United States Patent (19)
`Discenzo et al.
`
`54
`
`(75)
`
`MICRO-VISCOSITY SENSOR AND
`LUBRICATION ANALYSIS SYSTEM
`EMPLOYING THE SAME
`
`Inventors: Frederick M. Discenzo, Brecksville;
`Chung-Chiun Liu, Cleveland Heights;
`Donald L. Feke, Chesterland; Laurie
`Ann Dudik, South Euclid, all of Ohio
`Assignee: Reliance Electric Industrial
`Company, Cleveland, Ohio
`
`Appl. No.: 09/054,117
`Filed:
`Apr. 2, 1998
`Int. Cl." ............................ G01N 9/00; G01N 11/16
`U.S. Cl. ....................... 73/54.01; 73/54.24; 73/54.41;
`73/61.79; 422/68.1
`Field of Search .......................... 422/68.1; 73/54.01,
`73/54.24, 54.41, 64.53, 61.79
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`2,837,913 6/1958 Rich et al. .................................. 73/59
`3.256,741
`6/1966 Wise .............
`... 73/432
`3,393,553 7/1968 Kleinschmidt .............................. 73/54
`4,200,541 4/1980 Kinner et al. .....
`... 252/12.2
`4,675,662 6/1987 Kondo et al. .....
`... 340/631
`4,782,332 11/1988 Cipriset al. ......
`... 340/603
`4,783,987 11/1988 Hager et al. ......
`... 73/32 A
`4,792,791 12/1988 Cipriset al. ......
`... 340/603
`4,798,738
`1/1989 Yafuso et al. ............................... 427/2
`4,922,745 5/1990 Rudkin et al. ...........
`... 73/32 A
`4,926,682 5/1990 Holm-Kennedy et al. ................. 73/54
`4,935,040 6/1990 Goedert ....................
`... 55/197
`4.941,346
`7/1990 Suzuki et al. .....
`... 73/54
`5,004,583
`4/1991 Guruswamy et al. .................... 422/58
`5,038,893 8/1991 Willner et al. ........................... 184/7.4
`5,151,110 9/1992 Bein et al. .................................. 55/75
`5,199,298 4/1993 Ng et al. ...
`... 73/54.01
`5,200,027 4/1993 Lee et al. ......
`... 156/651
`5,359.881 11/1994 Kalotay et al. ........................ 73/54.06
`5,417,821
`5/1995 Pyke ..................................... 204/153.1
`5,418,058 5/1995 Li et al. .................................. 428/327
`
`US006023961A
`Patent Number:
`11
`(45) Date of Patent:
`
`6,023,961
`Feb. 15, 2000
`
`- - - - - 356/246
`
`1/1996 Salnick et al. .......................... 376/245
`5,485,491
`1/1996 Johnson ..............
`... 73/863.71
`5,487.313
`5,572,328 11/1996 Fouckhardt et al. .................... 356/440
`5,581,028 12/1996 Barth et al. .......................... 73/204.26
`5,614,830 3/1997 Dickert et al. .......................... 324/553
`5,633,809 5/1997 Wissenbach et al.
`. 364/510
`5,644,395 7/1997 Folta ...................
`5,646,039 7/1997 Northrup et al.
`... 435/287.2
`5,660,728 8/1997 Saaski et al. ........................... 210/251
`5,662,165 9/1997 Tubel et al...
`166/250.01
`5,852,229 12/1998 Josse et al. ............................ 73/24.06
`OTHER PUBLICATIONS
`Karagounis, et al. “A Pd-PdO Film Potentiometric pH
`Sensor', IEEE Transactions on Biomedical Engineering,
`vol. BME-33, No. 2, Feb. 1986.
`Berkeley MicroInstruments, MicroViscometer Model
`BMV100, Jan. 1998.
`Primary Examiner Hezron Williams
`Assistant Examiner J. David Wiggins
`Attorney, Agent, or Firm-Himanshu S. Amin; John M.
`Miller; John J. Horn
`ABSTRACT
`57
`A micro-Viscosity Sensor for measuring the Viscosity of a
`lubricant. The micro-Viscosity Sensor including at least one
`finger-like element or an array of finger-like elements ver
`tically extending from the Surface of a Semiconductor base,
`the at least one finger-like element being oscillated at a
`desired frequency. The power required to oscillate the at
`least one-finger-like element is monitored because the power
`required is a function of the viscosity of the lubricant. The
`Sensor also includes a temperature detector, wherein the
`thermal conductivity of the temperature detector varies in
`correspondence with the temperature of the lubricant. A first
`Set of electrical contacts provides for electrical connection to
`the at least one finger-like element; and a Second Set of
`electrical contacts provides for electrical connection to the
`temperature detector. The viscosity of the lubricant is deter
`mined based on the temperature of the lubricant correlated
`with the power required to oscillate the at least one-finger
`like element at a particular frequency.
`36 Claims, 15 Drawing Sheets
`
`
`
`- 40
`
`- 20
`
`Abbott
`Exhibit 1013
`Page 001
`
`

