JP2011137781A - Precise electromagnetic wave diffraction measuring apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for correcting deviation of an irradiation position and precisely measuring strain through diffraction, when a position irradiated with electromagnetic waves is deformed by the movement and deformation of an object to be measured, during measurement in measurement of strain by a diffraction method of electromagnetic waves, such as X-rays. <P>SOLUTION: The height of the surface of a test piece is measured by a noncontact distance sensor, and a stage is moved to have the same position, according to a change in the position of the test piece, thus making the irradiation positions with electromagnetic waves identical, even if stress is applied to the test piece during measurement. By providing a mechanism for measuring the surface height of the test piece during irradiation with electromagnetic waves, a mechanism for moving a test piece height position to the initial position, and a mechanism for measuring the diffraction angle of diffraction electromagnetic waves to correct the position irradiated with electromagnetic waves to the same position as the surface of the test piece, measurement errors due to changes in the surface position are avoided and the diffraction angle becomes possible to be accurately measured. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention irradiates an object to be measured (for example, a polycrystalline material) with an electromagnetic wave that is an energy wave such as an X-ray, and measures the diffraction angle of the electromagnetic wave diffracted from the object to be measured. The present invention relates to a measurement technology for measuring constituent element components and strain generated in an object to be measured.

There is an X-ray diffraction method as a method for examining the constituent elements of the object to be measured. When an object to be measured having a regularly aligned atomic arrangement (for example, a crystal structure) or a regular periodic structure of atoms or a molecular arrangement (for example, a periodic structure of a polymer chain) is irradiated with X-rays, the atoms are scattered. The X-rays interfere with each other, and diffracted X-rays are generated in a specific direction according to the interval between the surfaces in which the atomic arrangement is densely arranged (hereinafter referred to as a lattice plane). This X-ray diffraction phenomenon is expressed by the Bragg law, and the diffraction order n (nλ is the wavelength) where the lattice spacing d, the X-ray wavelength λ, the Bragg angle θ, and an integer (eg, 1, 2, 3,...) 2 d sin θ = nλ holds. The lattice spacing has a specific size depending on the type of material and the state of the material, and there are a plurality of lattice planes. When the angle 2θ (twice the Bragg angle) from the X-ray direction irradiating the object to be measured to the direction in which the diffracted X-rays are generated is measured as a diffraction angle, a plurality of diffraction angles are obtained according to the size of the lattice spacing. The peak of the X-ray intensity distribution appears at the position of.

In the above-described measurement of the diffraction angle, when the object to be measured receives a load and expands or contracts, and the lattice spacing d inside the object to be measured changes, the diffraction angle 2θ changes. The amount of deformation (strain) generated in the object to be measured can be measured from the amount of change in the diffraction angle.

In order to accurately measure the constituent elements of the object to be measured and to measure the distortion generated in the object to be measured with high accuracy, the diffraction angle of the diffracted X-ray when the object is irradiated with X-rays is accurately determined. It is necessary to detect well.

When measuring the diffraction angle, an X-ray detector (for example, a scintillation counter) is scanned in the rotational direction around the X-ray irradiation position of the object to be measured to find a direction in which the X-ray intensity distribution shows a peak. The angle in that direction is the diffraction angle.

As shown in FIG. 1, when the X-ray irradiation position on the surface changes due to movement or deformation of the DUT 1 and there is an error 1a in the surface position, and the measurement location of the DUT having unevenness or curvature on the surface At the time of change, a shift in the X-ray irradiation position (for example, a shift in the vertical direction of the diffraction surface) occurs. An error occurs in the measurement of the diffraction angle determined from the diffraction X-ray intensity obtained by scanning of the detector and the peak position on the angle profile 1b, and the measurement is performed with a gap in the lattice plane. This error causes an error in the magnitude of strain.

