JP2590374B2 - Material testing machine with scanning electron microscope - Google Patents

Description

Description: BACKGROUND OF THE INVENTION A. Field of the Invention The present invention relates to a material testing machine with a scanning electron microscope, and more particularly, to a test specimen synchronized with a repetitive load and having a load axis aligned with a horizontal or vertical axis of a display screen. Is an image of the state.

B. Prior Art For example, a display device (for example, a CRT) that captures a test specimen with a scanning electron microscope while performing a fatigue test using a servo actuator and scans the specimen synchronously with the scanning electron microscope
There is known a fatigue tester with a scanning electron microscope which displays an enlarged image on a display. Generally, an image of a test piece is displayed by aligning the load axis with the horizontal axis of the display screen. However, in this type of apparatus, the test piece is located within the field of view of the scanning electron microscope due to the repeated load acting on the test piece. Vibrates, and an image on a display device such as a CRT vibrates in the horizontal axis direction of the screen which is the load axis direction. Therefore, it has been attempted to apply a load pattern corresponding to a repetitive load applied to a test piece to a deflection coil of a traveling electron microscope to prevent a display image from vibrating.

C. Problems to be Solved by the Invention On the other hand, depending on the matching between the scanning electron microscope and the material testing machine, it is necessary to adjust the focal length of the objective lens of the scanning electron microscope. When the collision position of the electron beam changes, the horizontal axis of the CRT display screen does not always coincide with the load axis of the test piece, and the above-described load pattern is not applied to the deflection coil, FIG.
The image vibrates as indicated by the arrow with a predetermined inclination on the horizontal axis of the screen as shown in FIG. When the signal corresponding to the load pattern is given to the deflection coil as described above, the vibration in the horizontal direction (load axis direction) stops, but the vibration in the vertical direction does not stop, and the image is indicated by an arrow in FIG. Vibrates like
Therefore, conventionally, the deflection coil itself is rotated by a predetermined angle to prevent the image from vibrating in the vertical direction, the adjustment work is complicated, and it is desired to compensate electrically.

Usually, a servo device that controls the actuator drives the actuator according to a command signal of a predetermined load pattern input from a command signal generation circuit, and performs a field-back operation so that the load applied to the test piece has a predetermined load pattern. Although control is performed, the amplitude and phase of the load pattern command signal differs from the actual load applied to the test piece due to the control accuracy and delay time of the servo system. Therefore, when a command signal of the load pattern is given to the deflection coil of the scanning electron microscope to prevent the vibration of the display screen,
There is a problem that the vibration of the display screen cannot be sufficiently suppressed because the actual load of the test piece does not match the command signal.

An object of the present invention is to prevent vertical or horizontal vibration of an image on a display screen without mechanically rotating a deflection coil.

D. Means for Solving the Problems The present invention provides an actuator that loads a test piece, a servo device that controls the actuator to load the test piece in a predetermined load pattern, A scanning electron microscope that obtains a detection output by two-dimensionally scanning the X axis and the Y axis orthogonal thereto, and scans the detection output in synchronization with the scanning of the scanning electron microscope to load the horizontal or vertical axis of the screen. And a display device for displaying an enlarged image with the axes aligned with each other.

The above technical problem is solved by the following configuration.

Θ setting means for setting an arbitrary angle θ with respect to the horizontal or vertical axis of the display screen, cosine calculating means for calculating cosine cos θ of the angle θ, sine calculating means for calculating sine sin θ of θ, and load on the test piece Load detection means for detecting a load to be applied, amplitude signal output means for outputting an amplitude signal representing an amplitude Δa due to a repetitive load generated on the test piece based on the load detected by the load detection means, Δa and cos
a first multiplication unit for obtaining a product of θ and a second multiplication unit for obtaining a product of Δa and sinθ.

The scanning is performed while the electron beam is deflected in the X-axis direction by the product of Δa and cos θ, and the electron beam is deflected in the Y-axis direction by the product of Δa and sin θ.

