Manufacturing method of glass substrate for HDD, glass substrate for HDD, and magnetic recording medium for HDD
A technology of magnetic recording medium and glass substrate, applied in the direction of magnetic recording layer, record carrier manufacturing, base layer of recording layer, etc., can solve problems such as head collision
Active Publication Date: 2016-11-30
HOYA CORP
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Problems solved by technology
In this DFH head mechanism, the gap between the magnetic head and the recording medium is as small as about a few nm, and head crashes (head crash) caused by poor tracking of the magnetic head on the surface of the recording medium are prone to occur.
Method used
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Embodiment
[0161] Hereinafter, the present invention will be described in further detail by way of Examples and Comparative Examples. However, the present invention is not limited to this example.
[0162]
[0163] according to figure 1 The manufacturing process of the glass substrate for HDD was manufactured.
[0164] [1. Glass melting process, molding process]
[0165] The molten glass material was press-molded using aluminosilicate glass having Tg of 480°C as the glass material to produce a disk-shaped glass substrate (blank) with an outer diameter of 68 mm and a thickness of 0.93 mm.
[0166] [2. Heat treatment process]
[0167] A shaper of 70 mm in shape, 2 mm in thickness, and a glass substrate made of alumina were alternately stacked, and the glass substrate was warped in an electric furnace set at a high temperature of about 430° C. for 2 hours. buckling or reduced internal stress.
[0168] [3. The first polishing step]
[0169] Both surfaces of the glass substrate were p...
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Abstract
The present invention provides a method for producing a glass substrate for HDD, a glass substrate for HDD, and a magnetic recording medium for HDD capable of suppressing occurrence of head collision even when the magnetic recording medium for HDD is mounted on an HDD having a DFH head mechanism. The method of manufacturing a glass substrate for HDD includes a chemical strengthening step in which the glass substrate is immersed in a chemical strengthening treatment solution to chemically strengthen the glass substrate. In the chemical strengthening step, the glass substrate immersed in the chemical strengthening treatment solution is changed to The posture in the liquid, the uniform temperature distribution of the chemical strengthening treatment liquid, and / or the stirring of the chemical strengthening treatment liquid are such that the increase in TIR in the circumferential direction of the glass substrate before and after the chemical strengthening process is 0.5 μm or less.
Description
technical field [0001] The present invention relates to a method for producing a glass substrate for HDD, a glass substrate for HDD, and a magnetic recording medium for HDD. Background technique [0002] In general, a magnetic recording medium for HDD (hard disk drive) is known as a representative recording medium of an information recording medium having a recording layer utilizing magnetic, optical, magneto-optical and other properties. Conventionally, aluminum substrates have been widely used as substrates for HDDs used to manufacture magnetic recording media for HDDs. However, in recent years, in response to the demand for reducing the amount of magnetic head flying in order to increase the recording density, the proportion of glass substrates that can reduce the amount of magnetic head flying has been increasing as a substrate for HDDs. This is because the surface smoothness of glass substrates is higher than that of aluminum substrates. Excellent with few surface defe...
Claims
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IPC IPC(8): G11B5/84C03C19/00C03C21/00G11B5/73
Inventor 福本直之
Owner HOYA CORP