Light emitting diode spectrophotometer
First Claim
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1. A spectrophotometer with a high signal to noise ratio, comprising:
- a first light emitting diode for emitting light through a solution having a spectrophotometric absorbance maximum within the band of wavelengths of light emitted by said light emitting diode;
a first pulse generator connected to said light emitting diode, said pulse generator providing pulses having a duty cycle and voltage selected so that said light emitting diode emits light of higher intensity during pulses generated by said pulse generator than that maximum intensity that said light emitting diode could produce with a continuous voltage without damage to said light emitting diode;
a photodetector optically coupled to said light emitting diode for detecting light emitted from said light emitting diode and passed through said solution; and
a first signal generator coupled to said photodetector for generating a signal representative of the intensity of the light detected by said photodetector.
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Abstract
A spectrophotometer incorporating a pulsed light emitting diode as a source of radiation. The light emitting diode emits substantially monochromatic light thus negating the need for a separate wavelength control. The spectrophotometer may incorporate a pair of light emitting diodes for performing bichromatic spectrophotometric determinations. The light emitting diodes are pulsed with a duty cycle and pulse amplitude such that it is possible to obtain a higher amplitude pulse than the light emitting diode could sustain at a continuous voltage input level. Continuous voltages at this level would damage the light emitting diode.
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Citations
25 Claims
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1. A spectrophotometer with a high signal to noise ratio, comprising:
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a first light emitting diode for emitting light through a solution having a spectrophotometric absorbance maximum within the band of wavelengths of light emitted by said light emitting diode; a first pulse generator connected to said light emitting diode, said pulse generator providing pulses having a duty cycle and voltage selected so that said light emitting diode emits light of higher intensity during pulses generated by said pulse generator than that maximum intensity that said light emitting diode could produce with a continuous voltage without damage to said light emitting diode; a photodetector optically coupled to said light emitting diode for detecting light emitted from said light emitting diode and passed through said solution; and a first signal generator coupled to said photodetector for generating a signal representative of the intensity of the light detected by said photodetector. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A high signal to noise spectrophotometer comprising:
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a laser diode for emitting radiation through a solution having a spectrophotometric absorbance maximum within the band of wavelengths emitted by said laser diode; a pluse generator connected to said laser diode said pulse generator providing pulses having a duty cycle and voltage selected, so that said laser diode emits higher intensity radiation during pulses generated by said pulse generator then that maximum intensity that said laser diode could produce with a continuous voltage without damage to said laser diode; a photodetector, positioned so it that detects the main portion of the direct beam of radiation emitted by said laser diode, the main portion being partially absorbed when passed through said solution; and a first signal generator coupled to said photodetector for generating a signal representative of the intensity of the radiation detected by said detector.
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17. A method of optically measuring properties of a solution comprising the steps of:
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(a) pulsing a light emitting diode with pulses having a duty cycle and voltage selected so that said light emitting diode emits light of higher intensity during pulses generated by said pulse generator than that maximum intensity that the light emitting diode could produce with a continuous voltage; (b) passing light from the light emitting diode through a first solution; (c) detecting the light after it passes through said first solution; (d) generating a first signal representative of the intensity of the light detected in said detecting step; and (e) generating from said first signal an indication relating to the intensity of the light detected. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25)
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Specification