Light measuring apparatus
First Claim
1. Apparatus of the type for measuring light emitted, scattered, or reflected from a specimen, the apparatus comprisinga. a source of excitation radiation arranged to illuminate the specimen,b. modulating means for modulating the excitation radiation,c. means for emitting a K signal when the specimen has been subjected to a selected amount of excitation radiation,d. a photodetector arranged to provide an electrical signal in response to the intensity of the light emitted, scattered, or reflected by the specimen,d. means for amplifying the output signal of the photodetector,f. a phase sensitive detector having the amplified signal applied to its input,g. means coupled to the modulating means and deriving signals therefrom which regulate the operation of the phase sensitive detector,h. an integrator having its input coupled to the output of the phase sensitive detector, andi. means responsive to the K signal for measuring the quantum of the signal accumulated in the integrator at the emission of the K signal.
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Accused Products
Abstract
Apparatus usable as a fluorometer for measuring the concentration of fluorescent material in a specimen employs a flashing lamp to illuminate the specimen with excitation radiation. The intensity of the fluorescence emitted by the specimen is therefore modulated at the flash rate. That modulated fluorescence is converted by a photodetector to an electrical signal. The electrical signal is amplified and is passed through a phase sensitive detector to an integrator. The phase sensitive detector is regulated to operate at a rate related to the flash rate whereby an appropriately rectified signal is fed to the integrator. When the specimen has been subjected to a selected amount of excitation radiation, a signal is generated which marks the end of the integration interval. The accumulated signal in the integrator is then measured to obtain a measurement of the quantity of fluorescent material in the specimen. The apparatus is also usable as a nephelometer to measure the light scattering properties of a specimen illuminated by the flashing lamp.
44 Citations
6 Claims
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1. Apparatus of the type for measuring light emitted, scattered, or reflected from a specimen, the apparatus comprising
a. a source of excitation radiation arranged to illuminate the specimen, b. modulating means for modulating the excitation radiation, c. means for emitting a K signal when the specimen has been subjected to a selected amount of excitation radiation, d. a photodetector arranged to provide an electrical signal in response to the intensity of the light emitted, scattered, or reflected by the specimen, d. means for amplifying the output signal of the photodetector, f. a phase sensitive detector having the amplified signal applied to its input, g. means coupled to the modulating means and deriving signals therefrom which regulate the operation of the phase sensitive detector, h. an integrator having its input coupled to the output of the phase sensitive detector, and i. means responsive to the K signal for measuring the quantum of the signal accumulated in the integrator at the emission of the K signal.
Specification