DE202008006065U1 - Arrangement for controlling the movement of optical assemblies in a microscope - Google Patents

Abstract

Arrangement for positioning optical components, in particular lenses, lens groups (L1 ... L4), apertures with constant or variable apertures, prisms or mirrors along the optical axis of a variable imaging system, comprising:
At least one optical component which can be displaced in the direction of the optical axis into a plurality of desired positions,
- An electronically controllable drive device coupled to the optical component, and
- A drive unit connected to the drive unit, wherein
- The drive unit has a memory in which set values for the desired positions in association with characteristics of the imaging system, preferably in association with the magnification, are stored, and wherein
- The drive unit with a command input unit (BE) is connected, which is designed to specify a characteristic and thus to trigger a shift of the optical component in a desired position corresponding to this characteristic.

Description

The The invention relates to an arrangement for positioning optical Components, in particular of lenses, lens groups, apertures with a constant or variable aperture, prisms or mirrors the optical axis of a variable imaging system in a microscope, including in particular in a macroscope.

Under The term macroscope in the sense of this invention is a microscope to be understood by a large zoom range for observation of Objects at high working distance and in large Visual fields is characterized. The inventive Arrangement is advantageously for the variation of characteristics the required imaging systems suitable, such as variation of the magnification, the resolution, the visible Object field, the depth of focus or the focus position.

microscopes, including in particular dual-channel stereomicroscopes or higher resolution, single-channel Macroscopes, the large working distances and large Provide object fields are used as observation instruments in manipulation and control tasks are used, in which the user often in both Hands holding instruments. Therefore, the operating functions "Zoom" and "focusing" in such modern microscopes basically motorized, and the control is mainly via a footswitch or other separate, ergonomically designed Controls made.

To optical components with motor driven movements in Zoom or focusing systems and the required controllable Drives are already various solutions known.

Classic solutions for motorized zoom drives, for example, for stereomicroscopes, surgical microscopes or macroscopes, use to control the movement of the optical elements concerned mathematically predetermined, formed on discs two-dimensional or drums trained three-dimensional curves. Thus, for example, in the macroscope systems Z6 APO A and Z16 APO A from Leica Microsystems, Germany, lens elements are moved according to a guiding principle that is also used in EP 1 510 846 A1 is described and in which a movement control provided for drum curve is connected via mechanical transmission elements with a drive motor.

Such arrangements are disadvantageously not only expensive and expensive, it is due to manufacturing and wear-related tolerances and only a limited accuracy achievable. The principle of such a solution is in 1 shown using the example of a macroscope.

Unlike in contrast EP 0 646 769 A1 , where a method and an arrangement for optical focus control are described under the title "displacement measurement apparatus having first and second servo control circuits and a zone decision circuit", in which the displacement of an objective lens is realized by means of electric linear drive.

In US 5,258,798 A and US 5,612,740 A Linear drives are also provided, but in connection with zoom systems. With US 5,365,296 A The design and operation of special piezoelectric linear drives for both the drive of zoom and autofocus systems is proposed.

Also These solutions cited above are due to their still high proportion of precision mechanical assemblies relatively expensive and expensive and also tolerant.

From Based on this prior art, the invention has the object underlying, a little expensive, while cost feasible and high accuracy principle for the movement optical components in variable imaging systems.

• – mindestens eine in Richtung der optischen Achse in mehrere Sollpositionen verschiebbare optische Komponente,
• – eine mit der optischen Komponente gekoppelte elektronisch ansteuerbare Antriebseinrichtung, und
• – eine mit der Antriebseinrichtung verbundene Ansteuereinheit, wobei
• – die Ansteuereinheit über einen Speicher verfügt, in welchem Einstellwerte für die Sollpositionen in Zuord nung zu Kenngrößen des Abbildungssystems, vorzugsweise in Zuordnung zum Abbildungsmaßstab, gespeichert sind, und wobei
• – die Ansteuereinheit mit einer Befehleingabeeinheit verbunden ist, die ausgebildet ist zur Vorgabe einer Kenngröße und damit zum Auslösen einer Verschiebung der optischen Komponente in eine dieser Kenngröße entsprechende Sollposition.

