Polarization Waveguide Near-Eye Display Field of View
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Solution Overview
Problem
Conventional near-eye display systems using total internal reflection (TIR)-based waveguides face limitations such as restricted field of view, increased weight, and cost due to the need for high-index materials, and are prone to contamination issues requiring complex sealing mechanisms.
Innovation Solution
The implementation of a polarization waveguide that manipulates light through multiple changes in polarization state rather than relying on TIR, allowing for the use of lower-index materials and enabling a wider field of view, lighter, and less expensive designs with non-parallel or curved surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional TIR-based waveguides use high-index materials to achieve total internal reflection, then light can be conveyed through the waveguide, but the field of view is restricted and the system becomes heavier and more expensive
Solution Approach 1:
The patent changes the fundamental parameter of light guidance from total internal reflection to polarization-based reflection. By using a stack of alternating high-index and low-index layers that reflect specific polarization states, the system achieves effective light conveyance without requiring the high-index materials needed for TIR, thereby expanding the field of view while maintaining guidance efficiency
Solution Approach 2:
The waveguide employs a composite layered structure with alternating high-index and low-index materials. This composite approach enables polarization-selective reflection at each interface, allowing the system to guide light through cumulative reflection effects rather than relying on a single high-index material for TIR, thus resolving the field of view limitation
2Reliability
If conventional TIR-based waveguides use high-index materials, then total internal reflection can be achieved, but the waveguide becomes heavier and more expensive
Solution Approach 1:
The invention fundamentally changes the light guidance mechanism from TIR to polarization-based reflection. By using a multilayer structure that reflects specific polarization states, the system achieves effective light guidance without requiring high-index materials, thereby reducing waveguide weight while maintaining guidance effectiveness
Solution Approach 2:
The patent substitutes the mechanical/optical mechanism of total internal reflection with a polarization-based reflection mechanism. This substitution allows the use of lighter materials since the guidance effect is achieved through the layered structure's optical properties rather than requiring high-index materials, thus reducing overall waveguide weight
3Reliability
If conventional TIR-based waveguides are sealed to prevent contamination, then light leakage is reduced, but the system complexity and cost increase
Solution Approach 1:
The patent extracts the requirement for sealing by eliminating the dependency on TIR. Since the polarization-based reflection mechanism does not require maintaining strict optical conditions at the waveguide surfaces, contamination and light leakage issues are resolved without complex sealing mechanisms, thereby reducing system complexity
Solution Approach 2:
The polarization-maintaining layered structure inherently protects against light leakage without requiring external sealing mechanisms. The optical design itself provides the protection needed, making the system self-sufficient and eliminating the need for additional sealing components, thus reducing complexity
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 enhances the field of view and reduces the weight and cost of near-eye display systems while eliminating the need for complex sealing, providing a more efficient and cost-effective solution for conveying display light to the user.
Implementation Method 1
conveying a representation of the display light from an in-coupling interface facing the display to an out-coupling interface facing an eye through multiple changes of the polarization state of the representative light as it traverses the polarization waveguide, where at least a subset of these changes in polarization state induce reflection of the representative light
Implementation Method 2
at least a subset of these changes in polarization state induce reflection of the representative light within the PWG
Data Source
Figure 1~2
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AI summary
A near-eye display system includes a polarization waveguide (102) having an in-coupling interface (316) disposed proximate to a first end and an out-coupling interface (318) disposed proximate to an opposite second end. The polarization waveguide is configured to convey light incident at the in-coupling interface to the out-coupling interface by inducing multiple changes in a polarization state of the light as the light traverses the polarization waveguide. At least a subset of the changes in polarization state induce the light to reflect within the polarization waveguide without relying on total internal reflection (TIR).