Optical Component Passive Alignment via Machine Vision
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Solution Overview
Problem
Current passive alignment methods for optical components in transceivers lack the precision of active alignment methods, resulting in reduced accuracy and higher margins of error, particularly due to the difficulty in accurately determining the optical axis position from blurred peripheral edges in captured images.
Innovation Solution
A machine vision system is employed to position and align an optical subassembly relative to an electrical subassembly, using alignment members on the optical subassembly that are easily detectable, such as rectangular or concentric blocks, to improve the accuracy of optical axis determination through image processing and positioning adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If passive alignment is used to reduce cost and improve yield, then manufacturing cost is reduced and productivity is improved, but alignment precision deteriorates
Solution Approach 1:
The patent introduces alignment members as intermediary reference structures that are formed on the optical subassembly during molding. These members serve as mediators between the optical component and the positioning system, enabling the machine vision system to accurately determine the optical axis position without requiring active photonic devices. This resolves the contradiction by providing a cost-effective passive alignment method that achieves precision comparable to active alignment.
Solution Approach 2:
The alignment members are formed as copies or replicas of the optical component's structure from the same mold, creating reference features that accurately represent the optical axis position. This copying approach allows the machine vision system to determine alignment based on the alignment members' positions, which directly correspond to the optical component's optical axis, thereby maintaining precision while using passive methods.
2Device complexity
If alignment members are formed from the same material as the molded lens, then manufacturing complexity is reduced, but detection difficulty increases due to similar optical properties
Solution Approach 1:
The patent applies local quality by creating alignment members with distinct geometric characteristics (such as rectangular blocks or concentric circles) at specific locations on the optical subassembly. While the material composition remains the same as the optical component, the local geometric quality differs significantly, making these specific regions easily detectable by the machine vision system through shape recognition rather than material property detection.
Solution Approach 2:
The patent employs geometric 'color' or contrast changes rather than material composition changes. The alignment members have distinct shapes (rectangular blocks, concentric circles) that create visual contrast and geometric signatures detectable by the machine vision system. This geometric differentiation allows easy detection despite the members being made from the same material as the optical component, resolving the detection difficulty while maintaining manufacturing simplicity.
Data Source
AI summary
Various embodiments of machine vision systems, methods, and devices are disclosed for providing passive alignment of an optical component to an electrical device. One embodiment is a method for passively aligning an optical subassembly to an electrical subassembly. One such method comprises: a machine vision system positioning an optical subassembly relative to an electrical subassembly; the machine vision system capturing an image of the optical subassembly; the machine vision system processing the image to identify an alignment member formed on the optical subassembly; and the machine vision system determining a first position of the optical axis of the optical subassembly based on a second position of the alignment member.