Hoya Corporation

Hoya Glass Disk Vietnam Ii Ltd.

Lixil Nittan Company, Limited

Masahiro Katagiri

Toshio Takizawa

Yoshinori Marumo

Takumi Koshimizu

Hiroshi Kaneko

Kazuyoshi Sakurai

Nobuyuki Akiyama

Akihisa Kudoh

Masayoshi Yoshida

Shozo Iwabuchi

A glass substrate for use as a magnetic disk for heat assisted magnetic recording can restrain the occurrence of scratches when a magnetic head is in operation. The glass substrate for the magnetic disk includes a principal face on which an arithmetic average waviness Wa of a wavelength band of 1 to 3 mm is 2.15 &#x212b; or less.

Glass substrate for magnetic disk and magnetic disk for heat assisted magnetic recording

When mirror polishing is performed on a glass substrate by bringing a polishing pad into contact with the surface of the glass substrate while supplying a polishing liquid containing polishing grains to the substrate surface, the pH of the polishing liquid is maintained within a certain range or the agglomeration degree or dispersion degree of the polishing liquid is controlled. Consequently, an adequate mirror polishing rate can be maintained and there can be obtained a glass substrate having a good end shape.

Method for producing glass substrate for magnetic disk and method for manufacturing magnetic disk

A flame detector is provided. A circuit board is disposed in a housing. A first light source emits first light. A light guide member comprised of translucent material guides the first light from the first light source to a light emission portion of the light guide member. A first light receiving element detects second light having a predetermined wavelength unique to the flames. A second light source emits third light to a translucent cover which is disposed between an opening of the housing and the first light receiving element. A second light receiving element detects the third light passed through the translucent cover to test the translucency. The first light source, the second light source and the second light receiving element are mounted on the circuit board. The light emission portion is formed into a substantially annular shape which encloses the first light receiving element at a front side of the housing to limit a field of view of the first light receiving element to a predetermined range. And the light guide member has a light entrance portion and a light exit portion for the third light to form a light path from the second light source to the second light receiving element through the translucent cover and the light guide member.

Flame detector

In a method of grinding side end surfaces of substrates, spacers are interposed between the substrates to form a stack of the substrates and the spacers. The spacers are slightly smaller in size than the substrates. The stack of the substrates and the spacers are ground by a rotatable brush or pad on the side end surfaces of the substrates so as to smooth chamfered portions of the substrates together with the side end surfaces.

Method of grinding a substrate and method of manufacturing a glass substrate and a magnetic recording medium by the use of the glass substrate

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Tokyo, Japan

Masahiro Katagiri