Optical alignment system for optical spectrometers

Claim 2

A spectroscopic apparatus comprising: a. first means for exciting a chemical sample to emit characteristic radiation; b. second means for directing said characteristic radiation along a first optical path; c. third means for diffracting said characteristic radiation from said first optical path into a spectrum; d. fourth means for reading said spectrum; e. a pair of solid state light sources mounted on a circuit board, said solid state light sources spatially separated with respect to each other, said solid state light sources having alternatively bright regions when subjected to an alternating voltage for emitting monitor radiation, said solid state light sources energized sequentially on alternate half cycles of said alternating voltage; f. an entrance slit in registration with said pair of light sources for directing said monitor radiation from each said source along a second optical path toward said third means, said monitor radiation diffracted at angles falling outside the spectral range normally utilized by the spectRoscopic apparatus; g. an offset exit slit for said monitor radiation diffracted by said third means; h. photo detector means in registration with said exit slit for receiving said monitor radiation from said exit slit in order to produce signals of a character that depends upon the orientation of said third means with respect to said entrance and exit slits; i. filter means interposed between said exit slit and photo detector means for optically separating said diffracted characteristic radiation from said monitor radiation; and j. fifth means responsive to said signals produced by said photo detector means for controlling the relative orientations of said third means with respect to said entrance and exit slits.

Claim 3

The spectroscopic apparatus as claimed in claim 1 wherein each said solid state light source is a light-emitting diode.

Claim 4

The spectroscopic apparatus as claimed in claim 1 wherein said filter means is a sharp cut on red glass filter.

Claim 5

The spectroscopic apparatus as claimed in claim 1 wherein said third means is a diffraction grating and wherein said light sources with said entrance slit and said exit slit with said photo detector means are positioned symmetrically about the normal of said diffraction grating.

Claim 6

The spectroscopic apparatus as claimed in claim 1 wherein said fifth means includes; a. servo amplifier means electrically connected to said photo detector means for generating a drive signal which depends upon the orientation of said third means with respect to said entrance and exit slits; b. power supply means operatively connected to said light sources and servo amplifier means, said power supply means having balance means for controlling the relative intensity of the monitor radiation emitted from said light sources; and c. servo motor means electrically connected to said servo amplifier means and operatively connected to said third means, said servo motor being responsive to said drive signals for controlling the relative orientations of said third means with respect to said entrance and exit slits.

Claim 7

The spectroscopic apparatus as claimed in claim 5 wherein said servo amplifier means includes: a. first threshold means defining an upper level for said signal produced by said photo detector means; and b. second threshold means defining a lower level for said signals produced by said photo detector means.

Claim 8

A spectrometer for indicating the chemical composition of a specimen by determining the intensity distribution, at selected wavelengths, of radiation emitted by the specimen under excitation, said spectrometer comprising: a. first means for exciting the specimen to emit characteristic radiation; b. second means for directing said characteristic radiation along a first optical path; c. grating means for diffracting said characteristic radiation from said first optical path into a spectrum; d. third means for reading said spectrum; e. a pair of solid state light sources mounted on a circuit board, said solid state light sources spatially separated with respect to each other, said solid state light sources having alternatively bright regions when subjected to an alternating voltage for emitting monitor radiation, said monitor radiation having a wavelength out of the range of wavelengths normally analyzed by the spectrometer apparatus; f. an entrance slit in registration with said pair of light sources for directing said monitor radiation from each said source along a second optical path toward said grating means, said monitor radiation diffracted at angles falling outside the spectral range normally utilized by the spectrometer; g. an offset exit slit for said monitor radiation diffracted by said grating means, said monitor radiation diffracted at an angle falling outside the spectral range of said characteristic radiation; h. photo detector means in registration with said exit slit for receiving said monitor radiation from said exit sliT in order to produce signals of a character that depends upon the orientation of said grating means with respect to said entrance and exit slits, said light sources with said entrance slit and said exit slit with said photo detector means are positioned symmetrically about the normal of said grating means; and i. fourth means responsive to said signals produced by said photo detector means for controlling the relative orientations of said grating means with respect to said entrance and exit slit means.

