Compound Light-Guide Optical Element Assembly With Spacer-Plate Alignment
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Solution Overview
Problem
Existing methods for fabricating compound light-guide optical elements (LOEs) face challenges in precise alignment during bonding, leading to misalignment issues and the need for separate cover plates, which complicates the manufacturing process.
Innovation Solution
A method involving the formation of a bonded stack of LOE precursors and transparent spacer plates, followed by alignment and bonding with an optical block, then slicing to create compound LOEs, eliminating the need for separate cover plates and improving alignment precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If existing bonding methods are used for fabricating compound LOEs, then alignment can be achieved, but misalignment issues occur and separate cover plates are required, complicating the manufacturing process
Solution Approach 1:
The patent combines the alignment function and structural support function into a single integrated component. The transparent spacer plate is designed with built-in alignment features (alignment marks or geometric features) that directly interface with both the LOE precursor and the cover plate, eliminating the need for separate alignment mechanisms and reducing the number of discrete components required in the assembly process
Solution Approach 2:
The transparent spacer plate serves as an intermediary component between the LOE precursor and the cover plate. It provides a stable bonding interface with integrated alignment features that facilitate precise alignment during the bonding process, while also maintaining the optical path and providing structural support, thereby simplifying the overall manufacturing process
2Reliability
If separate cover plates are used to compensate for misalignment, then alignment issues can be addressed, but the manufacturing process becomes more complex
Solution Approach 1:
The alignment function previously requiring separate cover plates is merged into the transparent spacer plate itself. The spacer plate incorporates alignment features (such as alignment marks or geometric reference features) that enable precise alignment during bonding, eliminating the need for additional cover plates while maintaining or improving alignment reliability
3Productivity
If traditional fabrication methods are used, then compound LOEs can be produced, but manufacturing efficiency is reduced due to misalignment and process complexity
Solution Approach 1:
The transparent spacer plate is pre-fabricated with integrated alignment features before the bonding process. These alignment features (alignment marks, geometric reference features) are built into the spacer plate structure in advance, enabling rapid and accurate alignment during assembly without requiring complex adjustment procedures or additional components, thereby significantly improving manufacturing 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
This method enhances manufacturing efficiency by reducing misalignment and simplifies the process, allowing for the production of compound LOEs with improved structural integrity and optical performance.
Implementation Method 1
supporting propagation of light carrying a collimated image by internal reflection at major surfaces
Implementation Method 2
providing a bonded stack of a plurality of LOE precursors and a plurality of transparent spacer plates
Data Source
AI summary
A method of fabricating a compound light-guide optical element (LOE) is provided. A bonded stack of a plurality of LOE precursors and a plurality of transparent spacer plates alternating therebetween is bonded to a first optical block having a plurality of mutually parallel obliquely angled internal surfaces. The block is joined to the stack such that first plurality of partially reflective internal surfaces of the block is non-parallel to the internal surfaces of the LOE precursor. After bonding, a second optical is thereby formed. At least one compound LOE is sliced-out of the second optical block by cutting the second block through at least two consecutive spacer plates having a LOE precursor sandwiched therebetween.