Bending actuators and sensors constructed from shaped active materials and methods for making the same

• US 6,965,189 B2
• Filed: 09/20/2002
• Issued: 11/15/2005
• Est. Priority Date: 09/20/2002
• Status: Expired due to Fees

• Current Assignee: Monodrive Inc.
• Original Assignee: Monodrive Inc.
• Inventors: Menzel, Christoph P.
• Primary Examiner(s): Schuberg, Darren
• Assistant Examiner(s): ADDISON, KAREN B
• Application Number:
  US10/251,217
• Publication Number:
  US 20040056567A1
• Time in Patent Office: 1,152 Days
• Field of Search: H01/L04.1/07, H01/L04.1/09, H01/L04.1/08, 310/328, 310330-332, 310/359, 310/367, 310/365
• US Class Current: 310/330
• CPC Class Codes: H10N 30/078 by sol-gel deposition
• CPC Class Codes: H10N 30/081 by coating or depositing using masks, e.g. lift-off
• CPC Class Codes: H10N 30/204 using bending displacement, e.g. unimorph, bimorph or multimorph cantilever or membrane benders
• CPC Class Codes: H10N 30/2042 Cantilevers, i.e. having one fixed end
• CPC Class Codes: H10N 30/2048 having non-planar shape
• CPC Class Codes: H10N 30/302 Sensors
• CPC Class Codes: H10N 30/40 with electrical input and electrical output, e.g. functioning as transformers
• CPC Class Codes: H10N 35/00 Magnetostrictive devices integrated devices or assemblies of multiple devices H10N39/00
• CPC Class Codes: H10N 35/01 Manufacture or treatment

Abstract

Bender devices are demonstrated by developing non-uniform fields within a homogeneous, non-planar single slab active member material of non-uniform thickness through geometrical constraints and electrode placement. Single slab actuators are demonstrated for semiconductor designs including MEMS applications. Single slab bender periodic designs are demonstrated to be well suited for MEMS fabrication. Shaped actuators having a topological pattern formed across at least one portion are demonstrated to induced strain at the patterned portion of the actuator, causing the patterned portion to flare into open and close positions upon application of an external field. Voltage transformers, spark generators, power sources, and sensors are developed using the non-planar, homogeneous, single slab active member material of non-uniform thickness. Last, semiconductor process design techniques are demonstrated for periodic and other non-planar single slab actuators.

Claims

1. An apparatus for actuation comprising a non-planar shaped, single active member slab of continuous homogeneous material and non-uniform thickness for bending, said apparatus having non-uniform fields induced therein when subjected to an external field, said non-uniform fields defined by said non-planar shape and generating moments to bend said apparatus.

2. The apparatus of claim 1 wherein said homogeneous material further comprises having measurable physical parameters responsive to a distribution of said non-uniform fields.

3. The apparatus of claim 1 further comprising having said non-planar shape designed to adjust non-uniformity of said non-uniform fields to reduce internal stress within said single active member slab.

4. The apparatus of claim 3 wherein said non-uniformity of said non-uniform fields reduces internal stress through a linear distribution of said non-uniform fields.

5. The apparatus of claim 1 further comprising having said non-uniform fields defined by said non-planar shape and electrode placement on said single active member slab.

6. The apparatus of claim 1 wherein said non-planar shaped, single active member slab of continuous homogeneous material bends in response to induced strain developed from said non-uniform fields.

7. The apparatus of claim 1 comprising a single layer of continuous homogeneous piezoelectric, electrostrictive or magnetostrictive material.

8. The apparatus of claim 1 wherein said external field comprises electric, magnetic, or electromagnetic fields.

9. The apparatus of claim 1 wherein said non-planar shaped, single active member slab further comprises a non-rectilinear shape adapted to alter internal fields induced by said external field and enhance field non-uniformity therein.

10. The apparatus of claim 1 wherein said non-planar shaped, single active member slab further comprises straight-edged surfaces adapted to alter internal fields induced by said external field and enhance field non-uniformity therein.

11. The apparatus of claim 10 further comprising said active member slab as a piecewise planar slab.

12. The apparatus of claim 6 wherein said non-planar shaped, single active member slab of continuous homogeneous material comprises a first internal region of lesser strain and a second internal region of greater strain when said active member is subjected to said external field.

13. The apparatus of claim 12 wherein said induced strain varies as a linear function, a square-root function, or as a square function with respect to said non-uniform thickness of said apparatus.

14. The apparatus of claim 1 wherein said single layer active member comprises a diaphragm or membrane shape having non-uniform thickness.

15. The apparatus of claim 1 further comprising a plurality of said non-planar shaped, single active member slabs of continuous, homogeneous material bonded together, wherein each of said single active member slabs has non-uniform fields induced therein when subjected to an external field, said non-uniform fields defined by said non-planar shape and generating moments to bend each of said single active member slabs independently.