FIG. 2 shows the deformation state of the surface of the device under test 1c under no load and the surface of the device under test 1d under load and the direction of generation of diffraction X-rays when a compressive load is applied laterally to the device under test. The compression causes expansion in a direction orthogonal to the load direction. Due to the expansion of the object to be measured, the internal lattice spacing increases, so the diffraction angle decreases according to the Bragg law. A change in diffraction angle accompanying the change in the lattice spacing is represented by Δθε. On the other hand, along with the movement of the surface of the object to be measured (upward movement in FIG. 2), the X-rays irradiating the object to be measured are irradiated before the original irradiation surface, and the path of the diffracted X-rays moves in parallel. Assuming that this translation is ΔL, the apparent diffraction angle change ΔθL caused by the translation detected by a detector located at a radius R is approximately measured as ΔθL≈ΔL / R. From this apparent diffraction angle change Δθε + ΔθL, it is possible to approximately estimate Δθε related to strain measurement from geometric conditions, but it is not possible to correct the deviation of the measurement center accompanying the movement of the irradiation position. Thus, an accurate diffraction angle change Δθε cannot be obtained.

In order to reduce the influence of the deviation of the X-ray irradiation position, the X-ray detector removes the diffracted X-rays from the portion where the irradiation position is shifted so that the X-ray detector does not detect the diffraction X-ray from only a specific position within the irradiation range. There is a slit for transmitting the line (for example, a solar slit). The diffraction angle measurement through such a slit is called a parallel beam method (for example, Patent Document 1).

However, when the change in the diffraction angle is small, such as when the strain is very small, the change in the diffraction angle is smaller than the width of the slit, so that the measurement cannot be performed with sufficient accuracy. Further, since the detected diffracted X-ray is limited to a path that can pass through the slit, a sufficient diffracted X-ray intensity for determining the peak position may not be obtained.

In order to align the X-ray irradiation part of the object to be measured with the scanning center position of the detector, a contact with a fixed length is projected from the diffracted X-ray device, and the tip is brought into contact with the object to be measured to confirm the irradiation position. There is a method (hereinafter referred to as a contact method). However, in the contact method, there is a risk of deformation or breakage of an object to be measured due to contact. Moreover, since the contact exists in the X-ray diffraction path, it is necessary to remove the X-ray diffraction path or to secure the diffraction X-ray path by installing a window.

Further, the field-of-view focal point (for example, focus adjustment) of the microscope image can be used for alignment of the surface of the object to be measured. The method based on the focus of the microscope is a non-contact method, so there is little risk of deformation or breakage of the object to be measured, but the irradiated surface is a mirror surface that can be observed with a microscope, and the minute uneven pattern that characterizes the surface (For example, crystal grain boundaries and cracks) need to exist. Furthermore, it is necessary to develop a position control method that manually corrects the position while checking the image during irradiation or incorporates an algorithm based on an advanced image processing method.

As a conventional example of the strain measuring method before the present invention is made, tooth strain measurement is mentioned. Conventionally, as shown in FIG. 3, the diagnosis of tooth meshing is based on the experience of the doctor from the tooth mold 103 when the subject 101 bites a deformable material such as paper, resin, or silicon (for example, the bite paper 102). The upper and lower meshes were evaluated to diagnose the treatment. At present, as shown in FIG. 4, the muscle strength of the jaw masticatory muscle when the subject 101 engages the teeth is detected by the myoelectric potential measuring electrode 104 attached to the skin, and recorded by the electromyogram measuring device 105. EMG measurement to analyze is introduced. This is a method of estimating the muscle strength from the electromyogram obtained by the measurement and determining the state of the teeth per one piece or the like from the non-uniformity of the left and right muscle strength. However, both are indirect measurements, and it is difficult to determine how much load is applied to the teeth at the time of meshing, and it is difficult to provide appropriate treatment data.

By applying the X-ray diffraction method to the patient's teeth, the strain distribution on the tooth surface is clarified, and it becomes possible to diagnose the load state acting on the teeth. However, in the conventional X-ray diffractometer, it is necessary to completely restrain the body so that the patient does not move during measurement in order to eliminate fluctuations in the X-ray irradiation position.
JP 2006-177731 A

The present invention has been made in view of the circumstances described above, and its purpose is a technique that can correct the irradiation position of an electromagnetic wave and measure the correct diffraction angle in accordance with the fluctuation of the surface due to the movement or deformation of the object to be measured. The purpose is to provide. In addition, an object of the present invention is to provide a technique that enables accurate strain measurement without causing deformation or destruction of a measurement target when detecting a position for correction. By examining changes in surface strain that occur when the object to be measured changes physically, it becomes possible to know physical deformation characteristics such as a decrease in strength function.