According to the invention, the object is achieved with an arrangement for positioning optical components, in particular lenses, lens groups, apertures with constant or variable apertures, prisms or mirrors on the optical axis of a variable imaging system, comprising:

• At least one optical component which can be displaced in the direction of the optical axis into a plurality of desired positions,
• - An electronically controllable drive device coupled to the optical component, and
• - A drive unit connected to the drive unit, wherein
• - The drive unit has a memory in which set values for the desired positions in association with characteristics of the imaging system, preferably in association with the magnification, stored, and wherein
• - The drive unit is connected to a command input unit, which is designed to specify a characteristic and thus to trigger a shift of the optical component in a target position corresponding to this parameter.

In the context of the invention, for example also embodiments in which the set values for the target positions are not only stored in association with the imaging scale of the imaging system, but also in association with parameters such as resolution, visible object field, depth of field, percentage light intensities or focus position.

Advantageous in terms of minimizing storage capacity also embodiments in which the drive unit with an arithmetic circuit is equipped to determine currently set parameters like magnification, resolution, visible object field, Selective focus, percentage light intensities or Focusing position depending on the for the optical components predetermined target positions.

• – zum Messen einer real eingestellten Kenngröße,
• – zur Korrektur von Abweichungen zwischen dem Istwert einer Kenngröße und dem Sollwert einer Kenngröße durch Änderung von Position der optischen Komponente, bis der Sollwert der Kenngröße eingestellt ist, und
• – zur Speicherung der Position der optischen Komponente als Sollposition in Zuordnung zu dem Sollwert der Kenngröße.

In one embodiment, which is particularly applicable for adjusting the positions of displaceable along the optical axis optical components in imaging systems, the inventive arrangement has a device which is formed

• - to measure a real set parameter,
• - To correct for deviations between the actual value of a parameter and the desired value of a characteristic by changing the position of the optical component until the target value of the characteristic is set, and
• - For storing the position of the optical component as a target position in association with the target value of the characteristic.

In order to is given a regulatory rating system by which the target positions be determined and stored. In later use These set positions determined in this way are then removed from the memory read out, according to the principle of control for the imaging system preset and set.

So are analogously apparatus- or system-corrected "virtual" Cams for the optical components in front of themselves be checked spontaneously at any time. Deviations detected during the check of the system parameters are stored by simple correction of Values can be compensated. In other words: if necessary the imaging system can be easily readjusted.

Furthermore There is a significant advantage in that as software present, the specifically executed imaging system assigned "virtual" cam at any time and arbitrarily can often be re-stored, for example, even if the control unit must be replaced. It's just necessary to keep a backup copy of the settings or call the manufacturer of the microscope.

Advantageous is the variable imaging system with two or more on the optical Axis sliding optical components equipped, and it can be a separate control of each individual optical component be provided. However, it is also conceivable to control at least two of the optical components together, which then at their Movement are rigidly coupled together.

When Control unit can be a personal computer (PC) and as Command input unit a PC keyboard connected to the PC, a PC mouse, a scroll wheel, a touchscreen slide or a microscope Be provided control.

Especially advantageous as drive devices direct motor linear drives, especially in the form of actuators or steppers provided.

From It is also advantageous if the inventive Arrangement is equipped with a display element on which a given and / or measured, d. H. real set Characteristic is given visually perceptible.

Farther It is recommended to change the position of the optical To cause components by means of the drive unit so that a linear change Δβ of the magnification β. It can with the change in position of the optical components also a uniform Zoomverstellgeschwindigkeit vβ be given and so the condition Δβ / Δt = constantly fulfilled.

Of the Invention is based on the idea on discs or drums, where the cams are formed, so at the same time as many as possible mechanical and faulty components for the transmission of motion to renounce and instead the movement of the optical components with the control of electrical direct drives, such. B. actuators or so-called "stepper", under direct drives For the purposes of the present invention, for example, linear drives with one of the desired precision of the position change to understand corresponding step resolution.

