US4956558A
Expired / Lapsed
US
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System for measuring film thickness
Assignee: Battelle Memorial Institute Inc
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Filing: 1989-03-16
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Granted: 1990-09-11
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Expires: 2009-03-16
Abstract
Abstract A system for determining the thicknesses of thin films of materials exhibiting fluorescence in response to exposure to excitation energy from a suitable source of such energy. A section of film is illuminated with a fixed level of excitation energy from a source such as an argon ion laser emitting blue-green light. The amount of fluorescent light produced by the film over a limited area within the section so illuminated is then measured using a detector such as a photomultiplier tube. Since the amount of fluorescent light produced is a function of the thicknesses of thin films, the thickness of a specific film can be determined by comparing the intensity of fluorescent light produced by this film with the intensity of light produced by similar films of known thicknesses in response to the same amount of excitation energy. The preferred embodiment of the invention uses fiber optic probes in measuring the thicknesses of oil films on the operational components of machinery which are ordinarily obscured from view.
Inventors
- 👤 Charles R. Batishko
- 👤 Leslie J. Kirihara
- 👤 Timothy J. Peters
- 👤 Donald E. Rasmussen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 17:21
CPC Classifications
G; G01; G01B; G01B11/00; G01B11/02; G01B11/06; G01B11/0616; G01B11/0658; F; F16; F16N; F16N29/00
Claims Analysis
Total Claims: 32
Claim 1
Independent Claim
99 words
A method for measuring the thickness of a thin film of material on a surface of a body, said film having fluorescent properties, comprising the steps of: illuminating a section of said film with excitation energy suitable for stimulating fluorescence in the material of the film; measuring from within said body underneath the surface upon which said film resides the intensity of the fluorescent light produced over a limited area within said section of film; and correlating said intensity with the intensities of fluorescent light produced by established film thicknesses in order to determine the thickness of said film.
Claim 2
Independent Claim
99 words
A method for measuring the thickness of a thin film of material on a surface of a body, said film having fluorescent properties, comprising the steps of: illuminating a section of said film with excitation energy suitable for stimulating fluorescence in the material of the film; measuring from within said body underneath the surface upon which said film resides the intensity of the fluorescent light produced over a limited area within said section of film; and correlating said intensity with the intensities of fluorescent light produced by established film thicknesses in order to determine the thickness of said film.
Claim 3
Dependent Claim
55 words
The method of claim 1, wherein said step of measuring the intensity of said fluorescent light includes the steps of: filtering the light from said film so as to pass only the long-wave components thereof; and detecting the amount of longer wavelength light generated by said area of said film in accordance with fluorescent effects.
Claim 4
Dependent Claim
54 words
The method of claim 1 wherein said step of illuminating said film includes the steps of: generating light with a mercury arc lamp; filtering this light so as to pass only the short-wave components thereof; and directing the high frequency light produced in accordance with said filtering step at said section of said film.
Claim 5
Dependent Claim
23 words
The method of claim 1 wherein said film of material comprises a layer of lubricating oil and said excitation energy comprises blue-green light.
Claim 6
Dependent Claim
22 words
The method of claim 1 wherein said film of material contains a fluorescent dye suitable for inducing fluorescent properties in the film.
Claim 7
Dependent Claim
29 words
The apparatus according to claim 1 wherein the step of measuring is accomplished via a fiber optic element extending in substantially flush relation to said surface and said film.
Claim 8
Dependent Claim
28 words
The method of claim 1 wherein the step of illuminating said film comprises: generating light with a laser, and directing the generated light at said section of film.
Claim 9
Independent Claim
95 words
An apparatus for measuring the thickness of a thin film of material having fluorescent properties on a surface of a body wherein said surface cannot be directly observed, comprising: a source of excitation energy suitable for stimulating fluorescence in the material of the film; detection means for measuring fluorescent light intensity; a fiber optic probe mounted within said body and extending to said surface, said probe being connected to said detection means for transmitting fluorescent light from said surface to; and means coupled to said detection means for providing an output responsive to film thickness.
Claim 10
Independent Claim
95 words
An apparatus for measuring the thickness of a thin film of material having fluorescent properties on a surface of a body wherein said surface cannot be directly observed, comprising: a source of excitation energy suitable for stimulating fluorescence in the material of the film; detection means for measuring fluorescent light intensity; a fiber optic probe mounted within said body and extending to said surface, said probe being connected to said detection means for transmitting fluorescent light from said surface to; and means coupled to said detection means for providing an output responsive to film thickness.
