AR Goggle Polarization Optics for Higher Light Utilization and Contrast
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Solution Overview
Problem
Conventional augmented reality display systems suffer from low light energy utilization and interference from external environment light, resulting in reduced image brightness and contrast.
Innovation Solution
The system employs a circular polarization optical reflector, a phase delay sheet, and a linear polarization absorption component to enhance light energy utilization and contrast by converting and filtering light polarization directions, using a cholesterol liquid crystal layer to adjust reflectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional optical splitter and curved reflector with reflective-and-transmissive film layer are used, then the system can display a to-be-displayed image, but the light energy utilization rate is low (only 12.5% of energy reaches the human eye)
Solution Approach 1:
The patent changes the polarization state parameter of light by introducing a quarter-wave plate that converts linearly polarized light to circularly polarized light. This allows the optical reflector to reflect 100% of the light energy (since circularly polarized light is not filtered by the linear polarization filter), thereby achieving a light energy utilization rate of 50% or higher, resolving the energy loss problem in conventional AR displays
Solution Approach 2:
The quarter-wave plate acts as an intermediary component between the linear polarization optical splitter and the circular polarization optical reflector. It converts the linearly polarized light from the image display into circularly polarized light, enabling efficient reflection at the optical reflector while maintaining compatibility with the linear polarization filtering mechanism, thus solving the energy utilization contradiction
2Object-affected harmful factors
If a conventional optical system with multiple reflections is used, then the system can form a to-be-displayed image, but external environment light interferes with the display image
Solution Approach 1:
The patent converts the harmful effect of external environment light interference into a beneficial feature by utilizing polarization characteristics. The linear polarization absorption component absorbs horizontally polarized environmental light while the circular polarization optical reflector reflects circularly polarized display light. This transforms the interference problem into an advantage, as the system can selectively filter environmental light based on its polarization state while maintaining display image brightness
Solution Approach 2:
The patent applies different polarization filtering properties to different components: the linear polarization absorption component selectively absorbs horizontally polarized light, while the circular polarization optical reflector selectively reflects circularly polarized light. This local differentiation of polarization handling allows the system to reject environmental interference while preserving display quality
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 system achieves a light energy utilization rate of 55% to 100% and increases image contrast, providing brighter and higher quality viewing experiences with reduced power consumption.
Implementation Method 1
The linear polarization optical splitter is configured to reflect light with a first linear polarization direction and allow light with a second linear polarization direction to pass therethrough
Implementation Method 2
The phase delay sheet is configured to convert the first image beam into a second image beam with a first circular polarization direction
Implementation Method 3
The circular polarization optical reflector is configured to reflect the second image beam into a third image beam with a second circular polarization direction and reflect the third image beam back to the phase delay sheet
Implementation Method 4
The linear polarization absorption component is configured to absorb light with the first linear polarization direction and allow light with the second linear polarization direction to pass therethrough
Data Source
AI summary
An augmented reality display system includes an image display, a linear polarization optical splitter, a phase delay sheet, a circular polarization optical reflector and a linear polarization absorption component. The image display provides a first beam with a first linear polarization direction, which is reflected by the linear polarization optical splitter to the phase delay sheet. The phase delay sheet converts the first beam into a second beam with a first circular polarization direction and transmits it to the circular polarization optical reflector. The circular polarization optical reflector converts the second beam into a third beam with a second round polarization direction and reflects it to the phase delay sheet. The phase delay sheet converts the third beam into a fourth beam with a second linear polarization direction, which passes through the linear polarization optical splitter and the linear polarization absorption component to form an image.