JPH08313785A - Focusing mechanism for microscope - Google Patents

Abstract

PURPOSE: To provide a focusing mechanism which is compact and excellent in spatial property, whose cost is reduced, and which copes with the change of the thickness of a substance to be inspected. CONSTITUTION: Ordinary focusing by coarse and fine adjusting movement is performed by moving a moving base 2 in an optical axis direction through a pinion 4 and a rack 3 by the operation of a coarse adjusting handle 7 or a fine adjusting handle 8 in a state where the fixing of a moving bar 10 by a fixed screw 12 is released and pressing force by a spring 11 is given to a piezoelectric element 9. Focusing by extermely fine movement is performed by extremely finely moving the moving base 2 in the optical axis direction by impressing specified voltage on the piezoelectric element 9 from a state where the moving bar 10 is fixed on a microscope main body 1 by the fixed screw 12 and displacing the piezoelectric element 9 in an elongating and contracting direction.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Normally, focusing in a microscope is
As disclosed in Japanese Examined Patent Publication No. 52-43688, a rack and pinion that interlocks with the rotational movement of a coarse handle or a fine handle moves a sample stage (stage) or a movable stage to which an objective lens is attached in the optical axis direction. It uses a focusing mechanism that allows it to move.

In such a focusing mechanism, the coarse movement handle 1
The moving amount of the moving table per rotation is 5 to 30 mm, and the moving amount of the moving table per one rotation of the fine movement handle is 0.1 to 1 mm.
It has become a degree.

On the other hand, with the recent development of image processing technology, a technology for developing a three-dimensional image by extracting a tomographic image while moving the focus position in steps of 0.01 to 0.05 μm and processing this image is developed. Therefore, the focusing mechanism of the microscope is required to move extremely finely.

However, it is almost difficult to perform such an extremely fine movement by rotating the coarse movement handle and the fine movement handle of the focusing mechanism described above in view of resolution, responsiveness and position reproducibility.

Therefore, as disclosed in Japanese Patent Laid-Open No. 6-109963, in order to secure the precision of movement of a sample stage (stage) or a movable stage to which an objective lens is attached, conventional racks have been used. As described in Japanese Patent Application Laid-Open No. 6-138395, in which a displacement table such as a piezoelectric element is used to directly move the movable table directly without using a pinion, the amount of movement of the movable table is detected by a sensor. Then
It is considered that the output of the sensor is input to the control system of the displacement generating element to precisely control the moving table.

[0007]

However, Japanese Patent Laid-Open No. 6-
The one disclosed in Japanese Patent No. 109963 requires (a) a guide mechanism for guiding the coarse moving table which is moved by the rotation of the focusing handle and a guide mechanism for guiding the fine moving table which is moved by the displacement generating element. , A double guide mechanism for precise guidance is required, the device is large and expensive,
(B) Since the movement displacement of the moving base is not detected, even if the displacement generating element is controlled, there is a possibility that the fine moving base may not move accurately with respect to the coarse moving base due to backlash and deflection of the fine moving mechanism. Yes, it is unknown whether or not the movement displacement of the fine movement table matches the movement target value, and (c) high position reproducibility cannot be obtained due to the hysteresis of the displacement generating element, the backlash and deflection of the fine movement mechanism, etc. There are problems such as.

Further, the device disclosed in Japanese Patent Laid-Open No. 6-138395 requires (a) a guide mechanism for performing precise guidance on each of the coarse movement mechanism section and the fine movement mechanism section, which makes the apparatus large and expensive. (B) When focusing is performed by such a mechanism, it is first necessary to move the stage within the measurement range of the sensor by the coarse movement mechanism. In this case, an electrostatic capacity sensor or a differential transformer type sensor is used as a sensor for detecting the fine movement. The measuring range of the electrostatic capacitance sensor is 20 to 500 μm, and the measuring range of the differential transformer type sensor is 0. It is as small as 0.5 to 2 mm. On the other hand, in the focusing of the microscope, the relative position of the stage and the objective lens varies depending on the thickness of the object to be inspected, so that all focusing can be performed within the measurement range of the sensor used in this mechanism. Can not. In that case, there is a problem that a troublesome operation such as readjustment of the mounting position of the sensor is required.

The present invention has been made in view of the above circumstances, and is small in size, excellent in space and inexpensive in price.
Further, another object of the present invention is to provide a focusing mechanism capable of coping with a change in the thickness of the object to be inspected.

[0010]

According to the first aspect of the present invention,
In a focusing mechanism of a microscope for moving a sample stage or an objective lens of a microscope in an optical axis direction, a microscope main body and the sample stage or the objective lens are provided and supported movably in the optical axis direction with respect to the microscope main body. A moving base, a displacement generating element provided on the moving base and capable of expanding and contracting in the optical axis direction, and a moving member slidably provided on the microscope main body for exerting a pressing force in the optical axis direction on the displacement generating element. And a fixing means capable of fixing the moving member to the microscope body.

