Magnetic Recording Medium Viscosity Control
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Solution Overview
Problem
Magnetic recording media with reduced thickness face challenges in maintaining recording and reproduction capabilities over long-term preservation due to deformation issues, particularly when exposed to temperature variations, leading to strain and potential failure in reading servo signals.
Innovation Solution
A magnetic recording medium with a specific configuration including a magnetic layer, ground layer, base layer, and back layer, where the average thickness is less than 5.3 μm, and exhibits controlled viscosity and elasticity properties within a defined temperature range, ensuring stable performance even after long-term preservation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the overall thickness of the magnetic recording medium is reduced to increase tape length per cartridge, then recording capacity per cartridge is improved, but recording and reproduction performance deteriorates after long-term preservation due to deformation
Solution Approach 1:
The patent applies parameter changes by precisely controlling the viscosity term E'' of the base layer within the range of 0.10 to 0.20 GPa at 20°C, and controlling the difference between maximum and minimum viscosity terms to be 0.15 GPa or less across the temperature range of -40°C to 80°C. These parameter specifications ensure that the magnetic recording medium maintains stable dimensions and prevents deformation during long-term preservation, thereby resolving the contradiction between reduced thickness for increased capacity and maintained reliability for recording performance
Solution Approach 2:
The patent employs composite materials by formulating the base layer with specific polymer compositions that exhibit controlled viscoelastic properties. The base layer is constructed as a composite structure with carefully selected materials that provide both the required mechanical flexibility for thin construction and the dimensional stability needed for long-term preservation, thus enabling both increased recording capacity and maintained reproduction reliability
2Length of moving object
If the magnetic recording medium is made thinner, then the tape length per cartridge is increased, but strain and deformation occur during temperature variations leading to failure in reading servo signals
Solution Approach 1:
The patent utilizes parameter changes by specifying the viscosity term E'' of the base layer to be within 0.10 to 0.20 GPa at 20°C, and controlling the temperature-dependent viscosity variation to be 0.15 GPa or less between -40°C and 80°C. These parameter controls enable the thin magnetic recording medium to resist thermal deformation and maintain dimensional stability across temperature variations, preventing servo signal reading failures while maximizing tape length per cartridge
3Productivity
If the overall thickness is reduced to less than 5.3 μm, then the recording capacity per cartridge is increased, but the medium becomes more susceptible to deformation under external loads
Solution Approach 1:
The patent applies parameter changes by precisely controlling the viscosity term E'' of the base layer to be within the range of 0.10 to 0.20 GPa at 20°C, and controlling the difference between maximum and minimum viscosity terms across the temperature range to be 0.15 GPa or less. These parameter specifications provide the thin magnetic recording medium (thickness less than 5.3 μm) with adequate resistance to deformation under external loads during handling and preservation, while maintaining the reduced thickness for increased recording capacity
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 medium maintains effective recording and reproduction capabilities despite thinness by minimizing strain and deformation, allowing for extended use without degradation in performance.
Implementation Method 1
when the magnetic recording medium is subjected to dynamic viscoelasticity measurement at a frequency of 10 Hz and a temperature rise rate of 2° C./min, a difference between a maximum and a minimum of a viscosity term E′′ in a temperature range of 0° C. to 80° C. is equal to or less than 0.18 GPa
Data Source
AI summary
It is an object to provide a magnetic recording medium that enables good reproduction even after long-term preservation and that has a small overall thickness.The present technology provides a tape-shaped magnetic recording medium including a magnetic layer, a ground layer, a base layer, and a back layer, in which an average thickness tT of the magnetic recording medium is equal to or less than 5.3 μm, and, when the magnetic recording medium is subjected to dynamic viscoelasticity measurement at a frequency of 10 Hz and a temperature rise rate of 2° C./min, a difference between a maximum and a minimum of a viscosity term E″ in a temperature range of 0° C. to 80° C. is equal to or less than 0.18 GPa. In addition, the present technology also provides a tape cartridge including the tape-shaped magnetic recording medium.