Polymer Reflective Waveguide Overmolding Adhesive-Free Bonding
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Solution Overview
Problem
Current manufacturing processes for glass-based reflective waveguides for augmented reality (AR) displays are complex and inefficient, leading to material waste and high production costs. Additionally, the use of index-matched adhesive layers in polymer waveguide fabrication is stringent and complicates the bonding process.
Innovation Solution
The technique of overmolding or overcasting is used to fuse portions of the reflective waveguide without an adhesive layer, simplifying the fabrication process and reducing material waste. This method involves selecting materials with closely matched refractive indices and thermal properties to ensure strong adhesion and maintain the structural integrity of the waveguide.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If index-matched adhesive layers are used in polymer waveguide fabrication, then bonding between waveguide portions is achieved, but the manufacturing process becomes complex and stringent
Solution Approach 1:
The patent removes the adhesive layer from the waveguide fabrication process entirely. Instead of bonding separate waveguide portions with index-matched adhesives, the invention integrates the entire waveguide as a single molded polymer component, eliminating the adhesive layer and its associated alignment and bonding complexity while maintaining structural integrity
Solution Approach 2:
The invention merges multiple waveguide portions that would traditionally be bonded with adhesive into a single integrated polymer component. This consolidation eliminates the interface between separate parts and the need for adhesive layers, simplifying the fabrication process while maintaining optical performance
2Strength
If traditional glass-based waveguide manufacturing is used, then structural integrity is achieved, but material waste increases and production costs rise
Solution Approach 1:
The patent changes the material parameter from traditional glass to polymer, enabling additive manufacturing processes that build waveguides layer by layer without material removal. This parameter change maintains sufficient structural integrity for optical applications while dramatically reducing material waste compared to subtractive glass processing
Solution Approach 2:
The invention utilizes the phase transition properties of polymer materials during additive manufacturing, where material is deposited in a molten or soft state and then solidifies to form the waveguide structure. This approach allows for precise material placement with minimal waste, contrasting with glass processing that requires high-energy melting and subtractive shaping
3Manufacturing precision
If multiple process steps are used for waveguide fabrication, then manufacturing precision is maintained, but productivity decreases
Solution Approach 1:
The patent combines multiple fabrication steps into a single additive manufacturing process. The waveguide structure, including complex internal geometries and optical features, is built in one continuous printing process rather than through sequential machining, assembly, and coating steps, thereby maintaining precision while大幅提升 productivity
Solution Approach 2:
The invention performs preliminary design and simulation of the waveguide structure before manufacturing, allowing the additive process to directly create the final precision geometry without intermediate machining or adjustment steps. This preliminary digital modeling ensures manufacturing precision is achieved through the printing process itself rather than through multiple corrective steps
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 approach reduces the number of process steps required for fabricating polymer-based reflective waveguides, simplifies the manufacturing process, and eliminates the need for index-matched adhesive layers, thereby improving efficiency and reducing material waste while maintaining high display quality.
Implementation Method 1
the second material is overmolded or overcast to the first material to form a second portion of the reflective waveguide without an adhesive layer
Implementation Method 2
the second material is overcast to the first material to form a second portion of the reflective waveguide without an adhesive layer
Implementation Method 3
the light beams are 'guided' through the substrate, typically by multiple instances of total internal reflection, to then be directed out of the waveguide
Data Source
AI summary
Overmolding or overcasting one portion of a reflective waveguide to another portion achieves bonding of components of the reflective waveguide without the need for an index-matched adhesive or an alignment platform for bonding. In embodiments in which one portion is overmolded to the other, the materials used to form the portions are selected such that the material used to form a first portion has a glass transition temperature (Tg) that is higher than the Tg of the material used to form a second portion. In embodiments in which one portion is overcasted to the other, the materials used to form the first portion and the second portion are thermosetting resins and are selected such that both materials have solubility parameters that approximately match each other.