Radiant energy – Invisible radiant energy responsive electric signalling – Infrared responsive
Reexamination Certificate
2001-08-03
2004-02-17
Hannaher, Constantine (Department: 2878)
Radiant energy
Invisible radiant energy responsive electric signalling
Infrared responsive
Reexamination Certificate
active
06693280
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to the field of mid-infrared (mid-IR) spectrometry, and more specifically to an attachment to infinity-corrected, commercially available light microscopes to provide the techniques of internal and external reflection infrared microspectrometry.
BACKGROUND OF THE INVENTION
Spectroscopic analysis using radiant energy in the infrared region of the electromagnetic radiation spectrum is a primary technique for chemical analysis of molecular compounds. The infrared spectral region extends from 0.7 to 250-micrometers, however the mid-IR region is generally considered to cover the region from about 2.5 to about 25-micrometers (or parts thereof), which is commonly used for molecular vibrational spectroscopy. While the primary distinction between near-IR and mid-IR regions is based upon whether the underlying molecular frequencies are fundamental or overtone frequencies, instrument components tend to differ and also be specific by region. There is some overlap however, and specifically mid-IR Fourier transform infrared spectrometers typically cover that part of the near-IR region from 1 to 2.5 micrometers.
This invention defines an attachment apparatus and method for infrared spectroscopic or radiometric analysis of microscopic samples of solids or liquids, including biological materials, combining external or internal reflection spectroscopy with visible light and near-IR radiant energy viewing of microscopic samples by using an attachment to standard commercially available visible light microscopes and commercially available video cameras. The magnification optics for infrared spectral analysis are infrared transmitting objective lenses that are used to focus a beam of radiant energy onto a sample, or sample surface, collect the reflected radiant energy, and present that energy to a detector system for spectral analysis.
Since the introduction of commercial infrared microspectrometers, the advantage of combining the capabilities of a visible-light microscope with an infrared spectrometer has been of great importance. Infrared microscopes, such as those disclosed in U.S. Pat. No. 4,878,747 (the '747 patent) issued to Donald W. Sting and Robert G. Messerschmidt, have been used for an ever-expanding range of applications. These specialized microscopes were attached to commercial Fourier transform infrared (FT-IR) spectrometers. Such microscope/FT-IR systems have been used to detect and identify trace contaminants, to analyze multilayered composites, micro-electronic devices, phase distributions in polymeric materials, inclusions in minerals, abnormal cellular materials, DNA, and numerous other materials.
Heretofore, all known combinations of mid-IR spectrometers and visible light microscopes were composed of (1) a combination of a general purpose laboratory spectrometer and an attachment to the spectrometer having visible light illumination and viewing, or (2) a specially designed integrated instrument combining infrared spectroscopy and visible imaging features. In all cases, the resulting products emphasized the infrared spectroscopy capability, utilizing visible microscopy capabilities as a means to support the infrared spectroscopy capability.
Known special infrared microscope systems and attachments to mid-IR spectrometers have become pervasive even though such systems and attachments are costly and complex. The microscope attachments to laboratory FT-IR spectrometers, described in the '747 patent to Sting and Messerschmidt, among others, have become the standard configurations for infrared microspectroscopy systems. These complex microscope attachments typically provide both transmission and reflection capabilities and use variable remote-image-plane masks to define sample areas for infrared analysis. All of this known art, however, consists of special purpose FT-IR microscopes with specialized optical systems that are appended to large bench-top spectrometers, or fully integrated FT-IR microscope systems using some visible light microscope components. No such systems known use an attachment to visible light microscopes, as is contemplated by our invention.
Our invention provides for the use of both external-reflection and internal-reflection microspectroscopy techniques. Internal-reflection microspectroscopy provides certain advantages over both transmission and external reflection microspectroscopy, particularly in the ability to analyze thick samples. With the introduction of internal-reflection microspectrometry, as shown in U.S. Pat. No. 5,093,580 to Donald W. Sting, and U.S. Pat. No. 5,200,609 to Donald W. Sting and John A. Reffner (also known as attenuated total reflection microspectrometry or micro-ATR) reflection microspectrometry has gained ever-greater importance. Furthermore, our invention extends the capabilities of internal-reflection microspectroscopy by using the unique ATR technology disclosed in U.S. Pat. Nos. 5,703,366 and 5,552,604 issued to Sting and Milosevic to create a novel infinity-corrected ATR objective used for microspectroscopy.
All previous forms of infrared microspectroscopy apparatus were designed from the perspective of the spectroscopist, whereas this invention is designed from the perspective of those using visible light microscopes. Our invention treats the infrared spectroscopy capability as an adjunct to a visible light microscope, and thereby provides extension of the visible microscope's capabilities. It is a primary object of the present invention to provide an FT-IR spectrometer attachment that is easily attached to a commercially available light microscope without compromising any of the available visible light microscope features, options, and capabilities.
SUMMARY OF THE INVENTION
The present invention provides an optical system, apparatus and method to use a mid-IR spectrometer system as an attachment to commercial light microscopes for molecular analysis of materials. In this invention a small spectrometer, in combination with optical, mechanical and electronic components, form an apparatus that can be directly attached to a light microscope for measurement of infrared spectra of microscopic samples or sample domains. Because it can be readily attached directly to existing microscopes, using conventional mechanical connectors that are typically used for microscopes, costs are significantly lower than the current art method of using a dedicated infrared microscope that is attached to a laboratory FT-IR spectrometer. Furthermore, because of the ease of use and accessibility of such low cost infrared spectroscopy capability to material scientists, biologists, and pathologists, as well as others using conventional visible light microscopes, it is expected that significant interdisciplinary benefits will occur.
Using our invention, infrared spectra are acquired using either the external-reflection or the internal-reflection spectroscopy technique. By using reflection spectroscopy techniques, nearly all types of samples can be analyzed. A thin film of material for example, can be mounted on an infrared reflective, but visibly transmissive, substrate such as low-E glass to be analyzed by reflection-absorption, a special case of external-reflection, whereby infrared radiation from the spectrometer is directed onto and through the sample film to the low-E glass substrate, where the radiation is reflected and subsequently passes through the film a second time, whereupon the radiation ultimately is directed to a detector for analysis. An absorption spectrum is thereby acquired, but the measurement was made using the external-reflection technique. For external-reflection spectroscopy, the external-reflection infrared objective lens does not contact the sample, as it must with the ATR objective lens which is used for internal-reflection spectroscopy.
Any thick or thin sample that is placed in contact with the internal-reflection element of an ATR objective lens can result in an ATR spectrum. Because the infrared spectrum of most samples can be measured by using either i
Burch Robert V.
Reffner John A.
Sting Donald W.
Wilks Donald K.
Calfee Halter & Griswold LLP
Hannaher Constantine
Lee Shun K.
Sensir Technologies, L.L.C.
LandOfFree
Mid-infrared spectrometer attachment to light microscopes does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Mid-infrared spectrometer attachment to light microscopes, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Mid-infrared spectrometer attachment to light microscopes will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3329810