U.S. patent application number 12/485023 was filed with the patent office on 2009-10-08 for method and apparatus for conducting raman spectroscopy.
This patent application is currently assigned to AHURA SCIENTIFIC INC.. Invention is credited to Masud Azimi, Kevin J. Knopp, Daryoosh Vakhshoori, Peidong Wang.
Application Number | 20090251694 12/485023 |
Document ID | / |
Family ID | 46325666 |
Filed Date | 2009-10-08 |
United States Patent
Application |
20090251694 |
Kind Code |
A1 |
Knopp; Kevin J. ; et
al. |
October 8, 2009 |
Method and Apparatus for Conducting Raman Spectroscopy
Abstract
A Raman probe system includes: a base station; a mobile robot
remotely controllable from the base station; a Raman probe assembly
supported by the robot, the Raman probe assembly including a laser
and a spectrometer; a camera supported by the robot; and a
communication subsystem operable to communicate images from the
camera and results from the Raman probe assembly to the base
station. In some embodiments, a Raman probe system includes: a
mobile robot remotely controllable from a base station, the robot
including a body and an articulated arm; a camera supported by the
robot; a Raman probe assembly supported by the robot, the optical
control assembly mounted on the body of the robot; and an optical
probe mounted on the articulated arm of the robot; and a wireless
communication system operable to communicate images from the camera
and results from the Raman probe assembly to the base station.
Inventors: |
Knopp; Kevin J.;
(Newburyport, MA) ; Wang; Peidong; (Carlisle,
MA) ; Azimi; Masud; (Belmont, MA) ;
Vakhshoori; Daryoosh; (Cambridge, MA) |
Correspondence
Address: |
FISH & RICHARDSON PC
P.O. BOX 1022
MINNEAPOLIS
MN
55440-1022
US
|
Assignee: |
AHURA SCIENTIFIC INC.
Wilimington
MA
|
Family ID: |
46325666 |
Appl. No.: |
12/485023 |
Filed: |
June 15, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11475582 |
Jun 27, 2006 |
7548311 |
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12485023 |
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11117940 |
Apr 29, 2005 |
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11475582 |
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60694385 |
Jun 27, 2005 |
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60607735 |
Sep 7, 2004 |
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60566713 |
Apr 30, 2004 |
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Current U.S.
Class: |
356/301 ;
901/1 |
Current CPC
Class: |
G01J 3/0208 20130101;
G01J 3/0232 20130101; G01J 3/0272 20130101; G01J 3/0227 20130101;
G01J 3/0291 20130101; G01J 3/02 20130101; G01J 3/44 20130101; G01J
3/0218 20130101; G01J 2003/1213 20130101; G01N 21/65 20130101; G01N
2021/656 20130101 |
Class at
Publication: |
356/301 ;
901/1 |
International
Class: |
G01J 3/44 20060101
G01J003/44 |
Claims
1-13. (canceled)
14. A Raman probe system comprising: a base station; a mobile robot
remotely controllable from the base station; a Raman probe assembly
supported by the robot, the Raman probe assembly including a laser
and a spectrometer; a camera supported by the robot; and a
communication subsystem operable to communicate images from the
camera and results from the Raman probe assembly to the base
station.
15. The Raman probe system of claim 14, wherein the communication
subsystem comprises a radio.
16. The Raman probe system of claim 14, wherein the communication
subsystem comprises a radio.
17. The Raman probe system of claim 14, wherein the Raman probe
assembly also includes an optical probe, the optical probe mounted
to an articulating arm of the robot.
18. The Raman probe system of claim 14, wherein the Raman probe
assembly also includes an analysis apparatus which receives
wavelength characteristics of a Raman signature from the
spectrometer.
19. The Raman probe system of claim 18, wherein the communication
subsystem is operable to communicate results from the analysis
apparatus to the base station.
20. The Raman probe system of claim 19, wherein the communication
subsystem is operable to send the Raman signature to the base
station.
