Piezoelectric Electrode Slit Layout for Crack Detection
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Solution Overview
Problem
Current methods for detecting cracks in piezoelectric elements, used in disk drive suspensions, are inadequate, leading to potential failures in positioning accuracy and recording density in hard disk drives.
Innovation Solution
A piezoelectric element design featuring electrodes with slits that extend from the peripheral edge, where the end portions of the slits are separated from the edge, allowing for easier detection of cracks by measuring changes in capacitance using an inspection device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If piezoelectric elements are miniaturized to support higher recording density, then positioning accuracy is improved, but cracks occur more easily during manufacturing
Solution Approach 1:
The patent applies preliminary action by forming slits in the electrodes before the piezoelectric element is fully manufactured and inspected. These slits are pre-positioned at locations where cracks are most likely to occur during manufacturing and use. By preparing these detection features in advance, the patent enables subsequent crack detection through capacitance measurements without requiring additional manufacturing steps after assembly.
2Manufacturing precision
If piezoelectric elements are made smaller and thinner, then positioning accuracy is improved, but detection of cracks becomes more difficult
Solution Approach 1:
The patent uses capacitance as an intermediary parameter to detect cracks indirectly. Instead of attempting to directly visualize or physically inspect cracks in the miniaturized piezoelectric element, the patent measures changes in capacitance between electrodes that occur when cracks develop. This intermediary measurement approach allows crack detection in elements that are too small for direct inspection methods.
Solution Approach 2:
The patent replaces mechanical or visual inspection methods with an electrical field-based detection method. By using capacitance measurements, the patent substitutes direct mechanical probing or optical inspection with an electrical field interaction that can detect the presence of cracks through changes in electrical properties, making detection feasible for miniaturized components.
3Reliability
If inspection methods are improved to detect cracks, then reliability is improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies self-service by designing the electrode structure itself to provide the detection functionality. The slits are formed as integral parts of the electrodes during normal manufacturing, and the electrodes themselves serve as both functional components and detection elements. This eliminates the need for separate inspection devices or complex external testing apparatus, as the structure serves both its actuation function and its own inspection function.
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 enables accurate detection of cracks, improving the reliability of piezoelectric elements and maintaining high positioning accuracy and recording density in disk drives.
Implementation Method 1
a piezoelectric body having a first main surface and a second main surface located on a side opposite to the first main surface
Data Source
AI summary
According to one embodiment, a piezoelectric element includes a piezoelectric body having a first main surface and a second main surface located on a side opposite to the first main surface, a first electrode provided on the first main surface, and a second electrode provided on the second main surface. The first electrode includes a first peripheral edge and a first slit extending from the first peripheral edge. An end portion of the first slit is separated from the first peripheral edge.