Radiant energy – Photocells; circuits and apparatus – Optical or pre-photocell system
Reexamination Certificate
2001-08-03
2003-12-16
Pyo, Kevin (Department: 2878)
Radiant energy
Photocells; circuits and apparatus
Optical or pre-photocell system
C250S216000
Reexamination Certificate
active
06664537
ABSTRACT:
CROSS REFERENCE TO RELATED APPLICATIONS
The invention claims priority of the German patent application 100 38 622.9 which is incorporated by reference herein.
FIELD OF THE INVENTION
The invention relates to a scanning microscope. In particular the invention relates to a confocal scanning microscope.
The invention furthermore relates to an optical arrangement. Lastly, the invention relates to a method for imaging in scanning microscopy.
BACKGROUND OF THE INVENTION
In scanning microscopy, a sample is illuminated with a light beam in order to observe the reflected or fluorescent light emitted by the sample. The focus of the light beam is generally moved in a sample plane by tilting two mirrors, the deflection axes usually being mutually perpendicular so that one mirror deflects in the x direction and the other deflects in the y direction. The tilting of the mirrors is performed, for example, with the aid of galvanometer control elements, in which case both fast, resonant as well as slower and more accurate nonresonant galvanometers are employed. The power of the light coming from the sample is measured as a function of the position of the scanning beam. In scanning microscopy and, in particular, in confocal scanning microscopy, lasers are preferably used as light sources in order to generate the illumination light beam for the sample.
In the scope of the scanning device, acousto-optical deflectors are also used instead of galvanometers, as disclosed for example by U.S. Pat. No. 4,893,008, “Scanning optical microscope”.
Especially in confocal scanning microscopy, a sample is frequently scanned in three dimensions by the focus of a light beam. A confocal scanning microscope generally comprises a light source, a focusing lens by which the light from the light source is focused onto a pinhole—the “excitation aperture”, a beam splitter, a scanning device for beam control, a microscope lens, a detection aperture and the detectors for registering the detection or fluorescent light. The illumination light, or the illumination light beam, is usually input via a main beam splitter. The fluorescent or reflected light coming from the sample travels via the same scanning device, or the same scanning mirror, back to the main beam splitter, and passes through the latter in order to be subsequently focused onto the detection aperture, behind which the detectors, usually photomultipliers, are located. Detection light which does not originate directly from the focus region takes a different light path and does not pass through the detection aperture, so that point information is obtained which leads to a three-dimensional image by sequential scanning of the sample. A three-dimensional image is usually achieved through layer-by-layer imaging.
In the galvanometer technology normally used at present, because of the inertia of the moving mechanical components, the maximum achievable scan rates are limited to a few hundred Hz for nonresonant galvanometers and a few kHz for resonant galvanometers. The end result of this is that the measurement times for each sample are relatively long.
Furthermore, the galvanometers generally have a length of several centimeters, the usually round mirrors having a diameter of about one centimeter. For beam deflection about two axes, at least two galvanometer mirrors in succession or cardanically interleaved are necessary. This galvanometer structure takes up a great deal of space in the microscope.
Although acousto-optical deflectors are faster than galvanometers, they nevertheless have the disadvantage that the beam quality is significantly deteriorated on passing through these elements. The circumstances responsible for this are described, for example, in “laser beam profile deformation effect during Bragg acousto-optic interaction: a non paraxial approximation”, Huang et al., Optical Engineering, July 1999, Vol. 38, No. 7, ISSN 0091-3286.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a scanning microscope with fast and reliable image-data acquisition and a compact structure.
According to the invention, the above object is achieved by a scanning microscope comprising: a light source for generating an illumination light beam, a scanning device for deflecting the illumination light beam across a sample, wherein the scanning device has at least one micromirror which is moveable in at least two directions, a cardan suspension or joint is provided to at least one micromirror and means for preferably simultaneous detection of the setting or position of at least one micromirror.
It is a further object of the invention to provide a confocal scanning microscope with fast and reliable image-data acquisition and a compact structure, produced with simply designed means.
The above object is achieved by a confocal scanning microscope, comprising a laser defining a light source for generating an illumination light beam, a scanning device for deflecting the illumination light beam across a sample, wherein the scanning device has at least one micromirror which is moveable in at least two directions, means for preferably simultaneous detection of the setting or position of at least one micromirror, and an adaptive lens for correcting micromirror defects or deformation of the micromirror surface.
It is a further object of the invention to provide an optical arrangement which provides fast and reliable image-data acquisition.
The above object is accomplished by an ptical arrangement comprising: a light source, for generating a illumination light beam, at least one micromirror for deflecting the illumination light beam, and an adaptive lens for correcting mirror defects or deformations of the mirror surface.
An additional object of the invention is to provides method for fast and reliable image-data acquisition.
The above object is accomplished by a method for imaging in scanning microscopy, comprising the steps of:
providing an illumination light beam with a laser,
using at least one micromirror for deflecting the illumination light beam and
deflecting the illumination light beam across a sample and thereby defining an actual scan path on the sample.
Through the use of a micromirror, the scanning rate can be significantly increased. A micromirror or a microelectrical scanner, as disclosed for example by PCT/US 99/00564 or by the journal OLE, November 1999, achieves very high deflection rates because of the low mass of the moving parts. The micromirrors are usually operated electrically at their resonant frequency. This is typically in the region of 20 kHz.
The micromirrors are often fabricated “from bulk” by lithographic methods, as are also employed in semiconductor technology, in such a way that only thin torsionable linking sections then carry the actual mirror.
A micromirror furthermore requires a significantly smaller assembly space. This greatly contributes to a compact scanning microscope structure.
Consequently, the scanning microscope according to the invention provides a scanning microscope in which fast and reliable image-data acquisition and a compact structure are produced with simply designed means.
With a view to reliable scanning of a specific sample area, at least one micromirror could be movable in at least two directions. At least one micromirror could then have a cardan suspension or joint. In the case of such a configuration of the micromirror, movable in at least two directions, no other mirror is needed for scanning the sample. This contributes to the compactness of the overall arrangement, a micromirror usually extending only over a few millimeters. Mirror areas of 3 mm×3 mm are typical.
To guarantee a high image quality, a scan point could be assignable to each detection signal. In this case, in particular, means could be provided for preferably simultaneous detection of the setting or position of at least one micromirror. This makes it simple to assign a detection signal to a scan point.
Specifically, the means could be designed for capacitive and/or inductive detection. This permits contactless detection.
As an al
Engelhardt Johann
Hoffmann Juergen
Foley & Lardner
Leica Microsystems Heidelberg GmbH
Pyo Kevin
Sohn Seung C.
LandOfFree
Scanning microscope, optical arrangement and method for... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Scanning microscope, optical arrangement and method for..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Scanning microscope, optical arrangement and method for... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3104964