JP2980252B2 - X-ray diffraction device slit control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a slit control device for adjusting the width of an X-ray width adjusting slit used in an X-ray diffraction apparatus.

[0002]

2. Description of the Related Art Generally, in an X-ray diffractometer, the intensity of diffracted X-rays is measured while changing the incident angle of X-rays on a sample, and the crystal structure of the sample is analyzed based on the measurement result. Further, the line width of the X-ray incident on the sample is determined by a divergence slit arranged between the X-ray source and the sample. In this case, if the X-ray width determined by the divergence slit is determined to be a constant value, when the X-ray incident angle on the sample changes, the area of the X-ray irradiating the sample changes. Would. As described above, when the X-ray irradiation area on the sample changes, the number of crystals of the sample that substantially contributes to diffraction changes, and as a result, a highly accurate measurement result cannot be obtained.

[0003] In order to solve the above problem, X
There have already been proposed some techniques for changing the slit width of the divergent slit in accordance with the change in the line incident angle, thereby always keeping the X-ray irradiation area of the sample at a constant area. For example, JP-A-1-127740 or JP-A-1-102857 discloses a technique for controlling a slit width by opening and closing a slit piece using a parallel four-bar link mechanism.

[0004]

However, in the above-mentioned conventional apparatus, a relatively large torque was required to move the slit piece forming the slit.
Accordingly, there has been a demand for a drive source for operating the parallel four-bar linkage that has a high output torque and that can operate with high accuracy. For example, considering the driving source disclosed in Japanese Patent Application Laid-Open No. Hei 1-172740, a high-torque driving motor is required, and a worm or the like needs to be precisely made of a high-strength material. The present invention has been made in view of the above problems in the conventional device,
It is an object of the present invention to provide a slit control device that can reliably open and close a slit piece even when the output torque of a drive source is small, and that has a very simple structure.

[0005]

In order to achieve the above object, in a slit control device according to the present invention, a parallel four-bar link mechanism for driving a slit piece is rotatable about a fixed pin. And a pair of rotating links opposed to each other and a pair of parallel moving links rotatably connected to the rotating links, and the parallel moving links are further rotated by the rotating links. In response to the above, the robot moves forward or backward in the direction approaching or moving away from the X-ray path. Further, the slits are formed by fixing the pair of slit pieces to the respective translation links so as to extend in a direction orthogonal to the advance / retreat direction of the respective translation links, and at least one slit piece is formed. Linear drive means for pressing the two translation links to move linearly toward the X-ray path;
Resilient means for urging the two translation links to press against the linear drive means.

[0006]

[Operation] A pair of slit pieces forming a slit are:
It extends at right angles to the translation link and thus in the longitudinal direction of the pivot link. As a result, the length from the rotation center of the rotation link to the parallel movement link becomes relatively long. Therefore, when opening and closing the slit pieces, if the parallel movement link is driven linearly to move them in parallel (moving forward and backward with respect to the X-ray path), the slit pieces can be reliably opened and closed with a small torque. It becomes possible.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Before describing a slit control device according to the present invention, an X-ray diffraction device using the slit control device will be briefly described.

FIG. 3 schematically shows an example of the X-ray diffraction apparatus. In the figure, X radiated from X-ray source 1
The line enters the sample 3 after the divergence angle in the horizontal plane is limited by the divergence slit 2. The X-rays incident on the sample 3 are diffracted there, further pass through the anti-scatter slit 4 and the light-receiving slit 5 and enter the X-ray detector 6, where the X-ray intensity is measured. The anti-scatter slit 4 prevents the passage of scattered X-rays other than the diffracted X-rays. Further, the light receiving slit 5 is arranged at the focal point of the diffracted X-rays and allows only the characteristic X-rays to be measured to pass.

The sample 3 is mounted on a columnar sample stage 7 which is arranged to extend in the direction perpendicular to the plane of the drawing. During the X-ray intensity measurement, the sample 3 rotates at a very small rotation speed around an axis ω extending in the direction perpendicular to the paper surface at the center of the diffraction surface of the sample 3. Hereinafter, this rotation is referred to as θ rotation of the sample. A counter arm 9 is fixed to a rotary table 8 arranged coaxially with the sample table 7, and the anti-scatter slit 4, light receiving slit 5 and X
The line detector 6 is fixedly arranged. The turntable 8, and thus the counter arm 9, scans and rotates about the sample rotation axis ω in the same direction as the sample 3 at a rotation speed twice the θ rotation of the sample 3. Hereinafter, this rotation is referred to as 2θ rotation of the counter arm 9.

