Disk Device Heat Dissipation Layer for FPC Soldering
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Solution Overview
Problem
The existing bonding process for flexible printed circuit boards (FPCs) in disk devices, such as hard disk drives, faces issues with overheating during soldering, which can cause the FPCs to peel off due to uneven heat distribution and thermal conductivity disparities.
Innovation Solution
Incorporating a ground plane that is strategically positioned to cover certain terminals and wires, thereby distributing heat more evenly and preventing excessive heating, while maintaining electrical insulation to avoid impedance and signal interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If laser light is used to heat solder for bonding FPC terminals, then bonding strength is improved, but temperature control precision deteriorates causing overheating and FPC peel-off
Solution Approach 1:
A heat dissipation layer is introduced as an intermediary component between the FPC terminals and the surrounding structure. This layer mediates the heat transfer during laser soldering, absorbing excess heat and preventing direct thermal damage to the FPC while still enabling sufficient heating for bonding.
Solution Approach 2:
The heat dissipation layer converts the harmful effect of excessive heat into a beneficial thermal management mechanism. By strategically positioning the layer to cover specific terminals, it directs heat away from sensitive areas while maintaining bonding temperature, effectively turning potential damage into controlled thermal dissipation.
2Temperature
If ground plane covers terminals to distribute heat, then heat distribution uniformity is improved, but electrical insulation deteriorates causing impedance and signal interference
Solution Approach 1:
The heat dissipation layer is applied locally only to specific terminals that require heat dissipation, rather than covering the entire FPC surface. This localized approach provides targeted thermal management while preserving electrical insulation in areas where ground coverage would cause interference.
Solution Approach 2:
The FPC structure is segmented into different functional zones: areas with heat dissipation layer coverage for thermal management, and areas without coverage for electrical signal integrity. This segmentation allows simultaneous optimization of both thermal and electrical performance in different regions.
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 solution effectively prevents the FPCs from peeling off during the soldering process, ensuring reliable bonding and maintaining signal integrity by managing heat distribution and reducing parasitic capacitance.
Implementation Method 1
the ground plane covers at least one of the plurality of second terminals in a direction orthogonal to the surface... effectively prevents the FPCs from peeling off during the soldering process, ensuring reliable bonding and maintaining signal integrity by managing heat distribution
Implementation Method 2
In bonding the terminals of the two FPCs by soldering, the solder is heated by laser light, for example
Data Source
AI summary
According to one embodiment, a disk device includes a magnetic disk, a magnetic head, a first FPC, and a second FPC. The first FPC includes first terminals. The magnetic head is mounted on the first FPC and electrically connected to at least one of the first terminals. The second FPC includes a surface, second terminals on the surface, and a first ground plane. The second terminals are individually bonded to the corresponding first terminals with a conductive bonding material. The first ground plane covers at least one of the second terminals in a direction orthogonal to the surface. The second terminals include a first read terminal through which an electric signal representing information read from the magnetic disk by the magnetic head passes. The first ground plane is located apart from at least a part of the first read terminal in a direction along the surface.