PCB Slit for Fluorescence Crosstalk Suppression

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Solution Overview

Problem

Current fluorescence-optical measuring systems for blood parameters face challenges in minimizing optical crosstalk between excitation and detection sides, leading to increased complexity, size, and manufacturing costs, as well as impaired usability due to the need for complex mechanical structures and special geometries to separate optical signals.

Innovation Solution

The solution involves arranging all optoelectronic elements in a single plane on a printed circuit board with a gap or slit between the radiation source and detector, using metallization to suppress crosstalk, and incorporating a radiation-suppressing housing with specific transmissive areas and web elements to minimize optical crosstalk, allowing for a more compact and cost-effective design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If complex mechanical structures and special geometries are used to separate optical signals, then optical crosstalk is minimized, but device complexity and structural height increase

Engineering Contradiction:
Improveoptical signal separationVSAvoidmechanical structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical structures for optical separation with a planar optical filter layer integrated on the circuit board. Instead of using three-dimensional mechanical geometries to block or guide light, the invention uses two-dimensional optical filtering materials (such as absorbing or wavelength-selective layers) deposited or laminated on the board surface, thereby eliminating the need for complex mechanical housings and geometric arrangements while achieving effective optical signal separation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent combines the optical separation function with the circuit board structure itself by integrating optical filter layers directly onto the board. The optical filtering elements are merged with the mechanical support structure, eliminating separate optical isolation components. This integration reduces overall device complexity while maintaining effective separation of excitation and detection light paths.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If complex mechanical structures and special geometries are used to separate optical signals, then optical crosstalk is minimized, but manufacturing costs increase

Engineering Contradiction:
Improveoptical signal separationVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces expensive precision-machined mechanical optical isolation structures with planar optical filter layers that can be manufactured using standard PCB fabrication techniques, lamination processes, or thin-film deposition. This substitution dramatically reduces manufacturing complexity and cost while achieving the same optical separation performance.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the approach from three-dimensional geometric parameter optimization to two-dimensional optical property parameter optimization. Instead of carefully designing mechanical geometries to block light, the invention uses optical filter layers with specific absorption coefficients, wavelengths, and thicknesses, which can be more easily controlled and manufactured with standard industrial processes.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If all optoelectronic elements are arranged in a single plane, then manufacturing and assembly are simplified, but optical crosstalk between excitation and detection sides increases

Engineering Contradiction:
Improveassembly simplicityVSAvoidoptical signal separation
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent introduces optical filter layers as intermediary elements between the light source and detector on the same circuit board. These filter layers act as mediators that selectively transmit or block specific wavelengths, enabling effective optical separation even when excitation and detection elements are coplanar. The intermediary filter layer prevents direct optical coupling while allowing the simplified planar arrangement to be maintained.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies different optical properties to different regions of the circuit board by placing specific optical filter layers at strategic locations. The optical filters are positioned locally between the light source and detector to block stray light paths, while other regions of the board maintain their electrical and mechanical functions. This localized application of optical filtering enables effective crosstalk suppression without compromising the overall planar design.

Inventive Principle:
Principle #3Local quality

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 reduces optical crosstalk, simplifies manufacturing and assembly, decreases the structural height of the device, and enhances usability by minimizing the overall size and production costs while maintaining accurate signal separation.

Implementation Method 1

a radiation source (e.g., light source) for the excitation radiation

Methodology Applied
Scientific EffectLight emission from radiation source: Light Emitting Diode

Implementation Method 2

measuring fluid parameters (such as blood parameters) on a fluorescence-optical basis

Methodology Applied
Scientific EffectFluorescence: Fluorescence

Implementation Method 3

a detector for the detection of the fluorescence radiation

Methodology Applied
Scientific EffectOptical detection: Photoelectric Effect

Implementation Method 4

the printed circuit board contains a gap or a slit for suppressing conduction of light

Methodology Applied
Scientific EffectLight absorption and blocking: Absorption (EM radiation)

Data Source

PatentEP3504537B1Device for measuring fluorescence using a printed circuit board with mounted light source and detector, wherein the printed circuit board contains a slit for suppressing conduction of light
Publication Date: 2021.12.15 B BRAUN MELSUNGEN AG
  • EP3504537B1 patent drawingFigure 1~3
  • EP3504537B1 patent drawingFigure 4~6
  • EP3504537B1 patent drawingFigure 7~9

AI summary

The invention relates to a converter device and to a method for measuring at least one fluid parameter of a fluid located in a flow measuring cell. The converter device is equipped with a radiation source (101) for generating an excitation radiation and a detector (102) arranged on the same plane as the radiation source (101) for detecting fluorescence radiation which is excited by the excitation radiation in the flow measuring cell and reflected back after the fluid flows through the flow measuring cell. A radiation-suppressing element (104) is arranged in a direct radiation path between the radiation source (101) and the detector (102) or in a direct radiation path between a fluorescence source of an adjacent measuring channel and the detector.