21. The Raman probe system of claim 14, wherein the communication
subsystem comprises a transmitter configured to transmit
information using an Internet Web protocol.
22. The Raman probe system of claim 21, wherein the Internet Web
protocol is IEEE 802.11b wireless network standards.
23. The Raman probe system of claim 14, wherein the Raman probe
assembly comprises a standoff cone.
24. The Raman probe system of claim 23, when the standoff cone is
constructed such that a distal tip is positioned at a focal point
of the laser.
25. A Raman probe system comprising: a mobile robot remotely
controllable from a base station, the robot including a body and an
articulated arm; a camera supported by the robot; a Raman probe
assembly supported by the robot, the Raman probe assembly
comprising: an optical control assembly including a laser and a
spectrometer, the optical control assembly mounted on the body of
the robot; and an optical probe mounted on the articulated arm of
the robot; and a wireless communication system operable to
communicate images from the camera and results from the Raman probe
assembly to the base station.
26. The Raman probe system of claim 25, wherein the Raman probe
assembly also includes an analysis apparatus which receives
wavelength characteristics of a Raman signature from the
spectrometer.
27. The Raman probe system of claim 26, wherein the communication
system is operable to communicate results from the analysis
apparatus to the base station.
28. The Raman probe system of claim 27, wherein the communication
system is operable to send the Raman signature to the base
station.
29. The Raman probe system of claim 25, wherein the communication
subsystem comprises a transmitter configured to transmit
information using an Internet Web protocol.
30. The Raman probe system of claim 29, wherein the Internet Web
protocol is IEEE 802.11b wireless network standards.
31. The Raman probe system of claim 25, wherein the Raman probe
assembly comprises a standoff cone.
32. The Raman probe system of claim 31, when the standoff cone is
constructed such that a distal tip is positioned at a focal point
of the laser.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This patent application a continuation application of and
claims priority to U.S. application Ser. No. 11/475,582, filed on
Jun. 27, 2006.
[0002] Patent application Ser. No. 11/475,582:
[0003] (i) is a continuation-in-part of pending prior U.S. patent
application Ser. No. 11/117,940, filed Apr. 29, 2005 by Peidong
Wang et al. for METHOD AND APPARATUS FOR CONDUCTING RAMAN
SPECTROSCOPY (Attorney's Docket No. AHURA-2230); and
[0004] (ii) claims benefit of pending prior U.S. Provisional Patent
Application Ser. No. 60/694,385, filed Jun. 27, 2005 by Kevin J.
Knopp et al. for RAMAN IDENTIFICATION SYSTEM (Attorney's Docket No.
AHURA-35 PROV);
[0005] both of which are hereby incorporated herein by
reference.
TECHNICAL FIELD
[0006] This disclosure relates to methods and apparatus for
identifying and characterizing substances in general, and more
particularly to methods and apparatus for identifying and
characterizing substances using Raman spectroscopy.
BACKGROUND
[0007] Raman spectroscopy is a viable technique for identifying and
characterizing a vast array of substances. Raman spectroscopy is
widely used in the scientific, commercial and public safety
areas.
[0008] Recent technological advances are making it possible to
increase the range of applications using Raman spectroscopy through
a reduction in cost and size. For example, portable units have
recently become available for field uses such as the on-site
identification of potentially hazardous substances.
[0009] Unfortunately, with Raman spectroscopy, it is generally
desirable to bring the optical probe to a position adjacent to the
specimen when conducting the Raman spectroscopy. However, this can
be a problem in view of the potentially hazardous materials which
are to be analyzed, e.g., explosives, chemical agents, toxic
industrial chemicals, etc.
[0010] Accordingly, a primary object of the present disclosure is
to provide an improved Raman spectroscopy system which overcomes
the aforementioned shortcomings of currently available systems.
