JP2009295429A - Electron microscope with camera for image observation - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electron microscope with a camera for image observation, capable of rotating an observation image to an optional angle without changing the visual field. <P>SOLUTION: The electron microscope comprises a camera 45 for electron microscopic image observation for photographing and displaying an image on a fluorescent plate to which an electron microscopic image is projected; a rotating means 51 which rotates the camera 45 around the lens optical axis of the camera 45; a rotary drive means 52 for driving the rotating means 51; and a control means 48 which gives a drive according to the magnitude of rotating angle and rotating direction of the camera 45 to the rotary drive means 52 to control the rotation of the camera. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electron microscope provided with an image observation camera, and more particularly to a rotation mechanism of an electron microscope image observation camera that allows a sample image to be rotated at an arbitrary angle.

(Conventional example 1)
FIG. 8 is a diagram showing a configuration example of a conventional apparatus. In the figure, reference numeral 50 denotes an electron microscope mirror. The mirror 50 includes a sample 41, a fluorescent plate 42 that visualizes a sample image, a mirror 43 that reflects an optical signal from the fluorescent plate 42 in a 90-degree direction, and a glass 44 formed in the mirror 50. It is. A lens 46 receives and reflects the reflected signal from the mirror 43 through the glass 44.

  Reference numeral 45 denotes a camera that captures an image signal focused by the lens 46. As the camera 45, for example, a CCD camera is used. Reference numeral 47 denotes a member for fixing the camera 45 having one end attached to the wall surface of the mirror body 50. Reference numeral 48 denotes a control device such as a personal computer (PC) that takes in the captured image of the camera 45 and processes the image and receives each command to control the overall operation of the device shown in FIG.

  In the apparatus configured as described above, the sample image reaches the fluorescent screen 42 and is converted into a video signal. The image signal converted into the video signal is bent 90 degrees by the mirror 43 and enters the camera 45 through the lens 46. An image signal photographed by the camera 45 is displayed on a display in the control device 48.

As a conventional apparatus of this type, there is known an apparatus in which a camera that is rotatable along an optical axis is provided outside a projection chamber in order to view an optical sample image obtained in the projection chamber (for example, a patent). Reference 1).
(Conventional example 2)
By the way, in an electron microscope, in order to obtain a desired magnification, a multi-stage imaging system electromagnetic lens is used. Since an electromagnetic lens has a small opening angle, it can be approximated as an optical thin lens. Therefore, Newton's lens formula 1 / f = (1 / x) + (1 / z)
Can be applied. Here, it is assumed that the focal length of the lens is f, the object plane distance is x, and the image plane distance is z. The magnification m at this time is m = z / x
It is.

For recent good electron microscope with 5 Dan'yui image system used, the magnification M of the image projected onto the fluorescent screen is _{M = M OL · M IL1 ·} M IL2 · M IL3 · M PL
It is represented by Where M _OL is the magnification of the objective lens, M _IL1 is the magnification of the first intermediate lens, M _IL2 is the magnification of the second intermediate lens, M _IL3 is the _{magnification} of the third intermediate lens, and M _PL is the projection lens The expansion rate.

When an image is displayed on a TV monitor or PC monitor through a camera, if the magnetomotive number of the lens is J [AT], the relationship with the focal length f [mm] of the lens is approximately f = 25 (s + b ) / (J ² / U ^* )
It is known that Here, the gap distance s [mm] of the lens, the average hole diameter b [mm] of the lens, and the acceleration voltage U ^* [kV] corrected for relativity. FIG. 9 is a diagram showing an internal configuration of the electromagnetic lens. In the figure, 61 is a yoke, 62 is a pole piece (upper pole), 63 is a gap, 64 is a pole piece (lower pole), and 65 is a coil. Here, the average hole diameter b is represented by b = (b1 + b2) / 2 as the upper electrode hole diameter b1 and the lower electrode hole diameter b2. Here, the relativistic corrected acceleration voltage U ^* is

It is represented by Here, u is the acceleration voltage, e is the charge of the electrons, m is the mass of the electrons, and c is the speed of light.
Further, the image is not only magnified but also rotated by the action of the electromagnetic lens. In each electromagnetic lens, it is known that the image rotation angle θ [deg] exerted by the electromagnetic lens has the following relationship.

