Optical Probe Head for Galvanic Isolation

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing measurement systems face challenges in accurately measuring small signals at high reference potentials due to non-linear frequency responses and incompatibility with direct current signals, particularly when using transformers for galvanic isolation.

Innovation Solution

A probe arrangement with a probe head and coupler utilizing optical links for complete electrical isolation, where the probe head is powered optically and signals are transmitted over a wide frequency range using multiple optical channels, allowing for linear signal transmission and galvanic isolation without the limitations of transformers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If transformers are used for galvanic isolation, then electrical isolation is achieved, but frequency response becomes non-linear and direct current transmission is not possible

Engineering Contradiction:

Improvegalvanic isolationVSAvoidfrequency response linearity

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent replaces the electromagnetic transformer system with an optical transmission system. The probe head converts electrical signals to optical signals using a light source, transmits them through optical fibers to the probe coupler, and converts them back to electrical signals. This substitution eliminates the non-linear frequency response and DC transmission limitations of transformers while maintaining galvanic isolation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces optical signals as an intermediary medium between the probe head and probe coupler. Instead of direct electrical coupling through transformers, the system uses optical fibers as intermediaries to transmit information, achieving galvanic isolation while preserving signal fidelity across the entire frequency range including DC.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If transformers are used for galvanic isolation, then electrical isolation is achieved, but assembly space and weight increase

Engineering Contradiction:

Improvegalvanic isolationVSAvoidprobe system weight

Core Design Contradiction:

ReliabilityVSWeight of stationary object

Solution Approach 1:

The patent replaces heavy electromagnetic transformer components with lightweight optical fibers and compact optoelectronic converters. The optical fiber cable weighing approximately 50g is significantly lighter than traditional transformer-based isolation systems, reducing both the weight and physical footprint of the probe system while maintaining galvanic isolation functionality.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If optical links are used for signal transmission, then linear frequency response and DC transmission are achieved, but system complexity increases

Engineering Contradiction:

Improvefrequency response linearityVSAvoidoptical interface complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines multiple optical functions into integrated optoelectronic modules at both the probe head and probe coupler. The probe head integrates the light source, modulator, and optical coupling, while the probe coupler integrates the optical-to-electrical converter and signal processing. This merging approach reduces the overall system complexity despite the advanced functionality provided by optical transmission.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The optical transmission system serves multiple functions simultaneously: it provides galvanic isolation, achieves linear frequency response across the entire spectrum including DC, enables bidirectional communication, and allows for flexible signal routing. This multi-functionality consolidates what would otherwise require multiple separate systems, thereby reducing overall complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 precise, isolated measurement of electrical signals with high reference potentials and direct current components, achieving linear frequency response and reducing the physical size and weight of the measurement system.

Implementation Method 1

The first optical interface (21) is configured to convert the received optical power signal to electrical power

Methodology Applied

Scientific EffectPhotoelectric Effect: Photoelectric Effect

Implementation Method 2

Each of the one or more second optical interfaces (22a, 22b) is configured to transmit an optical signal based on the electrical measurement signal received by the probe tip

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentUS11187730B2Probe head, probe coupler and probe arrangement

Publication Date: 2021.11.30 ROHDE & SCHWARZ GMBH & CO KG

AI summary

The present invention provides an electrically isolated acquisition of a measurement signal by means of a measurement probe. For this purpose, a probe arrangement is provided with a probe head for electrically measuring a signal. The probe head is coupled to a probe coupler via optical links. In particular, optical links are used for power supply of the probe head and for forwarding optical signals corresponding to the measured electrical signal.