`

`U.S. Patent
`
`Feb. 15, 2000
`
`Sheet 1 of 15
`
`6,023,961
`
`
`
`| -61-I
`
`Abbott
`Exhibit 1013
`Page 002
`
`

`

`U.S. Patent
`
`Feb. 15, 2000
`
`Sheet 2 of 15
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`6,023,961
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`Abbott
`Exhibit 1013
`Page 003
`
`

`

`U.S. Patent
`US. Patent
`
`Feb. 15, 2000
`
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`6,023,961
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`Abbott
`Exhibit 1013
`Page 005
`
`

`

`U.S. Patent
`
`Feb. 15, 2000
`
`Sheet 5 of 15
`
`6,023,961
`
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`
`Abbott
`Exhibit 1013
`Page 006
`
`

`

`U.S. Patent
`
`Feb. 15, 2000
`
`Sheet 6 of 15
`
`6,023,961
`
`
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`Abbott
`Exhibit 1013
`Page 007
`
`

`

`U.S. Patent
`
`Feb. 15, 2000
`
`Sheet 7 of 15
`
`6,023,961
`
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`Abbott
`Exhibit 1013
`Page 008
`
`

`

`U.S. Patent
`
`6,023,961
`
`09 -61-I
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`Abbott
`Exhibit 1013
`Page 009
`
`

`

`U.S. Patent
`
`Feb. 15, 2000
`
`Sheet 9 of 15
`
`6,023,961
`
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`Abbott
`Exhibit 1013
`Page 010
`
`

`

`U.S. Patent
`
`Feb. 15, 2000
`
`Sheet 10 Of 15
`
`6,023,961
`
`
`
`Abbott
`Exhibit 1013
`Page 011
`
`

`

`U.S. Patent
`
`Feb. 15, 2000
`
`Sheet 11 Of 15
`
`6,023,961
`
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`
`Abbott
`Exhibit 1013
`Page 012
`
`

`

`U.S. Patent
`
`Feb. 15, 2000
`
`Sheet 12 of 15
`
`6,023,961
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`
`Abbott
`Exhibit 1013
`Page 013
`
`

`

`U.S. Patent
`
`Feb. 15, 2000
`
`Sheet 13 of 15
`
`6,023,961
`
`
`
`360
`
`Fig. 14
`
`Abbott
`Exhibit 1013
`Page 014
`
`

