Multi-Waveguide Light Field Display Using Composite Grating Layers
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Solution Overview
Problem
Existing waveguide displays require complex and costly processes, such as dry etching, to form diffraction gratings in high-index substrates like glass or sapphire, which limits manufacturing efficiency and environmental stability.
Innovation Solution
A multi-waveguide optical structure is developed, where each waveguide has a patterned layer with a diffraction grating and a substrate with a high index of refraction, eliminating the need for etching by using a composite structure with a patterned layer and a substrate, and enhancing environmental stability through anti-reflective layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If dry etching is used to form diffraction gratings in high-index substrates, then diffraction efficiency is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The waveguide structure is segmented into multiple functional layers: a substrate layer, a patterned layer containing the diffraction grating, and an adhesive layer. This segmentation allows the diffraction grating to be formed in a separate patterned layer rather than requiring complex etching of the entire substrate, thereby reducing manufacturing complexity while maintaining diffraction efficiency.
Solution Approach 2:
The invention uses a composite structure combining a substrate with a patterned layer deposited on it. The patterned layer contains the diffraction grating structure and has different material properties than the substrate. This composite approach enables formation of diffraction gratings through deposition and patterning processes rather than substrate etching, simplifying manufacturing while achieving high diffraction efficiency.
2Reliability
If etching processes are used to create diffraction gratings, then optical performance is improved, but manufacturing cost and time increase
Solution Approach 1:
The diffraction grating pattern is pre-formed in a separate patterned layer through deposition and patterning processes before being integrated with the substrate. This preliminary action avoids the need for time-consuming etching processes on the final waveguide structure, thereby improving manufacturing efficiency while maintaining optical performance.
Solution Approach 2:
The diffraction grating pattern is created as a separate patterned layer that copies the required optical function without requiring direct modification of the substrate. This copying approach allows for more efficient manufacturing processes while achieving the same optical performance as etched gratings.
3Stability of the object's composition
If adhesive layers are added to bond patterned layer to substrate, then structural stability is improved, but optical path complexity increases
Solution Approach 1:
The adhesive layer is designed as a thin, simple bonding layer whose primary function is structural attachment. While it adds a layer to the structure, the adhesive layer is optically transparent and does not significantly complicate the optical path, providing structural stability with minimal optical impact.
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 solution simplifies the manufacturing process, reduces costs, and enhances the environmental stability and optical efficiency of waveguide displays, while maintaining high diffraction efficiency and a wide field of view.
Implementation Method 1
Diffraction gratings are optical components with periodic structures that can split and diffract light into several beams travelling into different directions. The directions of these beams depend on the spacing of the grating and the wavelength of the light.
Implementation Method 2
the first adhesive layer providing adhesion between the patterned layer and the substrate
Implementation Method 3
Each waveguide further comprises an anti-reflective layer positioned between the substrate and the second adhesive layer
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A multi-waveguide optical structure, including multiple waveguides stacked to intercept light passing sequentially through each waveguide, each waveguide associated with a differing color and a differing depth of plane, each waveguide including: a first adhesive layer, a substrate having a first index of refraction, and a patterned layer positioned such that the first adhesive layer is between the patterned layer and the substrate, the first adhesive layer providing adhesion between the patterned layer and the substrate, the patterned layer having a second index of refraction less than the first index of refraction, the patterned layer defining a diffraction grating, wherein a field of view associated with the waveguide is based on the first and the second indices of refraction.