Digital fluorometer

Claim 3

The apparatus for measuring the characteristic parameter of the stimulated specimen radiation as claimed in claim 1 and further including energy control means for cyclically and alternately controlling said excitation source of energy and the reference source of energy to enable said detection signal to be alternately representative of the stimulated radiation emission from the specimen and the reference source of energy.

Claim 4

The apparatus for measuring the characteristic parameter of the stimulated specimen radiation as claimed in claim 2 wherein said pulse count signal producing means further includes means for producing a frequency signal whose frequency corresponds to the characteristic parameter reprEsented by the detection signal; and counting means responsive to the frequency signal and actuated by the energy control means for producing said pulse count signal.

Claim 5

The apparatus for measuring the characteristic parameter of the stimulated specimen radiation as claimed in claim 3 wherein said counting means includes an up-down counter responsive to the frequency signal and coupled to the energy control means to alternately increase and decrease the count in the counter in correspondence with the occurrence of alternating stimulated specimen radiation emission and reference source energy.

Claim 6

The apparatus for measuring the characteristic parameter of stimulated specimen radiation as claimed in claim 4 wherein said reference source varying means further includes a pulse generator; a rate multiplier having a pulse input responsive to the pulse generator and a multiplier input effectively responsive to the pulse count generated in the up-down counter to produce an output rate of pulses proportional to the pulse count; and means enabled by the energy control means for applying said output pulse rate from the rate multiplier to correspondingly energize the reference source of energy.

Claim 7

The apparatus for measuring the characteristic parameter of the stimulated specimen radiation as claimed in claim 4 wherein the reference source varying means further includes a latch network operatively coupled between the rate multiplier and the up-down counter to store its count after alternate energization of the excitation source of energy and reference source of energy.

Claim 8

The apparatus for measuring the characteristic parameter of the stimulated specimen radiation as claimed in claim 2 and further including means responsive to the pulse count signal for displaying an indication of the measured characteristic parameter.

Claim 9

A fluorometer for measuring the fluorescence stimulated from a specimen by an excitation source of radiation with the fluorescence from the specimen being detected by a photodetector comprising a reference light source directed at the photodetector; means for alternately exposing the photodetector to the fluorescence from the specimen and the light from the reference source; means for converting the output of the photodetector to a frequency signal whose frequency is representative of the magnitude of the photodetector output; means controlled by the alternate exposing means and responsive to the frequency signal for producing a pulse count signal representative of the amount of light from the reference source needed to balance the light from the fluorescing specimen; and means responsive to the pulse count signal for altering the amount of light from the reference source to establish said light balance.

Claim 10

A fluorometer for measuring the fluorescence stimulated from a specimen by an excitation source of radiation with the fluorescence from the specimen being detected by a photodetector comprising a reference light source directed at the photodetector; means for alternately exposing the photodetector to the fluorescence from the specimen and the light from the reference source; means for converting the output of the photodetector to a frequency signal whose frequency is representative of the magnitude of the photodetector output; means controlled by the alternate exposing means and responsive to the frequency signal for producing a pulse count signal representative of the amount of light from the reference source needed to balance the light from the fluorescing specimen; and means responsive to the pulse count signal for altering the amount of light from the reference source to establish said light balance.

Claim 11

The fluorometer as claimed in claim 8 wherein the alternately exposing means further includes means for generating light source enabling signals occurring at the same frequency and with separate phase; means responsive to the light source enabling signals to respectively energize the excitation source and the reference source.

Claim 12

The fluorometer as claimed in claim 9 wherein the means for altering the amount of light from the reference source further includes means for varying the average intensity level of the reference source during the light source enable signal applied thereto for energization.

Claim 13

The fluorometer as claimed in claim 10 wherein the average intensity varying means further includes means controlled by the pulse count for producing a train of pulses whose repetition rate during the time of the reference souce energization is selected to determine the average intensity level.

Claim 14

The fluorometer as claimed in claim 11 wherein said pulse train producing means includes a digital rate multiplier network having a pulse rate input, a multiplier input and a reduced multiplied pulse rate output, with the multiplier input effectively coupled to the pulse count signal.

Claim 15

The fluorometer as claimed in claim 12 wherein the light source enabling signal generating means further includes an oscillator and a counter responsive to the output from the oscillator to generate a reduced output frequency.

Claim 16

The fluorometer as claimed in claim 13 wherein the rate multiplier pulse rate input is selectively responsive to the oscillator or reduced output frequency thereof.

Claim 17

A fluorometer for measuring the fluorescence stimulated from a specimen by an excitation source of radiation with the fluorescence from the specimen being detected by a photodetector comprising an intensity variable reference light source directed at the photodetector, said excitation source and the reference light source being coupled to measure the amount of fluorescence from the specimen; means for alternately energizing the excitation light source and the reference light source during an operating cycle with the respective source energizations during each cycle selected to obtain an indication of the magnitude of the fluorescence from the specimen; means reponsive to the output of the photodetector for producing a digital control signal indicative of the difference in average light intensity between the fluorescence from the specimen and the light from the reference source during each cycle of energization; and means responsive to the digital control signal for varying the average intensity of the reference light source in a direction to establish a light balance between the fluorescence from the specimen and the reference light source.

