U.S. patent application number 11/783902 was filed with the patent office on 2007-11-01 for correction device for an optical arrangement and confocal microscope with such a device.
This patent application is currently assigned to CARL ZEISS JENA GMBH. Invention is credited to Saskia Pergande, Joerg Steinert, Matthias Wald.
Application Number | 20070253044 11/783902 |
Document ID | / |
Family ID | 34854181 |
Filed Date | 2007-11-01 |
United States Patent
Application |
20070253044 |
Kind Code |
A1 |
Steinert; Joerg ; et
al. |
November 1, 2007 |
Correction device for an optical arrangement and confocal
microscope with such a device
Abstract
A correction device for an imaging optical arrangement
exhibiting a light path (1), in particular for a microscope, that
exhibits at least one plane-parallel transparent plate (9), which
is held in a mounting plate in the image beam path (1) and is
propelable around at least one axle in a tipping and/or a swiveling
motion, in order in adjust a definite parallel misalignment of the
beams in the image beam path (1) by a change in the tipping
situation of the plate (9). A confocal microscope with such a
correction device exhibits a confocal screen (4), which illustrates
a specimen mark (10), whereby the plane-parallel plate (9) is
placed in front of the detector unit (2) in the light path (1), in
order to center the illustration of the aperture diaphragm on the
detector unit.
Inventors: |
Steinert; Joerg; (Jena,
DE) ; Wald; Matthias; (Kunitz, DE) ; Pergande;
Saskia; (Jena, DE) |
Correspondence
Address: |
JACOBSON HOLMAN PLLC
400 SEVENTH STREET N.W.
SUITE 600
WASHINGTON
DC
20004
US
|
Assignee: |
CARL ZEISS JENA GMBH
Jena
DE
|
Family ID: |
34854181 |
Appl. No.: |
11/783902 |
Filed: |
April 12, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10967347 |
Oct 19, 2004 |
|
|
|
11783902 |
Apr 12, 2007 |
|
|
|
Current U.S.
Class: |
359/810 |
Current CPC
Class: |
G02B 27/0068 20130101;
G02B 21/0072 20130101; G02B 21/0052 20130101; G02B 7/004 20130101;
G02B 26/0875 20130101 |
Class at
Publication: |
359/196 |
International
Class: |
G02B 26/08 20060101
G02B026/08 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 16, 2004 |
DE |
10 2004 034 960.6 |
Claims
1. (canceled)
2. (canceled)
3. Microscope according to claim 15, further comprising changeable
or adjustable elements in the light path, and a servo unit (C),
which records at least one operating parameter of the microscope
and which adjusts the tilting situation to be dependent of the
value of the operating parameter, wherein the servo unit (C)
records a configuration of the changeable or adjustable elements as
operating parameters.
4. Confocal microscope according to claim 15, further comprising an
automatic control loop (C) that uses the tilting situation of the
at least two plane-parallel transparent plates as a correcting
variable, wherein the automatic control loop (C) maximizes the
radiation intensity at the detector unit or minimizes an image
misalignment, or both.
5. Microscope according to claim 15, comprising two plane-parallel
transparent plates, wherein the plane-parallel transparent plates
are independently movable and are made from materials of different
dispersion, in order to adjust one of a color-independent and aimed
color-dependent parallel misalignment.
6. Microscope according to claim 14, wherein the at least one
plane-parallel transparent plate comprises two sub panels and is
made with materials of different dispersion, in order to compensate
color transverse errors in the light path.
7. (canceled)
8. Microscope according to claim 14, wherein the detector unit
covers a locally resolved detector.
9. Microscope according to claim 14, further comprising changeable
or adjustable elements in the light path, and a servo unit (C),
which records at least one operating parameter of the confocal
microscope and which adjusts the tilting situation to be dependent
of the value of the operating parameter, wherein the servo unit (C)
records a configuration of the changeable or adjustable elements as
operating parameters.
10. Microscope according to claim 9, wherein the light path guides
radiation of different wavelengths and the servo unit (C) records
the wavelength in the light path as an operating parameter.
