Augmented Reality Waveguide Polarization Conversion
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Solution Overview
Problem
Current augmented reality devices using geometric optical waveguides suffer from low light throughput efficiency due to polarization state limitations, resulting in reduced display brightness and a complex structure, which hinders the integration of high-brightness augmented reality displays.
Innovation Solution
An augmented reality device comprising a micro display emitting light in multiple polarization states, with an augmented reality element that converts light portions between polarization states, allowing for improved light utilization and coupling into an optical waveguide, thereby enhancing light throughput efficiency and simplifying the structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If geometric optical waveguide is used for augmented reality display, then the device structure is compact and wearable, but light throughput efficiency is low due to polarization state limitations
Solution Approach 1:
The patent changes the polarization state parameter of light by introducing a polarization converter that transforms linearly polarized light into circularly polarized light. This parameter change enables the light to satisfy total internal reflection conditions in the waveguide, thereby improving light throughput efficiency without requiring complex projection systems
Solution Approach 2:
The patent introduces a polarization converter as an intermediary component between the light source and the waveguide. This intermediary device converts the polarization state of light, enabling efficient coupling into the waveguide and improving overall light throughput while maintaining a compact structure
2Ease of operation
If polarization beam splitter is used to switch light paths, then light can be directed to different paths, but device structure becomes complex with multiple optical components
Solution Approach 1:
The patent extracts the polarization conversion function from the complex beam splitter system and implements it through a dedicated polarization converter component. This simplifies the overall optical path by separating the polarization control function from the light guiding function, reducing the number of required optical components
Solution Approach 2:
Instead of using beam splitters to actively direct light paths through complex switching mechanisms, the patent inverts the approach by using total internal reflection in the waveguide to naturally guide light, with the polarization converter passively preparing the light state. This eliminates the need for complex active switching components
3Illumination intensity
If multiple optical components are used for light coupling and path switching, then light can be effectively managed, but display brightness is reduced due to cumulative optical losses
Solution Approach 1:
By changing the polarization state parameter of light to circular polarization, the system enables total internal reflection in the waveguide with minimal loss. This parameter change eliminates the need for multiple beam splitter components, thereby reducing cumulative optical losses and improving display brightness
Solution Approach 2:
The patent implements continuous light guidance through the waveguide using total internal reflection, eliminating the need for discrete beam splitting and recombining operations. This continuous action reduces the number of optical interfaces and minimizes cumulative optical losses, thereby improving display brightness
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 improves light throughput efficiency, increasing display brightness and simplifying the device structure, while also enabling the detection of user fatigue and providing prompt information for enhanced safety without the need for a complex projection system.
Implementation Method 1
an augmented reality element configured to convert a first light portion in a first polarization state into a second polarization state, to convert a second light portion in a second polarization state into the first polarization state
Implementation Method 2
an optical waveguide element configured to receive the first light portion in the second polarization state and the second light portion in the first polarization state, and to transmit the first light portion and the second light portion
Data Source
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AI summary
An augmented reality device, an augmented reality system and an information prompt method thereof. The augmented reality device includes a micro display (11), an augmented reality element (12) and an optical waveguide element (13). The micro display (11) is configured to emit light carrying display content, the light includes a first light portion (DP1) in a first polarization state and a second light portion (DS2) in a second polarization state; the augmented reality element (12) is configured to allow the first light portion (DP1) to convert from the first polarization state into the second polarization state, to allow the second light portion to convert from the second polarization state into the first polarization state, and to couple the first light portion (DS1) in the second polarization state and the second light portion (DP2) in the first polarization state to the optical waveguide element (13); the first polarization state is perpendicular to the second polarization state.