JP3375035B2 - TV camera system for electron microscope - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a TV for an electron microscope for observing an image of a sample with a TV camera in the electron microscope.
Related to camera system. 2. Description of the Related Art In recent years, in an electron microscope, an image of a sample is picked up by a TV camera and displayed on a monitor for observation. The TV camera may be arranged on the upstream side of the fluorescent screen, or may be arranged on the downstream side of the fluorescent screen. In the former case, a wide-field image is obtained. Has a feature that a high-resolution and high-sensitivity image can be obtained. FIG. 5 is a diagram showing an example of the configuration, in which camera heads are arranged on both the upstream side and the downstream side of a fluorescent screen. In the figure, 1 is a lens barrel, 2 is a fluorescent screen, 3 and 4 are camera heads, and O is an optical axis. It is assumed that the camera heads 3 and 4 are always operating when the electron microscope is used. Further, as is well known, the imaging unit of the camera head 3 has a configuration in which a layer that emits light when electrons such as phosphors are irradiated on the surface of the CCD is provided. In addition, an image intensifier is provided on the CCD in order to secure luminance. The camera head 3 arranged on the upstream side of the fluorescent screen 2 is located at a position indicated by A in FIG. 5 when an image of a sample (not shown in FIG. 5) is not taken. Is imaged, it is moved to the position B indicated by the broken line in the figure. When the camera head 3 is at the position B in the figure, an image captured by the camera head 3 is displayed on a monitor (not shown in FIG. 5). A camera head 4 disposed downstream of the fluorescent screen 2 is fixed to the lower surface of the lens barrel 1. Therefore, when the fluorescent screen 4 is in the state shown by the solid line in the figure, the camera head 4 cannot capture an image of the sample. As shown by the broken line. Therefore, when the fluorescent screen 2 is in the state shown by the broken line in the figure, the image of the sample taken by the camera head 4 is displayed on the monitor. As is apparent from the above description, when the image of the sample is observed on the fluorescent screen 2, the camera head 3 or the camera head 4 is not irradiated with an electron beam. Therefore, an image of the sample cannot be captured, and the screen of the monitor becomes black. Also, the camera head 3 is moved from the position shown in FIG. 5B to the position shown in FIG. 5A, or vice versa, or the camera head 3 is moved from the position shown in FIG. During the operation, the image of the sample picked up by the camera head 3 flows, and a normal image of the sample cannot be obtained. Similarly, the fluorescent screen 2 is moved from the position indicated by the solid line to the position indicated by the broken line in FIG. The fluorescent screen 2 enters the field of view of the camera head 4 while moving the fluorescent screen 2 from the position shown by the broken line in FIG. The image of the sample cannot be captured normally. That is, the observation of the image of the sample on the fluorescent screen 2 and the observation of the image of the sample captured by the camera head 3 or the camera head 4 are incompatible. In an electron microscope, the magnification, the accelerating voltage, or various observation conditions may be changed. In these cases, the image of the sample on the fluorescent screen 2 and the camera head are changed. In some cases, it is required to compare and observe the image of the sample captured by the camera head 3 or the camera head 4. This is incompatible with the observation of the image of the sample that has been picked up, so that there has been a problem that the above requirements cannot be met. The electron microscope is arranged in a dark room, and observation of an image displayed on a monitor is usually performed in the dark room. Conventionally, an image of a sample picked up by the camera head 3 is displayed on the monitor. There is a problem that the luminance change of the monitor is large between when displaying and when the camera head 3 is at the position shown in FIG. 5A and the image of the sample cannot be taken, which is not desirable for the visual function of the observer. there were. This is because when the image of the sample picked up by the camera head 4 is displayed on the monitor, the fluorescent screen 2 is shown in FIG.
