Liquid Discharge Head Substrate Layout for Crack Containment
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Solution Overview
Problem
Existing liquid discharge heads are prone to defects such as cracking and deformation at the channel substrate periphery, leading to liquid leakage and quality abnormalities due to defects extending inward.
Innovation Solution
Incorporating first and second recesses and flat portions on the channel substrate to prevent defects from extending inward, using silicon-based materials for rigidity and integrating piezoelectric elements for precise liquid discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple relief grooves are provided in the peripheral edge of the channel substrate to prevent liquid leakage from cracks, then liquid leakage prevention is improved, but the structural complexity and potential for defect extension increase
Solution Approach 1:
The channel substrate is segmented into distinct functional regions: a channel formation region containing the liquid channels, and a flat portion with zero curvature that separates the channel region from the peripheral edge. This segmentation prevents defect propagation from the periphery into the channel region while maintaining structural integrity.
Solution Approach 2:
The flat portion is designed with specific local properties (zero curvature, planar surface) that differ from the channel formation region. This local quality change creates a barrier that stops crack propagation while allowing the channel region to maintain its functional geometry for liquid flow.
2Strength
If the channel substrate periphery is reinforced to prevent cracking, then structural strength is improved, but defect extension into the channel region may still occur
Solution Approach 1:
The flat portion acts as an intermediary barrier between the peripheral edge and the channel formation region. It mediates the stress distribution and prevents crack propagation from the periphery into the channel region, while allowing both regions to maintain their respective structural requirements.
3Manufacturing precision
If the channel substrate curvature is reduced to prevent defect initiation, then manufacturing precision is improved, but the ability to contain existing defects is compromised
Solution Approach 1:
The flat portion is designed in advance as a defect containment barrier. By pre-establishing this planar region with zero curvature before any defects can propagate, the structure proactively prevents defect extension into the channel formation region, combining manufacturing precision with reliability.
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
Reduces the occurrence of quality abnormalities by containing defects at the substrate periphery, ensuring reliable and high-quality liquid discharge performance.
Implementation Method 1
integrating piezoelectric elements for precise liquid discharge
Data Source
AI summary
A liquid discharge head includes: a nozzle plate having multiple nozzles from each of which a liquid is to be discharged, the multiple nozzles arrayed in a longitudinal direction of the nozzle plate; a channel substrate on the nozzle plate in a lamination direction orthogonal to the longitudinal direction, the channel substrate including: multiple channels arrayed in the longitudinal direction in a channel region of the channel substrate, the multiple channels respectively communicating with the multiple nozzles; a first recess outside the channel region in the longitudinal direction; and a flat portion between the channel region and the first recess in the longitudinal direction.