11. Microscope according to claim 14, further comprising an
automatic control loop (C) that uses the tilting situation of the
at least one plane-parallel transparent plate as a correcting
variable, wherein the automatic control loop (C) maximizes the
radiation intensity at the detector unit or minimizes an image
misalignment, or both.
12. Microscope according to claim 14, further comprising a servo
unit (C), which records at least one operating parameter of the
optical arrangement and which adjusts the tilting situation to be
dependent of the value of the operating parameter, and wherein the
confocal slit is designed as a slit diaphragm and the detector unit
is designed as a line detector and wherein the tilting situation is
adjustable about two axes such that the image of a specimen line is
centered on the slit diaphragm.
13. Microscope according to claim 14, further comprising a servo
unit (C), which records at least one operating parameter of the
optical arrangement and which adjusts the tilting situation to be
dependent of the value of the operating parameter, and wherein the
confocal slit is designed as a slit diaphragm and the detector unit
is designed as a line detector and wherein the tilting situation is
adjustable about two axes such that the image of the slit diaphragm
is centered about two axes on the detector line.
14. Confocal microscope having a beam path and comprising: a
confocal slit, a detector unit following the confocal slit, and a
correction device for focusing a selected specimen field on the
confocal slit, wherein the correction device includes: (a) at least
one plane-parallel transparent plate, wherein the at least one
plane-parallel transparent plate has at least one of a tilting and
swiveling movement around at least two axes, wherein the
plane-parallel transparent plate is provided between the specimen
field and the confocal slit and also between the confocal slit and
the detector unit, and (b) at least one mounting plate in the image
beam path, wherein the mounting plate holds the plane-parallel
transparent plate in the image beam path and moves the
plane-parallel transparent plate in at least one of a tilting
movement and a swiveling around at least two axes, in order to
adjust a constant parallel misalignment (dx, dy) of the beams in
the light path by change of the tilting situation of the
plane-parallel transparent plate, wherein the plane-parallel
transparent plate is placed first in the light path of the detector
unit, in order to center the image of the selected specimen field
on one of the detector unit and an image of the confocal slit on
the detector unit.
15. Confocal microscope having a beam path and comprising: a
confocal slit, a detector unit following the confocal slit, and a
correction device for focusing a selected specimen field on the
confocal slit, wherein the correction device includes: at least two
plane-parallel transparent plates, each of the plane-parallel
transparent plates being tiltable around one axis wherein one of
the plane-parallel transparent plates is provided between the
specimen field and the confocal slit and another of the
plane-parallel transparent plates is provided between the slit and
the detector unit, and (b) at least two mounting plates in the
image beam path, wherein each of the mounting plates holds one of
the plane-parallel transparent plates in the image beam path and
moves the plane-parallel transparent plate in one of a tilting
movement and a swiveling around one axis, in order to adjust a
constant parallel misalignment (dx, dy) of the beams in the light
path by change of the tilting situation of the plane-parallel
transparent plate, wherein the at least two plane-parallel
transparent plates are placed first in the light path of the
detector unit, in order to center the image of the selected
specimen field on one of the detector unit and an image of the
confocal slit on the detector unit.
16. Microscope according to claim 14 wherein the microscope has an
excitation light path for the illumination of the selected specimen
field, and wherein the at least one plane-parallel plate is
included in the excitation light path.
17. Microscope according to claim 15, wherein each of the at least
two plane-parallel transparent plates comprises two sub panels and
is made with materials of different dispersion, in order to
compensate color transverse errors in the light path.
18. Microscope according to claim 3, wherein the light path guides
radiation of different wavelengths and the servo unit (C) records
the wavelength in the light path as an operating parameter.
19. Microscope according to claim 15, wherein the detector unit
covers a locally resolved detector.
20. Microscope according to claim 15 wherein the microscope has an
excitation light path for the illumination of the selected specimen
field, and wherein the at least two plane-parallel plates are
included in the excitation light path.
Description
[0001] This application is a continuation application of U.S. Ser.
No. 10/967,347 filed Oct. 19, 2004 which is incorporated in its
entirety by reference herein.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The invention refers to a correction device for an optical
arrangement that exhibits a light path, for example for a
microscope. It specially refers to a confocal microscope with such
a correction device.
