Waveguide Cell Material Deposition for Precise Grating Uniformity
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Solution Overview
Problem
Existing waveguide manufacturing processes face challenges in achieving precise control over grating characteristics and uniformity of optical recording material layers, particularly in constructing waveguide cells with varying optical properties for applications like augmented reality displays and sensors.
Innovation Solution
A method involving deposition of optical recording material using inkjet printing and laminating techniques, with specific mixtures of beads and liquid crystals to achieve predefined grating characteristics, such as refractive index modulation and birefringence, through a workcell cluster system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional deposition methods are used to manufacture waveguide cells, then the manufacturing process is simpler, but the precision of grating characteristics (refractive index modulation, birefringence, layer thickness) is insufficient
Solution Approach 1:
The deposition system is divided into multiple independent deposition heads, each capable of depositing specific materials (e.g., liquid crystal mixture, polymer matrix) with controlled parameters. This segmentation allows precise control over grating characteristics while maintaining modular system architecture that manages complexity.
Solution Approach 2:
Different regions of the waveguide cell receive differently formulated optical recording materials with specific bead sizes and compositions tailored to local grating requirements. This enables spatially varying diffraction efficiencies and precise local control of refractive index modulation and birefringence without requiring complete system redesign.
2Manufacturing precision
If uniform optical recording material is deposited across the entire substrate, then the deposition process is simpler, but the spatial uniformity of diffraction efficiency cannot be optimized
Solution Approach 1:
The patent deposits optical recording materials with spatially varying formulations, including different bead sizes and compositions in different regions of the substrate. This enables optimization of diffraction efficiency uniformity across the waveguide cell by tailoring material properties to local optical requirements, while the automated deposition system manages the complexity of multi-region processing.
Solution Approach 2:
The deposition process varies material parameters (bead size, composition, concentration) across different regions of the substrate to achieve uniform diffraction efficiency. By changing material parameters rather than process parameters, the system achieves precise spatial control while maintaining relatively simple deposition mechanics.
3Productivity
If multiple material formulations are deposited in a predetermined pattern, then the diffraction efficiency can be optimized, but the deposition time and process complexity increase
Solution Approach 1:
Multiple deposition heads operate simultaneously or in rapid sequence, each responsible for depositing specific material formulations in predetermined patterns. This parallelization reduces total deposition time while achieving the complex multi-material patterning required for optimized diffraction efficiency.
Solution Approach 2:
The optical recording materials are pre-formulated with specific bead sizes and compositions before deposition. This preliminary preparation allows the deposition process to focus on precise spatial placement rather than material synthesis, reducing deposition time while maintaining the ability to create complex multi-material patterns for high diffraction efficiency.
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
Enables the production of waveguide cells with spatially varying diffraction efficiency and uniform layer thickness, enhancing the performance of waveguide devices in applications like AR displays and sensors.
Implementation Method 1
The method involves using a deposition process with multiple deposition heads to deposit layers of optical recording material with specific formulations and bead sizes, allowing for precise control of grating characteristics. This includes using inkjet print heads to deposit materials with varying compositions and bead sizes
Implementation Method 2
Holographic optical elements, such as volume phase gratings, can be recorded in such a liquid mixture by illuminating the material with two mutually coherent laser beams. During the recording process, the monomers polymerize and the mixture undergoes a photopolymerization-induced phase separation, creating regions densely populated by liquid crystal micro-droplets, interspersed with regions of clear polymer
Implementation Method 3
During the recording process, the monomers polymerize and the mixture undergoes a photopolymerization-induced phase separation, creating regions densely populated by liquid crystal micro-droplets, interspersed with regions of clear polymer. The alternating liquid crystal-rich and liquid crystal-depleted regions form the fringe planes of the grating
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 (TIR)
Implementation Method 5
planar waveguides can be designed to utilize diffraction gratings to diffract and couple incident light into the waveguide structure
Data Source
AI summary
Systems for the manufacturing of waveguide cells in accordance with various embodiments can be configured and implemented in many different ways. In many embodiments, various deposition mechanisms are used to deposit layer(s) of optical recording material onto a transparent substrate. A second transparent substrate can be provided, and the three layers can be laminated to form a waveguide cell. Suitable optical recording material can vary widely depending on the given application. In some embodiments, the optical recording material deposited has a similar composition throughout the layer. In a number of embodiments, the optical recording material spatially varies in composition, allowing for the formation of optical elements with varying characteristics. Regardless of the composition of the optical recording material, any method of placing or depositing the optical recording material onto a substrate can be utilized.