Micro-electro-mechanical system device and micro-electro-mechanical system compensation structure

• US 9,783,409 B2
• Filed: 09/28/2014
• Issued: 10/10/2017
• Est. Priority Date: 10/03/2013
• Status: Active Grant

• Current Assignee: PixArt Imaging Incorporated
• Original Assignee: PixArt Imaging Incorporated
• Inventors: Tsai, Ming-Han, Sun, Chih-Ming, Hsu, Hsin-Hui
• Primary Examiner(s): Koval, Melissa
• Assistant Examiner(s): NGUYEN, TRUNG Q
• Application Number:
  US14/499,200
• Publication Number:
  US 20150097586A1
• Time in Patent Office: 1,108 Days
• Field of Search: 324686, 324684, 324500, 324600, 324200, 32420712, 32475411, 324219-242, 32475017, 32475428, 324658, 324 7666, 438 48- 53, 257414-417
• CPC Class Codes: B81B 3/0086 Electrical characteristics, e.g. reducing driving voltage, improving resistance to peak voltage

Abstract

This invention provides a MEMS device, including: a mass structure having at least one anchor; at least one flexible structure connected with the mass structure at the at least one anchor; a plurality of top electrodes located above the mass structure and forming a top capacitor circuit with the mass structure; and a plurality of bottom electrodes located under the mass structure and forming a bottom capacitor circuit with the mass structure. The projections of the plural top electrodes on the mass structure along a normal direction of the mass structure are located at opposite sides of the anchor, and the projections of the plural bottom electrodes on the mass structure along a normal direction of the mass structure are located at opposite sides of the anchor. This invention also provides a MEMS compensation structure.

Claims

1. A MEMS device, comprising:

a mass structure, including at least one anchor;

at least one flexible structure connected with the mass structure at the at least one anchor;

a plurality of top electrodes, located above the mass structure to form a top capacitor circuit with the mass structure;

a plurality of bottom electrodes, located under the mass structure to form a bottom capacitor circuit with the mass structure;

a compensation mass structure;

a plurality of top compensation electrodes, located above the compensation mass structure and forming a top compensation capacitor circuit with the compensation mass structure, wherein the top compensation electrodes are coupled to the bottom electrodes; and

a plurality of bottom compensation electrodes, located under the compensation mass structure and forming a bottom compensation capacitor circuit with the compensation mass structure, wherein the bottom compensation electrodes are coupled to the top electrodes;

wherein projections of the top electrodes on the mass structure along a normal direction of the mass structure are located at opposite sides of the anchor, and projections of the plural bottom electrodes on the mass structure along a normal direction of the mass structure are located at opposite sides of the anchor.

2. The MEMS device of claim 1, comprising a plurality of anchors and a plurality of flexible structures, wherein the projections of the top electrodes on the mass structure along the normal direction of the mass structure are located at opposite sides of each anchor, and the projections of the bottom electrodes on the mass structure along the normal direction of the mass structure are located at opposite sides of each anchor.

3. The MEMS device of claim 1, wherein the top capacitor circuit comprises a plurality of local top capacitors each of which is formed by the mass structure and one of the top electrodes;

when the mass structure is deformed, a portion of the local top capacitors increase their capacitances because of the deformation of the mass structure, and another portion of the local top capacitors decrease their capacitances because of the deformation of the mass structure.

4. The MEMS device of claim 1, wherein the bottom capacitor circuit comprises a plurality of local bottom capacitors each of which is formed by the mass structure and one of the bottom electrodes;

when the mass structure is deformed, a portion of the local top capacitors increase their capacitances because of the deformation of the mass structure, and another portion of the local top capacitors decrease their capacitances because of the deformation of the mass structure.

5. The MEMS device of claim 1, wherein the compensation mass structure is fixed and does not move relatively with respect to the top compensation electrodes and the bottom compensation electrodes.

6. The MEMS device of claim 1, wherein the compensation mass structure and the mass structure are connected to a same voltage level;

the top compensation electrodes and the bottom electrodes are connected to another same voltage level; and

the bottom compensation electrodes and the top electrodes are connected to yet another same voltage level, whereby the top capacitor and the bottom compensation capacitor form a parallel capacitor circuit, and the bottom capacitor and the top compensation capacitor form another parallel capacitor circuit.

7. A MEMS compensation structure for use in a MEMS device which includes a top capacitor circuit located at an upper elevation level along a vertical direction and a bottom capacitor circuit located at a lower elevation level along the vertical direction, the MEMS compensation structure comprising:

a compensation mass structure;

a plurality of top compensation electrodes, forming a top compensation capacitor circuit with the compensation mass structure, wherein the top compensation capacitor circuit and the bottom capacitor circuit are connected in parallel; and

a plurality of bottom compensation electrodes, forming a bottom compensation capacitor circuit with the compensation mass structure, wherein the bottom compensation capacitor circuit and the top capacitor circuit are connected in parallel;

wherein the top capacitor circuit is formed by a mass structure and a plurality of top electrodes, and the bottom capacitor circuit is formed by the mass structure and a plurality of bottom electrodes;

wherein the numbers of the top compensation electrodes and the top electrodes are the same, and the numbers of the bottom compensation electrodes and the bottom electrodes are same; and

wherein the sizes and layouts of the top compensation electrodes and the top electrodes are substantially same, and the sizes and layouts of the bottom compensation electrodes and the bottom electrodes are substantially same.

8. The MEMS compensation structure of claim 7, wherein the compensation mass structure is fixed and does not move relatively with respect to the top compensation electrodes and the bottom compensation electrodes.

9. A MEMS device, comprising:

a mass structure, including at least one anchor;

at least one flexible structure connected with the mass structure at the at least one anchor;

a plurality of top electrodes, located above the mass structure to form a top capacitor circuit with the mass structure;

a plurality of bottom electrodes, located under the mass structure to form a bottom capacitor circuit with the mass structure;

a compensation mass structure, wherein the compensation mass structure and the mass structure are connected to a same voltage level;

a plurality of top compensation electrodes, wherein the top compensation electrodes and the bottom electrodes are connected to another voltage level, whereby the top capacitor and the bottom compensation capacitor form a parallel capacitor circuit; and

a plurality of bottom compensation electrodes, wherein the bottom compensation electrodes and the top electrodes are connected to yet another same voltage level, whereby the bottom capacitor and the top compensation capacitor form another parallel capacitor circuit;

wherein projections of the top electrodes on the mass structure along a normal direction of the mass structure are located at opposite sides of the anchor, and projections of the plural bottom electrodes on the mass structure along a normal direction of the mass structure are located at opposite sides of the anchor.