θ = 0.34J / U ^*
The image rotation angle on the fluorescent screen viewed from the sample is represented by the sum of the rotation angles of the respective lenses. In the case of a commonly used electron microscope with a five-stage imaging system, the angle θ formed between the sample and the image projected on the fluorescent screen is θ = θ _OL + θ _IL1 + θ _IL2 + θ _IL3 + θ _PL
It is represented by Here, θ _OL is the image rotation angle by the objective lens, θ _IL1 is the image rotation angle by the first intermediate lens, θ _IL2 is the image rotation angle by the second intermediate lens, θ _IL3 is the image rotation angle by the third intermediate lens, θ _PL is an image rotation angle by the projection lens. In an actual electron microscope, the excitation condition of each lens of the imaging system is set so that the angle of the image displayed as the sample is constant even if the magnification is changed.

Conventional devices of this type include an optical system that forms an image on a sample with a scanning optical system or irradiates a sample with an electron beam in the form of a probe and forms an image of the sample in front of or behind the sample. In addition, a scanning transmission electron microscope provided with magnification / rotation angle correction means for obtaining a transmission image having the same magnification / rotation angle based on the image obtained by the scanning transmission image is known (for example, a patent) Reference 2).
US Pat. No. 5,369,441 JP 2005-302415 A (paragraphs 0018 to 0027, FIG. 1)

  In the case of the conventional example 1 using the conventional apparatus shown in FIG. 8, when rotating the taken observation image, a method of rotating the sample was used, but the rotation axis of the sample and the center of the observation image field do not coincide with each other. The image is out of the field of view due to the rotation of the sample, and it is difficult to rotate the observation image within the same field of view.

  Further, in the case of Conventional Example 2, the range in which the observation image can be prevented from rotating according to the magnification is limited, and an image with a desired magnification can be obtained at a high magnification or a low magnification with respect to a medium magnification. In order to give priority, the resulting image is often rotated. Therefore, it is inevitable that the image rotates with enlargement at a certain magnification. FIG. 10 is an explanatory diagram of image rotation with magnification. (A) shows the case of the magnification range 1, and (b) shows the case of the magnification range 2. It can be seen that the image rotates as the magnification is increased. Further, the rotation angle is often set to be a constant rotation angle for each certain range rather than rotating for each magnification.

  The present invention has been made in view of such problems, and firstly provides a rotating mechanism of an electron microscope image observation camera capable of rotating an observation image to an arbitrary angle without changing the visual field. The purpose is that. Second, it is intended to provide a rotation mechanism of an electron microscope image observation camera that can prevent the image from rotating with respect to the entire observation magnification and can freely change the direction of the observation field of view according to the observation conditions. Yes.

  (1) The invention described in claim 1 is an electron microscope image observation camera for photographing and displaying an image on a fluorescent screen on which an electron microscope image is projected, and the camera is rotated about the lens optical axis of the camera. Rotating means for driving, rotating driving means for driving the rotating means, and control for controlling the rotation of the camera by giving a driving amount to the rotational driving means according to the magnitude and direction of rotation of the camera Means.

  (2) According to the second aspect of the present invention, each image forming system is arranged so that the rotation angle of the observation image through the sample and the camera is constant within the magnification range even if the magnification is varied within a certain magnification range. Storage means for storing lens alignment data for setting the excitation condition of the electromagnetic lens for each magnification range, and when a certain magnification is set, the lens alignment stored in the storage means according to the magnification range including the magnification The first calculation means for reading data and calculating the rotation angle of the image by the electromagnetic lens according to each magnification range, and the magnification range including the set magnification and the magnification range including the magnification after the magnification change Second calculating means for obtaining an angular difference of the rotation angle of the image by the electromagnetic lens, and the observation image displayed at the magnification after the magnification change is at the same angle as the observation image displayed at the set magnification. Displayed As, characterized in that so as to rotate the camera by the control unit based on the angular difference obtained by the second computing means.