According to the second aspect of the invention, the first aspect is
In the description, the moving member has a moving rod slidably provided on the microscope body, and a spring that applies a pressing force in the optical axis direction to the displacement generating element via the moving rod.

[0012]

As a result, according to the first and second aspects of the invention,
Normal focusing by coarse and fine movement is performed by releasing the fixation of the moving member and moving the moving table in the optical axis direction by operating the coarse and fine movement handles. The moving member is fixed to the microscope main body by the fixing means and a predetermined displacement is generated in the displacement generating element, so that the moving table is moved in the optical axis direction.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a vertical sectional view of the same embodiment, and FIG. 2 is a horizontal sectional view thereof. In the figure, reference numeral 1 denotes a microscope main body (fixed table), and a movable table 2 on which a sample table (stage) or an objective lens (neither is shown) is attached to the microscope main body 1 so as to be movable in the optical axis O direction. It is provided.

In this case, the pinion 4 is rotatably provided on the side of the microscope body 1, and the rack 3 meshed with the pinion 4 is fixed on the side of the moving table 2 so that the rotation of the pinion 4 can be changed. Is converted into a linear motion by
Is moved straight in the optical axis O direction.

In this case, a certain amount of backlash is usually provided between the rack 3 and the pinion 4 in order to ensure the precision of movement by a fine movement handle 8 which will be described later. The weights of the movable table 2 and the stage or the objective lens attached to the movable table 2 are acted in the vertical direction along the optical axis O between the pinions 4 and are engaged with each other while being pressed to one side.

Further, a pair of roller races 5 is provided between the microscope body 1 and the movable table 2, and these roller races 5 guide the movement of the movable table 2 in the optical axis O direction via the rollers 6. I am trying.

Reference numeral 7 is a coarse movement handle, and 8 is a fine movement handle. These coarse movement handle 7 and fine movement handle 8 are connected to a coarse and fine movement mechanism portion 13 provided penetrating the microscope main body 1, and the coarse and fine movement mechanism portion 13 controls the rotation of the pinion 4. . In this case, the details of the coarse and fine movement mechanism 13 operated by the coarse and fine handles 7 and 8 are disclosed in Japanese Patent Publication No. 52-43688 and will not be described here.

On the other hand, a piezoelectric element 9 as a displacement generating element is fixed to the movable table 2 in a direction along the optical axis O, and an end face of this piezoelectric element 9 is slidably attached to the microscope body 1 side. It is in contact with the moving rod 10.

In this case, the piezoelectric element 9 can be expanded and contracted in the optical axis O direction by applying a predetermined voltage by a voltage application means (not shown). In addition, the moving rod 10
Is adapted to constantly press the piezoelectric element 9 by the spring 11. In addition, 12 is a fixing screw, and the moving rod 10
Is fixed to the microscope body 1.

In this case, if the piezoelectric element 9 is in the most contracted state when the piezoelectric element 9 is not operated, when the voltage is applied to the piezoelectric element 9, the moving base 2 moves upward. Further, at this time, the movement stroke required for the ultrafine movement by the piezoelectric element 9 is 100 to 200 μm at the most, and it can be absorbed by the play between the gears described above, so that it is affected by the meshing of the rack 3 and the pinion 4. Instead, the movable table 2 can be moved extremely finely and precisely by the expansion and contraction of the piezoelectric element 9.

However, in such a structure, first, when the normal focusing is performed by the coarse and fine movement, the fixing screw 12 is released, and the coarse movement handle 7 or the fine movement handle 8 is rotated to rotate the pinion. 4 is rotated to move the moving table 2 via the rack 3. Then, the movable table 2 is guided by the roller race 5 and the roller 6 and precisely moves in the optical axis direction, so that the sample on the sample table (not shown) attached to the movable table 2 can be focused.

In this case, since the spring 11 acts as a counter spring for the movable table 2, the coarse operation handle 7 and the fine operation handle 8 can be smoothly rotated. Further, in this state, since the fixing screw 12 is released, the tip of the moving rod 10 moves over the entire coarse and fine movement range while being pressed by the piezoelectric element 9 by the spring 11.

Next, in the case of performing focusing by ultrafine movement, first, as described above, the coarse moving handle 7 or the fine moving handle 8 is used to focus the sample on the sample table (not shown) mounted on the moving table 2. After that, the movable rod 10 is fixed to the microscope main body 1 with the fixing screw 12.

Then, from this state, a predetermined voltage is applied to the piezoelectric element 9 by a voltage applying means (not shown) so that the piezoelectric element 9 is expanded and contracted. In this case, since the movable rod 10 is in contact with the piezoelectric element 9 while being integrally fixed to the microscope main body 1 by the fixing screw 12, the expansion / contraction amount of the piezoelectric element 9 becomes the movement amount with respect to the microscope main body 1. The table 2 is guided along the roller races 5 and 6 and is moved by the same amount as the expansion and contraction amount of the compression element 9, so that it is possible to perform focusing by ultrafine movement.

