Lightguide Optical Combiner for Headwearable Display Eye Box
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Solution Overview
Problem
Conventional head wearable displays face limitations due to the cost, size, weight, field of view, and efficiency of their optical systems, which restrict their practical and leisure applications.
Innovation Solution
The integration of a total internal reflection (TIR) based lightguide and optical combiner into an eyepiece for head wearable displays, which uses a lightguide component with a see-through add-on component to transport display light from a peripheral location to the user's central vision, combining it with ambient scene light to provide a large eye box and efficient optical system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If conventional optical systems are used in HMDs, then the basic display function is achieved, but the field of view, eye box size, and optical efficiency are limited
Solution Approach 1:
The patent combines the lightguide component and optical combiner into a single integrated eyepiece assembly. The lightguide transports display light from a peripheral location while the optical combiner combines it with ambient scene light, merging multiple optical functions into one compact structure that increases eye box size without proportionally increasing system complexity
Solution Approach 2:
The optical system uses total internal reflection at angled surfaces within the lightguide to redirect light from a peripheral location to the user's central vision. This dimensional redirection of light paths enables a larger effective eye box by utilizing three-dimensional optical routing rather than simple planar optics
2Volume of moving object
If the optical system is made more compact, then the size and weight are reduced, but the field of view and eye box may be compromised
Solution Approach 1:
The lightguide component uses total internal reflection at angled surfaces to redirect display light from a peripheral location around corners and through the lightguide to the viewing position. This three-dimensional light routing enables a compact physical footprint while maintaining an enlarged field of view and eye box through clever spatial arrangement of optical paths
Solution Approach 2:
The optical combiner is integrated within or alongside the lightguide structure, with the display light path nested within the same optical assembly that also handles ambient light. This nesting of optical functions within a compact volume achieves both miniaturization and preserved field of view
3Adaptability or versatility
If a larger eye box is provided to accommodate inter-pupillary deviations, then the adaptability is improved, but the optical system complexity increases
Solution Approach 1:
The integrated lightguide and optical combiner design provides a large eye box through combined optical functions. The lightguide's total internal reflection surfaces and the combiner's optical elements work together in a unified structure that naturally accommodates larger inter-pupillary deviations without requiring additional adjustment mechanisms or complex multi-component assemblies
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 the field of view and user experience by providing a large eye box that accommodates larger inter-pupillary deviations, while achieving high optical efficiency and allowing for both see-through and non-see-through versions, enabling improved augmented reality displays.
Implementation Method 1
The integration of a total internal reflection (TIR) based lightguide and optical combiner into an eyepiece for head wearable displays
Implementation Method 2
combining it with ambient scene light to provide a large eye box and efficient optical system
Data Source
AI summary
An eyepiece for a head wearable display includes a lightguide component for guiding display light and emitting the display light along at a viewing region. The light guide component includes an input surface oriented to receive the display light into the lightguide component at the peripheral location, a first folding surface disposed to reflect the display light received through the input surface, a second folding surface disposed to reflect the display light received from the first folding surface, an eye-ward facing surface disposed opposite to the second folding surface to reflect the display light received from the second folding surface, and a curved reflective surface having reflective optical power disposed at the viewing region to receive the display light reflected from the eye-ward facing surface and to reflect the display light for emission out through the eye-ward facing surface.