Optical Waveguide Fabrication Using Single-Beam Holographic Mastering
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Solution Overview
Problem
Existing waveguide fabrication methods face challenges in efficiently recording holographic gratings, particularly in high-volume manufacturing, due to alignment complexities and thermal/vibrational issues with multiple energy beams, limiting the production of advanced display and sensor applications like AR/VR and HUDs.
Innovation Solution
A single energy beam mastering system is employed to fabricate holographic waveguides, utilizing features like chirp, dual chirped gratings, zero-order grating, and alignment reference gratings, enabling rapid alignment and reducing wavefront errors, suitable for high-volume manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple energy beams are used for recording holographic gratings, then manufacturing precision can be improved, but device complexity and alignment difficulty increase
Solution Approach 1:
The patent extracts and eliminates the need for multiple energy beams by using a single beam system with a master grating. The master grating is used to generate the reference beam and object beam from a single source, simplifying the mastering system while maintaining the ability to record high-quality holographic gratings.
Solution Approach 2:
The master grating acts as an intermediary element that converts a single energy beam into the necessary beam configurations for holographic recording. It mediates between the simple single-beam input and the complex multi-beam interference pattern required for grating formation, enabling precise control without multiple independent beams.
2Manufacturing precision
If multiple energy beams are used for recording, then manufacturing precision improves, but alignment time and operational difficulty increase
Solution Approach 1:
The patent removes the alignment complexity associated with multiple independent energy beams by using a single beam system. The master grating automatically establishes the geometric relationships between beams, eliminating manual alignment operations while preserving recording precision.
Solution Approach 2:
The master grating performs self-alignment by inherently defining the beam geometry through its physical structure. The system serves itself by using the master grating's fixed geometry to automatically establish correct beam paths and interference patterns without requiring external alignment adjustments.
3Manufacturing precision
If multiple energy beams are used, then holographic grating quality improves, but thermal and vibrational stability requirements increase
Solution Approach 1:
The patent eliminates the thermal and vibrational instability problems associated with multiple independent energy beams by using a single beam system. Since all beams originate from one source, thermal drift and vibrations affect all beams equally, maintaining their relative geometric relationships and interference patterns.
Solution Approach 2:
The patent merges multiple beam functions into a single energy beam source. By deriving all necessary beams from one common source through the master grating, the system combines the thermal and vibrational characteristics of a single source, reducing the cumulative stability issues that would arise from multiple independent sources.
4Device complexity
If single energy beam is used, then device complexity and alignment difficulty reduce, but manufacturing precision may be limited
Solution Approach 1:
The master grating serves as an intermediary that enables a single energy beam to achieve the functional equivalence of multiple beams. It transforms the simple single-beam input into the complex interference pattern required for high-precision holographic grating recording, bridging the gap between simplicity and precision.
Solution Approach 2:
The master grating segments the single energy beam into multiple functional beam paths through diffraction and reflection. This segmentation allows one beam to perform the roles of multiple beams, creating the necessary interference patterns for precise grating recording while maintaining system simplicity.
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 single beam process simplifies alignment and reduces errors, facilitating high-volume production of waveguides for advanced displays and sensors, such as AR/VR and HUDs, with improved efficiency and reduced complexity.
Implementation Method 1
upon interaction with the master grating, a portion of the at least one recording beam is diffracted towards the waveguide cell
Implementation Method 2
During the recording process, the monomers polymerize and the mixture undergoes a photopolymerization-induced phase separation
Implementation Method 3
the mixture undergoes a photopolymerization-induced phase separation, creating regions densely populated by liquid crystal micro-droplets
Implementation Method 4
planar waveguides can be designed to utilize diffraction gratings to diffract and couple incident light into the waveguide structure such that the in-coupled light can proceed to travel within the planar structure via total internal reflection
Data Source
AI summary
Mastering systems and methods of fabricating waveguides and waveguide devices using such mastering systems are described. Mastering systems for fabricating holographic waveguides can include using a master to control the application of energy (e.g. a laser, light, or magnetic beam) onto a liquid crystal substrate to fabricate a holographic waveguide into the liquid crystal substrate. Mastering systems for fabricating holographic waveguides in accordance with embodiments of the invention can include a variety of features. These features include, but are not limited to: chirp for single input beam copy (near i.e. hybrid contact copy), dual chirped gratings (for input and output), zero order grating for transmittance control, alignment reference gratings, 3:1 construction, position adjustment tooling to enable rapid alignment, optimization of lens and window thickness for multiple RKVs simultaneously, and avoidance of other orders and crossover of the diffraction beam.