JPH04366539A - Electron microscope objective diaphragm drive device - Google Patents

Abstract

PURPOSE:To make the moving direction of an objective diaphragm coincide with the moving direction of a mouse on a screen regardless of an image observation mode or a diffraction pattern observation mode. CONSTITUTION:When a diffraction pattern observation mode is selected, a control device 3 detects the movement of a mouse 4, and shows the movement direction and the movement amount of an objective diaphragm 1 to an objective diaphragm drive portion 2. Then, the shown movement direction is the movement direction with the movement direction of the mouse 4. In the case of an image observation mode, while the control device 3 detects the movement of the mouse 4 and shows the movement direction and the movement amount of the objective diaphragm 1 to the objective diaphragm drive portion 2, the control device 3 judges the excitation of a condenser lens and an objective lens so as to reverse an X direction and a Y direction by 180 deg. respectively on the movement direction as a need arises.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is a transmission electron microscope (T
This invention relates to a driving device for an objective aperture in an EM.

0002

[Prior Art] A TEM is equipped with an image observation mode for observing an enlarged image of a sample (hereinafter simply referred to as an image) and a diffraction pattern observation mode for observing a diffraction pattern of the sample. It is possible to observe dark-field images. When observing a bright-field image or a dark-field image, first select a desired spot from the diffraction pattern observed on the screen in the diffraction pattern observation mode using the objective aperture, and then change to the image observation mode. will be held. Conventionally, to adjust the position of the objective diaphragm when selecting a desired spot, the objective diaphragm is moved in the X and Y directions in a plane perpendicular to the optical axis by operating the objective diaphragm position adjustment knob while observing the screen. However, in recent years, it has been proposed to use a pointing device such as a joystick or a mouse. An example of its configuration is shown in FIG.

In FIG. 3, an objective diaphragm 1 is formed with a plurality of apertures having different diameters, and is moved by an objective diaphragm driving section 2 in the X and Y directions in the figure. A control device 3 consisting of a microprocessor or the like detects the movement of a mouse 4 as a pointing device, and instructs an objective diaphragm drive unit 2 consisting of an appropriate actuator, motor, motor drive circuit, etc. to move the objective diaphragm 1 in the moving direction and movement. Indicate the amount. This eliminates the need for cumbersome picking operations like in the past.
The two-dimensional movement of the objective aperture can be easily controlled by operating a pointing device such as a mouse while observing the screen. Note that in FIG. 3, the Z direction indicates the optical axis direction. Furthermore, the control device 3 may be a device that controls only the movement of the objective aperture, or may also serve as a control device that performs other controls of the TEM.

0004

By the way, as mentioned above, the objective aperture is used to select a desired spot in the diffraction pattern observation mode.
In the case where the position of the objective diaphragm is adjusted by a pointing device, the movement direction of the shadow formed by the objective diaphragm on the screen is set to match the movement of the pointing device in the diffraction pattern observation mode.

However, even after selecting a desired spot with the objective diaphragm in the diffraction pattern observation mode and switching to the image observation mode, there are cases where it is desired to move the objective diaphragm. Depending on the excitation conditions of the lens, the number of times the direction of the image and the diffraction pattern are reversed may differ by only one, and in that case, the positional relationship between the image and the diffraction pattern observed on the screen will be
and the Y direction are reversed by 180 degrees. Furthermore, depending on the positional relationship between the diffraction pattern and the objective aperture, the moving direction of the shadow of the objective aperture on the screen and the moving direction of the aperture may be reversed by 180°. Therefore, if the moving direction of the objective aperture on the screen is set to match the movement of the pointing device in the diffraction pattern observation mode, if the pointing device is operated in the image observation mode, the objective aperture on the screen will move in the same direction as the pointing device. The movement of the shadow caused by the movement of the pointing device may be completely opposite to the movement of the pointing device.
This caused great confusion for operators.

On the other hand, by appropriately setting the excitation conditions of the lenses disposed after the objective aperture, either the image projected on the screen or the diffraction pattern can be adjusted by 180° in the X and Y directions. Although it is not impossible to rotate the lens, it is not preferable because it causes disadvantages such as increased aberrations.

[0007] The present invention solves the above problem, and in both the image observation mode and the diffraction pattern observation mode, the moving direction of the shadow formed by the objective aperture on the screen coincides with the movement of the pointing device. It is an object of the present invention to provide a matching objective aperture driving device for an electron microscope.

[0008]

[Means for Solving the Problems] In order to achieve the above object, an objective diaphragm driving device for an electron microscope according to the present invention provides an objective diaphragm driving means for moving an objective diaphragm in response to movement of a pointing device. In the diaphragm driving device, the objective diaphragm driving means moves the objective diaphragm corresponding to the pointing device in opposite directions in an image observation mode and a diffraction image observation mode.

