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Glass substrate for magnetic disk and magnetic disk

A technology for glass substrates and magnetic disks, applied in magnetic recording, magnetic recording layers, base layers of recording layers, etc., can solve problems such as difficult disk speeding, reduced suspension stability of magnetic heads, and reduced linear speed

Inactive Publication Date: 2008-12-03
HOYA CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0019] In the case of magnetic disks with an outer diameter of 50 mm or less used in such small hard disk drives, the relative linear velocity between the magnetic disk and the magnetic head decreases due to the reduction in the outer and inner diameters.
In addition, as the diameter of the magnetic disk decreases, the size of the spindle motor that rotates the magnetic disk is also reduced, and it is not easy to further increase the rotational speed of the magnetic disk.
Therefore, there is a possibility that the influence on the levitation posture or levitation amount, and the occurrence of the above-mentioned fly pasting failure cannot be sufficiently prevented
[0020] Furthermore, since the magnetic head is also miniaturized along with the reduction in the diameter of the magnetic disk, the suspension stability of the magnetic head may decrease.

Method used

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  • Glass substrate for magnetic disk and magnetic disk
  • Glass substrate for magnetic disk and magnetic disk
  • Glass substrate for magnetic disk and magnetic disk

Examples

Experimental program
Comparison scheme
Effect test

no. 1 Embodiment

[0145] Hereinafter, it demonstrates concretely by giving an Example and a comparative example. Furthermore, the present invention is not limited to the configurations of these examples.

Embodiment 1

[0146] [Example 1 (Example of Glass Substrate for Magnetic Disk)]

[0147] The glass substrate for magnetic discs of the present Example described below was produced through the following steps (1) to (8).

[0148] (1) Rough grinding process

[0149] (2) Shape processing process

[0150] (3) Fine grinding process

[0151] (4) End mirror surface processing process

[0152] (5) The first grinding process

[0153] (6) Second grinding process

[0154] (7) Chemical strengthening process

[0155] (8) Texture processing

[0156] First, a disk-shaped glass base material made of amorphous aluminosilicate glass is prepared. This aluminosilicate glass contains lithium. The composition of the aluminosilicate glass is to contain 63.6% by weight of SiO 2 , 14.2 wt% Al 2 o 3 , 10.4 wt% Na 2 O, 5.4 wt% Li 2 O, 6.0 wt% ZrO 2 , 0.4 wt% Sb 2 o 3 .

[0157] (1) Rough grinding process

[0158] A plate glass having a thickness of 0.6 mm formed from molten aluminosilicate glass was...

Embodiment 2

[0200] [Example 2 (Example of Glass Substrate for Magnetic Disk)]

[0201] As shown in (Table 1), Example 2 in which only the conditions of texture processing were changed in Example 1 was produced.

[0202] In this embodiment 2, the condition of texture processing is to use fabric belt as abrasive belt, use polycrystalline diamond slurry as abrasive (slurry), set the rotating speed of glass plate as 883 revolutions per minute, make glass plate The shaking (vibration) frequency of the glass plate was set to 7.8 Hz, the amplitude of the shaking (vibration) of the glass plate was set to 1 mm, and the processing weight by the pressure roller was set to 3.675 kg (1.5 pounds).

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Abstract

A glass substrate for a magnetic disk, wherein the surface roughness of the substrate in the circumferential direction is increased from the outer peripheral side to the inner peripheral side by forming an anisotropic texture on the main surface thereof in the approximately circumferential direction. Also, the ratio (Ra-c / Ra-r) of the arithmetic average roughness (Ra-c) of the surface in the circumferential direction to the arithmetic average roughness (Ra-r) of the surface in the radial direction is increased from the outer peripheral side to the inner peripheral side of the main surface.

Description

technical field [0001] This invention relates to the glass substrate for magnetic discs used for the hard disk drive (HDD) which is a magnetic disc device, and a magnetic disc. Background technique [0002] In recent years, information recording technology, especially magnetic recording technology, requires rapid technological innovation along with the development of the so-called IT industry. In addition, unlike other magnetic and magnetic recording media such as magnetic tapes and floppy disks, magnetic disks mounted on hard disk drives (HDDs) used as computer memories and as magnetic disk devices continue to increase rapidly in information recording density. The amount of information that can be accommodated in a personal computer device has increased dramatically, supported by the above-mentioned increase in information density. [0003] Such a magnetic disk is constructed by forming a magnetic layer or the like on a substrate such as an aluminum-based alloy substrate. ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G11B5/73
CPCG11B5/7315G11B5/73921Y10T428/11Y10T428/24355
Inventor 田中宏尚小泽强高野正夫
Owner HOYA CORP
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