JPH06109963A - Focusing mechanism for microscope - Google Patents

Abstract

PURPOSE:To realize high rigidity by simple structure and to perform focusing with higher accuracy. CONSTITUTION:This mechanism is equipped with a coarse adjustment board 6 which is supported so as to freely move in an optical axis direction in a microscope main body 4, a coarse adjustment mechanism 8 for coarsely adjusting the board 6, a fine adjustment board 13 which is supported so as to freely move in the optical axis direction on the board 6 and to which a sample plate, or an objective lens 1 is attached, and a fine adjustment mechanism 18 for finely adjusting the board 13 by a displacement causing element 15 fixed on the board 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a focus adjusting mechanism for adjusting the focus by moving a sample stage or an objective lens of a microscope in the optical axis direction.

[0002]

2. Description of the Related Art Normally, focusing in a microscope is
This is done by rotating the focusing handle to move the sample to the focal position of the objective lens. In this case, by rotating the focusing handle, the stage on which the sample is placed is moved up and down, or the revolver with the objective lens fixed is moved up and down.

Generally, the vertical movement of the stage or the vertical movement of the revolver is performed by a rack and pinion which is interlocked with the rotational movement of the focusing handle.
By rotating the focusing handle, the stage or the revolver can be moved roughly or finely in the optical axis direction.

Further, for example, in Japanese Patent Laid-Open No. 61-270715, as a means for moving the stage up and down electrically, an adapter is attached to a focusing handle portion and a focusing handle is directly rotated by a stepping motor or the like. Is disclosed.

[0005]

As described above, since the vertical movement of the stage or the revolver is carried out by the rack and pinion that is interlocked with the rotational movement of the focusing handle, there is backlash. become. For this reason, in the case of a configuration in which the guide of the microscope focusing unit is used as a guide for precision fine movement, that is, in a configuration in which the stage or revolver is moved up and down by precisely rotating the focusing handle, it is assumed that the focusing handle is rotated precisely. Also,
The actual movement of the stage or revolver lacks precision due to the backlash of the rack and pinion.

Further, in the structure in which the microscopic movement axis of the microscope is directly rotated slightly, since a mechanism for microscopic rotation is provided outside the microscope main body, it is difficult to make the rotation center of the mechanism coincide with the rotation center of the microscopic movement axis of the microscope.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a focus adjusting mechanism of a microscope which can realize high rigidity with a simple structure and enables highly accurate focus adjustment. And

[0008]

In order to achieve the above object, a focus adjusting mechanism of a microscope according to the present invention comprises a coarse moving table supported by a microscope main body so as to be movable in an optical axis direction, and the coarse moving table. A coarse movement mechanism for coarse movement, a fine movement table movably supported on the coarse movement table in the optical axis direction to which the sample stage or the objective lens is attached, and a displacement generation element fixed to the coarse movement stage. And a fine movement mechanism for finely moving the fine movement table.

[0009]

In the focus adjusting mechanism of the microscope according to the present invention, the driving force is transmitted to the coarse moving table via the coarse moving mechanism, and the coarse moving table is guided by the microscope main body while supporting the sample table or the objective lens. Move along the optical axis. Further, the displacement generated in the displacement generating element is transmitted to the fine movement table via the fine movement mechanism, and the fine movement table is supported by the coarse movement table and finely moves in the optical axis direction.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

An embodiment in which the focus adjusting mechanism according to the present invention is applied to an inverted microscope will be described as a first embodiment. 1 to 3 are respectively a front view, a top view, and a side view of an inverted microscope equipped with the focus adjusting mechanism according to the first embodiment.

In the inverted microscope shown in the same figure, an observation image is taken in from the objective lens 1, reflected by a reflection prism 2 arranged vertically downward from the objective lens 1 and guided to an eyepiece lens so that the observation image can be magnified and observed. An optical system is formed in.

The microscope main body 4 has two side walls 4a and 4b facing each other, and a pair of linear bearings 5a and 5b are arranged in the vertical direction at opposite positions on the inner surfaces of the side walls 4a and 4b. ing. The coarse moving table 6 is sandwiched between the pair of linear bearings 5a and 5b.
Can be moved in the vertical direction, which is the optical axis direction, by using the linear bearings 5a and 5b as guides.

A focusing axis 7 penetrates through the two side walls 4a and 4b of the microscope body 4 in the horizontal direction orthogonal to the optical axis direction, and the focusing axis 7 is focused on a portion of the focusing axis 7 which is outside the microscope body. A quasi-knob 8 is attached. A gear portion 9 is formed on an outer peripheral surface of a part of the focusing shaft 7, and the gear portion 9 is a gear group 10
Is mechanically coupled to the rack 11 formed on the back surface of the coarse moving table 6 via.

