Laser Welding Liquid Flow-Path Member Using Selective UV Blocking

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Solution Overview

Problem

Existing liquid flow-path members, particularly those used in inkjet printers, are not adaptable for ultraviolet light-curing type liquids when the second member is light-transmissive and also transmissive of ultraviolet light, leading to insufficient robustness and inspection challenges.

Innovation Solution

A manufacturing method for a liquid flow-path member where the first member blocks ultraviolet light and absorbs laser light, and the second member blocks ultraviolet light while transmitting laser and visible light, allowing for laser welding to create a robust flow path using thermoplastic polyimide resin or similar materials, enabling the use of ultraviolet light-curing inks and facilitating inspection through visible light transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the second member is made light-transmissive to increase thickness and improve flow path robustness, then the mechanical strength is improved, but the member becomes incompatible with ultraviolet light-curing type liquids when the material also transmits ultraviolet light

Engineering Contradiction:

Improveflow path robustnessVSAvoidcompatibility with ultraviolet light-curing type liquids

Core Design Contradiction:

StrengthVSAdaptability or versatility

Solution Approach 1:

The second member is designed with different optical properties for different wavelength ranges: it transmits laser light (visible spectrum) for welding and inspection purposes, but blocks ultraviolet light to prevent curing of ultraviolet light-curing type liquids during storage and transport. This selective transmission/blocking capability resolves the contradiction by providing both robustness and compatibility.

Inventive Principle:

Principle #3Local quality

2Adaptability or versatility

If the second member is made transmissive of ultraviolet light to allow ultraviolet light-curing type liquids to pass through, then the liquid flow is enabled, but the member cannot be effectively welded using laser light

Engineering Contradiction:

Improvecompatibility with ultraviolet light-curing type liquidsVSAvoidweldability using laser light

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

Inventive Principle:

Principle #3Local quality

3Strength

If the second member is made thick to improve flow path robustness, then the mechanical strength is improved, but the inspection of joint surface quality becomes more difficult

Engineering Contradiction:

Improveflow path robustnessVSAvoidjoint surface inspection difficulty

Core Design Contradiction:

StrengthVSDifficulty of detecting and measuring

Solution Approach 1:

The second member is designed to be transparent to visible light (laser light wavelength), allowing optical inspection of the joint surface quality through the member thickness. This transparency property enables effective detection and measurement of joint quality even in thick members, resolving the contradiction between robustness and inspectability.

Inventive Principle:

Principle #32Color changes

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 method enhances the robustness of the liquid flow-path member by allowing thicker second substrates and enables the use of ultraviolet light-curing inks, while allowing for easier inspection of the joint surface quality, resulting in improved mechanical strength and operational efficiency.

Implementation Method 1

the first member is formed of a material that blocks ultraviolet light and absorbs laser light

Methodology Applied

Scientific EffectLaser light absorption: Absorption (EM radiation)

Implementation Method 2

the second member is formed of a material that blocks ultraviolet light and transmits laser light and visible light

Methodology Applied

Scientific EffectLaser light transmission: Light

Implementation Method 3

the first member is formed of a material that blocks ultraviolet light

Methodology Applied

Scientific EffectUltraviolet light blocking: Absorption (EM radiation)

Implementation Method 4

the second member is formed of a material that blocks ultraviolet light

Methodology Applied

Scientific EffectUltraviolet light blocking: Absorption (EM radiation)

Data Source

PatentUS11312152B2Liquid flow-path member, and manufacturing method for liquid flow-path member

Publication Date: 2022.04.26 SEIKO EPSON CORP

AI summary

A manufacturing method for a liquid flow-path member including a flow path between a first substrate and a second substrate layered together, the method including a welding step for welding the first substrate and the second substrate together, in which in the method, the first substrate is formed of a material that blocks ultraviolet light and absorbs laser light, the second substrate is formed of a material that blocks ultraviolet light and transmits laser light, and in which the welding step includes melting, with laser light passing through the second member, a joint surface where the first member and the second member are joined to weld the first member and the second member together.