Inkjet Printhead Metal Conductor Inclined Segment Removal

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Solution Overview

Problem

Inkjet printheads face issues with the reflection of electromagnetic radiation during the formation of firing chambers, leading to incomplete removal of photoimageable material over resistors due to the presence of inclined metal conductor segments, which affects the integrity of the cavitation barrier and the strength of upper layers.

Innovation Solution

The removal of inclined segments of the metal conductor from the inclined surfaces of the dielectric regions between resistors prevents radiation reflections, allowing for the proper exposure and removal of photoimageable material, thereby ensuring the formation of robust cavitation barriers and preventing excess crosslinked material from forming over the resistors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If an inclined segment of metal conductor is left over the dielectric region between resistors, then the cavitation barrier has greater strength and integrity, but electromagnetic radiation reflects off the inclined surface causing incomplete removal of photoimageable material over the resistors

Engineering Contradiction:
Improvecavitation barrier strengthVSAvoidphotoimageable material removal completeness
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The inclined segment of metal conductor is selectively removed from the dielectric region between resistors. This extraction eliminates the harmful radiation reflection surface while preserving the metal conductor segments over the resistors that form the cavitation barrier, thus resolving the contradiction between barrier strength and manufacturing precision

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The metal conductor structure is made non-uniform by removing inclined segments only from specific locations (dielectric regions between resistors) while retaining metal conductor over the resistors themselves. This local differentiation allows the cavitation barrier to maintain strength where needed while eliminating radiation reflection problems in specific areas

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If the inclined segment of metal conductor is removed from the dielectric region, then radiation reflections are prevented and photoimageable material is properly removed, but the cavitation barrier strength and integrity are reduced

Engineering Contradiction:
Improvephotoimageable material removal completenessVSAvoidcavitation barrier strength
Core Design Contradiction:
Manufacturing precisionVSStrength

Solution Approach 1:

Instead of removing the entire metal conductor structure, only the harmful inclined segments over the dielectric regions are extracted. This selective removal maintains the essential cavitation barrier function while eliminating the radiation reflection problem

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The metal conductor structure is differentiated locally: segments over resistors are retained to provide cavitation barrier strength, while segments over dielectric regions are removed to prevent radiation reflection. This local quality variation resolves the contradiction

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If photoimageable material over resistors is exposed to radiation through reflection from the inclined metal surface, then the material crosslinks and cannot be removed by solvent, but removing the inclined segment prevents this crosslinking

Engineering Contradiction:
Improvephotoimageable material removal easeVSAvoidfiring chamber formation reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The inclined metal segment that causes harmful radiation reflection is extracted from the structure. This eliminates the source of unintended photoimageable material crosslinking, allowing solvent removal to proceed effectively and improving manufacturing ease

Inventive Principle:
Principle #2Taking out (Extraction)

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 enhances the integrity and strength of the cavitation barriers, ensuring effective ink ejection and reducing the formation of excess crosslinked material, which can impede the formation of firing chambers, thereby improving the overall performance of the printhead.

Implementation Method 1

the reflection of electromagnetic radiation during the formation of firing chambers, leading to incomplete removal of photoimageable material over resistors due to the presence of inclined metal conductor segments

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

incomplete removal of photoimageable material over resistors due to the presence of inclined metal conductor segments, which affects the integrity of the cavitation barrier

Methodology Applied
Scientific EffectPhotopolymerisation: Photopolymerisation

Data Source

PatentEP3237214B1Removing an inclined segment of a metal conductor while forming printheads
Publication Date: 2021.06.02 HEWLETT PACKARD DEVELOPMENT COMPANY LP
  • EP3237214B1 patent drawingFigure 1A~1B
  • EP3237214B1 patent drawingFigure 1C~1D
  • EP3237214B1 patent drawingFigure 1E~1F

AI summary

An example of a method of forming a printhead includes forming first and second resistors over a first dielectric, forming a first portion of a second dielectric over the first and second resistors and a second portion of the second dielectric over an exposed inclined surface of the first dielectric in a region between the first and second resistors, forming a metal conductor over the first and second portions of the second dielectric, and removing an inclined segment of the metal conductor from an inclined surface of the second portion of the second dielectric to expose the inclined surface of the second portion of the second dielectric.