US5731876A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for on-line determination of the thickness of a multilayer film using a partially reflecting roller and low coherence reflectometry
Assignee: Agilent Technologies Inc
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Filing: 1996-09-17
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Granted: 1998-03-24
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Expires: 2016-09-17
Abstract
Abstract An apparatus and method for measuring the thickness of a film having top and bottom surfaces. The apparatus includes low coherence light source that generates a probe light signal. The film is positioned against a roller having a partially reflecting surface that is positioned at a fixed distance from the film. The probe light signal is applied to the film and is then reflected back through the film by the partially reflecting surface. The light leaving the film is collected to form the input to a receiver that determines the time delay between light reflected from the top and bottom surfaces of the film. The receiver output may also be used to determine the thickness of the various layers in a multi-layer film.
Inventors
- 👤 Shalini Venkatesh
- 👤 Brian L. Heffner
- 👤 Wayne V. Sorin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 08:06
CPC Classifications
G; G01; G01B; G01B11/00; G01B11/02; G01B11/06; G01B11/0616; G01B11/0675
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
102 words
An apparatus for measuring the thickness of a transparent film having top and bottom surfaces, said apparatus comprising: means for generating a probe light signal from a low coherence light source and applying said probe light signal to said film; a roller having a partially reflecting surface and means for positioning said film at a fixed distance from said reflecting surface; means for collecting light reflected back from said partially reflecting surface; and a receiver for receiving said collected light and for determining the time delay between light reflected from said top and bottom surfaces of said film from said collected light.
Claim 2
Independent Claim
102 words
An apparatus for measuring the thickness of a transparent film having top and bottom surfaces, said apparatus comprising: means for generating a probe light signal from a low coherence light source and applying said probe light signal to said film; a roller having a partially reflecting surface and means for positioning said film at a fixed distance from said reflecting surface; means for collecting light reflected back from said partially reflecting surface; and a receiver for receiving said collected light and for determining the time delay between light reflected from said top and bottom surfaces of said film from said collected light.
Claim 3
Dependent Claim
12 words
The apparatus of claim 1 wherein said receiver comprises an optical autocorrelator.
Claim 4
Dependent Claim
12 words
The apparatus of claim 1 wherein said receiver comprises an optical reflectometer.
Claim 5
Dependent Claim
13 words
The apparatus of claim 1 wherein said receiver comprises an optical spectrum analyzer.
Claim 6
Dependent Claim
19 words
The apparatus of claim 1 wherein means for positioning said film comprises an optically transparent coating on said roller.
Claim 7
Dependent Claim
28 words
The apparatus of claim 5 wherein said roller comprises first and second regions and wherein said optically transparent coating has different thicknesses in said first and second regions.
Claim 8
Dependent Claim
39 words
The apparatus of claim 1 wherein said film comprises a plurality of layers and wherein said receiver determines the time delay between light reflected from said partially reflecting surface and at least one boundary between two of said layers.
Claim 9
Independent Claim
99 words
A method for measuring the thickness of a transparent film having top and bottom surfaces, said method comprising the steps of: generating a probe light signal from a low coherence light source and applying said probe light signal to said film; providing a roller having a partially reflecting surface and means for positioning said film at a fixed distance from said partially reflecting surface; collecting light reflected by said film and said partially reflecting surface; and determining the time delay between light reflected from said top and bottom surfaces of said film from said collected light in a receiver.
Claim 10
Independent Claim
99 words
A method for measuring the thickness of a transparent film having top and bottom surfaces, said method comprising the steps of: generating a probe light signal from a low coherence light source and applying said probe light signal to said film; providing a roller having a partially reflecting surface and means for positioning said film at a fixed distance from said partially reflecting surface; collecting light reflected by said film and said partially reflecting surface; and determining the time delay between light reflected from said top and bottom surfaces of said film from said collected light in a receiver.
Claim 11
Dependent Claim
12 words
The method of claim 8 wherein said receiver comprises an optical autocorrelator.
Claim 12
Dependent Claim
12 words
The method of claim 8 wherein said receiver comprises an optical reflectometer.
Claim 13
Dependent Claim
13 words
The method of claim 8 wherein said receiver comprises an optical spectrum analyzer.
Claim 14
Dependent Claim
19 words
The method of claim 8 wherein means for positioning said film comprises an optically transparent coating on said roller.
Claim 15
Dependent Claim
28 words
The method of claim 12 wherein said roller comprises first and second regions and wherein said optically transparent coating has different thicknesses in said first and second regions.
Claim 16
Dependent Claim
44 words
The method of claim 1 wherein said film comprises a plurality of layers and wherein said method further comprises the step of determining the time delay between light reflected from said partially reflecting surface and at least one boundary between two of said layers.
References Cited (Backward Citations)
US3982816A
Cited
US5473432A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-03-23 | 2001-09-22 | 2002-03-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-03-23 | 2005-09-22 | 2006-03-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-03-23 | 2009-09-22 | 2010-03-24 | $7700.00 | Window Closed / Lapsed |