[0009]

[Operation] When the diffraction pattern observation mode is selected, the control device 3 detects the movement of the mouse 4 as a pointing device, and controls the objective diaphragm 1 with respect to the objective diaphragm drive unit 2 as the objective diaphragm drive means. The direction and amount of movement are instructed, and the direction of movement specified at this time is the direction in which the direction of movement of the shadow formed by the objective aperture 1 on the screen matches the direction of movement of the mouse 4. In the case of the image observation mode, the control device 3 detects the movement of the mouse 4 and instructs the objective aperture drive unit 2 to move the objective aperture 1 in the direction and amount of movement. In mode, it rotates by 180 degrees in each of the X and Y directions.

0010

Embodiments Hereinafter, embodiments will be described with reference to the drawings. FIG. 1 is a diagram showing the configuration of an embodiment of an objective aperture drive device for an electron microscope according to the present invention, and 5 in the figure indicates a mode switch. In FIG. 1, the same or equivalent parts as in FIG. 3 are given the same reference numerals. In addition, the TEM
In this case, the positional relationship between the image observed on the screen and the diffraction pattern is 180° from each other in the X and Y directions.
It is assumed that the image is set to be reversed.

The mode switch 5 is a switch for selecting between an image observation mode and a diffraction pattern observation mode, and when the mode switch 5 selects the diffraction pattern observation mode, the control device 3 operates as in the conventional case. mouse 4
Detects the movement of the objective diaphragm 1 to the objective diaphragm drive unit 2.
Instruct the direction and amount of movement. The moving direction instructed at this time is the direction in which the moving direction of the shadow by the objective aperture 1 on the screen matches the moving direction of the mouse 4. As a result, the direction of movement of the objective aperture on the screen is set by the mouse 4.
This corresponds to the movement of

When the image observation mode is selected by the mode switch 5, the control device 3 detects the movement of the mouse 4 and instructs the objective diaphragm drive unit 2 to move the objective diaphragm 1 in the direction and amount of movement. When moving in the X and Y directions, the following condenser lenses,
It determines the excitation of the objective lens and rotates it 180 degrees as necessary. As a result, even in the image observation mode, the direction of movement of the objective aperture on the screen matches the movement of the mouse 4.

Further, the control device 3 takes in the excitation current of the condenser lens and/or the objective lens, and based on the excitation conditions, the position of the back focal plane where the diffraction pattern is imaged is on the electron gun side of the objective aperture 1. It is determined whether the moving direction of the mouse 4 is the same as the moving direction of the mouse 4 or whether it is reversed. That is, in the image observation mode, FIG.
If the back focal plane is formed at the position of objective aperture 1 and on the screen side (lower side in Fig. 2) than objective aperture 1, as shown by A in Fig. It is possible to match the moving direction of the shadow created by the objective aperture with the moving direction of the mouse 4, but if the back focal plane is formed closer to the electron gun than the objective aperture 1, as shown by B in FIG. Since the direction in which the objective aperture 1 blocks the electron beam is reversed, when the control device 3 performs the above processing, the moving direction of the shadow created by the objective aperture 1 on the screen is different from the moving direction of the mouse 4. It will be the opposite. Note that in FIG. 2, EB indicates an electron beam. However, since the position where the back focal plane is formed can be determined by the excitation conditions of the condenser lens and/or objective lens, the position of the back focal plane can be determined by taking in the excitation current of these lenses, and the position of the back focal plane can be determined by is determined to be closer to the electron gun than the objective diaphragm 1, as shown in B in FIG. When instructing the movement direction and movement amount, the movement direction is 180% in each of the X and Y directions.
°Perform the rotation process. Regarding the acquisition of the excitation current, if the control device 3 controls only the movement of the objective diaphragm 1, the excitation current may be input from the control device that controls the excitation current of the lens; If the excitation current also controls the excitation current of the lens, the currently supplied excitation current value may be referred to.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment and can be modified in various ways. Any device that can match the direction of movement of the objective diaphragm on the screen with the direction of movement of the pointing device may be used.

[0015]

As is clear from the above description, according to the present invention, the direction of movement of the shadow of the objective diaphragm on the screen can always be made to coincide with the direction of movement of the pointing device, so that image observation is improved. The movement of the objective diaphragm can be easily and comfortably controlled regardless of the mode or diffraction pattern observation mode.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of an embodiment of the present invention.

FIG. 2 is a diagram for explaining control of the movement direction of the objective diaphragm according to the position of the back focal plane.

FIG. 3 is a diagram showing a configuration example of an objective aperture position adjustment device using a pointing device.

[Explanation of symbols]

1...Objective aperture, 2...Objective aperture drive unit, 3...Control device, 4
...mouse, 5...mode switch.

Claims (1)

[Claims] 1. An objective diaphragm driving device comprising an objective diaphragm driving means for moving an objective diaphragm in response to movement of a pointing device, wherein the objective diaphragm driving means moves the pointing diaphragm in an image observation mode and a diffraction image observation mode. An objective aperture drive device for an electron microscope, characterized in that the movement direction of an objective aperture corresponding to a device is opposite.