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US 5,475,221 AGranted
Optical spectrometer using light emitting diode array
AssigneeBrimrose Corporation of America
InventorXiaolu Wang
Life of this patent
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Abstract
A novel optical device is provided which uses an array of light emitting diodes, controlled by novel multiplexing schemes, to replace conventional broad band light sources in devices such as spectrometers.
Claims6
A spectrometer comprising:
- a broad band light source, said source comprising an array of light emitting diodes, the individual diodes of which each emit a narrow wavelength band but the combination of which emit a desired range of wavelengths;
- switch means for controlling whether an individual diode is on or off at any given time;
- and multiplexing means for controlling said switch means so as to produce a desired total wavelength range;
- and
- a monochromator comprising an acousto-optic tunable filter means optically coupled and responsive to said broad band light source.
2 more elements
A spectrometer comprising:
- a broad band light source, said source comprising an array of light emitting diodes, the individual diodes of which each emit a narrow wavelength band but the combination of which emit a desired range of wavelength;
- the optical intensity of the LED array being amplitude modulated by a reference signal through electrical bias current;
- a monochromator comprising an acousto-optic tunable filter optically coupled and responsive to said broad band light source;
- a reference signal, and
- a lock-in amplifier for selectively amplifying a detected signal only if said signal is in proper phase and frequency compared to the reference signal.
2 more elements
Dependencies are inferred from the claim text.