Optical Module Lens Alignment via Molding Die Positioning Pin
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Solution Overview
Problem
Existing optical modules face misalignment issues during resin molding, leading to increased optical coupling loss between semiconductor optical devices and external fibers due to the fluid resin affecting the encapsulated lens, which is exacerbated by temperature-dependent refractive index changes in the transparent resin.
Innovation Solution
The optical module design includes a transparent sealant with vias that supports the lens using positioning pins within the molding die, ensuring precise alignment and efficient heat dissipation through metal-filled vias, thereby maintaining optical coupling efficiency across varying temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the lens is encapsulated within the transparent sealant to compensate refractive index degradation, then the optical coupling stability is improved, but the lens is easily misaligned by the fluid resin during molding which increases optical coupling loss
Solution Approach 1:
The lens is pre-positioned and fixed to the lead frame using adhesive before the molding process. This preliminary fixation ensures that the lens maintains its precise alignment with the semiconductor optical device during the subsequent resin injection, preventing misalignment caused by fluid resin pressure while still allowing the sealant to compensate for refractive index degradation
Solution Approach 2:
The lead frame serves as an intermediary structure that mechanically supports both the semiconductor optical device and the lens. By fixing the lens to the lead frame, the system creates a stable reference framework that maintains optical alignment while the transparent sealant provides environmental protection and refractive index compensation
2Reliability
If the semiconductor optical device is encapsulated with transparent resin, then the device is protected, but heat generated by the device is not efficiently dissipated
Solution Approach 1:
The patent employs a composite sealing structure combining transparent resin for optical protection with metal materials (aluminum or copper) for thermal management. The metal sealant or metal plate integrated into the sealant provides high thermal conductivity pathways to dissipate heat from the semiconductor optical device, while the transparent resin portion maintains optical coupling stability
Solution Approach 2:
The sealant structure performs multiple functions simultaneously: it provides mechanical protection for the semiconductor device, maintains optical coupling stability through refractive index compensation, and dissipates heat through high thermal conductivity materials. This multi-functional design eliminates the need for separate protective and thermal management components
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 design effectively aligns the lens with the semiconductor optical device during resin injection, reducing optical coupling loss and maintaining high optical output power while enhancing heat dissipation, thus improving the module's performance and reliability.
Implementation Method 1
heat generated by the semiconductor optical device may be efficiently dissipated
Data Source
AI summary
A method to manufacture an optical module is disclosed, wherein the optical module has an optically active device on a lead frame and a lens co-molded with the active device and the lead frame by a transparent resin as positioning the lens with respect to the lead frame. The molding die of the present invention has a positioning pin to support the lens during the molding. Because the lead frame is aligned with the molding die, the precise alignment between the active device on the lead frame and the lens is not spoiled during the molding.