SUMMARY
[0011] In one preferred embodiment, there is provided an improved
Raman probe system in which a remote Raman probe assembly is
mounted to a remote control robot for unmanned delivery to a remote
specimen. The remote Raman probe assembly includes a wireless
communication feature for transmitting information from the remote
Raman probe assembly to a base unit. If desired, the wireless
communication feature can take the form of a wireless Web link, so
as to simplify communication transmission. Furthermore, the remote
Raman probe assembly may comprise a Raman probe which may be
attached to a robot arm, with the remainder of the remote Raman
probe assembly being mounted to the body of the robot, such that
the Raman probe can be selectively positioned vis-a-vis the
specimen.
[0012] In another form, there is provided a Raman probe assembly
for analyzing a specimen, comprising: a light source for generating
laser excitation light; a camera for capturing an image; a light
analyzer for analyzing a Raman signature; and a light path for (i)
delivering the laser excitation light from the light source to the
specimen so as to produce the Raman signature for the specimen,
(ii) capturing an image of the specimen and directing that image to
the camera, and (iii) directing the Raman signature of the specimen
to the light analyzer.
[0013] In another form, there is provided a Raman probe assembly
for analyzing a specimen, comprising: a light source for generating
laser excitation light; a camera for capturing an image; a light
analyzer for analyzing a Raman signature; a first light path for
delivering the laser excitation light from the light source to the
specimen so as to produce the Raman signature for the specimen; a
second light path for capturing an image of the specimen and
directing that image to the camera; a third light path for
directing the Raman signature of the specimen to the light
analyzer; wherein the a least a portion of the first light path,
the second light path and the third light path are coaxial with one
another.
[0014] In another form, there is provided a Raman probe assembly
for analyzing a specimen, comprising: a light source for generating
laser excitation light; a light analyzer for analyzing a Raman
signature; a light path for (i) delivering the laser excitation
light from the light source to the specimen so as to produce the
Raman signature for the specimen, and (ii) directing the Raman
signature of the specimen to the light analyzer; wherein the
assembly further comprises a probe body for housing the at least a
portion of the light path, and a window, with the light path
extending through the window; and further wherein the probe body
further comprises a shutter/wiper disposed adjacent to the
window.
[0015] In another form, there is provided a Raman probe assembly
for analyzing a specimen, comprising: a light source for generating
laser excitation light; a light analyzer for analyzing a Raman
signature; a light path for (i) delivering the laser excitation
light from the light source to the specimen so as to produce the
Raman signature for the specimen, and (ii) directing the Raman
signature of the specimen to the light analyzer; and wherein the
light analyzer comprises a transmitter for transmitting information
using an Internet Web protocol.
[0016] In another form, there is provided a method for identifying
the nature of a specimen, the method comprising: providing a Raman
probe assembly comprising: a light source for generating laser
excitation light; a camera for capturing an image; a light analyzer
for analyzing a Raman signature; a light path for (i) delivering
the laser excitation light from the light source to the specimen so
as to produce the Raman signature for the specimen, (ii) capturing
an image of the specimen and directing that image to the camera,
and (iii) directing the Raman signature of the specimen to the
light analyzer wherein the assembly further comprises a probe body
for housing the at least a portion of the light path, and a window,
with the light path extending through the window; wherein the probe
body further comprises a shutter/wiper disposed adjacent to the
window; wherein the assembly is carried by a remote controlled
robot; providing a base station for receiving the image, and for
remotely controlling the robot, and for receiving information from
the light analyzer; navigating the remote control robot from the
base station to a position adjacent to the specimen; opening the
shutter/wiper; using the camera to aim the probe body at the
specimen; energizing the light source so that the laser excitation
light is directed at the specimen; and analyzing the return light
passed to the light analyzer so as to determine of the nature of
the specimen.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] These and other objects and features of the present
disclosure will be more fully disclosed or rendered obvious by the
following detailed description of the preferred embodiments, which
is to be considered together with the accompanying drawings wherein
like numbers refer to like parts and further wherein:
[0018] FIG. 1 is a schematic view of a novel Raman probe
system;
[0019] FIG. 2 is a schematic view of selected elements of the Raman
probe system;
[0020] FIG. 3 is a schematic view of the Raman probe system's laser
subsystem, optical probe subsystem and spectrometer subsystem;
[0021] FIGS. 4-7 are schematic views of the optical control
unit;
[0022] FIGS. 8-11 are schematic view of the Raman probe;
[0023] FIG. 12 is a schematic view showing the specimen being
targeted through the probe;
[0024] FIG. 13 is a schematic view of the system controller;
and
[0025] FIGS. 14 and 15 are schematic views showing a standoff cone
used in conjunction with the optical probe assembly.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0026] Looking first at FIG. 1, there is shown a novel Raman probe
system 5 for conducting remote sensing of a specimen 10. Novel
Raman probe system 5 generally comprises a remote control robot 15
for piloting a remote Raman probe assembly 20 to a position
adjacent to specimen 10, and a base station 25 for controlling
operation of remote control robot 15 and for receiving specimen
analysis information from remote Raman probe assembly 20.