E. Function In the case where the electron beam is not deflected as in the present invention, the display screen is displayed as shown in FIG. 5 (a) due to the repeated load and the change of the collision position of the electron beam on the test piece by adjusting the focal length. Above, the image vibrates at an angle θ with respect to the horizontal direction of the screen. Therefore, in the present invention, the actual load of the test piece is detected, and the amplitude Δa generated on the test piece by the load is obtained.
The electron beam is deflected in the X-axis direction by the product of cos θ and disappears. The component in the vertical axis direction is deflected in the Y-axis direction by the product of Δa and sin θ and disappears. Therefore, by performing the above-described deflection in the X- and Y-axis directions together with the two-dimensional scanning of the electron beam, an enlarged image of the test piece is displayed on the display screen with the traveling center stationary at the origin of the screen.

F. Embodiment An embodiment will be described with reference to FIGS.

In FIG. 1 showing the overall configuration, reference numeral 10 denotes a scanning electron microscope, which includes an electron gun 11, a scanning deflection coil 12, a synchronous observation deflection coil 15, a detection unit 13, and a test piece chamber 14.
The test piece TP to be gripped by the grippers 21 and 22 is inserted into. An enlarged image of the test piece TP captured by the scanning electron microscope 10 is visualized by a display device, for example, a CRT 51. That is, the scanning of the scanning deflection coil 12 and the CRT 51 is performed by the synchronous scanning circuit 5.
2, the deflection coil 12 scans the test piece TP two-dimensionally with respect to the X-axis and the Y-axis (FIG. 2) using an electron beam, and is emitted from the surface of the test piece TP. The change in the intensity of the detected secondary electrons or reflected electrons is scanned on the CRT 51 in synchronization with the electron beam of the scanning electron microscope 10 to display an enlarged image.

As shown in FIG. 2, the synchronous observation deflection coil 15 includes X-axis deflection coils 15X ₁ and 15X ₂ and Y-axis deflection coils 15Y ₁ and 15Y ₂ , and the X-axis deflection coils 15X ₁ and 15X ₂ X which is the load axis direction
The electron beam is deflected in the axial direction, and the Y-axis direction deflection coils 15Y ₁ and 15Y
₂ deflects the electron beam in the Y-axis direction orthogonal to the direction of the load axis. The control will be described later.

One grip 21 of the fatigue tester is fixed, and the other grip 22 is connected to a servo actuator 25 via a load rod 23 and a load cell 24.
TP is loaded. Hydraulic source 27 for servo actuator 25
Pressure oil is supplied.

The operation panel 31 includes an operation section for inputting a load average value Mean and a load amplitude Δa ′ as shown in FIG. 3 for setting a load pattern for applying a repetitive load, and a scanning speed for selecting slow scan and rapid scan. It has a selection section and an input section for inputting a manual deflection signal for manually controlling the synchronous observation deflection coil 15, and signals from each section are input to the controller 32. The controller 32 sends a signal representing the load average value and the load amplitude to the oscillation circuit 33, and the oscillation circuit 33 adds a control setting signal according to the load pattern of the repetitive load and adds the signal to the matching point.
Supply 34. A load feedback signal is also supplied from the load cell 24 to the combining point 34 via the load amplifier 26, and a deviation signal between the two input signals is supplied to the servo actuator 25 via the amplifier 35.
Loads the test piece TP in the set load pattern.

As shown in FIG. 5 (a), the synchronous observation circuit 60 changes the horizontal axis of the CRT screen on the CRT 51 screen as shown in FIG. 5 (a) with the change of the collision position of the electron beam on the test specimen due to the repeated load and the focal length adjustment. This prevents vibration at a certain angle θ with respect to the direction, and projects the scanning center of the test piece at the origin O on the CRT screen in a stationary manner. In this synchronous observation circuit 60,
The average value signal and the manual setting signal are input from the controller 32, and the detected load signal is input from the load amplifier 26.

