Vibration Plate with Local Elastic Modulus for Crack Suppression
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Solution Overview
Problem
The existing liquid discharge heads face issues with crack formation in the vibration plate, leading to reduced discharge performance and mechanical stress, as the increased hardness or thickness of the vibration plate makes it difficult to deform, thereby affecting the discharge amount and speed.
Innovation Solution
A liquid discharge head design featuring a vibration plate with distinct areas of different elastic moduli, where a third layer with a lower elastic modulus is strategically positioned to reduce stress concentrations and prevent cracking, while maintaining necessary deformation for efficient discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the hardness of the vibration plate is increased to suppress crack occurrence, then the reliability is improved, but the vibration plate becomes difficult to deform and discharge performance is reduced
Solution Approach 1:
The vibration plate is designed with a two-layer structure where the first layer (contacting piezoelectric element) has higher hardness to suppress cracks, while the second layer has lower hardness to maintain deformability. This local differentiation of material properties resolves the contradiction between crack suppression and discharge performance.
Solution Approach 2:
The vibration plate uses a composite structure of two different materials: a harder first layer material and a softer second layer material. This composite approach allows the plate to simultaneously achieve crack resistance from the harder layer and flexible deformation from the softer layer, resolving the performance contradiction.
2Reliability
If the film thickness of the vibration plate is thickened to suppress crack occurrence, then the reliability is improved, but the vibration plate becomes difficult to deform and discharge performance is reduced
Solution Approach 1:
Instead of uniformly increasing thickness, the invention uses a two-layer structure where the first layer provides crack suppression and the second layer maintains deformability. This local differentiation allows crack suppression without sacrificing discharge performance.
Solution Approach 2:
The composite two-layer structure replaces uniform thickness increase with differentiated material layers, achieving crack suppression through the harder first layer while maintaining flexibility through the softer second layer.
3Reliability
If the elastic modulus of the vibration plate is increased to suppress crack occurrence, then the reliability is improved, but the vibration plate becomes difficult to deform and discharge performance is reduced
Solution Approach 1:
The vibration plate employs spatially varying elastic modulus through its two-layer structure: the first layer has higher elastic modulus for crack suppression, while the second layer has lower elastic modulus for maintaining deformability and discharge performance.
Solution Approach 2:
The composite structure with materials of different elastic moduli allows the vibration plate to simultaneously achieve high crack resistance (from the higher modulus first layer) and sufficient deformability (from the lower modulus second layer).
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 suppresses crack formation and maintains discharge performance by distributing mechanical stress, ensuring stable and precise liquid discharge over time.
Implementation Method 1
a vibration plate constituting a wall surface of a pressure chamber is vibrated by a piezoelectric element to discharge a liquid such as an ink filled in the pressure chamber from a nozzle
Implementation Method 2
a sixth step of forming a second layer containing zirconium oxide by thermally oxidizing the zirconium-containing layer
Data Source
AI summary
A liquid discharge head includes a first substrate in which a nozzle is formed, a second substrate disposed above the first substrate, an energy generation element that generates energy for discharging a liquid by a drive signal being applied, and a vibration plate that vibrates by the energy generated by the energy generation element and that is stacked on the second substrate, in which the vibration plate has a first area and a second area positioned at a position different from the first area and having a lower elastic modulus than an elastic modulus of the first area.