Imaging spectrometer and camera with high spectral range

Patent metadata

Field	Value
Publication number	US-2025216260-A1
Application number	US-202318401346-A
Country	US
Kind code	A1
Filing date	Dec 30, 2023
Priority date	Dec 30, 2023
Publication date	Jul 3, 2025
Grant date	—

Abstract

An imaging spectrometer and camera are disclosed including a prism that refracts incident light a spectral range for spectrographic analysis with a shortest wavelength (λ S ) and a longest wavelength (λ L ). A diffraction grating is aligned with the prism and diffracts the incident light. The refraction and diffraction for a set of diffraction orders used for the spectrographic analysis both increase a deflection angle of the incident light from an original optical axis. The spectral range spans greater than an octave such that λ L >2λ S . The refraction and diffraction are such that a second diffracted order of λ S does not overlap with a first diffracted order of wavelengths shorter than λ L . The second order diffraction for wavelengths between λ S and λ C , and the first order diffraction for wavelengths between λ C and λ L , are detected in different spatial regions to perform the spectrographic analysis from λ S to λ L .

First claim

1 . An imaging spectrometer comprising:
a prism that refracts incident light in at least a spectral range for spectrographic analysis with a shortest wavelength (λ S ) and a longest wavelength (λ L ); a diffraction grating, positioned in optical alignment with the prism, that diffracts the incident light, wherein the refraction from the prism and the diffraction from the diffraction grating for a set of diffraction orders used for the spectrographic analysis both increase a deflection angle of the incident light from an original optical axis; and one or more sensors positioned to detect incident light that has passed through the prism and diffraction grating, wherein the spectral range spans greater than an octave such that λ L >2λ S , and wherein the combined refraction and diffraction of the prism and the diffraction grating are such that a second diffracted order of λ S does not spatially overlap with a first diffracted order of any wavelengths shorter than λ L at the one or more sensors, and there is sufficient diffraction into the second order for wavelengths between λ S and a selected wavelength (λ C ) in the spectral range such that the second order diffraction for wavelengths between λ S and λ C , and the first order diffraction for wavelengths between Ac and λ L , are detected with the one or more sensors in different spatial regions to perform the spectrographic analysis for the spectrum from λ S to λ L .

2 . The imaging spectrometer according to claim 1 wherein the diffraction grating is a blazed diffraction grating and has a grating blaze angle with a maximum diffraction efficiency in the first order at a wavelength (λ P ) such that 0.65<λ P /λ L <0.8.

3 . The imaging spectrometer according to claim 1 wherein the spectral range of the spectrometer is approximately 430-1000 nm.

4 . The imaging spectrometer according to claim 3 wherein λ C is approximately 525 nm.

5 . The imaging spectrometer according to claim 1 wherein the spectral range of the spectrometer is approximately 500-1100 nm.

6 . The imaging spectrometer according to claim 1 wherein the one or more sensors comprise a single focal plane array sensor which detects the second order diffraction for wavelengths between λ S and λ C , and the first order diffraction for wavelengths between λ C and λ L simultaneously along one spatial axis.

7 . The imaging spectrometer according to claim 6 wherein one spatial dimension of an image is captured along a sensor axis perpendicular to the axis capturing the spectral range.

8 . The imaging spectrometer according to claim 7 further comprising a scanning system operating on the incident light such that a second spatial dimension of the image is captured time sequentially as a series of frames.

9 . The imaging spectrometer according to claim 1 wherein both the first and second diffractive orders of the wavelengths near λ C are used in calculation of a resultant spectrum.

10 . The imaging spectrometer according to claim 1 further comprising a spectral filter which blocks wavelengths outside of the spectral range of the spectrometer from entering the spectrometer.

11 . An imaging spectrometer camera adapted to receive incident light from a medical scope, comprising:
an optical channel receiving and focusing incident light; and an imaging spectrometer positioned downstream from the optical channel and comprising:
a scanning system for adjusting a relative position of the imaging spectrometer with respect to the optical channel;
a prism that refracts incident light in at least a spectral range for spectrographic analysis with a shortest wavelength (λ S ) and a longest wavelength (λ L );
a diffraction grating, positioned in optical alignment with the prism, that diffracts the incident light, wherein the refraction from the prism and the diffraction from the diffraction grating for a set of diffraction orders used for the spectrographic analysis both increase a deflection angle of the incident light from an original optical axis; and
a focal plane array sensor positioned downstream from the prism and diffraction grating which detects the second order diffraction for wavelengths between λ S and a selected wavelength (λ C ) in the spectral range and the first order diffraction for wavelengths between λ C and λ L simultaneously along one spatial axis,
wherein the spectral range spans greater than an octave such that 2 L >2λ S , and wherein the combined refraction and diffraction of the prism and the diffraction grating are such that a second diffracted order of λ S does not spatially overlap with a first diffracted order of any wavelengths shorter than λ L at the focal plane array sensor.

12 . The imaging spectrometer camera according to claim 11 wherein the diffraction grating is a blazed diffraction grating that has a grating blaze angle with a maximum diffraction efficiency in the first order at a wavelength (λ P ) such that 0.65<λ P /λ L <0.8.

13 . The imaging spectrometer camera according to claim 11 wherein the spectral range of the spectrometer is approximately 430-1000 nm.

14 . The imaging spectrometer camera according to claim 13 wherein λ C is approximately 525 nm.

15 . The imaging spectrometer according to claim 11 wherein the spectral range of the spectrometer is approximately 500-1100 nm.

16 . The imaging spectrometer camera according to claim 11 wherein one spatial dimension of an image is captured along a sensor axis perpendicular to the axis capturing the spectral range.

17 . The imaging spectrometer camera according to claim 16 wherein the scanning system operates such that a second spatial dimension of the image is captured time sequentially as a series of frames.

18 . The imaging spectrometer according to claim 11 wherein both the first and second diffractive orders of the wavelengths near λ C are used in calculation of a resultant spectrum.

19 . The imaging spectrometer according to claim 11 further comprising a spectral filter which blocks wavelengths outside of the spectral range of the spectrometer from entering the spectrometer.

20 . The imaging spectrometer of claim 11 , wherein the diffraction grating is positioned downstream from the prism.

Assignees

• Storz Karl Imaging Inc

Inventors

• Duckett Iii George E

Classifications

• A61B5/0084

  for introduction into the body, e.g. by catheters (A61B5/1459 takes precedence) · CPC title

• A61B5/0075

  by spectroscopy, i.e. measuring spectra, e.g. Raman spectroscopy, infrared absorption spectroscopy (A61B5/0071 takes precedence) · CPC title

• G01J3/0205

  Optical elements not provided otherwise, e.g. optical manifolds, diffusers, windows · CPC title

• G01J3/36

  Investigating two or more bands of a spectrum by separate detectors · CPC title

• G01J3/1804

  Plane gratings · CPC title