  (3) According to the third aspect of the present invention, even if the magnification is varied within a certain magnification range, each angle of the imaging system is such that the angle between the sample and the observation image through the camera is constant within the magnification range. Using lens alignment data used for calculation for setting the lens excitation condition for each magnification range, the angle between the sample and the observation image obtained for each magnification range, and the sample and observation image in a certain magnification range A storage device that obtains an angle difference between the angle and the angle of the sample and the observation image in another magnification range in advance and stores it in the form of a table. When a certain magnification is set, the magnification range including the magnification is determined. Determining means, and determining the magnification range including the set magnification and the magnification range including the magnification after the magnification change by the determination means, and determining the magnification range including the set magnification and the magnification after the magnification change. Including magnification range Reading means for reading out the angle difference between the sample and the observation image from the table, and the observation image displayed at the magnification after the magnification change is the same as the observation image displayed at the set magnification The camera is rotated by the control means based on the angle difference read by the reading means so as to be displayed in an angle.

  (4) The invention according to claim 4 is characterized in that a first designation means for designating a straight line for defining a rotation angle of the observation image on a display screen for displaying the observation image by the camera; A second designating means for designating a straight line for defining a rotation angle to be rotated to a desired angle; and a second designating means for calculating an angle formed by the two straight lines designated by the first designating means and the second designating means. 3 based on the angle formed by the two straight lines obtained by the third computing means, and the control means rotates the camera so as to rotate the observation image to a desired angle. It is characterized by making it.

  (5) The invention according to claim 5 is characterized in that the camera is an electron microscope image observation camera that takes an electron microscope image from outside the vacuum using a 90-degree reflecting mirror below the fluorescent plate.

(1) According to the invention described in claim 1, since the photographing camera is rotated instead of the sample, the observation image can be rotated to an arbitrary angle without changing the visual field.
(2) According to the invention described in claim 2, even if the magnification of the image is changed, the rotation of the image can be prevented.

(3) According to the invention described in claim 3, the rotation angle of the image before and after the magnification change can be made the same.
(4) According to the invention described in claim 4, the observation image can be rotated to a desired angle.

  (5) According to the invention described in claim 5, an electron microscope image from the mirror can be taken with an electron microscope image observation camera using the 90-degree reflecting mirror below the fluorescent screen.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(Embodiment 1)
FIG. 1 is a block diagram showing a first embodiment of the present invention. The same components as those in FIG. 8 are denoted by the same reference numerals. In the figure, reference numeral 50 denotes an electron microscope mirror. The mirror body 50 includes a sample 41, a fluorescent plate 42 that visualizes a sample image, a mirror 43 that reflects a light signal from the fluorescent plate 42 in a 90-degree direction, and a glass 44 formed in the mirror body. Yes. A lens 46 receives and reflects the reflected signal from the mirror 43 through the glass 44.

  Reference numeral 45 denotes a camera that captures an image signal focused by the lens 46. As the camera 45, for example, a CCD camera is used. Reference numeral 47 denotes a member for fixing the camera 45 having one end attached to the surface of the mirror body 50. Reference numeral 49 is a bearing for rotating the camera 45, and 51 is a motor for rotating the camera 45. The motor 51 and the camera 45 are engaged by a gear, and when the motor 51 is rotated, the camera 45 is rotated.

  Reference numeral 48 denotes a control device such as a personal computer (PC) that takes in the captured image of the camera 45 and processes the image and receives each command to control the overall operation of the device shown in FIG. A camera rotation driver 52 receives the drive control signal from the control device 48 and rotates the camera 45. The camera rotation driver 52 generates a drive signal for rotating the motor 51. The configuration of the apparatus configured as described above will be described as follows.

  The apparatus shown in FIG. 1 rotates the electron microscope observation image shown in (a) as shown in FIG. 2 in the direction of the arrow in the figure, and a necessary image is obtained as shown in (b). It is intended to rotate. The electron microscope image reflected on the fluorescent screen 42 arranged in the electron microscope is reflected in the 90 ° direction by the mirror 43 provided in the lower part, and the image is taken by the camera 45 installed outside the electron microscope.

  The camera 45 is supported by a bearing 49 and rotates about the lens axis by driving a motor 51 through a gear. An image captured by the camera 45 is input to the control device 48. The input image is subjected to necessary image processing in the control device 48 and displayed on the display of the control device. Then, the rotation operation of the camera 45 is controlled by the camera rotation driver 52 connected to the control device 48. As a result, not the sample but the camera 45 is rotated, and the observation image can be rotated to an arbitrary angle without changing the field of view as shown in FIG.

