Micromachined mirror with stretchable restoring force member

• US 6,128,122 A
• Filed: 09/17/1999
• Issued: 10/03/2000
• Est. Priority Date: 09/18/1998
• Status: Expired due to Term

• Current Assignee: Seagate Technology LLC (Seagate Technology Holdings Plc)
• Original Assignee: Seagate Technology plc (Seagate Technology Holdings Plc)
• Inventors: Jerman, John H., Grade, John D., Drake, Joseph D.
• Primary Examiner(s): Phan, James
• Application Number:
  US09/398,259
• Time in Patent Office: 382 Days
• Field of Search: 359/198, 359/199, 359/212-214, 359/223, 359/224, 359/848, 359/871, 369/44.11, 369/44.14, 369/112
• US Class Current: 359/224.1
• CPC Class Codes: G02B 26/0816 by means of one or more reflecting elements
• CPC Class Codes: G02B 26/0833 the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD G02B26/0825 takes precedence; micromechanical devices in general B81B
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: G02B 26/085 the reflecting means being moved or deformed by electromagnetic means
• CPC Class Codes: G02B 6/3518 the reflective optical element being an intrinsic part of a MEMS device, i.e. fabricated together with the MEMS device MEMS devices in general B81B; manufacture of MEM devices in general B81C; micromechanical devices controlling the direction of light G02B26/0833
• CPC Class Codes: G02B 6/357 Electrostatic force electrostatic forces controlling reflecting elements in general G02B26/0841
• CPC Class Codes: G02B 6/3584 constructional details of an associated actuator having a MEMS construction, i.e. constructed using semiconductor technology such as etching MEMS per se B81B, B81C
• CPC Class Codes: G02B 7/1821 for rotating or oscillating mirrors
• CPC Class Codes: G11B 11/10532 Heads
• CPC Class Codes: G11B 11/10543 using optical beam of radiation
• CPC Class Codes: G11B 11/10563 Access of indexed parts
• CPC Class Codes: G11B 11/1058 Flying heads
• CPC Class Codes: G11B 7/08564 using galvanomirrors
• CPC Class Codes: G11B 7/08576 Swinging-arm positioners
• CPC Class Codes: G11B 7/122 Flying-type heads, e.g. analogous to Winchester type in magnetic recording
• CPC Class Codes: G11B 7/1362 Mirrors
• CPC Class Codes: G11B 7/1372 Lenses
• CPC Class Codes: G11B 7/1384 Fibre optics
• CPC Class Codes: H02N 1/006 of the gap-closing type H02N1/004 takes precedence
• CPC Class Codes: H02N 1/008 Laterally driven motors, e.g. of the comb-drive type

Abstract

A mirror assembly of micron dimensions for use in deflecting beam of light. The mirror assembly includes a planar base and a planar mirror spaced apart from the planar base and disposed generally parallel to the planar base. The planar mirror has first and second end portions and a longitudinal axis extending between the first and second end portions. First and second torsional members extend along the longitudinal axis and are connected to the respective first and second end portions for permitting the mirror to rock between first and second positions about the longitudinal axis relative to the planar base. The first and second torsional members are secured to the planar base. At least a portion of the mirror is made from a conductive material. First and second spaced-apart electrodes are carried by the planar base for driving the mirror between the first and second positions. A tether member extends transversely of the longitudinal axis and is secured to the first torsional member and to the planar base. The tether member regulates the rocking of the mirror.

Claims

1. A mirror assembly of micron dimensions for use in deflecting a beam of light comprising a planar base, a planar mirror spaced apart from the planar base and disposed generally parallel to the planar base, the planar mirror having first and second end portions and a longitudinal axis extending between the first and second end portions, first and second torsional members extending along the longitudinal axis and connected to the respective first and second end portions for permitting the mirror to rock between first and second positions about the longitudinal axis relative to the planar base, means for securing the first and second torsional members to the planar base, at least a portion of the mirror being of a conductive material, first and second spaced-apart electrodes carried by the planar base for driving the mirror between the first and second positions, a tether member extending transversely of the longitudinal axis and being secured to the first torsional member and means for securing the tether member to the planar base whereby the tether member regulates the rocking of the mirror.

2. The mirror assembly of claim 1 wherein the means for securing the first and second torsional members to the planar base and the means for securing the tether member to the planar base includes a frame member extending around the mirror, the first and second torsional members and the tether member being secured to the frame member and the frame member being spaced apart from and secured to the planar base.

3. The mirror assembly of claim 1 wherein the tether member has a length and at least a portion of the tether member is elastic along the length and wherein the first torsional member includes an elongate portion extending along the longitudinal axis and a substantially rigid flange portion extending transversely of the elongate portion and having an end spaced outwardly from the elongate portion, the tether member being secured to the end of the flange portion whereby the flange portion enhances stretching of the tether member during rocking of the mirror between the first and second positions.

