Microactuator, magnetic head device, and magnetic recording apparatus

• US 6,424,504 B1
• Filed: 06/04/1999
• Issued: 07/23/2002
• Est. Priority Date: 06/16/1998
• Status: Expired due to Fees

• Current Assignee: ALPS Electric Company Limited (Alps Alpine Co., Ltd.), Masayoshi Esashi
• Original Assignee: ALPS Electric Company Limited (Alps Alpine Co., Ltd.), Masayoshi Esashi
• Inventors: Esashi, Masayoshi, Abe, Munemitsu
• Primary Examiner(s): KLIMOWICZ, WILLIAM JOSEPH
• Application Number:
  US09/326,195
• Time in Patent Office: 1,145 Days
• Field of Search: 360/294.4, 360/294.3, 310/309, 310/40.MM, 310/22, 310/29, 310/313.B, 310/313.C, 310/365, 310/366
• US Class Current: 360/294.4
• CPC Class Codes: B81B 2203/0136 Comb structures
• CPC Class Codes: B81B 2203/051 Translation according to an axis parallel to the substrate
• CPC Class Codes: B81B 3/0051 For defining the movement, i.e. structures that guide or limit the movement of an element mechanical arrangements for preventing or damping vibration or shock H01H3/60
• CPC Class Codes: G11B 21/20 while the head is in operative position but stationary or permitting minor movements to follow irregularities in surface of record carrier
• CPC Class Codes: G11B 5/5552 using fine positioning means for track acquisition separate from the coarse (e.g. track changing) positioning means
• CPC Class Codes: G11B 5/5556 with track following after a "seek"
• CPC Class Codes: H02N 1/008 Laterally driven motors, e.g. of the comb-drive type

Abstract

In a microactuator, a fixed substrate and a movable substrate are placed to be spaced opposed to each other. Between these substrates, a plurality of actuators are arranged to provide different moving distances. The actuators include comb-like movable electrodes formed on the movable substrate, and fixed electrodes formed on the fixed substrate, and having a plurality of teeth that extend outside the leading ends of the teeth of the movable electrodes in an undriven state. The movable substrate is allowed to move so that the leading ends of the teeth of the movable electrodes reach the outer ends of the teeth of the fixed electrodes. The portions of the fixed electrode teeth, which extend outside the movable electrode teeth, are different in length among the actuators.

Claims

1. A microactuator wherein opposing substrates are spaced so as to move relative to each other, and a plurality of actuators for providing different distances of relative motion between said substrates are arranged between said substrates at predetermined intervals in the direction of relative motion between said substrates, and wherein the plurality of actuators are disposed so that the distances of relative motion between said substrates gradually increase in the one direction of relative motion between said substrates, but gradually decrease in a direction opposite to the one direction of relative motion,

further wherein each of said actuators comprises a plurality of first comb-like electrodes formed on the opposing surface of a first substrate that is one of said substrates, and having a plurality of parallel teeth which have the same length and are aligned at the leading ends thereof;

and a second electrode formed on the opposing face of a second substrate that is the other substrate, and having a plurality of parallel teeth aligned at the outer ends thereof so as to be placed between the adjoining teeth of each of said plurality of first electrodes and to extend outward from similar locations from the inner back side of lines which connect the leading ends of said teeth of each of said first electrodes in an undriven state, the outer ends of extending portions of said plurality of teeth being moved to the leading ends of said teeth of said first electrodes in a driven state in order to cause said substrates to move relative to each other, wherein said outwardly extending portions of said second electrode teeth are different in length among said actuators, and wherein the lengths of said second electrode teeth of said plurality of actuators gradually vary, respectively, in a direction in which said plurality of actuators are disposed so that the distances of relative motion between said substrates gradually increase in the one direction of relative motion between said substrates, but gradually decrease in a direction opposite to the one direction of relative motion.

2. A magnetic head device comprising a microactuator claimed in claim 1.

3. A magnetic recording apparatus comprising a magnetic head device claimed in claim 2.

4. A microactuator according to claim 1, wherein, in the plurality of actuators, the leading surfaces of the plurality of teeth of the first electrodes, and an approaching and separating face are formed so as not to be parallel to each other, with the approaching and separating face opposing the leading ends of the teeth of the first electrodes and approaching and separating while opposing the leading surface of the plurality of teeth of the first electrodes at a connection portion of the second electrode where the plurality of teeth of the second electrode are consecutively formed.

5. A microactuator according to claim 4, wherein the leading ends of the plurality of teeth of the first electrodes have planar convex shapes which taper off towards the leading ends, and wherein the approaching and separating face has a planar convex shape which protrudes and tapers off towards the leading ends of the first electrodes, with the approaching and separating face approaching and separating while opposing the leading surfaces of the plurality of teeth of the first electrodes at the connection portion of the second electrode.

6. A microactuator according to claim 4, wherein the leading ends of the plurality of teeth of the first electrodes have planar concave shapes which broaden towards the leading ends, and wherein the approaching and separating face is a flat face, with the approaching and separating face approaching and separating while opposing the leading surfaces of the plurality of teeth of the first electrodes at the connection portion of the second electrode.

7. A microactuator according to claim 4, wherein the leading ends of the plurality of teeth of the first electrodes have planar convex shapes which taper off towards the leading ends, and wherein the approaching and separating face is a flat face, with the approaching and separating face approaching and separating while opposing the leading surfaces of the plurality of teeth of the first electrodes at the connection portion of the second electrode.

8. A microactuator wherein opposing substrates are spaced so as to move relative to each other, and a plurality of actuators for providing different distances of relative motion between said substrates in the same direction of movement are arranged between said substrates at predetermined intervals in the direction of relative motion between said substrates,

further wherein each of said actuators for providing different distances of relative motion between said substrates in the same direction of movement comprises a first comb-like electrode formed on the opposing face of a first substrate that is one of said substrates, and having a plurality of parallel teeth aligned at the leading ends thereof;

and a second electrode formed on the opposing face of a second substrate that is the other substrate, and having a plurality of parallel teeth at the outer ends thereof so as to be placed between the adjoining teeth of said first electrodes and to extend outside the leading ends of said teeth of said first electrode in an undriven state, the outer ends of extending portions of said plurality of teeth being moved to the leading ends of said teeth of said first electrode in a driven state in order to cause said substrates to move relative to each other, and wherein said outside extending portions of said second electrode teeth are different in length among said actuators.