of vision. This periodic modulation of the spectrum creates time-varying coherence properties that average out interference patterns over the integration time of the human eye
2Use of energy by moving object
If narrow spectral bandwidth light sources such as lasers are used, then the waveguide display can be implemented, but interference patterns become visible in the virtual image
Solution Approach 1:
The patent transforms the static spectral property of the light source into a dynamic one by continuously sweeping the spectrum during the persistence time of vision. This dynamic spectral modulation reduces the temporal coherence of the light while maintaining the energy efficiency of narrow bandwidth sources
Solution Approach 2:
The patent modulates the central wavelength parameter of the light signal over time, sweeping it across a range of wavelengths. This parameter change reduces the coherence length of the light source, thereby suppressing interference patterns while preserving the energy efficiency of laser sources
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
This approach significantly reduces the visibility of interference patterns, thereby enhancing the image quality produced by waveguide-based displays in HMDs and HUDs.
Implementation Method 1
shaping of a spectrum of the light signal during a period of time, said period of time corresponding to a persistence time of vision of the human eye
Implementation Method 2
the at least one optical waveguide is arranged to receive the light signal from the light source and to convey the light signal to a human eye
Data Source
AI summary
An optical waveguide arrangement comprising a light source arranged to transmit a light signal to at least one optical waveguide of the optical waveguide arrangement, the at least one optical waveguide, wherein the at least one optical waveguide is arranged to receive the light signal from the light source and to convey the light signal to a human eye, to generate a waveguide-based display and at least one processor configured to control the light source, wherein the at least one processor is configured to cause shaping of a spectrum of the light signal during a period of time, said period of time corresponding to a persistence time of vision of the human eye, wherein the at least one processor is further configured to cause shaping of a spectrum of the light signal between a first wavelength and a second wavelength during said period of time.