[0004] 2. Related Art
[0005] Optical arrangements, like for example microscopes, confocal
microscopes or laser scanning microscopes regularly exhibit
adjustable elements, in order to adjust different operating
conditions. Thus it is well known for example, to exchange filters
or color splitters, in order to be able to work with different
lighting wavelengths or to evaluate different fluorescence
radiation in different wavelength ranges. The adjustment or change
mechanisms must be implemented regularly, mechanically and very
expensively and with high precision, in order to keep the chances
of unwanted disturbances of the light path during element change or
element adjustment as small as possible.
[0006] This problem is faced especially in confocal microscopes or
laser scanning microscopes, in which a confocal slit with a
detector unit is used, that either contains a detector screen on
its side or acts as one. Since even with very large mechanical
expenditure for the changeable or adjustable elements, influences
of the light path for example by tipping errors or wedge errors at
the optical element can never be completely ruled out, partially
cost-effective correction mechanisms are provided in the prior art,
to change the light path of the image with such
pinhole-objectives.
[0007] Thus in DE 101 47 481 A1 for example an adjustable confocal
slit for a laser scanning microscope is described, that makes a
displacement of the aperture possible, to be able to shift the
confocal slit appropriately in tipping errors or wedge errors that
are caused by adjustment or change of optical elements, so that an
optimal image is always formed in the confocal microscope. The DE
101 07 210 C1 describes a similar approach, which likewise adjusts
relevant elements in the optical arrangement. There, in a confocal
microscope a focusing lens in the arrangement can be shifted
transverse to the Z-axis of the light path. It can also be used to
bring about an adjustment of the image in the confocal
microscope.
[0008] It is thus common in the approaches of the prior art, to
change the optical arrangements in the confocal microscope, i.e. in
the optical imaging arrangement--either by the change of the
location of a confocal slit with respect to the object to be imaged
or by the adjustment of other imaging elements of the imaging
optics. Apart from a relatively large mechanical/optical effort
necessary in these approaches, there exists a fundamental problem
in this principle pursued in the state of the art, that the
reproduction ratios are no longer comparable from time to time. A
laborious new calibration of imaging scales can become
necessary.
SUMMARY OF THE INVENTION
[0009] Therefore the purpose of this invention is to provide a
correction device for an optical imaging arrangement, with which a
correction can be applied without adjusting the optical image
itself, especially without having to adjust the optical
elements.
[0010] According to the invention this task is solved with a
correction device for an imaging optical arrangement exhibiting an
optical path, wherein the device exhibits at least one plane
parallel transparent plate, that is held in a mounting plate in the
optical path and is movable around at least one axle by means of
the mounting plate in a tipping movement and/or swiveling, in order
to adjust a constant parallel misalignment of the light path by
change of the tipping situation of the plate.
[0011] The invention especially provides for a confocal microscope,
whereby the microscope focuses a selected specimen area on a
confocal slit, to which a detector unit is subordinate and whereby
the plate is placed first in the optical path of the detector unit,
in order to center the image.
[0012] According to the invention the correction device has the
advantage that a simple compensation or correction of errors
developing in the image of the optical arrangement is possible.
Especially simple environment or system temperature, radiation used
by changeable or mobile elements in the arrangement, color defects
due to wavelength or wavelength ranges can be corrected. Thereby
depending on requirement a tipping and/or a swiveling plate with
one axle can be sufficient. If one would like to plan a two axle
parallel misalignment, one can either use two axle tipping and/or
swiveling plates, or one can plan a two plate arrangement, one axle
tipping and one swiveling. It is essential to the invention that
the plane parallel plate can be tipped with the mounting plate in a
defined and known way in the light path. For a two-axle adjustment
each combination of tipping and swiveling is suitable. A
combination of a tipping and swiveling movement is mechanically and
relatively simple to realize and has surprisingly no disadvantages
despite the shifting of the plane parallel plate along the Z-axis
that arises during the swiveling.
