Abstract: A substrate for use as a disk substrate in a hard disk drive or the like, an information recording medium such as a magnetic disk, and a starting material glass plate which is a starting material of the substrate for information recording media. The forming conditions of the starting material glass plate are controlled such that the starting material glass plate has a long-wavelength waviness of not more than 6 nm. This starting material glass plate is polished so as to have a long-wavelength waviness of not more than 6 nm using CeO2 abrasive grains having a mean grain diameter of not less than 0.01 ?m and a 90% diameter of the volume grain size distribution of not less than 0.02 ?m. The resulting substrate for an information recording medium has an excellent planarity, can be obtained in a short time and with a low polishing amount, and the resulting information recording medium is able to cope with increased data zone recording density.

Abstract: A substrate for use as a disk substrate in a hard disk drive or the like, an information recording medium such as a magnetic disk, and a starting material glass plate which is a starting material of the substrate for information recording media. The forming conditions of the starting material glass plate are controlled such that the starting material glass plate has a long-wavelength waviness of not more than 6 nm. This starting material glass plate is polished so as to have a long-wavelength waviness of not more than 6 nm using CeO2 abrasive grains having a mean grain diameter of not less than 0.01 ?m and a 90% diameter of the volume grain size distribution of not less than 0.02 ?m. The resulting substrate for an information recording medium has an excellent planarity, can be obtained in a short time and with a low polishing amount, and the resulting information recording medium is able to cope with increased data zone recording density.

Abstract: A substrate for use as a disk substrate in a hard disk drive or the like, an information recording medium such as a magnetic disk, and a starting material glass plate which is a starting material of the substrate for information recording media. The forming conditions of the starting material glass plate are controlled such that the starting material glass plate has a long-wavelength waviness of not more than 6 nm. This starting material glass plate is polished so as to have a long-wavelength waviness of not more than 6 nm using CeO2 abrasive grains having a mean grain diameter of not less than 0.01 ?m and a 90% diameter of the volume grain size distribution of not less than 0.02 ?m. The resulting substrate for an information recording medium has an excellent planarity, can be obtained in a short time and with a low polishing amount, and the resulting information recording medium is able to cope with increased data zone recording density.

Abstract: A substrate for use as a disk substrate in a hard disk drive or the like, an information recording medium such as a magnetic disk, and a starting material glass plate which is a starting material of the substrate for information recording media. The forming conditions of the starting material glass plate are controlled such that the starting material glass plate has a long-wavelength waviness of not more than 6 nm. This starting material glass plate is polished so as to have a long-wavelength waviness of not more than 6 nm using CeO2 abrasive grains having a mean grain diameter of not less than 0.0l ?m and a 90% diameter of the volume grain size distribution of not less than 0.02 ?m. The resulting substrate for an information recording medium has an excellent planarity, can be obtained in a short time and with a low polishing amount, and the resulting information recording medium is able to cope with increased data zone recording density.

Abstract: The present invention relates to a substrate for information recording media for use as a disk substrate in a hard disk drive or the like and a manufacturing method thereof, an information recording medium such as a magnetic disk, and a starting material glass plate for use as a starting material of the substrate for information recording media. By suitably controlling forming conditions of the starting material glass plate, the starting material glass plate can be manufactured so as to have a long-wavelength waviness of not more than 6 nm. By carrying out precision polishing on this starting material glass plate having a long-wavelength waviness of not more than 6 nm using CeO2 abrasive grains having a mean grain diameter of not less than 0.01 &mgr;m and a 90% diameter of the volume grain size distribution of not more than 0.02 &mgr;m, a substrate for information recording media having an excellent planarity can be obtained in a short time and with a low polishing amount.