公开(公告)号：US20140085750A1

公开(公告)日：2014-03-27

申请号：US14094960

申请日：2013-12-03

Applicant: HOYA CORPORATION

Inventor： Kouji KITSUNAI ,  Takashi MAEDA

IPC: G11B5/73 ,  G11B5/82

CPC classification number: G11B5/7315 ,  G11B5/82

Abstract: A glass substrate for a magnetic disk, wherein, in regions with respect to two places arbitrarily selected on a surface of the glass substrate on its central portion side relative to its outer peripheral end, a surface shape with a shape wavelength in a band of 60 to 500 μm is extracted from surface shapes in each of the regions and, assuming that a root mean square roughness Rq of the surface shape is given as a microwaviness Rq, the difference between the microwavinesses Rq of the regions is 0.02 nm or less or the difference between standard deviations of the microwavinesses Rq of the regions is 0.04 nm or less.

Abstract translation: 一种磁盘用玻璃基板，其特征在于，在相对于其外周端部的中央部侧的玻璃基板的表面上任意选择的两个位置的区域中，形状波长为60nm的波长的表面形状 在每个区域中从表面形状提取至500μm，并且假设表面形状的均方根粗糙度Rq作为微波特性Rq，则区域的微波特性Rq之差为0.02nm以下，或者 区域的微波的标准偏差之间的差异为0.04nm以下。

公开(公告)号：US20140220386A1

公开(公告)日：2014-08-07

申请号：US14246742

申请日：2014-04-07

Applicant: HOYA CORPORATION

Inventor： Kouji KITSUNAI ,  Hiroshi Takeda ,  Yukari Senda

IPC: G11B5/73 ,  C03C3/083 ,  G11B5/82

CPC classification number: G11B5/7315 ,  C03C3/083 ,  G11B5/82 ,  G11B20/1816 ,  G11B2220/2516 ,  Y10T428/21

Abstract: The shape and number of surface defects are controlled so that the occurrence of failure is suppressed in an HDD device in which a magnetic head with a very small flying height, such as a DFH head, is mounted.A magnetic disk substrate is characterized in that when laser light with a wavelength of 405 nm and a laser power of 25 mW is irradiated with a spot size of 5 μm and scattered light from the substrate is detected, the number of defects detected to have a size of 0.1 μm to not more than 0.3 μm is less than 50 per 24 cm2 and, with respect to the defects, there is no defect in which, in a bearing curve obtained by a bearing curve plot method using an atomic force microscope, a portion from an apex of the defect to 45% thereof is located in an area of defect height higher than a virtual line connecting from the apex of the defect to 45% thereof.

Abstract translation: 控制表面缺陷的形状和数量，使得在安装有诸如DFH头的飞行高度非常小的磁头的HDD装置中，可以抑制故障的发生。 磁盘基板的特征在于，当以5μm的点尺寸照射波长为405nm，激光功率为25mW的激光，并检测到来自基板的散射光时，检测出具有 0.1μm〜0.3μm的尺寸小于每24cm 2的50个，对于缺陷，没有缺陷，在通过使用原子力显微镜的轴承曲线绘图法得到的轴承曲线中， 从缺陷的顶点到其45％的部分位于高于从缺陷的顶点连接到其缺陷的虚拟线的缺陷高度的45％的区域中。