[0013] The correction brought about by the device can be done by a
user manually, e.g. with an adjustment in the works. However,
further training with a servo unit is particularly preferable,
which records at least one operating parameter of the optical
arrangement and which adjusts the tipping situation depending on
the value of the operating parameter. The tipping situation can be
put into calibration tables, for example. Also it is possible to
optimize a correction by adjusting the tipping situation via active
automatic control loops permanently and regularly or on
requirement. For such an arrangement it is preferential to plan an
automatic control loop that uses the tipping situation of the plate
as correcting variable, in order to balance the described effects
on the imaging optical arrangement. So, a possibly existing
temperature or long-term drift error can be balanced in a simple
manner in the optical arrangement.
[0014] Since it is well known that the parallel misalignment by a
plane parallel plate depends on the refractive index of the
transparent disk material, color transverse errors can develop by a
wavelength dependent parallel misalignment due to a dispersion of
the disk material in polychromatic radiation in the light path of
the optical arrangement. By structuring the plane parallel plate
from one or several sub panels one can compensate such color
transverse errors caused by the plane-parallel plate.
[0015] According to the invention the correction device can be also
adjusted for the correction of varying color transverse errors of
the optical image that are dependent on the operating conditions.
For example, if an optical arrangement is able to work with
different wavelengths then a wavelength-dependent and thus
operating condition-dependent color transverse error can occur.
According to invention the correction device can then adjust the
plane parallel plate depending on the wavelength range used in the
optical arrangement and the resulting color transverse errors, so
that in the final result despite operation with different
wavelength ranges an unchanged optical image is focused in the
arrangement. Naturally for this correction again, as previously
mentioned, a suitable servo unit can be used, which can also
exhibit an automatic control loop.
[0016] The requirements of the accuracy or sensitivity, with which
the drive handles the mounting plate, can also be preset, like the
acceptable parallel misalignment range via the thickness of the
plane parallel plate.
[0017] The correction device according to the invention reduces, as
previously mentioned, the requirements of adjustable optical
elements in the focusing optical arrangement. This advantage is
particularly important in the case of the already mentioned
confocal microscope. In a confocal microscope a selected specimen
area (Spot) is usually lit up and focused on a confocal slit in
form of a so-called pinhole objective, followed by a detector. The
radiation transmitted by this slit arrives with or without
intermediate image on a detector; the detector can also serve as a
confocal slit. The illumination can happen in a linear or
punctiform pattern.
[0018] Care must be taken to focus the specimen area completely on
the confocal slit plane in the pinhole objective. This is above all
made more difficult by the fact that a confocal microscope exhibits
regularly exchangeable beam splitters, with which an adjustment of
the microscope for different applications takes place, i.e. a
change of the irradiated or selected wavelengths. The optical
elements capable of being activated individually are accompanied by
tipping or wedge errors, which can be reduced only with large
effort in such a way that they do not disturb the image in the
microscope. The same applies to changes of temperature or of
long-term drift. The correction device according to the invention
permits the realization of a confocal microscope, with which errors
caused by changing optical elements can be simply corrected without
interfering with the optical image. Additionally, the correction
device can also be adjusted between the confocal slit and detector
and so the optical path between slit and detector can be corrected
suitably.
[0019] Although in the case of confocal microscopes that use a
pinhole objective before a locally non-resolving detector for
detection, the correction already facilitates the mechanical
requirements regarding the optical elements capable of being
activated, the saving of effort is particularly noticeable, if the
confocal microscope covers a locally disintegrating detector. This
is for example the case with line-scanning laser scanning
microscope that uses a slit diaphragm as pinhole slit before a
detector line. It is then possible, to balance via a corresponding
adjustment of the tipping situation of the plane parallel
transparent plate, both a compensation of deviations perpendicular
to the slit diaphragm and also a compensation of deviations
parallel to the slit diaphragm.
[0020] In the first case it is guaranteed that the light coming
from the specimen meets the slit diaphragm accurately and is not
off-center above or below the slit diaphragm. In the second case it
is guaranteed that the light coming from the specimen meets the
line detector correctly and there is no pixel misalignment between
pictures of two detection channels in the system, each exhibiting
its own line detector for example. Thus the confocal microscope
according to the invention can reach a sub pixel accurate image
registration during multi-channel training.
