Improved color uniformity in monochrome holographic waveguide based near eye displays

Area of Science:

• Optics and Photonics
• Display Technology
• Holography

Background:

• Near-eye displays (NEDs) require high color uniformity across a wide field of view (FOV).
• Volume holographic gratings (VHGs) used in NEDs have limited FOV and cause color dispersion due to angular selectivity.
• Color variations in displayed images degrade visual experience.

Purpose of the Study:

• To enhance the field of view (FOV) and improve color uniformity in NEDs.
• To overcome the limitations of conventional VHGs in display applications.
• To enable precise and consistent color output for advanced visual systems.

Main Methods:

• Designing Bragg-matched, reflection-type, angular multiplexed VHGs.
• Utilizing numerical simulations to analyze spectral bandwidth and FOV.
• Conducting experimental measurements using spectroradiometers.

Main Results:

• Reduced spectral bandwidth from 42.7 nm to 14.7 nm over a 24° FOV using 3x multiplexed holographic couplers.
• Experimentally measured FOV of approximately 25.3°.
• Significant reduction in red (47.8% to 0%) and blue (20.6% to 8.5%) spectral contributions, improving color uniformity.

Conclusions:

• The developed multiplexed VHG method significantly improves color uniformity and expands FOV for NEDs.
• This approach offers a viable solution for high-performance display applications.
• Experimental validation confirms superior color consistency compared to conventional methods.