Piezoelectric Liquid-Jet Head Electrode Design for Voltage Stability
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Solution Overview
Problem
Ink-jet recording heads with piezoelectric elements face issues of unstable ink ejecting properties due to voltage drops and manufacturing errors, which affect the rigidity and resistance values of the common electrode and lead electrode, leading to variations in ink ejecting performance.
Innovation Solution
A liquid-jet head design featuring a passage-forming substrate with piezoelectric elements having a lower common electrode continuously provided across pressure generating chambers, with lead electrodes drawn out from the upper and lower electrodes, and a connection portion positioned outside the pressure generating chambers to prevent voltage drops and manufacturing errors, ensuring stable ink ejecting properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the common electrode and common lead electrode are formed as different members using deposition technology, then the manufacturing process is flexible, but manufacturing errors occur causing the common lead electrode to protrude into the pressure generating chamber region and enhance vibration plate rigidity, leading to variation in ink ejecting property
Solution Approach 1:
The patent merges the common electrode and common lead electrode into a single continuous electrode structure formed by one lithography pattern. This eliminates the interface between two separately formed electrodes, preventing protrusion errors into the pressure generating chamber region while maintaining manufacturing flexibility through standardized deposition processes.
Solution Approach 2:
The single continuous electrode is segmented into functional regions (common electrode region and common lead electrode region) through lithography patterning, allowing distinct functional zones without requiring separate deposition steps. This segmentation within a single formation process prevents manufacturing errors at electrode interfaces.
2Reliability
If the thickness of the common electrode is increased to prevent voltage drop, then the resistance value is reduced, but the amount of deformation of the vibration plate is reduced, affecting ink ejecting property
Solution Approach 1:
The electrode system is segmented into a thin common electrode (maintaining vibration plate deformation capability) and a separate common lead electrode (providing low resistance current path). This segmentation allows the common electrode to remain thin for proper vibration while the lead electrode compensates for resistance, preventing voltage drop during simultaneous piezoelectric element driving.
Solution Approach 2:
The common lead electrode acts as an intermediary current path that bypasses the thin common electrode. By providing a low-resistance parallel path for current flow, it mediates between the conflicting requirements of thin electrode structure (for vibration) and low resistance (for voltage stability).
3Strength
If the thickness of the common electrode is reduced to maintain vibration plate deformation, then the resistance value is increased, causing voltage drop when multiple piezoelectric elements are driven simultaneously
Solution Approach 1:
The electrode system is segmented into a thin common electrode (maintaining vibration plate deformation capability) and a separate common lead electrode (providing low resistance current path). This segmentation allows the common electrode to remain thin for proper vibration while the lead electrode compensates for resistance, preventing voltage drop during simultaneous piezoelectric element driving.
Solution Approach 2:
The common electrode and common lead electrode are merged into a single continuous conductive structure formed by one lithography pattern. This integration ensures low resistance current path while maintaining the thin profile needed for vibration plate deformation, as the lead portion extends outside the pressure generating chamber region where it provides electrical connection without interfering with vibration.
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 effectively prevents voltage drops and manufacturing errors, resulting in a stable and consistent ink ejecting performance by reducing resistance values and maintaining the rigidity of the vibration plate.
Implementation Method 1
a part of pressure generating chambers communicating with nozzle orifices is formed of a vibration plate, this vibration plate is deformed by piezoelectric elements, and ink in the pressure generating chambers is pressurized to eject ink droplets from the nozzle orifices
Data Source
AI summary
A liquid-jet head includes a passage-forming substrate. A plurality of pressure generating chambers communicate with nozzles. Piezoelectric elements each include a lower electrode, a piezoelectric layer and an upper electrode. Leads for the upper and lower electrodes are drawn out. In the liquid-jet head, the lower electrode is a common electrode continuously provided in the region facing the pressure generating chambers. At least an end on one side of the lower electrode in a direction perpendicular to an arrangement direction of the pressure generating chambers is positioned in the region facing the pressure generating chambers. The lead electrode for the lower electrode is provided outside of a region corresponding to a space between the pressure generating chambers. The lead electrode for the lower electrode is connected through a common lead portion extended from the lower electrode.