Liquid Jet Head Chip Electrode Pad Formation Without Photolithography

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Solution Overview

Problem

The yield ratio of head chips in liquid jet recording devices decreases due to failures in the process of forming the actuator plate, particularly due to issues with photolithography methods used in manufacturing.

Innovation Solution

The method involves using laser processing and surface removal processing to form common and active electrode pads on the actuator plate, eliminating the need for photolithography and reducing debris-related failures, thereby increasing the yield ratio.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If photolithography method is used to form electrode pads on the actuator plate, then the manufacturing process can be completed, but the yield ratio decreases due to debris-related failures

Engineering Contradiction:
Improvemanufacturing process completionVSAvoidyield ratio
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent replaces the photolithography method (chemical/optical process) with a mechanical scraping method using a blade. The blade physically removes excess conductive material from the actuator plate surface to form electrode pads, eliminating the need for photolithography chemicals and reducing debris-related failures that occur with the chemical process

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the manufacturing approach from a chemical-based photolithography process to a mechanical-based scraping process. This parameter change in the manufacturing method fundamentally alters how electrode pads are formed, replacing complex chemical reactions and light exposure with simple mechanical material removal, thereby improving yield ratio

Inventive Principle:
Principle #35Parameter changes

2Extent of automation

If photolithography method is used for forming electrode pads, then the process can be automated, but manufacturing precision decreases due to process failures

Engineering Contradiction:
Improveprocess automationVSAvoidelectrode pad formation accuracy
Core Design Contradiction:
Extent of automationVSManufacturing precision

Solution Approach 1:

The patent replaces the automated photolithography system with a simpler mechanical scraping system. The blade is positioned to scrape excess conductive material at precise locations, forming electrode pads through direct mechanical action rather than through complex automated photolithography equipment, thereby improving manufacturing precision while maintaining automation

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 reliability of the actuator plate formation, increases the yield ratio of head chips, and improves the performance of liquid jet recording devices by reducing ink leakage and power consumption.

Implementation Method 1

laser processing

Methodology Applied
Scientific EffectLaser ablation: Laser Ablation

Implementation Method 2

surface removal processing

Methodology Applied
Scientific EffectAbrasion: Abrasion

Data Source

PatentEP3939790B1Method of manufacturing head chip and method of manufacturing liquid jet head
Publication Date: 2023.07.12 SII PRINTEK INC
  • EP3939790B1 patent drawingFigure 1
  • EP3939790B1 patent drawingFigure 2
  • EP3939790B1 patent drawingFigure 3

AI summary

There are provided a method of manufacturing a head chip capable of suppressing the occurrence of the failure in the process of forming the actuator plate to thereby increase the yield ratio, and a method of manufacturing a liquid jet head using the above method of manufacturing a head chip. The method of manufacturing a head chip (41) is a method of manufacturing a head chip (41) having an actuator plate (411) adapted to apply pressure to liquid so as to jet the liquid. Forming the actuator plate includes forming a plurality of grooves (C1d, C1e) on a surface of a piezoelectric substrate (411Z) having one end (411E1) and the other end (411E2) so as to extend from the one end side toward the other end side, forming a conductive film (F) on the surface of the piezoelectric substrate provided with the plurality of grooves, forming a laser processing area (LA) in the conductive film between the grooves adjacent to each other by performing laser processing from a start point (Ps) on the one end side of the piezoelectric substrate to an end point on the other end side, and forming a surface removal area in at least a part including the start point and the end point out of the surface of the piezoelectric substrate by performing surface removal processing in a direction crossing the direction in which the laser processing is performed.