PCB Recess Optical Isolator for Intrinsic Safety
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing optical isolators in field devices face challenges in meeting intrinsic safety standards in volatile environments, where a spark or high surface temperature can ignite, and require complex component separation and testing to prevent unwanted ignitions.
Innovation Solution
The use of a printed circuit board with recesses to physically separate photoemitter and photodetector components, leveraging the board material as solid insulation to reduce component count, space, and testing effort, while ensuring compliance with intrinsic safety standards by maintaining a minimum solid insulation distance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If physical barriers are used to separate components to meet intrinsic safety standards, then safety compliance is improved, but component count and board space increase
Solution Approach 1:
The patent merges the isolation barrier function with the printed circuit board structure itself. The PCB serves dual purposes: as the mechanical support structure and as the intrinsic safety barrier, eliminating the need for separate isolation components. This is achieved by integrating the barrier directly into the board design, reducing component count while maintaining safety compliance.
Solution Approach 2:
The printed circuit board is designed to perform multiple functions simultaneously: electrical connection, mechanical support, and intrinsic safety isolation. By making the PCB multi-functional, the patent eliminates dedicated isolation components while maintaining all required safety functions, thereby reducing overall device complexity.
2Reliability
If physical barriers are used to separate components to meet intrinsic safety standards, then safety compliance is improved, but board space increases
Solution Approach 1:
The isolation barrier is merged with the PCB structure, utilizing the existing board area rather than adding separate isolation components. This integration allows the barrier to occupy minimal additional space while maintaining effective separation for intrinsic safety compliance.
Solution Approach 2:
The patent utilizes the vertical dimension of the PCB by creating recesses that extend partially through the board thickness. This dimensional approach allows photoelements to be positioned at different depths, achieving effective isolation without increasing the board's planar footprint.
3Reliability
If traditional optical isolators are used, then signal isolation is achieved, but power transfer capability is limited
Solution Approach 1:
The patent extracts the photoelements from traditional enclosed optocoupler packages and mounts them directly on the PCB surface. This extraction allows for larger, more powerful photoelement components to be used, improving power transfer capability while maintaining isolation through the PCB barrier rather than through compact packaging constraints.
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 configuration allows for efficient signal communication while reducing component protection needs and testing efforts, achieving compact and cost-effective optocouplers that satisfy intrinsic safety specifications and provide reliable isolation in hazardous environments.
Implementation Method 1
A portion of the printed circuit board is interposed between the first and second photoelements
Implementation Method 2
Optical isolators can be used to transmit data across the barrier
Data Source
AI summary
An optical isolator is provided. The optical isolator includes a printed circuit board having a first surface and a second surface opposite the first surface. The printed circuit board has a recess extending only partially through the board. The first photoelement has an active surface and is mounted relative to the first surface of the printed circuit board. A second photoelement has an active surface and is mounted relative to the second surface. The second photoelement is configured to interact with the first photoelement. At least one of the first and second photoelements has its active surface disposed at least partially in the recess. A portion of the printed circuit board is interposed between the first and second photoelements.