`

`U.S. Patent
`
`Feb. 15, 2000
`
`Sheet 14 of 15
`
`6,023,961
`
`START
`
`COLLECT CONDUCTIVITY DATA
`FROM TEMPERATURE DETECTOR
`
`DETERMINE POWER REOURED
`TO MANTAIN ARRAY AT
`PREDETERMINED OSCILLATION
`
`DETERMINE TEMPERATURE OF
`LUBRICANT
`
`436
`
`SSUE
`ALARM
`
`LUBRICANT TEMPERATURE
`SUITABLE
`
`DETERMINE ACTUAL WISCOSITY
`OF LUBRICANT USING
`POWER DATA
`
`440
`
`DETERMINE NORMATIVE WISCOSTY
`OF LUBRICANT USNG
`DATA TABLES AND MEASURED TEMP.
`
`MAKE HEALTH ASSESSMENT OF LUBRICANT
`BY CORRELATING ACTUAL VISCOSITY WITH
`NORMATIVE WISCOSTY
`
`444
`
`450
`
`Fig. 15
`
`480
`
`S
`LUBRICANT WISCOSITY
`SUTABLE
`
`
`
`
`
`NO
`
`ISSUE
`ALARM
`
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`OUTPUT
`STATUS/
`STORE DATA
`8, TIME
`
`Abbott
`Exhibit 1013
`Page 015
`
`

`

`
`
`
`
`
`
`
`
`U.S. Patent
`US. Patent
`
`Feb. 15, 2000
`
`Sheet 15 0f 15
`
`6,023,961
`6,023,961
`
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`
`Page 016
`
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`Exhibit 1013
`Page 016
`
`
`
`

