Piezoelectric Layer Surface Gradient for Inkjet Heads
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Solution Overview
Problem
Existing piezoelectric devices for inkjet printing heads face challenges in forming a structure-gradient region (SGR) along the surface direction of the piezoelectric layer, which is crucial for high piezoelectric characteristics, due to difficulties in precisely varying the components of the precursor solution.
Innovation Solution
A piezoelectric device with a composite oxide of Perovskite structure containing potassium, sodium, niobium, and manganese, featuring a 3 μm×3 μm region with distinct atomic concentration ratios of potassium to sodium, and crystal grains of 1 μm or less, forming an SGR along the surface direction through chemical solution deposition and precise layering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the components of the precursor solution are precisely varied to form an SGR along the surface direction, then high piezoelectric characteristics are achieved, but manufacturing difficulty increases due to the complexity of precise component variation
Solution Approach 1:
The piezoelectric layer is divided into multiple sub-layers, each with controlled thickness and specific composition ratios. By segmenting the layer structure and controlling the thickness of each sub-layer, the patent achieves formation of an SGR along the surface direction without requiring complex continuous composition variation, thus improving manufacturability while maintaining high piezoelectric characteristics
Solution Approach 2:
Different regions of the piezoelectric layer are given different local compositions (varying K/Na ratios) to create the SGR structure. The patent implements local quality by controlling the composition of each sub-layer differently, creating regions with distinct atomic concentration ratios that form the desired gradient structure along the surface direction
2Reliability
If a structure-gradient region is formed in the laminate direction by varying precursor solution components layer by layer, then high piezoelectric characteristics are achieved, but it remains difficult to form an SGR along the surface direction due to precision requirements
Solution Approach 1:
The patent segments the piezoelectric layer into multiple sub-layers (first, second, third, etc.) with controlled thicknesses. By varying the composition and thickness of each sub-layer in a systematic sequence, the SGR along the surface direction is formed through cumulative thickness control rather than requiring ultra-precise continuous composition variation, thereby reducing manufacturing precision requirements
Solution Approach 2:
Instead of varying composition continuously in the surface plane (two-dimensional variation), the patent uses the thickness dimension (third dimension) to control the formation of the SGR. By controlling sub-layer thicknesses systematically, the patent transforms a two-dimensional composition control problem into a one-dimensional thickness control problem, reducing manufacturing precision requirements
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 enables the formation of a surface SGR with high piezoelectric characteristics, enhancing the device's performance by creating a larger lattice constant difference and reducing leak current.
Implementation Method 1
a piezoelectric device that includes: a first electrode provided above a substrate; a piezoelectric layer provided above the first electrode; and a second electrode provided above the piezoelectric layer
Data Source
AI summary
A piezoelectric device includes: a first electrode provided above a substrate; a piezoelectric layer provided above the first electrode; and a second electrode provided above the piezoelectric layer. The piezoelectric layer includes a plurality of layers that includes a composite oxide of a Perovskite structure containing potassium, sodium, and niobium. The piezoelectric layer has a first region and a second region in a 3 μm×3 μm region of a plane perpendicular to a thickness direction of the piezoelectric layer. The first region is a region in which the ratio of an atomic concentration (atm %) of potassium with respect to the sum of the atomic concentration (atm %) of potassium and an atomic concentration (atm %) of sodium is 0.30 to 0.45, and the second region is a region in which the ratio is 0.55 to 0.75.