Head-worn Optical System Light Trap for Contrast
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Solution Overview
Problem
Current wearable computing systems face challenges in managing 'off' pixel light, achieving improved see-through transparency, image contrast, brightness, and sharpness, while also ensuring security compliance through eye imaging and access control.
Innovation Solution
The implementation of an optical system for head-worn computing that includes a DLP-based upper optical module with a light trap to absorb 'off' pixel light, a TIR wedge to redirect and trap dark state light, and a combiner element for enhanced see-through transparency, combined with eye imaging for security and access control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a DLP-based optical system is used to display images, then image display capability is improved, but 'off' pixel light causes reduced image contrast and quality
Solution Approach 1:
The patent extracts and removes the harmful 'off' pixel light from the optical path using dedicated light trap structures. These traps are positioned to intercept stray light before it reaches the user's eye, effectively separating the harmful light component from the useful image light.
Solution Approach 2:
The patent converts the potentially harmful stray light into a beneficial configuration by directing it through TIR (Total Internal Reflection) wedges that redirect the light into light trap regions. This transforms the problematic off-pixel light into a controlled optical path that ultimately gets absorbed, improving overall image quality.
2Illumination intensity
If see-through transparency is improved for environmental visibility, then transparency is improved, but image quality and contrast may deteriorate
Solution Approach 1:
The patent applies different optical properties to different regions of the combiner element. The combiner is designed to be highly transparent in the environmental light path while simultaneously reflecting and directing display light and stray light into appropriate optical paths, creating local quality variations that satisfy both transparency and contrast requirements.
3Measurement precision
If light trap structures are added to absorb stray light, then image contrast is improved, but device complexity increases
Solution Approach 1:
The patent merges the light trap structures with the existing optical components such as the combiner element and TIR wedges. Rather than adding separate, discrete light trap components, the absorption structures are integrated into the surfaces and interfaces of existing optical elements, reducing overall device complexity while maintaining contrast improvement.
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 solution enhances image quality by reducing stray light, improving contrast and brightness, and provides secure access control through effective eye imaging, ensuring a seamless user experience with enhanced see-through capabilities.
Implementation Method 1
a DLP-based upper optical module with a light trap to absorb 'off' pixel light
Implementation Method 2
a TIR wedge to redirect and trap dark state light
Data Source
AI summary
Aspects of the present invention relate to optical systems in head worn computing.