The coarse moving table 6 has a pair of linear bearings 12a and 12b formed in the vertical direction. Both sides of the fine movement table 13 are slidably held by the pair of linear bearings 12a and 12b. Microtremor 1
A slanted collar portion 13a is formed at the upper end portion of 3, and a revolver 14 is rotatably attached to the upper surface of the collar portion 13a. The objective lens 1 is attached to the revolver 14.

A long piezoelectric element 15 is fixedly mounted on the fine moving table mounting surface of the coarse moving table 6 with its longitudinal direction and expansion / contraction direction oriented in the vertical direction. The piezoelectric element 15 has a projecting portion 15a protruding from the lower end portion of the element which is aligned at substantially the same position as the lower end surface of the fine movement table 13. A protrusion 13b similar to the protrusion 15a is provided at a predetermined distance from the protrusion 15a at the lower end of the fine movement table. And the protrusion 13
A shaft 16 is planted on the coarse moving table 6 at a substantially intermediate position between b and 15a with the shaft 16 protruding in the horizontal direction. A lever 18 is rotatably attached to the shaft 16 via a bearing 17. At both ends of the upper surface of the lever 18, hard balls 19a, 1
9b is embedded, and the tips of the protrusions 15a and 13b are in contact with the hard spheres 19a and 19b. A voltage can be applied to the piezoelectric element 15 from the outside by a voltage applying unit (not shown) to arbitrarily expand and contract.

A spring base 21 is fixed to the fine motion base mounting surface of the coarse motion base 6. The spring base 21 has a pair of screw holes formed in the center thereof. A male screw portion 23, which is integrally formed concentrically with the spring shaft 22, is screwed into each of the screw holes to fix the spring shaft 22 to the spring base 21. A compression spring 25 is loosely inserted in each spring shaft 22. On the other hand, the tip end of each spring shaft is inserted into the spring bearing 25 fixed to the fine movement table 13, and the restoring force of the compression spring 24 causes the spring bearing 2 to move.
It is configured to be transmitted to the fine movement table 13 via the control unit 4.

In this embodiment constructed as described above, when the focusing knob 8 is rotated, its rotational force is transmitted to the coarse moving table 6 via the gear group 10 and the rack 11, and the coarse moving table 6 is moved. It is guided by the linear bearings 5a and 5b to roughly move in the vertical direction. The fine movement table 13 to which the objective lens 1 is attached via the revolver 14 is held from below by the coarse movement table 6 via the piezoelectric element 15 and the lever 18, so that the coarse movement table 6
It becomes a unit to move roughly vertically.

When the voltage applied to the piezoelectric element 15 from a voltage applying means (not shown) is adjusted, the piezoelectric element 15 expands and contracts according to the applied voltage. For example, when a voltage is applied in a direction in which the piezoelectric element 15 extends, the hard sphere 19a of the lever 18 is pushed by the protrusion 15a of the piezoelectric element 15 by a distance corresponding to the amount of displacement. When the hard sphere 19a is pushed downward, the lever 18 rotates counterclockwise around the shaft 16, and the hard sphere 19b relatively located at the other end of the lever 18 is pushed up. Since the lower end of the fine movement table 13 is in contact with the rigid ball 19b via the protrusion 13b, the fine movement table 13 receives a force pushed upward through the rigid ball 19b and is guided by the linear bearings 12a and 12b to move upward. Move slightly to.

In addition to its own weight, the fine movement table 13 exerts almost no force for restricting its upward movement (sliding resistance by the linear bearings 12a, 12b). Moreover, only the revolver 14, the objective lens 1 and the spring receiver 24 are attached to the fine movement table 13, and the fine movement mechanism including the piezoelectric element 15, the lever 18 and the like is attached to the coarse movement table 6 side. Therefore, the weight of the fine movement table 13 is reduced.

Therefore, since the force received by the fine movement table 13 from the lever 18 is efficiently converted into the movement amount, it becomes possible to move the fine movement table 13 with a small force, and the focus adjustment with high precision becomes possible. .

Further, when the weight of the fine movement table 13 is reduced, the natural frequency of the device is increased and the vibration of the entire device can be suppressed, and the piezoelectric element 15 to be used has dimensional and weight restrictions. Has the advantage of being less.

