Disk Drive Flexure Stiffness and Impedance via Local Quality
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Solution Overview
Problem
Conventional methods for reducing the stiffness of gimbal portions in hard disk drives face limitations in achieving desired mechanical and electrical characteristics, particularly due to the constraints of thinning metal bases and conductive circuit portions, which affect the flexibility and electrical properties of the suspension components.
Innovation Solution
A flexure structure for a disk drive suspension is developed, featuring a metal base with a conductive circuit portion comprising an insulating layer and conductors of varying thicknesses, where thin conductors are used in unsupported regions and thick conductors in areas like bent portions or near openings, to reduce stiffness and improve impedance matching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the thickness of the metal base is reduced to decrease the stiffness of the gimbal portion, then the flexibility of the gimbal portion is improved, but the structural strength and stability are compromised
Solution Approach 1:
The patent applies local quality by varying the thickness of the metal base in different regions. The metal base has a first thickness in the gimbal portion region to provide flexibility, and a second thickness (greater than the first) in the support portion region to provide structural strength. This allows each region to have the thickness appropriate for its specific functional requirements.
2Ease of operation
If the thickness of the conductive circuit portion is reduced to decrease the stiffness of the gimbal portion, then the flexibility is improved, but the electrical properties (impedance) are adversely affected
Solution Approach 1:
The conductive circuit portion applies local quality by having different thicknesses in different regions. It has a first thickness in the gimbal portion region to provide flexibility and match the metal base, and a second thickness (greater than the first) in the support portion region to maintain proper electrical impedance and signal integrity.
Solution Approach 2:
The conductive circuit portion is formed as a composite structure with multiple layers of different thicknesses. This composite construction allows the circuit to simultaneously achieve the flexibility needed for gimbal movement and the electrical properties needed for reliable signal transmission.
3Adaptability or versatility
If the metal base is thinned to reduce stiffness, then the degree of freedom for stiffness optimization is improved, but the influence of conductive circuit portion stiffness on overall gimbal stiffness increases adversely
Solution Approach 1:
By making the metal base thicker in the support portion, the patent isolates the stiffness control of the gimbal portion from the influence of the conductive circuit portion. The support portion acts as a stiff foundation that minimizes the relative stiffness contribution of the conductive circuit, simplifying the overall stiffness optimization process.
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 enhances mechanical flexibility and electrical characteristics by reducing the stiffness of the conductive circuit portions, allowing for better control of gimbal movement and improved impedance matching, thereby addressing the limitations of previous technologies.
Implementation Method 1
by a first copper plating, a thin conductor (a thin copper layer) is formed. After that, by second copper plating which uses the second resist pattern, a thick conductor (a thick copper layer) is formed
Data Source
AI summary
A flexure mounted on a load beam of a disk drive suspension, including a metal base formed of a stainless-steel plate; and a conductive circuit arranged along the metal base. The conductive circuit includes an insulating layer on the metal base; and a conductor on the insulating layer. The conductor includes a thin conductor portion formed in a first region (A1) which is part of the conductive circuit in a longitudinal direction; and a thick conductor portion formed in a second region (A2) which is another part of the conductive circuit in the longitudinal direction, the thick conductor portion being thicker than the thin conductor portion. The flexure includes a flexure tail portion having an opening formed in the metal base; a bent portion of the metal base which is bent in a thickness direction at the opening; and a trace curved portion curved in the thickness direction at a position facing the opening. The trace curved portion includes the thick conductor portion.