`

`1
`MICRO-VISCOSITY SENSOR AND
`LUBRICATION ANALYSIS SYSTEM
`EMPLOYING THE SAME
`
`TECHNICAL FIELD
`The present invention generally relates to a micro electro
`mechanical Viscosity Sensor.
`BACKGROUND OF THE INVENTION
`Dynamoelectric machines Such as motors and generators
`and other rotating machines Such as gears and bearing
`Systems are widely employed in industrial and commercial
`facilities. These machines are relied upon to operate with
`minimal attention and provide for long, reliable operation.
`Many facilities operate Several hundreds or even thousands
`of Such machines concurrently, many of which are integrated
`into a large interdependent proceSS or System. Like most
`machinery, at least a Small percentage of Such equipment is
`prone to failure. Some of such failures can be attributed to
`loSS of lubrication, incorrect lubrication, lubrication break
`down or lubrication contamination.
`Depending on the application, the failure of a machine in
`Service can possibly lead to System or process down time,
`inconvenience, material Scrap, hazardous material cleanup
`and possibly even a dangerous situation. Thus, it is desirable
`to diagnose the machinery for possible failure or faults early
`in order to take preventive action and avoid Such problems.
`Absent Special monitoring for certain lubrication problems,
`the problem may have an insidious effect in that although
`only a minor problem on the onset the problem could
`become Serious if not detected. For example, bearing prob
`lems due to inadequate lubrication, lubrication contamina
`tion or other causes may not become apparent until irrevers
`ible damage has occurred.
`Proper lubrication facilitates the extension of machinery
`life. For example when motor lubrication is continuously
`exposed to high temperatures, high Speeds, StreSS or loads,
`and an oxidizing environment, the lubrication will deterio
`rate and lose its lubricating effectiveness. The loss of lubri
`cating effectiveness will affect two main functions of a
`lubrication System, namely: (1) to reduce friction; and (2) to
`remove heat. Continued operation of Such a degraded SyS
`tem will result in even greater heat generation and acceler
`ated System degradation. To protect the motor, the lubrica
`tion should be changed in a timely fashion. However, a
`balance must be struck-on one hand it is undesirable to
`replace an adequate lubricant, but on the other hand it is
`desired to replace a lubricant that is in its initial Stages of
`breakdown or contamination before equipment damage
`occurs. Since each particular application of a lubricant is
`relatively unique with respect to when the lubricant will
`breakdown or possibly become contaminated, it becomes
`necessary to monitor the lubricant.
`Various techniques for analyzing lubricants are known.
`For example, measuring a dielectric constant change in the
`lubricant or recording a thermal history of the lubricant have
`been employed for monitoring the lubricant's condition.
`However, these methods require the use of the same lubri
`cant or assume no machinery malfunctions throughout the
`measurements. Furthermore, these monitoring techniques
`typically require that a Sample of the lubrication be extracted
`and analyzed using laboratory grade equipment to determine
`the condition of the lubricant.
`Using two-electrode type Sensors to measure conductivity
`changes has been tried. The Selectivity of Such Sensors is
`generally not sufficient to differentiate between a new lubri
`
`15
`
`25
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`35
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`40
`
`45
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`50
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`55
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`60
`
`65
`
`6,023,961
`
