Glass substrate manufacturing method, glass substrate polishing method, glass substrate polishing apparatus and glass substrate

1. A glass substrate manufacturing method, comprising:

deriving in advance a correlation between a first variable which changes in response to at least one of an electric power and an electric energy required for driving a motor of a polishing apparatus and a second variable which changes in response to an amount of polishing of a glass substrate; and

polishing the glass substrate by driving the motor provided in the polishing apparatus,

wherein the polishing of the glass substrate comprises executing an adjusting operation which adjusts the amount of polishing of the glass substrate in compliance with the correlation between the first variable and the second variable derived in advance.

2. The glass substrate manufacturing method according to claim 1 , wherein the adjusting operation is executed based on at least one of the electric power and the electric energy during the driving of the motor.

3. The glass substrate manufacturing method according to claim 1 , wherein:

the first variable is an average electric power value as a value obtained by dividing the electric energy by a driving time of the motor;

the second variable is a multiplied value obtained by multiplying a number of sheets of the glass substrate by a polishing rate as a value given by dividing the amount of polishing of the glass substrate by the driving time of the motor;

the correlation is relational expressions among the amount of polishing of the glass substrate, the electric energy, and the driving time of the motor, which are specified by deriving coefficients of a recursion formula that represents a relation between the average electric power value and the multiplied value; and

the adjusting operation is a driving operation for driving the motor while substituting sequentially the electric energy and the driving time of the motor into the relational expressions during the driving of the motor until the amount of polishing of the glass substrate derived from the relational expressions reaches a predetermined target value.

4. The glass substrate manufacturing method according to claim 1 , wherein the polishing is in manufacturing processes including a form processing process, a peripheral end surface polishing process, and a cleaning process.

5. The glass substrate manufacturing method according to claim 4 , wherein a chemically strengthening process is in the manufacturing processes.

6. The glass substrate manufacturing method according to claim 1 , wherein the glass substrate is a magnetic recording medium glass substrate.

7. The glass substrate manufacturing method according to claim 1 , wherein the motor is configured to drive a polishing device comprising a platen and an abrasive pad positioned on the platen.

8. A glass substrate polishing method of polishing a glass substrate, comprising:

deriving in advance a correlation between a first variable which changes in response to at least one of an electric power and an electric energy required for driving a motor of a polishing apparatus and a second variable which changes an amount of polishing of a glass substrate; and

adjusting the amount of polishing of the glass substrate in compliance with the correlation derived in advance.

9. The glass substrate polishing method according to claim 8 , wherein the amount of polishing of the glass substrate is adjusted based on at least one of the electric power the electric energy during the driving of the motor.

10. The glass substrate polishing method according to claim 8 , wherein:

the first variable is an average electric power value as a value obtained by dividing the electric energy by a driving time of the motor;

the second variable is a multiplied value obtained by multiplying a number of sheets of the glass substrate by a polishing rate as a value given by dividing the amount of polishing of the glass substrate by the driving time of the motor;

the correlation is relational expressions among the amount of polishing of the glass substrate, the electric energy, and the driving time of the motor, which are specified by deriving coefficients of a recursion formula that represents a relation between the average electric power value and the multiplied value; and

the motor is driven while substituting sequentially the electric energy and the driving time of the motor into the relational expressions during the driving of the motor until the amount of polishing of the glass substrate derived from the relational expressions reaches a predetermined target value.

11. The glass substrate polishing method according to claim 8 , wherein the glass substrate is a magnetic recording medium glass substrate.

12. A glass substrate that is polished by the glass substrate polishing method according to claim 8 .

13. The glass substrate manufacturing method according to claim 8 , wherein the motor is configured to drive a polishing device comprising a platen and an abrasive pad positioned on the platen.

14. A polishing apparatus, comprising:

a polishing device configured to polish a glass substrate;

a motor which drives the polishing device; and

a controlling unit configured to control the motor,

wherein the controlling unit executes an adjusting operation which adjusts an amount of polishing of the glass substrate in compliance with a correlation between a first variable which changes in response to at least one of an electric power and an electric energy required for driving the motor and a second variable which changes in response to an amount of polishing of the glass substrate, and the correlation is derived in advance of the polishing of the glass substrate.

15. The polishing apparatus according to claim 14 , wherein the adjusting operation is executed during the driving of the motor based on at least one of the electric power and the electric energy.

16. A polishing apparatus according to claim 14 , wherein:

the first variable is an average electric power value as a value obtained by dividing the electric energy by a driving time of the motor;

the second variable is a multiplied value obtained by multiplying a number of sheets of the glass substrate by a polishing rate as a value given by dividing the amount of polishing of the glass substrate by the driving time of the motor;

the correlation is relational expressions among the amount of polishing of the glass substrate, the electric energy, and the driving time of the motor, which are specified by deriving coefficients of a recursion formula that represents a relation between the average electric power value and the multiplied value; and

the adjusting operation is a driving operation for driving the motor while substituting sequentially the electric energy and the driving time of the motor into the relational expressions during the driving of the motor until the amount of polishing of the glass substrate derived from the relational expressions reaches a predetermined target value.

17. The polishing apparatus according to claim 14 , wherein the glass substrate is a magnetic recording medium glass substrate.

18. The polishing apparatus according to claim 14 , wherein the polishing device comprises a platen and an abrasive pad positioned on the platen.