The interpolation points of the mathematically determined control curve, for example of a microscopic zoom system, which are available from the optical calculation, are stored as programmed values in memory elements, eg. As EPROM or PC storage media stored. When you press the electrical zoom control, the electric drives for simultaneously controls all displaceable components such that the components travel a different distance along the optical axis of the zoom system per unit of time depending on the mathematically determined curve. This is achieved, for example, when using stepper drives by specifying a different number of individual steps by means of the drive unit for the respective drives.

In order to reach the moving components in discrete steps, depending on the desired zoom resolution smaller or greater, theirs after optical Invoice or according to the corresponding data sheet Target positions.

Become whereas electric drives use regulated DC motors, is to achieve the desired positions at least one additional Measuring system required, which is the actual position reached detected, the detected value with the reached Compare target position and causes a correction, if the target position has not yet been reached. Such a principle of Control is technically more complex and slower than the invention Control without control loop and without required measuring system.

One Another advantage of the solution according to the invention is that the optical adjustment of the variable Imaging system can be done by means of electric drives, d. H. the predetermined mathematical setpoint curve, which is present in the memory can in single-step operation during optical system adjustment be changed.

For this For example, the zoom area is scrolled through and it is checked whether a possible Fokussierabweichung still within the Depth of field range is. This can be done by subjective Image assessment, or by objective measurement, for example via contrast measurement on a test object by means of a CCD camera in the imaging beam path or with a optical wavefront analysis, using wavefront sensors can be. In this way, high Justiergenauigkeiten possible, d. H. remaining focus deviations can almost completely eliminated.

If a focus deviation is detected, the adjustment values for the respective drives automatically or by manual executed correction changed so that the Deviation eliminated and thus the apparatus error is obo. The new settings for the respective drives are stored as nominal positions.

Especially advantageous is a highly accurate measurement, for example, the actual existing magnification and the comparison of the result with a given magnification and a subsequent magnification Correction of the values stored in memory for the target positions.

Such corrections are in conventional cam drives, as in 1 represented, not or only partially possible.

Lie the mathematically determined desired curves in the manner described stored before, the correction can be beneficial over one external computer, anyway for the factory system programming is used.

To the correction of an optical device error from the external computer from then the entry of a changed data record, in which the corrected function values or value pairs are taken into account are in a memory chip, which subsequently in the Microscope, preferably macroscope, is used. This will be for everyone executed microscope or macroscope individual and anytime, as necessary, correctable "virtual" Cams assigned and supplied to the user, so that opposite the devices equipped with mechanical curve control a new quality of adjustability and functional accuracy is reached.

This makes up for the greatly minimized defocus residual errors as well high-zoom systems in extremely sharp and high-contrast images highly accurate adherence to the reproduction scale and thus the magnification β over the entire zoom range noticeable and is of significant use for the users of the so equipped microscopes.

It it is known that high-speed systems have complicated curves, long adjustment paths and usually more than two movable lens groups and / or diaphragms and therefore with exclusively mechanical means only with very high technical effort or at all are no longer feasible. This problem is solved with the invention Arrangement solved.

The Invention will follow on the basis of embodiments explained in more detail. In the accompanying drawings demonstrate:

1 the schematic diagram of a zoom system according to the prior art

2 the schematic diagram of the zoom system according to the invention in an embodiment with mechanical motion compensation, wherein the individual optical components each ver separately are slidable,

3 the schematic diagram of the zoom system according to the invention in an embodiment with optical motion compensation, wherein predetermined optical components are rigidly coupled to each other,

4 the comparison of non-linearized and linearized zoom speed in a zoom system,

In 1 is a per se known from the prior art motorized drive for the zoom system of a single-channel macroscope shown schematically.

On a guide F are the lens groups L1, L2, L3 of the zoom system arranged. The lens group L3 is fixed here, the lens groups L1 and L2 are designed to be displaceable. The lens groups L1 and L2 are connected via joints G with a toggle lever system KH, the hinged via a pinch roller A to a cam KS is, the frame fixed to the macroscope housing (not graphically shown) is arranged.

