Focus control method, and optical disk unit with focus offset correction
AssigneeFujitsu Limited
InventorsToru Ikeda, Akira Minami
Life of this patent
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Abstract
A focus control method controls a focus servo system which controls a focus of a light irradiated on an optical disk in an optical disk unit which has a plurality of operation modes. The focus control method includes the steps of (a) reading focus offset information from a memory which prestores focus offset information depending on the operation modes of the optical disk unit, and (b) controlling the focus with respect to the optical disk by supplying the focus offset information read in the step (a) to the focus servo system when the operation mode of the optical disk unit is switched from one mode to another.
Claims26
A focus control method which controls a focus servo system for controlling a focus of a light irradiated on an optical disk in an optical disk unit which has a plurality of operation modes, said focus control method comprising the steps of:
- (a) reading focus offset information from a memory in relation to an operation mode selected, said memory storing plural focus offset information for correcting a focus error generated immediately after the operation mode is switched from one operation to another;
- and
- (b) controlling the focus with respect to the optical disk by supplying the focus offset information read in said step (a) to the focus servo system when the operation mode of the optical disk unit is switched from one operation mode to another.
An optical disk unit comprising:
- a focus servo system controlling a focus of a light irradiated on an optical disk;
- a memory for storing plural focus offset information for correcting a focus error which is generated immediately after an operation mode of the optical disk unit is switched from one operation mode to another, wherein selected said focus offset information is associated with a selected one of plural operation modes;
- and
- a controller correcting a focus error with respect to the optical disk by supplying a focus offset value which is based on the focus offset information read from said memory to said focus servo system at a time when the operation mode of the optical disk unit is switched from the one operation mode to another.
A focus control method which controls a focus servo system for controlling a focus of a light irradiated on an optical disk in an optical disk unit which has a plurality of operation modes, said focus control method comprising the steps of:
- (a) reading focus offset information from a memory which prestores focus offset information for correcting a focus error, wherein said focus offset information is read from said memory depending on an operation mode selected, wherein first focus offset information determined as an average read FES value is used during a read mode and second focus offset information determined as a difference between said average read FES value and an average switching FES value is used during a write mode;
- and
- (b) controlling the focus with respect to the optical disk by supplying the focus offset information read in said step (a) to the focus servo system when the operation mode of the optical disk unit is switched from one mode to another.
An optical disk unit comprising:
- a focus servo system controlling a focus of a light irradiated on an optical disk;
- a memory storing focus offset information for correcting a focus error, wherein said focus offset information depends on an operation mode selected, wherein first focus offset information determined as an average read FES value is used during a read mode and second focus offset information determined as a difference between said average read FES value and an average switching FES value is used during a write mode;
- and
- a controller correcting a focus error with respect to the optical disk by supplying a focus offset value which is based on the focus offset information read from said memory to said focus servo system at a time when the operation mode of the optical disk unit is switched from one mode to another.
A focus control method which controls a focus servo system for controlling a focus of a light irradiated on an optical disk in an optical disk unit which has a plurality of operation modes, said focus control method comprising the steps of:
- (a) reading focus offset information from a memory in relation to an operation mode selected, said memory storing plural focus offset information for correcting a focus error generated immediately after the operation mode is switched from one operation mode to another;
- (b) controlling the focus with respect to the optical disk by supplying the focus offset information read in said step (a) to the focus servo system when the operation mode of the optical disk unit is switched from the one operation mode to another;
- and
- (c) detecting a temperature within the optical disk unit at an arbitrary timing,
- said step (b) supplying to the focus servo system focus offset information corresponding to the temperature detected in said step (c).
An optical disk unit comprising:
- a focus system controlling a focus of a light irradiated on an optical disk;
- a memory storing plural focus offset information for correcting a focus error which is generated immediately after an operation mode of the optical disk unit is switched from one operation mode to another, wherein selected said focus offset information is associated with a selected one of plural operation modes;
- a controller correcting a focus error with respect to the optical disk by supplying a focus offset value which is based on the focus offset information read from said memory to said focus servo system at a time when the operation mode of the optical disk unit is switched from the one operation mode to another;
- and
- a detector detecting a temperature within the optical disk unit at an arbitrary timing,
- said controller supplying a focus offset value corresponding to the temperature detected by said detector to said focus servo system.
Dependencies are inferred from the claim text.