KR20080059694A - An appartus for compensating the error of holder for tem use and a method thereof - Google Patents

Abstract

An apparatus for measuring an error of a holder for a TEM(Transmission Electrode Microscope) and a method thereof are provided to increase precision resolution of the holder. An apparatus for measuring an error of a holder for a TEM includes a supporting table, a mirror(20), a laser(30), a detector(40), a rotary shaft, a deceleration gear(50), a motor(60), a motor driver(70), a resolver(80), and a controller(90). The supporting table fixes the holder. The mirror is mounted on a specimen cradle of the holder. The laser radiates a laser beam to the mirror. The detector detects the laser beam reflected from the mirror. The laser and the detector are mounted on the rotary shaft. The deceleration gear rotates the rotary shaft. The motor drives the deceleration gear powered by the motor driver. The resolver is connected between the motor and the motor driver and drives the motor precisely according to a signal transmitted from the motor driver. The controller is connected with the motor driver and performs control of the motor.

Description

Device and method for measuring error of holder for transmission electron microscope {AN APPARTUS FOR COMPENSATING THE ERROR OF HOLDER FOR TEM USE AND A METHOD THEREOF}

1 is a conceptual diagram of a driving method and a holder driving method of a transmission electron microscope (TEM) goniometer

2 is a reference diagram for explaining a method of measuring a tilt angle error of a conventional TEM double tilt holder.

3 is a reference diagram showing the angle of inclination error by angle in the measuring method of FIG.

Figure 4 is a picture of the Gatan Double-tilt Holder (A is an enlarged photograph of the front of the holder, B is a schematic diagram of the driving principle of the sample mounting portion)

Figure 5 is a picture of the Gatan Rotation Holder (A is an enlarged image of the front of the holder, a is a sample mounting portion)

6 is a conceptual diagram of an error measuring apparatus of a holder for a transmission electron microscope according to the present invention.

7 is a block diagram of an error measuring apparatus of a holder for a transmission electron microscope according to an embodiment of the present invention

Figure 8 is a photograph of the error measuring device of the holder for transmission electron microscope according to an embodiment of the present invention

Figure 9 is an exemplary view of a program screen displayed on the error measuring device of the holder for transmission electron microscope according to an embodiment of the present invention

10 is another exemplary view of a program screen displayed on an error measuring apparatus of a holder for a transmission electron microscope according to an embodiment of the present invention.

11 is a flow chart for the error measuring method of the holder for transmission electron microscope according to an embodiment of the present invention.

12 is a graph measuring the inclination angle of the double tilt holder according to an embodiment of the present invention

13 is a graph measuring the rotation angle of the rotation holder according to another embodiment of the present invention (five repetitions)

14 is a graph of an inclination angle measurement error value (a) and a correction value (b) of the double tilt holder according to an embodiment of the present invention.

15 is a graph of a rotation angle measurement error value (a) and a correction value (b) of a rotation holder according to another embodiment of the present invention.

** Description of symbols for the main parts of the drawing **

20 mirror

30: laser 40: detector

50: deceleration gear 60: motor

70: Motor Driver 80: Resolver

90 controller

The present invention relates to error measurement of a holder for a transmission electron microscope, and relates to an error measuring apparatus and method of a holder for a transmission electron microscope that can determine the accuracy of the inclination angle and rotation angle of the holder, and further corrects the error value of the holder itself. will be.

The study using transmission electron microscopy (TEM) depends largely on how the specimens mounted on the sample stage consisting of a goniometer and a holder are manipulated. The sample to be observed with a transmission electron microscope is first mounted in a holder and inserted into a conniometer. On the other hand, in the three-dimensional atomic resolution work, which is emerging as a core transmission electron microscope technique of NT / BT, a double tilt holder is mainly used rather than a rotation holder.

