Micromachined sensors

• US 7,814,794 B2
• Filed: 09/07/2007
• Issued: 10/19/2010
• Est. Priority Date: 09/07/2007
• Status: Expired due to Fees

• Current Assignee: PixArt Imaging Incorporated
• Original Assignee: PixArt Imaging Incorporated
• Inventors: WANG, Chuan Wei
• Primary Examiner(s): CHAPMAN JR, JOHN E
• Application Number:
  US11/851,903
• Publication Number:
  US 20090064784A1
• Time in Patent Office: 1,138 Days
• Field of Search: 735/143.2, 361/280
• US Class Current: 73/514.32
• CPC Class Codes: G01P 15/125 by capacitive pick-up
• CPC Class Codes: G01P 2015/0814 for translational movement of the mass, e.g. shuttle type

Abstract

The present invention provides a micromachined sensor. The micromachined sensor includes a proof mass movable with respect to a substrate. The proof mass includes a first portion, a second portion separated from the first portion and a third portion connecting the first portion to the second portion. A frame is positioned on the substrate and encloses the proof mass. A plurality of springs connects the proof mass to the frame. A plurality of first and second electrodes extends from the frame. A plurality of third electrodes extends from the first portion of the proof mass and is interleaved with the first electrodes. A plurality of fourth electrodes extends from the second portion of the proof mass and is interleaved with the second electrodes. A first support beam extends from the frame to the area between the first and second portions of the proof mass. A plurality of seventh and eighth electrodes extends from the first support beam. A plurality of fifth electrodes extends from the first portion of the proof mass and is interleaved with the seventh electrodes. A plurality of sixth electrodes extends from the second portion of the proof mass and is interleaved with the eighth electrodes.

Claims

1. A micromachined sensor, comprising:

a substrate;

a proof mass movable with respect to the substrate, the proof mass having a first portion, a second portion separated from the first portion and a third portion connecting the first portion to the second portion;

a frame positioned on the substrate and enclosing the proof mass;

a plurality of springs connecting the proof mass to the frame;

a plurality of first electrodes extending from the frame;

a plurality of second electrodes extending from the frame;

a plurality of third electrodes extending from the first portion of the proof mass and interleaved with the first electrodes;

a plurality of fourth electrodes extending from the second portion of the proof mass and interleaved with the second electrodes;

a first support beam extending from the frame to the area between the first and second portions of the proof mass;

a plurality of seventh electrodes extending from the first support beam;

a plurality of eighth electrodes extending from the first support beam;

a plurality of fifth electrodes extending from the first portion of the proof mass and interleaved with the seventh electrodes; and

a plurality of sixth electrodes extending from the second portion of the proof mass and interleaved with the eighth electrodes.

2. The micromachined sensor as claimed in claim 1, further comprising:

a second support beam extending from the frame to the area between the first and second portions of the proof mass, wherein the first and second support beams are in alignment with each other and separated by the third portion of the proof mass;

a plurality of ninth electrodes extending from the second support beam and interleaved with the fifth electrodes; and

a plurality of tenth electrodes extending from the second support beam and interleaved with the sixth electrodes.

3. The micromachined sensor as claimed in claim 2, wherein the frame has two opposing sides, the micromachined sensor further comprising:

two first anchors connected to the opposing sides of the frame respectively and rigidly coupled to the substrate, wherein the first anchors are in alignment with the first and second support beams.

4. The micromachined sensor as claimed in claim 3, further comprising:

a second anchor connected to the end of the first support beam and rigidly coupled to the substrate; and

a third anchor connected to the end of the second support beam and rigidly coupled to the substrate.

5. The micromachined sensor as claimed in claim 2, further comprising:

a first anchor connected to the end of the first support beam and rigidly coupled to the substrate; and

a second anchor connected to the end of the second support beam and rigidly coupled to the substrate.

6. The micromachined sensor as claimed in claim 1, wherein the frame has two opposing sides, the micromachined sensor further comprising:

two anchors connected to the opposing sides of the frame respectively and rigidly coupled to the substrate, wherein the anchors are in alignment with the first support beam.

