Alignment Spacer Adhesive Retention for Optoelectronic Modules
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Solution Overview
Problem
Existing optoelectronic modules face challenges in achieving precise alignment between optical assemblies and active optoelectronic components while maintaining a small footprint, mechanical stability, and light-tight seal, as excessive adhesive deposition can lead to adhesive migration, mechanical integrity issues, and stray light concerns.
Innovation Solution
The use of alignment spacers with extensions and chamfered surfaces or grooves limits adhesive migration, allowing for a small bond line and enhanced mechanical stability, and the incorporation of non-transparent adhesives forms a light-tight seal around the active optoelectronic components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If excessive adhesive is deposited onto the substrate to ensure light-tight seal and mechanical integrity, then the bond line strength and light-tightness are improved, but the module footprint increases due to adhesive migration
Solution Approach 1:
The patent extracts the adhesive migration problem by introducing a dedicated adhesive retention feature (such as a groove or chamfered surface) on the spacer. This feature captures and confines the excessive adhesive, preventing it from migrating onto the active optoelectronic component. The harmful excess adhesive is thus 'taken out' from the migration path and contained in a specific location, resolving the contradiction between using enough adhesive for sealing and preventing footprint increase from migration.
2Area of stationary object
If the module footprint is reduced to accommodate compact design, then the device size is minimized, but adhesive may migrate onto the active optoelectronic component causing damage
Solution Approach 1:
The patent introduces an intermediary structure (adhesive retention feature on the spacer) that mediates between the adhesive and the active optoelectronic component. This intermediary captures the excessive adhesive before it can reach and damage the component, allowing the module to maintain a compact footprint while still protecting the sensitive component from adhesive migration damage.
3Area of stationary object
If adhesive amount is reduced to minimize footprint, then the module size decreases, but adhesive-free gaps form compromising mechanical integrity and light-tightness
Solution Approach 1:
The patent extracts the excess adhesive from the bonding process and directs it into a retention feature (groove or chamfered surface) on the spacer. This allows the bond line to maintain sufficient adhesive for mechanical strength and light-tightness without requiring excessive adhesive that would increase the footprint. The retention feature effectively removes the harmful excess while preserving the necessary adhesive amount.
4Measurement precision
If precise alignment is achieved through active alignment process, then the optical performance is optimized, but the alignment tolerance becomes very tight
Solution Approach 1:
The patent employs self-aligning features such as mechanical interlocking elements, registration marks, or geometry-based alignment mechanisms that enable the optical assembly and substrate to automatically align during assembly. This self-service alignment reduces dependence on tight manufacturing tolerances and active alignment processes, while still achieving the necessary optical precision, thereby resolving the contradiction between alignment precision and manufacturing tolerance.
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 solution enables precise alignment, reduces the module footprint, maintains mechanical stability, and ensures a light-tight seal, preventing adhesive migration and stray light issues, thereby improving the performance and reliability of optoelectronic modules.
Implementation Method 1
fixing an optical assembly to a spacer (e.g., by adhesive)
Implementation Method 2
as the previously deposited adhesive is in an uncured state
Implementation Method 3
light reflecting from a test target can be directed through an optical assembly
Implementation Method 4
directed through an optical assembly
Implementation Method 5
The adhesive (e.g., along the bond line) is then at least partially cured thereby fixing the optical assembly and active optoelectronic component in place
Data Source
AI summary
Optoelectronic modules, such as proximity sensors, two-dimensional and three-dimensional cameras, structured- or encoded-light emitters, and projectors include optical assemblies and active optoelectronic components that are light sensitive or emit light. The optical assemblies are aligned to the active optoelectronic components via alignment spacers and adhesive. The alignment spacers include surfaces operable to limit the lateral migration of adhesive thereby preventing the contamination of the active optoelectronic components with adhesive. In some instances, small optoelectronic module footprints can be maintained without compromising the integrity of the adhesive.