JPH0992194A - Electron microscope with TV camera - Google Patents

Abstract

(57) 【Abstract】 PROBLEM TO BE SOLVED: To constantly improve the operability of an electron microscope with a television camera by keeping the brightness of a television monitor constant. A transmission electron microscope, a television camera 10 mounted on the transmission electron microscope, and a controller 11 of the television camera 10.
The arithmetic control unit 17 for controlling the video signal, the means for outputting the average brightness of the video output of the television camera 10, and the means for outputting the level of the AC signal of the video signal. It is communicated to the device 19 and controls the electron microscope based on this information.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron microscope which irradiates a sample with an electron beam to magnify the electron beam transmitted through the sample and observes or records the electron beam with a television camera. The present invention relates to an electron microscope having improved operability by enhancing a communication function.

[0002]

2. Description of the Related Art An electron microscope image is C in a recent electron microscope.
Television cameras are increasingly used because they can be viewed brightly on RT monitors. The television camera is usually attached to the lower part of the camera room of the electron microscope and observes a magnified image of the electron beam transmitted through the sample. However, in such a case, it is necessary to operate the electron microscope and the television camera independently. For example, when the magnification of the electron microscope is changed, the brightness of the electron beam on the television camera changes, so the magnification is changed. It was necessary to change the observation conditions such as changing the gain of the TV camera each time.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to make it possible to observe an electron microscope image on a monitor without changing the observation condition of a television camera each time the magnification of the electron microscope or the observation mode is changed. To provide a microscope.

[0004]

According to the present invention, a communication circuit is provided between a control system of an electron microscope and a control system of a television camera, and an observation mode of the electron microscope, for example, ZOOM or DIF.
F, LOW MAG, etc., the conditions of magnification and camera length, and the mode change and magnification change by communicating the lens excitation strength, TV camera gain, offset, average image brightness, and contrast values. To provide an electron microscope with a TV camera that allows you to observe a TV camera image with optimum brightness at all times.

There are a converging electron lens system capable of irradiating a sample with an electron beam and varying the electron beam irradiation electron beam flow density on the sample surface, and a magnifying lens system capable of enlarging and forming an image of the electron beam transmitted through the sample. The magnification of the image lens system is variable. Further, the converging lens system and the magnifying lens system can be controlled by an arithmetic and control unit.

On the other hand, the magnified electron beam image transmitted through the sample is electrically visualized, for example, by means such as a TV camera. This TV camera controller has an average brightness level of an electrically one-dimensional video signal,
There is an AC component level detection means. Further, the control device of the TV camera is configured to be controllable by the arithmetic control device. The arithmetic and control unit is configured to be communicable with the arithmetic and control unit for controlling the converging lens system and the magnifying lens system.

With such a configuration, controlling the converging lens system and the magnifying lens system according to the average brightness level or the AC component level is a characteristic operation of the present invention.

[0008]

FIG. 1 shows an embodiment of the present invention.

In the figure, an electron beam 2 emitted from an electron beam source 1 irradiates a sample through a converging lens 3 and a converging lens 4. The electron beam transmitted through the sample 5 forms an enlarged image of the sample on the fluorescent plate by the objective lens 6 and the two magnifying lens systems 7 and 8.

A part of the image formed on the fluorescent plate is picked up by the television camera 10 by raising the fluorescent plate.
The image signal displays an enlarged image of the sample on the monitor 18 via the television camera controller 11. This controller is controlled by the arithmetic and control unit 17.

On the other hand, the converging lens, the objective lens, and the magnifying lens are controlled by respective power supplies 12, 13, 14, 15, and 16, but the value of the power supply is another arithmetic control unit 1.
It is controlled by 9.

Further, between the arithmetic and control units 17 and 19,
Communication circuit is stretched.

When an instruction to change the magnification is given from the console 20,
The arithmetic and control unit 19 changes the magnification of the electron microscope by instructing the power supplies 15 and 16 with a lens current corresponding to the lens excitation of the magnifying lens system which is determined in advance according to the magnification.

FIG. 2 shows changes in the electron beam current density on the fluorescent plate when the magnification is changed.

As is apparent from FIG. 2, the change in the current density with respect to the change in the magnification is the square of (magnification), which is an extremely large change. Conventionally, the brightness of the image on the monitor is changed by changing the current that the operator irradiates the sample with a converging lens.
It was adjusted to be almost equal. Since such an operation occurs each time the magnification is changed, the operability of the electron microscope with the television camera is not good.

In the present embodiment, the camera controller monitors the level of the video signal from the camera. FIG. 3 shows changes in the video signal. FIG. 3A shows the change over time of the average level of the video signal. The video signal level is
For example, if the magnification is switched to a high value, as shown in FIG.
Since the current density on the fluorescent screen changes with the square of (magnification), the signal level sharply drops. Such a change in signal level is determined by camera control. When the average level becomes lower than a preset value due to the change in magnification, the arithmetic and control unit communicates a signal level or a signal corresponding thereto to the electron microscope side. The arithmetic and control unit on the electron microscope side controls the convergent lens current so that the electron beam current density increases. If the average level of the video signal of the TV camera falls within the preset value range,
Stop the control of the convergent lens current. With such control,
The manner in which the signal level changes is shown in FIG.

As described above, by adjusting the control current of the converging lens while referring to the average level of the video signal of the television camera, the operator can obtain a television image of almost constant brightness even if the magnification of the electron microscope is changed. Can be observed.

[0018]

According to the present invention, since the output of the television camera can be constantly monitored at a constant brightness, the operator does not need to change the operating conditions of the electron microscope each time the magnification is changed or the mode is changed, and the operability is improved. It can be significantly improved.

[Brief description of drawings]

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

FIG. 2 is an explanatory diagram of a change in brightness on a fluorescent screen due to a change in magnification.

FIG. 3 is an explanatory diagram of a video signal from a television camera.

[Explanation of symbols]

1 ... Electron beam generation source, 2 ... Electron beam, 3, 4: Converging lens,
5 ... sample, 6 ... objective lens, 7, 8 ... magnifying lens, 9 ...
Fluorescent plate, 10 ... TV camera, 11 ... TV camera controller, 12, 13 ... Converging lens power supply, 14 ... Objective lens power supply, 15, 16 ... Enlarging lens power supply, 17 ... TV camera arithmetic and control unit, 18 ... Image monitor, 19 … Electron microscope arithmetic and control unit, 20… Electron microscope console.

Claims (2)

[Claims] 1. A television camera having a function of observing and recording a magnified transmitted image in an electron microscope equipped with a converging lens system for irradiating a sample and a magnifying lens system for magnifying an electron beam transmitted through the sample, and the electron. An electron microscope comprising: a control unit of a microscope and a control unit of the television camera, wherein the electron microscope is controlled on the basis of a DC level of a video signal of the television camera as a criterion. 2. A television camera having a function of observing and recording a magnified transmitted image in an electron microscope equipped with a converging lens system for irradiating a sample and a magnifying lens system for magnifying an electron beam transmitted through the sample, and the electron. An electron microscope comprising: a control unit of a microscope and a control unit of the television camera, wherein the electron microscope is controlled on the basis of an AC level of a video signal of the television camera as a criterion.