FIG. 1 is a conceptual diagram illustrating a driving method and a holder driving method of a transmission electron microscope (TEM) goniometer. As shown in Fig. 1, the goniometer controls the sample movement in the x, y, and z directions and the sample inclination in the α-axis direction. The holder itself controls the sample rotation in the 360 degree range (rotation holder) or the sample tilt in the β-axis direction (double tilt holder; double-tilt holder). The sample holder for transmission electron microscope should be able to precisely move, incline and rotate the part where the sample to be studied is directly mounted in the direction desired by the researcher in the widest possible range. Specimen tilting by the goniometer is possible up to ± 60 degrees and maintains accuracy of about ± 0.1 degrees, whereas tilting by double tilt holders is possible up to ± 45 degrees and accuracy of about ± 1 degrees To keep it. On the other hand, since the rotation holder adjusts the direction of the specimen by using the rotational drive of the holder and inclines using a goniometer, the specimen can be inclined in a wider area, but the accuracy of holder rotation is low (± 1 degree). Rather, the specimens are far from the axis of rotation, so the amount of specimen movement during rotation is so large that they are almost impossible to use in high magnification operations.

In this regard, the projection method may be used to measure the error of the inclination angle of the holder, Figure 2 is a reference diagram for explaining a method of measuring the tilt angle error of a conventional transmission electron microscope (TEM) double tilt holder, Figure 3 This is a reference diagram showing the angle of inclination error by angle in the measurement method of 2. That is, FIG. 2 illustrates a projection method for measuring an inclination angle error of a double tilt holder, and FIG. 3 illustrates the size A 'that is actually projected on the screen by the projection method and changed by angle, for example. Using an evenly spaced grid, the double tilt holder is inclined at 10 degree intervals from 0 degree to ± 29 degree to take an image projected on the screen. At this time, the interval of the projected grid is converted according to the inclination angle, and the projected size (A ') can be calculated for each angle by using the formula (A' = A × cosβ, β = cos ^-1 (A '/ A)). Can be. If the actual projected size (A ') is projected on the screen for each angle, the double tilt holder can see a large error value at ± 20 °.

However, the above method can easily know the error value without the equipment, there was a problem that can not measure the continuous and fine inclination angle from 0 degrees to ± 29 degrees of the double tilt holder.

For reference, Figure 4 is a picture of the Gatan Double-tilt Holder (A is a magnification of the front of the holder, B is a schematic diagram of the driving principle of the sample mounting portion), Figure 5 is a picture of the Gatan Rotation Holder (A is an enlarged image of the holder front, a is Sample mounting part). In FIG. 4, the double tilt holder is inclined according to the driving of the rotating shaft in the same structure as B. FIG. Such a structure may cause a case where the rotation value and the inclination angle ratio of the rotation shaft are different, and there is a problem that precision is lowered due to the limitation of the volume and weight of the holder itself. Accordingly, there is an urgent need to develop an apparatus capable of determining the accuracy of the inclination angle of the double tilt holder and correcting the error value of the holder.

As described above, the holders on the market are becoming a major problem in the three-dimensional atomic resolution work because the holder has an error value for each unique inclination / rotation angle due to structural defects.

The present invention has been made to solve the problems of the prior art as described above,

It is an object of the present invention to provide an error measuring apparatus and method for a holder for a transmission electron microscope which can grasp the precision of the inclination angle and the rotation angle of the holder and further correct the error value of the holder.

Another object of the present invention is to provide an error measuring apparatus and method for a holder for a transmission electron microscope which can improve the accuracy resolution of the holder.

The present invention relates to error measurement of a holder for a transmission electron microscope, and relates to an error measuring apparatus and method of a holder for a transmission electron microscope that can determine the accuracy of the inclination angle and rotation angle of the holder, and further corrects the error value of the holder itself. will be.

More specifically, the present invention provides an error measuring apparatus for a holder for a transmission electron microscope, the support for fixing the holder for an electron microscope; A reflector mounted on a sample cradle of a holder fixed to the support; A laser beam emitting laser beam to the reflector; A detector for detecting a laser beam reflected by the reflector; A rotating shaft on which the laser and the detector are mounted; A deceleration gear for rotating the rotating shaft; A motor for driving the reduction gear; A motor driver for driving the motor; A resolver connected between the motor and a motor driver to precisely drive the motor by a signal transmitted from the motor driver; A main generator (Process B'd) connected to the motor driver, a pulse generator configured to set a rotation range and a driving range of the motor driver, and a driving range for performing calculation and driving operations; A counter unit for measuring the rotational movement distance of the motor driver as a signal sent from the pulse generator, a display panel for displaying the rotational movement distance, and an input unit for inputting the movement distance and work execution command. A controller for controlling the driving of the motor having a key pad; and a holder for a transmission electron microscope which can grasp the precision of the inclination angle and the rotation angle of the holder and further correct the error value of the holder. An error measuring apparatus and method are disclosed.