 The details of the synchronous observation circuit 60 are shown in FIG.

The θ setting unit 61 sets the angle θ at which the vibration direction of the enlarged image vibrating with the repeated load forms the X axis, and stores an angle θ that is predetermined according to the focal length of the objective lens to be adjusted. . The subtractor 62 subtracts the average value signal output from the controller 32 from the repetition load detection signal output from the load amplifier 26, and forms a signal Δa ′ of only a vibration component from the repetition load component. The gain setting unit 63 multiplies this Δa ′ by a predetermined gain g, and Δa (= Δa ′ × g)
Is calculated. Here, the gain is determined according to the rigidity of the test piece and the like, and is determined so that the distortion amount can be displayed on the display screen. On the other hand, the cosine function generator 64 and the sine function generator 65 provide the angle signal θ output from the setter 61.
The cosine cos θ and the sine sin θ are calculated. The multipliers 66 and 67 calculate c
multiply osθ and sinθ by Δa, respectively Δa · cosθ, Δa · s
Calculate inθ. The switches 68 and 69 close the contact a in the case of automatic setting, and close the contact b in the case of manual setting. In the case of automatic setting, Δa · cosθ is the X axis deflection coil 15X ₁ , 15X
₂ , Δa · sin θ is input to the Y-axis deflection coils 15Y ₁ and 15Y ₂ , respectively. For manual setting, X-axis deflection signal inputted from the operation panel 31, Y-axis deflection signal is input to each coil 15X ₁ ~15Y _2.

That is, as shown in FIG.
For an image that vibrates at an angle θ and amplitude Δa with respect to the axis,
In the X-axis direction, the electron beam is always deflected by Δa · cosθ,
The electron beam is constantly deflected by Δa · sin θ in the Y-axis direction.

On the other hand, the controller 32 supplies a scanning speed setting signal to the synchronous scanning circuit 52, and sets the scanning speed of the electron beam of the scanning electron microscope 10 and the CRT 51. For example, the scanning speed is one screen
Set in the range of 1/60 second to several hundred seconds, set to 1/60 second when displaying a normal image on the CRT 51, and when shooting the display image on the camera CRT 51, the brightness of the image etc. Is set to a time sufficient for sufficient exposure, for example, 100 seconds.

Next, the operation of the control device thus configured will be described. It is assumed that the automatic setting is selected and the switches 68 and 69 are switched to the a contacts.

It is assumed that the servo actuator 25 performs a repetitive fatigue test with a load pattern having a load average value Mean and a load amplitude Δa ′ shown in FIG. Therefore, the controller 32
Sends a signal representing the load mean value Mean and a signal representing the load amplitude Δa ′ to the oscillation circuit 33, and the oscillation circuit 33 adds the waveform signal shown in FIG. At this time, the controller 32 instructs the rapid scanning to the synchronous scanning circuit 52 by the scanning speed setting signal, and the synchronous scanning circuit 52 controls the scanning electron microscope 10 and the CRT 51 so as to scan one screen in 1/60 second. .

The load acting on the test piece is detected by the load cell 24, amplified by the load amplifier 26, and fed back to the combining point 34. A deviation between the waveform signal of the load pattern and the load signal is obtained at the addition point 34, and a signal corresponding to the deviation is input to the servo actuator 25 via the amplifier 35. As a result, the servo actuator 25 is driven, and a load is repeatedly applied to the test piece.

At this time, the detection signal of the load amplifier 26 is
60 is input to a subtractor 62, where the average value Me is calculated from the detected signal.
An is subtracted to calculate a signal Δa ′ representing the amplitude. Then, the gain setting unit 63 calculates Δa, and the multipliers 66 and 67
Δa · cos θ and Δa · sin θ are calculated from the X axis deflection coils 15X ₁ and 15X ₂ and the Y axis deflection coils 15Y ₁ and 15Y, respectively.
Is input to Y _2. As a result, the electron beam is always deflected in the X and Y axis directions so as to collide with the origin O of the observation area of the test piece shown in FIG. This electron beam is applied to the scanning deflection coil 12
As a result, the specimen is also deflected so as to scan the specimen two-dimensionally, so that a still enlarged image of the observation area is displayed on the CRT screen.

