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CN-121995613-A - Objective lens unit for a microscope, microscope comprising an objective lens unit, and method for setting an object plane of a microscope

CN121995613ACN 121995613 ACN121995613 ACN 121995613ACN-121995613-A

Abstract

An objective unit (6) for a microscope comprising at least one optically detectable target (48) on at least one optical component of the objective unit. The at least one optically detectable target has a well-defined position relative to the distal front end (62) of the housing of the objective unit (6) or the distal end of the microscope, respectively. An adjustable lens (65) of the objective lens unit is adjusted to clearly image at least one of the at least one optically detectable target, for example on a sensor attached to a camera of the microscope. Thus, the settings of the adjustable lens for the reference object plane are determined. The adjustable lens is then adjustable to move the object plane a distance in a distal direction, such that the object plane is arranged in the sample volume (100) at a desired position distally from the distal front end (62) of the housing of the objective unit (6) or the distal end of the microscope, respectively, by a distance(s).

Inventors

  • S. Link
  • R. Garty

Assignees

  • 梅特勒-托莱多有限公司

Dates

Publication Date
20260508
Application Date
20251103
Priority Date
20241104

Claims (14)

  1. 1. An objective unit (6) for a microscope (1), The objective unit (6) comprises a housing having a distal front end (62), The front optical aperture (63) of the objective unit is arranged in the distal front end (62) of the housing, The objective unit (6) further comprises an objective system (65, 66), the objective system (65, 66) being arranged inside the housing (61) and being located proximally of the front optical aperture (63) of the objective unit, Wherein the objective system (65, 66) is configured to be able to collect light received through a front end optical aperture (63) of the objective unit, Wherein the objective system (65, 66) comprises an adjustable lens (65), The objective unit (6) further comprises at least one optical component (64, 641, 642) located distally of the adjustable lens, wherein at least one optically detectable target (48) is provided on the at least one optical component (64).
  2. 2. Objective unit (6) according to the preceding claim, wherein the adjustable lens (65) is a motor-free automatic adjustment lens, In particular, the motor-less automatic adjustment lens (65) includes one of an adjustable lens and a lens that is axially displaceable along an optical axis of the objective lens unit (6) by a piezoelectric actuator.
  3. 3. Objective unit (6) according to any one of the preceding claims, wherein the at least one optically detectable target (48) is provided on a planar surface extending perpendicular to an optical axis of the objective unit (6).
  4. 4. The objective unit (6) according to any one of the preceding claims, wherein an immersion lens (64, 642) is arranged distally of the adjustable lens (65) and is configured to be able to receive light through the front end optical aperture (63).
  5. 5. The objective unit (6) according to any one of the preceding claims, wherein at least one of the at least one optically detectable target (48) is provided on a distal-most part (64, 641) of the objective unit (6).
  6. 6. Objective unit (6) according to the preceding claim, wherein the most distal optical component (64, 641) of the objective unit (6) is one of an immersion lens and a window closing the front optical aperture.
  7. 7. Objective unit (6) according to one of the preceding claims, wherein at least one of the at least one optically detectable target (48) has a three-dimensional shape.
  8. 8. The objective unit (6) according to any one of the preceding claims, wherein the objective unit (6) comprises at least one first optically detectable target and at least one second optically detectable target, wherein the at least one first optically detectable target and the at least one second optically detectable target are provided at different axial positions.
  9. 9. Objective unit (6) according to one of the preceding claims, wherein the housing (61) comprises a cap (611) and a sleeve (612), Wherein the objective system (65, 66) is arranged inside the sleeve, The cap comprising a lateral sheath, a front wall, a rear port, and the at least one optical component (641, 642), -Wherein a front optical aperture (63) of the objective unit (6) is provided in a front wall of the cap, and Said at least one optically detectable target (48) being provided on at least one optical component (641, 642) of said cap, -Wherein the sleeve (612) is at least partially received inside the cap (611), or wherein the cap (611) is at least partially received inside the sleeve (612).
  10. 10. Cap (611) configured for an objective unit (6) according to the preceding claim, wherein, The cap comprises a rear port, a front wall, a lateral sheath extending axially from the front wall, Wherein a front optical aperture (63) is formed in the front wall, Wherein the lateral sheath is configured to receive a sleeve (612) therein, wherein the sleeve is insertable in an axial direction through a rear port of the cap, or the lateral sheath is configured to be received in the sleeve (612), wherein the lateral sheath is insertable in an axial direction into the sleeve, -The cap comprises at least one optical component, and wherein a most distal optical component of the at least one optical component closes the front optical aperture (63), and -Wherein at least one optically detectable target (48) is provided on at least one of the optical components.
  11. 11. Cap (611) according to the preceding claim, wherein at least one of said at least one optically detectable target (48) is provided on the most distal one of said at least one optical component.
  12. 12. Microscope comprising an objective unit (6) according to any one of claims 1 to 9 and an optical sensor (52), wherein the optical sensor (52) is functionally coupled to the objective unit (6) to receive light transmitted from a front end of the objective unit (6) and through the objective system (65, 66).
  13. 13. A method for setting an object plane of a microscope (1), Wherein the microscope comprises at least one optical sensor (52) and at least one adjustable lens (65), -Wherein the at least one adjustable lens (65) is configured to enable an axial displacement of an object plane of the microscope relative to a distal end (11) of the microscope, wherein the object plane is a plane in which objects are clearly imaged on the at least one optical sensor (52), And wherein, in addition, at least one optically detectable target (48) is arranged in a region imaged on the optical sensor (52) and at an axial position determined with respect to the distal end (11) of the microscope, -The method comprises the steps of: a. Defining an expected object plane position relative to a distal end (11) of the microscope, the expected object plane position being located distally at an expected distance from the distal end (11) of the microscope, B. Adjusting the at least one adjustable lens (65) until the at least one optically detectable target (48) is clearly imaged on the optical sensor (52), and C. the at least one adjustable lens is adjusted to move the object plane axially along the optical axis of the microscope to the desired object plane position.
  14. 14. The method according to the preceding claim, wherein, A. Using two focus targets arranged at different axial positions, said two focus targets being arranged in a region imaged on the optical sensor and having a known axial distance (D) from each other, B. Wherein the two focus targets are provided by: i. At least one of the at least one optically detectable targets (48) has a three-dimensional shape and comprises at least two optically distinguishable features having a known axial distance from each other, each of these features forming one of the at least two focused targets, And/or At least one first optically detectable target (48) is located at a first axial position and at least one second optically detectable target (48) is located at a second axial position, wherein the first axial position and the second axial position are at a known axial distance from each other, the first optically detectable target (48) and the second optically detectable target (48) each forming one of the two focused targets, C. the method comprises the following steps: i. A first calibration adjustment is performed by adjusting the at least one adjustable lens (65) until a first one of the focus targets is clearly imaged on the optical sensor (52), Performing a second calibration adjustment by adjusting the at least one adjustable lens (65) until a second one of the focus targets is clearly imaged on the optical sensor (52), Determining an adjustment calibration difference as an amplitude of an adjustable lens adjustment applied to move the object plane from the first focus target to the second focus target Jiao Babiao, Determining the adjustable lens adjustment amplitude required to set the object plane to the desired object plane position according to the following parameters: The adjustment is performed in response to the calibration difference, An axial distance between a first one of the focus targets and a second one of the focus targets, and An axial distance between a first or second one of the focus targets and the intended object plane position, And adjusting the at least one adjustable lens by applying the desired adjustable lens adjustment amplitude to set the object plane to the desired object plane position.

