Liquid Discharge Head Substrate Crack Prevention

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

The existing methods for manufacturing liquid discharge heads are prone to crack formation in the end covering portion of the cover layer during the etching process, which can lead to warpage and quality issues in the flow path forming member due to internal stress and inadequate adhesion near steps in the sacrificial layer.

Innovation Solution

A method involving a sacrificial layer on the front surface of the base with a cover layer and a resin layer that covers the end covering portion, where the resin layer has an opening smaller than the sacrificial layer, providing reinforcement during etching from the back surface to prevent crack formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a cover layer is provided to cover the sacrificial layer during etching, then the sacrificial layer is protected, but cracks may form in the end covering portion due to warpage and internal stress

Engineering Contradiction:

Improveprotection of sacrificial layerVSAvoidcrack resistance of cover layer

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The cover layer is divided into two distinct parts: a first cover layer that covers the sacrificial layer during etching, and a second cover layer (resin layer) that covers the end covering portion. This segmentation allows each layer to perform its specific function without the structural weaknesses that would occur in a single unified layer.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The resin layer acts as an intermediary protective element that reinforces the end covering portion of the cover layer. It provides additional mechanical support and prevents crack formation in regions where the cover layer is most vulnerable to warpage and internal stress during the etching process.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Manufacturing precision

If etching is performed from the back surface of the base, then the supply port is formed with high dimensional accuracy, but warpage occurs due to internal stress

Engineering Contradiction:

Improvedimensional accuracy of supply portVSAvoidwarpage of base

Core Design Contradiction:

Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

The resin layer is applied in advance to the end covering portion of the cover layer before the etching process begins. This pre-reinforcement cushions the structure against the warpage and internal stress that will occur during back-surface etching, allowing high dimensional accuracy to be achieved without compromising structural stability.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Adaptability or versatility

If the end covering portion has reduced film thickness to cover the step, then it provides flexibility, but adhesion becomes inadequate and cracks form

Engineering Contradiction:

Improvecoverage of step structureVSAvoidadhesion of cover layer

Core Design Contradiction:

Adaptability or versatilityVSStrength

Solution Approach 1:

The end covering portion is reinforced by combining the original cover layer material with a resin layer material. This composite structure maintains the ability to conform to the step structure while providing enhanced adhesion and mechanical strength, preventing crack formation in the thinned region.

Inventive Principle:

Principle #40Composite materials

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 effectively suppresses crack formation in the end covering portion, ensuring the integrity of the flow path forming member and maintaining the quality of the liquid discharge head by reinforcing the cover layer with a resin layer, thus preventing warpage and etchant-induced damage.

Implementation Method 1

providing a resin layer for covering the end covering portion... in a state in which the end covering portion is covered with the resin layer

Methodology Applied

Scientific EffectPhysical reinforcement:

Implementation Method 2

removing the sacrificial layer by etching the base from a back surface of the base

Methodology Applied

Scientific EffectEtching:

Data Source

PatentUS10730299B2Method for manufacturing liquid discharge head, liquid discharge head, and method for manufacturing liquid discharge head substrate

Publication Date: 2020.08.04 CANON KK

AI summary

There is provided a method for manufacturing a liquid discharge head including a liquid discharge head substrate and a flow path forming member, the liquid discharge head substrate having a base, a pressure generation portion provided at a front surface of the base to generate pressure for discharging a liquid, and a supply port for supplying the liquid to the pressure generation portion, and the flow path forming member forming a flow path for feeding the liquid supplied from the supply port to the pressure generation portion. The method includes removing a sacrificial layer by etching the base from a back surface of the base, in a state in which an end covering portion of a cover layer for covering the sacrificial layer is covered with the resin layer. The method suppresses formation of a crack in the end covering portion that covers the end portion of the sacrificial layer.