`2
`cant and deteriorated used lubricant. This is because current
`collected from measuring both new and used lubricants is
`high. Consequently, it is often difficult for Such Sensors to
`distinguish between new and degraded lubricants because all
`electroactive Species are collected with near equal efficiency.
`Furthermore, it is known that the dielectric constant of
`different brands of lubricants differ from each other.
`Therefore, it is difficult to find a dielectric constant value at
`which all brands of lubricants are definitely bad.
`In view of the above, there is a need for an improved
`Sensor for detecting a health condition of a lubricant.
`SUMMARY OF THE INVENTION
`The present invention relates to a microfabricated Viscos
`ity Sensor. In particular, the present invention relates to a
`viscosity sensor of a MEMS (micro-electro mechanical
`Systems) type. The Viscosity Sensor is made using integrated
`circuit-like microfabrication techniques (e.g., Silicon based
`fabrication techniques). As a result, the Viscosity sensor of
`the present invention provides for Substantial advantages in
`terms of performance, reduced size, weight and costs
`especially since the wafer level technology employed
`affords for automated and batch production of numerous
`Viscosity Sensors on a single wafer.
`The Viscosity Sensor includes a plurality (e.g., array) of
`finger-like elements (e.g., cilia) which are plated with an
`electrically conductive material. The finger-like elements
`extend perpendicularly from the Surface of the Sensor, and
`the Sensor functions based on the phenomena that a dissi
`pative or damping force that resists the motion of the
`energized finger-like elements results in an increased power
`demand to maintain oscillation of the finger-like elements at
`a particular frequency. A lubricant of high Viscosity will
`exert a greater damping force on the oscillating finger-like
`elements than a lubricant of lower Viscosity. As a result,
`more power is required to maintain oscillation of the finger
`like elements at a particular frequency in a high Viscosity
`lubricant than a lubricant of lower viscosity. Thus, the
`viscosity of a fluid may be determined via the micro vis
`cosity Sensor of the present invention by monitoring the
`power required to oscillate the finger-like elements at a
`particular frequency and/or range of frequencies. Since the
`Viscosity of a lubricant is also a function of lubricant
`temperature (e.g., typically, the higher the lubricant tem
`perature the lower the lubricant Viscosity), the present inven
`tion also employs a temperature detector to correlate the
`temperature of the lubricant with the aforementioned power
`requirements to accurately interpret lubricant Viscosity.
`The employment of MEMS technology in the fabrication
`of the Viscosity Sensor provides for forming a three
`dimensional Sensor including an array of finger-like ele
`ments as compared to a single element. The array of finger
`like elements affords increased reliability and sensitivity of
`the Viscosity Sensor because of the extended Sensing area in
`contact with the fluid being analyzed. Moreover, the plural
`ity of finger-like elements provides for good resolution of
`power demand needed to oscillate the finger-like elements at
`a particular frequency.
`Additionally, the Viscosity Sensor includes a temperature
`detector for measuring the temperature of the lubricant.
`Knowledge of the temperature of the lubricant facilitates
`interpretation of the measured lubricant Viscosity. A lubri
`cant analyzer is operatively coupled to the Viscosity Sensor
`and provides for determining a health State of the lubricant.
`The lubricant analyzer employs data (e.g., temperature,
`oscillation frequency, power draw, Voltage Signature, current
`
`Abbott
`Exhibit 1013
`Page 017
`
`

