JPS63252348A - Sample image display device - Google Patents

Abstract

PURPOSE:To increase a degree of freedom during CRT displaying and to enlarge an application range of display modes by arbitrarily setting an aspect ratio of a scanning region of electron beams or the like. CONSTITUTION:When amplification degrees of a horizontal scanning signal amplifying circuit 12 and a vertical scanning signal amplifying circuit 13 are controlled independently of each other, an aspect ratio of a scanning region on a sample 18 can be arbitrarily set. Accordingly when electron beams scanned in the same aspect ratio as a display region of a displaying CRT 17, an image of the sample 18 can be displayed all over the screen on the displaying CRT 17 and so a circular pattern on the sample 18 is prevented from being seen an ellipse on the CRT 17. The CRT displaying region is hence used effectively and besides a complicated circuit is not required for the correction of the displaying region on the CRT.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a sample image display device such as a scanning electron microscope.

[Conventional technology]

Conventionally, when displaying a sample image in a device such as a scanning electron microscope, a square area of the sample is scanned with an electron beam, etc.
The signals obtained from this were displayed as a sample image in a square area on a dedicated high-resolution cathode ray tube (hereinafter referred to as CRT). The size of the scanning area on the sample surface could be arbitrarily changed within a certain range according to the observation magnification of the electron microscope, etc., but what could always be observed was a square area on the sample surface.

In addition, due to the limitations of the scanning signal band of the electron beam deflector of a scanning electron microscope or a CRT for display, images can only be obtained by slow scanning.
I have developed a drawback that the image above is difficult to see.

In recent years, with remarkable advances in microelectronics, image signals obtained by scanning with electron beams, etc. are temporarily stored in a frame memory made of semiconductor memory elements, and by reading them out at any time and displaying them on a CRT, the image signals can be read out at any time and displayed on a CRT. Devices such as scanning electron microscopes have been developed that allow easy observation without flickering even in bright places.

However, although most of the CRTs used in these devices have a display area with an aspect ratio of approximately 3:4 and are designed to display a rectangular image area, they do not require a deflector to scan the electron beam, etc. Since the conventional method scans a square area on a sample, an image is also displayed in a square area on a display CRT. This is C for displaying the pattern on the sample.
This is to faithfully reproduce the image on RT without any deviation in aspect ratio.

[Problem that the invention seeks to solve]

As mentioned above, the conventional sample image display method displays an image of a square area in a part of the rectangular display area of the display CRT, which does not effectively utilize the display area of the CRT.
In addition, in order to display the image from the frame memory in the square area of a normally reprinted CRT, the C'RT must be modified to narrow the horizontal display area, or as shown in Figure 3. When sending the image signal read from the frame memory to the display CRT, it is necessary to perform additional operations such as modifying the read clock from the memory and adding appropriate dummy signals before and after the image signal.

The present invention solves the drawbacks of such conventional display devices and
The purpose of this invention is to effectively use the seven display areas and to eliminate the need for a complicated circuit for correcting the display area on the CRT.

[Means for solving problems]

The configuration of the present invention is shown in FIG. 2, taking a scanning electron microscope as an example.

In Figure 1, 1 is an electron gun, 2.4 is an electron beam limiting aperture, 3 is a blanker, 15 is a horizontal deflector, 6 is a vertical deflector, 7 is an objective lens, and 8 is a detector. , 9 is an electron gun control circuit, 10 is a blanking control circuit, 11 is a horizontal and vertical scanning signal generation circuit, 12 is a horizontal scanning signal amplification circuit, 13 is a vertical scanning signal amplification circuit, 14
15 is an objective lens control circuit, 15 is an image signal amplification circuit, and 16 is an objective lens control circuit.
17 is a frame memory, 17 is a CR7 display, and 18 is an observation sample.

Each element and basic configuration are not much different from those of a conventional scanning electron microscope.The feature of the present invention lies in the method of controlling the two scanning signal amplification circuits in 12.13.

That is, as described above, in the conventional scanning electron microscope, the amplification degree of the two scanning signal amplification circuits is kept equal, and the amplification degree of the circuit is changed according to the observation magnification. Therefore, a square area on the sample surface was always scanned with the electron beam.

The present invention solves the drawbacks of the prior art by independently controlling the amplification degrees of the 12 horizontal scanning signal amplification circuits and the 13 vertical scanning signal amplification circuits.

[For production]

According to the present invention, in a device such as a scanning electron microscope, the aspect ratio of the scanning area on a sample can be arbitrarily set by independently controlling the amplification degree of the horizontal and vertical scanning signals of the electron beam. Therefore, the electron beam can be scanned in the same aspect ratio as the display area of the display CRT, and the sample image can be displayed on the display CRT to fill the entire screen. Of course in this case C
Since the aspect ratio of the image pattern on the RT is the same as that of the pattern on the sample, a circular pattern on the sample will not appear as an ellipse on the CRT.

