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Information recording medium glass substrate, and information recording medium glass substrate manufacturing method

A technology for information recording and glass substrates, which is applied to the base layer of the recording layer, magnetic recording, information storage, etc., and can solve the problems of damage to the stable state of the glass surface, the inability to identify the main cause, and the deviation of the signal-to-noise ratio.

Active Publication Date: 2015-03-04
HOYA CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

It is clear that the above-mentioned deviations in the signal-to-noise ratio of the magnetic signal are caused by damage to the stability of the glass surface during cleaning immediately before the application of such a magnetic layer, even if the glass substrate itself is inspected after manufacture, The main reason cannot be identified

Method used

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  • Information recording medium glass substrate, and information recording medium glass substrate manufacturing method
  • Information recording medium glass substrate, and information recording medium glass substrate manufacturing method
  • Information recording medium glass substrate, and information recording medium glass substrate manufacturing method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0076] In Example 1, after performing the "second polishing process", the glass substrate was rinsed with 1.5 ppm hydrogen-containing water by showering for 3 minutes. Thereafter, the glass substrate was brought into contact with a sodium hydroxide solution having a pH of 10.5 for 5 minutes, and then the glass substrate was brought into contact with 0.1% ascorbic acid for 15 minutes. Thereafter, the final washing of the glass substrate was performed with pure water.

Embodiment 2

[0078] In Example 2, after performing the "second polishing process", the glass substrate was rinsed with pure water by showering. Thereafter, the glass substrate 1G was brought into contact with a sodium hydroxide solution having a pH of 10.5 for 5 minutes, and then the glass substrate was brought into contact with 0.1% ascorbic acid for 15 minutes. Thereafter, the glass substrate was washed with pure water.

Embodiment 3

[0080] In Example 3, after performing the "second polishing process", the glass substrate was rinsed with 1.5 ppm hydrogen-containing water by showering for 3 minutes. Then, the glass substrate was brought into contact with a sodium hydroxide solution of pH 10.5 for 5 minutes, and thereafter, the glass substrate was washed with pure water.

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Abstract

This information recording medium glass substrate is used in an information recording medium which comprises a magnetic recording layer formed on the primary surface of a glass substrate and which has a recording density on the magnetic recording surface of 600Gbit / square inch or greater. If the information recording medium glass substrate undergoes first alkali treatment involving immersion for 30 minutes in a pH11 sodium hydroxide solution at 40°C, the average value of Ra change on the surface of the information recording medium glass substrate after said first alkali treatment is 0.50Å or less, and if the information recording medium glass substrate undergoes second alkali treatment involving immersion for 2.5 hours in a pH12 sodium hydroxide solution at 25°C, the average value of Ra change on the surface of the information recording medium glass substrate after said second alkali treatment is 2.00Å or less.

Description

technical field [0001] This invention relates to the manufacturing method of the glass substrate for information recording media, and the glass substrate for information recording media. Background technique [0002] Conventionally, aluminum substrates or glass substrates have been used for information recording media (magnetic disk recording media) used in computers and the like. A magnetic thin film layer is formed on these substrates, and information is recorded in the magnetic thin film layer by magnetizing the magnetic thin film layer with a magnetic head. [0003] In recent years, in hard disk drive (HDD) devices, the recording density has become higher and higher. Due to higher recording density, the gap (floating height) between an information recording medium (carrier) and a read / write head that floats on the information recording medium to perform recording has been reduced to about several nm. [0004] As the flying height becomes smaller, when the information r...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G11B5/73C03C15/00C03C23/00G11B5/84
CPCC03C23/00G11B5/73G11B5/8404G11B5/7315G11B5/84C03C15/00G11B5/73921
Inventor 岛津典子
Owner HOYA CORP