Rotation detecting system for galvano mirror

• US 6,327,066 B2
• Filed: 03/16/2001
• Issued: 12/04/2001
• Est. Priority Date: 06/27/1997
• Status: Expired due to Fees

• Current Assignee: Asahi Kogaku Kogyo Kabushiki Kaisha
• Original Assignee: Asahi Kogaku Kogyo Kabushiki Kaisha
• Inventors: Takishima, Suguru, Nakagishi, Toshio
• Primary Examiner(s): Schuberg, Darren
• Assistant Examiner(s): ASSAF, FAYEZ G
• Application Number:
  US09/809,097
• Publication Number:
  US 20010010588A1
• Time in Patent Office: 263 Days
• Field of Search: 359/196, 359/197, 359/198, 359/213, 359/214, 250/236, 250/230, 250/234, 369/44.17, 369/44.21, 310/66, 310/75.R
• US Class Current: 359/198.1
• CPC Class Codes: G11B 7/08564 using galvanomirrors
• CPC Class Codes: G11B 7/08576 Swinging-arm positioners

Abstract

A galvano mirror system includes (1) a galvano mirror, (2) a mirror holder having a front portion to which the galvano mirror is mounted and a rear portion opposing to the front portion, (3) a stator which rotatably supports the mirror holder, (4) first and second reflecting surfaces provided to the rear portion of the mirror holder, and (5) first and second photo sensors provided to the stator. Each photo sensor includes a light-emitting device and a light-receiving device. A controller of the galvano mirror system detects the rotational position of the mirror holder according to on a difference in outputs of the light-receiving devices of the first and second photo sensors.

Claims

1. A galvano mirror system, comprising:

a galvano mirror having a mirror surface that reflects light for at least one of data reading and data writing;

a mirror holder having a front portion to which said galvano mirror is mounted, and a rear portion opposing said front portion;

a stator that rotatably supports the said holder;

a first reflecting surface;

a second reflecting surface, said first reflecting surface and said second reflecting surface being associated with said rear portion of said mirror holder;

a first photo sensor;

a second photo sensor, said first photo sensor and said second photo sensor being associated with said stator, such that said first photo sensor faces said first reflecting surface and said second photo sensor faces said second reflecting surface, said first photo sensor and said second photo sensor each comprising a light-emitting device and a light-receiving device, said light-emitting device and said light-receiving device of said respective first photo sensor and second photo sensor being disposed in a certain direction perpendicular to a rotation axis of said mirror holder, said first reflecting surface and said second reflecting surfaces being disposed in said certain direction, said first photo sensor and said second photo sensor being fixed to a sensor holder mounted to said stator, a position of said sensor holder, with respect to said mirror holder, being adjusted in said certain direction;

a controller that deflects a rotation of said mirror holder according to a difference in output between said light-receiving device of said first photo sensor and said light-receiving device of said second photo sensor; and

a guide member associated with one of a base member and said sensor holder, said sensor holder being arranged to move substantially parallel to said reflection surface of said mirror holder along said guide member to correct said difference in output between said light-receiving device of said first photo sensor and said light-receiving device of said second photo sensor.

2. The galvano mirror system of claim 1, said sensor holder having at least one contact surface that contacts said stator.

3. The galvano mirror system of claim 2, said light-emitting device and said light-receiving device of said first photo sensor, and said light-emitting device and said light-receiving device of said second photo sensor, being aligned in a predetermined plane parallel to said at least contact surface.

4. The galvano mirror system of claim 3, wherein an original position of said mirror holder is defined when said first reflecting surface and said second reflecting surface are parallel to said plane.

5. A galvano mirror system, comprising:

a galvano mirror having a mirror surface that reflects light for at least one of data reading and data writing;

a mirror holder having a front portion to which said galvano mirror is mounted, and a rear portion opposing said front portion;

a stator that rotatably supports said holder;

a first reflecting surface;

a second reflecting surface, said first reflecting surface and said second reflecting surface being associated with said rear portion of said mirror holder;

a first photo sensor;

a second photo sensor, said first photo sensor and said second photo sensor being associated with said stator, such that said first photo sensor faces said first reflecting surface and said second photo sensor faces said second reflecting surface, said first photo sensor and said second photo sensor each comprising a light-emitting device and a light-receiving device, said light-emitting device and said light-receiving device of said respective first photo sensor and second photo sensor being disposed in a certain direction perpendicular to a rotation axis of said mirror holder, said first reflecting surface and said second reflecting surfaces being disposed in said certain direction;

a controller that deflects a rotation of said mirror holder according to a difference in output between said light-receiving device of said first photo sensor and said light-receiving device of said second photo sensor, wherein said light-receiving device of said first photo sensor and said light-receiving device of said second photo sensor are disposed between said light-emitting device of said first photo sensor and said light-emitting device of said second photo sensor so that external light does not enter said light-receiving device of said first photo sensor and said second light-receiving device of said second photo sensor.

6. The galvano mirror system of claim 5, further comprising a sensor holder, said first photo sensor and said second photo sensor being fixed to said sensor holder.

7. The galvano mirror system of claim 6, wherein said sensor holder contacts said stator.

8. The galvano mirror system of claim 7, wherein said sensor holder moves substantially parallel to a reflection surface of said mirror holder to correct for said difference in output between said light-receiving device of said first photo sensor and said light-receiving device of said second photo sensor.

9. A galvano mirror system, comprising:

a galvano mirror having a front surface that reflects a laser beam for at least one of data reading and writing, and a rear surface opposing said front surface;

a mirror holder having a front portion to which said galvano mirror is mounted, a rear portion of said mirror holder opposing said front portion;

a stator that rotatably supports said mirror holder;

a reflecting surface associated with said rear surface of said galvano mirror;

a photo sensor associated with said stator so that said photo sensor faces said reflecting surface, said photo sensor being fixed to a sensor holder mounted to said stator, said photo sensor comprising a light-emitting device and two light-receiving devices aligned on a same plane, said two light-receiving devices being laterally disposed and accommodated in a package, with said light-emitting device being disposed above said package;

a controller that detects a rotation of said mirror holder in accordance with a difference in output between said two light-receiving devices; and

a guide member associated with one of a base member and said sensor holder, said sensor holder being arranged to move substantially parallel to said reflection surface of said mirror holder along said guide member to correct said difference in output between said light-receiving devices.

10. The galvano mirror system of claim 9, wherein said two light-receiving devices are disposed in a certain direction perpendicular to a rotational axis.

11. The galvano mirror system of claim 10, wherein said photo sensor is fixed to a sensor holder mounted to said stator.

12. The galvano mirror system of claim 11, wherein said sensor holder is adjusted in said certain direction.

13. The galvano mirror system of claim 12, wherein said sensor holder includes a contact surface that contacts said stator.

14. The galvano mirror system of claim 13, wherein said light-emitting device and said two light-receiving devices are aligned on a plane parallel to said contact surface.