Substrate for magnetic disk
By measuring the arithmetic mean height Sa in the outer peripheral region of the disk substrate using a scanning optical interferometry method, the problem of head collision caused by insufficient rigidity of the thin substrate was solved, and the head collision was effectively suppressed and the reliability of the substrate was improved.
CN120530456BActive Publication Date: 2026-05-05FURUKAWA ELECTRIC CO LTD +1
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Patent Information
- Application Number
- CN202480009835.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Priority Date
- 2023-02-01
- Filing Date
- 2024-01-26
- Publication Date
- 2026-05-05
- Estimated Expiration
- 2044-01-26
AI Technical Summary
Technical Problem
Existing disk substrates lack rigidity after being thinned, making them prone to deformation and making it difficult to effectively suppress the risk of head collisions.
Method used
By measuring the arithmetic mean height Sa in the outer peripheral region of the disk substrate using scanning optical interferometry, and setting the cutoff wavelength to 1.0 mm, the maximum value and standard deviation of the arithmetic mean height Sa are ensured to be within a specific range to suppress fluctuations and reduce the risk of head collision.
Benefits of technology
It effectively suppresses head collisions, improves the reliability and stability of the disk, and is especially suitable for thin substrates with a thickness of less than 0.50 mm.
✦ Generated by Eureka AI based on patent content.
Abstract
The object of this invention is to provide a disk disk substrate that, although particularly thin, effectively suppresses head collisions by effectively suppressing undulations in the outer peripheral region of the disk surface. This invention provides a disk disk substrate in which, using scanning optical interferometry in multiple field-of-view regions located in the outer peripheral region of at least one side, the maximum value of the arithmetic mean height Sa specified in ISO 25178 is less than 0.50 nm in the mid-wavelength region via a Gaussian filter with a cutoff wavelength set to 1.0 mm, and the standard deviation of the aforementioned arithmetic mean height Sa is less than 0.10 nm.
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