US4657736A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Sensor element for determining the oxygen content and a method of preparing the same
Assignee: Avl AG
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Filing: 1986-07-14
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Granted: 1987-04-14
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Expires: 2006-07-14
Abstract
Abstract In an O 2 sensor element which contains a fluorescent indicator substance, a polymerized silicone polymer is used as a carrier material in which the indicator substance is incorporated in solubilized form and in an at least approximately homogeneous distribution. Solubilization of the indicator substance may essentially be performed in analogy to Friedel-Crafts alkylation of aromatics, which will increase solubility of the indicator substance in the polymer carrier without affecting quenching behavior.
Inventors
- 👤 Hermann Marsoner
- 👤 Herbert Kroneis
- 👤 Otto Wolfbeis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 15:54
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/62; G01N21/63; G01N21/64; G01N21/6428; G01N21/643; C; C09; C09K; C09K11/00; C09K11/02; C09K11/025; C09K11/06; G01N21/645; G01N21/648; G01N21/75; G01N21/77; G01N21/7703; G01N2021/7706; G01N2021/773; G01N2021/7769; G01N2021/7786; Y; Y10; Y10T; Y10T436/00; Y10T436/20; Y10T436/207497
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
160 words
A sensor element which, when placed in contact with a sample containing oxygen, is capable of indicating the oxygen content in said sample, said sensor element comprising a cured silicone polymer carrier matrix which is permeable to oxygen molecules and a chemically modified, solubilized, oxygen-sensitive fluorescent indicator substance which is generally homogeneously embedded within said cured silicone polymer carrier matrix, said oxygen-sensitive fluorescent indicator substance, upon excitation, emitting light of a certain wavelength and of varying intensity depending on the amount of oxygen from said sample in contact therewith, said sensor element being produced by a method which comprises the steps of (a) combining an oxygen-sensitive fluorescent indicator substance with tertiary butyl chloride, (b) catalytically reacting said oxygen-sensitive fluorescent indicator substance and said tertiary butyl chloride and recovering a solubilized fluorescent indicator substance, (c) mixing said solubilized fluorescent indicator substance with an uncured silicone polymer to form a homogeneous mixture, and (d) curing said mixture to form said sensor element.
Claim 2
Dependent Claim
160 words
A sensor element which, when placed in contact with a sample containing oxygen, is capable of indicating the oxygen content in said sample, said sensor element comprising a cured silicone polymer carrier matrix which is permeable to oxygen molecules and a chemically modified, solubilized, oxygen-sensitive fluorescent indicator substance which is generally homogeneously embedded within said cured silicone polymer carrier matrix, said oxygen-sensitive fluorescent indicator substance, upon excitation, emitting light of a certain wavelength and of varying intensity depending on the amount of oxygen from said sample in contact therewith, said sensor element being produced by a method which comprises the steps of (a) combining an oxygen-sensitive fluorescent indicator substance with tertiary butyl chloride, (b) catalytically reacting said oxygen-sensitive fluorescent indicator substance and said tertiary butyl chloride and recovering a solubilized fluorescent indicator substance, (c) mixing said solubilized fluorescent indicator substance with an uncured silicone polymer to form a homogeneous mixture, and (d) curing said mixture to form said sensor element.
Claim 3
Dependent Claim
60 words
A sensor element according to claim 1, wherein said cured silicone polymer carrier matrix is shaped to include a flat surface which is intended to face the sample containing oxygen, and wherein said sensor element includes a polymer layer having low transparency covering said flat surface of said cured silicone polymer carrier, said polymer layer being permeable to oxygen molecules.
Claim 4
Dependent Claim
21 words
A sensor element according to claim 2, wherein said polymer layer comprises a silicone coating having particles of ferrous oxide therein.
Claim 5
Dependent Claim
50 words
A sensor element according to claim 1, wherein said cured silicone polymer carrier matrix is shaped to include a flat surface which is intended to face the sample containing oxygen, and wherein said cured silicone polymer carrier matrix includes a thin mesh screen embedded therein adjacent said flat surface thereof.
Claim 6
Dependent Claim
34 words
A sensor element according to claim 1, wherein said fluorescent indicator substance is a compound which includes molecules selected from the group consisting of polycyclic aromatic molecules, homocyclic aromatic molecules and heterocyclic aromatic molecules.
Claim 7
Dependent Claim
28 words
A sensor element according to claim 5, wherein said fluorescent indicator substance comprises a polycyclic aromatic hydrocarbon which displays fluorescence decay times τ o greater than 5 ns.
