PCB Optical Waveguide for Sensor Compensation
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Solution Overview
Problem
Existing opto-electronic measuring arrangements face challenges in compactness and cost-effectiveness due to the need for separate fiber optics for compensation, which are difficult to install and sensitive to mechanical loads, and require additional hardware and assembly effort.
Innovation Solution
The use of a printed circuit board (PCB) as an optical system to guide the compensation light from the compensation light source to the receiver, eliminating the need for separate fiber optics and integrating the compensation light source within the PCB, allowing for efficient and robust optical coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate fiber optics are used for compensation light transmission, then optical coupling accuracy is improved, but device complexity and assembly difficulty increase
Solution Approach 1:
The patent merges the compensation light transmission function into the PCB structure itself. The PCB serves dual purposes: as the electrical circuit board and as the optical waveguide for transmitting compensation light from the compensation LED to the photodiode. This eliminates the need for separate fiber optics and reduces hardware complexity while maintaining optical coupling accuracy through precise manufacturing of the PCB light transmission path.
Solution Approach 2:
The PCB is designed to perform multiple functions simultaneously: it provides electrical connections for all components and serves as an integrated optical waveguide for the compensation light path. This multi-functionality eliminates the need for dedicated fiber optic components, reducing both device complexity and assembly difficulty while maintaining the required optical coupling precision.
2Reliability
If separate fiber optics are used for compensation, then optical signal transmission is improved, but ease of manufacture deteriorates
Solution Approach 1:
The compensation light transmission path is merged into the PCB structure during the standard PCB manufacturing process. The light transmission channels are created as integral parts of the PCB laminate structure, allowing the entire assembly to be manufactured in one process without requiring separate fiber optic installation, thereby improving ease of manufacture while maintaining reliable optical signal transmission.
Solution Approach 2:
The PCB structure itself provides the optical waveguide function without requiring external fiber optic components. The manufacturing process creates self-contained light transmission paths within the PCB material, eliminating the need for separate assembly steps for fiber optic installation and reducing overall assembly effort while ensuring reliable optical signal transmission.
3Measurement precision
If separate fiber optics are used, then optical coupling is improved, but mechanical robustness deteriorates
Solution Approach 1:
The optical coupling path is merged into the rigid PCB structure, which provides mechanical support and protection. The PCB's inherent mechanical strength protects the light transmission path from damage, eliminating the fragility associated with separate fiber optics while maintaining precise optical coupling through the structurally stable PCB platform.
4Device complexity
If compensation light source is integrated in PCB, then device complexity is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The PCB manufacturing process itself is used to create the precise optical transmission paths. Standard PCB fabrication techniques, including controlled copper trace routing and dielectric layer positioning, provide the necessary precision for optical coupling without requiring additional manufacturing steps or specialized equipment, thereby reducing device complexity while managing manufacturing precision requirements through existing capabilities.
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 approach results in a more compact, cost-effective, and tolerant opto-electronic measuring arrangement that maintains accurate signal control and sensitivity, with reduced hardware requirements and improved mechanical robustness, while allowing for high percentages of light to be guided through the PCB for effective compensation.
Implementation Method 1
The use of a printed circuit board (PCB) as an optical system to guide the compensation light from the compensation light source to the receiver
Implementation Method 2
An optical receiver receives a part of the light emitted by the two light sources with a photodiode, also designated hereafter as 'PD,' and converts it into current alternating signals
Data Source
AI summary
Opto-electronic measuring arrangement which is largely independent of extraneous light, comprising emitted and compensation light sources, which emit light time-sequentially and in a phased manner, wherein the emitted light is phase-shifted respectively by 180°. An optical receiver receives the light emitted by the emitted light source and reflected by the object being measured together with the light from the compensation light source. The actuation signals for the emitted and compensation light sources are controlled such that the synchronous signal difference occurring in the receiver between the different phases is reduced to zero. The optical coupling between the compensation light source and the receiver diode occurs mainly via an optical system in a printed circuit board on which the compensation light source and the receiver are arranged. The printed circuit board itself, i.e. the FR4 component thereof, may constitute the optical conductor between the compensation light source and receiver diode.