[0027] Remote control robot 15 may be any remote control robot of
the sort well known in the art of remote transport, remote sensing,
remote bomb disposal, etc. By way of example but not limitation,
remote control robot 15 may be a tracked vehicle remotely
controlled by base station 25, e.g., by radio control of the sort
well known in the art.
[0028] Looking now at FIGS. 1-3, remote Raman probe assembly 20
generally comprises a laser subsystem 30 (FIGS. 2 and 3) for
generating the Raman pump signal, an optical probe subsystem 35
(FIG. 3) for delivering the Raman pump signal to the specimen and
for gathering the Raman signature from the specimen, and a
spectrometer subsystem 40 (FIGS. 2 and 3) for analyzing the Raman
signature of the specimen so as to determine the nature of the
specimen, and for transmitting analysis data to base station
25.
[0029] For convenience, laser subsystem 30 and spectrometer
subsystem 40 may be packaged into an optical control unit 45 (see
FIGS. 4-7) which is mounted onto remote control robot 15 so as to
be carried thereby. Optical control unit 45 may also house an
onboard power supply (e.g., a battery) for powering remote control
robot 15 and its payload. Furthermore, optical control unit 45 is
preferably provided with a communication subsystem 47 for
permitting remote control robot 15, and its payload, to communicate
with base station 25.
[0030] Optical probe subsystem 35 is also mounted to remote control
robot 15. Preferably optical probe subsystem 35 is mounted to an
articulating arm 50 (FIG. 1) on remote control robot 15.
Articulating arm 50 may be remotely controlled by base station 25,
such that the working end of optical probe subsystem 35 may be
appropriately positioned adjacent to the specimen 10, as will
hereinafter be discussed.
[0031] Laser subsystem 30 may comprise any laser suitable for use
in Raman spectroscopy. By way of example but not limitation, laser
subsystem 30 may comprise one or more >300 mW, 785 nm
semiconductor lasers with limited linewidths (e.g., .about.2
cm.sup.-1). The output of laser subsystem 30 is delivered into the
excitation fiber (see below) of optical probe subsystem 35 for
delivery to the specimen.
[0032] Optical probe subsystem 35 is shown in FIGS. 3 and 8-11.
Optical probe subsystem 35 comprises an excitation fiber 53 (e.g.,
100 micrometer core diameter, Low OH) which delivers the excitation
light through a flat polished excitation fiber ferule 54 (e.g., a
100 micrometer Core multimode fiber) and then through a laser
collimating lens 54A (e.g., PCX, f=3 mm, D=3 mm) to a reflector 55
(e.g., for a 785 nm laser) and then to a notch filter 60 (e.g.,
OD>6) which also aligns the excitation light with the
longitudinal axis of the Raman probe 65. The excitation light is
then focused using focusing lens 70 (e.g., PCX, f32 6 mm, D=3 mm)
and then passed through a first pair of telescopic lenses 75, 80
(e.g., Achromat, f=19 mm, D=12.7 mm), a second pair of telescopic
lenses 85, 90 (e.g., Achromat, f=45 mm, D=25 mm), and a window 95
for permitting the excitation light to pass out of the distal end
of Raman probe 65 and onto specimen 10.
