Piezo Stack Ceramic Plastic Passivation
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Solution Overview
Problem
Existing piezo stacks face issues with electrical flashovers and short circuits due to mechanical damage, contamination, and inadequate passivation, particularly at the edges, which can lead to operational failures and reduced durability.
Innovation Solution
A fully active piezo stack with ceramic passivation on two opposite side surfaces and plastic passivation on the other two surfaces, ensuring comprehensive coverage and enhanced protection against electrical flashovers, combined with a simplified manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional plastic passivation is used on piezo stack surfaces, then ease of manufacture is improved, but reliability deteriorates due to electrical flashovers and short circuits from mechanical damage and contamination
Solution Approach 1:
The patent applies a composite passivation structure combining ceramic material applied to side surfaces and plastic material applied to top and bottom surfaces. The ceramic provides superior electrical insulation and mechanical durability to prevent flashovers, while the plastic simplifies manufacturing for horizontal surfaces. This composite approach resolves the contradiction by selecting materials optimized for their specific functional requirements on different surfaces.
Solution Approach 2:
The patent implements different passivation materials on different surfaces of the piezo stack based on local requirements. Ceramic passivation is applied to vertical side surfaces where electrical insulation and contamination resistance are critical, while plastic passivation is used on horizontal top and bottom surfaces where manufacturing ease and electrode access are priorities. This localized material selection optimizes both reliability and manufacturability.
2Reliability
If ceramic passivation is applied to all surfaces of the piezo stack, then reliability and resistance to external influences are improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent applies ceramic passivation selectively only to the vertical side surfaces of the piezo stack where electrical insulation and contamination resistance are most critical for preventing flashovers. The horizontal top and bottom surfaces use simpler plastic passivation. This localized application of ceramic material provides maximum protection where needed while avoiding the unnecessary complexity and manufacturing difficulty of applying ceramic to all surfaces.
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 effectively prevents electrical flashovers and short circuits, improves mechanical and temperature stability, and simplifies the manufacturing process by using ceramic passivation, which is more robust and resistant to external influences than traditional plastic materials.
Implementation Method 1
the effect is exploited that they become charged under mechanical pressure or tension and, on the other hand, expand along the main axis of the ceramic layer when an electrical voltage is applied
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to a fully active piezo stack (10) having lateral surfaces (1, 2, 3, 4), wherein a passivation layer (9a, 9b) made of ceramic is arranged on two opposite lateral surfaces (1, 2) over the respective width, and a passivation layer (6a, 6b) comprising plastic is arranged on the other two opposite lateral surfaces (3, 4), and thus all lateral surfaces (1, 2, 3, 4) are provided with a passivation layer (9a, 9b, 6a, 6b) over the respective width.