JP2008191489A - Immersion objective lens and microscope having the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an immersion objective lens capable of preventing contamination of the critical portions of an optical system, by taking contamination countermeasures against immersion liquid. <P>SOLUTION: The objective lens for immersion 1 is configured to include a cylindrical housing portion 5; a cylindrical lens holder portion 3 which is housed slidably in the housing portion; one or more magnets 17 which are provided in at least one of the inner circumferential surface in the vicinity of the top end portion of the housing portion and the outer circumferential surface of the lens holder portion facing the inner circumferential surface; and a magnetic fluid 19 which is arranged in the gap between the housing portion and the lens holder portion, in the vicinity of the magnet. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an immersion objective lens of a microscope and a microscope having the same.

Conventionally, when observing biological specimens with a microscope, the space between the specimen and the tip of the objective lens is filled with liquid, and the resolution is made larger than that of the objective lens itself. (Hereinafter, simply referred to as an objective lens) is used. In addition, in this objective lens, when the specimen and the objective lens collide accidentally, the lens barrel of the objective lens expands and contracts in the optical axis direction to prevent the specimen from being damaged, and the immersion liquid is outside the lens holding portion of the objective lens. One having a mechanism for preventing entry into the space between the lens barrel and the lens barrel has been proposed (see, for example, Patent Document 1).
JP 2003-185926 A

  However, the conventional objective lens has insufficient measures against contamination of the immersion liquid, and when the objective lens collides with the slide glass, the immersion liquid overflows and contaminates an important part of the objective lens optical system. There are challenges.

  In order to solve the above problems, the present invention provides a cylindrical housing portion, a cylindrical lens holder portion slidably accommodated in the housing portion, and an inner peripheral surface in the vicinity of the distal end portion of the housing portion. One or more magnets provided on at least one of the outer peripheral surfaces of the lens holder portion facing the inner peripheral surface; a magnetic fluid disposed in a gap between the housing portion and the lens holder portion in the vicinity of the magnets; An immersion objective lens is provided.

  In addition, the present invention provides an immersion objective lens for a microscope, wherein a cylindrical magnet is disposed in the vicinity of the tip lens of the objective lens.

  The present invention also provides a microscope having the immersion objective lens.

  ADVANTAGE OF THE INVENTION According to this invention, the objective lens for immersion which can take the contamination countermeasure with respect to immersion liquid and can prevent the contamination of the important part of an optical system can be provided.

  Hereinafter, an immersion objective lens (hereinafter simply referred to as an objective lens) according to an embodiment of the present invention will be described with reference to the drawings.

(First embodiment)
1A and 1B are schematic cross-sectional views of the objective lens according to the first embodiment. FIG. 1A shows a specimen observation state, and FIG. 1B shows a state where the objective lens collides with the specimen. Note that the reference numerals will be described only with reference to FIG. FIG. 2 is a schematic configuration diagram of a microscope having the objective lens according to the first embodiment.

  1 and 2, the objective lens 1 includes a cylindrical lens holder portion 3 that holds a lens (not shown) and a cylindrical housing portion 5 that holds the lens holder portion 3 slidably.

  The housing portion 5 includes a lower housing portion 5a having a screw portion 7 for screwing into the revolver 21 shown in FIG. 2, and an upper housing portion 5b screwed to the lower housing portion 5a on the screw portion 9 on the distal end side of the objective lens 1. It consists of and.

  The revolver 21 side of the lens holder portion 3 is formed with a diameter smaller than that of the tip end side, and the coil spring 11 is disposed in this portion. The movement of one end of the coil spring 11 is restricted by the end portion 3a on the revolver 21 side of the lens holder portion 3, and the other end is moved by the coil spring stopper 5c formed on the revolver 21 side on the inner periphery of the lower housing portion 5a. Limited. Further, the lens holder portion 3 is restricted in movement because the convex portion 3b formed on the outer peripheral portion on the distal end side of the lens holder portion 3 abuts on the protruding portion 5d formed on the inner peripheral portion of the upper housing portion 5b. The coil spring 11 is configured not to come out of the housing portion 5 due to the pressing force of the coil spring 11.

  The lens holder portion 3 is biased toward the distal end side along the optical axis by a coil spring 11. With this urging force, when the tip of the lens holder portion 3 collides with the slide glass 13 as shown in FIG. 1B, it is contracted toward the revolver 21 along the optical axis as indicated by an arrow. Moreover, when the front-end | tip part of the lens holder part 3 leaves | separates from the slide glass 13, it becomes possible to return the lens holder part 3 to the slide glass 13 side along an optical axis. As a result, it is possible to prevent the slide glass 13 from being damaged when the tip of the lens holder portion 3 collides with the slide glass 13.

  A concave groove 15 is formed on the inner peripheral portion of the upper housing portion 5b substantially over the entire circumference, and a ring-shaped permanent magnet 17 is fitted into the concave groove 15 and fixed by adhesion or the like. A magnetic fluid 19 is disposed between the permanent magnet 17 and the lens holder portion 3 so that the immersion liquid 41 does not enter between the lens holder portion 3 and the housing portion 5. Yes.