  The observer inputs a desired rotation angle from the control device 48. At this time, the rotation angle of the motor 51 is set as follows from the display screen of the control device 48. Now, as shown in FIG. 3, the graphic shown in the screen (a) is displayed on the control device. This figure is rotated as shown in FIG.

Line segments P ₁ and P ₂ for designating the inclination on the screen are selected. The coordinates of P ₁ are (x ₁ , y ₁ ),
The coordinate of P ₂ is (x ₂ , y ₂ ). The equation of the straight line passing through these two points P ₁ and P ₂ is expressed by the following equation.

This is matched with an arbitrary straight line expression. Arbitrary points P ₃ and P ₄ are designated on the screen. The coordinates of P ₃ are (x ₃ , y ₃ ), and the coordinates of P ₄ are (x ₄ , y ₄ ). The equation passing between these two points is expressed by the following equation.

From equations (2) and (3), the angle θ between these two straight lines is

It becomes.
Since the motor 51 rotates the camera 45 using a gear, between the rotation angle φ of the motor 51 and the rotation angle θ of the camera 45,
θ = kφ (5)
The relationship that became. Here, k is a gear reduction ratio. Therefore, the rotation angle φ of the motor is

Given in. Thus, the observation image can be arbitrarily rotated by setting the rotation angle φ of the motor and performing the rotation operation.
(Embodiment 2)
FIG. 4 is a diagram illustrating a configuration example of a transmission electron microscope. In the figure, 1 is an electron source for generating an electron beam, 2 is an acceleration tube for accelerating the electron beam, 3 is a focusing lens for focusing the electron beam, and 4 is for supplying a current to the focusing lens 3. A focusing lens power source 5 is a first focusing lens alignment, 6 is a second focusing lens alignment, and 7 is a focusing lens alignment power source for supplying current to the focusing lens alignments 5 and 6.

  Reference numeral 8 denotes an objective lens provided under the focusing lens alignment, 9 denotes an objective lens power source for supplying a current to the objective lens 8, and 10 denotes a sample. Reference numeral 11 denotes a first intermediate lens provided on the lower side of the sample 10, 12 denotes a first intermediate lens power supply for supplying a current to the first intermediate lens 11, and 13 denotes a first intermediate lens disposed below the first intermediate lens 11. 2 intermediate lens, 14 is a second intermediate lens power source for supplying current to the second intermediate lens 13, 15 is a third intermediate lens disposed below the second intermediate lens 13, and 16 is connected to the third intermediate lens 15. A third intermediate lens power supply for supplying current.

  17 is a projection lens disposed below the third intermediate lens 15, 18 is a projection lens power source for supplying current to the projection lens 17, 19 is a rotating flange, 20 is a rotating flange rotating motor, and 21 is a rotating flange rotating motor. A motor power supply / controller that supplies power to the motor 20, 22 is a flange rotation detector that detects the rotation of the flange 19, and 23 is an electron microscope image / electron diffraction pattern acquisition camera. As the electron microscope image / electron diffraction pattern acquisition camera 23, for example, a TV rate camera or a slow scan CCD camera is used.

  24 is a camera controller for controlling the camera 23, 25 is a control device such as a personal computer (PC) for controlling the operation of the entire system, 26 is an electron microscope operation / image capturing software, and 27 is an alignment for storing data for alignment. A storage area 28 is an image storage area for storing an image, and is provided in the control device 25. Reference numeral 29 denotes an observation image display and an electron microscope operation screen (display), and 30 denotes an operation panel including an electron microscope operation panel and a keyboard. The motor power supply controller 21, the flange rotation detector 22, the camera controller 24, and the control device 25 are connected by signal lines.

  Since the camera 23 is fixed to the flange 19 but is rotatable, the observation field of view can be rotated for observation. In the second embodiment, the case where the CCD camera body is rotated is shown, but the same effect can be obtained even if only the CCD camera element is rotated. It is assumed that the rotation center of the camera coincides with the center of the CCD element, that is, the visual field, and also coincides with the enlargement center of the electron microscope enlargement system. The operation of the apparatus configured as described above will be described as follows.

