Sealed Lens Block Assembly for Immersion-Cooled Optoelectronics
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Solution Overview
Problem
Optical lens assemblies in optoelectronic modules are not designed for liquid cooling, as liquid ingress affects focal lengths and optical performance, making them inoperable.
Innovation Solution
An optoelectronic device with a sealing arrangement that allows immersion in liquid coolant while maintaining optical performance, using seals and a lens block with reflective surfaces and ferrules to prevent liquid ingress, and a PCB assembly with heat transfer features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If liquid cooling is used to improve heat dissipation efficiency, then cooling performance is improved, but optical performance deteriorates due to refractive index changes in liquid
Solution Approach 1:
The device is divided into separate sealed optical chambers and cooling channels. The optical components (lenses, ferrules, PCB assembly) are enclosed in hermetically sealed chambers that prevent liquid coolant from contacting them, while the cooling channels allow liquid flow around the PCB assembly for heat dissipation. This segmentation resolves the contradiction by isolating optical paths from liquid coolant.
Solution Approach 2:
Hermetic seals (epoxy coatings, seal rings, encapsulants) act as intermediary barriers between the liquid coolant and optical components. These seals prevent direct contact between the liquid and optical elements, maintaining the air environment necessary for proper optical function while allowing the device to be immersed in liquid coolant for cooling.
2Reliability
If optical paths are exposed to air for effective optical coupling, then optical performance is maintained, but heat dissipation efficiency deteriorates compared to liquid cooling
Solution Approach 1:
The device structure separates optical components from cooling channels, allowing optical elements to remain in air-filled sealed chambers for effective coupling while the surrounding PCB assembly and housing are exposed to liquid coolant for efficient heat dissipation. This spatial segmentation enables both air-coupled optics and liquid cooling to coexist.
Solution Approach 2:
Different regions of the device have different environmental requirements: optical components are maintained in air for proper optical coupling, while the PCB assembly and housing are exposed to liquid coolant for heat dissipation. The hermetic seals create localized air environments around optical elements while allowing liquid contact in other regions, applying local quality to resolve the contradiction.
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
Enables efficient liquid cooling without compromising optical performance by isolating optical paths from liquid coolant, allowing effective heat dissipation and maintaining optical functionality.
Implementation Method 1
A first seal seals the lens block mounted to the PCB assembly and separates the plenum from the liquid coolant. A second seal seals the reflective surface in the opening of the lens block from the liquid coolant, and a third seal seals the ferrule to the lens block from the liquid coolant. The seals can comprise an epoxy.
Implementation Method 2
The lens block defines an opening forming a reflective surface
Implementation Method 3
An optoelectronic device disclosed herein is used for immersion in a liquid coolant... allowing effective heat dissipation
Data Source
AI summary
An optoelectronic device for immersion in a liquid coolant includes a printed circuit board assembly (PCBA) having opposing sides and having an optoelectronic component coupled on one side. A lens block mounted to the side of the PCBA encloses a plenum over the optoelectronic component. An opening defined in the lens block forms a reflective surface. The lens block has a first lens facing the optoelectronic component and opposing the reflective surface. The lens block also has a second lens facing a ferrule, which connects to optical fibers and couples to the lens block. A first seal seals the lens block mounted to the PCBA and separates the plenum from the liquid coolant. An insert is disposed in the opening to protect the reflective surface, and a second seal seals the opening and the insert in the lens block. A third seal seals the ferrule to the lens block.