Stacked Optical Waveguide Assembly for 2D Pupil Expansion
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Solution Overview
Problem
Existing two-dimensional array optical waveguides in near-eye display devices suffer from poor user experience due to the arrangement of primary and secondary pupil expansion structures on the same waveguide substrate, limiting the utilization of spatial regions and affecting product design.
Innovation Solution
The optical waveguide assembly includes a first and second waveguide plate with separate pupil expansion structures and an optical path turning element, allowing light to be expanded in two directions and coupled out efficiently, optimizing the structural design and improving user experience.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If primary and secondary pupil expansion structures are arranged on the same waveguide substrate, then the device volume is reduced, but the spatial region utilization is poor and user experience deteriorates
Solution Approach 1:
The patent divides the pupil expansion function into two separate structures (first and second pupil expansion structures) located on different waveguide substrates. This segmentation allows each structure to be optimized independently and enables better spatial distribution of the optical paths, resolving the contradiction between compact volume and user experience by separating the functions that were previously constrained to a single substrate.
Solution Approach 2:
The patent introduces a vertical stacking dimension by placing the first and second waveguide substrates at different heights (first height and second height respectively). This dimensional transition allows the optical paths to be separated in the vertical direction while maintaining a compact horizontal footprint, thus achieving both small device volume and improved spatial region utilization for better user experience.
2Device complexity
If primary and secondary pupil expansion structures are arranged on the same waveguide substrate, then the structure is simplified, but the spatial region utilization rate decreases
Solution Approach 1:
The patent segments the pupil expansion structures into two independent components on separate waveguide substrates. This segmentation enables each structure to utilize its designated spatial region more effectively, improving the overall spatial region utilization rate while the modular nature of the segmentation keeps the structural complexity manageable.
Solution Approach 2:
By transitioning to a multi-layer vertical arrangement with waveguide substrates at different heights, the patent enables more efficient use of three-dimensional space. This dimensional change allows the optical paths to be distributed in the vertical direction, significantly improving spatial region utilization without substantially increasing structural complexity.
3Manufacturing precision
If the upper structure performs pupil expansion and emits light to the lower structure, then the two-dimensional array expansion is achieved, but the light is coupled out only from the lower region of the lens affecting product design
Solution Approach 1:
The patent segments the light coupling function by providing separate coupling regions on different waveguide substrates. The first waveguide substrate has a first coupling region and the second waveguide substrate has a second coupling region, allowing light to be coupled out from multiple spatial locations. This segmentation enables versatile product design while maintaining precise imaging through each expanded light path.
Solution Approach 2:
The patent utilizes vertical dimensionality by positioning coupling regions at different heights (first height and second height). This allows the system to achieve two-dimensional array expansion while coupling light out from multiple vertical positions, not just the lower region. This dimensional approach enhances both imaging quality and product design flexibility by enabling various optical path configurations.
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 utilization of spatial regions, improves imaging quality, and optimizes the structural design of near-eye display devices by allowing two-dimensional light expansion and efficient coupling of light into the human eye.
Implementation Method 1
A first pupil expansion structure is disposed in the first waveguide plate. The first pupil expansion structure expands light in the first waveguide plate in a first direction.
Implementation Method 2
A first pupil expansion structure is disposed in the first waveguide plate. The first pupil expansion structure expands light in the first waveguide plate in a first direction.
Implementation Method 3
A second pupil expansion structure is disposed in the second waveguide plate. The second pupil expansion structure expands light in the second waveguide plate in a second direction.
Implementation Method 4
A second pupil expansion structure is disposed in the second waveguide plate. The second pupil expansion structure expands light in the second waveguide plate in a second direction.
Implementation Method 5
The optical path turning element includes multiple reflectors. After passing through the plurality of reflectors, the expanded light emitted from the first pupil expansion structure is emitted to the second pupil expansion structure.
Implementation Method 6
The turning prism is provided with a first reflection surface and a second reflection surface. The expanded light emitted from the first waveguide plate is reflected by the first reflection surface and then emitted to the second reflection surface. The second reflection surface reflects the light and emits the light to the second pupil expansion structure.
Implementation Method 7
The quarter-wave plates are disposed on both one side of the first reflection surface facing the turning prism and one side of the second reflection surface facing the turning prism. The quarter-wave plates are configured to change a vibration direction of light.
Implementation Method 8
The optical path turning element is disposed on one end of the first waveguide plate and one end of the second waveguide plate. The optical path turning element is configured to receive expanded light emitted from the first pupil expansion structure and emit the expanded light to the second pupil expansion structure.
Data Source
AI summary
Disclosed are an optical waveguide assembly and a near-eye display device. The optical waveguide assembly includes a first waveguide plate, a second waveguide plate, and an optical path turning element. A first pupil expansion structure is disposed in the first waveguide plate. The first pupil expansion structure expands light in the first waveguide plate in a first direction. The second waveguide plate and the first waveguide plate are stacked. A second pupil expansion structure is disposed in the second waveguide plate. The second pupil expansion structure expands light in the second waveguide plate in a second direction. An included angle is formed between the first direction and the second direction. The optical path turning element is disposed on one end of the first waveguide plate and one end of the second waveguide plate.