  As shown in FIG. 5, a magnification range 1, a magnification range 2, and two magnification ranges are considered. At the magnifications included in the respective magnification ranges, the image is not rotated and only enlargement / reduction is performed. The current setting of each lens of the imaging system at each magnification is performed as follows.

  An observer operates an electron microscope operation panel and a keyboard (hereinafter referred to as an operation panel) 30 while viewing an observation image display and an electron microscope image operation screen (hereinafter referred to as an operation screen) 29 to set a necessary magnification. The control device 25 stores the input magnification. The control device 25 reads the current setting value (for example, the magnetomotive number [AT]) of each lens at a certain magnification from the alignment storage area 27.

FIG. 6 is a diagram showing an example of stored data in the alignment data storage area. As shown in the figure, for each magnification range, a current setting value of each electromagnetic lens necessary for setting a magnification in a certain magnification range is stored. In the figure, in the magnification range 1, J _OL is the magnetomotive number [AT] of the objective lens, J _IL1 is the magnetomotive number of the first intermediate lens, J _IL2 is the magnetomotive number of the second intermediate lens, and J _IL3 is the first _{magnetomotive} number. 3 of the intermediate lens caused磁数, J _PL is raised磁数of the projection lens. The magnetomotive number setting values of the respective lenses are aligned with a ₁₁ , a ₁₂ , a ₁₃ , a ₁₄ , and a ₁₅ . Such an arrangement of data is the same for the magnification range 2.

For this cause磁数data, in order to set the magnification 1, an electromotive磁数objective lens in a _11, the electromotive磁数the first intermediate lens in a _12, the electromotive磁数second intermediate lens In a ₁₃ , it is shown that a magnification range 1 can be obtained by setting the magnetomotive number of the third intermediate lens to a ₁₄ and setting the magnetomotive number of the projection lens to a ₁₅ . The same applies to the setting of the magnetomotive number when the magnification range 2 is obtained.

  The control device 25 reads the magnetomotive number data stored in the alignment data storage area 27 and supplies the data to the imaging system lens power supplies 9, 12, 14, 16, 18 so as to set the corresponding current values. Send it out. A magnification is obtained by setting a desired magnetomotive number from each imaging system lens power source and passing a current through the coils constituting the respective lenses 8, 11, 13, 15, and 17.

Here, the image rotation angle θ [deg] on the imaging surface of the electron microscope image acquisition camera 23 with respect to the sample 10 is obtained by the following equation.
θ = θ _OL + θ _IL1 + θ _IL2 + θ _IL3 + θ _PL (7)
Here, θ _OL is the image rotation angle by the objective lens, θ _IL1 is the image rotation angle by the first intermediate lens,
θ _IL2 is an image rotation angle by the second intermediate lens, θ _IL3 is an image rotation angle by the third intermediate lens, and θ _PL is an image rotation angle by the projection lens.

Further, it is known that the relationship between the electromagnetic lens magnetomotive number [AT] and the image rotation angle θ [deg] by the one-stage electromagnetic lens is expressed by the following equation.
θ = 0.34J / U ^* (8)
Therefore, the image rotation angle θ can be expressed as follows using the number of magnetomotive forces and the equation (8).

θ = θ _OL + θ _IL1 + θ _IL2 + θ _IL3 + θ _PL
^{= (0.34 / U *) ·} (J OL + J IL1 + J IL2 + J IL3 + J PL) (9)
Here, U ^* is the relativistic corrected acceleration voltage [kV], J _OL is the magnetomotive number [AT] of the objective lens, J _IL1 is the magnetomotive number of the first intermediate lens, and J _IL2 is the second intermediate lens. causing磁数, J _IL3 is caused磁数, J _PL of the third intermediate lens is caused磁数of the projection lens. As described above, it can be understood that each magnification, that is, the rotation angle in the magnification range can be calculated from the data stored in the alignment data storage area 27.

When the rotation angle in the magnification range 1 is θ ₁ and the rotation angle in the magnification range 2 is θ ₂ , the angle difference θ _d between the two magnification ranges is θ _d = θ ₂ −θ ₁ (10)
It is a constant value.