16. The apparatus of claim 15 further comprising having said plurality of said non-planar shaped, single active member slabs in a vertically stacked configuration.

17. The apparatus of claim 15 further comprising having said plurality of said non-planar shaped, single active member slabs in a side-by-side configuration.

18. The apparatus of claim 2 wherein said measurable physical parameters include force related properties.

19. The apparatus of claim 18 wherein said force related properties comprise stress and strain.

20. An apparatus comprising a non-planar shaped, single active member slab of continuous homogeneous material and non-uniform thickness for sensing, said apparatus having fields induced therein when subjected to an external energy, said fields defined by said non-planar shape and generating non-zero average electrical reactions to said external fields, causing said apparatus to sense.

21. The apparatus of claim 20 further comprising having said non-planar shaped, single layer active member of homogeneous material induce a potential difference across portions or all of said single layer active member when said active member is subjected to said external energy.

22. Apparatus of claim 21 where the said external energy comprises infrared radiation, electric fields, magnetic fields, pressure, acceleration, or mechanical loading.

23. The apparatus of claim 22 wherein said active member slab comprises at least one thicker portion and at least one thinner portion, and generating said potential difference between said at least one thicker portion and said at least one thinner portion when said slab is exposed to said external energy.

24. The apparatus of claim 20 further comprising a single layer of homogeneous piezoelectric, electrostrictive, magnetostrictive, or pyroelectric material.

25. The apparatus of claim 20 further comprising a topological pattern repeated across at least one surface of said active member.

26. An apparatus for bending comprising a continuous homogeneous, single active member slab of non-planar geometry having a first portion and a second portion, said apparatus having non-uniform fields induced therein when subjected to an external field, said non-uniform fields producing approximately no strain in said first portion and strain responsive to said non-uniform fields in said second portion, and generating moments to bend said apparatus.

27. The apparatus of claim 26 comprising a single layer of continuous homogeneous piezoelectric, electrostrictive, or magnetostrictive material.

28. An apparatus for bending comprising a continuous homogeneous, single active member slab of non-planar geometry having a first active portion and a second active portion, said apparatus having non-uniform fields induced therein when subjected to an external field, said non-uniform fields producing strain fields responsive to said external fields, said strain fields induced in said first active portion different from said strain fields induced in said second active portion, and generating moments to bend said apparatus.

29. The apparatus of claim 28 comprising having said strain fields in said first active portion of a different strength or polarity of said strain field in said second active portion.

30. A voltage transformer comprising a non-planar shaped, single active member slab of continuous homogeneous material and non-uniform thickness, a first electrode pair, and a second electrode pair, said transformer having non-uniform fields induced therein when a first potential difference is applied across said first electrode pair, said non-uniform fields defined by said non-planar shape and causing said transformer to generate a second potential difference across said second electrode pair.

31. The voltage transformer of claim 30 comprising said first electrode pair having a first top electrode and a bottom electrode, and said second electrode pair having a second top electrode and said bottom electrode, one of said electrode pairs used as an input and the other of said electrode pair used as an output for said voltage transformer.

32. The voltage transformer of claim 30 comprising a first stress developed between said first electrode pair and a second stress developed between said second electrode pair, said first stress different from said second stress, said first and second stress not expressed as strain.

33. The voltage transformer of claim 30 comprising a step-up or step-down voltage transformation based on a difference in active member material non-uniform thickness at the first and second electrodes.

34. The voltage transformer of claim 31 comprising said first top electrode attached to a peak on said top surface, said second top electrode attached to a trough on said top surface.

35. The voltage transformer of claim 30 comprising a mechanically clamped portion of said single active member slab.

36. The voltage transformer of claim 30 comprising a topological pattern repeated across at least one surface of said active member.

37. A bending actuator comprising a non-planar shaped, single active member slab of continuous homogeneous material, said slab including a top, a bottom, a non-uniform thickness, a bending portion, a predetermined direction of bending, said top and bottom aligned in said predetermined direction of bending;

said bending portion mechanically unrestrained in said predetermined direction of bending.

38. The bending actuator of claim 37 further comprising having said bending portion adapted to displace through said predetermined direction of bending when said bending actuator is subjected to an external field.

39. An apparatus comprising a non-planar shaped, single active member slab of continuous homogeneous material and non-uniform thickness for generating electrical power, said apparatus having fields induced therein when subjected to an external energy, said fields defined by said non-planar shape and generating non-zero average electrical reactions to said external fields, causing said apparatus to transform said external energy to electrical energy.

40. The apparatus or claim 39 wherein said external energy comprises mechanical energy.