GYROMETER IN SURFACE TECHNOLOGY, WITH OUT-OF-PLANE DETECTION BY STRAIN GAUGE

• US 20100186506A1
• Filed: 01/22/2010
• Published: 07/29/2010
• Est. Priority Date: 01/23/2009
• Status: Active Grant

• Current Assignee: Commissariat a L'Energie Atomique (AES Corporation)
• Original Assignee: Commissariat a L'Energie Atomique (AES Corporation)
• Inventors: ROBERT, Philippe
• Granted Patent: US 8,375,788 B2
• Time in Patent Office: Days
• US Class Current: 73/504.120
• CPC Class Codes: G01C 19/574 the devices having two sensing masses in anti-phase motion

Abstract

The invention concerns a gyrometer-type device, comprised in a substrate (2, 50), and characterized in that it includes:

• • at least one mass (3, 3′, 31, 32, 33) defining, idle, a plane, arranged at a distance from an axis (Z, H, H′) of rotation contained in this plane, this mass being able to be caused to vibrate in this plane, perpendicular to the axis of rotation (Z),
  • at least two connecting arms to connect said mass to said axis of rotation;
  • means forming, for at least one of the arms, at least one connection with the substrate for a rotation around said axis of rotation,
  • at least one strain gauge, for detecting the rotational movement.

Claims

1. A device of the gyrometer type, for detecting a rotation around a first axis (Z), this device being realized from a substrate, and including:

a) A first zone, called thick zone, having a first thickness and including;

at least one mass, defining, idle, a plane, arranged at a distance from a second axis (Z, H, H′

) of rotation contained in this plane, this mass being able to be caused to vibrate in this plane, perpendicular to the first axis of rotation (Z),

at least two connecting arms to connect said mass to said second axis of rotation (Z, H, H′

),

b) means for causing said mass to vibrate in its plane,

c) a second zone, of second thickness forming, for at least one of the arms, at least one connection with the substrate for a rotation around said second axis of rotation (Z, H, H′

), this second zone having a thickness smaller than or equal to that of the first zone,

d) a third zone, called thin zone, with a thickness smaller than that of the second zone, forming at least one strain gauge of the suspended type, for detecting the rotational movement around said second axis of rotation, this third zone;

extending in a plane parallel to the plane of the substrate and not containing the axis of rotation,

extending in a plane perpendicular to the second axis of rotation,

being connected, on one hand, to one of the first and second zones and, on the other hand, to the substrate.

2. The device according to claim 1, in which the first zone includes two masses, each mass being arranged, idle, at a distance from a second axis (Z, H, H′

) of rotation of this mass, the two distances between each of these two masses and its second axis (Z, H, H′

) of rotation being equal.

3. The device according to claim 2, the two masses having a second common axis of rotation (Z), common with the first axis of rotation, each of the two arms connecting each of the two masses to said second common axis of rotation.

4. The device according to claim 3, comprising at least two gauges for detecting the rotational movement, these two gauges being differential mounted.

5. The device according to claim 2, the two masses having second axes of rotation (H, H′

) different from each other, parallel to each other and to the first axis of rotation, the first zone including at least four arms, including two arms to connect each mass to its second axis of rotation.

6. The device according to claim 5, also including a coupling device coupling the two masses in anti-phase.

7. The device according to claim 5, including at least one gauge for detecting the rotational movement of each mass.

8. The device according to claim 1, said at least one strain gauge being made in a piezoresistive material such as monocrystalline or polycrystalline silicon, or of silicon nanowires, or of monocrystalline or polycrystalline SiGe, or of carbon nanotubes.

9. The device according to claim 1, said at least one strain gauge comprising a detection resonator, including at least one vibrating strip, an excitation means and a detector for vibrations.

10. The device according to claim 9, the excitation of the vibrating strip and/or the detection of the resonance being done electrostatically via at least one electrode arranged, in relation to the vibrating strip, in the direction of vibration.

11. The device according to claim 9, including a piezoresistive device for detecting the resonance, arranged on the vibrating strip.

12. The device according to claim 1, said at least one strain gauge and the first zone both being situated on the same side in relation to a common plane, lower plane (N2) of the first zone in relation to the substrate.