According to the present invention, it is possible to grasp the accuracy of the inclination angle and the rotation angle of the holder, further correct the error value of the holder, and as a result, the error measuring device of the holder for a transmission electron microscope which can improve the precision resolution of the holder. And methods.

Hereinafter, exemplary embodiments of an error measuring apparatus and method of a holder for a transmission electron microscope according to the present invention will be described in detail with reference to the accompanying drawings.

6 is a conceptual diagram of an error measuring apparatus of a holder for a transmission electron microscope according to the present invention, Figure 7 is a block diagram of an error measuring apparatus of a holder for a transmission electron microscope according to an embodiment of the present invention.

As shown in FIG. 6, the error measuring apparatus of the holder for a transmission electron microscope according to the present invention is a conceptual diagram of a device for measuring an error of an inclination angle of a double tilt holder. In order to measure continuously, the holder is installed on the center line of the sample, and a laser beam 30 and a detector 40 are attached on a predetermined axis of rotation, and then a laser beam is applied to the sample (the reflector 20). Is measured by measuring the position of the reflected laser beam by the rotational movement pulse of the detector.

As shown in FIG. 7, the configuration of an error measuring apparatus for a holder for a transmission electron microscope according to an exemplary embodiment of the present invention is a configuration diagram necessary for measuring an inclination angle error of a double tilt holder, and is required for measuring an inclination angle of a double tilt holder. The apparatus is largely divided into a motor capable of driving a rotating shaft with a laser and a detector with a constant pulse, a control device for controlling the same, and a device capable of measuring a moving distance of the rotating shaft.

In more detail, in the error measuring apparatus for a holder for a transmission electron microscope according to an embodiment of the present invention, the error measuring apparatus for a holder for a transmission electron microscope,

Support (not shown) for fixing the holder for the electron microscope; A mirror (20) mounted to a sample cradle of a holder fixed to the support; A laser beam (laser) 30 for emitting a laser beam to the reflector; A detector 40 for detecting a laser beam reflected by the reflector; A rotating shaft (not shown) in which the laser and the detector are mounted; A deceleration gear 50 for rotating the rotating shaft; A motor 60 for driving the reduction gear; A motor driver 70 for driving the motor; A resolver 80 connected between the motor and a motor driver to precisely drive the motor by a signal transmitted from the motor driver; A controller (90) connected to the motor driver (70) and performing drive control of the motor; to grasp the precision of the inclination angle and the rotation angle of the holder, and furthermore, its own error value. Can be corrected.

The controller 90 is connected to a motor driver, and a main board unit (Process B'd) for performing calculation and driving operations, a pulse for setting a rotational movement interval of the motor driver and specifying a driving range. A generator, a counter for measuring the rotational movement distance of the motor driver using the signal sent from the pulse generator, a display panel for displaying the rotational movement distance, and the movement distance In addition, an input unit (key pad) for inputting a task execution command is provided to perform driving control of the motor.

In addition, the reflector (mirror) 20 is mounted on the specimen cradle (specimen cradle) is preferably in the form of a disc in the case of a double tilt holder, in the case of a rotation holder is preferably a column shape in which one side is processed in a plane. Therefore, unlike the case of the double tilt holder, the rotation holder is disposed so that the cradle surface of the rotation holder is rotated by 90 degrees with respect to the cradle surface of the double tilt holder to apply the present invention to the configuration of the concept shown in FIG. .

In addition, an optical sensor is used when the detector detects the reflected laser beam, and the optical sensor changes the output voltage according to the amount of incoming laser beam. On the other hand, when the laser beam comes to the position in the center of the optical sensor, the voltage output from the optical sensor is the highest, the position is the reference of the measurement.

In addition, the error measuring device of the holder for a transmission electron microscope according to an embodiment of the present invention to determine the precision of the inclination angle and rotation angle of the holder, and further to correct the self error value of the holder computer, encoder, compensator, etc. It is obvious to those skilled in the art that this is more necessary, so a detailed description thereof will be omitted.

For reference, FIG. 8 is a photograph of an error measuring apparatus of a holder for a transmission electron microscope according to an embodiment of the present invention. The concept of FIG. 7 is developed to measure the inclination angle of the double tilt holder and the rotation angle of the rotation holder. Precision measurement device.

