Piezochromic Polymer Toothbrush Force Indicator

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Solution Overview

Problem

Existing toothbrush designs that indicate excessive brushing force often require batteries or complex circuitry, leading to manufacturing difficulties, hygiene issues, and increased costs, while also being cumbersome and expensive to produce.

Innovation Solution

A toothbrush incorporating a piezochromic polymer that changes color in response to brushing force, eliminating the need for a power source or electrical circuitry, with the polymer visible through a transparent portion of the handle, allowing users to see if they are applying the correct amount of pressure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If electrical circuits and batteries are used to power the indicator, then the indicator can provide clear signals to the user, but the device becomes more complex and requires frequent battery replacement in a damp environment

Engineering Contradiction:
Improveindicator signal reliabilityVSAvoidcircuit complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces electrical circuits and batteries with a purely mechanical indicator system. The indicator is integrated into the brush neck structure and responds mechanically to brushing force through flexing, eliminating the need for electrical power sources and complex circuitry while maintaining reliable indication functionality.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The indicator system is self-activating through the mechanical flexing of the brush neck during brushing. The indicator automatically responds to the force applied by the user without requiring external power sources, control systems, or maintenance, making the system self-sufficient and suitable for the damp brushing environment.

Inventive Principle:
Principle #25Self-service

2Ease of repair

If a removable cover is added to access the battery and circuitry, then battery replacement is enabled, but hygiene is compromised due to gaps and debris collection

Engineering Contradiction:
Improvebattery replacementVSAvoidhygiene contamination
Core Design Contradiction:
Ease of repairVSObject-affected harmful factors

Solution Approach 1:

The indicator system is designed to be maintenance-free with no batteries or replaceable components. The integrated mechanical indicator remains permanently sealed within the brush structure, eliminating the need for removable covers and preventing any hygiene contamination while maintaining full functionality throughout the brush's lifetime.

Inventive Principle:
Principle #25Self-service

3Adaptability or versatility

If miniature components are fitted into a small cavity in the brush handle, then the indicator can be integrated, but manufacturing becomes difficult and expensive

Engineering Contradiction:
Improveindicator integrationVSAvoidmanufacturing complexity
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent merges the indicator function directly into the brush neck structure itself, eliminating the need for separate miniature components and cavities. The indicator becomes an integral part of the existing brush anatomy, allowing for simple co-molding or integration during standard brush manufacturing processes.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The brush neck serves multiple functions: it provides structural connection between handle and head, and simultaneously houses the indicator mechanism. This multi-functionality eliminates the need for additional components and cavities, simplifying manufacturing while achieving indicator integration.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Device complexity

If the indicator is made as an attachment to the brush, then the indicator mechanism can be separate, but the brush becomes awkwardly shaped and unnatural to use

Engineering Contradiction:
Improvemechanical separationVSAvoidbrush ergonomics
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The patent combines the indicator mechanism with the brush neck into a single integrated structure. This merging eliminates the awkward appearance and unnatural feel that would result from an attached indicator, while the indicator remains mechanically distinct within the integrated design for proper functionality.

Inventive Principle:
Principle #5Merging (Combining)

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

Provides a visible signal for suitable brushing force without the need for batteries or complex circuitry, making the toothbrush more hygienic, cost-effective, and easier to manufacture, while allowing users to adjust their brushing technique effectively.

Implementation Method 1

a piezochromic polymer which changes colour in response to brushing force

Methodology Applied
Scientific EffectPiezochromism:

Data Source

PatentEP2680721B1Toothbrush including a device for indicating brushing force
Publication Date: 2017.11.01 COLGATE PALMOLIVE CO
  • EP2680721B1 patent drawingFigure 1~3
  • EP2680721B1 patent drawingFigure 4~6
  • EP2680721B1 patent drawingFigure 7~8

AI summary

A toothbrush that includes a piezochromic polymer or a proximity dye based polymer effective to emit an optical signal indicative of brushing force.