The same applies to the case where the image of the sample cannot be captured by the camera head 4 in the state shown by the solid line. That is, as described above, when the camera head 3 is set at the position shown in FIG. 5B and an image of the sample is taken, the camera head 3 is used to observe the image of the sample on the fluorescent screen 2. Assuming that the sample 3 is moved to the position shown in FIG. 5A, the image of the sample is initially displayed on the screen of the monitor, but the image of the sample gradually moves as the camera head 3 moves. Since it deviates from the field of view, the electron beam is not irradiated on the camera head 3 eventually, and the screen of the monitor becomes black, which is compared with when the image of the first sample is displayed. A large change in luminance will occur. It is apparent that such a large change in the brightness of the monitor screen in a dark room is not desirable because it means a great change in the visual environment of the observer. Similarly, the fluorescent screen 2 is tilted in order to observe the image of the sample on the fluorescent screen 2 from the state where the image of the sample is captured by the camera head 4 while the fluorescent screen 2 is in the state of the broken line in FIG. In the state shown by the solid line in FIG. 5, the image of the sample is first displayed on the monitor screen, but as the fluorescent screen 2 falls, the fluorescent screen 2 enters the field of view of the camera head 4, and The field of view of the camera head 4 is narrowed, and eventually the electron beam is not irradiated on the camera head 4 and the screen of the monitor becomes black, and the image of the first sample is displayed. As compared with the case, a large change in luminance occurs, and the visual environment of the observer changes greatly. The present invention has been made to solve the above-mentioned problems, and it is possible to display an image of a sample on a monitor even when the image of the sample is observed on a fluorescent screen. It is an object of the present invention to provide a TV camera system for an electron microscope that does not greatly change the image quality. [0014] To achieve the above object, a TV camera system for an electron microscope according to the present invention is a TV camera system for an electron microscope for observing an image of a sample with the TV camera in the electron microscope. The TV camera
Equipped with a memory for writing the sample image taken at
If the sample image cannot be normally captured by the TV camera , the sample image written in the memory is monitored.
Is displayed. Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a view showing a first embodiment of a TV camera system for an electron microscope according to the present invention, and is a view showing an embodiment in which a camera head is arranged on an upstream side of a fluorescent screen. Reference numeral 10 denotes a camera head, 11 denotes a driving unit, 12 denotes a button switch, 1
3 is a control unit, 14 is a monitor, 20 is a control unit, 21 is a timing signal generation unit, 22 is a signal processing unit,
23 is a frame memory, 24 is a switch, 25 is A / D
A converter, 26 indicates a D / A converter, and O indicates an optical axis of the electron microscope. First, each part of the configuration shown in FIG. 1 will be described. The camera head 10 may have the same configuration as the conventional camera head shown at 3 in FIG.
Various timing signals for driving 0 are supplied from the timing signal generator 21 of the control unit 13. Then, the video signal output from the camera head 10 is input to the signal processing unit 22 of the control unit 13. The positions indicated by A and B in FIG. 1 indicate the same positions as the positions of the camera heads indicated by A and B in FIG. 5, respectively. The driving section 11 is for moving the position of the camera head 10, and here, it is assumed that the position of the camera head 10 is moved by air pressure. The operation of the drive unit 11 is controlled by the control unit 20 of the control unit 13. A button switch 12 is an operation button for setting whether or not to capture an image of a sample with the camera head 10, and is arranged on an operation panel of the electron microscope. As shown in the figure, a low level is output when the apparatus is in the closed state, and a high level is output when the apparatus is in the open state as shown by the solid line in FIG. When the camera head 10 captures an image of the sample, the sample is closed as indicated by a broken line in the figure, and when no image is captured, the sample is opened as illustrated by a solid line in the figure. The control unit 13 includes the control unit 2
0, a timing signal generator 21, a signal processor 22, a frame memory 23, and a switch 24. The control unit 20 is composed of a processing unit and its peripheral circuits.
To control the drive unit 11, the frame memory 23, and the switch 24. The details will be described later. The timing signal generator 21 includes various timing signals necessary for driving the camera head 10;
A horizontal synchronization signal, a vertical synchronization signal, etc. are generated.
