Suspended micromachined structure

• US 6,426,538 B1
• Filed: 01/16/2001
• Issued: 07/30/2002
• Est. Priority Date: 01/16/2001
• Status: Expired due to Fees

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Knowles, Gary R.
• Primary Examiner(s): Lee, Eddie
• Assistant Examiner(s): Ortiz, Edgardo
• Application Number:
  US09/761,291
• Publication Number:
  US 20020093067A1
• Time in Patent Office: 560 Days
• Field of Search: 257/419, 257/420, 257/415, 257/417, 257/418, 257/252, 257/254, 735/041.2, 736/51, 735/04, 735/05, 735/14, 438/53, 438/50, 438/52
• US Class Current: 257/417
• CPC Class Codes: B81B 2201/0242 Gyroscopes
• CPC Class Codes: B81B 2203/0109 Bridges
• CPC Class Codes: B81B 2203/051 Translation according to an axis parallel to the substrate
• CPC Class Codes: B81B 2203/053 Translation according to an axis perpendicular 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: G01C 19/5719 using planar vibrating masses driven in a translation vibration along an axis

Abstract

A suspended micromachined structure including a proof mass and multiple support arms configured to suspend the mass above a substrate. At least one support arm may include two spring elements, each attached to the substrate as well as to a rigid lateral element. Thus, there may be three points of attachment along each lateral element. These points of attachment create three effective flexure points along each rigid lateral element that allow the proof mass to move with a great deal of freedom axially, parallel to the substrate. The linearity of the spring constant that acts on the proof mass may be improved.

Claims

1. A micromachined device comprising:

a movable mass;

a plurality of support arms attached to the movable mass;

each of the support arms flexibly coupling the movable mass to a substrate;

at least on e of the support arms including a first end coupled to the substrate and a second end coupled to the substrate;

wherein the movable mass is connected to the at least one support arm at a point between the first end and the second end of the support arm.

2. The micromachined device of claim 1, wherein the at least one support arm comprises:

a first spring element attached to the substrate;

a second spring element attached to the substrate;

a rigid lateral element having a first end and a second end, the first end of the rigid lateral element connected to the first spring element and the second end o f the rigid lateral element connected to the second spring element;

wherein the movable mass is connected to the rigid lateral element of the at least one support arm between the first and second ends of the rigid lateral element.

3. The micromachined device of claim 2, wherein the movable mass is connected to the middle of the rigid lateral element.

4. The micromachined device of claim 2 wherein the connection of the first spring element to the rigid lateral element creates a first end flexure point, the connection of the second spring element to the rigid lateral element creates a second end flexure point, and the connection of the movable mass to the rigid lateral element creates a middle flexure point.

5. The micromachined device of claim 4, wherein the first end flexure point, the second end flexure point, and the middle flexure point form a substantially straight line.

6. The micromachined device of claim 5, wherein the substantially straight line comprises an axis of alignment.

7. The micromachined device of claim 6, wherein the axis of alignment is parallel to an axis of oscillation of the movable mass.

8. The micromachined device of claim 7, wherein when the movable mass moves along the axis of oscillation, the middle flexure point moves along the axis of alignment.

9. The micromachined device of claim 1, further including a second support arm having a first end coupled to the substrate and a second end coupled to the substrate;

wherein the movable mass is connected to the second support arm at a point between the first end and the second end of the support arm.

10. The micromachined device of claim 9, wherein the at least one support arm and the second support arm are positioned on the same side of the movable mass.

11. The micromachined device of claim 9, wherein the at least on support arm and the second support arm are positioned on opposite sides of the movable mass.

12. The micromachined device of claim 6, wherein the first and second spring elements are symmetrical about the axis of alignment.

13. A micromachined device comprising:

a movable mass having first and second sides;

a first support arm extending from the first side of the movable mass;

a second support arm extending from the second side of the movable mass;

each of the support arms flexibly coupling the movable mass to a substrate;

each of the support arms includes a first end coupled to the substrate and a second end coupled to the substrate;

wherein the movable mass is connected to each of the support arms at a point between the first end and the second end of the support arm.

14. The micromachined device of claim 13, wherein each of the support arms comprise:

a first spring element attached to the substrate;

a second spring element attached to the substrate;

a rigid lateral element having a first end and a second end, the first end of the rigid lateral element connected to the first spring element and the second end of the rigid lateral element connected to a second spring element;

wherein the movable mass is connected to the rigid lateral element of each support arm between the first and second ends of the rigid lateral elements.

15. The micromachined device of claim 14, wherein the movable mass is connected to the middle of each of the rigid lateral elements.

16. The micromachined device of claim 14, wherein for each support arm the connection of the first spring element to the rigid lateral element creates a first end flexure point, the connection of the second spring element to the rigid lateral element creates a second end flexure point, and the connection of the movable mass to the rigid lateral element creates a third flexure point.

17. The micromachined device of claim 16, wherein the first end flexure point, the second end flexure point, and the middle flexure point for each support arm forms a substantially straight line.

18. The micromachined device of claim 17, wherein the substantially straight line for each support arm comprises an axis of alignment.

19. The micromachined device of claim 18, wherein the axis of alignment for each support arm is parallel to every other support arm'"'"'s axis of alignment.

20. The micromachined device of claim 19, wherein when the movable mass moves along the axis of oscillation, the middle flexure point of each support arm moves along its respective axis of alignment.

21. A micromachined device comprising:

a movable mass having four connecting arms; and

four support arms, each of the support arms extending from a respective connecting arm, the support arms flexibly coupling the movable mass to a substrate;

each of the four support arms including a first end connected to the substrate, a second end connected to the substrate, and a rigid lateral element;

each rigid lateral element including a first end and a second end, the first end of the rigid lateral element connected to a first spring element and the second end of the rigid lateral element connected to a second spring element;

each connecting arm of the movable mass being connected to each rigid lateral element between the first and second ends of each rigid lateral element;

wherein the connection of the first spring element to each rigid lateral element creates a first end flexure point, the connection of the second spring element to each rigid lateral element creates a second end flexure point, and the connection of each connecting arm to each rigid lateral element creates a middle flexure point.

22. The device of claim 21, wherein the three flexure points of each support arm are aligned in a substantially straight line that comprises an axis of alignment.

23. The device of claim 22, wherein each axis of alignment of the four support arms are parallel to each other and to an axis of oscillation of the movable mass.

24. The device of claim 22, wherein the middle flexure point of each support arm moves along its respective axis of alignment when the movable mass moves along the axis of oscillation.