In order to improve the resolution of the rotating shaft equipped with the laser and the detector, the horizontal ball bearing was changed to a vertical ball bearing. For reference, in order to improve the reliability of the β angle, the control may preferably use a close loop control method. On the other hand, by applying the above, after moving the position of the roller bearing (Roller bearing) in the device according to the present invention, by installing a support for fixing the rotation holder on the side to measure the rotation angle of the rotation holder It was.

9 is an exemplary view of a program screen displayed on the error measuring device of the holder for a transmission electron microscope according to an embodiment of the present invention, an exemplary view of a program screen for the tilt angle automatic measuring device for a double tilt holder. If a large amount of time is required to measure the total inclination of the holder, it is preferable to develop a program that automatically performs driving and recording, such as the inclination angle automatic measuring device program for the double tilt holder shown in FIG. In addition, it is preferable to apply the automatic tilt angle measuring program of the double tilt holder to measure and correct the rotation angle of the rotation holder, so that the driving angle of the rotation holder as well as the double tilt holder for the transmission electron microscope can be corrected.

10 is another exemplary view of a program screen displayed on an error measuring device of a holder for a transmission electron microscope according to an embodiment of the present invention, a program displayed on the error measuring device of a double tilt holder and a rotation holder for a transmission electron microscope Another example of the screen. As shown in Fig. 10, the program screen displayed on the error measuring device of the holder for a transmission electron microscope displays a speed index portion for displaying a measurement value of the rotational speed of the reduction gear, and a measurement value for the acceleration during rotation of the reduction gear. Acceleration index part, PEAK voltage part indicating the measured value of the highest voltage output from the optical sensor, current voltage part indicating the measured value of the voltage generated by the optical sensor according to the laser beam, measured value of the rotation angle of the reduction gear The present angle is provided to display, such as to continuously measure the inclination angle of the double-tilt holder or the rotation angle of the rotation holder through the program, and further reduces the drive error by interlocking the corrected value with the drive of the holder. On the other hand, it is desirable to allow the program to set conditions such as rotation step, rotation time, peak voltage value, and repeatability in advance.

11 is a flowchart illustrating an error measuring method of a holder for a transmission electron microscope according to an exemplary embodiment of the present invention. As shown in FIG. 11, the error measuring method of a holder for a transmission electron microscope according to the present invention relates to a method of using an error measuring device of a holder for a transmission electron microscope according to the present invention, wherein the reflector is mounted on the sample cradle of the holder. Inserting (S100); Adjusting and fixing the holder such that the laser beam of the laser machine is at the center of the reflector mounted on the sample cradle (S200); Tilting the sample cradle portion of the holder (S300); Rotating the detector at regular intervals attached to the rotating shaft (S400); Detecting a laser beam reflected by the reflector (S500); And converting the rotation angle of the rotation shaft (S600).

The method may further include obtaining an error value corresponding to a specific angle from a result of converting the rotation angle of the rotation shaft.

12 is a graph measuring the inclination angle of the double tilt holder according to an embodiment of the present invention. As shown in FIG. 12, the graph of measuring the tilt angle of the double tilt holder according to the exemplary embodiment is a graph of measuring the tilt angle of the double tilt holder using the measuring apparatus and method according to the present invention. As a result of repeated measurement of the tilt angle of the double tilt holder, a different result was measured every time, and the horizontal ball bearing mounted to improve the resolution of the rotating shaft with the laser and the detector was changed to a vertical ball bearing. As a result of the measurement, the error value decreased from ± 0.024 ° to ± 0.013 °.

13 is a graph (five repetitions) of measuring the rotation angle of the rotation holder according to another embodiment of the present invention. As shown in FIG. 13, the graph measuring the rotation angle of the rotation holder according to another embodiment of the present invention is a graph obtained by repeatedly measuring the rotation angle of the rotation holder using the measuring apparatus and method according to the present invention. The average error of the holder's rotation angle was ± 0.1 °, indicating a regular error.

On the other hand, it is possible to correct the error value of the holder based on the measurement results of FIGS. 12 and 13, the correction of the error value is the reverse value for the error value corresponding to a specific angle obtained from the measurement result You can use the principle of sending and canceling each other.

14 is a graph of a tilt angle measurement error value (a) and a correction value (b) of the double tilt holder according to an embodiment of the present invention. As shown in FIG. 14, when the double tilt holder is measured by correcting the correction value (b) with respect to the tilt angle measurement error value (a) of the double tilt holder, the error of the tilt angle is ± 0.05 ° at ± 0.15 ° before correction. Was reduced.

