Luminescence monitoring with modulation frequency multiplexing
First Claim
1. A probe for monitoring a plurality of conditions comprising:
- (a) a light-transmissive member for applying excitation light within a common band of excitation wavelengths;
(b) luminescent means connected to said member in optical communication therewith, said luminescent means having a plurality of emission modes with different lifetimes, said luminescent means being operative to simultaneously emit a plurality of response light signals having wavelengths within a common band of response wavelengths into said light-transmissive member in response to the excitation light within the common band of excitation wavelengths applied through said light-transmissive member, each such response light signal representing one said emission mode, said luminescent means being operative to vary each of said lifetimes in response to one of said conditions to be monitored.
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Abstract
A luminescence based analytical probe is excited with light varying repetitively in amplitude at multiple modulation frequencies. A composite signal incorporating components at a plurality of these modulation frequencies, produced by emissions in all of the various decaying modes is analyzed to provide information, such as the fractional luminescence contribution and/or lifetime of each individual decaying mode because the various decaying mode are segregated by analysis of the composite signal, there is no need to segregate light from the various decaying mode according to the wavelength of the light. Therefore, the probe may incorporate plural luminescent materials which have different decay modes with different luminescent decay times and sensitive to different conditions to be monitored, even if the plural luminescent materials absorb and emit light at the same wavelengths.
102 Citations
21 Claims
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1. A probe for monitoring a plurality of conditions comprising:
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(a) a light-transmissive member for applying excitation light within a common band of excitation wavelengths; (b) luminescent means connected to said member in optical communication therewith, said luminescent means having a plurality of emission modes with different lifetimes, said luminescent means being operative to simultaneously emit a plurality of response light signals having wavelengths within a common band of response wavelengths into said light-transmissive member in response to the excitation light within the common band of excitation wavelengths applied through said light-transmissive member, each such response light signal representing one said emission mode, said luminescent means being operative to vary each of said lifetimes in response to one of said conditions to be monitored. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. Apparatus for monitoring a plurality of conditions comprising
(a) a light-transmissive member; -
(b) luminescent means for emitting response light connected to said member in optical communication therewith, said luminescent means having a plurality of emission modes with different lifetimes, said luminescent means being operative to vary each of said lifetimes in response to one of said conditions to be monitored; (c) excitation light source means for simultaneously applying a plurality of excitation light components varying cyclically in amplitude at a plurality of modulation frequencies to said luminescent means through said light transmissive member so that said luminescent means emits response light simultaneously incorporating a plurality of response light components each varying cyclically in amplitude at one of said modulation frequencies and so that said response light components cooperatively represent all of said plurality of emission modes of said luminescent means; (d) transducer means for deriving a multicomponent response signal incorporating components corresponding to a plurality of said modulation frequencies from said response light so that said multicomponent response signal represents a plurality of said emission modes; and (e) interpretation means for deriving information relating to each said emission mode represented by said multicomponent response signal from said multicomponent response signal. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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18. Apparatus as claimed in claim 17 wherein said interpretation means includes means for deriving lifetimes for said emission modes by solving a plurality of simultaneous equations selected from the group consisting of equations of the form:
- ##EQU13## and combinations thereof, wherein;
N represents an integer number of said emissions modes;
fi represents the contribution of response light arising from the ith said emission mode to the luminescence of frequency w as a fraction of the total amplitude of said response light at frequency w; and
space="preserve" listing-type="equation">τ
.sub.irepresents the lifetime of the ith emission mode.
- ##EQU13## and combinations thereof, wherein;
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19. Apparatus as claimed in claim 18 wherein said means for deriving lifetime for sad emission modes by solving a plurality of simultaneous equations includes means for solving said equations using known values for fi in each said equation.
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20. Apparatus as claimed in claim 19 wherein said means for deriving lifetimes for said emission modes by solving a plurality of simultaneous equations includes means for deriving values for N said lifetimes by solving at least N said equations for at least N said modulation frequencies.
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21. Apparatus as claimed in claim 18 wherein said means for deriving lifetimes for said emission modes by solving a plurality of simultaneous equations includes means for determining values for fi in said equations by solving said equations, said means for solving said equations being operative to derive values for N said lifetimes by solving at least 2N said equations for at leas N said modulation frequencies.
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Specification