Infrared Sensor Filter Recess Design for Adhesive Contamination Control

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Solution Overview

Problem

Infrared sensors face contamination issues due to adhesive leakage when using flat surfaces for optical filters and holders, leading to potential contamination of the optical filters during adhesion.

Innovation Solution

An infrared-sensor filter member with a recess portion formed on one surface of the optical filter and a side wall formed by a separate member, where the recess portion's inner side surface is inclined to prevent adhesive contamination, and the member's emissivity is optimized to accurately determine infrared ray doses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a flat surface is used for adhesion between optical filter and holder, then the manufacturing process is simple, but adhesive leakage contaminates the optical filter

Engineering Contradiction:

Improveadhesion process simplicityVSAvoidoptical filter contamination

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

A recess portion is formed in advance on the holder surface before adhesion. This preliminary structural preparation allows the optical filter to be positioned within the recess, creating a built-in protective structure that prevents adhesive from reaching and contaminating the optical filter surface during the adhesion process.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The recess portion acts as an intermediary structure between the holder and the optical filter. It provides a controlled interface that separates the adhesion zone from the optical filter surface, allowing adhesive to be applied to the holder within the recess while preventing direct contact with the optical filter, thus mediating the adhesion process without contamination.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Device complexity

If the optical filter and holder are adhered directly without a recess, then the device structure is simple, but adhesive leakage occurs and contaminates the optical filter

Engineering Contradiction:

Improvestructure simplicityVSAvoidoptical filter cleanliness

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The recess portion is formed in advance on the holder as a preliminary structural feature. This simple yet effective preparation creates a natural barrier that prevents adhesive leakage onto the optical filter, improving reliability without requiring complex additional components or mechanisms.

Inventive Principle:

Principle #10Preliminary action

3Object-affected harmful factors

If a recess portion with inclined inner side surface is formed, then adhesive contamination is prevented, but the manufacturing process becomes more complex

Engineering Contradiction:

Improveadhesive contamination preventionVSAvoidrecess structure complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The recess portion features an inclined inner side surface that slopes toward the bottom. This curved/angled geometry is designed to guide and redirect adhesive flow away from the optical filter surface during adhesion, using geometric curvature to achieve contamination prevention with minimal structural complexity.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The recess portion introduces a depth dimension to the otherwise flat holder surface. By creating a three-dimensional recess structure with inclined surfaces, the design utilizes the vertical dimension to control adhesive flow paths, preventing contamination while maintaining relative structural simplicity.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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

Prevents optical filter contamination by adhesive, enhances accuracy in infrared ray detection, and allows for a compact sensor design with improved thermal management.

Implementation Method 1

a wavelength selective filter that selectively transmits a light having a specific wavelength to a sensor element

Methodology Applied

Scientific EffectWavelength selective filtering: Filter (optical)

Implementation Method 2

when detecting a predetermined infrared ray using an infrared sensor element

Methodology Applied

Scientific EffectInfrared detection: Photoelectric Effect

Data Source

PatentUS9638576B2Infrared-sensor filter member, manufacturing method thereof, infrared sensor, and manufacturing method thereof

Publication Date: 2017.05.02 ASAHI KASEI MICRODEVICES CORP

AI summary

An infrared-sensor filter member includes an optical filter disposed in an opening portion of a second member and a first member. The infrared-sensor filter member includes a recess portion formed from a light-incident surface of the optical filter and the first member. At least a part of a bottom surface of the recess portion is formed by the light-incident surface and side walls of the recess portion, which are formed by the first member.