`

`3
`Signature) provided by the Viscosity sensor to determine the
`health state of the fluid. More particularly, the data taken
`alone or in combination will correspond to a particular
`viscosity and/or health state of the lubricant. The lubricant
`analyzer compares a current Set of data to a known Set of
`historical and normative data relating to the condition of the
`lubricant in order to assess the present condition of the
`lubricant.
`In accordance with one aspect of the present invention, a
`micro-Viscosity Sensor for Sensing the Viscosity of a fluid
`includes at least one Sensing element exposed to the fluid,
`the at least one Sensing element adapted to be oscillated over
`a range of frequencies, wherein the Viscosity of the fluid is
`determined as a function of the power required to maintain
`oscillation of the at least one Sensing element at a predeter
`mined frequency.
`In accordance with another aspect of the present
`invention, a lubricant analysis System includes at least one
`micro-Viscosity Sensor which includes an array offinger-like
`elements extending perpendicular to the Surface of a Semi
`conductor base, the array of finger-like elements being
`oscillated at a predetermined frequency, wherein the power
`required to maintain oscillation of the array of finger-like
`elements at the pre-determined frequency corresponds to the
`viscosity of the fluid. The system also includes a lubrication
`analyzer which includes a processor operatively coupled to
`the at least one micro-Viscosity Sensor, the processor adapted
`to proceSS data output from the at least one micro-Viscosity
`sensor to determine the viscosity of the fluid.
`Another aspect of the present invention relates to a
`method for fabricating a micro-Viscosity Sensor, including
`etching a Semiconductor Substrate to form an array of
`finger-like elements which extend perpendicularly from a
`base of the Substrate, the array of finger-like elements
`adapted to oscillate over a range of frequencies, wherein the
`power required to maintain oscillation of the array of
`finger-like elements at a particular frequency corresponds to
`the Viscosity of a fluid being Sensed.
`Yet another aspect of the present invention provides for a
`micro-Viscosity Sensor for measuring the Viscosity of a
`lubricant including at least one finger-like element extending
`from the Surface of a Semiconductor base, the at least one
`finger-like element operative to be oscillated over a range of
`frequencies. The micro-Viscosity also includes a temperature
`detector, wherein the conductivity of the temperature detec
`tor varies in correspondence with the temperature of the
`lubricant. A first Set of electrical contacts provides electrical
`connection to the at least one finger-like element; and a
`Second Set of electrical contacts provides electrical connec
`tion to the temperature detector.
`Another aspect of the present invention is a method for
`Sensing the Viscosity of a fluid including the Steps of:
`oscillating at least one element extending from the Surface of
`a Semiconductor base, the at least one element operative to
`be oscillated over a range of frequencies, using a tempera
`ture detector to measure the temperature of the fluid,
`wherein the conductivity of the temperature detector varies
`in correspondence with the temperature of the lubricant; and
`determining the power required to maintain oscillation of the
`at least one element at a particular frequency, the particular
`frequency being different than a natural resonant frequency
`of the at least one element, wherein the power required is a
`function of the viscosity of the fluid.
`Still another aspect of the present invention provides for
`a Viscosity Sensing System which includes at least one
`micro-Viscosity Sensor. The micro-Viscosity Sensor includes
`
`15
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`35
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`6,023,961
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`4
`an array of elements extending from the Surface of a
`Semiconductor base, the array of elements being oscillated at
`a pre-determined frequency, wherein the power required to
`maintain oscillation of the array of finger-like elements at
`the pre-determined frequency corresponds to the Viscosity of
`the fluid. The Viscosity Sensing System also includes a
`lubrication analyzer including a processor operatively
`coupled to the at least one micro-Viscosity Sensor, the
`processor adapted to process data output from the at least
`one micro-Viscosity Sensor to determine the Viscosity of the
`fluid. The integrated Viscosity Sensing System provides for in
`Situ monitoring of the fluid.
`To the accomplishment of the foregoing and related ends,
`the invention, then, comprises the features hereinafter fully
`described and particularly pointed out in the claims. The
`following description and the annexed drawings Set forth in
`detail certain illustrative embodiments of the invention.
`These embodiments are indicative, however, of but a few of
`the various ways in which the principles of the invention
`may be employed. Other objects, advantages and novel
`features of the invention will become apparent from the
`following detailed description of the invention when con
`sidered in conjunction with the drawings.
`BRIEF DESCRIPTION OF THE DRAWINGS
`FIG. 1 is a perspective illustration of a Viscosity Sensor in
`accordance with one embodiment of the present invention;
`FIG. 2 is a functional Schematic diagram of an integrated
`AC induction motor and lubricant analyzer employing the
`viscosity sensor of FIG. 1 in accordance with one embodi
`ment of the present invention;
`FIG. 3 is a block diagram of a Viscosity Sensor and
`lubricant analyzer in accordance with one embodiment of
`the present invention;
`FIG. 4a is a graphical illustration of an input signal for
`oscillating an array of finger-like elements in a high ViscoS
`ity fluid in accordance with one embodiment of the present
`invention;
`FIG. 4b is a graphical illustration of an input signal for
`oscillating an array of finger-like elements in a low Viscosity
`fluid in accordance with one embodiment of the present
`invention;
`FIG. 4c is a graphical illustration of a control Signal and
`an output Signal from a Viscosity Sensor exposed to a high
`Viscosity lubricant in accordance with one embodiment of
`the present invention;
`FIG. 5a is a table diagram of Viscosity Sensor input signal
`Signatures over a range of temperatures and frequencies,
`which may be used to facilitate diagnosing the health State
`of a lubricant in accordance with one embodiment of the
`present invention;
`FIG.5b is a representative table diagram of fluid viscosity
`health States based upon actual power requirements to
`maintain oscillation of an array of finger-like elements at a
`particular frequency at particular temperatures,
`FIG. 6a is a functional Schematic diagram a motor bearing
`lubricant diagnostic System in accordance with one embodi
`ment of the present invention;
`FIG. 6b is a functional schematic diagram of a motor
`bearing lubricant diagnostic System in accordance with
`another embodiment of the present invention;
`FIG. 6c is a functional Schematic diagram of a lubricant
`diagnostic System for diagnosing the Viscosity of lubricants
`for a plurality of machines in accordance with another
`embodiment of the present invention;
`
`Abbott
`Exhibit 1013
`Page 018
`
`

