JPH08264148A - Transmission electron microscope - Google Patents

Abstract

PURPOSE: To provide an effective electron microscopic image (an EM image) in any case by using respectively different optimum phosphors for the time when the EM image is observed with eyes and for the time when the EM image is taken by a TV camera. CONSTITUTION: After being made to have the necessary brightness and the spot diameter by a condensing lens 3, an electron beam 2 is radiated to a specimen 4. The beam 2 transmitted through the specimen 4 and containing the information of the specimen 4 is magnified by an objective lens and a projecting lens 6, projected to a green-emitted phosphor 9 on a phosphor plate 7, and an EM image 8 which is optimum for observation with eyes is formed. Meanwhile, in the case transparent plate 14 coated with a phosphor body 12 with wavelength characteristic suitable for spectroscopic sensitivity of a TV camera 16 is employed for an electron optical system, an EM image 13 on the transparent plate 14 can be taken by a camera 10 without heightening the intensity of the electron beam. Consequently, effective electron microscopic images can be obtained in either case; a case an EM image is observed with eyes and a case an EM image is taken by a TV camera and at the same time a specimen is prevented from being damaged owing to no need of increasing the intensity of beam.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to transmission electron microscopes.

[0002]

2. Description of the Related Art An electron microscope image photographed with a TV camera is usually projected on a fluorescent plate coated with a green phosphor of 500 to 550 nm to observe the image. Since it often did not match the spectral sensitivity of, the observation was carried out with a large electron beam current.
This is because the operator usually observed the image of the fluorescent screen when the TV camera was not used, and it was mainly because visual observation was suitable and green was suitable for direct observation.

[0003]

SUMMARY OF THE INVENTION A means for minimizing electron beam damage on a sample to be observed, that is, for efficiently photographing an electron microscope image of a dark fluorescent plate with a TV camera is provided.

[0004]

The spectral sensitivity of a TV camera does not always match the sensitivity characteristics of the human eye. For that purpose, by changing the phosphors for visual observation and for photographing with a TV camera and using different phosphor fluorescent plates, effective electron microscope images can be obtained for both.

[0005]

According to the present invention, the performance of the TV camera can be fully exhibited, the electron beam irradiated to the sample is minimized,
Moreover, the electron beam damage to the sample can be minimized.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the configuration of a conventional transmission electron microscope and a transmission electron microscope equipped with the TV camera device of the present invention.

First, the electron beam 2 emitted from the electron gun and the accelerating tube 1 is irradiated onto the sample 4 after the condenser lens 3 sets an appropriate spot diameter and brightness. The signal of the electron beam 2 transmitted through the sample 4 and containing the information of the sample 4 is transferred to the objective lens 5
Then, the image is enlarged by the projection lens 6 and projected on the phosphor 9 of the phosphor plate 7 to obtain an electron microscope image 8.

Normally, an operator visually observes the electron microscope image 8 of the fluorescent plate 7, but the electron microscope image 8 is T when necessary.
It may be photographed by the V camera 10. At this time, the fluorescent plate 7
The fluorescent substance 8 is rarely made of a material most suitable for the spectral sensitivity of the TV camera 10, and a green fluorescent substance 9 which is easy for an operator to observe is often used. As a result, T
When observing the electron microscope image 8 using the V camera 10,
Due to the difference in sensitivity characteristics between the V camera 10 and the phosphor 9, the electron microscope image 8 with sufficient brightness may be observed dark by visual observation. In such a case, the current value of the electron beam 2 with which the sample 4 is normally irradiated is increased and observed.
In this case, the electron beam 2 is excessively radiated, and the important sample 4 is often damaged.

This occurs because the spectral sensitivity of the TV camera 10 and the wavelength of the phosphor 9 are different, and depending on the wavelength, the electron microscope image 8 may hardly be felt by the TV camera 10. For this purpose, if the spectral sensitivity of the TV camera 10 and the wavelength of the phosphor 9 are used together, the electron microscope image 8 can be efficiently obtained.
Can be taken.

Here, a fluorescent plate 7 coated with a fluorescent substance 9 which emits green light is used for normal observation, and when a TV camera is used, a TV camera device 11 as shown in the figure is used by inserting it inside an electronic optical system. You can try to solve the problem.
It should be noted that the TV camera device 11 is placed entirely outside the electron optical system during normal operator observation, and is set inside the electron optical system only when observing with the TV camera to take an electron microscope image. Further, the mechanical part relating to the insertion / removal of the TV camera device 11 is omitted because it is unnecessary for the description of the present invention.

The structure of the TV camera device 11 is such that the transparent plate 14 coated with the phosphor 12, the mirror 15 and the TV camera 16 are fixed on the base and the whole is taken in and out. Further, the transparent plate 14 is coated with the fluorescent substance 12 having a wavelength characteristic suitable for the spectral sensitivity of the TV camera 16.
As a result, the electron microscope image 13 projected on the phosphor 12 passes through the transmission plate 14, is reflected by the mirror 15, and is reflected by the TV camera 16.
You can shoot with.

Here, when the TV camera 16 is observed, the TV camera device 11 is operated to be taken in and out, but in reality, the TV camera 16 is fixed as shown in the drawing, and the phosphor 12 is used.
It is also a practical means that only the block consisting of the mirror 15 and the mirror 15 can be operated by putting it in and out from the left side of the drawing.

[0013]

[Effects of the Invention] The fluorescent substance of the fluorescent plate that projects the electron microscope image is changed depending on whether the electron microscope image is visually observed or photographed by the TV camera. , T
When taking a picture with a V camera, if a phosphor that matches the spectral sensitivity of the TV camera is used, an effective electron microscope image can be observed with less sample damage.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a transmission electron microscope including a conventional transmission electron microscope and a TV camera device of the present invention.

[Explanation of symbols]

1 ... Electron gun and accelerator tube, 2 ... Electron beam, 3 ... Condenser lens, 4 ... Sample, 5 ... Objective lens, 6 ... Projection lens,
7 ... Phosphor plate, 8, 13 ... Electron microscope image, 9, 12 ... Phosphor, 1
0, 16 ... TV camera, 11 ... TV camera device, 14 ...
Transparent plate, 15 ... Mirror.

Claims (1)

[Claims] 1. A transmission electron microscope equipped with a TV camera for photographing an electron microscope image, wherein the electron microscope image photographed by the TV camera is projected onto a phosphor that matches the spectral sensitivity of the TV camera, and is bright efficiently. A transmission electron microscope characterized by taking an image as an image with minimal electron beam damage to the sample.