Richard R Waters

US Patent:

6546798, Apr 15, 2003

Filed:

Jun 26, 2001

Appl. No.:

09/892301

Inventors:

Richard L. Waters - San Diego CA
Monti E. Aklufi - San Diego CA

Assignee:

The United States of America as represented by the Secretary of the Navy - Washington DC

International Classification:

G01P 300

US Classification:

7350401, 356460

Abstract:

A gyroscope is based upon the integration of an optical resonant cavity and a photodiode to detect minute perturbations due to angular forces. A Fabry-Perot cavity is created from two parallel semitransparent mirrors used in conjunction with a monochromatic light source. One mirror is fixed while the other is allowed to rotate with respect to the first mirror. A resonant cavity is thereby formed on either side of the axis. The gap between the mirrors is set so that light transmission through the mirrors is optimized. Rotation of the mirror from this position causes the distance between the mirrors to be altered and the light transmission on either side of the rotational axis to be change. Photodiodes on these sides sense this change as a change in photo-generated current, enabling the amount of change in rotation to be calculated. The photo-currents can be differentially amplified for sensitivity.

US Patent:

6550330, Apr 22, 2003

Filed:

Jun 21, 2001

Appl. No.:

09/886293

Inventors:

Richard L. Waters - San Diego CA
Chris Hutchens - Stillwater OK
Monti E. Aklufi - San Diego CA

Assignee:

The United States of America as represented by the Secretary of the Navy - Washington DC

International Classification:

G01P 1500

US Classification:

7351426, 356454

Abstract:

An improvement to an optical accelerometer based upon the monolithic integration of a Fabry-Perot interferometer and a p n silicon photosensor includes using one or more pairs of optical accelerometers wherein each pair provides for greater accelerometer sensitivity than a single independent accelerometer, and allows for a reduction in common mode noise due to amplitude and phase difference variations of the utilized light source as well as supply voltage. The differential approach of the invention provides for the biasing of the optical accelerometers such that their output signals are 180 degrees out of phase with each other.

US Patent:

6581465, Jun 24, 2003

Filed:

Mar 14, 2001

Appl. No.:

09/808570

Inventors:

Richard L. Waters - San Diego CA
Monti E. Aklufi - San Diego CA

Assignee:

The United States of America as represented by the Secretary of the Navy - Washington DC

International Classification:

G01P 1508

US Classification:

7351426, 356506

Abstract:

An accelerometer is based upon the monolithic integration of a Fabry-Perot interferometer and a p n silicon photosensor. Transmission of light through a Fabry-Perot etalon is exponentially sensitive to small displacements in a movable mirror due to an applied accelerating force. The photosensor converts this displacement into an electrical signal as well as provides for additional amplification. Because the interferometer and photosensor are monolithically integrated on a silicon substrate, the combination is compact and has minimal parasitic elements, thereby reducing the accelerometers noise level and increasing its signal-to-noise ratio (SNR). The accelerometers sensitivity can be user-controlled by any one or a combination of factors: providing an electrostatic potential across the mirrors of the Fabry-Perot etalon hence selecting a desired gap therebetween; adjusting the power of the light projected to the photosensor; and pulsing the light at a selected frequency to minimize 1/f inherent system noise in the response of the accelerometer.

US Patent:

6763718, Jul 20, 2004

Filed:

Sep 17, 2002

Appl. No.:

10/245617

Inventors:

Richard L. Waters - San Diego CA
Monti E. Aklufi - San Diego CA

Assignee:

The United States of America as represented by the Secretary of the Navy - Washington DC

International Classification:

G01P 1508

US Classification:

7351426, 356506

Abstract:

An accelerometer is based upon the monolithic integration of a Fabry-Perot interferometer and a p n silicon photosensor. Transmission of light through a Fabry-Perot interferometer cavity is exponentially sensitive to small displacements in a movable mirror due to an applied accelerating force. The photosensor converts this displacement into an electrical signal as well as provides for additional amplification. Because the interferometer and photosensor are monolithically integrated on a silicon substrate, the combination is compact and has minimal parasitic elements, thereby reducing the accelerometers noise level and increasing its signal-to-noise ratio (SNR). The accelerometers sensitivity can be user-controlled by any one or a combination of factors: adjusting the length between the mirrors of the Fabry-Perot cavity; adjusting the power of the light projected to the photosensor; and pulsing the light at a selected frequency to minimize 1/f inherent system noise in the response of the accelerometer.