  On the other hand, an electron microscope image / electron diffraction pattern acquisition camera (hereinafter simply referred to as a camera) 23 attached via a rotation flange 19 can be rotated by a rotation flange rotation motor (hereinafter simply referred to as a motor) 20. Since the rotary flange 19 needs to be vacuum resistant and rotatable, for example, a magnetic fluid or the like is used as a sealant.

  The motor 20 and the flange 19 are engaged with each other by a gear, and the rotation angle of the motor 20 and the rotation angle of the flange 19 need to be in a proportional relationship. Therefore, the motor 20 and the flange 19 are proportional to the rotation angle of the motor 20. The flange 19 rotates. Here, the rotation angle φ of the flange 19 is expressed by the following equation, where α is a proportionality constant (correction constant) and the rotation angle of the motor is Q.

φ = α ・ Q (11)
Since the rotation angle φ of the flange 19 and the rotation angle difference θ _d depending on the lens magnification range need only be the same, the rotation angle Q of the motor 20 is set so that the observation image does not rotate across the magnification range. ,
Q = φ / α = θ _d / α = (θ ₂ −θ ₁ ) / α (12)
Set to be. With this setting, the rotation angle of the observation image based on the magnification range and the rotation angle Q of the motor using the motor 20 are equal, so that the image can be prevented from rotating with respect to the entire observation magnification. Actually, the output to the stepping motor or the servo motor is performed so that the above Q is obtained.

  In the above description, as a method for correcting the rotation of the observation image associated with the change in the magnification range, the difference between the image rotation angle in each magnification range and the image rotation angle between different magnification ranges is calculated using the formula each time the magnification is changed. To calculate. However, it is not always necessary to calculate each time, and there is a method in which necessary calculations are performed in advance, for example, a table as shown in FIG. 11 is created for each acceleration voltage. In FIG. 11, the horizontal column represents the magnification range (subscript i) before the magnification change, and the vertical column represents the magnification range (subscript j) after the magnification change.

θ ₁ and θ ₂ are angles corresponding to, for example, θ ₁ and θ ₂ in equation (10). Further, for example, θ ₃₁ is the angle difference of the observation image when the magnification included in the magnification range 3 is changed to the magnification included in the magnification range 1, and corresponds to θ _d in the equation (10). Since there is a relationship of θ ₁₃ = −θ ₃₁ , for example, θ ₃₁ or the like may be placed on the table, and when the change of the magnification range is reverse, the reverse sign may be attached. If a table such as that shown in FIG. 11 is used, when a certain magnification is set, a necessary camera rotation angle can be easily obtained simply by determining which magnification range the magnification is included in.

  By applying the method of the second embodiment described above, the observation visual field can be rotated at an arbitrary angle. For example, there is a high demand for capturing an image in which a part of a sample is in a horizontal or vertical direction. This will be described as an example. It is assumed that an inclined figure (field of view) such as a two-dot chain line in FIG. 7 is rotated so that one side is horizontal as indicated by a solid line. This figure is displayed on the monitor 29 of FIG.

Line segments P ₅ (x ₁ , y ₁ ) and P ₆ (x ₂ , y ₂ ) are designated so that the horizontal portions of the inclined figure (field of view) should be overlapped. The slope θ _d of the line segment P5-P6 is obtained as follows.
θ _d = tan ⁻¹ {(y ₂ −y ₁ ) / (x ₂ −x ₁ )} (13)
It becomes.

Now, when the rotation is changed by changing the magnification and switching the magnification range,
Q = tan ⁻¹ [{(y ₂ −y ₁ ) / (x ₂ −x ₁ )} / α] + {(θ ₂ −θ ₁ ) / α}
(14)
Is set so that the observer can observe without being aware of the rotation of the image due to the change of the magnification range.

