Diffuse reflectance spectroscopy system and method
First Claim
1. A diffuse reflectance spectroscopy system comprising:
- a source of energy;
a sample at a sample plane;
means to direct the energy from the source of energy to a focus at a field stop plane;
a filter at the field stop plane operative to reflect the energy from the source of energy toward the sample in spatially separated energy bands; and
means to direct the energy bands onto the sample at the sample plane in focus to form an image of the filter at the sample plane and to return energy reflected from the sample to the filter;
the filter being operative to direct specularly reflected focused energy from the sample out of the system and to direct diffusely reflected unfocused energy from the sample to a detector.
1 Assignment
0 Petitions
Accused Products
Abstract
A spectroscopy system separates the diffuse reflectance component of a reflectance spectrum from the specular reflectance component using a remote field stop filter. The surface of the sample is placed at a focal plane of an optical system. The optical system forms an image on the surface of the sample that includes an image of the remote field stop filter. The optical system images the surface of the sample onto either the same or another remote field stop. Energy reflected from the surface of the sample which is in focus at the remote field stop retains the image information about the image of the filter, whereas energy reflected from below the surface of the sample does not necessarily retain image information about the image of the filter. Since the energy from the surface of the sample is specularly reflected and the energy from below the surface is diffusely reflected, the specular component of the reflectance spectrum is spatially separate from some of the diffuse reflection component at the remote image stop and is filtered out. The now filtered reflection spectrum contains diffusely reflected energy, which is directed to the detector of a spectrometer.
91 Citations
15 Claims
-
1. A diffuse reflectance spectroscopy system comprising:
-
a source of energy; a sample at a sample plane; means to direct the energy from the source of energy to a focus at a field stop plane; a filter at the field stop plane operative to reflect the energy from the source of energy toward the sample in spatially separated energy bands; and means to direct the energy bands onto the sample at the sample plane in focus to form an image of the filter at the sample plane and to return energy reflected from the sample to the filter; the filter being operative to direct specularly reflected focused energy from the sample out of the system and to direct diffusely reflected unfocused energy from the sample to a detector. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
-
-
9. A diffuse reflectance spectroscopy system comprising:
-
a source of energy; a sample at a sample plane; means to direct the energy from the source of energy to a focus at a first field stop plane; a first filter at the first field stop plane operative to direct energy from the source of energy toward the sample in spatially separated bands; means to direct the energy bands onto the sample plane in focus to form an image of the first filter at the sample plane and to return energy reflected from the sample to a second filter at a second field stop plane; the second filter being operative to direct specularly reflected focused energy from the sample out of the system and to direct diffusely reflected unfocused energy from the sample to a detector. - View Dependent Claims (10, 11)
-
-
12. A method of obtaining a diffuse reflectance spectrum in an optical system comprising the steps of:
-
introducing radiant energy into the system; focusing the radiant energy at a field stop; positioning a filter at this field stop; reflecting incident radiant energy from the source off of the filter to form discrete radiant energy bands; directing the radiant energy bands to a focus at a sample plane containing a sample, an image of the filter being formed at the sample plane; collecting the specularly and diffusely reflected radiant energy from the sample and returning the same to the filter; dividing specularly reflected sample energy from diffusely reflected sample energy at the filter; and directing only the diffusely reflected energy from the filter to a detector. - View Dependent Claims (13, 14)
-
-
15. A method of obtaining a diffuse reflectance spectrum in an optical system comprising the steps of:
-
introducing radiant energy into the system; focusing the radiant energy at a first field stop; positioning a first filter at the first field stop to form discrete energy bands; directing the discrete radiant energy bands to a focus at a sample plane containing a sample, forming an image of the first filter at the sample plane; collecting diffusely and specularly reflected radiant energy from the sample and returning the same to a second filter at a second field stop plane; dividing specularly reflected sample energy from the diffusely reflected sample energy at the second filter; and directing only the diffusely reflected energy from the second filter to a detector.
-
Specification