15 is a graph of a rotation angle measurement error value (a) and a correction value (b) of the rotation holder according to another embodiment of the present invention. The graph of the rotation angle measurement error value (a) and the correction value (b) of the rotation holder of FIG. 15 is a graph showing the correction value (b) based on the average error value (a) of the rotation angle of the rotation holder of FIG. to be.

As a result of the experiment, it was found that by using the error measuring apparatus and method of the holder for a transmission electron microscope according to the present invention, the resolution of the holder can be improved from ± 1 ° to ± 0.01.

The configuration and operation as described above are not limited to the claims of the present invention as an embodiment, and various changes and modifications are possible within the scope of not changing the technical spirit of the present invention. It is obvious to those who are engaged.

According to the present invention as described above, there is provided an error measuring apparatus and method of a holder for a transmission electron microscope that can grasp the precision of the inclination angle and rotation angle of the holder, and further can correct the error value of the holder.

As a result, the present invention provides an error measuring apparatus and method for a holder for a transmission electron microscope that can improve the precision resolution of the holder.

Claims (7)

In the error measuring device of the holder for transmission electron microscope, Support (not shown) for fixing the holder for the electron microscope; A mirror (20) mounted to a sample cradle of a holder fixed to the support; A laser beam (laser) 30 for emitting a laser beam to the reflector; A detector 40 for detecting a laser beam reflected by the reflector; A rotating shaft (not shown) in which the laser and the detector are mounted; A deceleration gear 50 for rotating the rotating shaft; A motor 60 for driving the reduction gear; A motor driver 70 for driving the motor; A resolver 80 connected between the motor and a motor driver to precisely drive the motor by a signal transmitted from the motor driver; The controller (90) is connected to the motor driver (70), and performs a drive control of the motor; device for measuring the error of the holder for a transmission electron microscope, characterized in that it comprises a The method of claim 1, The controller (90), Connected to the motor driver, the main board unit (Process B'd) for performing calculation and driving tasks, a pulse generator for setting the rotational movement interval of the motor driver and designating the driving range, and the pulse A counter unit for measuring the rotational movement distance of the motor driver as a signal sent from the generator, a display panel for displaying the rotational movement distance, and an input unit for inputting the movement distance and work execution command ( Device for measuring the error of a holder for a transmission electron microscope, characterized in that it comprises a key pad) The method of claim 1, The reflector (mirror) 20 is an error measuring device of a holder for a transmission electron microscope, characterized in that in the case of a double-tild holder of the disk shape The method of claim 1, In the case of the rotation holder, the mirror 20 is an error measuring device of a holder for a transmission electron microscope, characterized in that one side is a column shape processed into a plane. The method of claim 1, Error measuring device of a holder for a transmission electron microscope, characterized in that the position where the optical sensor output voltage at the detector becomes the highest reference Support (not shown) for fixing the holder for the electron microscope; A mirror (20) mounted to a sample cradle of a holder fixed to the support; A laser beam (laser) 30 for emitting a laser beam to the reflector; A detector 40 for detecting a laser beam reflected by the reflector; A rotating shaft (not shown) in which the laser and the detector are mounted; A deceleration gear 50 for rotating the rotating shaft; A motor 60 for driving the reduction gear; A motor driver 70 for driving the motor; A resolver 80 connected between the motor and a motor driver to precisely drive the motor by a signal transmitted from the motor driver; In the method using an error measuring device of a holder for a transmission electron microscope connected to the motor driver (70), the controller (90) for performing the drive control of the motor; Inserting the reflector into the sample cradle of the holder (S100); Adjusting and fixing the holder such that the laser beam of the laser machine is at the center of the reflector mounted on the sample cradle (S200); Tilting the sample cradle portion of the holder (S300); Rotating the detector at regular intervals attached to the rotating shaft (S400); Detecting a laser beam reflected by the reflector (S500); Converting the rotation angle of the rotating shaft (S600); error measuring method of the holder for a transmission electron microscope, characterized in that comprises a The method of claim 6, The error measuring method of the holder for a transmission electron microscope, characterized in that further comprising the step of obtaining an error value corresponding to a specific angle from the rotation angle conversion result of the rotating shaft.

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