NV Diamond Quantum Sensor Temperature Compensation for Magnetic Sensing

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Solution Overview

Problem

Quantum sensor systems using NV diamond structures face errors in magnetic field measurement due to temperature changes, particularly when light with a specific wavelength is directed onto the NV diamond structure, leading to inaccuracies in the measurement.

Innovation Solution

A quantum sensor system is designed with a magnetic sensor module and a main circuit that includes first and second temperature sensors to measure magnetic fields based on temperature differences, adjusting frequency bands and resonant frequencies to compensate for temperature variations, using a lock-in amplifier to amplify signals and an electromagnetic wave blocking sheet to shield noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If light having a wavelength of 532 nm is directed onto the NV diamond structure to measure magnetic field, then magnetic field measurement capability is enabled, but temperature in the vicinity of the NV diamond structure is increased causing measurement error

Engineering Contradiction:
Improvemagnetic field measurement capabilityVSAvoidtemperature increase in vicinity of NV diamond structure
Core Design Contradiction:
Measurement precisionVSTemperature

Solution Approach 1:

A heat dissipation structure is introduced as an intermediary between the light source and the NV diamond structure. This mediator absorbs and conducts away the heat generated by the 532 nm light, preventing temperature increase at the NV diamond while allowing the light to continue exciting the quantum system for magnetic field measurement.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system is segmented into distinct functional components: a light source module, a heat dissipation module, and an NV diamond structure module. The heat dissipation structure is positioned between the light source and the NV diamond, creating spatial separation that allows independent optimization of each component's function.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If temperature compensation is implemented using multiple temperature sensors and frequency band adjustment, then measurement accuracy is improved, but device complexity is increased

Engineering Contradiction:
Improvemagnetic field measurement accuracyVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

Temperature sensors continuously monitor the temperature at the NV diamond structure and the main circuit, feeding this information back to the control unit. The control unit automatically adjusts the frequency band and resonant frequency based on the temperature difference, creating a closed-loop feedback system that maintains measurement accuracy without manual intervention.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically changes operational parameters (frequency band and resonant frequency) based on temperature conditions. By adjusting these parameters in response to temperature variations, the system compensates for temperature-induced measurement errors while using relatively simple sensor and control components.

Inventive Principle:
Principle #35Parameter changes

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

The system effectively reduces measurement errors caused by temperature changes, enabling precise magnetic field detection by adjusting frequency bands and resonant frequencies, thus improving measurement accuracy.

Implementation Method 1

When an external magnetic field exists in the axial direction of the nitrogen-vacancy center within the NV diamond structure, the superposition of the spin quantum states m_s = +1 and m_s = -1 of the nitrogen-vacancy center disappears due to the Zeeman effect, and the spin quantum states exist at different energy levels.

Methodology Applied
Scientific EffectZeeman effect: Zeeman Effect

Implementation Method 2

a lock-in amplifier configured to amplify a signal from the photodetector and output the resulting output signal

Methodology Applied
Scientific EffectSignal amplification:

Implementation Method 3

an electromagnetic wave blocking sheet arranged on a substrate of the main circuit in such a manner to shield power noise

Methodology Applied
Scientific EffectElectromagnetic shielding:

Data Source

PatentEP4729971A1Quantum sensor system
Publication Date: 2026.04.22 LG ELECTRONICS INC
  • EP4729971A1 patent drawingFigure 1(a)~1(c)
  • EP4729971A1 patent drawingFigure 2
  • EP4729971A1 patent drawingFigure 3(a)~3(b)

AI summary

This quantum sensor system comprises: a magnetic sensor module disposed spaced apart from a magnetic device to measure a magnetic field from the magnetic device and having a second temperature sensor; and a main circuit operably coupled to the magnetic sensor module and having a first temperature sensor. The main circuit is configured to measure the magnetic field in a specific frequency band on the basis of the temperature value difference between a first temperature value measured by the first temperature sensor and a second temperature value measured by the second temperature sensor.