Claim 11
Dependent Claim
16 words
The apparatus of claim 8 wherein said fiber optic probe comprises a single fiber optical element.
Claim 12
Dependent Claim
28 words
The apparatus of claim 9 wherein the end of said fiber optical probe element proximate said surface is flush with said surface wherein said thin film extends thereover.
Claim 13
Dependent Claim
18 words
The apparatus of claim 8 wherein said light source includes an ragon ion laser which emits blue-green light.
Claim 14
Dependent Claim
41 words
The apparatus of claim 8 wherein said detection means for detecting fluorescent light includes: means for filtering the light from said film so as to only pass the long wave components thereof; and a photomultiplier tube responsive to the fluorescent light.
Claim 15
Dependent Claim
31 words
The apparatus of claim 8 wherein said thin film of material comprises a layer of lubricating oil and said excitation energy comprises blue-green light having a wavelength of approximately 488 nm.
Claim 16
Dependent Claim
17 words
The apparatus of claim 13 wherein said body comprises the chain bar rail of a chain saw.
Claim 17
Dependent Claim
25 words
The apparatus of claim 8 wherein said probe is also coupled to said light source for transmitting excitation energy from said source to said surface.
Claim 18
Dependent Claim
32 words
The apparatus of claim 8 including a second fiber optic probe mounted in said body and extending to said light excitation source for transmitting excitation energy from said source to said surface.
Claim 19
Dependent Claim
17 words
The apparatus of claim 16 wherein said second fiber optic probe comprises a single fiber optical element.
Claim 20
Dependent Claim
23 words
The apparatus of claim 16 wherein said second fiber optic probe is disposed at an angle to the first mentioned fiber optic probe.
Claim 21
Dependent Claim
30 words
The apparatus of claim 8 wherein said source of excitation energy includes: a source of ultraviolet light; and means for directing said ultraviolet light at said section of said film.
Claim 22
Dependent Claim
22 words
The apparatus of claim 19 wherein said source of ultraviolet light comprises a mercury arc lamp and a short-wave pass light filter.
Claim 23
Dependent Claim
19 words
The apparatus of claim 8 wherein said film of material comprises lubricating oil and said energy comprises blue-green light.
Claim 24
Dependent Claim
22 words
The apparatus of claim 8 wherein said film of material contains a fluorescent dye suitable for inducing fluorescent properties in said film.
Claim 25
Independent Claim
107 words
An apparatus for measuring the thickness of a thin film of material having fluorescent properties on a surface of a body wherein said surface cannot be directly observed, comprising: a source of excitation energy suitable for stimulating fluorescence in the material of the film; detection means for measuring fluorescent light intensity; and a fiber optic probe mounted in said body and a extending to said surface, said probe containing a first set of fiber optic elements connected to said detection means for transmitting fluorescent light from said surface of said detection means; and means coupled to said detection means for providing an output responsive to film thickness.
Claim 26
Independent Claim
107 words
An apparatus for measuring the thickness of a thin film of material having fluorescent properties on a surface of a body wherein said surface cannot be directly observed, comprising: a source of excitation energy suitable for stimulating fluorescence in the material of the film; detection means for measuring fluorescent light intensity; and a fiber optic probe mounted in said body and a extending to said surface, said probe containing a first set of fiber optic elements connected to said detection means for transmitting fluorescent light from said surface of said detection means; and means coupled to said detection means for providing an output responsive to film thickness.
Claim 27
Dependent Claim
26 words
The apparatus of claim 23 wherein said energy source includes a mercury arc lamp and a short-wave pass filter which are operative for generating ultraviolet light.
Claim 28
Dependent Claim
38 words
The apparatus of claim 23 wherein said detection means for detecting fluorescent light includes: means for filtering the light from said film so as to pass the long-wave components thereof; and a photomultiplier tube responsive to fluorescent light.
Claim 29
Dependent Claim
17 words
The apparatus of claim 23 wherein said thin film of material comprises a layer of lubricating oil.
Claim 30
Dependent Claim
32 words
The apparatus of claim 23 wherein said probe also contains a second set of fiber optic elements connected to said energy source for transmitting excitation energy from said source to said surface.
Claim 31
Dependent Claim
25 words
The apparatus of claim 27 wherein the fiber optic elements of said second set are interspersed with the fiber optic elements of said first set.
Claim 32
Dependent Claim
12 words
The apparatus of claim 23 wherein said energy source comprises a laser.
References Cited (Backward Citations)
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