[0033] A shutter/wiper assembly 100 is disposed adjacent to window
95. Shutter/wiper assembly 100 is adapted to (i) selectively close
off window 95 so as to protect the window (e.g., during storage and
selected transit); and/or (ii) wiper off window 95 so as to keep it
free of debris (e.g., during scanning in a dusty and/or
debris-laden environment). Furthermore, shutter/wiper assembly 90
can be used to wiper away any of specimen 10 which might
unintentionally stick to window 95, so as to help ensure that the
specimen is not inadvertently carried away from the remote site by
Raman probe system 5 at the conclusion of the analysis.
[0034] The excitation light from optical probe subsystem 35 engages
specimen 10 and interacts with specimen 10 so as to produce the
Raman signature of the specimen.
[0035] The light returning from specimen 10 (including but not
limited to the Raman signature of the specimen) passes back through
window 95, through lenses 90, 85 and then through lens 80. A beam
splitter 105 (e.g., gold coated glass, 1.5.times.3.8 mm, 1 mm
thick) then directs some of the returning light through an imaging
lens 105A, through a CCD imaging lens aperture 106 (e.g., D=0.9
mm), through an infra red blocking filter 107 (e.g., to block 785
nm laser light and pass visible spectrum, OD>3) to CCD chip 108
on CCD active die 109 of CCD camera 110 driven by CCD electronics
115; and the remainder of the returning light (including the Raman
signature of the specimen) is directed through lens 75, through
focusing lens 70, through notch filters 60, 116 (e.g., OD>6),
through a collection collimator lens 118 (e.g., PCX, f=4 mm, D=6
mm), through a flat polished collection fiber ferrule 119 (e.g., a
200 micrometer Core multimode fiber) and into collection fiber 120
(e.g., 200 micrometer core diameter, Low OH) for delivery to
spectrometer subsystem 40. A shield 11 9A may be provided around
CCD camera 110 for stray and laser light blocking.
[0036] Preferably, CCD camera 110 and CCD electronics 115 are
constructed so as to provide streaming digital video output to base
station 25. Preferably, CCD electronics 115 are contained in Raman
probe 65 or, alternatively, some or all of CCD electronics 115 may
be contained within optical control unit 45. In any case, CCD
electronics 115 are carried by remote control robot 15.
[0037] The output from CCD camera 110 is relayed to base station
25, whereby to permit a user at base station 25 to aim the Raman
pump light on specimen 10. More particularly, and looking now at
FIG. 12, CCD camera 110 and base station 25 can be configured to
overlay cross-hairs 125 on the image provided by CCD camera 110,
whereby to permit the user to maneuver articulating arm 50 so that
the Raman pump light is directed onto specimen 10.
[0038] Spectrometer subsystem 40 generally comprises a spectrometer
130 for identifying the wavelength characteristics of the Raman
signature of specimen 10. Spectrometer subsystem 40 sends the
wavelength characteristics of the Raman signature of specimen 10 to
analysis apparatus 135, which determines the nature of specimen 10
using the wavelength characteristics of the Raman signature. If
desired, spectrometer 130 may comprise a dispersive spectrometer
having a resolution of 7-10.5 cm.sup.-1, a spectral range of
250-2800 cm.sup.-1, and 2048 pixels.
[0039] Thus it will be appreciated that specimen analysis is
conducted completely onboard remote control robot 15, and only the
analysis results need be communicated to base station 25. However,
in one preferred form, it is preferred that remote control robot 15
be configured to send base station 25 the Raman signature spectra,
as well as the analysis results.
