Piezoelectric Component with Predetermined Breaking Layer
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Solution Overview
Problem
Piezoelectric components, such as actuators, face reliability issues due to cracks that can lead to short circuits when electrode layers of different polarity are bridged, particularly during mechanical stresses or thermal processes, which can be exacerbated by foreign substance penetration through porous areas.
Innovation Solution
Incorporating predetermined breaking layers with reduced mechanical strength and higher porosity between electrode layers of different polarity to control crack formation and propagation, ensuring cracks occur within these layers and do not bridge electrode layers, while maintaining a reduced electric field to minimize foreign substance ingress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If predetermined breaking layers with higher porosity are used to control crack propagation, then crack guidance capability is improved, but susceptibility to foreign substance penetration increases
Solution Approach 1:
The patent applies local quality by creating predetermined breaking layers with locally modified properties (higher porosity, lower mechanical strength) at specific positions between electrode layers, while maintaining different polarity orientations in different regions to control crack propagation paths locally without uniform modification throughout the entire component
Solution Approach 2:
The predetermined breaking layers act as intermediary structures that mediate between the conflicting requirements of crack control and foreign substance resistance. These layers provide controlled crack paths while their strategic placement between oppositely polarized electrode layers creates electrical barriers that indirectly protect against foreign substance effects
2Reliability
If predetermined breaking layers are placed between electrode layers of different polarity, then crack path control is improved, but electric field strength is reduced in functional areas
Solution Approach 1:
The patent segments the stack into different regions: functional regions with standard electrode spacing for energy conversion, and protected regions with increased spacing containing predetermined breaking layers for reliability. This segmentation allows optimization of different areas for different purposes without compromising overall performance
Solution Approach 2:
The patent changes the geometric parameter (distance d2) between electrode layers in specific regions where predetermined breaking layers are placed, increasing the spacing to reduce electric field strength and foreign substance penetration risk, while maintaining standard spacing (d1) in functional regions for optimal energy conversion
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 approach reduces the risk of component failure by containing cracks and foreign substance penetration, enhancing reliability and maintaining performance with reduced need for complex encapsulations.
Implementation Method 1
When a voltage is applied to the electrode layers, the piezoelectric layers expand in the stacking direction, so that a stroke of the actuator is generated
Implementation Method 2
The predetermined breaking layers are preferably formed in such a way that a crack occurs at a point in the component specified by the predetermined breaking layer and only runs in one plane parallel to the planes of the electrode layers
Implementation Method 3
Before sintering, the binder is removed by a decarburization process, leaving pores in the layer where the binder was
Implementation Method 4
The foils are stacked, pressed and sintered together, resulting in a monolithic sintered body
Data Source
Figure 1~2B
Figure 3A~3B
Figure 4
AI summary
The invention relates to a piezoelectric component (1) comprising at least one planned fracture layer (5) for generating and guiding cracks (23) in the component (1) in a controlled manner. The planned fracture layer (5) is disposed between two electrode layers (3, 4, 31, 41) adjacent to each other in the direction of the stack. The distance d2 of said two electrode layers (3, 4, 31, 41) is greater than the distance d1 of two adjacent electrode layers (3, 4) between which no planned fracture layer (5) is provided.