Lens drive apparatus

• US 20070035860A1
• Filed: 08/10/2006
• Published: 02/15/2007
• Est. Priority Date: 08/10/2005
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Adachi, Yoshiki, Ezawa, Hiroshi
• Granted Patent: US 7,440,202 B2
• Time in Patent Office: Days
• US Class Current: 359/824
• CPC Class Codes: G01S 17/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S17/46
• CPC Class Codes: G01S 7/4814 of transmitters alone
• CPC Class Codes: G01S 7/4817 relating to scanning
• CPC Class Codes: G02B 26/0875 by means of one or more refracting elements
• CPC Class Codes: G02B 26/101 with both horizontal and vertical deflecting means, e.g. raster or XY scanners colour television using laser beams scanning a display screen H04N9/3129
• CPC Class Codes: G02B 7/023 permitting adjustment

Abstract

Shafts are fixed to a base and extend in a direction parallel to a center axis of a through hole of the base. Two yoke arrangements are installed to the shafts. A lens holder frame holds a lens, which has an optical axis parallel to the central axis of the through hole of the base. The lens holder frame is axially placed in a space between the two yoke arrangements and is swingably supported by a plurality of wire springs, which are fixed to the base. Drive coils are fixed to the lens holder frame and generate a drive force to move the lens holder frame.

Claims

1. A lens drive apparatus comprising:

a base that has a through hole, which penetrates through the base;

a plurality of shafts that are fixed to the base and extend in a direction generally parallel to a center axis of the through hole of the base;

two yoke arrangements, each of which holds a plurality of permanent magnets and surrounds the center axis of the through hole of the base, wherein the two yoke arrangements are supported by the plurality of shafts and are axially spaced from each other;

a lens holder frame that holds a lens, which has an optical axis generally parallel to the central axis of the through hole of the base, wherein the lens holder frame is axially placed in a space between the two yoke arrangements and is swingably supported by a plurality of wire springs, which are fixed to the base; and

a plurality of drive coils that are fixed to the lens holder frame and generate a drive force to move the lens holder frame.

2. The lens drive apparatus according to claim 1, further comprising at least one damper, which is positioned between the lens holder frame and at least one of the plurality of shafts.

3. The lens drive apparatus according to claim 1, further comprising a position sensor, which is installed to one of the two yoke arrangements to senses a position of the lens holder frame.

4. The lens drive apparatus according to claim 1, wherein each of the yoke arrangements includes one of:

a plurality of straight yoke pieces, which are connected together; and

a plurality of L-shaped yoke pieces, which are connected together.

5. The lens drive apparatus according to claim 1, further comprising a laser beam source, which provides a laser beam through the through hole of the base toward the lens, wherein the plurality of drive coils drive the lens holder frame in two dimensions to move the lens.

6. The lens drive apparatus according to claim 1, wherein at least one of the plurality of permanent magnets is opposed to a corresponding one of the plurality of drive coils and has an S-pole and an N-pole, which are provided in an axial end surface of the permanent magnet that axially opposes the corresponding drive coil.

7. The lens drive apparatus according to claim 1, further comprising silicone gel, which is held between at least one of the plurality of flexible wire springs and the base.

8. The lens drive apparatus according to claim 1, wherein at least one of the two yoke arrangements is formed as a square frame yoke.