Description

Objective lens unit for a microscope, microscope comprising an objective lens unit, and method for setting an object plane of a microscope Technical Field The subject matter claimed herein relates generally to instruments and methods suitable for microscopy. More particularly, the invention relates to the subject matter set forth in the claims. Background In certain applications of microscopy, it is desirable to position the object plane of the microscope (i.e. the plane in which the object is clearly imaged) at a distance in front of or distally from the front or front optical aperture of the microscope, whereas there is no object available for reference during the object plane positioning. This is typically found in, but not limited to, in-line and in-situ microscopy, particularly as the object to be observed passes through the sample volume. In that case, for example, there is no stationary object that can be focused on. A typical (but again non-limiting) example is cytometry, in particular image cytometry of biological processes. Biological processes are processes that use whole living biological cells or components thereof (e.g., bacteria, enzymes, or chloroplasts) to obtain a desired product. The biological process is usually carried out in a bioreactor, i.e. a process vessel, which is preferably a reusable and thus sterilizable tank or a disposable bag. Biological cells as part of the biological process are distributed in a liquid medium to create a suitable environment for the desired process. Typically, the culture medium contains nutrients for e.g. the cells in question and the gases they require, e.g. O 2 and CO 2. In most cases it is important to ensure that no other cells than those involved in the biological process are present in the bioreactor, which means that it is preferable to maintain a sterile barrier as long as possible between the process and the outside, thereby minimizing the number and duration of instances where unwanted cell contamination may occur. Generally, biological processes use devices to mix cells and culture medium continuously. Examples of such means are a stirrer arranged inside the bioreactor or a vibrator moving the whole bioreactor. Thus, in general, cells suspended in a medium move within a bioreactor. In many cases, the culture medium is closely monitored to ensure that the desired conditions are maintained. For such monitoring, a variety of optical, photochemical and electrochemical sensors are currently available and in use, which are capable of measuring in a reliable manner, for example, pH or dissolved oxygen content, on-line or in situ. However, there is currently no similar reliable measurement device available for directly monitoring cells. In-line or in-situ measurements-in the case of processes, in particular biological processes-are measurements which are carried out directly in the reactor, correspondingly in the bioreactor or in the line conveying the fluid to be monitored. In particular, the fluid to be monitored is a liquid of a biological process comprising a culture medium and biological cells. Cytometry is applied to characterize living or dead biological cells and preferably, for the use of the image cytometry of the present invention at hand, the cells to be characterized are provided in a liquid. For example, the density, size and morphology of biological cells can be determined by microscopy. In the absence of a reliable and quantitative on-line measurement method, a bioengineering must collect samples to perform cytometry using an off-line measurement device. This requires that sample volumes be taken from the bioreactor at specific time intervals, which increases the risk of contamination. Furthermore, this is time consuming and due to the sparse time intervals, the operator cannot obtain sufficient statistics and real-time information about the cytometry. An online cytometer that characterizes biological cells typically cultured in a liquid environment would significantly reduce complexity compared to an offline method, and would allow a process controller to monitor cell counts and cell characteristics (such as those mentioned above) in near real-time. In some applications, the sample volume in which the object is clearly imaged may be defined optically: In the first dimension, the sample volume may be optically defined by the depth of field of the microscope. Preferably, the depth of field of the microscope is determined by the objective unit. In two dimensions perpendicular to the first dimension, it is the imaging region that optically defines the sample volume, e.g. determined by the field of view of the microscope, e.g. defined by the size of an optical sensor attached to the microscope or by an aperture (e.g. front end optical aperture) arranged in the optical path. It is also possible to define the imaging region after the image is obtained, for example by suitable cropping or by selecting appropriate sub-regions in the obtained i