`

`6,023,961
`
`S
`FIG. 7 is a perspective illustration of a silicon substrate
`being etched to form an array of finger-like elements in
`accordance with one embodiment of the present invention;
`FIG. 8 is a perspective illustration of the silicon substrate
`of FIG. 7 after the etching step to form an array of finger-like
`elements in accordance with one embodiment of the present
`invention;
`FIG. 9 is a perspective illustration of the substrate of FIG.
`8 being masked, etched and patterned to form electrical
`contacts and electrical pathways in accordance with one
`embodiment of the present invention;
`FIG. 10 is a perspective illustration of the Substrate of
`FIG. 9 being masked, etched and patterned to form a
`temperature detector in accordance with one embodiment of
`the present invention;
`FIG. 11 is a perspective illustration of the array of
`finger-like elements of FIG. 10 being seeded with a seed
`material in accordance with one embodiment of the present
`invention;
`FIG. 12 is a perspective illustration of the array of
`finger-like elements of FIG. 11 being plated with an inert
`conductive material in accordance with one embodiment of
`the present invention;
`FIG. 13 is a front view of a viscosity sensor in accordance
`with another embodiment of the present invention; and
`FIG. 14 is a perspective view of yet another viscosity
`Sensor in accordance with an embodiment of the present
`invention;
`FIG. 15 is a flow diagram illustrating one methodology
`for carrying out the present invention; and
`FIG. 16 is a Schematic block diagram of an integrated
`Viscosity Sensing System in accordance with the present
`invention.
`
`DETAILED DESCRIPTION OF THE
`INVENTION
`The present invention will now be described with refer
`ence to the drawings, wherein like reference numerals are
`used to refer to like elements throughout.
`AS is mentioned above, the present invention relates to a
`MEMS-type viscosity sensor which includes a plurality of
`finger-like elements (e.g., cilia). The plurality of finger-like
`elements are oscillated at a fixed frequency, and the power
`required to drive Such oscillation corresponds to the ViscoS
`ity of a lubricant the Sensor is in contact with.
`Referring initially to FIG. 1 an exemplary viscosity sensor
`20 in accordance with the present invention is shown in
`perspective view. The Viscosity Sensor 20 includes a Semi
`conductor base 24 which preferably comprises Silicon,
`however, any Suitable material may be employed. Protrud
`ing perpendicularly from the base 24 is an array of finger
`like elements 30 which may be the same material as the base
`24. As will be discussed in greater detail below, the base 24
`and the array of finger-like elements 30 are formed by
`etching a Semiconductor Substrate material. The array of
`finger-like elements 30 are designed to extend into and be
`coated by the lubricant that is being measured. The finger
`like elements 30 will be damped by the lubricant as a
`function of the Viscosity of the lubricant. Accordingly, Such
`damping effect will influence the amount of power required
`to oscillate the finger-like elements 30 at a desired fre
`quency.
`The lubricant creates a dissipative or damping force that
`resists the motion of the energized finger-like elements.
`Thus, the higher the viscosity of the lubricant the more
`
`6
`power that is required to oscillate the finger-like elements at
`a particular frequency. AS will be discussed in greater detail
`below, by monitoring the power required to oscillate the
`finger-like elements at a particular frequency, the particular
`frequency being different than a natural resonant frequency
`of the finger-like elements, and employing other interpretive
`parameters (e.g., temperature) the Viscosity and/or health
`state of the lubricant can be determined.
`The Viscosity Sensor 20 includes a temperature detector
`40 located on the Surface of the base 24. The temperature
`detector 40 is preferably formed from platinum, however, it
`is to be appreciated that any material (e.g., gold) Suitable for
`carrying out the present invention may be employed. The
`temperature detector 40 is patterned on the base in accor
`dance with a predetermined length, width and Surface area.
`Therefore, by knowing the Surface area of the temperature
`detector and the material of which it is made, a temperature
`of a lubricant to which the temperature sensor 40 is exposed
`may be determined based on the electrical conductivity of
`the temperature detector 40. Knowledge of the lubricant
`temperature is useful in interpreting the Viscosity of the
`lubricant being analyzed because lubricant Viscosity is a
`function of lubricant temperature. In general, the higher is
`the lubricant temperature, the lower is the lubricant ViscoS
`ity. However, Some lubrication problems (e.g., water
`contamination) may result in a different lubricant Viscosity
`at the measured temperature than the Viscosity expected in
`fresh, healthy lubrication. The present invention correlates
`lubricant temperature with the power required to oscillate
`the array of finger-like elements 30 at a desired frequency to
`establish the health of the lubrication.
`A Set of electrical contacts 44a and 44b are patterned on
`the base 24 and are bonded to a conductive plating (FIGS.
`11-12) coating and connect the array of finger-like elements
`30 via conductive pathways 52. In particular, the array of
`finger-like elements 30 are plated (e.g., electroplated) with
`an inert conductive material Such as nickel or the like. The
`plating Serves to electrically couple each of the finger-like
`elements to one another. The electrical contacts 44a and 44b
`provide for electrical connection to the array of finger-like
`elements 30 for OScillating the finger-like elements at a
`desired frequency. Electrical contact 44a is coupled to a
`finger-like element 50a at one end of the array 30 via a
`conductor 52a. Electrical contact 44b is coupled to a finger
`like element 50b at the other end of the array 30 via a
`conductor 52b.
`Another set of electrical contacts 60a and 60b patterned
`on the base are coupled via the conductive pathways 52c and
`52d to the temperature detector 40.
`The Viscosity Sensor 20 is Small having a Square area of
`approximately 4 mm. Accordingly, the Viscosity Sensor 20 is
`desirable for use in applications where Space is at a premium
`but where accuracy, reliability, and Sensitivity of measured
`data are also at a premium. Furthermore, because the vis
`cosity Sensor 20 is fabricated in accordance with integrated
`circuit-like fabrication techniques, large batches of the Sen
`sors 20 may be easily and efficiently produced with good
`production yields.
`It is to be appreciated that a mirror Set of temperature
`detector, array of finger-like elements and electrical contacts
`may be formed on the other side of the base 24 so as to
`increase the functionality of the viscosity sensor 20 (See
`FIG. 13).
`Turning now to FIG. 2, an exemplary environment in
`which the present invention may be employed is shown. A
`three-phase AC induction motor 70 is depicted driving a
`
`15
`
`25
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`Abbott
`Exhibit 1013
`Page 019
`
`