In the above, the case where the load axis is matched in the horizontal direction of the display screen has been described. However, in some cases, the load axis may be matched in the vertical direction. In addition, the amplitude is obtained by subtracting the input average value from the actual load. However, the amplitude may be obtained by calculation from the actual load, or the amplitude input from the operation unit may be directly used.

G. Effects of the Invention As described above, according to the present invention, the actual load on the test piece is detected, the amplitude Δa generated on the test piece by the load is determined,
For an image vibrating at an angle θ with respect to the horizontal or vertical direction of the display screen, the electron beam of the electron microscope is Δac
Since scanning is performed while deflected in the X-axis direction by osθ and deflected in the Y-axis direction by Δasinθ, vibration of the enlarged image of the test specimen on the display screen can be accurately suppressed in any direction. Easy images can be obtained.

[Brief description of the drawings]

1 to 4 show one embodiment of the present invention.
FIG. 2 is a block diagram showing the overall schematic configuration, FIG. 2 is a perspective view schematically showing a synchronous observation deflection coil and image vibration on a display screen, FIG. 3 is a graph illustrating a load pattern, and FIG. FIG. 3 is a block diagram showing details of a synchronous observation circuit. FIG. 5 is a diagram for explaining a conventional problem. 10: Scanning Electron Microscope 12: scanning deflection coil 13: detection unit, 14: sample chamber 15,15X _1, 15X _2: X-axis deflection coils 15Y _1, 15Y _2: Y-axis deflection coils 21, 22: gripper, 24: Load cell 25: Servo actuator 26: Load amplifier, 31: Operation panel 32: Controller, 33: Oscillator circuit 51: CRT, 52: Synchronous scanning circuit 60: Synchronous observation circuit, 61: θ setting device 62: Subtractor, 63 : Gain setting unit 64: Cosine function generator, 65: Sine function generator 66,67: Multiplier

Continuation of the front page (56) References JP-A-50-11761 (JP, A) JP-A-63-85422 (JP, A) JP-A-1-197953 (JP, A) JP-A-61-109253 (JP) , A) Japanese Utility Model Showa 57-66854 (JP, U) Japanese Utility Model Showa 63-56555 (JP, U) Japanese Patent Publication No. Sho 62-40815 (JP, B2)

Claims (1)

(57) [Claims] 1. An actuator for loading a test piece, a servo device for controlling the actuator so as to load the test piece in a predetermined load pattern, and an X-axis in a load axis direction orthogonal to the X-axis in a load axis direction. A scanning electron microscope for two-dimensionally scanning the Y axis to obtain a detection output, and scanning the detection output in synchronization with the electron beam scanning of the scanning electron microscope to match the load axis with the horizontal or vertical axis of the screen. A material testing machine equipped with a scanning electron microscope having a display device for displaying an enlarged image by means of: a θ setting means for setting an arbitrary angle θ with respect to a horizontal or vertical axis of the display screen; and a cosine of the angle θ. cosine calculating means for calculating cos θ, sine calculating means for calculating sine sin θ of the θ, load detecting means for detecting a load applied to the test piece,
Amplitude signal output means for outputting an amplitude signal representing an amplitude Δa due to a repetitive load generated on the test piece based on the load detected by the load detection means;
first multiplication means for obtaining a product of θ and Δa and sinθ.
And second multiplication means for obtaining the product of
The electron beam is deflected in the X-axis direction by the product of cos θ, and the Δ
A material testing machine with a scanning electron microscope, wherein the scanning is performed while the electron beam is deflected in the Y-axis direction by the product of a and sin θ.