CLC See-Through AR Display for Clear Optics and Wide Field of View
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Solution Overview
Problem
Existing augmented reality (AR) and virtual reality (VR) headsets struggle to provide high-quality virtual content while maintaining clear see-through transparency, as existing steering elements often reflect or diffract out-of-band wavelengths, leading to reduced clarity and field of view.
Innovation Solution
The use of cholesteric liquid crystal (CLC) layers with controlled birefringence and spatially tuned chiral pitch to selectively reflect or transmit light based on polarization, allowing high-efficiency display of virtual content while preserving transparency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional steering elements (mirrors, gratings) are used to direct display light, then virtual content can be displayed, but out-of-band wavelengths are reflected or diffracted out, reducing see-through transparency and field of view
Solution Approach 1:
The patent uses cholesteric liquid crystal layers with spatially varying chiral pitch to create wavelength-selective reflection. By carefully controlling the chiral pitch parameter across different regions of the display, the system achieves high efficiency display of virtual content while maintaining transparency for out-of-band wavelengths. The chiral pitch is tuned to reflect only the display wavelengths (in-band) while transmitting other wavelengths (out-of-band), thus resolving the contradiction between display quality and see-through transparency.
2Productivity
If steering elements are used to direct light, then virtual content can be displayed with some efficiency, but field of view is limited due to wavelength-selective reflection
Solution Approach 1:
The patent implements spatially varying chiral pitch across different regions of the display, where each region is optimized for its specific function. The chiral pitch is locally tuned to reflect the display wavelengths in the center region while maintaining broader transmission in peripheral regions. This local optimization allows high display efficiency in the field of view where it is most needed, while preserving overall field of view by avoiding unnecessary wavelength-selective reflection in other areas.
3Reliability
If high efficiency steering is achieved for display wavelengths, then virtual content quality improves, but see-through transparency for real-world objects deteriorates
Solution Approach 1:
The patent employs cholesteric liquid crystal layers with precisely controlled chiral pitch that is spatially varying. The chiral pitch is tuned to create a narrow reflection band for display wavelengths while maintaining high transmission for out-of-band wavelengths. This parameter control ensures that virtual content is displayed with high efficiency and quality, while real-world objects remain visible through the display with minimal interference, thus resolving the contradiction between virtual display quality and real-world visibility.
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 clarity and field of view in AR/VR devices by ensuring high-quality virtual content display while maintaining clear see-through visibility, improving user experience and resource efficiency.
Implementation Method 1
A notched cholesteric liquid crystal (CLC) layer may be used in place of the broadband CLC layer described above. As shown in FIG. 1, a CLC layer may be created by applying a CLC film to a substrate of some other material. For light propagating along the helix axis, CLC exhibits a Bragg reflection band for circularly polarized light with the same handedness as the helix.
Implementation Method 2
For light propagating along the helix axis, CLC exhibits a Bragg reflection band for circularly polarized light with the same handedness as the helix.
Implementation Method 3
cholesteric liquid crystal (CLC) layers with controlled birefringence and spatially tuned chiral pitch to selectively reflect or transmit light based on polarization
Implementation Method 4
cholesteric liquid crystal (CLC) layers with controlled birefringence and spatially tuned chiral pitch
Data Source
AI summary
A wearable head-mounted device may include (i) a display screen that comprises at least one cholesteric liquid crystal (CLC) layer, wherein the CLC layer comprises a chiral layer such that incoming circular polarized light with a first handedness exhibits a narrow band reflectance around a resonant wavelength while incoming circular polarized light with an opposite handedness to the first handedness transmits through the CLC layer and (ii) a housing that houses the display screen in front of a wearer's eyes. In some embodiments, the device may also include a physical processor that transmits data to be displayed on the display screen. Various other methods, systems, and computer-readable media are also disclosed.