Air Filter With Density Gradient Urethane for Thickness Reduction

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Solution Overview

Problem

Existing air filters face challenges in reducing size and thickness while maintaining attachability and rigidity, often requiring a separate frame member for fixation, which complicates size reduction in devices like light source devices.

Innovation Solution

An air filter design incorporating a first urethane portion with air permeability and a higher-density second urethane portion, integrated through thermocompression bonding, eliminates the need for a frame member, ensuring attachability and rigidity even after thickness reduction, with optional features like metallic mesh, through holes, and adhesive layers for enhanced attachment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of stationary object

If air filter thickness is reduced, then device size can be reduced, but attachability and rigidity deteriorate

Engineering Contradiction:

Improveair filter thicknessVSAvoidattachability

Core Design Contradiction:

Length of stationary objectVSReliability

Solution Approach 1:

The air filter employs local quality by creating a density gradient within the filter structure. The first urethane portion has a first density while the second urethane portion has a second density higher than the first density. This localized variation in density provides enhanced rigidity and attachability in the second urethane portion while maintaining overall thickness reduction, resolving the contradiction between thinness and structural reliability.

Inventive Principle:

Principle #3Local quality

2Length of stationary object

If air filter thickness is reduced, then device size can be reduced, but rigidity deteriorates

Engineering Contradiction:

Improveair filter thicknessVSAvoidrigidity

Core Design Contradiction:

Length of stationary objectVSStrength

Solution Approach 1:

Inventive Principle:

Principle #3Local quality

3Reliability

If a separate frame member is added for fixation, then attachability is improved, but device complexity increases

Engineering Contradiction:

ImproveattachabilityVSAvoidair filter structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The air filter applies the merging principle by integrating the frame function directly into the filter body. The second urethane portion is formed integrally with the first urethane portion, eliminating the need for a separate frame member. This integration maintains attachability while reducing structural complexity and the number of components.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The second urethane portion serves multiple functions simultaneously: it provides structural support, enables attachment to the housing, and maintains filter integrity. By making the second urethane portion capable of performing multiple functions that would otherwise require separate components, the design reduces overall complexity while maintaining attachability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 air filter can be significantly reduced in thickness with ensured attachability and rigidity, facilitating easier handling and integration into smaller devices, such as light source devices, without compromising performance.

Implementation Method 1

The first urethane portion and the second urethane portion are integrated with each other by thermocompression bonding in a state where the second urethane portion is incorporated in the part of the first urethane portion

Methodology Applied

Scientific EffectThermocompression bonding:

Data Source

PatentEP3578246B1Air filter, light source device, and air filter manufacturing method

Publication Date: 2020.09.16 HAMAMATSU PHOTONICS KK

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AI summary

An air filter includes a first urethane portion made of polyurethane foam and having air permeability and a second urethane portion made of polyurethane foam and disposed so as to overlap with a part of the first urethane portion. The second urethane portion is higher in density than the first urethane portion. The first urethane portion and the second urethane portion are integrated with each other in a state where the second urethane portion is incorporated in the part of the first urethane portion.