Claim 8
Dependent Claim
18 words
A sensor element according to claim 1, wherein said cured silicone polymer carrier matrix includes pigment particles therein.
Claim 9
Dependent Claim
15 words
A sensor element according to claim 7, wherein said pigment particles are ferrous oxide particles.
Claim 10
Dependent Claim
81 words
A sensor element according to claim 7, wherein said cured silicone polymer carrier matrix is generally plate shaped so as to have a first flat surface which is intended to face the sample containing oxygen and a second flat surface which is intended to face away from the sample containing oxygen, and wherein said pigment particles are contained in said cured silicone polymer carrier matrix in increasing amounts in the direction between said second flat surface and said first flat surface.
Claim 11
Dependent Claim
22 words
A sensor element according to claim 1, wherein said fluorescent indicator substance includes hydrocarbon chains containing between 3 and 20 carbons atoms.
Claim 12
Independent Claim
157 words
A method of producing a sensor element which, when placed in contact with a sample containing oxygen, is capable of indicating the oxygen content in said sample, said sensor element comprising a cured silicone polymer carrier matrix which is permeable to oxygen molecules and a chemically modified, solubilized, oxygen-sensitive fluorescent indicator substance which is generally homogeneously embedded within said cured silicone polymer carrier matrix, said oxygen-sensitive fluorescent indicator substance, upon excitation, emitting light of a certain wavelength and of varying intensity depending on the amount of oxygen from said sample in contact therewith, said method comprising the steps of (a) combining an oxygen-sensitive fluorescent indicator substance with tertiary butyl chloride, (b) catalytically reacting said oxygen-sensitive fluorescent indicator substance and said tertiary butyl chloride and recovering a solubilized fluorescent indicator substance, (c) mixing said solubilized fluorescent indicator substance with an uncured silicone polymer to form a homogeneous mixture, and (d) curing said mixture to form said sensor element.
Claim 13
Independent Claim
157 words
A method of producing a sensor element which, when placed in contact with a sample containing oxygen, is capable of indicating the oxygen content in said sample, said sensor element comprising a cured silicone polymer carrier matrix which is permeable to oxygen molecules and a chemically modified, solubilized, oxygen-sensitive fluorescent indicator substance which is generally homogeneously embedded within said cured silicone polymer carrier matrix, said oxygen-sensitive fluorescent indicator substance, upon excitation, emitting light of a certain wavelength and of varying intensity depending on the amount of oxygen from said sample in contact therewith, said method comprising the steps of (a) combining an oxygen-sensitive fluorescent indicator substance with tertiary butyl chloride, (b) catalytically reacting said oxygen-sensitive fluorescent indicator substance and said tertiary butyl chloride and recovering a solubilized fluorescent indicator substance, (c) mixing said solubilized fluorescent indicator substance with an uncured silicone polymer to form a homogeneous mixture, and (d) curing said mixture to form said sensor element.
Claim 14
Dependent Claim
25 words
A method according to claim 11, wherein in step (a) said oxygen-sensitive fluorescent indicator substance and said tertiary butyl chloride are dissolved in a solvent.
Claim 15
Dependent Claim
14 words
A method according to claim 12, wherein said solvent consists of CS 2 .
Claim 16
Dependent Claim
28 words
A method according to claim 11, wherein in step (b) said oxygen-sensitive fluorescent indicator substance and said tertiary butyl chloride are reacted in the presence of aluminum chloride.
Claim 17
Dependent Claim
24 words
A method according to claim 11, wherein in step (a) said oxygen-sensitive fluorescent indicator substance is dissolved in an excess of tertiary butyl chloride.
Claim 18
Dependent Claim
19 words
A method according to claim 11, including between steps (c) and (d) the step (c') of moulding said mixture.
Claim 19
Dependent Claim
22 words
A method according to claim 16, wherein in step (c') said mixture is moulded into the general form of a flat plate.
Claim 20
Dependent Claim
58 words
A method according to claim 16, including between steps (c) and (c') the step (c") of adding ferrous oxide particles to said mixture, and between steps (c") and (c') the step (c'") of applying a force field to said moulded mixture so as to cause said ferrous oxide particles to be graded in amount through said moulded mixture.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-04-13 | 1990-10-13 | 1991-04-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-04-13 | 1994-10-13 | 1995-04-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-04-13 | 1998-10-13 | 1999-04-14 | $7700.00 | Window Closed / Lapsed |