Further, since the fine movement table 13 receives the pressing force of the compression spring 25 on the lower surface of the spring receiver 24, the fine movement table 13 has the following characteristics:
The contact pressure generated between 9b and between 15a and 19a is
It is reduced by the pressing force of the compression spring 25. Therefore,
In addition to reducing the weight of the fine movement table 13, the compression spring 2
Since the reducing function of 5 works, the contact pressure is reduced,
Therefore, it is possible to prevent the positioning accuracy of the fine movement table 13 from being deteriorated due to the stick-slip generated at the contact portion. Here, a mechanism of deterioration of positioning accuracy due to stick-slip will be described.

FIGS. 9A to 9C are explanatory views of stick-slip. In the figure, (a) of the figure shows the state in which the piezoelectric element 15 is contracted, and (b) and (c) of the figure are in the extended state. If there is no friction between 15a and 19a, the state of (c) is immediately reached when 15 is extended by ΔL from the state of (a). However, actually 15a and 1
As a result of the friction with 9a, as shown in (b), 15a and 19a
15 is stretched while sticking, and as a result, 15a is deformed to the right. Eventually, when the elasticity of 15a overcomes the friction, the state of (c) is obtained. At this time, a slip of Δx occurs between 15a and 19a. This is stick-slip. Stick-slip, of course, 13b and 1
Between 9b and 9b. Since the stick-slip operation is intermittent, the smooth movement of 18 or 13 is impaired when this occurs. As a result, the linearity of the movement of the fine moving body 13 and the deterioration of the positioning accuracy will be caused. Further, according to the present embodiment, since the coarse moving table 6 and the fine moving table 13 each have a single structure, the rigidity of the entire apparatus can be increased. Next, an example will be described as a second embodiment, which has the basic structure of the first embodiment described above and only the fine movement mechanism portion is modified. The second embodiment will be described with reference to FIG. The same parts as those in the first embodiment are designated by the same reference numerals to avoid duplication of description.

In this embodiment, the piezoelectric element 15 'is attached to the coarse moving table 6 with the expansion / contraction direction facing upward and downward, and the projection 26 at the tip of the piezoelectric element 15' is directly attached to the facing portion of the fine moving table 13 from below. It is configured to abut. It should be noted that the fine movement table 13
A hard sphere 27 is embedded in the portion that comes into contact with the piezoelectric element 15 ′. Therefore, in this embodiment, the power transmission mechanism such as the lever is omitted. According to the present embodiment as described above, the factors of positioning error are smaller than those in the first embodiment,
Higher positioning accuracy can be achieved.

Next, an example will be described as a third embodiment, which has the basic structure of the above-described first embodiment and has a modified structure for mounting the lever and a structure for reducing the weight of the fine movement table. A third embodiment will be described with reference to FIG. The same parts as those in the first embodiment are designated by the same reference numerals to avoid duplication of description.

In this embodiment, a pair of mounting bases 31a, 31 are provided on the mounting surface of the fine moving base 6 ', which are spaced apart from the width of the fine moving base.
b is provided. The two mounts 31a and 31b are
It has a rectangular shape with a predetermined thickness, and is arranged at the same height with the short sides of the two parallel to each other.

On the other hand, the fine movement base 13 'is a pair of mounting bases 31.
It is arranged between a and 31b, and a region of the front side wall of the fine movement table 13 'that faces the mounting bases 31a and 31b is shaved so as to make a gap between the upper and lower end faces of the mounting bases 31a and 31b. The parts 32a and 32b are respectively formed. One end of the leaf spring 33a is fixed to the upper end surface of the mounting base 31a with a screw, and the other end of the same leaf spring 33a is fixed to the gap 32a of the fine movement base 13 'with a screw from below. Has been done. Similarly, the upper end surface of the mounting base 31b and the disconnection portion 3
A leaf spring 33b is hung between the mounting base 31a,
The leaf spring 34 is also provided between the lower end surface of 31b and the disconnection portion 32b.
a and 34b are hung. The lever 18 'is rotatably supported by a shaft 16' mounted on the coarse moving table 6'via a leaf spring 35 arranged radially.

In the present embodiment constructed as described above, the fine movement table 13 'is not supported by the linear bearings as in the first and second embodiments, but the parallel leaf springs 33a,
It is supported by the coarse moving table 6'through 33b, 34a and 34b. Therefore, since the rolling bearing is not used in the fine movement mechanism, it is possible to prevent a positioning error due to the viscosity of the lubricating oil, which is unavoidable when the rolling bearing is used, in particular, the occurrence of hysteresis.

Since the parallel plate springs 33a, 33b, 34a, 34b supporting the fine movement table 13 'have elasticity,
It also has the effect of operating similarly to the compression springs used in the first and second embodiments.

By the way, in each of the above-described embodiments, the case where the focus adjusting mechanism of the present invention is moved on the objective lens side has been described. Next, a focus adjusting mechanism for moving the sample table will be described as a fourth embodiment.