`

`7
`load 72 through a shaft coupling 74. The motor 70 includes
`a junction box 76 for receiving conductors from power lines
`via a conduit 78, which are tied to power supply lines (not
`shown) of the motor 70. The motor 70 is AC powered and
`operates at an AC power line frequency of 60 Hz. However,
`it is appreciated that different line frequencies (e.g., 50 Hz)
`may be employed. Coupled to the motor 70 is a lubricant
`analyzer 90 (FIG. 3) which as will be discussed in greater
`detail below provides for receiving and processing data
`relating to the health of lubricant employed by the motor 70.
`The lubricant analyzer 90 includes a display 92 for
`displaying to an operator information relating to the health
`of the lubricant. It is to be appreciated that the lubricant
`analyzer 90 may also perform other functions relating to
`determining the health of the motor 70 (e.g., current signa
`ture analysis, vibration analysis, etc.). The lubricant analyzer
`90 further includes an operator input device 98 in the form
`of a key pad which enables a user to enter data, information,
`function commands, etc. as is conventional. For example,
`the user may input information relating to lubricant type via
`the keypad 98 for Subsequent transmission to a host com
`puter 102. In addition, the keypad 98 may include up and
`down cursor keys for controlling a cursor which may be
`shown on the display 92. The lubricant analyzer 90 includes
`a communications port 106 for interfacing the lubricant
`analyzer 90 with the viscosity sensor 20 (FIG. 3) and the
`host computer 102 via a Suitable communications link.
`According to an embodiment of the present invention, the
`lubricant analyzer 90 is part of a communication system
`including a network backbone 120. The network backbone
`120 may be a hardwired data communication path made of
`twisted pair cable, Shielded coaxial cable or fiber optic cable,
`for example, or may be wireless or partially wireless in
`nature. Information is transmitted via the network backbone
`120 between the host computer 102 and the lubricant
`analyzer 90. The communication link preferably adheres to
`the RS232C or DeviceNet standard for communicating
`command and parameter information. However, any com
`munication link Suitable for carrying out the present inven
`40
`tion may be employed.
`Referring now in particular to FIG. 3, a Schematic repre
`Sentation of the present invention is shown according to one
`particular aspect of the present invention, wherein the lubri
`cant analyzer 90 is integrated with the viscosity sensor 20.
`However, it will be appreciated from the discussion herein
`that the lubricant analyzer 90 may be located remotely from
`the motor 70. Furthermore, it is to be appreciated that the
`host computer may serve to carry out Substantially all of the
`functions described herein performed by the lubricant ana
`lyzer 90. It is also to be appreciated that in accordance with
`ano