MEMS Sensor Heater for Temperature Offset Compensation

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Solution Overview

Problem

Electronic sensors face performance degradation due to exposure to external environments, such as water and varying temperatures, with existing calibration algorithms failing to address temperature coefficient offsets after soldering on a board.

Innovation Solution

Integration of a heater element within the sensor device to generate heat and calibrate the sensor post-soldering, addressing temperature coefficient offsets and removing liquid by evaporating water droplets on the deformable membrane.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If calibration algorithm is used before soldering the sensor, then performance degradation from water exposure is addressed, but temperature coefficient offset after soldering is not compensated

Engineering Contradiction:
Improvesensor performance stabilityVSAvoidtemperature compensation capability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The heater element is integrated into the sensor device to enable preliminary heating and calibration actions before the sensor is soldered onto the board. This preliminary action allows the sensor to be calibrated at a controlled temperature, and the heater can subsequently compensate for temperature coefficient offsets after soldering by maintaining or adjusting the sensor temperature.

Inventive Principle:
Principle #10Preliminary action

2Object-affected harmful factors

If sensor is exposed to water droplets on the membrane, then liquid contact is detected, but performance degradation and offset occur

Engineering Contradiction:
Improveliquid detection capabilityVSAvoidsensor performance
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The heater element, which generates thermal energy, is used to evaporate water droplets that contact the deformable membrane. By converting the harmful effect of liquid exposure into a beneficial drying action, the sensor performance is restored and liquid-induced offsets are eliminated without requiring separate detection and removal systems.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 effectively stabilizes sensor performance by compensating for temperature-dependent shifts and removing liquid-induced offsets, ensuring consistent operation across different environmental conditions.

Implementation Method 1

heat is generated by ohmic heating as an electric current passes through at least part of one of the structural layers of the device

Methodology Applied
Scientific EffectOhmic heating: Joule Heating

Implementation Method 2

removing liquid by evaporating water droplets on the deformable membrane

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP3807209B1Sensor with integrated heater
Publication Date: 2024.04.24 INVENSENSE INC
  • EP3807209B1 patent drawingFigure 1A
  • EP3807209B1 patent drawingFigure 1B
  • EP3807209B1 patent drawingFigure 2

AI summary

A device includes a microelectromechanical system (MEMS) sensor die comprising a deformable membrane, a MEMS heating element, and a substrate. The MEMS heating element is integrated within a same layer and a same plane as the deformable membrane. The MEMS heating element surrounds the deformable membrane and is separated from the deformable membrane through a trench. The MEMS heating element is configured to generate heat to heat up the deformable membrane. The substrate is coupled to the deformable membrane.