  As a result, even if the immersion liquid 41 dripped at the tip of the objective lens 1 leaks and falls along the outer periphery of the lens holder portion 3, it can enter the space between the lens holder portion 3 and the housing portion 5. Therefore, it is possible to prevent the sliding performance of the lens holder part 3 and the housing part 5 from deteriorating due to the immersion liquid 41 entering or drying. When the sliding performance deteriorates, when the tip of the lens holder 3 collides with the slide glass 13, an excessive load may be applied to the slide glass 13 and the slide glass 13 may be damaged.

  As described above, the objective lens 1 according to the first embodiment can prevent the immersion liquid 41 spilled by the magnetic fluid 19 from entering the objective lens, and thereby the lens holder portion 3 and the housing portion 5 can be prevented from entering each other. Sliding deterioration can be prevented. In the present embodiment, the magnet is installed in the groove, but if the magnet is formed in a thin plate shape, the groove is not necessary.

  FIG. 2 shows an inverted microscope 20 equipped with the objective lens 1 according to the first embodiment.

  In FIG. 2, the objective lens 1 is mounted on the revolver 21 of the inverted microscope 20 and is disposed below the stage 22. The specimen 23 arranged on the stage 22 is irradiated with illumination light through the illumination optical system 24, the transmitted light is collected by the objective lens 1, and the specimen image from the eyepiece lens 25 through the imaging optical system (not shown). Is observed. The revolver 21 is moved up and down by rotating the focusing handle 26, and the sample 23 is focused.

  In the inverted microscope 20 equipped with the objective lens 1 according to the first embodiment, the specimen 23 is focused after the immersion liquid 41 is dropped on the tip of the objective lens 1 in order to observe the specimen with high resolution. . At this time, even when the objective lens 1 collides with the specimen 23 (see FIG. 1B), as described above, the lens holder 3 of the objective lens 1 can be expanded and contracted to prevent the specimen 23 from being damaged. Further, even when the immersion liquid 41 overflows from the tip of the objective lens 1 and falls outside the objective lens 1 in the event of a collision, the immersion liquid 41 is separated from the lens holder portion 3 and the housing portion by the sealing action of the magnetic fluid 19. 5 can be prevented from entering.

(Second Embodiment)
Next, an objective lens according to a second embodiment and a microscope equipped with the objective lens will be described with reference to the drawings.

  FIG. 3 is an enlarged partial sectional view of the distal end of the objective lens according to the second embodiment in use. FIG. 4 is a schematic configuration diagram of an upright microscope equipped with an objective lens according to the second embodiment.

  3 and 4, the objective lens 30 has a ring-shaped concave groove 35 formed in the vicinity of the outer periphery of the portion on the slide glass 13 side of the cover 33 that supports the tip lens 31 of the objective lens 30. A ring-shaped permanent magnet 37 is fixed to the groove 35 by adhesion or the like.

  In the objective lens 30 according to the second embodiment, an immersion liquid 41 is disposed between the cover glass 39 and the tip lens 31 to enable high-resolution specimen observation. A magnetic fluid 19 supported by the permanent magnet 37 is disposed outside the area where the immersion liquid 41 exists, and is divided into an immersion area and other areas. The magnetic fluid 19 surrounds the immersion area corresponding to the shape of the permanent magnet 37 by dropping the specimen in the vicinity of the permanent magnet 37 after placing the immersion liquid 41 in the observation state with the objective lens 30. It becomes a ring-shaped wall.

  In general, when observing a biological specimen, water is often used as the immersion liquid 41. In the conventional observation state, water evaporates during observation. It is necessary to prepare a means to replenish. Further, when the immersion liquid 41 evaporates, there arises a problem that the tip lens 31 of the objective lens 30 remains dirty.

  In the objective lens 30 according to the second embodiment, the immersion area and other external areas can be separated by the magnetic fluid 19 so that the immersion area can be made substantially airtight, thus preventing evaporation of moisture. It becomes possible, and it is not necessary to prepare a means for supplying water.

  Further, since the magnetic fluid 19 is held by the permanent magnet 37, the relationship between the magnetic fluid 19 and the tip lens 31 is always maintained even if the specimen is moved in the XYZ directions within a limited range, so that the immersion to be observed is maintained. The liquid region can be maintained in an airtight state by the magnetic fluid 19. Further, if the objective lens of FIG. 3 is used in an inverted microscope, even if the immersion liquid spills from the position of the tip lens 31, it is stopped by the magnetic fluid 19, so that the objective lens 30 and the revolver mounting portion and the revolver are prevented from reaching. it can. In this way, by using the objective lens 30 according to the embodiment and making the immersion area almost airtight with the magnetic fluid 19, even when an immersion liquid that is volatile or easy to dry is used, it can be used for a long time. Can be realized without using replenishing means.

  In addition, it is desirable to use a component having no affinity between the fluid component of the magnetic fluid 19 and the component of the immersion liquid 41 used for observation. By doing so, it is possible to prevent the immersion liquid 41 and the magnetic fluid 19 from being mixed.

