Objective lens driving device enabling speed-up of optical disk drive

• US 20050146999A1
• Filed: 08/30/2004
• Published: 07/07/2005
• Est. Priority Date: 11/26/2003
• Status: Abandoned Application

• Current Assignee: Mitsumi Electric Co., Ltd. (Minebea Mitsumi, Inc.)
• Original Assignee: Mitsumi Electric Co., Ltd. (Minebea Mitsumi, Inc.)
• Inventors: Yamada, Tsukasa
• Application Number:
  US10/929,852
• Publication Number:
  US 20050146999A1
• Time in Patent Office: Days
• US Class Current: 369/44.150
• CPC Class Codes: G11B 7/0933 Details of stationary parts
• CPC Class Codes: G11B 7/0935 Details of the moving parts
• CPC Class Codes: G11B 7/0956 to compensate for tilt, skew, warp or inclination of the disc, i.e. maintain the optical axis at right angles to the disc

Abstract

In an objective lens driving device having a lens holder which is movable and holds an objective lens, coil devices are disposed around the objective lens and held by the lens holder. Around the objective lens, main magnets are disposed for applying driving forces to the coil devices according to energization to the coil devices. Furthermore, each of auxiliary magnets are disposed between adjacent ones of the coil devices. The auxiliary magnets apply forces to the coil devices according to the energization to the coil devices for supplementing the driving forces.

Claims

1. An objective lens driving device comprising:

a lens holder being movable and holding an objective lens;

coil devices disposed around said objective lens and held by said lens holder;

main magnets disposed around said objective lens and applying driving forces to said coil devices according to energization to said coil devices; and

auxiliary magnets each disposed each between adjacent ones of said coil devices and applying forces to said coil devices according to the energization to said coil devices for supplementing said driving forces.

2. The objective lens driving device according to claim 1, wherein said main magnets and said auxiliary magnets are substantially separated, in terms of vibration, from said lens holder.

3. The objective lens driving device according to claim 1, wherein said objective lens has an optical axis extending in a first direction, said coil devices being disposed symmetrically at both sides of a plane which includes said optical axis and extends in a second direction perpendicular to said first direction.

4. The objective lens driving device according to claim 3, wherein said adjacent ones of said coil devices are arranged in said second direction.

5. An objective lens driving device according to claim 4, wherein said main magnets are respectively disposed on both outer sides, in said second direction, of said adjacent ones of said coil devices.

6. The objective lens driving device according to claim 5, wherein said main magnets are disposed symmetrically at the both sides of said plane, each main magnet at one of said both sides having a first polarity in said second direction, each main magnet at another of said both sides having a second polarity opposite to said first polarity.

7. The objective lens driving device according to claim 6, wherein said auxiliary magnets are disposed symmetrically at the both sides of said plane, an auxiliary magnet at the one of said both sides having said second polarity, an auxiliary magnet at the other of said both sides having said first polarity.

8. The objective lens driving device according to claim 3, wherein said main magnets and said auxiliary magnets are arranged so as to generate magnetic fields in directions that cancel each other and wherein those of said main magnets confronting each other in said second direction are arranged so as to have mutually opposite polarities and those of said auxiliary magnets confronting each other in said second direction are arranged so as to have mutually opposite polarities.

9. The objective lens driving device according to claim 1, further comprising:

a damper base;

a suspension member elastically supporting said lens holder with respect to said damper base; and

a damper member interposed between said damper base and said lens holder for separating, in terms of vibration, said lens holder from said damper base.

10. The objective lens driving device according to claim 9, further comprising a yoke base fixed to said damper base for magnetically coupling said main magnets and said auxiliary magnets to said coil devices.

11. The objective lens driving device according to claim 10, wherein said main magnets and said auxiliary magnets are fixed to said yoke base.

12. The objective lens driving device according to claim 10, wherein said yoke base comprises a plurality of yokes, each of said coil devices comprising a coil member receiving a corresponding one of said yokes fitted therein.

13. The objective lens driving device according to claim 12, wherein said coil member comprises a tilting coil and a focusing coil, and said coil device further comprises a tracking coil.

14. The objective lens driving device according to claim 9, wherein said suspension member comprises:

first elastic suspension wires disposed on both sides of said damper base and said lens holder; and

second elastic suspension wires disposed between said both sides of said damper base and said lens holder.

15. An optical pickup for irradiating a beam onto an optical medium and detecting a reflected beam reflected from said optical medium, said optical pickup including an objective lens driving device which comprises:

a damper base;

a suspension member elastically supporting said lens holder with respect to said damper base; and

a damper member interposed between said damper base and said lens holder for separating, in terms of vibration, said lens holder from said damper base, said damper base being movably supported.