Hard Disk Drive Multilayer Substrate Noise Shielding
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Solution Overview
Problem
Conventional hard disk drives in mobile telephones face challenges in reducing size and thickness due to the difficulty in miniaturizing platters and motors, and they suffer from high-frequency noise interference from digital ICs, which affects transmission quality, especially in frequency spread coding systems like CDMA.
Innovation Solution
A small, thin hard disk drive design utilizing a multilayer substrate with digital ICs embedded as bare chips and a bus line configuration that minimizes noise interference by using first and second ground layers to shield the bus lines, eliminating the need for a second circuit substrate and allowing direct connections between ICs, thereby reducing noise impact on analog circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If digital ICs are mounted on a circuit substrate outside the casing, then the number of components that can be mounted is increased, but the thickness of the hard disk drive increases and noise interference occurs
Solution Approach 1:
The patent combines the first circuit substrate (inside the casing) and the second circuit substrate (outside the casing) into a single integrated circuit substrate. This merging allows all components to be mounted on one substrate within the casing, reducing the overall thickness of the hard disk drive while maintaining the functionality of having multiple components.
Solution Approach 2:
The patent embeds digital ICs as bare chips directly into the circuit substrate, nesting them within the substrate structure rather than mounting them on the surface. This nesting approach reduces the vertical space required, thereby reducing the thickness of the hard disk drive while still accommodating multiple components.
2Adaptability or versatility
If digital ICs are mounted on a circuit substrate, then the functionality of the hard disk drive is enhanced, but high-frequency noise interference is generated that affects transmission quality
Solution Approach 1:
The patent extracts the digital ICs from the general circuit substrate area and places them in a dedicated digital circuit region. This separation extracts the noise-generating elements to a specific zone, making it easier to apply noise countermeasures such as ground layers and shielding without affecting the entire circuit substrate.
Solution Approach 2:
The patent introduces ground layers and shielding structures as intermediary elements between the digital ICs and other circuit components. These intermediaries act as barriers that block or absorb high-frequency noise, preventing it from interfering with analog circuits and other sensitive components.
3Quantity of substance
If the first circuit substrate has a large surface area to accommodate multiple components, then the number of components that can be mounted is increased, but the available space inside the casing is reduced
Solution Approach 1:
The patent transitions from a two-dimensional layout of components on the circuit substrate to a three-dimensional structure by embedding digital ICs as bare chips within the substrate. This dimensional change allows for higher component density without increasing the surface area, thereby preserving more space inside the casing.
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 achieves high-density mounting and reduces high-frequency noise, enabling a small, thin wireless data terminal with improved transmission quality by effectively shielding noise and minimizing the thickness of the hard disk drive and mobile telephone.
Implementation Method 1
a bus line for connecting the digital ICs, wherein the digital ICs are disposed in a mutually horizontal configuration... first and second ground layers to shield the bus lines
Implementation Method 2
a voice coil motor for slidably driving the arm 14
Implementation Method 3
an arm 14 with a magnetic head 13 attached to a distal end thereof
Data Source
AI summary
A hard disk drive is provided with a platter, a spindle motor for driving the platter, an arm with a magnetic head attached to a distal end thereof, a voice coil motor for driving the arm, a first circuit substrate, and a drive casing for accommodating and electrically shielding the platter, spindle motor, arm, voice coil motor, and first circuit substrate. The first circuit substrate has a multilayer substrate, a plurality of digital ICs that are embedded as bare chips in the multilayer substrate, and a bus line for connecting the digital ICs. The digital ICs are disposed in a mutually horizontal configuration.