Automatic focusing mechanism

• US 20080062301A1
• Filed: 11/08/2007
• Published: 03/13/2008
• Est. Priority Date: 05/11/2005
• Status: Active Grant

• Current Assignee: China Mobile Internet Technologies Incorporated (Central People's Government of The People's Republic of China)
• Original Assignee: Beijing Huaqi Digital Technology Lab Company Limited
• Inventors: ZHOU, Chao-hui
• Granted Patent: US 8,040,426 B2
• Time in Patent Office: Days
• US Class Current: 348/345
• CPC Class Codes: G02B 7/005 Motorised alignment
• CPC Class Codes: G02B 7/08 adapted to co-operate with a remote control mechanism
• CPC Class Codes: G03B 13/36 Autofocus systems
• CPC Class Codes: G03B 3/04 adjusting position of image plane without moving lens
• CPC Class Codes: G03B 3/10 Power-operated focusing
• CPC Class Codes: H04N 23/54 Mounting of pick-up tubes, electronic image sensors, deviation or focusing coils
• CPC Class Codes: H04N 23/67 Focus control based on electronic image sensor signals

Abstract

An automatic focusing mechanism comprises a plurality of lenses and an image sensor disposed along an optical axis, an electromagnetic driving device for generating an electromagnetic force to drive the image sensor to move along the optical axis, and a position-limited device for limiting the movement of the image sensor along the optical axis. The image sensor is driven by the electromagnetic force and moved along the optical axis, and the distance between the lenses and the image sensor is properly adjusted, thereby realizing automatic focusing.

Claims

1. An automatic focusing mechanism comprising:

a lens group arranged along an optical axis;

an image sensor arranged along the optical axis;

an electromagnetic driver for inducing an electromagnetic force to drive the image sensor to move along the optical axis; and

a spacing restrictor for limiting an movement of the image sensor along the optical axis.

2. The apparatus as claimed in claim 1, wherein the electromagnetic driver comprises a magnet having a fixed position relative to the lens group and a drive coil being firmly connected to the image sensor.

3. The apparatus as claimed in claim 2, further comprising a PCB substrate for assembling the image sensor.

4. The apparatus as claimed in claim 3, wherein the spacing restrictor is an elastomer member, one end of the elastomer member is connected to the PCB substrate and the other end of the elastomer member has a fixed position relative to the lens group.

5. The apparatus as claimed claim 4, wherein the elastomer member comprises a polyester film member, a nylon film member, a rubber film member or a polyimide film member.

6. The apparatus as claimed claim 4, wherein the elastomer member includes a flexible PCB, the one end of the flexible PCB being connected to the image sensor is provided for transmitting electrical signals of the image sensor.

7. The apparatus as claimed claim 6, wherein the one end of the flexible PCB being connected to the image sensor is provided for electrically connecting with the drive coil so as to provide the drive coil with a driving current.

8. The apparatus as claimed claim 4, wherein the center of the image sensor, the barycenter of an integration combing the image sensor with the PCB base plate, the circle center of the drive coil are all located on the optical axis.

9. The apparatus as claimed in claim 4, wherein the drive coil is firmly fixed on one surface of the PCB substrate on the opposite surface of which the image sensor is assembled, the magnet is columned, and the drive coil movably encloses around the magnet.

10. The apparatus as claimed in claim 6, wherein the flexible PCB is bent into a V-shape, a W-shape or a multi-pleat shape.