Patent Application
20080013086
To review the invention in further detail, it should be understood that the invention can be incorporated in any appropriate preexisting spectrometer arrangement. In particular, the astigmatic optical element 118 and the dual apertures 120 and 132 can be readily implemented in preexisting spectrometer arrangements which utilize Czerny-Turner spectrographs with spherical mirrors (e.g., the Oriel MS125 spectrograph provided by Newport Corporation, Stratford, Conn.). Since the configuration of the spectrometer may vary, it should be understood that the components and arrangement of the sample mount 102, light source 104, the optical elements such as the collection lens 106, mirror 108, objective lens 110, etc., and the monochromator 114 and detector 116 may vary widely (and some of these elements may be omitted, may be replaced by functionally similar elements, and/or may be comprised of several individual elements). Additional components may be present as well, with an obvious example being a housing which includes mountings for the components illustrated in the drawings (with no such housing or mountings being shown in the drawings). Additional optical elements are also readily accommodated, e.g., beam-folding mirrors which alter the path of the image so that the overall arrangement of the spectrometer 100 may be made more compact, or may otherwise better fit some desired configuration.
The astigmatic optical element 118 may be any optical element which provides different focal lengths in different planes, and can be a lens (such as the toroidal lens 118 of
The drawings (particularly FIGS. 1A and 1C-1D) illustrate varying the size of the first aperture 132 in a discrete fashion by replacing the first aperture 132 with substitute first apertures 132A, 132B, and 132C having different aperture sizes. In contrast,
In practice, the spectrometer 100 may be used with both apertures 132 and 120 installed (and narrowed) to present an effective pinhole aperture for confocal imaging of the sample 102. Alternatively, if a larger area of the sample 102 is to be analyzed, one of the apertures 132 and 120 may be adapted so that it does not interfere with the image beam (i.e., it may be enlarged about the beam or moved from the beam path). As a result, the detector 116 will receive (and generate measurements from) a slit image rather than a pinhole image. If desired, the other aperture may also be adapted as well, as by slightly narrowing or enlarging it, to vary the resolution of the measurements.
In the foregoing arrangement, it is preferred that the second aperture 120 remain as the entrance to the spectrograph 112, and that the first aperture 132 be insertable/removable and/or respaceable outside the spectrograph 112 to avoid interference with the image beam. In this manner, the spectrograph 112 and/or its monochromator 114 may be constructed, installed, and removed for maintenance as a unit, with the second aperture 120 being held in a fixed location with respect to the diffraction grating 124 (as well as with respect to the collimating reflector 122, second reflector 126, and detector 116). This is beneficial since maintaining the second aperture 120 in a substantially fixed location with respect to the spectrograph 112 (in particular the diffraction grating 124) substantially reduces or eliminates many of the misalignment difficulties that arise in prior arrangements wherein the entrance aperture of the spectrograph was repositionable with respect to the remaining spectrograph components.
The invention is not intended to be limited to the preferred versions described above, but rather is intended to be limited only by the claims set out below. Thus, the invention encompasses all different versions that fall literally or equivalently within the scope of these claims.
