Piezoelectric Printing Device Inner Electrode Layer
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Solution Overview
Problem
Piezoelectric printing devices face challenges in achieving high printing resolution and fast throughput due to the large size of drop ejectors required for useful drop volumes, and the need for individual electrical leads for each drop ejector, which complicates electrical interconnection and manufacturing.
Innovation Solution
A configuration where the electrodes are placed on the inner surface of the piezoelectric plate proximate to the pressure chamber, with signal lines and ground traces on the first electrode layer connected to corresponding pads on the substrate through solder joints, allowing for compact and efficient electrical interconnection and enabling high-resolution, high-throughput printing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If electrodes are placed on the outer surface of the piezoelectric plate, then electrical interconnection is simplified, but drop ejection efficiency is reduced and variability in drop volume increases
Solution Approach 1:
The patent inverts the conventional electrode placement by positioning electrodes on the inner surface of the piezoelectric plate rather than the outer surface. This inversion allows the piezoelectric element to directly deflect the pressure chamber wall, improving drop ejection efficiency while maintaining electrical connectivity through the piezoelectric material itself.
Solution Approach 2:
The patent transitions from two-dimensional electrode placement on the outer surface to three-dimensional integration within the piezoelectric structure. By embedding electrodes on the inner surface and using vias to connect them, the design utilizes the depth dimension of the piezoelectric plate to achieve both efficient drop ejection and electrical connectivity.
2Quantity of substance
If piezoelectric chamber wall area is increased to achieve useful drop volumes, then drop volume is sufficient, but drop ejector size becomes large
Solution Approach 1:
The patent changes the geometric parameters of the pressure chamber by increasing the depth-to-width ratio. By making the pressure chamber deeper rather than wider, the design achieves sufficient drop volume while keeping the overall footprint of the drop ejector small, enabling closer nozzle spacing for high-resolution printing.
3Ease of operation
If individual electrical leads are provided for each drop ejector, then independent control is achieved, but device complexity increases
Solution Approach 1:
The piezoelectric plate serves multiple functions: it acts as the structural element defining the pressure chamber, the actuator that deflects the chamber wall for drop ejection, and the electrical conduit that transmits voltage from the outer surface electrodes to the inner surface electrodes. This multi-functionality eliminates the need for separate electrical leads for each drop ejector.
Solution Approach 2:
The patent merges the electrical connection path with the mechanical structure by using the piezoelectric material itself as the electrical conduit. The continuous piezoelectric plate provides both structural integrity and electrical connectivity, combining what would traditionally be separate components into a unified 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
This configuration enhances drop ejection efficiency with reduced variability in drop volume and velocity, facilitates compact electrical connections, and allows for space-efficient arrangement of drop ejectors, enabling high-resolution and fast printing.
Implementation Method 1
a piezoelectric element that causes the wall to deflect into the ink-filled pressure chamber when a voltage pulse is applied, so that ink is forced through the nozzle
Implementation Method 2
signal lines and ground traces on the first electrode layer connected to corresponding pads on the substrate through solder joints
Data Source
AI summary
A piezoelectric printing device includes a piezoelectric plate and a substrate with at least one row of drop ejectors. Each drop ejector includes a pressure chamber on a first side of the substrate and a nozzle on a second side of the substrate. The piezoelectric plate is attached to the substrate by a bonding layer. A first electrode layer is disposed on a first surface of the piezoelectric plate that is proximate to the first side of the substrate. The first electrode layer includes signal lines and ground traces corresponding to each pressure chamber. A second electrode layer including signal input pads and ground return pads is disposed on the first side of the substrate. Signal lines and ground traces in the first electrode layer are electrically connected to signal input pads and ground return pad(s) respectively on the second electrode layer through solder joints.