Claim 9

A spectrometer for indicating the chemical composition of a specimen by determining the intensity distribution, at selected wavelengths, of radiation emitted by the specimen under excitation, said spectrometer comprising: a. first means for exciting the specimen to emit characteristic radiation; b. second means for directing said characteristic radiation along a first optical path; c. grating means for diffracting said characteristic radiation from said first optical path into a spectrum; d. third means for reading said spectrum; e. a pair of solid state light sources mounted on a circuit board, said solid state light sources spatially separated with respect to each other, said solid state light sources having alternatively bright regions when subjected to an alternating voltage for emitting monitor radiation, said monitor radiation having a wavelength out of the range of wavelengths normally analyzed by the spectrometer apparatus; f. an entrance slit in registration with said pair of light sources for directing said monitor radiation from each said source along a second optical path toward said grating means, said monitor radiation diffracted at angles falling outside the spectral range normally utilized by the spectrometer; g. an offset exit slit for said monitor radiation diffracted by said grating means, said monitor radiation diffracted at an angle falling outside the spectral range of said characteristic radiation; h. photo detector means in registration with said exit slit for receiving said monitor radiation from said exit sliT in order to produce signals of a character that depends upon the orientation of said grating means with respect to said entrance and exit slits, said light sources with said entrance slit and said exit slit with said photo detector means are positioned symmetrically about the normal of said grating means; and i. fourth means responsive to said signals produced by said photo detector means for controlling the relative orientations of said grating means with respect to said entrance and exit slit means.

Claim 10

The spectrometer as claimed in claim 7 wherein each said light source is a light-emitting diode.

Claim 11

The spectrometer as claimed in claim 8 wherein each said light-emitting diode is composed of PN gallium arsenide phosphide.

Claim 12

In combination with a diffraction grating, a system for automatically and predeterminedly orienting said diffraction grating with respect to entrance and exit slits, radiation from a specimen under excitation directed through the entrance slit and diffracted by said diffraction grating through said exit slits, said system comprising: a. a pair of solid state light sources mounted on circuit board means, said solid state light sources spatially separated with respect to each other, each said source characterized by regions which emit monitor radiation; b. an entrance slit in registration with said pair of light sources for directing said monitor radiation from said sources toward the diffraction grating, said monitor radiation diffracted at an angle falling outside the spectral range of the specimen radiation; c. an offset exit slit for said monitor radiation transmitted through said entrance slit from said sources and diffracted by the grating; d. photo detector means in registration with said offset exit slit for receiving said radiation from said offset exit slit in order to produce signals of a character that depends upon the orientation of said diffraction grating with respect to the entrance and exit slits; and e. means responsive to said signals produced by said photo detector means for controlling the relative orientations of the grating with respect to said entrance and exit slits.

Claim 13

In combination with a diffraction grating, a system for automatically and predeterminedly orienting said diffraction grating with respect to entrance and exit slits, radiation from a specimen under excitation directed through the entrance slit and diffracted by said diffraction grating through said exit slits, said system comprising: a. a pair of solid state light sources mounted on circuit board means, said solid state light sources spatially separated with respect to each other, each said source characterized by regions which emit monitor radiation; b. an entrance slit in registration with said pair of light sources for directing said monitor radiation from said sources toward the diffraction grating, said monitor radiation diffracted at an angle falling outside the spectral range of the specimen radiation; c. an offset exit slit for said monitor radiation transmitted through said entrance slit from said sources and diffracted by the grating; d. photo detector means in registration with said offset exit slit for receiving said radiation from said offset exit slit in order to produce signals of a character that depends upon the orientation of said diffraction grating with respect to the entrance and exit slits; and e. means responsive to said signals produced by said photo detector means for controlling the relative orientations of the grating with respect to said entrance and exit slits.

Claim 14

The system as claimed in claim 9 wherein said second entrance slit and said offset exit slit are positioned symmetrically about the normal of the grating.

Claim 15

The system as claimed in claim 10 including filter means interposed between said offset exit slit and photo detector means for optically separating said specimen radiation and monitor radiation.