Furthermore, by making the aspect ratio of the electron beam scanning area and the CR7 display area the same, there is no need to modify the display CRT or to perform complicated processing on the image signal read from the frame memory.

〔Example〕

An embodiment of the present invention will be described with reference to FIG.

The electron beam emitted from the electron gun 1 and passing through the aperture 2.4 is deflected horizontally and vertically by the deflector 5.6, and then converged by the objective lens 7 and hits the observation sample 18. At this time, Secondary electrons or reflected electrons generated from the sample enter the detector 8 and are converted into electrical signals. The image signal amplification circuit 15 amplifies the secondary electrons or reflected electrons to the level required for input to the frame memory 16.
Each pixel is converted into a digital quantity by a D converter,
It is stored as a single image.

On the other hand, the horizontal and vertical scanning signal generation circuit 11 generates a sawtooth wave signal 2111a for driving the horizontal and vertical deflectors 5.6 of the electron microscope and an image in the frame memory 16, as shown in FIG. Horizontal and vertical 2 necessary to capture
generates two synchronization signals.

The scanning signal amplification circuits 12 and 13 amplify the sawtooth wave signals from the horizontal and vertical scanning signal generation circuits 11 in accordance with the observation magnification of the electron microscope. Each is amplified independently by a multiplication factor corresponding to the aspect ratio of the display area.

For example, if a CRT with a display area aspect ratio of 3=4 is used, and if the amplification required by the conventional observation magnification is twice as high, then the amplification of the horizontal scanning signal amplification circuit 12 is (4
/3) XK', the amplification degree of the vertical scanning signal amplifier 13 is set to different values so that it becomes K. Then, the horizontal deflector 5 is 4/4
The electron beam is greatly deflected by three times, and as a result, the electron beam scans a rectangular area with an aspect ratio of 3:4 on the sample surface 18.

The signal obtained from the sample 18 is amplified by the image signal amplification circuit 15 as described above, and then stored in the frame memory 16 as a digital quantity. At this time, it is not necessary that the aspect ratio of the number of pixels in the frame memory is 3:4. For example, it is not necessary that the aspect ratio of the number of pixels in the frame memory is 3:4.
When using a frame memory of
It will be compressed to /4 and taken into memory, but CR
When displayed on T, only the horizontal direction is enlarged to 4/3 times, so the magnification returns to the original size and no inconvenience occurs.
The image data from the frame memory is read out at a slow rate to match the synchronization pull-in range of the CRT, and the D/
After being converted to A-transformation, it is sent to the CR7 display 17 together with a synchronizing signal for the CRT, and is displayed as an electron microscope image in the entire display area of the CRT.

〔Effect of the invention〕

As described above, according to the present invention, the aspect ratio of the scanning area of an electron beam or the like can be set arbitrarily, so the degree of freedom in CR7 display is increased, and the range of application of display formats is expanded.

For example, by matching the aspect ratio of the scanning area of an electron beam, etc. to that of the display area of a CRT, an image with the matching aspect ratio can be created by
It can be projected onto the entire display area of the RT, and a general CRT with a horizontally long display area can be used without any modification, and special operations are added to the read clock and image signal when reading images from the frame memory. The advantage is that it is not necessary.

In addition, the scanning area of the electron beam on the sample surface can be set not only to match the aspect ratio of the display CRT, but also to any aspect ratio, so multiple sample images can be unified as shown in Figure 3. This method is very effective even when displaying on multiple screens on one CRT, since it is possible to capture a sample image in a region of the required shape.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of an embodiment of the present invention; FIG. 2 is a diagram showing horizontal and vertical scanning and synchronization signals in the embodiment; FIG. 3 is a diagram showing an application example of the embodiment; FIG. 4 is a diagram showing various conventional signals. [Brief explanation of the drawing]

Claims (2)

[Claims] (1) The sample surface is two-dimensionally scanned with a charged particle beam equivalent to an electron beam, and the signals obtained from the sample are transmitted using a cathode ray tube or the like that is scanned in correspondence with the scanning of the sample surface with the charged particle beam. A device that displays a sample image on a display, which is characterized by displaying an image of an area with an arbitrary aspect ratio on the sample surface by independently controlling the scanning width in the horizontal and vertical directions on the sample surface. sample image display device. (2) The sample image display device according to claim 1, wherein the charged particle beam scans the sample surface in accordance with the aspect ratio of the display area of the display device.