Claim 18

A fluorometer for measuring the fluorescence stimulated from a specimen by an excitation source of radiation with the fluorescence from the specimen being detected by a photodetector comprising an intensity variable reference light source directed at the photodetector, said excitation source and the reference light source being coupled to measure the amount of fluorescence from the specimen; means for alternately energizing the excitation light source and the reference light source during an operating cycle with the respective source energizations during each cycle selected to obtain an indication of the magnitude of the fluorescence from the specimen; means reponsive to the output of the photodetector for producing a digital control signal indicative of the difference in average light intensity between the fluorescence from the specimen and the light from the reference source during each cycle of energization; and means responsive to the digital control signal for varying the average intensity of the reference light source in a direction to establish a light balance between the fluorescence from the specimen and the reference light source.

Claim 19

The fluorometer as claimed in claim 15 wherein the means for varying the average intensity of the reference light source further includes means responsive to the digital control signal for producing a train of energizing pulses at a repetition rate selected to establish the desired average light intensity from the reference light source, said train of energizing pulses being each effective to drive the reference light source for a pulse duration period to a preselected calibrated maximum level.

Claim 20

The fluorometer as claimed in claim 16 wherein the train of pulses producing means includes a rate multiplier network; means for generating a plurality of rate pulses selected to be modified in pulse repetition rate and applying the rate pulses to the rate multiplier; and means for applying the digital control signal to the rate multiplier network to determine the output pulse rate therefrom.

Claim 21

The fluorometer as claimed in claim 17 wherein the means for applying the digital control signal further includes a latch network for storing the digital control signal during each cycle and applying the latch-stored digital control signal to the rate multiplier network.

Claim 22

The fluorometer as claimed in claim 18 wherein the digital control signal producing means further includes means for smoothing the output of the photodetector; means for producing a frequency signal whose frequency is representative of the magnitude of the smoothed photodetector output; and an up-down counter reponsive to the frequency signal and controlled by the alternately energizing means to form said digital control signal.

Claim 23

The fluorometer as claimed in claim 21 and further including means responsive to the digital control signal to generate an indication of the intensity of the fluorescence when the photometric system is balanced.

Claim 24

A fluorometer for measuring the fluorescence stimulated from a specimen by an excitation source of light radiation with the fluorescence from the specimen being detected by a photodetector comprising an intensity variable reference light source directed at the photodetector, said excitation source and the reference light source being coupled to measure the amount of fluorescence from the specimen; a cycle generator coupled to alternately energize the excitation source and the reference light source; means for rapidly pulsing the reference light source between a low level and a high calibrated maximum level in correspondence with a pulse rate selected to establish a photometric balance over a cycle determined by the cycle generator; means responsive to the photodetector output for comparing during any one cycle the photodetector output attributable to the excitation source and the photodetector output attibutable to the reference light source and generating a digital control signal indicative thereof; and means for coupling the digital control signal to the rapidly pulsing means to control the rate thereof in accordance with the digital control signal and establish balance.

Claim 25

A fluorometer for measuring the fluorescence stimulated from a specimen by an excitation source of light radiation with the fluorescence from the specimen being detected by a photodetector comprising an intensity variable reference light source directed at the photodetector, said excitation source and the reference light source being coupled to measure the amount of fluorescence from the specimen; a cycle generator coupled to alternately energize the excitation source and the reference light source; means for rapidly pulsing the reference light source between a low level and a high calibrated maximum level in correspondence with a pulse rate selected to establish a photometric balance over a cycle determined by the cycle generator; means responsive to the photodetector output for comparing during any one cycle the photodetector output attributable to the excitation source and the photodetector output attibutable to the reference light source and generating a digital control signal indicative thereof; and means for coupling the digital control signal to the rapidly pulsing means to control the rate thereof in accordance with the digital control signal and establish balance.

Claim 26

The fluorometer as claimed in claim 21 wherein the cycle generator includes an oscillator and a binary divider responsive to the oscillator to provide a cycle signal determinative of the cycle rate for energizing of the excitation source and the reference light source, and a phase generator to provide phase-separated pulses for time separated energization of the excitation source and the reference light source.

Claim 27

The fluorometer as claimed in claim 22 wherein the respective duty cycles of the phase-separator pulses are substantially the same.

Claim 28

The fluorometer as claimed in claim 21 wherein the rapidly pulsing means further includes a rate multiplier network having a rate input, a multiplier input effectively coupled to the digital control signal and a reduced output pulse rate; and means for selectively coupling the cycle generator to the rate multiplier to establish a desired operating range for the balancing of the sample fluorescence with the rapidly pulsed reference light source.

Claim 29

The fluorometer as claimed in claim 24 wherein the comparing means further includes a latch network coupled to store the digital control signal.

Claim 30

The fluorometer as claimed in claim 25 wherein the reference light source is a light emitting semiconductor diode.