Spectrometer with rotary scanning disc and method of spectroscopic analysis

Claim 2

A spectrometer for providing spectral information concerning a scene comprising: an opaque rotary scanning disc having at least two circumferEntially spaced radial scanning slits equally spaced from the rotation axis of the disc; beam forming means for collecting and forming into a beam radiation from said scene; dispersion means for dispersing the radiation of said beam into a spectrum; imaging means for forming a focused image of said spectrum on said disc over the circular path of rotation of said slits with said disc in a manner such that the spectral lines of said image extend generally radially of the disc whereby said slits undergo lateral scanning movement in succession across said image during rotation of said disc; radiation sensing means behind said disc for receiving and generating an electrical signal representing the radiation incident on each scanning slit during its scanning movement along said image; one of said slits being totally transparent to said radiation, whereby said one slit transmits to said sensing means all of the radiation incident on the latter slit during its scanning movement along said image; and narrow band pass filter means across the other slit which transmits radiation only within at least one narrow band of said spectrum.

Claim 3

A spectrometer according to claim 1 wherein: said filter means comprises a pair of narrow bandpass filters each occupying approximately one-half of the respective slit; and said filters having transmission frequency bands near the ends, respectively, of said radiation spectrum.

Claim 4

A spectrometer according to claim 1 wherein: said scanning disc contains a number of said scanning slits arranged in a circular row centered on said rotation axis and narrow band pass filter means across alternate slits which transmit radiation only within at least said one narrow band of said spectrum; and at least some of the remaining intervening slits being totally transparent to said radiation.

Claim 5

A spectrometer according to claim 3 wherein: each said filter means comprises a pair of narrow band pass filters, each occupying approximately one-half of the respective slit; and said filters having transmission frequency bands near the ends, respectively of said radiation spectrum.

Claim 6

A spectrometer according to claim 3 including: means for mounting over one of said transparent slits a filter having selected radiation transmission characteristics.

Claim 7

A spectrometer according to claim 3 wherein: all of said slits except one are of substantially equal size and said one slit is enlarged.

Claim 8

A spectrometer according to claim 6, wherein: said enlarged slit is a transparent slit.

Claim 9

A spectrometer according to claim 1 wherein: said scanning disc contains a number of said scanning slits arranged in a circular row centered on said rotation axis and narrow band pass filter means across alternate slits which transmit radiation only within at least said one narrow band of said spectrum; at least some of the remaining intervening slits being totally transparent to said radiation; each said filter means comprises a pair of narrow bandpass filters each occupying approximately one-half of the respective slit; said filters having transmission frequency bands near the ends, respectively, of said radiation spectrum; means for mounting over one of said transparent slits a filter having selected radiation transmission characteristics; and all of said slits except one of said transparent slits are of substantially equal size and said one transparent slit is enlarged.

Claim 10

A spectrometer for providing spectral information concerning a scene, comprising: beam forming means for collecting and collimating into a beam radiation from said scene, said beam forming means including a radiation opaque mask having a radiation transparent entrance slit, and objective lens in front of said slit for producing an image of said scene in the plane of said slit, a concave spherical mirror behind said slit for receiving radiation from said image and reflecting the incident Radiation in the form of a collimated radiation beam; a diffraction grating positioned in front of said mirror on the axis of said beam for dispersing the radiation of said beam into a spectrum and reflecting said spectrum back to said mirror; said mirror reflecting said spectrum toward an image plane and forming in said plane a focused image of said spectrum; a rotary radiation opaque scanning disc positioned in said plane and containing a number of radial radiation transparent slits arranged in a circular row concentric with the rotation axis of said disc; said slits being uniformly spaced along said row and said spectrum image being formed over and in tangential relation to said row, whereby rotation of said disc is effective to cause lateral scanning movement of said slits in rapid succession along said spectrum image; means for driving said disc in rotation; radiation sensing means positioned behind said disc opposite said spectrum image for receiving radiation from said image through each slit during its scanning movement along said image; narrow band pass filter means across alternate slits which transmit radiation only within at least one narrow band of said spectrum; at least some of the remaining intervening slits being totally transparent to said radiation; and all of said slits except one are of substantially equal size and said one slit is enlarged.

Claim 11

A spectrometer for providing spectral information concerning a scene, comprising: beam forming means for collecting and collimating into a beam radiation from said scene, said beam forming means including a radiation opaque mask having a radiation transparent entrance slit, and objective lens in front of said slit for producing an image of said scene in the plane of said slit, a concave spherical mirror behind said slit for receiving radiation from said image and reflecting the incident Radiation in the form of a collimated radiation beam; a diffraction grating positioned in front of said mirror on the axis of said beam for dispersing the radiation of said beam into a spectrum and reflecting said spectrum back to said mirror; said mirror reflecting said spectrum toward an image plane and forming in said plane a focused image of said spectrum; a rotary radiation opaque scanning disc positioned in said plane and containing a number of radial radiation transparent slits arranged in a circular row concentric with the rotation axis of said disc; said slits being uniformly spaced along said row and said spectrum image being formed over and in tangential relation to said row, whereby rotation of said disc is effective to cause lateral scanning movement of said slits in rapid succession along said spectrum image; means for driving said disc in rotation; radiation sensing means positioned behind said disc opposite said spectrum image for receiving radiation from said image through each slit during its scanning movement along said image; narrow band pass filter means across alternate slits which transmit radiation only within at least one narrow band of said spectrum; at least some of the remaining intervening slits being totally transparent to said radiation; and all of said slits except one are of substantially equal size and said one slit is enlarged.

Claim 12

A spectrometer according to claim 9 including: means on said disc for mounting a selected radiation filter over one transparent slit.

Claim 13

A spectrometer according to claim 9 wherein: each filter means comprises a pair of narrow bandpass filters each occupying approximately one-half its respective slit; and said filters having transmission frequency bands near the ends of said radiation spectrum.