Various timing signals necessary for driving the camera head 10 are supplied to the camera head 10, at least a vertical synchronization signal is supplied to the control unit 20, and a horizontal synchronization signal is supplied to the signal processing unit 22. A timing signal necessary for generating a video signal of a predetermined format such as a signal and a vertical synchronization signal is supplied. The signal processing section 22 performs predetermined various processing such as gain adjustment on the video signal input from the camera head 10 to generate and output a video signal of a predetermined format. Next, the operation of each unit having the configuration shown in FIG. 1 will be described with reference to the timing chart shown in FIG. Now, it is assumed that the camera head 10 is at the position shown by B in FIG. 1 as shown in FIG. 2C. At this time, the button switch 12 is closed as shown by the broken line in FIG. 1 ((a) in FIG. 2), and the switch 24 is
0 indicates that the a side is selected as shown by the broken line in FIG. 1 (FIG. 2D). Therefore, at this time, a live image is displayed on the monitor 14. Note that the live image means an image that is currently being captured by the camera head 10. Hereinafter, the same applies. Then, as shown in FIG.
It is assumed that the button switch 12 is operated to ₀ and opened as shown by the solid line in FIG. At this time, the button switch 12 outputs a high level. When the control unit 20 detects that the output from the button switch 12 has changed from the low level to the high level, first, the vertical synchronization from the timing signal generation unit 21 is performed. Referring to the signal, FIG.
As shown at 27 in FIG.
An image of one frame of the video signal digitized by the / D converter 25 is written to the frame memory 23. At the same time when the writing of one frame image into the frame memory 23 is completed (t _{1 in} FIG. 2B), the switch 24 is connected to the b side as shown in FIG. The still image written in the memory 23 is read, and the camera head 10
Is pulled back to the position indicated by A in FIG. Upon receiving an instruction from the control unit 20, the driving unit 1
1 performs an operation of pulling back the camera head 10 from the position shown by B in FIG. 1 to the position shown by A in FIG. 2C, and at this time, the monitor 14 is moved to the monitor 14 as shown in FIG. Are read out from the frame memory 23, and a still image converted into analog by the D / A converter 26 is displayed. Then, as shown in FIG.
Button switch 12 at time t ₂ is operated and is closed as indicated by the broken line in FIG. 1. At this time, a low level is output from the button switch 12, but the control unit 2
0 detects that the output from the button switch 12 has changed from the high level to the low level.
1 is instructed to move the camera head 10 from the position indicated by A in FIG. Upon receiving an instruction from the control unit 20, the driving unit 1
1 performs the operation of inserting the camera head 10 from the position indicated by B in FIG. 1 to the position indicated by A, as indicated by 29 in FIG. 2C. It is detected that the camera is positioned at the indicated imaging position (t in FIG. 2C).
₃ ) and the switch 24 is connected to the a side as shown in FIG. As a result, the image displayed on the monitor 14 is switched from a still image read from the frame memory 23 to a live image as shown in FIG. Various methods are conceivable for the control unit 20 to detect that the camera head 10 is located at the imaging position shown in FIG. 1B, and an appropriate method may be adopted. For example, a means for measuring the current position of the camera head 10 is provided in the drive unit 11, and the position information of the camera head 10 detected by the measuring means is notified to the control unit 20. According to this, the control unit 20 can recognize what position the camera head 10 is currently located. The following method is also conceivable. That is, since the distance between the position indicated by A in FIG. 1 and the imaging position indicated by B is determined, it is determined in advance how long the driving unit 11 operates to reach the imaging position indicated by B from the position indicated by A. You can ask. Therefore, the control unit 20 causes the drive unit 11 to perform a process of measuring the time from when the operation start instruction is given. According to this, the control unit 2
A value of 0 makes it easy to determine whether the camera head 10 is located at the imaging position indicated by B in FIG. According to the above operation, when the camera head 10 is at the image pickup position shown in FIG. 1B and can normally pick up an image of the sample, a live image is displayed on the monitor 14. However, when the camera head 10 is not at the imaging position shown in FIG. 1B and is in a state where the image of the sample cannot be normally captured, specifically, when the camera head 10 is at the position shown in A in FIG. When the camera head 10 is in the middle of being pulled back from the imaging position indicated by B in FIG. 1 to the position indicated by A, and when the camera head 10 is inserted from the position indicated by A in FIG. If the monitor 14 is in the middle of moving,
