Liquid Ejecting Head Auxiliary Wiring Reduces Common Electrode Resistance
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Solution Overview
Problem
Existing liquid ejecting heads face challenges in reducing the resistance of common electrodes while maintaining the thickness of the head, as increasing the height of the common electrode is limited by the recess height and making the protection portion thicker increases the head's thickness.
Innovation Solution
A liquid ejecting head is designed with a piezoelectric element that includes a common electrode with an auxiliary wiring line electrically coupled to the common wiring line, reducing the resistance of the common electrode without increasing the head's thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the height of the common electrode is increased to reduce resistance, then the resistance is reduced, but the height can only be increased to a height range of the recess, so the resistance may not be sufficiently reduced
Solution Approach 1:
The patent introduces an auxiliary electrode that extends in the thickness direction (Z-direction) beyond the common electrode, creating a new dimension for reducing resistance. This auxiliary electrode is coupled to the common electrode through a through-hole, allowing current to flow through an additional path without increasing the planar height of the common electrode within the recess.
Solution Approach 2:
The auxiliary electrode acts as an intermediary component that bridges the common electrode and the external wiring. By introducing this intermediate element with a through-hole connection, the patent creates an additional current pathway that reduces the overall resistance without requiring the common electrode itself to extend further in the recess height direction.
2Reliability
If the protection portion itself is made thicker and the recess is made thicker to reduce resistance, then the resistance is reduced, but this poses an issue of increasing a thickness of the liquid ejecting head
Solution Approach 1:
The patent segments the electrode structure into a common electrode and a separate auxiliary electrode. The auxiliary electrode is positioned adjacent to the common electrode and connected through a through-hole, creating distinct functional zones. This segmentation allows the auxiliary electrode to provide additional current path without requiring the common electrode or protection portion to be thicker.
Solution Approach 2:
Instead of increasing the thickness of the protection portion or recess in the Z-direction, the patent utilizes the auxiliary electrode to extend the current path in a different spatial arrangement. The auxiliary electrode with its through-hole connection creates a parallel current pathway that reduces resistance without increasing the overall thickness of the liquid ejecting head.
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 solution effectively reduces the resistance of the common electrode, improving the printing quality by minimizing voltage fluctuations and maintaining the thickness of the liquid ejecting head.
Implementation Method 1
a piezoelectric element that includes a piezoelectric body, an individual electrode individually provided for each of the plurality of pressure chambers, and a common electrode provided in common to the plurality of pressure chambers
Data Source
AI summary
A liquid ejecting head includes: a nozzle substrate provided with a nozzle for ejecting a liquid; a pressure chamber substrate provided with a plurality of pressure chambers for applying pressure to the liquid; a piezoelectric element including a piezoelectric body, an individual electrode individually provided for each of the plurality of pressure chambers, and a common electrode provided in common to the plurality of pressure chambers; and a wiring substrate provided with an individual wiring line for applying a voltage to the individual electrode, a common wiring line for applying a voltage to the common electrode, and an auxiliary wiring line that is electrically coupled to the common wiring line to reduce resistance of the common electrode.