Reflective Circular Polarizer for Folded Near-Eye Display
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Solution Overview
Problem
Existing near-eye display systems face limitations due to the cost, size, weight, limited field of view, and poor efficiency of optical systems used to relay images in augmented reality applications.
Innovation Solution
A folded optical system incorporating a reflective circular polarizer made of cholesteric liquid crystal (CLC) is used to replace traditional polarizers and wave plates, allowing for efficient polarization state conversion and alignment-free operation, enabling compact and efficient image relay in near-eye displays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional reflective linear polarizer and wave plate are used, then polarization state conversion is achieved, but alignment precision and device complexity are worsened
Solution Approach 1:
The patent combines the functions of the reflective linear polarizer and wave plate into a single reflective circular polarizer component. This merged component performs both polarization conversion and phase retardation in one element, eliminating the need for separate components and their precise alignment, thus reducing device complexity while maintaining reliable polarization state conversion.
Solution Approach 2:
The reflective circular polarizer serves multiple functions simultaneously: it acts as a polarizing element, a phase retarder, and a beam splitter. This multi-functionality replaces what previously required multiple separate components, simplifying the overall optical system while ensuring robust polarization control without alignment sensitivity.
2Reliability
If traditional optical system is used, then image relay is achieved, but size and weight are worsened
Solution Approach 1:
The patent merges multiple optical functions into fewer components, particularly using the reflective circular polarizer to combine polarization control and beam splitting. This reduction in component count directly decreases the overall weight of the near-eye display system while maintaining effective image relay functionality.
3Reliability
If traditional optical system is used, then image relay is achieved, but compactness is worsened
Solution Approach 1:
By combining multiple optical functions into single components like the reflective circular polarizer, the patent reduces the number of separate elements required for image relay. This consolidation shrinks the overall volume of the optical system, making it more compact and suitable for near-eye display applications.
4Reliability
If traditional optical system is used, then image relay is achieved, but efficiency is worsened
Solution Approach 1:
The patent extracts and eliminates unnecessary optical components from the traditional image relay system. By removing redundant elements and using the reflective circular polarizer's inherent properties, the system reduces light loss and improves overall optical efficiency while maintaining reliable image relay.
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 enhances the efficiency and compactness of near-eye display systems by effectively folding light paths, improving image quality and field of view while reducing the need for precise alignment of optical components.
Implementation Method 1
The reflective circular polarizer can be made using, for example, cholesteric liquid crystal (CLC). The reflective circular polarizer may include liquid crystal molecules arranged in a helical structure.
Implementation Method 2
A reflective circular polarizer (CP) may be used in a folded optical system... The reflective circular polarizer can reflect circularly polarized light while keeping the handedness of the reflected light the same as that of the incident light.
Implementation Method 3
a second polarizer configured to transmit light of a second circular polarization state and reflect light of the first circular polarization state... a partial reflector positioned between the first polarizer and the second polarizer, where the partial reflector may be configured to transmit light from the first polarizer and reflect light from the second polarizer.
Data Source
AI summary
Techniques disclosed herein relate to folded optical systems for near-eye display. In one embodiment, an optical device includes a first polarizer, a second polarizer, and a partial reflector positioned between the first polarizer and the second polarizer. The first polarizer is configured to polarize incident light into light of a first circular polarization state. The second polarizer is configured to transmit light of a second circular polarization state and reflect light of the first circular polarization state without changing its polarization state. The partial reflector is configured to transmit light from the first polarizer, and reflect light from the second polarizer. The light reflected by the partial reflector and the light from the second polarizer have different polarization states.