PZT Micro-Actuator Segmentation for Disk Drive HGA Shock Resistance
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Solution Overview
Problem
Conventional PZT micro-actuators for disk drive head gimbal assemblies suffer from weak structural connections, high manufacturing costs due to complex electrode layer connections, and poor shock performance, leading to increased waste and instability in positional control.
Innovation Solution
The use of separate PZT elements with physically connected but electrically isolated electrode-piezoelectric combination layers, allowing for individual defect detection and reduced manufacturing costs, along with a strengthened suspension structure featuring side strength beams and flexible arms to enhance shock performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If two PZT elements are mechanically connected to form a single micro-actuator, then the actuator can provide bidirectional displacement control, but the structural connection becomes weak and prone to deformation or breakage
Solution Approach 1:
The patent divides the PZT micro-actuator into two separate PZT elements that are independently mounted on the suspension, eliminating the need for mechanical connection between them. Each element can be independently controlled to achieve bidirectional displacement, while avoiding the weak structural connection problem.
Solution Approach 2:
The patent introduces a common electrode layer as an intermediary that provides both mechanical support and electrical connection for the two separate PZT elements. This common layer acts as a mediator that eliminates the need for direct mechanical connection between the PZT elements while maintaining structural integrity.
2Reliability
If corresponding electrode layers of multiple PZT elements are connected by sputtering process, then electrical connections are established, but the manufacturing process becomes complex and costly
Solution Approach 1:
The patent merges the electrical connection function into the common electrode layer that is already part of the suspension structure. The common electrode layer serves dual purposes: providing mechanical support and establishing electrical connections, thereby simplifying the manufacturing process and reducing costs.
Solution Approach 2:
The common electrode layer is designed to perform multiple functions: it serves as a structural support element, an electrical connection point for both PZT elements, and a grounding reference. This multi-functionality reduces the need for additional components and manufacturing steps.
3Ease of operation
If two PZT elements are mechanically connected, then they function as a single actuator unit, but defect detection becomes difficult and waste increases when one element is defective
Solution Approach 1:
The patent segments the PZT actuator system into two independently mounted elements, each with separate electrical connections to the common electrode layer. This segmentation enables independent testing and defect detection of each element, allowing replacement of only the defective element rather than the entire actuator assembly.
Solution Approach 2:
The patent enables preliminary defect detection of individual PZT elements before final assembly, by providing separate electrical access to each element through the common electrode layer. This allows quality control measures to identify and replace defective elements early in the manufacturing process, reducing waste.
4Speed
If the suspension structure is lightweight and flexible, then the HGA can achieve good dynamic performance, but the shock performance and structural stability deteriorate
Solution Approach 1:
The patent employs a composite suspension structure that combines flexible regions (for dynamic performance) with strengthened regions containing the common electrode layer and PZT mounting areas (for shock resistance). This composite design allows different parts of the suspension to optimize for their specific functions.
Solution Approach 2:
The common electrode layer and strengthened suspension regions act as pre-designed structural reinforcements that provide shock resistance before shocks occur. These strengthened regions are strategically positioned to absorb and distribute impact forces, protecting the PZT elements and other sensitive components.
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 design improves the structural integrity and reduces waste by enabling individual PZT element defect detection, lowers manufacturing costs, and enhances shock performance and positional control stability, thereby increasing the reliability and efficiency of disk drive operations.
Implementation Method 1
The PZT micro-actuator comprises two thin film PZT elements which are connected with each other. When a voltage is input to the two thin film PZT elements, one of the PZT elements may contract while the other may expand, thus making the slider support and the slider rotate against the dimple
Implementation Method 2
The at least two electrode-piezoelectric combination layers are physically connected with but electrically isolated from each other
Data Source
AI summary
A PZT micro-actuator for a head gimbal assembly includes a pair of separate PZT elements and each PZT element has a body and a plurality of electrical pads. The body has at least two electrode-piezoelectric combination layers laminated together. The at least two electrode-piezoelectric combination layers are physically connected with but electrically isolated from each other. Each electrode-piezoelectric combination layer has at least two of the electrical pads thereon. The electrical pads extend out from the body of the corresponding PZT element. All the electrical pads of each PZT element are offset a predetermined distance therebetween to be electrically isolated. The present invention also discloses a head gimbal assembly (HGA) with the PZT micro-actuator, an assembling method for the head gimbal assembly and a disk drive unit having such HGA.