Will be displayed. Therefore, even when the image of the sample is observed on the fluorescent screen (not shown in FIG. 1), a still image of the sample can be observed on the monitor 14, so that various observations of the electron microscope can be performed. When changing the conditions, the image of the sample on the fluorescent screen and the still image displayed on the monitor 14 can be compared and observed. Further, since the image displayed on the monitor 14 is instantaneously switched from a live image to a still image or vice versa, the brightness of the monitor 14 does not greatly change as in the prior art, so The visual environment does not change significantly. The first embodiment of the present invention has been described above. Next, a second embodiment of the present invention will be described. FIG. 3 is a view showing a second embodiment of a TV camera system for an electron microscope according to the present invention, and is a view showing an embodiment in which a camera head is arranged on the downstream side of a fluorescent screen. In the figure, 30 is a fluorescent screen,
Reference numeral 31 denotes a camera head, 32 denotes a drive unit, and 33 denotes a button switch. Note that the same components as those shown in FIG. 1 are denoted by the same reference numerals as those in FIG. The camera head 31 may have the same configuration as the conventional camera head shown at 4 in FIG. 5, but here, various timing signals for driving the camera head 31 are transmitted from the timing signal generator 21 of the control unit 13. Shall be supplied. Then, the video signal output from the camera head 31 is input to the signal processing unit 22 of the control unit 13. The driving section 32 drives the fluorescent screen 30 from a state shown by a solid line in FIG. 3 to a state shown by a broken line or vice versa by a predetermined driving method such as air pressure. The operation of 32 is controlled by the control unit 20 of the control unit 13. The button switch 33 is an operation button for setting whether or not to capture an image of the sample with the camera head 31. The button switch 33 is arranged on the operation panel of the electron microscope. As shown in the figure, a low level is output when the apparatus is in the closed state, and a high level is output when the apparatus is in the open state as shown by the solid line in FIG. When the camera head 31 captures an image of a sample, the sample is closed as shown by a broken line in the figure, and when no image is captured, it is opened as shown by a solid line in the figure. Next, the operation of each unit having the configuration shown in FIG. 3 will be described with reference to the timing chart shown in FIG. Now, it is assumed that the fluorescent screen 30 is at the position shown by the broken line in FIG. 3 as shown in FIG. At this time, the button switch 33 is closed as shown by the broken line in FIG. 3 ((a) in FIG. 4), and the switch 24 is selected by the control unit 20 on the a side as shown by the broken line in FIG. (D)). Therefore, at this time, the monitor 14
Shows a live image captured by the camera head 31. Then, as shown in FIG.
It is assumed that the button switch 33 is operated at ₀ and opened as shown by the solid line in FIG. At this time, a high level is output from the button switch 33. When the control unit 20 detects that the output from the button switch 33 has changed from the low level to the high level, first, the vertical synchronization from the timing signal generation unit 21 is performed. Referring to the signal, FIG.
As shown at 36 in FIG.
An image of one frame of the video signal digitized by the / D converter 25 is written to the frame memory 23. At the same time when the writing of one frame image into the frame memory 23 is completed (t _{1 in} FIG. 4B), the switch 24 is connected to the b side as shown in FIG. The still image written in the memory 23 is read and the fluorescent screen 3
0 is returned to the position shown by the solid line in FIG. Upon receiving an instruction from the control unit 20, the driving unit 3
2 is a fluorescent screen 30 as indicated by 35 in FIG.
3 is returned from the position shown by the broken line in FIG. 3 to the position shown by the solid line. At this time, as shown in FIG.
The still image analogized by the / A converter 26 is displayed. Then, as shown in FIG.
Button switch 33 at time t ₂ is operated and is closed as indicated by the broken line in FIG. At this time, a low level is output from the button switch 33.
0 detects that the output from the button switch 33 has changed from a high level to a low level.
2 is instructed to move the fluorescent screen 30 from the position shown by the solid line in FIG. 3 to the position shown by the broken line. Upon receiving an instruction from the control unit 20, the driving unit 3
2 is a fluorescent screen 30 as indicated by 36 in FIG.
Is moved from the position shown by the solid line in FIG. 3 to the position shown by the broken line. The control unit 20 detects that the fluorescent screen 30 is positioned at the position shown by the broken line in FIG.