It is a block diagram which shows the 1st Embodiment of this invention. FIG. 6 shows image rotation according to the present invention. It is a figure which shows a mode that an observation image is rotated to arbitrary angles, without changing a visual field. It is a figure which shows the structural example of a transmission electron microscope. It is a figure which shows the memory | storage data example of an alignment data storage area. It is a figure which shows the angle difference in two magnification ranges. It is explanatory drawing of rotation to arbitrary angles. It is a figure which shows the structural example of a conventional apparatus. It is a figure which shows the internal structure of an electromagnetic lens. It is explanatory drawing of the image rotation accompanying a magnification. It is a figure which shows the relationship between the magnification range before magnification change, and the magnification range after magnification change.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electron source 2 Accelerating tube 3 Focusing lens 4 Focusing lens power supply 5 First focusing lens alignment 6 Second focusing lens alignment 7 Focusing lens alignment power supply 8 Objective lens 9 Objective lens power supply 10 Sample 11 First intermediate lens 12 First intermediate lens power supply DESCRIPTION OF SYMBOLS 13 2nd intermediate lens 14 2nd intermediate lens power supply 15 3rd intermediate lens 16 3rd intermediate lens power supply 17 Projection lens 18 Projection lens power supply 19 Rotation flange 20 Rotation flange rotation motor 21 Motor power supply / controller 22 Flange rotation angle detector 23 Electron microscope image / electron diffraction pattern acquisition camera 24 Camera controller 25 Controller 26 Electron microscope operation / image capture software 27 Alignment data storage area 28 Image storage area 29 Observation image display and electron microscope operation screen 30 Electron microscope Created panel and keyboard

Claims (5)

An electron microscope image observation camera for photographing and displaying an image on a fluorescent screen on which the electron microscope image is projected;
Rotating means for rotating the camera about the optical axis of the lens of the camera;
Rotation drive means for driving the rotation means;
An electron microscope comprising: control means for controlling the rotation of the camera by giving a drive amount corresponding to the rotation angle and direction of rotation of the camera to the rotation driving means. Lens alignment data that sets the excitation conditions for each electromagnetic lens in the imaging system so that the rotation angle of the observation image through the sample and the camera is constant within the magnification range even if the magnification is varied within a certain magnification range Storing means for each magnification range;
When a certain magnification is set, the lens alignment data stored in the storage means is read out according to the magnification range including the magnification, and the rotation angle of the image by the electromagnetic lens according to each magnification range is calculated. 1 computing means;
A second computing means for obtaining an angular difference of an image rotation angle by the electromagnetic lens between a magnification range including a set magnification and a magnification range including a magnification after the magnification change;
Based on the angle difference obtained by the second calculating means so that the observation image displayed at the magnification after the magnification change is displayed at the same angle as the observation image displayed at the set magnification. 2. The electron microscope according to claim 1, wherein the camera is rotated by the control means. Excitation conditions for each electromagnetic lens of the imaging system are set for each magnification range so that the angle between the sample and the observation image through the camera is constant within the magnification range even if the magnification is varied within a certain magnification range. The angle of the sample and the observation image obtained for each magnification range using the lens alignment data used for the calculation for the above, the angle of the sample and the observation image in a certain magnification range, and the sample and observation in another magnification range A storage device that obtains an angle difference from the image angle in advance and stores it in the form of a table;
Determining means for determining a magnification range including the magnification when a certain magnification is set;
The determination means determines the magnification range including the set magnification and the magnification range including the magnification after the magnification change, and the magnification range including the set magnification and the magnification range including the magnification after the magnification change. Readout means for reading out the angle difference between the sample and the observation image from the table,
The control based on the angular difference read by the reading means so that the observation image displayed at the magnification after the magnification change is displayed at the same angle as the observation image displayed at the set magnification. The electron microscope according to claim 1, wherein the camera is rotated by means. First display means for specifying a straight line for defining a rotation angle of the observation image and a rotation angle for rotating the observation image to a desired angle on a display screen for displaying an observation image by the camera. A second designation means for designating a straight line for
A third calculating means for calculating an angle formed by two straight lines specified by the first specifying means and the second specifying means;
The camera is rotated by the control means so as to rotate the observation image to a desired angle based on an angle formed by the two straight lines obtained by the third calculation means. 1. The electron microscope according to 1.   The electron microscope according to any one of claims 1 to 3, wherein the camera is an electron microscope image observation camera that takes an electron microscope image from outside the vacuum using a 90-degree reflection mirror below the fluorescent plate.

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