MEMS Sensor Calibration Using Thermal Spreader

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Solution Overview

Problem

MEMS devices are prone to unreliable calibration due to external influences, which can vary with the environment, making periodic calibration necessary but challenging.

Innovation Solution

A MEMS device with a thermal element configured to adjust temperature, using a thermally conductive device spreader on the top surface and thermally conductive board spreaders to maintain uniform temperature, along with a Peltier thermal element for heating and cooling, to enhance calibration reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a thermal element is used to adjust temperature for calibration, then calibration reliability is improved, but temperature uniformity across the device surface deteriorates

Engineering Contradiction:
Improvecalibration reliabilityVSAvoidtemperature uniformity
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

A thermal spreader layer is introduced as an intermediary component between the thermal element and the MEMS device. This thermal spreader receives heat from the thermal element and distributes it uniformly across the device surface, mediating the temperature distribution to achieve both reliable calibration and uniform temperature.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The thermal characteristics of the device are modified by adding a thermal spreader layer with specific thermal conductivity properties. This changes the heat distribution parameter from concentrated (at the thermal element) to uniform (across the device surface), enabling reliable calibration without temperature gradients.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If periodic calibration is performed to account for environmental changes, then sensor accuracy is improved, but device complexity increases

Engineering Contradiction:
Improvesensor accuracyVSAvoidcalibration system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system performs self-calibration by automatically controlling the thermal element and thermal spreader to maintain the desired temperature conditions. The calibration process is autonomous, reducing the need for external intervention and simplifying the overall system operation while maintaining high sensor accuracy.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

Temperature stabilization is achieved before calibration measurements are taken. The thermal element and spreader pre-establish the required temperature uniformity across the device surface, ensuring that calibration occurs under optimal and consistent conditions, thereby improving accuracy without adding complex real-time adjustment mechanisms.

Inventive Principle:
Principle #10Preliminary action

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 solution ensures consistent sensor performance by maintaining uniform temperature, allowing for precise calibration and reducing the impact of environmental changes on sensor accuracy.

Implementation Method 1

The thermal element may be a peltier thermal element. The thermal element may be configured to selectively heat and cool the MEMS device.

Methodology Applied
Scientific EffectPeltier effect: Peltier Effect

Implementation Method 2

a device thermal spreader of thermally conductive material is disposed over a top surface of the MEMS device to substantially maintain a uniform temperature about a top surface of the MEMS device

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

at least one board thermal spreader is disposed about the circuit board to substantially maintain a uniform temperature about the circuit board

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP3233716B1Device and method for sensor calibration
Publication Date: 2023.10.11 INVENSENSE INC
  • EP3233716B1 patent drawingFigure 1
  • EP3233716B1 patent drawingFigure 2
  • EP3233716B1 patent drawingFigure 3

AI summary

A device and method for a MEMS device with at least one sensor is disclosed. A thermal element is disposed adjacent the MEMS device to selectively adjust a temperature of the MEMS device. A calibration operation is initiated for the sensor to determine a correction value to be applied to the sensor measurement based on the temperature. The correction value is stored.