6 to 8 are a side view, a front view, and a top view of the main part of the focus adjusting mechanism of the fourth embodiment. The present embodiment is a focus adjusting mechanism for vertically moving a sample table provided in an upright microscope or an inverted microscope.

Two opposing side walls 40 of the microscope body 40
A pair of linear bearings 41a and 41b are arranged in the vertical direction on a and 40b, and both sides of the coarse moving table 42 are slidably held between the linear bearings 41a and 41b.

The side walls 40a and 40b of the microscope body 40 are also provided.
A focusing axis 43 is inserted between the focusing axes 43, and focusing knobs 44 are attached to both ends of the focusing axis 43. A gear 46 is axially supported by a holding member 45 fixed to the microscope main body 40, and a gear portion formed on a part of the focusing shaft 43 is formed on the back surface of the coarse movement table 42 via the gear 46. It is connected to the rack 47.

The coarse moving table 42 is formed in a U-shaped cross section with the surface facing the rack forming surface opening outward, and the linear bearings 48 are provided on the two sides of the opening extending vertically.
a and 48b are provided. A fine movement table 49 is slidably held between the pair of linear bearings 48a and 48b. The sample table 50 is attached to the upper surface of the fine movement table 49.

Further, a piezoelectric element 51 is attached to the side surface of the coarse moving table 42 facing the back surface of the fine moving table with the expansion / contraction direction oriented horizontally. A protrusion 51 a is formed on the tip of the piezoelectric element 51. A shaft 52 is planted on the side surface of the coarse motion table a predetermined distance below the protrusion 51a, and a bent portion of an L-shaped lever 53 is rotatably attached to the shaft 52 via a bearing 54. ing. One side of the lever 53 is in contact with the protrusion 51a. On the other hand, a hard sphere 55 is embedded on the other side of the lever 53, and engages with an engaging plate 56 provided on the back surface of the fine movement table 49.

A spring base 57 is mounted on the side surface of the coarse motion base to which the piezoelectric element 51 is mounted, and a male screw 58 is screwed into a screw hole formed in the spring base 57. . A hole is formed in the upper end surface of the male screw 58, and the base end portion of the compression spring 59 is inserted and fixed in the hole. Further, a spring receiver 60 attached to the lower surface of the fine movement table 49.
Extends above the spring base 57, and the lower surface of the spring receiver 60 is pressed by the compression spring 59.

In the present embodiment configured as described above, when the sample table 50 is roughly moved and finely moved, the same operation as that of the first embodiment and the same effect as that of the first embodiment are obtained. You can

[0039]

As described above in detail, according to the present invention, it is possible to provide a focus adjusting mechanism for a microscope which can realize high rigidity with a simple structure and which enables highly accurate focus adjustment.

[Brief description of drawings]

FIG. 1 is a front sectional view of a focus adjusting mechanism according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional top view of the focus adjustment mechanism shown in FIG.

FIG. 3 is a side sectional view of the focus adjustment mechanism shown in FIG.

FIG. 4 is a front sectional view of a focus adjusting mechanism according to a second embodiment of the present invention.

FIG. 5 is a front sectional view of a focus adjusting mechanism according to a third embodiment of the present invention.

FIG. 6 is a side sectional view of a focus adjusting mechanism according to a fourth embodiment of the present invention.

7 is a front view of the focus adjustment mechanism shown in FIG.

8 is a top cross-sectional view of the focus adjustment mechanism shown in FIG.

FIG. 9 is a diagram for explaining the principle of stick-slip generation.

[Explanation of symbols]

1 ... Objective lens, 4, 40 ... Microscope main body, 6, 6 ', 4
2 ... Coarse movement table, 7, 43 ... Focusing axis, 8, 44 ... Focusing handle, 13, 13 ', 49 ... Fine movement table, 14 ... Revolver, 1
5 ... Piezoelectric element, 18, 18 ', 53 ... Lever, sample table 5
0.

Claims (2)

[Claims] 1. In a focus adjusting mechanism for moving a sample stage or an objective lens of a microscope in an optical axis direction, a coarse moving stage supported by a microscope main body so as to be movable in the optical axis direction, and coarsely moving the coarse moving stage. A coarse movement mechanism, a fine movement table movably supported on the coarse movement table in the optical axis direction to which the sample stage or the objective lens is attached, and a fine movement by a displacement generating element fixed to the coarse movement stage. A focus adjusting mechanism for a microscope, comprising a fine moving mechanism for finely moving a table. 2. A focus adjusting mechanism for a microscope according to claim 1, further comprising a pressing member which is fixed to the coarse moving table and applies an upward pressing force to the fine moving table.