  In the above-described configuration, the permanent magnet 37 is disposed on the surface of the objective lens 30 on the side of the slide glass 13, but a ring-shaped permanent magnet is disposed on the outer peripheral portion of the cover portion 33 of the objective lens 30. However, the same effect can be achieved. For example, by fitting a ring-shaped permanent magnet 37 to the outer periphery of the cover portion 33 of the conventional objective lens, the magnetic fluid 19 can be disposed in the vicinity of the immersion area, and drying of the immersion liquid 41 is prevented. Can do.

  FIG. 4 shows an upright microscope 50 having the objective lens 30 according to the second embodiment. In the upright microscope 50, the objective lens 30 is supported by the revolver 51, and the focusing handle 54 is rotated to move the stage 52 up and down to focus on the specimen 53 placed on the stage 52. Illumination light from the lamp house 55 is irradiated onto the specimen 53 via an illumination optical system (not shown), condensed by the objective lens 30, and the specimen image is observed by the eyepiece lens 56 via the imaging optical system.

  The permanent magnet 37 provided on the objective lens 30 allows the magnetic fluid 19 to maintain the immersion area in an almost airtight state, so that the specimen 53 can be observed without supplying the immersion liquid 41 for a long time.

  The objective lens 30 according to the second embodiment may have a configuration that can be expanded and contracted similarly to the objective lens 1 according to the first embodiment. In this case, the expansion / contraction configuration is the same as that of the first embodiment, and a description thereof is omitted.

  FIG. 5 shows an example of a cross-sectional shape of a slide glass suitable for the objective lens 30 according to the second embodiment. FIG. 5A shows a state in which the magnetic fluid 19 is dropped and held on the slide glass, and FIG. The states of the magnetic fluid 19 in the observation state are respectively shown.

  In the second embodiment, since the slide glass 13 is flat and it is difficult to position and drop the magnetic fluid 19 in advance, it is dropped after the objective lens 30 is immersed in the immersion liquid. Explained when things are done.

  A slide glass 61 shown in FIG. 5A is formed with a substantially circular recess 62 for holding the magnetic fluid 19 around the immersion liquid 41. By dropping the magnetic fluid 19 in advance in the recess 62, the magnetic fluid 19 is attracted to the permanent magnet 37 in the observation state as shown in FIG. it can. By using the slide glass 61 having such a dent portion 62 together with the objective lens 30, it is not necessary to drop the magnetic fluid 19 after it is in the observation state, and the immersion area can be easily and efficiently sealed in terms of work efficiency. I can do it.

  The objective lens 1 also has the same effect as the second embodiment by disposing the ring-shaped permanent magnet 37 according to the second embodiment at the tip of the objective lens 1 according to the first embodiment. When the tip of the objective lens 1 collides with the slide glass 13 (see FIG. 1B), the immersion liquid overflows due to the ring-shaped wall formed of the magnetic fluid 19 at the tip. And the contamination of important parts of the optical system can be prevented.

  The above-described embodiment is merely an example, and is not limited to the above-described configuration and shape, and can be appropriately modified and changed within the scope of the present invention.

It is the cross-sectional schematic of the objective lens which concerns on 1st Embodiment, (a) has shown the sample observation state, (b) has each shown the state which the objective lens collided with the sample. It is a schematic block diagram of the microscope which has this objective lens of 1st Embodiment. It is a front-end | tip partial cross-sectional enlarged view in the use condition of the objective lens concerning 2nd Embodiment. It is a schematic block diagram of the microscope carrying the objective lens which concerns on 2nd Embodiment. An example of a cross-sectional shape of a slide glass suitable for the objective lens 30 of the second embodiment is shown, (a) is a state in which a magnetic fluid is dropped and held on the slide glass, and (b) is a state in which the specimen is observed. The state of the magnetic fluid is shown respectively.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,30 Objective lens 3 Lens holder part 5 Housing part 7 Screw part 11 Coil spring 13, 61 Slide glass 15 Concave groove part 17, 37 Permanent magnet 19, 37 Magnetic fluid 20 Inverted microscope 21 Revolver 22 Stage 23 Specimen 24 Illumination optical system 25 Eyepiece Lens 26 Focusing handle 31 Tip lens 62 Recessed part

Claims (6)

A cylindrical housing part, and a cylindrical lens holder part slidably housed in the housing part;
One or more magnets provided on at least one of the inner peripheral surface near the tip of the housing portion and the outer peripheral surface of the lens holder portion facing the inner peripheral surface;
An immersion objective lens, comprising: a magnetic fluid disposed in a gap between the housing portion near the magnet and the lens holder portion.   The immersion objective lens according to claim 1, wherein the magnet is provided over a substantially entire circumference. An objective lens for immersion in a microscope,
A liquid immersion objective lens, wherein a cylindrical magnet is disposed in the vicinity of the tip lens of the objective lens.   The immersion objective lens according to claim 3, wherein the magnet is disposed in a concave groove formed in the vicinity of a tip lens of the objective lens.   4. The immersion objective lens according to claim 3, wherein the magnet is disposed in a lens barrel portion at an outer periphery of a distal end portion of the objective lens.   A microscope comprising the immersion objective lens according to any one of claims 1 to 5.

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