Therefore, according to such an embodiment, in the normal focusing by the coarse and fine movement, the fixation of the moving rod 10 by the fixing screw 12 is released and the pressing force by the spring 11 is applied to the piezoelectric element 9. The movement table 2 is moved in the optical axis direction through the pinion 4 and the rack 3 by operating the coarse movement handle 7 or the fine movement handle 8, and the fine rod movement is used to adjust the movement rod 10 with the fixing screw 12. By applying a predetermined voltage to the piezoelectric element 9 in a state of being fixed to the microscope main body 1 to generate a displacement in the expansion / contraction direction of the piezoelectric element 9, the movable table 2 is moved extremely finely in the optical axis direction. ing.

As a result, the movable table 2 can be guided in the optical axis direction by the common guide mechanism in both coarse and fine movements, so that it is small, has excellent space, and is inexpensive. A focusing mechanism can be obtained.

Further, since the spring 11 acts as a counter spring when operating the coarse and fine movement handles 7 and 8, there is also an effect that the rotations of the coarse and fine movement handles 7 and 8 can be lightened.

Further, since the moving rod 10 and the piezoelectric element 9 are always moved in contact with each other, even if the thickness of the sample is changed, if the moving rod 10 is fixed by the fixing screw 12, the piezoelectric material is piezoelectric. Ultra-fine movement by the element 9 is possible,
It is possible to perform highly accurate focusing that is not affected by changes in the sample thickness.

In the above-described embodiment, the fixing screw 12 is used as the fixing means for the moving rod 10, but instead of the fixing screw 12, an electromagnetic solenoid or an electromagnetic brake may be used to improve the operability. be able to.

Further, a position detecting sensor for detecting the relative distance to the moving rod 10 is provided on the side of the moving base 2, and the relative distance detected by this position detecting sensor is fed back to the voltage applying means (not shown) of the piezoelectric element 9. If the configuration is such that closed loop control is performed, more accurate position control of the moving base 2 becomes possible.

Although the above description has been given based on the embodiments, the present invention includes the following inventions. (1) In a focusing mechanism of a microscope for moving a sample stage or an objective lens of a microscope in an optical axis direction, a microscope main body and the sample stage or the objective lens are provided and movable in the optical axis direction with respect to the microscope main body. A supported moving table, a displacement generating element provided on the moving table and capable of expanding and contracting in the optical axis direction, and a displacement generating element slidably provided on the microscope main body and exerting a pressing force in the optical axis direction on the displacement generating element. A focusing mechanism for a microscope, comprising: a moving member for moving the moving member; and fixing means for fixing the moving member to the main body of the microscope.

In this way, the normal focusing by the coarse and fine movement movement is performed by releasing the fixing of the moving member and moving the moving base in the optical axis direction by operating the coarse movement handle and the fine movement handle. , Focusing by the ultrafine movement, by fixing the moving member to the microscope main body by the fixing means and causing a predetermined displacement in the displacement generating element, the moving table is moved in the optical axis direction. A common guide mechanism can be used for both coarse and fine movements of the moving table, and it is compact and space-saving, and can be manufactured at low cost. It is possible to respond to changes in.

(2) In the focusing mechanism described in (1), the moving member includes a moving rod slidably provided on the microscope main body, and the displacement generating element in the optical axis direction via the moving rod. It has a spring that exerts a pressing force. Even in this case, the same effect as (1) can be obtained.

[0034]

As described above, according to the present invention, a common guide mechanism can be used for both coarse and fine focus movements of the moving table and ultrafine focus adjustment, and it is small and excellent in space. In addition, it is possible to provide a focusing mechanism which can be made inexpensive and can cope with a change in the thickness of the object to be inspected.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a schematic configuration of an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a schematic configuration of one embodiment.

[Explanation of symbols]

 1 ... Microscope main body (fixed base), 2 ... Moving base, 3 ... Rack, 4 ... Pinion, 5 ... Corolace, 6 ... Roller, 7 ... Coarse movement handle, 8 ... Fine movement handle, 9 ... Piezoelectric element, 10 ... Moving rod , 11 ... Spring, 12 ... Fixing screw, 13 ... Coarse / fine movement mechanism part.

Claims (2)

[Claims] 1. A focusing mechanism of a microscope for moving a sample stage or an objective lens of a microscope in an optical axis direction, wherein a microscope main body and the sample stage or the objective lens are provided and moved in the optical axis direction with respect to the microscope main body. A movable table supported freely, a displacement generating element provided on the movable table and capable of expanding and contracting in the optical axis direction, and a pressing force in the optical axis direction applied to the displacement generating element slidably provided on the microscope main body. A focusing mechanism for a microscope, comprising: a moving member that acts on the moving member; and a fixing unit that can fix the moving member to the microscope body. 2. The moving member has a moving rod slidably provided on the microscope main body, and a spring for exerting a pressing force in the optical axis direction on the displacement generating element via the moving rod. The focusing mechanism of the microscope according to claim 1.