Spectrometer
First Claim
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1. In a spectrographic analysis system in which a spectrum derived from a sample under test in projected onto a slit assembly, the assembly including slits positioned to pass only those spectral lines of interest in the measurement of the concentration of one of a number of different substances which may be present in the sample, the improvement comprising:
- said slit assembly comprising a liquid crystal cell with electrodes at opposite surfaces of the cell for defining the slits in response to voltages applied thereto; and
control means connected to said slit assembly for applying voltages to said electrodes for producing a selected one of a plurality of possible slit patterns, that one pattern being appropriate to the analysis of the particular substance of interest in the sample,said control means including modulating means for generating a slit modulating signal and for applying said slit modulation signal to a selected group of said slits to generate a modulated selected spectrum for opening the slits at the modulation frequency, and output means including detecting means for detecting said modulated spectrum, and means responsive to said detected modulated spectrum applied as an input thereto for generating said spectrum signal as an output thereof.
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Abstract
The slit assembly of the present spectrometer comprises a liquid crystal cell. The electrodes of the cell are selectively actuated for producing a pattern of slits appropriate to the spectral lines of interest in the spectrum derived from the substance under analysis.
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Citations
14 Claims
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1. In a spectrographic analysis system in which a spectrum derived from a sample under test in projected onto a slit assembly, the assembly including slits positioned to pass only those spectral lines of interest in the measurement of the concentration of one of a number of different substances which may be present in the sample, the improvement comprising:
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said slit assembly comprising a liquid crystal cell with electrodes at opposite surfaces of the cell for defining the slits in response to voltages applied thereto; and control means connected to said slit assembly for applying voltages to said electrodes for producing a selected one of a plurality of possible slit patterns, that one pattern being appropriate to the analysis of the particular substance of interest in the sample, said control means including modulating means for generating a slit modulating signal and for applying said slit modulation signal to a selected group of said slits to generate a modulated selected spectrum for opening the slits at the modulation frequency, and output means including detecting means for detecting said modulated spectrum, and means responsive to said detected modulated spectrum applied as an input thereto for generating said spectrum signal as an output thereof. - View Dependent Claims (2, 3, 4, 5)
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6. In a spectrographic analysis system for indicating the presence and concentration in a sample under test of any one of a number of different substances, and which includes means for translating radiation which has passed through the sample into a spectrum and means for directing that spectrum onto a slit assembly, an improved such assembly comprising:
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a liquid crystal cell comprising a liquid crystal and electrodes at opposite surfaces of said liquid crystal responsive to applied voltages for switching the liquid crystal between clear and opaque optical states, said electrodes defining a pattern of slits; and means for selectively applying voltages to said electrodes for producing a desired pattern of slits in positions corresponding to the spectral lines of interest in the spectrum being produced by the substance under analysis, said means for selectively applying including modulating means for generating a slit modulating signal and for applying said slit modulation signal to a selected group of said slits to generate a modulated selected spectrum for opening the slits at the modulation frequency, and output means including detecting means for detecting said modulated spectrum, and means responsive to said detected modulated spectrum applied as an input thereto for generating said spectrum signal as an output thereof. - View Dependent Claims (7)
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8. A spectrometer comprising:
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means for producing a spectrum of light, detector means for producing an output signal in response to said light spectrum incident thereon, an array of slits disposed between said detector means and said means for producing a spectrum of light, said array of slits being formed of liquid crystal material having first and second light transmission states, said slits transmitting the light incident thereon only when in one of said states, said liquid crystal material being selectively placed in said states in accordance with a plurality of slit control voltages applied thereto, electronic means connected to said liquid crystal material for generating said control voltages, said control voltates selectively placing a group of said slits in said one state, said electronic means including modulating means for generating a slit modulating signal and for applying said slit modulation signal to a selected group of said slits to generate a modulated selected spectrum for opening the slits at the modulation frequency, and output means including detecting means for detecting said modulated spectrum, and means responsive to said detected modulated spectrum applied as an input thereto for generating said spectrum signal as an output thereof, and output means responsive to said output signal applied as an input thereto for producing a spectrum signal representing the spectra transmitted by said selected group of slits. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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Specification