Magnetic Target Weight Sensor for Compact High-Precision Measurement

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing weight sensors, particularly those used in domestic settings for measuring small quantities like coffee, face challenges with accuracy and reliability due to mechanical deformation, temperature sensitivity, and susceptibility to spillage, especially when handling hot products.

Innovation Solution

A compact weight sensor design utilizing a flexible target piece and a sensing element that detects magnetic field changes, integrated with a semiconductor package, allowing for accurate position sensing and robustness against stray fields, with optional temperature compensation and a low profile footprint.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If magnetic field sensing is used, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improveweight measurement accuracyVSAvoidsensor structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines the magnetic target, flexible piece, and sensing element into a single integrated force sensor unit. The target is embedded in the flexible piece, which is directly integrated on the semiconductor package, merging multiple components into one compact assembly that maintains high measurement precision while reducing overall device complexity

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent embeds the magnetic target within the flexible piece, creating a nested structure where the target is contained inside the flexible material. This nesting approach allows the sensing system to maintain high measurement precision while minimizing the footprint and simplifying the overall device structure

Inventive Principle:
Principle #7Nested doll (Nesting)

2Ease of operation

If the sensor is made compact, then ease of operation is improved, but manufacturing precision requirements increase

Engineering Contradiction:
ImproveintegrabilityVSAvoidalignment precision
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent merges the target and flexible piece into a single integrated component that is directly mounted on the semiconductor package. This integration eliminates the need for separate alignment steps between multiple components, thereby improving ease of operation through compactness while reducing manufacturing precision requirements

Inventive Principle:
Principle #5Merging (Combining)

3Device complexity

If the flexible piece is made smaller, then device complexity is reduced, but measurement precision may deteriorate

Engineering Contradiction:
ImprovefootprintVSAvoidweight sensing accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent optimizes the parameters of the flexible piece, including its thickness and material properties, to achieve the right balance between size and sensitivity. By carefully selecting the flexibility parameter of the material and the thickness of the piece, the sensor maintains high measurement precision in a compact form factor

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 solution provides a highly accurate, compact, and integrable weight sensor capable of measuring small weights with high resolution, resistant to temperature changes and spillage, suitable for domestic appliances like coffee grinders and brewers.

Implementation Method 1

The sensing element is configured to sense changes of the magnetic field from motion of the target piece with respect to the sensing element

Methodology Applied
Scientific EffectMagnetic field sensing: Magnetic Field

Implementation Method 2

The flexible piece comprises the target piece for providing motion of the target piece upon placement of a product to be weighted over the flexible piece

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP4113086A1Force sensing scale with target
Publication Date: 2023.01.04 MELEXIS TECHNOLOGIES SA
  • EP4113086A1 patent drawingFigure 1~2
  • EP4113086A1 patent drawingFigure 3~4
  • EP4113086A1 patent drawingFigure 5

AI summary

A weight sensor comprises a sensing system including a target piece and a sensing element, configured to provide changes of a magnetic field, being generated by motion of the target piece. The sensing element senses these changes and provides a signal representative of the position of the target piece. An integrated circuit with processing means can process signals from the sensing element. The flexible piece receives a force stimulus, so that upon exerting a force on the flexible piece by a product due to the weight of said product, the displacement of the target piece with respect to sensing elements can be sensed.