[0021] The problem with a slit diaphragm that deviates
perpendicularly to the direction line is solved in the confocal
microscope by the fact that now a narrow detector line can be used,
without necessitating a movement of the slit diaphragm and
detector. The unnecessary loss of light flux and the consequent
reduction of the signal-to-noise ratio in case of a misalignment
(caused by tipping and wedge errors of changeable elements) with a
lowering following an increase in resolution of the slit diaphragm
can be avoided.
[0022] Since the tipping or wedge errors of optical elements that
can be activated individually are usually reproducible, the tipping
situation of the transparent plane-parallel plate can be selected
in a simple manner. With change of an optical element that can be
activated, only a definite drive action of the plane parallel
transparent plate is necessary in order to adjust the tipping
situation newly required for the desired configuration of the
microscope. Therefore a further training of the microscope
according to the invention is preferential, in which the change or
adjustable elements in the light path are provided and which
records the submission and a configuration of change or adjustable
elements as operating parameters and adjusts the tipping situation
to be dependent on the value of the operating parameter.
[0023] An example of such a parameter, with which not only the
misalignment of the optical image in relation to the pinhole slit
but also a color transverse error is balanced, favorably provides
for the usage of radiation of different wavelengths in the optical
path of the microscope whereby the servo unit records the
wavelength in the light path as the operating parameter and adjusts
the tipping situation accordingly. Then for a confocal spectral
multi-channel microscope one or more plane-parallel plates are
first placed before the detector for each detection channel and the
tipping situation of the plane-parallel plate is adjusted by the
servo unit to be also dependent on the wavelength and/or the
wavelength range of the plate directed toward the detector in the
current channel.
[0024] One gets to use a confocal microscope comfortably, if an
automatic control loop is provided that maximizes the radiation
intensity at the detector unit, and/or minimizes the picture
misalignment by adjusting the tipping situation of the
plane-parallel plates as a correcting variable. Thus long-term
effects or temperature changes involving misalignments can be
corrected at any time without a service technician.
[0025] Therefore an implementation is preferential, with which the
aperture diaphragm and the detector unit are trained as confocal
split diaphragm and as detector line respectively and whereby the
tipping situation of the plane-parallel plate is two axle adjusted
such that the picture of the slit diaphragm is centered two-axle on
the detector line.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] The invention is further described below with reference to
the figure as an example. The figures illustrate:
[0027] FIG. 1 a schematic representation of a detector arrangement
of a laser scanning microscope,
[0028] FIG. 2 a schematic representation clarifying the need for
correction during the detector arrangement of FIG. 1,
[0029] FIG. 3 a schematic representation of a plane parallel plate
in the detector arrangement of FIG. 1, and
[0030] FIG. 4 a perspective representation of the plane-parallel
plate of FIG. 1 with motor drive.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0031] FIG. 1 shows schematically a detector arrangement 1 for a
Laser scanning microscope. The detector arrangement 1 exhibits a
CCD line 2, which is merged via a color splitter 3 into the light
path of the (not represented further) laser scanning microscope.
The color splitter 3 is changeable, in order to be able to record
radiation of different wavelength ranges with the detector
arrangement 1. The adaptability by the changeable color splitter 3
can be given regarding the (excitation) radiation used in the laser
scanning microscope and also regarding (fluorescence)
radiation.
[0032] The CCD line 2 receives radiation via the color splitter 3,
which falls on the CCD line 2 by a slit diaphragm 4 working as
aperture diaphragm.
[0033] The slit diaphragm 4 forms a pinhole objective of the
detector arrangement 1 together with an afore-arranged round optics
5 as well as a likewise afore-arranged first cylinder lens 6 as
well as a subordinate second cylinder lens 7, whereby the pinhole
is realized here by the slit diaphragm 4. Thus the laser scanning
microscope is a line scanning microscope, in which a confocal or at
least partly-confocal imaging of a rectangular or linear range
(line) of a specimen takes places by means of the pinhole objective
and/or the detector arrangement 1 on the CCD line 2.