7. The micromachined sensor as claimed in claim 1, further comprising:

a first anchor connected to the end of the first support beam and rigidly coupled to the substrate.

8. A micromachined sensor, comprising:

a substrate;

a proof mass movable with respect to the substrate, the proof mass having a first portion, a second portion, a third portion separated from the first and second portions, a fourth portion connecting the first portion to the third portion and a fifth portion connecting the second portion to the third portion;

a frame positioned on the substrate and enclosing the proof mass;

a plurality of springs connecting the proof mass to the frame;

a plurality of first electrodes extending from the frame;

a plurality of twelfth electrodes extending from the frame;

a plurality of second electrodes extending from the first portion of the proof mass and interleaved with the first electrodes;

a plurality of eleventh electrodes extending from the second portion of the proof mass and interleaved with the twelfth electrodes;

a plurality of third electrodes extending from the first portion of the proof mass;

a plurality of tenth electrodes extending from the second portion of the proof mass;

a plurality of sixth electrodes extending from the third portion of the proof mass;

a plurality of seventh electrodes extending from the third portion of the proof mass;

a first support beam extending from the frame to the area between the first and third portions of the proof mass;

a second support beam extending from the frame to the area between the second and third portions of the proof mass;

a plurality of fourth electrodes extending from the first support beam and interleaved with the third electrodes;

a plurality of fifth electrodes extending from the first support beam and interleaved with the sixth electrodes;

a plurality of eighth electrodes extending from the second support beam and interleaved with the seventh electrodes; and

a plurality of ninth electrodes extending from the second support beam and interleaved with the tenth electrodes.

9. The micromachined sensor as claimed in claim 8, further comprising:

a third support beam extending from the frame to the area between the first and third portions of the proof mass, wherein the first and third support beams are in alignment with each other and separated by the fourth portion of the proof mass;

a fourth support beam extending from the frame to the area between the second and third portions of the proof mass, wherein the second and fourth support beams are in alignment with each other and separated by the fifth portion of the proof mass;

a plurality of thirteenth electrodes extending from the third support beam and interleaved with the third electrodes;

a plurality of fourteenth electrodes extending from the third support beam and interleaved with the sixth electrodes;

a plurality of fifteenth electrodes extending from the fourth support beam and interleaved with the seventh electrodes; and

a plurality of sixteenth electrodes extending from the fourth support beam and interleaved with the tenth electrodes.

10. The micromachined sensor as claimed in claim 9, wherein the frame has two opposing sides, the micromachined sensor further comprising:

two first anchors connected to the opposing sides of the frame respectively and rigidly coupled to the substrate, wherein the first anchors are in alignment with the third portion of the proof mass.

11. The micromachined sensor as claimed in claim 10, further comprising:

a second anchor connected to the end of the first support beam and rigidly coupled to the substrate;

a third anchor connected to the end of the second support beam and rigidly coupled to the substrate;

a fourth anchor connected to the end of the third support beam and rigidly coupled to the substrate; and

a fifth anchor connected to the end of the fourth support beam and rigidly coupled to the substrate.

12. The micromachined sensor as claimed in claim 9, further comprising:

a first anchor connected to the end of the first support beam and rigidly coupled to the substrate;

a second anchor connected to the end of the second support beam and rigidly coupled to the substrate;

a third anchor connected to the end of the third support beam and rigidly coupled to the substrate; and

a fourth anchor connected to the end of the fourth support beam and rigidly coupled to the substrate.

13. The micromachined sensor as claimed in claim 8, wherein the frame has two opposing sides, the micromachined sensor further comprising:

two anchors connected to the opposing sides of the frame respectively and rigidly coupled to the substrate, wherein the fifth anchors are in alignment with the third portion of the proof mass.

14. The micromachined sensor as claimed in claim 8, further comprising:

a first anchor connected to the end of the first support beam and rigidly coupled to the substrate; and

a second anchor connected to the end of the second support beam and rigidly coupled to the substrate.