The Lens group L1 is rigidly connected to a rack Z, which a seated on a motor shaft driving pinion R1 and a Pinion R2 is adjusted, d. H. about the rotary motor movement is coupled via the pinion-rack combination Lens group L1 shifted linearly. This movement is going on too transferred the coupled toggle lever system KH, in turn, the Lens group L2 set in motion.

by virtue of the waveform with which the cam KS is provided is the movement of the toggle lever system KH and thus the adjustment movement the lens group L2 with a non-linear mathematical function controlled as so-called mechanical motion compensation.

A first embodiment of a zoom system according to the invention with mechanical compensation, by way of example for a single-channel macroscope with a large zoom range, is shown in FIG 2 shown schematically.

in this connection 5 lens groups L1 ... L5 are arranged on a guide F. While the lens group L1 and L5 arranged fixed to the frame are, the lens groups L2, L3 and L4 according to defined curved paths moved and over the respective driver M, spindle nuts SM and spindles S of associated linear actuators LA1, LA2 and LA3 driven, which are located within the zoom system and arranged in parallel to the guide F extending directions are.

to Ensuring a precise run are the Linear drives LA1, LA2, LA3 each between the tips of the spindles S and the associated, fixed to the frame arranged engine bodies in alignment. Due to the rotation of the spindles S is by means of the respective spindle nut SM, a linear displacement of the lens groups L2, L3, L4 generated. The linear actuators LA1, LA2, LA3 are equipped with a Drive unit AE connected, in turn, with an input unit EE is related.

It lies within the scope of the invention, when the same linear movements the lens groups L2, L3, L4 with fixed spindles S and rotation-secured, moving with the respective associated lens group L2, L3 or L4 Motor bodies are generated.

A very advantageous embodiment of a single-channel zoom system according to the invention with optical compensation, also exemplary for a single-channel macroscope, is in 3 shown.

at In this embodiment, two movable lens groups L1 and L3 rigidly connected to each other via a coupling K. The coupling K is connected to a spindle nut SM, the from a spindle S, which is part of a linear actuator LA with fixed Engine body is driven.

Between the lens groups L1 and L3 can play compensation, z. B. over Tension spring, be provided. The four-limbed, shown here by The guide F aligned zoom system is in addition to the movable Lens groups L1 and L3 from the fixed lens groups L2 and L4, where L2 is located between L1 and L3. The mechanical-optical Adjustment of this zoom system, in contrast to the adjustment of Zoom systems with mechanical compensation not over the Linear actuator LA done because here due to their rigid coupling no relative movements between the lens groups L1 and L3 with the linear actuator LA can be generated.

Here For example, both rigidly coupled lens groups L1 and L3 are advantageous driven by the same mathematical linear or nonlinear control cam, the drive according to a linear cam with the so-called optical compensation takes place and the drive for a non-linear control curve corresponds to a drive with the mechanical compensation.

4 shows the comparison of non-linearized and linearized zoom speed in zoom systems.

Zoom systems according to the prior art with mechanical compensation and manual Bedie tion or with attached drive motor have a non-linear zoom scale due to the design. Rotation of the zoom button by an equal angle causes different magnifications of the magnification β, ie, the zoom speed vβ is not linear, and the change Δβ in the magnification β per unit time Δt is not constant, as shown in the upper graph in FIG 4 is apparent.

These Property of the zoom system is depending on the size nonlinearity, especially during manual operation for the user very getting used to and at the required precise setting of a defined Magnification β in zoom ranges with large changes the magnifications β at small adjustment paths barely practicable.

In the case of the zoom system according to the invention, by varying the individual lens group displacements, realized by the direct drives, a linearization of the zoom scale and thus an equalization of the zooming speed vβ (Δβ / Δt = constant) can be achieved by changing the individual lens group velocity profiles (cf. lower diagram in 4 ).

With that changes the magnification β per unit time by the same amount, d. H. the system is in the entire zoom range equally "sensitive." This is especially important the operation with an electrical control to a very sensitive magnification setting accuracy and thus gives a high benefit to the user, in particular in routine work.

For Zoom systems with mechanical compensation according to the prior art this property is feasible only with high technical effort, because of a coupling gear driving motor then a must have non-linear velocity profile.

In 4 For reasons of simplicity, the zooming speed has been represented on only a single lens group. However, this procedure is particularly applicable for zoom systems in which several lens groups are moved by direct motor drives, such as linear drives.