[0034] The specimen is illuminated for fluorescence excitation,
which is confocally imaged, is schematically represented as
specimen field 10 in FIG. 1. In order to avoid an unwanted
detection of excitation radiation reflected in the system at the
CCD line 2, another barrier filter 8 having suitable spectral
characteristics is connected before the second cylinder lens 7, in
order to let only desired fluorescence radiation arrive at CCD line
2.
[0035] A change in the color splitter 3 or the block barrier filter
8 brings about inevitably a constant tipping or wedge error while
turning. The color splitter can inject an error between specimen
line 10 and slit diaphragm 4, barrier filter 8 can inject an error
between slit diaphragm 4 and CCD line 2. In order to prevent the
need for a readjustment of the situation of the slit diaphragm 4
and/or the CCD line 2, a plane-parallel plate 9 is arranged between
the round optics 5 and the slit diaphragm 4, i.e. in the image beam
path between the specimen field 10 and CCD line 2 which can be
brought into different tipping positions under the control of the
controller C. The plane-parallel plate 9 is attached in a suitable
(not represented in FIG. 1) mounting plate, which will be described
later in FIG. 4.
[0036] The plane parallel plate 9 causes a parallel misalignment,
which is drawn in FIG. 1, of the Z-axis OA. This parallel
misalignment can be seen schematically also in FIG. 3, which
concerns (described later) an implementation form of a two-part
plane-parallel plate 9. The luminous beams E diagonal to plate 9
breaking in to the disk surface withdraw as transferred luminous
beams A. Without plane-parallel plate 9 there would be the falling
beam, drawn dashed in FIG. 3.
[0037] A change of the tipping position of the plane-parallel plate
9 makes it possible to adjust the situation of the specimen line
opposite the slit diaphragm 4 (as well as with the usage of the
plate 9 after the slit diaphragm alternatively also the situation
of the slit diaphragm 9 to the CCD line 2 acting as slit) such that
for given conditions in the light path, which may themselves change
by changes of the color splitter 3, always an optimal, i.e. two
axle centered situation is given. This is illustrated in FIG. 2,
which shows the projection of the slit diaphragm 4 to the specimen
line 10 in plan view. As illustrated, due to a tipping or a wedge
error, which can be caused by for example by the color splitter 3
or the barrier filter 8, a misalignment dx adjusts itself in
x-direction dx and a misalignment dy in the y-direction between
slit diaphragm 4 and specimen line 10.
[0038] The consequence of misalignment dx is that the
signal-to-noise ratio is unnecessarily worsened. If one would like
to improve the dissolution of depth in the confocal microscope by
lowering the slit diaphragm 4, i.e. by reducing its expansion in
x-direction, it can happen that with a misalignment dx, which is
larger than the half height of the specimen line 10 no more
radiation arrives at the CCD line. The misalignment dx has then the
consequence that the dissolution of depth attainable with the laser
scanning microscope is actually smaller than is actually attainable
with the equipment. The same applies to the alternative or
cumulative variations in the adjustment of split diaphragm 4 and
CCD line 2.
[0039] The adjustment of the specimen field 10 in relation to the
slit diaphragm is attained by adjusting the tipping situation of
the plane parallel plate 9 such that no surface ranges of the CCD
line 2 remain unnecessarily unirradiated when seen in
x-direction.
[0040] On the other hand the misalignment dy causes the fact that
the local information recorded in y by the CCD line 2 does not
correspond to the actual emission or reflection conditions at the
specimen field 10. Artifacts or a misalignment in the image can be
the result. The adjustment of the tipping situation of plate 9
makes it possible to minimize the misalignment dy preferably even
bringing it to zero so that the split diaphragm 4 is centrically on
the CCD line 2 and is pixels of the CCD line 2 are correctly
illuminated. This is important in particular if the laser scanning
microscope exhibits several detector arrangements 1, which select
different color channels via different color splitters 3. Since due
to the individual adjustments of the detector arrangements 1 with
their color splitters 3 different misalignments dy would be
present, an error would be the result in such a multi-channel laser
scanning microscope in the allocation of the individual color
channels in a compound picture.
