Liquid Ejecting Head Common Electrode Thickness Gradient
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Solution Overview
Problem
Ink jet recording heads face challenges in achieving high piezoelectric element density while maintaining displacement magnitude and preventing voltage drops, leading to uneven discharge properties due to increased electric resistance.
Innovation Solution
A liquid ejecting head design featuring piezoelectric actuators with a common electrode divided by slits and a base section, where the film thickness gradually increases from thin to thick sections, reducing electric resistance and stress concentration, thereby improving displacement magnitude and endurance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If piezoelectric element density is increased to improve printing quality, then printing quality is improved, but displacement magnitude deteriorates
Solution Approach 1:
The common electrode is designed with non-uniform thickness: thin film sections at the individual electrode sides and a thick film section at the base section. This local variation in electrode thickness allows different regions to serve different functions - thin sections reduce stress on piezoelectric elements for better displacement, while the thick base section provides mechanical support and electrical stability
2Length of moving object
If electrode thickness is reduced to maintain displacement magnitude, then displacement magnitude is maintained, but electric resistance rises and voltage drops
Solution Approach 1:
The common electrode implements local quality variation with thin film sections where displacement is needed and a thick film section at the base where electrical stability is critical. This resolves the contradiction by having the thick base section provide low electrical resistance and voltage stability, while thin film sections maintain displacement magnitude
3Ease of manufacture
If electrode structure is simplified for ease of manufacture, then ease of manufacture is improved, but stress concentration and cracking increase
Solution Approach 1:
The individual sections of the common electrode are designed with curved corners instead of sharp angles. This curvature eliminates stress concentration points that would lead to cracking, thereby improving endurance while maintaining ease of manufacture through a relatively simple electrode structure
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 design enhances displacement properties and endurance by suppressing voltage drops and stress concentration, resulting in uniform ink discharge and improved printing quality.
Implementation Method 1
piezoelectric actuators that eject liquid droplets through the nozzle openings by generating changes in pressure in the pressure chambers. The piezoelectric actuators have individual electrodes provided so as to correspond to the pressure chambers, a common electrode shared by the piezoelectric actuators, and a piezoelectric layer that is formed between the common electrode and the individual electrodes
Data Source
AI summary
A common electrode includes a plurality of individual sections arranged so as to correspond to pressure chambers that are divided by a plurality of slits, and a base section that joins one end of the individual sections. The individual sections on a base section side gradually widen in plain view. The common electrode has thin film sections at the individual sections and a thick film section at the base section, and the film thickness gradually increases from the thin film sections towards the thick film section in a region between the thin film sections and the thick film section.