If the slit width of the diverging slit 2 is set to be constant and invariant when the sample 3 rotates by θ, the irradiation area of the X-ray irradiating the sample 3 changes corresponding to the θ rotation. Variations in the X-ray irradiation area adversely affect the measurement results and need to be prevented. Therefore, the divergence slit 2
The slit width of the divergent slit 2 is changed according to the θ rotation of the sample 3 by the slit control device 10 attached to.

On the other hand, when the sample 3 rotates by θ, the width of the diffracted X-ray diffracted by the sample 3 also changes. Therefore, in order to obtain a highly accurate measurement result, the slit width of the scattering prevention slit 4 and the light receiving slit 5 also needs to be changed according to the θ rotation of the sample 3. Therefore, both slits 4 and 5
Is also provided with a slit control device 10.

Hereinafter, the slit control device 10 will be described in detail. Since the slit control devices 10 attached to the slits 2, 4, and 5 have the same configuration, the slit control device 10 attached to the divergent slit 2 will be described here as an example. FIG. 1 shows a case where the divergent slit 2 and the slit control device 10 are viewed from the direction of arrow I in FIG. The divergent slit 2 is constituted by a pair of slit pieces 11a and 11b facing each other. A slit L is formed by these slit pieces, and X
The line path Q (see FIG. 3) is set in the slit L.

The slit control device 10 includes a base 12 fixed to the machine frame of the X-ray diffraction apparatus and whose position is invariable, two pins 13 provided on the base 12, and rotation of the pins 13. It has two rotatable links 14, 14 attached freely, and two parallel moving links 15, 15 rotatably connected to both ends of the rotatable links 14. Rotating link 14 and translation link 1
Reference numeral 5 denotes a parallel four-bar link mechanism, and one slit piece 11a and one slit piece 11b of the divergent slit 2 are fixed to each of the two translation links 15. In this case, each of the slit pieces 11a and 11b is in a direction orthogonal to the translation link 15, that is, the rotation link 1
4 in the longitudinal direction.

When the rotating links 14 and 14 rotate around the pin 13 in the counterclockwise direction in the figure, the upper translation link 15a connected thereto moves in the direction approaching the X-ray path Q and then moves downward. The link 15b moves parallel and straight away from the X-ray path Q. Thereby, the width of the slit L is reduced. When the rotation links 14, 14 rotate in the counterclockwise direction in the figure, the respective parallel movement links 15a, 15b
Move in the opposite direction to the above case, and the width of the slit L increases.

On the left side of the lower translation link 15b, a linear drive unit 1 for driving the links 14 and 15 is provided.
6 are provided. The linear drive device 16 includes a pulse motor unit 26 that rotates the rotary movement shaft 18 based on a pulse signal S sent from the control device 17 (φ).
And a power converter 19 for converting the rotation (φ) of the rotary movement shaft 18 into a linear motion in the left-right direction in the figure. With this configuration, when an appropriate number of pulse signals S are sent from the control device 17, the rotary movement shaft 18 simultaneously moves straight in the left and right direction in the figure while rotating (φ).

The right end of the rotary movement shaft 18 is in contact with the left end of the lower translation link 15b. Further, the lower parallel link 15b is constantly pressed against the right end of the rotating shaft 18 under a constant pressure by a tension spring 20 stretched between the lower parallel link 15b and the lower end of the base 12. A moving piece 21 is fixedly attached to the left end of the rotary moving shaft 18. As shown in FIG. 2, the moving piece 21 has a generally elongated rectangular shape, and
8 according to the shaft rotation (φ) of 8 as shown by the arrow BB,
At the same time, it also moves in the left-right direction as shown by the arrow A in FIG. 1 according to the axial movement of the rotary movement shaft 18 (left-right direction in FIG. 1). In FIG. 1, at the tip of the moving piece 21, that is, on both sides of the engagement end 21a, two
Two stoppers 22 and 23 are provided in a fixed position. The moving piece engaging end 21a is connected to both stoppers 22,2.
3 can be engaged with, ie, hit against, the stopper 2 when they are so engaged.
The rotation of the moving piece 21 and therefore the rotation (φ) of the rotary moving shaft 18 is prevented by 2 or 23.