[0041] Depending upon wavelength or wavelength range evaluated in
the detector arrangement 1, the pinhole objective of the detector
arrangement 1 can exhibit a different color transverse error. Same
applies to the elements arranged before detector arrangement 1, for
example the color divisor 3 or other optics lying on the Z-axis OA.
By the adjustment of the tipping situation of the plate 9 this
color transverse error can be compensated purposefully. The
controller C steers plate 9 in a tipping situation, whereby each
one in the wavelength range and/or each wavelength, for which the
detector arrangement 1 can be used, is assigned with its own
tilting situation.
[0042] If in the detector arrangement 1 relatively wide-band
radiation is guided, the plane parallel plate can cause a color
transverse error, if the dispersion of the transparent material of
the plane-parallel plate 9 is such that a wavelength-dependent
misalignment of the failing ray bundle A is opposite to the
incident luminous beam E. For compensation the structure of the
plane parallel plate 9 represented in FIG. 3 consists of two sub
panels 9a, 9b. The materials of these sub panels 9a, 9b are
different and selected in such a way that in the wavelength range,
for which the detector arrangement 1 is appropriate, dispersion
caused by color transverse errors if possible cancel themselves.
For example the subpanel 9a causes for shorter wavelengths a
stronger misalignment than the sub panel 9b; the reverse applies to
longer wavelengths. Thus a compensation of the color transverse
error of the plane-parallel plate 9 is attained. For the production
of an color-independent or aimed color-dependent parallel
misalignment also two separated tippable plates with diversion
moving in opposite directions and from materials with different
dispersion can be used.
[0043] The controller C adjusts the tipping situation of the plate
9 to the default of a user, after evaluation of the current
configuration (in particular also environment or equipment
temperature or other external measured variables) of the Laser
scanning microscope or in continuous or intermittently running
control procedures. In the case of a regulation the tilting
situation of the plate 9 is used as correcting variable. As
regulated size the radiation intensity or the picture misalignment
on the CCD line 2 can be evaluated in a calibration step.
[0044] The drive 11 steered by the controller 9 is represented in
FIG. 4. As illustrated, the plane-parallel plate 9 is adjusted by
means of two stepping motors 12, 13 by the x and/or y axis. The
adjustment of the x-axis is a tipping motion with an axis of
rotation in the center of plate 9. The turn around the y-axis is a
swiveling around an axle lying outside of the plate.
[0045] For tipping around the x-axis a retaining plate 14 is
provided, onto which a pair of leaf springs 5 is screwed, which
fasten a framework 16, in which the plane-parallel plate 9 is
provided. The leaf springs 15 specify the tipping axle. They press
one roll 17 fastened at the framework 16 on a cam disc 18, which is
propelled by the stepping motor 12, which likewise sits on the
retaining plate 14. Depending on position of the cam disc 18 the
role 17 and the framework 16 are thus steered differently, by which
the tipping of the plate 9 is attained around the x-axis.
[0046] The retaining plate 14 is for its part an arm of a lever 19,
which is swiveling around a drag axis 20. The drag axis 20
represents the axle for the movement of the plate 9 around the
y-level. The other arm 21 of the lever 19 carries a role of 22 at
its end, which rests against a cam disc 23, which is propelled by
the stepping motor 13. Just as the leaf springs 15 press the role
17 on the cam disc 18, a spring element is intended at the drag
axis 20, which presses the role 22 on the cam disc 23.
[0047] By control of the stepping motors 12, 13 the controller C,
which is connected via not any further illustrated lines with the
stepping motors, can adjust the tipping and/or swiveling situation
of the plane parallel plate 9 in the light path of the detector
arrangement 1 using the motor. By the incremental control of the
stepping motors 12, 13 the current position of the plate 9 at each
point of period of operation is well-known to the controller C in
combination with a reference position started at the operating
beginning, so that the position of the plate 9 can be used in an
automatic control loop can be used as correcting variable and/or
can be adjusted in accordance with stored defaults.
* * * * *