Substrate for magnetic recording medium, magnetic recording medium, method of manufacturing magnetic recording medium, and method of inspecting surface
US8951652B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 28, 2012 |
| Grant date | Feb 10, 2015 |
| Priority date | — |
| Expiry date | Nov 28, 2032 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/24355
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A substrate for a magnetic recording medium having a disc shape with a central hole is provided in which the surface roughness of the principal surface of the substrate is 1 angstrom or less in terms of root mean square roughness (Rq) when a space period (L) of an undulation in the circumferential direction is in the range 10 to 1,000 μm, and in which when a component in the vertical axis direction of a line segment Z connecting a point A with the space period (L) of 10 μm and a point B with the space period (L) of 1,000 μm in a curve S marked on a double logarithmic graph which is obtained by analyzing the surface roughness using a spectrum and in which the horizontal axis is set to the space period (L) (μm) and the vertical axis is set to the power spectrum density (PSD) (k·angstrom2·μm) (where k is a constant) is defined as H and a displacement at which the component in the vertical axis direction of the curve S is the maximum with respect to the line segment Z is defined as ΔH, a value (P) expressed by (ΔH/H)×100 (%) is 15% or less.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.