Drain Pan Dirt Detection Using Blue-Wavelength Lighting

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Solution Overview

Problem

Conventional air treatment devices face difficulties in specifying the dirtied state of inner surfaces, particularly due to biofilm with pale pink, pale brown, or pale yellow colors, which are challenging to distinguish from the white surface using conventional photography methods.

Innovation Solution

Incorporating a lighting device that emits visible light with a maximum peak wavelength between 400 nm to 500 nm, allowing dirt on the inner surfaces to absorb these wavelengths, resulting in lower brightness in image data and making it easier to differentiate between clean and dirty areas.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional photographing methods are used to capture the inner surface of the tray, then the image data can be obtained, but the dirtied state (pale pink, pale brown, or pale yellow biofilm) cannot be clearly specified or distinguished from the white surface

Engineering Contradiction:
Improvedirt detection accuracyVSAvoidbrightness contrast information
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent changes the lighting parameter by using a light source with a specific wavelength (maximum peak wavelength between 400 nm to 500 nm) instead of conventional lighting. This wavelength parameter change causes dirt to absorb light differently, creating sufficient brightness contrast in the captured images to distinguish the pale-colored biofilm from the white tray surface.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent utilizes the color absorption properties of dirt by selecting a light wavelength (400-500 nm) that is strongly absorbed by pale pink, pale brown, and pale yellow biofilm. This creates a brightness difference between dirty and clean areas, effectively using color absorption characteristics to solve the detection problem.

Inventive Principle:
Principle #32Color changes

2Area of stationary object

If the photographing device captures the entire inner surface including water areas, then comprehensive coverage is achieved, but the water surface reflects light and interferes with dirt detection

Engineering Contradiction:
Improvephotographing coverage areaVSAvoidwater surface reflection interference
Core Design Contradiction:
Area of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The patent performs photographing at a specific timing - after water discharge from the drain pan is completed. This preliminary action of waiting for water discharge eliminates the water surface reflection interference before capturing the image, allowing clear detection of the entire inner surface including areas that would otherwise be obscured by water.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If multiple photographing devices are used to capture different angles and surfaces, then comprehensive dirt detection is achieved, but the device complexity increases

Engineering Contradiction:
Improvedirt detection comprehensivenessVSAvoidphotographing system structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent uses a single photographing device that is capable of capturing multiple surfaces (bottom surface and side surfaces) of the drain pan. This multi-functional approach allows one device to perform the work that would otherwise require multiple devices, maintaining detection comprehensiveness while minimizing system complexity.

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

Solution Approach 2:

The photographing device is designed to be movable or adjustable, enabling it to capture images of different surfaces and angles. This dynamic capability allows a single device to adapt its position and orientation to photograph various parts of the drain pan, achieving comprehensive coverage without requiring multiple fixed devices.

Inventive Principle:
Principle #15Dynamics

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 clear depiction of dirt on the inner surfaces, including biofilm, by creating a significant brightness difference in image data, facilitating the assessment of the dirtied state.

Implementation Method 1

Dirt in pale pink, pale brown, or pale yellow tending to adhere to the inner surface of the tray absorbs most of maximum peak wavelength components of the visible light emitted from the lighting device (72)

Methodology Applied
Scientific EffectLight absorption: Absorption (EM radiation)

Data Source

PatentEP4016183B1Air treatment device
Publication Date: 2024.03.13 DAIKIN INDUSTRIES LTD
  • EP4016183B1 patent drawingFigure 1
  • EP4016183B1 patent drawingFigure 2
  • EP4016183B1 patent drawingFigure 3

AI summary

An air treatment device includes a casing (20), a drain pan (50) provided in the casing (20), a camera (70) configured to capture an inner surface of the drain pan (50) to obtain image data, and a lighting device (72) configured to apply, to a photographing target of the camera (70), visible light having a maximum peak wavelength in a wavelength band from 400 nm to 500 nm.