Inductive inertial sensor architecture and fabrication in packaging build-up layers

• US 9,429,427 B2
• Filed: 12/19/2012
• Issued: 08/30/2016
• Est. Priority Date: 12/19/2012
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Ma, Qing, Eid, Feras, Lin, Kevin, Swan, Johanna M., Teh, Weng Hong, Rao, Valluri R.
• Primary Examiner(s): Williams, Hezron E
• Assistant Examiner(s): Sinha, Tarun
• Application Number:
  US13/720,876
• Publication Number:
  US 20140165723A1
• Time in Patent Office: 1,350 Days
• Field of Search: 735/040.3, 735/041.2, 735/143.2
• US Class Current: 1/1
• CPC Class Codes: G01C 19/56 Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces
• CPC Class Codes: G01C 19/5776 Signal processing not specific to any of the devices covered by groups G01C19/5607 - G01C19/5719

Abstract

This invention relates to inductive inertial sensors employing a magnetic drive and/or sense architecture. In embodiments, translational gyroscopes utilize a conductive coil made to vibrate in a first dimension as a function of a time varying current driven through the coil in the presence of a magnetic field. Sense coils register an inductance that varies as a function of an angular velocity in a second dimension. In embodiments, the vibrating coil causes first and second mutual inductances in the sense coils to deviate from each other as a function of the angular velocity. In embodiments, self-inductances associated with a pair of meandering coils vary as a function of an angular velocity in a second dimension. In embodiments, package build-up layers are utilized to fabricate the inductive inertial sensors, enabling package-level integrated inertial sensing advantageous in small form factor computing platforms, such as mobile devices.

Claims

1. A gyroscope, comprising:

a substrate including a magnet;

a drive coil disposed over the substrate and within a magnetic field of the magnet to vibrate in a first dimension relative to the substrate as a function of a time varying current passing through the drive coil,

at least one sense coil disposed over the substrate and positioned with respect to the drive coil to register an inductance that varies as a function of an angular velocity in a second dimension, orthogonal to the first dimension,

wherein the first dimension is perpendicular to a plane of the substrate, wherein the magnetic field and the angular velocity are parallel to the plane of the substrate.

2. The gyroscope of claim 1, wherein the at least one sense coil comprises a pair of sense coils is to register a first and second mutual inductance that deviate from each other as a function of the angular velocity.

3. The gyroscope of claim 2, wherein the sense coils are disposed relative to the drive coil to register a differential in their mutual inductance in response to a displacement of the drive coil in a dimension other than the first dimension that is greater than a mutual inductance differential registered in response to displacement of the drive coil in the first dimension.

4. The gyroscope of claim 3, wherein the drive coil is planar in a plane parallel to the substrate and comprises four substantially orthogonal segments with a plurality of conductive anchors, and at least one pair of the conductive anchors providing terminals through which the time varying current is applied to the drive coil.

5. The gyroscope of claim 4, wherein the sense coils further comprise a first pair of sense coils having coil lengths parallel to segments on opposite sides of the drive coil extending along a first in-plane dimension to register a differential in mutual inductance in response to a displacement of the drive coil in a second in-plane dimension, orthogonal to the first in-plane dimension.

6. The gyroscope of claim 5, wherein the sense coils further comprise a second pair of sense coils having coil lengths parallel to segments on opposite sides of the drive coil extending along the second in-plane dimension, the second pair to register a differential in mutual inductance in response to a displacement of the drive coil in the first in-plane dimension.

7. The gyroscope of claim 2, wherein each of the pair of sense coils comprises at least one of:

a spiral with a plurality of turns made within a same plane parallel to the substrate;

or

a plurality of coils disposed along a length of the drive coil and connected in series;

or

one or more turns in a plane parallel to the substrate but not in the same plane as the drive coil, the one or more turns disposed symmetrically over a segment of the drive coil.

8. An integrated inertial sensor, comprising:

the gyroscope of claim 2; and

at least one of an amplifier or rotation calculator downstream of the sense coils, the amplifier to amplify a voltage differential registered by the pair of sense coils and the rotation calculator to determine a rotation based on the voltage differential registered by the pair of sense coils.

9. The integrated inertial sensor of claim 8, wherein the amplifier or rotation calculator comprise circuitry on an integrated circuit (IC) chip disposed within a same package as the gyroscope.

10. The integrated inertial sensor of claim 8, wherein the drive and sense coils comprise at least one metallization layer disposed within organic dielectric build-up layers of the package.

11. A method of determining an angular rate of rotation of a mobile device including a packaged integrated circuit (IC), the method comprising:

driving a time varying current through a first coil disposed within a first magnetic field of a first magnet embedded, along with the first coil, within the IC package dielectric to vibrate the first coil in a first dimension relative to the IC package;

generating first and second time varying voltage signals with a pair of sense coils through mutual induction responsive to displacement of the first coil, the first and second time varying voltage signals deviating from each other as a function of an angular velocity in a second dimension, orthogonal to the first dimension; and

determining a first of a yaw, pitch, or roll of the mobile device based on the first and second time varying voltage signals,

wherein the first coil is planar in a plane parallel to a plane of the substrate and the first coil comprises four substantially orthogonal segments with a plurality of conductive anchors, and wherein the time varying current is driven through at least one pair of the conductive anchors.

12. The method of claim 11, further comprising:

driving a time varying current through a second coil disposed within a second magnetic field, orthogonal to the first magnetic field to vibrate the second coil in the first dimension;

generating third and fourth time varying voltage signals with a pair of sense coils through mutual induction responsive to displacement of the second coil, the third and fourth time varying voltage signals deviating from each other as a function of an angular velocity in a dimension orthogonal to the second dimension; and

determining a second of a yaw, pitch, or roll of the mobile device based on the third and fourth time varying voltage signals.

13. A gyroscope, comprising:

a substrate including a magnet;

a drive coil disposed over the substrate and within a magnetic field of the magnet to vibrate in a first dimension relative to the substrate as a function of a time varying current passing through the drive coil,

at least one sense coil disposed over the substrate and positioned with respect to the drive coil to register an inductance that varies as a function of an angular velocity in a second dimension, orthogonal to the first dimension,

wherein the time varying current is driven through a first pair of conductive coil anchors, and wherein the sense coils include a second pair of conductive coil anchors and a portion of the coil disposed there between, the second pair of coil anchors registering self inductances that vary as a function of an angular velocity in a second dimension, orthogonal to the first dimension, and wherein a resonant frequency varies as a function of the self inductance and capacitance of a capacitor coupled across the second pair of coil anchors,

wherein the first dimension is parallel to the plane of the substrate, wherein the magnetic field and the angular velocity are perpendicular to the plane of the substrate, and wherein the second pair of anchors comprise springs to compress and extend along the second dimension in a manner that changes their self inductance.

14. The gyroscope of claim 13, wherein the springs are rectangle springs having at least a pair of conductor segments extending in the first dimension and joined at one end by a short segment extending in the second dimension.

15. An integrated inertial sensor, comprising:

the gyroscope of claim 13; and

a rotation calculator downstream of the sense coils, the rotation calculator to determine a rotation based on the resonant frequency.

16. The integrated inertial sensor of claim 15, wherein the rotation calculator comprises circuitry on an integrated circuit (IC) chip disposed along with the gyroscope within a same package.

17. The integrated inertial sensor of claim 15, wherein the coil comprises at least one metallization layer disposed within organic dielectric build-up layers of the package.