When the moving piece engaging end 21a is engaged with the left stopper, that is, the slit closing side stopper 22, and the rotation (.phi.) Of the rotation moving shaft 18 stops, the rotation moving shaft 1 is stopped.
8 comes to the leftmost position. Therefore, due to the spring force of the spring 20, the slit pieces 11a and 11b come closest and the slit L closes to the minimum width. On the other hand, the moving piece engagement end 21
a is the right stopper, that is, the slit opening side stopper 2
3, when the rotary movement shaft 18 comes to the rightmost position and stops, the slit L opens to the maximum width.

In FIG. 1, a detecting end 21b is formed on the left side of the moving piece engaging end 21a. This detection end 21b
When the moving piece engaging end 21a hits the slit closing side stopper 22 and the moving piece 21 stops moving in the left-right direction,
It is detected by the sensor 24. The detection signal from the sensor 24 is sent to the control device 17.

Rather than mechanically stopping the rotation of the moving piece 21 and thus the linear movement of the rotary moving shaft 18 by hitting the moving piece engaging end 21a against the stopper 22, the moving piece detecting end 21b is detected by the sensor 24. At this time, the pulse motor 26 may be stopped to stop the movement of the rotary movement shaft 18.

Hereinafter, the operation of the slit control device having the above configuration will be described. The control device 17 first rotates the rotational movement shaft 18 (φ) to move the rotational movement shaft 18 to the left in the drawing. With the rotation (φ) of the rotary moving shaft 18, the moving piece 21 moves to the left in FIG. 1 while rotating about the rotary moving shaft 18 (BB rotation in FIG. 2), and its engagement end 21a is a slit closing side stopper 22
The linear movement of the rotary movement shaft 18 stops at the point of engagement.
During this time, the lower parallel link 1 is moved by the spring force of the spring 20.
5b translates to the left in the figure, while the upper translation link 15a translates to the right in the figure. As a result, the width of the slit L formed between the slit pieces 11a and 11b has a minimum value. At this time, the moving piece detecting end 21b is detected by the sensor 24, and the control device 17 sets the position as the zero position of the slit L.

In FIG. 1, while the X-ray diffraction measurement is performed, the sample 3 on the sample stage 7 is moved by the sample driving device 25 to θ.
Rotated. At this time, the control device 17 sends a pulse signal S corresponding to the θ rotation of the sample 3 to the pulse motor unit 26 in the linear drive device 16. As a result, the rotational movement shaft 18
It rotates by an angle corresponding to the number of transmitted pulses, and moves straight to the right in the figure by a distance corresponding to the rotation angle. As a result, the lower parallel link 15b moves in the X-ray path Q direction, while the upper parallel link 15a moves in a straight line in the opposite direction, and the width of the slit L is widened.
The X-ray irradiation area on the sample 3 is kept constant.

When the rotary moving shaft 18 advances rightward until the moving piece engaging end 21a engages with the slit opening side stopper 23, the rotation of the rotary moving shaft 18 is performed by the engagement between the engaging end 21a and the stopper 23. Therefore, the rightward movement is prevented. The width of the slit L at this time is the maximum allowable width.

FIG. 4 shows another embodiment of the slit control device according to the present invention. This embodiment is different from the first embodiment shown in FIG. 1 in that another straight driving device 36 is used instead of the straight driving device 16. Link mechanisms 14, 1 driven by the linear drive device 36
5 is exactly the same as that of FIG.
The description of the link mechanism and the like will be omitted.

The rectilinear driving device 36 is in contact with the left end of the lower translation link 15b and is capable of reciprocating rectilinearly in the direction of arrow A, and a rectangular flat plate fixed to the left end of the rectilinear moving shaft 38. And a pressure plate 31 driven by a pulse motor 32 and an arrow C-
And a rotary drive plate 34 that reciprocates as C '. At one position of the outermost peripheral portion of the upper surface of the rotary drive plate 34, a roller 35 as a rotary drive is rotatably provided. It abuts below. Pulse motor 32
Rotates the rotating plate 34 at the same angular velocity θ as the rotational velocity θ of the sample 3 in FIG.

Since this embodiment is constructed as described above, the roller 35 provided on the rotary drive plate 34 rotates at an angular velocity θ with reference to a zero position state indicated by a solid line in FIG. When the roller 35 rotates at an angular velocity θ, the pressure-receiving plate 31 pressed by the roller 35
It moves straight at a speed of W = sin θ, and as a result, the interval between the slit pieces 11a and 11b supported by the upper and lower parallel links 15a and 15b changes at a speed of sin θ. That is, the interval of the slit L changes at a speed of sin θ.

