Optical disk drive responsive to internal temperature change

• US 7,280,446 B2
• Filed: 09/28/2001
• Issued: 10/09/2007
• Est. Priority Date: 09/29/2000
• Status: Active Grant

• Current Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Inventors: Ishida, Hiroki, Tanaka, Sayoko, Suzuki, Yoshihisa, Noguchi, Hitoshi
• Primary Examiner(s): PSITOS, ARISTOTELIS
• Application Number:
  US09/964,874
• Publication Number:
  US 20020048237A1
• Time in Patent Office: 2,202 Days
• Field of Search: 369/53.18, 369/44.29
• US Class Current: 369/44.29
• CPC Class Codes: G11B 11/10576 with provision for moving the transducers for maintaining alignment or spacing relative to the carrier
• CPC Class Codes: G11B 11/10595 Control of operating function
• CPC Class Codes: G11B 7/094 Methods and circuits for servo offset compensation
• CPC Class Codes: G11B 7/0945 Methods for initialising servos, start-up sequences
• CPC Class Codes: G11B 7/126 Circuits, methods or arrangements for laser control or stabilisation

Abstract

There is provided an optical disk drive capable of appropriately effecting recording and reproducing operations without being affected by offset values and a laser output value, which are set at startup of the disk drive, even when changes have arisen in the internal temperature of the disk drive because of changes in ambient temperature. In an optical disk drive, a temperature sensor provided on a pickup measures a temperature. When changes in temperature are greater than a predetermined level, a focus offset value, a tracking offset value, and a value of laser output from the pickup are reset.

Claims

1. An optical disk drive comprising:

setting means for setting a focus offset value and/or a tracking offset value at startup of the optical disk drive;

first temperature measurement means for measuring an internal temperature of the optical disk drive at startup of the optical disk drive;

second temperature measurement means for measuring an internal temperature the optical disk drive after startup of the optical disk drive;

determination means for determining whether or not a difference between the temperature measured by the second temperature measurement means and the temperature measured by the first temperature measurement means has exceeded a predetermined level; and

resetting means for resetting the focus offset value and/or the tracking offset value set by the setting means when the determination means determines that the difference has exceeded the predetermined level.

2. The optical disk drive according to claim 1, wherein the second temperature measurement means measures a temperature at predetermined times;

the determination means determines whether or not a difference between a temperature most recently measured by the second temperature measurement means and an immediately preceding temperature measured by the second temperature measurement means has exceeded a predetermined level; and

resetting means resets a set focus offset value and/or a set tracking offset value when the determination means determines that the difference has exceeded the predetermined level.

3. An optical disk drive comprising:

setting means for setting a laser output value of a light-emitting section, a laser being output from the light-emitting section for recording and/or reproducing data on and/or from an optical disk, at startup of the optical disk drive;

first temperature measurement means for measuring an internal temperature of the optical disk drive at startup thereof;

second temperature measurement means for measuring an internal temperature of the optical disk drive after startup thereof;

determination means for determining whether or not a difference between the temperature measured by the second temperature measurement means and the temperature measured by the first temperature measurement means has exceeded a predetermined level; and

resetting means for resetting the laser output value set by the setting means when the determination means determines that the difference has exceeded the predetermined level.

4. The optical disk drive according to claim 3, wherein the second temperature measurement means measures a temperature at a predetermined time;

the determination means determines whether or not a difference between a temperature most recently measured by the second temperature measurement means and an immediately preceding temperature measured by the second temperature measurement means has exceeded a predetermined level; and

the resetting means resets a set laser output value when the determination means determines that the difference has exceeded the predetermined level.

5. An optical disk drive, comprising:

a temperature sensor for sensing an internal temperature of the optical disk drive; and

a controller for setting a laser output value of a light-emitting section, a laser being output from the light-emitting section for recording and/or reproducing data on and/or from an optical disk, wherein

the controller sets the laser output value at startup of the optical disk drive, determines whether or not a difference between a temperature measured by the temperature sensor at startup of the optical disk drive and a temperature measured by the temperature sensor after startup of the optical disk drive has exceeded a predetermined level, and resets the laser output value when the difference is determined to have exceeded the predetermined level.

6. The optical disk drive according to claim 5, wherein the controller measures the temperature detected by the temperature sensor at given times, determines whether or not a difference between a most-recently measured temperature and a measured temperature immediately preceding the most-recently measured temperature has exceeded a predetermined level, and resets a set laser output value when the difference is determined to have exceeded a predetermined value.