Abstract: A glass substrate for an information recording medium is manufactured by polishing the surface of a raw material glass plate. The polishing of the raw material glass plate is divided into a step for performing a first polishing process to roughly polish the surface of the raw material glass plate to be smooth and a step for performing a second polishing process to finely polish the surface of the roughly polished raw material glass plate to be smoother. The first polishing process uses a polishing pad made of a synthetic resin foam and slides the polishing pad on the raw material glass plate surface while supplying a polishing agent to roughly polish the surface. A pad dressing process is performed on the polishing pad before being used in the first polishing process. The pad dressing process polishes the surface of the polishing pad by sliding the polishing pad on a pad dresser including abrasive grains.

Abstract: An information recording medium glass substrate manufactured by polishing the surface of a raw material glass plate. The polishing is divided into two steps, a step for performing a first polishing process to roughly polish the surface of the raw material glass plate to be smooth and a step for performing a second polishing process to finely polish the surface of the roughly polished raw material glass plate to be smoother. The second polishing process, using a polishing pad made of foam, is divided into two stages, pre-polishing with a polishing agent including abrasive grains of cerium oxide and post-polishing with a polishing agent including abrasive grains of silicon oxide. A rinsing process is performed between the pre-polishing and the post-polishing to rinse the raw material glass plate after the pre-polishing with a washing liquid to wash away the abrasive grains collected in the polishing pad in pre-polishing during the rinsing process.

Abstract: A glass substrate for an information recording medium is manufactured by polishing the surface of a raw material glass plate. The polishing of the raw material glass plate is divided into a step for performing a first polishing process to roughly polish the surface of the raw material glass plate to be smooth and a step for performing a second polishing process to finely polish the surface of the roughly polished raw material glass plate to be smoother. The first polishing process uses a polishing pad made of a synthetic resin foam and slides the polishing pad on the raw material glass plate surface while supplying a polishing agent to roughly polish the surface. A pad dressing process is performed on the polishing pad before being used in the first polishing process. The pad dressing process polishes the surface of the polishing pad by sliding the polishing pad on a pad dresser including abrasive grains.

Abstract: A glass substrate for an information recording medium is manufactured by polishing the surface of a raw material glass plate. The polishing of the raw material glass plate is divided into a step for performing a first polishing process to roughly polish the surface of the raw material glass plate to be smooth and a step for performing a second polishing process to finely polish the surface of the roughly polished raw material glass plate to be smoother. The first polishing process uses a polishing pad made of a synthetic resin foam and slides the polishing pad on the raw material glass plate surface while supplying a polishing agent to roughly polish the surface. A pad dressing process is performed on the polishing pad before being used in the first polishing process. The pad dressing process polishes the surface of the polishing pad by sliding the polishing pad on a pad dresser including abrasive grains.

Abstract: A polishing pad is used when a surface of a glass workpiece is polished for manufacturing a glass substrate of information recording medium. The polishing pad has a nap layer. The nap layer includes an inner layer that contains a plurality of closed cells, and an outer layer. A plurality of pores are formed on the surface of the outer layer. The sizes of the pores are minute compared to those of the closed cells.

Abstract: A glass substrate for an information recording medium is manufactured by polishing the surface of a raw material glass plate. The polishing of the raw material glass plate is divided into a step for performing a first polishing process to roughly polish the surface of the raw material glass plate to be smooth and a step for performing a second polishing process to finely polish the surface of the roughly polished raw material glass plate to be smoother. The first polishing process uses a polishing pad made of a synthetic resin foam and slides the polishing pad on the raw material glass plate surface while supplying a polishing agent to roughly polish the surface. A pad dressing process is performed on the polishing pad before being used in the first polishing process. The pad dressing process polishes the surface of the polishing pad by sliding the polishing pad on a pad dresser including abrasive grains.

Abstract: An information recording medium glass substrate manufactured by polishing the surface of a raw material glass plate. The polishing is divided into two steps, a step for performing a first polishing process to roughly polish the surface of the raw material glass plate to be smooth and a step for performing a second polishing process to finely polish the surface of the roughly polished raw material glass plate to be smoother. The second polishing process, using a polishing pad made of foam, is divided into two stages, pre-polishing with a polishing agent including abrasive grains of cerium oxide and post-polishing with a polishing agent including abrasive grains of silicon oxide. A rinsing process is performed between the pre-polishing and the post-polishing to rinse the raw material glass plate after the pre-polishing with a washing liquid to wash away the abrasive grains collected in the polishing pad in pre-polishing during the rinsing process.

Abstract: A glass substrate for a data recording medium is disk-shaped and has a circular bore at the center portion. At least one of an inner circumferential end surface and an outer circumferential end surface is smooth. The smooth surface is formed by exposing at least one of the inner circumferential end surface and the outer circumferential end surface of a glass disk to a laser beam. During laser machining, the end surface of the glass disk that is exposed to the laser beam is heated and melted. Therefore, minute cracks, formed on the end surface of the glass disk before the laser machining, are eliminated. As a result, the strength of the glass substrate is maintained without a chemical strengthening treatment. This eliminates disadvantages caused by the chemical strengthening step.

Abstract: A glass substrate for a data recording medium is manufactured by using a tabular carrier with circular holes formed therein, housing disk-shaped glass workpieces in the circular holes of this carrier, sliding polishing pads over the surface of the carrier and the principal surfaces of the glass workpieces and polishing the glass workpieces until the height (NRa) of micro-waviness on the principal surfaces of the glass workpieces is reduced to a predetermined value or less. The height (NRa) of micro-waviness of the principal surfaces is a value dependent on the surface roughness of the polishing pad and the surface roughness of this polishing pad is a value dependent on the surface roughness of the carrier. A glass substrate for a data recording medium is manufactured by reducing the surface roughness (Ra) of the carrier to 0.

Abstract: A glass substrate for a data recording medium is manufactured by using a tabular carrier with circular holes formed therein, housing disk-shaped glass workpieces in the circular holes of this carrier, sliding polishing pads over the surface of the carrier and the principal surfaces of the glass workpieces and polishing the glass workpieces until the height (NRa) of micro-waviness on the principal surfaces of the glass workpieces is reduced to a predetermined value or less. The height (NRa) of micro-waviness of the principal surfaces is a value dependent on the surface roughness of the polishing pad and the surface roughness of this polishing pad is a value dependent on the surface roughness of the carrier. A glass substrate for a data recording medium is manufactured by reducing the surface roughness (Ra) of the carrier to 0.

Abstract: A polishing pad is used when a surface of a glass workpiece is polished for manufacturing a glass substrate of information recording medium. The polishing pad has a nap layer. The nap layer includes an inner layer that contains a plurality of closed cells, and an outer layer. A plurality of pores are formed on the surface of the outer layer. The sizes of the pores are minute compared to those of the closed cells.

Abstract: A glass substrate for a data recording medium is disk-shaped and has a circular bore at the center portion. At least one of an inner circumferential end surface and an outer circumferential end surface is smooth. The smooth surface is formed by exposing at least one of the inner circumferential end surface and the outer circumferential end surface of a glass disk to a laser beam. During laser machining, the end surface of the glass disk that is exposed to the laser beam is heated and melted. Therefore, minute cracks, formed on the end surface of the glass disk before the laser machining, are eliminated. As a result, the strength of the glass substrate is maintained without a chemical strengthening treatment. This eliminates disadvantages caused by the chemical strengthening step.