(C ₃ ) and the switch 2 as shown in FIG.
4 is connected to a side. As a result, as shown in FIG. 4E, the image displayed on the monitor 14 is obtained from the still image read from the frame memory 23 by the camera head 31.
Is switched to the live image captured by. Various methods are conceivable for the control unit 20 to detect that the fluorescent screen 30 is located at the position shown by the broken line in FIG. 3, and an appropriate method may be adopted. For example, a means for measuring the current position of the fluorescent screen 30 is provided in the drive unit 32, and the position information of the fluorescent screen 30 detected by the measuring means is notified to the control unit 20. According to this, the control unit 20 can recognize what position the fluorescent screen 30 is currently located. The following method is also conceivable. That is, since the positional relationship between the position indicated by the solid line and the position indicated by the broken line in FIG.
It is possible to determine in advance how long the device 2 will operate from the position indicated by the solid line to the position indicated by the broken line in FIG. Therefore, the control unit 20 performs a process of measuring the time after giving the operation start instruction to the drive unit 32. According to this, the control unit 20 can easily determine whether the fluorescent screen 30 is located at the position indicated by the broken line in FIG. According to the above operation, the fluorescent screen 30
Is located at the position shown by the broken line in FIG. 3 and a live image can be displayed on the monitor 14 when the camera head 31 can normally capture an image of the sample.
0 is not at the position shown by the broken line in FIG. 3 and the image of the sample cannot be taken normally, specifically, when the fluorescent screen 30 is at the position shown by the solid line in FIG. 3 and the fluorescent screen 30 is being pulled up from the position shown by the solid line to the position shown by the broken line in FIG. In this case, the still image written in the frame memory 23 is displayed on the monitor 14. Therefore, even when the image of the sample is observed on the fluorescent screen 30, a still image of the sample can be observed on the monitor 14, so that when the various observation conditions of the electron microscope are changed, the fluorescent screen is used. And the still image displayed on the monitor 14 can be compared and observed. Further, the image displayed on the monitor 14 is instantaneously switched from a live image to a still image, or vice versa. The visual environment does not change significantly.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing a first embodiment of a TV camera system for an electron microscope according to the present invention, in which a camera head is arranged on an upstream side of a fluorescent screen. FIG. FIG. 2 is a timing chart showing the operation of the configuration shown in FIG. FIG. 3 is a view showing a second embodiment of the TV camera system for an electron microscope according to the present invention, in which the camera head is arranged on the downstream side of a fluorescent screen. FIG. 4 is a timing chart showing the operation of the configuration shown in FIG. FIG. 5 is a diagram showing a configuration example in a case where an image of a sample is captured by a TV camera in an electron microscope. [Description of Signs] 1 ... barrel, 2 ... fluorescent screen, 3 ... camera head, 10 ... camera head, 11 ... drive unit, 12 ... button switch, 13 ... control unit, 14 ... monitor, 20 ... control unit , 21... Timing signal generator, 22
... Signal processing unit, 23 ... Frame memory, 24 ... Switch, 25 ... A / D converter, 26 ... D / A converter, 30 ...
Fluorescent screen, 31: camera head, 32: drive unit,
33: Button switch, O: Optical axis of the electron microscope.

Continued on the front page (72) Inventor Masanobu Shirakawa 5-6-16 Ikegami, Ota-ku, Tokyo Ikegami Communication Equipment Co., Ltd. Ikegami Factory (72) Inventor Katsuji Ienaga 3-1-2 Musashino, Akishima City, Tokyo Japan (56) References JP-A-3-46744 (JP, A) JP-A-8-111201 (JP, A) JP-A-63-84864 (JP, U) (58) Fields surveyed (Int .Cl. ⁷ , DB name) H01J 37/22

Claims (1)

(57) [Claims] 1. An image of a sample in an electron microscope is taken by a TV camera.
A TV camera system for an electron microscope for observing the sample image by using a camera for writing a sample image picked up by the TV camera.
And a monitor for displaying an image of the sample written in the memory on a monitor when the TV camera is in a state where the image of the sample cannot be normally captured by the TV camera. Camera system.