4. A mirror assembly of micron dimensions for use in deflecting a beam of light comprising a planar base, a planar mirror spaced apart from the planar base and disposed generally parallel to the planar base, the planar mirror having first and second end portions and a longitudinal axis extending between the first and second end portions, first and second torsional members extending along the longitudinal axis and connected to the respective first and second end portions for permitting the mirror to rock between first and second positions about the longitudinal axis relative to the planar base, means for securing the first and second torsional members to the planar base, at least a portion of the mirror being of a conductive material, first and second spaced-apart electrodes carried by the planar base for driving the mirror between the first and second positions, first and second tether members extending transversely of the longitudinal axis and being secured to at least one of the first and second torsional members and means for securing the first and second tether members to the planar base whereby the first and second tether members regulate the rocking of the mirror.

5. The mirror assembly of claim 4 wherein each of the first and second tether members has a length and wherein at least a portion of each of the first and second tether members is elastic along the length.

6. The mirror assembly of claim 4 wherein the at least one of the first and second torsional members includes an elongate portion extending along the longitudinal axis and a substantially rigid flange portion extending transversely of the elongate portion and having a first end spaced outwardly from the elongate portion, the first tether member being secured to the first end of the flange portion whereby the flange portion enhances stretching of the first tether member during rocking of the mirror between the first and second positions.

7. The mirror assembly of claim 6 wherein the flange portion has a second end spaced outwardly from the elongate portion opposite of the first end, the second tether member being secured to the second end of the flange portion.

8. The mirror assembly of claim 6 wherein the flange portion extends perpendicularly of the elongate portion.

9. The mirror assembly of claim 4 wherein the at least one of the first and second torsional members includes an elongate portion extending along the longitudinal axis and a substantially rigid flange portion extending perpendicularly of the elongate portion and having first and second opposite ends spaced outwardly from the elongate portion, the first tether member being secured to the first end of the flange portion and the second tether member being secured to the second end of the flange portion whereby the flange portion enhances stretching of the first and second tether members during rocking of the mirror between the first and second positions.

10. The mirror assembly of claim 4 wherein the first and second tether members are secured to the first torsional member.

11. The mirror assembly of claim 10 wherein the first and second tether members extend along an axis extending transversely of the longitudinal axis.

12. The mirror assembly of claim 11 wherein the first and second tether members extend along an axis extending perpendicularly of the longitudinal axis.

13. The mirror assembly of claim 10 further comprising an additional set of first and second tether members, the additional set of first and second tether members being secured to the second torsional member.

14. A mirror assembly of micron dimensions for use in deflecting a beam of light comprising a planar base, a planar mirror spaced apart from the planar base and disposed generally parallel to the planar base, the planar mirror having first and second end portions and a longitudinal axis extending between the first and second end portions, at least a portion of the mirror being of a conductive material, at least one stretchable member extending transversely of the longitudinal axis and being secured to the mirror and means for securing the stretchable member to the planar base whereby the mirror is rockable between first and second positions about the longitudinal axis and the stretchable member provides a nonlinear restoring force to the mirror during rocking of the mirror.

15. The mirror assembly of claim 14 further comprising a least one electrode carried by the planar base for rocking the mirror about the longitudinal axis.

16. The mirror assembly of claim 14 further comprising first and second torsional members extending along the longitudinal axis and connected to the respective first and second end portions and means for securing the first and second torsional members to the planar base.

17. The mirror assembly of claim 16 wherein the stretchable member is secured to the mirror by means of one of the torsional members.

18. An optical data storage system comprising a support body, an optical disk rotatably mounted on the support body and having a planar storage surface, the storage surface having a plurality of concentrically disposed data tracks, an arm having proximal and distal extremities, the proximal extremity of the arm pivotably mounted on the support body so that the distal extremity of the arm can pivot between first and second positions relative to the storage surface, a flying optical head mounted on the distal extremity of the arm for aerodynamic suspension adjacent the storage surface during rotation of the disk on the support body, an optical light emitter and receiver emitting a laser beam carried by the arm and a mirror assembly of micron dimensions carried by the head for reflecting the laser beam between the optical light emitter and receiver and the storage surface of the disk to permit the optical recording and/or reading of information on the data tracks of the storage surface, the mirror assembly having a planar base and a planar mirror spaced apart from the planar base and disposed generally parallel to the planar base, the planar mirror having first and second end portions and a longitudinal axis extending between the first and second end portions, the mirror assembly including first and second torsional members extending along the longitudinal axis and connected to the first and second end portions and means for securing the first and second torsional members to the planar base whereby the mirror is rockable between first and second positions about the longitudinal axis relative to the planar base, at least a portion of the mirror being of a conductive material, the mirror assembly having first and second spaced-apart electrodes carried by the planar base for driving the mirror between the first and second positions, the mirror assembly being provided with first and second tether members extending transversely of the longitudinal axis and being secured to at least one of the first and second torsional members and means for securing the first and second tether members to the planar base whereby the first and second tether members regulate the rocking of the mirror.

19. The data storage system of claim 18 wherein the first torsional member includes an elongate portion extending along the longitudinal axis and a substantially rigid flange portion extending perpendicularly of the elongate portion and having first and second opposite ends spaced outwardly from the elongate portion, the first tether member being secured to the first end of the flange portion and the second tether member being secured to the second end of the flange portion whereby the flange portion enhances stretching of the first and second tether members during rocking of the mirror between the first and second positions.

20. The data storage system of claim 19 wherein the first and second tether members are secured to the first torsional member, further comprising an additional set of first and second tether members, the additional set of first and second tether members being secured to the second torsional member.