Head-worn Optical Modules Managing Off-Pixel Stray Light
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Solution Overview
Problem
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 development of optical systems for head-worn computing that include upper and lower optical modules with DLP technology, polarized light sources, and light traps to manage 'off' pixel light, combined with eye imaging systems for security and access control, allowing for compact and lightweight designs that enhance image quality and user interaction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If DLP technology is used to display images, then image brightness and contrast are improved, but 'off' pixel light causes reduced see-through transparency and image sharpness
Solution Approach 1:
The patent extracts and removes the harmful 'off' pixel light from the optical path by introducing dedicated light trap structures. These light traps are positioned to intercept stray light before it reaches the user's eye, effectively separating the useful image light from the harmful off-pixel light that would otherwise degrade see-through transparency and image sharpness.
Solution Approach 2:
The patent introduces intermediary optical elements including polarizing filters and wavelength-selective filters positioned between the DLP display and the user's eye. These intermediaries selectively transmit useful image light while blocking harmful stray light from off pixels, thereby resolving the contradiction between maintaining image brightness and eliminating stray light interference.
2Manufacturing precision
If light traps are added to manage off pixel light, then stray light is reduced and image sharpness is improved, but device complexity and size increase
Solution Approach 1:
The patent merges multiple functions into integrated optical elements. The light trap structures are designed to perform both stray light absorption and structural support functions. Additionally, polarizing filters and wavelength-selective filters are combined into single multi-functional optical components that reduce the overall number of separate elements needed in the system.
Solution Approach 2:
The patent implements a nested arrangement where light trap structures are positioned within the existing optical module housing. The filters and optical elements are nested within each other in a compact configuration, allowing the light management functions to be integrated within the constrained space of the head-worn device without significantly increasing overall size.
3Illumination intensity
If see-through transparency is improved for environmental viewing, then user awareness of surroundings is enhanced, but image contrast and brightness from the display are reduced
Solution Approach 1:
The patent applies local quality by using wavelength-selective filtering that differentiates between display light wavelengths and environmental light wavelengths. The optical system is optimized to transmit environmental visible light while selectively blocking specific wavelengths associated with display backlight, thereby maintaining both see-through transparency and display image contrast through spectral differentiation.
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
The solution effectively reduces stray light, provides high contrast and brightness, and enables secure access control by managing 'off' pixel light and integrating eye imaging, resulting in improved image quality and user experience while maintaining security compliance.
Implementation Method 1
light traps to manage 'off' pixel light
Implementation Method 2
polarized light sources
Data Source
AI summary
Aspects of the present invention relate to optical systems in head worn computing.