US Patent:

6948388, Sep 27, 2005

Filed:

Dec 18, 2003

Appl. No.:

10/739751

Inventors:

Stanley R. Clayton - Spring Valley CA, US
Stephen D. Russell - San Diego CA, US
Mark R. Roser - San Diego CA, US
Richard L. Waters - San Diego CA, US

Assignee:

The United States of America as represented by the Secretary of the Navy - Washington DC

International Classification:

G01K011/22
G01K007/00
G01N025/32

US Classification:

7386268, 734321, 73 2321, 73 3106, 331 57, 331 65, 257253, 422 90, 340634, 324451, 324236, 324 715

Abstract:

A sensing system includes a ring oscillator that emits electromagnetic radiation at a characteristic frequency. The ring oscillator comprises an odd number plurality of inverters that are electrically connected in series. The sensing system also comprises a temperature stabilized voltage source that is used to supply voltage to the inverters of the ring oscillator. A sensing load for sensing a change in a preselected environmental condition is operably connected to the ring oscillator. When the load senses the preselected environmental condition, the sensing load alters the characteristic frequency of the ring oscillator and hence the electromagnetic radiation as emitted by the ring oscillator. A pick-up antenna receives the electromagnetic radiation as emitted by the ring oscillator and detection electronics, operably coupled to the pick-up antenna, measure the frequency of the electromagnetic radiation as received by the pick-up antenna.

US Patent:

7425453, Sep 16, 2008

Filed:

Jan 22, 2004

Appl. No.:

10/763133

Inventors:

Chris Hutchens - Stillwater OK, US
Richard L. Waters - San Diego CA, US

Assignee:

The United States of America as represented by the Secretary of the Navy - Washington DC

International Classification:

G01N 21/01
G01N 21/27
G01N 33/00
G01J 3/26

US Classification:

436165, 356454, 422 8205, 422 8209, 422 86, 422 91, 436104, 436111, 436113, 436120, 436131, 436132, 436139, 436164, 436167, 436171

Abstract:

A Fabry-Perot cavity has a pair of partially transmissive, partially reflective, surfaces. A first of the surfaces is flexibly suspended adjacent and parallel to a second of the surfaces. A gap exists between the surfaces. A variable electrostatic potential permits this gap to be adjusted. A translucent chemical layer is disposed on the first surface. A photosensor is attached to the second surface. Light irradiates the photosensor through the chemical layer and the first and second surfaces wherein the light is also partially reflected between the surfaces. A sensing environment is provided wherein an agent undergoes a reaction with the chemical layer as well as an environment wherein the reaction does not occur. The output of the photosensor is measured to assess a change in spectrum and spectral intensity for each of the sensing environments. The gap between the surfaces as well as the light used are selected to provide an optimum photosensor output.

US Patent:

7501726, Mar 10, 2009

Filed:

Jul 28, 2004

Appl. No.:

10/911748

Inventors:

Richard L. Waters - San Diego CA, US
Patrick M. Sullivan - San Diego CA, US
Barry R. Hunt - San Diego CA, US

Assignee:

The United States of America as represented by the Secretary of the Navy - Washington DC

International Classification:

H02K 33/00

US Classification:

310 36

Abstract:

A micro-electro-mechanical system (MEMS) power generator employing a plurality of magnetic masses disposed to oscillate on spring elements in a manner that produces an unusually steep flux gradient at one or more conductive coils, thereby harvesting a substantial portion of the available mechanical energy. The energy from ambient mechanical vibration is harvested to produce electrical power sufficient to power individual electronic elements for a variety of low-cost and high-performance distributed sensor systems for medical, automotive, manufacturing, robotics, and household applications.

US Patent:

7692340, Apr 6, 2010

Filed:

Jan 28, 2009

Appl. No.:

12/360892

Inventors:

Richard L. Waters - San Diego CA, US
Patrick M. Sullivan - San Diego CA, US
Barry R. Hunt - San Diego CA, US

Assignee:

United States of America as represented by the Secretary of the Navy - Washington DC

International Classification:

H02K 33/00

US Classification:

310 36

Abstract:

A vibrational energy harvesting apparatus comprising: a substrate having a plurality of integral compliant regions; at least two ferromagnetic masses each coupled to a corresponding one or more of the integral compliant regions such that at least one of the ferromagnetic masses moves with respect to the substrate responsive to substrate acceleration, each ferromagnetic mass having an inner magnetic pole disposed such that the inner magnetic poles are separated by a gap, wherein the magnetic polarities of the inner magnetic poles on the opposing sides of the gap are similar; wherein the inner magnetic poles form a steep flux gradient region in and around the gap; and a coil coupled to the substrate and disposed within the steep flux gradient region where it is exposed to a changing magnetic flux arising from motion of at least one of the ferromagnetic masses with respect to the substrate.