Toothbrush Angle Detection via Force Sensing

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Solution Overview

Problem

Users often brush their teeth at angles far from perpendicular, leading to inefficient plaque removal as many bristles lose contact or are positioned ineffectively, reducing the cleaning efficiency of power toothbrushes.

Innovation Solution

A toothbrush equipped with a first and second force sensor to measure forces at different angles relative to a tooth, coupled with a processing unit that determines the current brushing angle and provides user feedback to encourage optimal brushing angles through audible or visual cues.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If users brush at extreme angles (up to 70 degrees from perpendicular), then they can reach difficult-to-access tooth surfaces, but brushing efficiency drops dramatically as bristles lose contact with teeth

Engineering Contradiction:
Improveability to reach different tooth surfacesVSAvoidbrushing efficiency
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent employs force sensors to detect the contact force between bristles and teeth, providing real-time feedback to the user via visual or audible signals. When the brushing angle becomes too extreme and bristle contact is lost, the system alerts the user to adjust their brushing angle, thereby maintaining optimal brushing efficiency while still allowing access to difficult tooth surfaces.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If multiple force sensors are added to detect brushing angle, then brushing angle detection accuracy improves, but device complexity increases

Engineering Contradiction:
Improvebrushing angle detection accuracyVSAvoidnumber of force sensors
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

Instead of adding multiple force sensors at different spatial positions, the patent calculates brushing angle by analyzing force data from a single force sensor in combination with brushhead orientation data from an accelerometer or gyroscope. This transforms a spatial measurement problem into a computational problem, achieving accurate angle detection without increasing sensor quantity.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent introduces a processing unit that acts as an intermediary, computing the brushing angle by combining force magnitude data with brushhead orientation data from motion sensors. This computational approach allows accurate angle detection without requiring direct physical measurement at multiple angles, thereby reducing device complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 encourages users to brush at favorable angles, enhancing plaque removal efficiency by ensuring bristles maintain optimal contact with teeth surfaces, thereby improving cleaning effectiveness.

Implementation Method 1

a first force sensor for measuring a first force exerted by the brushhead at a first angle relative to a tooth

Methodology Applied
Scientific EffectForce sensing: Force

Implementation Method 2

a second force sensor for measuring a second force exerted by the brushhead at a second angle relative to the tooth

Methodology Applied
Scientific EffectForce sensing: Force

Data Source

PatentEP3583913B1Toothbrush with automatic detection of brushing angle
Publication Date: 2022.02.09 KONINKLIJKE PHILIPS NV
  • EP3583913B1 patent drawingFigure 1~2
  • EP3583913B1 patent drawingFigure 3~4
  • EP3583913B1 patent drawingFigure 5

AI summary

A A method of operating a toothbrush (10) having a brushhead (18), comprising: generating first information indicative of a first force exerted by the brushhead at a first angle relative to a tooth and second information indicative of a second force exerted by the brushhead at a second angle relative to the tooth, the second angle being different than the first angle; determining information regarding a current brushing angle of the brushhead based on the first information and the second information; and providing user perceptible feedback based on the determined information regarding the current brushing angle