As described with reference to FIG. 3, considering that the sample 3 rotates at the angular velocity of θ, the fact that the interval of the slit L changes at the speed of sin θ in this embodiment means that the X-rays are incident on the sample 3. This means that even when the angle changes, the X-ray irradiation area for the sample 3 can be kept very accurately and constant. In the embodiment shown in FIG. 4, a so-called direct drive system using a pulse motor 34 is adopted as a system for driving the rotary drive plate 34.
Alternatively, a rotary drive mechanism using a worm and a worm wheel or any other drive mechanism may be employed.

Although the present invention has been described with reference to the preferred embodiments, the present invention is not limited to the embodiments. For example, the straight driving means is a driving means based on the pulse signal driving shown in FIG. 1, or the rotary driving plate 3 shown in FIG.
The present invention is not limited to the sin?

[0028]

According to the present invention, the slit piece is attached so as to extend in the direction perpendicular to the parallel movement link, and furthermore, the parallel movement link is driven straight to operate the parallel four-bar link mechanism. Therefore, a drive source having a small output torque can be used as a drive source of the parallel four-bar linkage, which is economical. In addition, since the translation link is always pressed against the linear drive means using an elastic means such as a spring, the vibration of the slit piece can be suppressed to a low level, and the slit opening / closing control can be performed with high accuracy. In addition, since a driving source having a small output torque can be used as a driving source of the translation link, a stopper mechanism for regulating the minimum width and the maximum width of the slit as in the device according to claim 2 can be easily driven. It can also be attached to the source. As a result, a stopper mechanism is not required at all for movable parts such as the slit piece and the link mechanism, and the structure can be further simplified. Further, as in the apparatus according to the third aspect, if the link mechanism is driven linearly by a rotary driving body (roller 35) that rotates at an angular velocity θ equal to the change velocity θ of the X-ray incident angle on the sample. Thus, the X-ray irradiation area on the sample can be maintained more accurately.

[Brief description of the drawings]

FIG. 1 is a side view showing one embodiment of a slit control device according to the present invention.

FIG. 2 is a side view according to arrow II of FIG.

FIG. 3 is a schematic plan view showing an example of an X-ray diffraction device using the slit control device.

FIG. 4 is a side view showing another embodiment of the slit control device according to the present invention.

[Explanation of symbols]

3 Samples 11a, 11
b Slit piece 10 Slit control device 14 Rotating link 15 Parallel movement link 13 Fixed pin 16 Linear drive device 20 Tension spring 18 Rotational movement shaft 21 Moving piece 22, 23 Stopper 38 Linear movement movement shaft 35 Roller (rotary driving body) 34 Rotary drive Plate 32 Pulse motor Q X-ray path L Slit

Continued on the front page (58) Fields surveyed (Int.Cl. ⁶ , DB name) G21K 1/04 G01N 23/207

Claims (3)

(57) [Claims] 1. A slit control device used in an X-ray diffractometer for measuring the intensity of X-ray diffracted by a sample while changing the incident angle of the X-ray incident on the sample at an angular velocity θ, wherein the slit is formed. In a slit control device that drives a pair of slit pieces to be driven by a parallel four-bar link mechanism, the parallel four-bar link mechanism is rotatable around a fixed pin and a pair of rotary links facing each other, A pair of parallel movement links rotatably connected to the rotation links, and the parallel movement links correspond to the rotation of the rotation links, and X
By moving forward or backward in the direction approaching or moving away from the line path, the pair of slit pieces is fixed to each translation link so as to extend in a direction orthogonal to the advance / retreat direction of each translation link. The above slit is formed, and at least one translation link
A slit control device comprising: straight driving means for pressing a linear movement toward a linear path; and elastic means for pressing and biasing the at least one translation link to the straight driving means. 2. The linear drive means rotates in accordance with an electric pulse signal, and simultaneously rotates linearly to press the at least one translation link, and is fixed to the rotary movement axis. A moving piece attached thereto, and a slit closing side stopper member and a slit opening side stopper member which are engageable with the moving piece and are arranged at appropriate intervals along the direction of linear movement of the rotary moving shaft. The slit control device according to claim 1, comprising: 3. The linear driving means includes a linear moving shaft that linearly moves to press at least one translation link, and a rotary driving body that linearly moves the linear moving shaft by rotating. 2. The slit control device according to claim 1, wherein the rotation speed of the rotary driving body is set to be equal to the change speed θ of the incident angle of the X-ray on the sample.