Optical Measuring Device for Dental Plaque Detection

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Solution Overview

Problem

Conventional optical methods struggle to accurately detect small amounts of dental plaque due to interference from environmental light and distance variations, leading to measurement errors and difficulties in incorporating complex optical filters into toothbrushes.

Innovation Solution

An optical measuring device that uses multiple light sources emitting different wavelengths to irradiate a tooth and a detection unit to calculate the amount of fluorescent substance based on the intensity differences between fluorescence generated by these wavelengths, allowing for precise separation of intrinsic and plaque-related fluorescence.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional single-wavelength fluorescence detection is used, then the detection system is simple, but measurement precision deteriorates due to interference from intrinsic tooth fluorescence and environmental light

Engineering Contradiction:
Improveplaque detection accuracyVSAvoidoptical system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the fluorescence detection into multiple wavelength bands by using a plurality of wavelength selection filters (first wavelength selection filter and second wavelength selection filter) that separate the emitted light into different wavelength ranges. This allows independent measurement of fluorescence intensity at each wavelength, enabling differentiation between intrinsic tooth fluorescence and plaque-related fluorescence while maintaining a relatively simple optical system structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the detection parameter from single-wavelength to multi-wavelength fluorescence measurement. By measuring fluorescence intensity at multiple wavelengths and calculating the difference between these intensities, the system can eliminate the influence of intrinsic tooth fluorescence and environmental light interference, thereby improving measurement precision without requiring complex optical filtering arrangements.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If optical filters are added to improve detection accuracy, then measurement precision improves, but device complexity increases making toothbrush integration difficult

Engineering Contradiction:
Improvefluorescence detection accuracyVSAvoidtoothbrush integration ease
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent uses wavelength selection filters to segment the fluorescence spectrum into multiple wavelength bands. This segmentation approach allows the system to distinguish between different fluorescence sources (intrinsic tooth fluorescence vs. plaque fluorescence) using relatively simple optical components that can be integrated into toothbrushes, avoiding the need for complex optical filter systems.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent measures fluorescence intensity at multiple wavelengths and uses the difference between these measurements to calculate plaque amount. This approach creates a simplified detection model where the plaque signal is extracted as a difference value, effectively copying the essential information needed for accurate detection while eliminating the need for complex real-time spectral analysis hardware.

Inventive Principle:
Principle #26Copying

3Reliability

If conventional fluorescence measurement is used, then the system is simple, but reliability deteriorates due to environmental light interference and distance variations

Engineering Contradiction:
Improvedetection stabilityVSAvoidoptical system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the fluorescence detection into multiple wavelength bands using wavelength selection filters. By measuring and comparing fluorescence intensities at different wavelengths, the system can identify and eliminate the influence of environmental light interference and intrinsic tooth fluorescence, thereby improving detection reliability without requiring complex environmental control mechanisms or distance stabilization systems.

Inventive Principle:
Principle #1Segmentation

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

This approach enables effective detection of small amounts of dental plaque with reduced measurement errors and a simpler configuration suitable for integration into toothbrushes, improving plaque detection accuracy and usability.

Implementation Method 1

a first light source that emits light having a first wavelength, a second light source that emits light having a second wavelength longer than the wavelength of the light emitted by the first light source, a detection unit that detects intensities of fluorescence generated when the same sample is irradiated with the light having the first wavelength and the light having the second wavelength

Methodology Applied
Scientific EffectFluorescence: Fluorescence

Data Source

PatentEP3267182B1Optical measuring device and toothbrush provided with same
Publication Date: 2022.02.23 CITIZEN WATCH CO LTD
  • EP3267182B1 patent drawingFigure 1~2
  • EP3267182B1 patent drawingFigure 3~4B
  • EP3267182B1 patent drawingFigure 5A~5C

AI summary

Provided is an optical measuring device that can properly detect a small amount of dental plaque, can be easily incorporated into a toothbrush, and has a simple configuration. The optical measuring device includes a plurality of light sources that irradiate a sample with light having a plurality of wavelengths different from each other, respectively, a detection unit that detects intensities of examined light generated when the sample is irradiated with the light having the plurality of wavelengths, and a control unit that calculates an amount of fluorescent substance to be measured, based on the intensities of the examined light detected by the detection unit in response to the light having the plurality of wavelengths.