Hoya Assigned Five Patents

Substrate for magnetic disk and magnetic disk
Hoya Corporation, Tokyo, Japan, has been assigned a patent (10,553,243) developed by Tamaki, Masanori, Higashimurayama, Japan, for “substrate for magnetic disk and magnetic disk.“

The abstract of the patent published by the U.S. Patent and Trademark Office states: ”A magnetic-disk glass substrate capable of suppressing turbulence of air flow in a vicinity of an outer circumferential side edge portion of the magnetic disk and suppressing disk flutter is provided. This magnetic-disk glass substrate includes a pair of main surfaces, a side wall surface formed on an outer circumferential side edge surface, and chamfered surfaces interposed between the side wall surface and the main surfaces, respectively. The side wall surface has a roundness of 1.5 .mu.m or less. A difference in radius between an inscribed circle and a circumcircle of a plurality of outlines of the side wall surface at a plurality of positions that include a central position of the magnetic-disk glass substrate in a thickness direction and are different from each other in the thickness direction is 5 .mu.m or less.”

The patent application was filed on February 28, 2017 (15/444,911).

Substrate for magnetic disk and magnetic disk
Hoya Corporation, Tokyo, Japan, has been assigned a patent (10,535,366) developed by Tamaki, Masanori, Higashimurayama, Japan, Takahashi, Takeyoshi, Akishima, Japan, and Ueda, Masaaki, Yokohama, Japan, for “substrate for magnetic disk and magnetic disk.“

The abstract of the patent published by the U.S. Patent and Trademark Office states: ”A magnetic-disk glass substrate has a circular center hole a pair of main surfaces and an edge surface. The edge surface has a side wall surface and chamfered surfaces interposed between the side wall surface and the main surfaces, and a roundness of an edge surface on an outer circumferential side is 1.5 .mu.m or less. Also, a midpoint A between centers of two least square circle respectively derived from outlines in a circumferential direction respectively obtained at two positions spaced apart by 200 .mu.m in a substrate thickness direction on the side wall surface on the outer circumferential side, and centers B and C respectively derived from a respective one of two chamfered surfaces on the outer circumferential side in the substrate thickness direction, are located such that a sum of respective distances between A and B, and A and C, is 1 .mu.m or less.”

The patent application was filed on February 24, 2017 (15/442,051).

Magnetic-disk substrate and magnetic disk
Hoya Corporation, Tokyo, Japan, has been assigned a patent (10,497,387) developed by Itaya, Masanobu, Minami-Alps, Japan, and Osakabe, Kinobu, Tokorozawa, Japan, for “magnetic-disk substrate and magnetic disk.“

The abstract of the patent published by the U.S. Patent and Trademark Office states: ”A magnetic-disk glass substrate according to the present invention is a doughnut-shaped magnetic-disk glass substrate having a circular hole provided in the center, a pair of main surfaces, and an outer circumferential end surface and an inner circumferential end surface each including a side wall surface and a chamfered surface that is formed between each main surface and the side wall surface. A measurement point is provided on the outer circumferential end surface every 30 degrees in the circumferential direction with reference to a center of the glass substrate, and when a curvature radius of a shape of a portion between the side wall surface and the chamfered surface is determined at each measurement point, the difference in the curvature radius between neighboring measurement points is 0.01 mm or less.”

The patent application was filed on March 23, 2017 (15/467,492).

Substrate for magnetic disk and magnetic disk
Hoya Corporation, Tokyo, Japan, has been assigned a patent (10,431,252) developed by Tamaki, Masanori, Higashimurayama, Japan, Takahashi, Takeyoshi, Akishima, Japan, and Ueda, Masaaki, Yokohama, Japan, for “substrate for magnetic disk and magnetic disk.“

The abstract of the patent published by the U.S. Patent and Trademark Office states: ”A magnetic-disk glass substrate has a circular hole at a center, and includes a pair of main surfaces and a side wall surface orthogonal to the main surfaces. A roundness of the circular hole is 1.5 .mu.m or less. A difference between a maximum value and a minimum value of radii of three inscribed circles that are respectively derived from outlines in the circumferential direction at three positions spaced apart by 200 .mu.m in a substrate thickness direction on the side wall surface of the circular hole is 3.5 .mu.m or less.”

The patent application was filed on February 24, 2017 (15/441,931).

Manufacturing glass substrate and method for manufacturing magnetic disk
Hoya Corporation, Tokyo, Japan, has been assigned a patent (10,403,321) developed by Tawara, Yoshihiro, Hokuto, Japan, for “method for manufacturing glass substrate and method for manufacturing magnetic disk.“

The abstract of the patent published by the U.S. Patent and Trademark Office states: ”A method for manufacturing a glass substrate according to which surface roughnesses of main surfaces of a glass substrate can be reduced more than with currently available methods is provided. After the main surfaces of the glass substrate used in a magnetic disk are mirror-polished, final finishing-polished) using a polishing liquid containing organic-based particles made of, for example, a styrene-based resin, an acrylic resin, or a urethane-based resin as polishing abrasive particles, by cleaning the glass substrate using an organic-based cleaning agent, surface roughnesses of the main surfaces of the substrate can be reduced more than with currently available methods.”

The patent application was filed on September 29, 2014 (15/023,938).