The zoom system according to the invention described above by way of example is particularly advantageously applicable in connection with a macroscope provided with motor drives. It can be a zoom system, as in 2 and 3 is exemplified, housed in the housing of the macroscope body and are driven via a connecting line.

At a arranged on the macroscope body display element can set parameters or operating states like zoom factor, magnification or magnification, Diameter of the visible object field, resolution, percentage light intensities or depth of field are visually perceptible.

To turning on the macroscope go through the electronics in the Drive unit and the linear drives initially an initialization phase, to find the zero points of the linear drives and the zoom drive for example, to the lowest magnification, preferably an overview magnification to drive.

A particularly advantageous and ergonomic operation of such Systems can be reached with a centrally arranged operating element, with all the essential system functions such as zoom, focus and light can be controlled from a single operating position.

optional is also an operation with a connected PC and its Keyboard possible, which is then preferably used, when at the macroscope taken by a digital camera Images should be displayed or processed by image analysis. at Manipulation tasks in which hands to operate of the macroscope are an alternative operation via footswitch advantageous, for example for adjusting the zoom and focus.

A

pinch

AE

control unit

EE

input unit

F

guide

G

joint

K

paddock

KH

Toggle system

KS

cam

L1 ... L5

lens group

LA, LA1 LA3 ...

linear actuator

M

takeaway

R1, R2

pinion

S

spindle

SM

spindle nut

Z

rack

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• EP 1510846 A1 [0005]
• EP 0646769 A1 [0007]
• - US 5258798 A [0008]
• - US 5612740 A [0008]
• - US 5365296 A [0008]

Claims (12)

Arrangement for positioning optical components, in particular of lenses, lens groups (L1 ... L4), apertures with a constant or variable aperture, prisms or mirrors along the optical axis of a variable imaging system, comprising: - at least a displaceable in the direction of the optical axis in a plurality of desired positions optical component, - one with the optical component coupled electronically controllable drive device, and - one drive unit connected to the drive device, wherein - the Control unit has a memory in which Setting values for the target positions in association with characteristic values of the imaging system, preferably in association with the magnification, are stored, and where - the control unit is connected to a command input unit (BE) formed is to specify a characteristic and thus to Triggering a shift of the optical component in one of this characteristic corresponding set position. Arrangement according to claim 1, wherein the setting values for the target positions in assignment to characteristic values like resolution, visible object field, depth of focus, stored percentage light intensities or focus position are. Arrangement according to claim 1 or 2, wherein the Control unit is equipped with an arithmetic circuit for detection of currently set parameters such as magnification, Resolution, visible object field, depth of focus, percentage light intensities or focus position as a function of the predetermined positions for the optical components. Arrangement according to one of the preceding claims, in which the variable imaging system with two or more on the optical axis sliding optical components equipped is and a separate control of each individual optical component is provided. Arrangement according to one of the preceding claims, in which the variable imaging system with two or more on the optical axis sliding optical components equipped is and a common control of at least two of the optical Components is provided. Arrangement according to one of the preceding claims with a device that is designed - to measure a real set parameter, - to Correction of deviations between the real set characteristic and a desired characteristic by change from positions of the optical components until the desired Characteristic is set, and - to Storage of the positions of the optical components as target positions in association with the desired characteristic. Arrangement according to one of the preceding claims, in which the imaging system is designed as a zoom system. Arrangement according to claim 7, wherein the position change of optical components a linear change Δβ of Mapping β is provided. Arrangement according to claim 7, wherein the position change of optical components, a uniform Zoomverstellgeschwindigkeit vβ provided and so the condition .DELTA..beta. / .DELTA.t = constant is fulfilled. Arrangement according to one of the preceding claims, wherein as a drive unit, a personal computer and as a command input unit a touchscreen attached to the personal computer, a PC mouse, a scroll wheel and / or a PC keyboard are provided. Arrangement according to one of the preceding claims, in which as drive means direct motor linear drives (LA), in particular in the form of actuators or steppers, are provided. Arrangement according to one of the preceding claims, equipped with a display element (AZ) on which the respective predetermined and / or the measured characteristic visually perceptible.