[0040] Base station 25 preferably comprises a system controller
140, preferably including a computer having appropriate user
interface controls (e.g., a joystick, touch pad, etc.) for (i)
controlling the operation of remote control robot 15, including its
articulating arm 50; (ii) receiving the output from CCD camera 110,
whereby to permit remote aiming of Raman probe 65; and (iii)
receiving the analysis results from analysis apparatus 135.
[0041] If desired, Raman probe assembly 20 and base station 25 may
also be provided with a Raman feedback loop, whereby to use the
relative intensity of the Raman signature being obtained by the
system so as to further improve alignment of Raman probe 65 with
specimen 10. More particularly, base station 25 is configured so as
to measure (either continuously or on a periodic basis) how much
useful Raman signal is being collected by the system. Then, using a
feedback loop, the intensity of the Raman signal can be used, in
conjunction with cross-hairs 125, to help guarantee that Raman
probe 65 is properly aimed at specimen 10.
[0042] In one preferred form, some or all of the communication
links between (i) remote controlled robot 15 and/or its payload
(i.e., Raman probe assembly 20, including CCD camera 110 and CCD
electronics 115) and (ii) base station 25, may be effected via
Internet Web-based protocols, e.g., the IEEE 802.11b wireless
network standard.
[0043] If desired, remote control robot 15 can communicate analysis
results, Raman spectra or any other information (e.g., CCD camera
pictures) to a location other than, or in addition to, base station
25.
Use
[0044] Raman probe system 5 is preferably used as follows.
[0045] First, the user interface controls at base station 25 are
used to navigate remote control robot 15, including its
articulating arm 50, to position Raman probe 65 adjacent to
specimen 10, e.g., within approximately 1 to 2 inches.
[0046] Then, shutter/wiper 100 is opened, and CCD camera 110 and
CCD electronics 115 are used, in conjunction with the cross-hairs
125, to move articulating arm 50 so that Raman probe 65 is aimed at
specimen 10 and positioned approximately 30 mm away from the
specimen.
[0047] Then the Raman signature feedback system is used to optimize
positioning of Raman probe 65 relative to specimen 10. This is done
by energizing laser subsystem 30 so that Raman pump light is
directed at specimen 10 and reading the intensity of the Raman
signature returned from specimen 10, with a feedback loop driving
the positioning of articulating arm 50, so as to optimize the
position of Raman probe 65 relative to the specimen, whereby to
provide the best possible Raman signature for the specimen.
[0048] Then, laser subsystem 30 is energized so that the Raman pump
light is directed at specimen 10. The return light is passed to
spectrometer 130, so as to determine the Raman signature of the
specimen, and then the Raman signature is fed to analysis apparatus
135 for determination of the nature of the specimen. Analysis
apparatus 135 then sends information regarding the nature of
specimen 10 (optionally including the Raman spectra for specimen 10
as well) to base station 25.
Further Constructions
[0049] If desired, various modifications can be made to the
foregoing construction without departing from the scope of the
present invention.
[0050] Thus, for example, and looking now at FIGS. 14 and 15, the
shutter/wiper 100 may be replaced by a standoff cone 145. The
standoff cone 145 can have various lengths, depending on whether
specimen 10 is a solid or a liquid. More particularly, for solid
specimens, standoff cone 145 is constructed so that when the distal
tip of the standoff cone is positioned against the specimen, the
focal point of the Raman laser will be located on the surface of
the specimen. However, for liquid specimens, standoff cone 145 is
constructed so that when the distal tip of the standoff cone is
positioned against the specimen, the focal point of the Raman laser
will be located on the within the body of the specimen.
[0051] It is to be understood that the present invention is by no
means limited to the particular constructions herein disclosed
and/or shown in the drawings, but also comprises any modifications
or equivalents within the scope of the invention.
* * * * *