Mechanically Held Polymer Lenses for Photonics Device Placement Reference
Solution Overview
Problem
Existing photonics devices face issues with lens detachment due to weakened adhesion between glue and polycarbonate lenses, especially under varying temperatures and mechanical stresses, leading to reduced robustness and durability.
Innovation Solution
A photonic device design featuring a cap with retention structures that mechanically constrain lenses, including a first retention structure with a hole and a second retention structure affixed within, allowing for precise alignment and secure positioning without relying solely on adhesive strength, using a method that involves mounting an integrated circuit on a PCB, affixing the cap, and press-fitting lenses into the retention structures with optional hardening substances for additional constraint.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If glue is used to affix the lens to the cap, then the lens can be initially positioned, but the adhesion strength weakens under varying temperatures and mechanical stresses
Solution Approach 1:
The retention structure is divided into multiple components: a cap structure with outwardly extending flanges, an intermediate structure with inwardly extending flanges, and a lens positioned between them. This segmentation distributes the mechanical constraint forces across multiple contact points rather than relying on a single adhesive bond, thereby resolving the contradiction between initial adhesion and long-term reliability under stress.
Solution Approach 2:
The patent replaces the chemical adhesion mechanism (glue) with a mechanical constraint system consisting of nested retention structures with interlocking flanges. The lens is held in place through the mechanical interference fit between the outwardly extending flanges of the cap and the inwardly extending flanges of the intermediate structure, eliminating dependence on adhesive strength under temperature and stress variations.
2Reliability
If a mechanical retention structure is added, then lens security is improved, but device complexity increases
Solution Approach 1:
The retention structure merges multiple functions into a single integrated cap assembly: the cap structure itself, the retention flanges, and the positioning mechanisms are combined into one monolithic component that can be affixed to the PCB as a single unit. This merging reduces assembly steps and overall device complexity while maintaining high lens security through the nested flange structure.
Solution Approach 2:
The cap structure serves multiple functions simultaneously: it provides mechanical support for the lens, creates the retention constraint through its flanges, provides mounting attachment to the PCB, and establishes the optical alignment reference. This multi-functionality reduces the need for separate components, thereby improving lens security without proportionally increasing device complexity.
Data Source
AI summary
A photonic device includes a PCB having an integrated circuit mounted thereon, with a cap mounted to the PCB and carrying a lens positioned over the integrated circuit. The cap is formed by: an outer wall mounted to the PCB, extending upwardly from the PCB, and surrounding a portion of the integrated circuit; a first retention structure extending inwardly from the outer wall and across the integrated circuit, the first retention structure having a hole defined therein; and a second retention structure having a hole defined therein, the second retention structure being affixed within the first retention structure such that the hole in the second retention structure is axially aligned with the hole in the first retention structure. The lens is mechanically constrained within the cap between the first retention structure and the second retention structure.