13. The device according to claim 1, the first zone being situated between an upper plane (N1) and a lower plane (N2), the axis (Z, H, H′

) of rotation being in a plane parallel to these two planes.

14. The device according to claim 13, the point(s) of application (P) of the strains produced on each of the gauges being in a plane which is parallel to the plane containing the axis (Z, H, H′

) of rotation and perpendicular to each of the upper (N1) and lower (N2) planes or in planes which are parallel to the plane containing the axis (Z, H, H′

) of rotation and perpendicular to each of the upper (N1) and lower (N2) planes.

15. The device according to claim 14, including a single gauge per connecting arm, the point of application of strains on this gauge being in a plane, parallel to the plane containing the axis (Z, H, H′

) of rotation and perpendicular to each of the upper (N1) and lower (N2) planes, combined with the plane passing through the axis of rotation, or different from that plane.

16. The device according to claim 15, including several gauges per connecting arm, the points of application of the strains on these gauges being in planes parallel to the plane containing the axis (Z, H, H′

) of rotation and perpendicular to each of the upper (N1) and lower (N2) planes, different from that containing the axis of rotation.

17. The device according to claim 1, the thickness of the third zone being smaller than or equal to half of the thickness of the second zone.

18. A device of the gyrometer type, for detecting a rotation around a first axis (Z), this device being realized from a substrate, and including:

a) A first zone, called thick zone, having a first thickness and comprising two masses, defining, idle, a plane, each of said two masses being arranged, idle, at a distance from a second axis (Z, H, H′

) of rotation of this mass and contained in said plane, the two distances between each of these two masses and its second axis (Z, H, H′

) of rotation being equal, each of said two masses being able to be caused to vibrate in this plane, perpendicular to the first axis of rotation (Z), said two masses having a second common axis of rotation (Z), common with the first axis of rotation, each of the two arms connecting each of the two masses to said second common axis of rotation,

at least two connecting arms to connect said two masses to said second axis of rotation (Z, H, H′

),

e) electrostatic combs for causing said masses to vibrate in their plane,

f) a second zone, of second thickness forming, for at least one of the arms, at least one connection with the substrate for a rotation around said second axis of rotation (Z, H, H′

), this second zone having a thickness smaller than or equal to that of the first zone,

g) a third zone, called thin zone, with a thickness smaller than that of the second zone, forming at least one strain gauge of the suspended type, for detecting the rotational movement around said second axis of rotation, this third zone;

extending in a plane parallel to the plane of the substrate and not containing the axis of rotation,

extending in a plane perpendicular to the second axis of rotation,

being connected, on one hand, to one of the first and second zones and, on the other hand, to the substrate.

19. A device of the gyrometer type, for detecting a rotation around a first axis (Z), this device being realized from a substrate, and including:

a) A first zone, called thick zone, having a first thickness and comprising two masses, defining, idle, a plane, each of said two masses being arranged, idle, at a distance from a second axis (Z, H, H′

) of rotation of this mass and contained in said plane, the two distances between each of these two masses and its second axis (Z, H, H′

) of rotation being equal, each of said two masses being able to be caused to vibrate in this plane, perpendicular to the first axis of rotation (Z), said two masses having second axes of rotation (H, H′

) different from each other, parallel to each other and to the first axis of rotation, the first zone including at least four arms, including two arms to connect each mass to its second axis of rotation.

at least two connecting arms to connect said two masses to said second axis of rotation (Z, H, H′

),

h) electrostatic combs for causing said masses to vibrate in their plane,

i) a second zone, of second thickness forming, for at least one of the arms, at least one connection with the substrate for a rotation around said second axis of rotation (Z, H, H′

), this second zone having a thickness smaller than or equal to that of the first zone,

j) a third zone, called thin zone, with a thickness smaller than that of the second zone, forming at least one strain gauge of the suspended type, for detecting the rotational movement around said second axis of rotation, this third zone;

extending in a plane parallel to the plane of the substrate and not containing the axis of rotation,

extending in a plane perpendicular to the second axis of rotation,

being connected, on one hand, to one of the first and second zones and, on the other hand, to the substrate.