The invention of claim 1 is an apparatus for irradiating one surface of an object to be measured with electromagnetic waves and measuring a diffracted electromagnetic wave generated from the object to be measured, and irradiating one surface of the object to be measured with an electromagnetic wave having a predetermined intensity. Irradiating means, measuring means for measuring the position change of the electromagnetic wave irradiation position when the surface of the object to be measured moves, and correcting the position change so that the electromagnetic wave irradiation position becomes the same as the object to be measured and the electromagnetic wave An electromagnetic wave diffraction measuring apparatus comprising: a moving unit that moves both or any position of the generation / detection device; and a unit that detects a diffracted electromagnetic wave generated from an electromagnetic wave irradiation position corrected by the moving unit. is there.

The invention of claim 2 is an apparatus for irradiating one surface of the object to be measured with electromagnetic waves and measuring a diffracted electromagnetic wave generated from the object to be measured, and irradiating one surface of the object to be measured with electromagnetic waves of a predetermined light flux. And the measuring device for measuring the position change of the electromagnetic wave irradiation position when the surface of the object to be measured moves, and correcting the position change so that the electromagnetic wave irradiation position becomes the same An electromagnetic wave diffraction measuring apparatus comprising: a moving device that moves both or any position of the generating / detecting device; and a device that detects a diffracted electromagnetic wave generated from an electromagnetic wave irradiation position corrected by the moving means. is there.

The invention according to claim 3 uses a non-contact type distance sensor to measure a change in position of the electromagnetic wave irradiation position, and the electromagnetic diffraction measurement apparatus according to any one of claims 1-2. It is.

The invention according to claim 4 is the electromagnetic wave diffraction measurement apparatus according to claim 1, wherein an actuator using an electric motor is used as the moving means for correcting the position change. is there.

The invention of claim 5 measures the diffraction angle of the diffracted electromagnetic wave by the electromagnetic wave diffraction measuring apparatus according to any one of claims 1 to 2, and determines the strain distribution of industrial materials such as metal, plastic, wood, ceramics, and composite materials. It is an electromagnetic wave diffraction measuring device to measure.

The invention of claim 6 is an electromagnetic wave diffraction measuring apparatus for measuring a diffraction angle of a diffracted electromagnetic wave by the electromagnetic wave diffraction measuring apparatus of any one of claims 1 to 2 and measuring a strain distribution of enamel on a tooth surface.

Invention of Claim 7 is an electromagnetic wave diffraction measuring apparatus which measures the diffraction angle of a diffracted electromagnetic wave with the electromagnetic wave diffraction measuring apparatus of any one of Claims 1-2, and measures distortion distribution of the dentin of a bone and a tooth. .

The invention of claim 8 provides the strain distribution inside the object to be measured by applying a load to the object to be measured from the outside in the strain distribution measurement of any one of claims 5 to 7, and knows the strain characteristics thereof. It is an electromagnetic wave diffraction measuring apparatus characterized by this.

The invention according to claim 9 is the electromagnetic wave diffraction measuring apparatus characterized in that, in the strain distribution measurement according to any one of claims 5 to 7, X-rays are used as the irradiation electromagnetic wave.

A tenth aspect of the present invention is an electromagnetic wave diffraction measuring apparatus using gamma rays as an irradiation electromagnetic wave in the strain distribution measurement according to any one of the fifth to seventh aspects.

An eleventh aspect of the invention is an electromagnetic wave diffraction measuring apparatus characterized in that in the strain distribution measurement of any one of the fifth to seventh aspects, a laser beam is used as an irradiation electromagnetic wave.

According to the configuration of the invention of claim 1, the diffracted electromagnetic wave shifts due to the displacement of the irradiation position due to the movement, deformation, and surface unevenness of the object to be measured, and the apparent distortion is measured by erroneous measurement of the diffraction angle. Although measurement errors occur, accurate measurement is possible by correcting the change in the irradiation position on the surface of the object to be measured during measurement of the diffracted electromagnetic wave.

Further, according to the configuration of the invention of claim 2, the object to be measured or the electromagnetic wave generator and the diffracted wave detector are moved so as to correct the electromagnetic wave irradiation position, the deviation of the diffracted wave generating position is corrected, and the accurate The diffraction electromagnetic wave can be measured.

In addition, according to the apparatus of the third aspect of the present invention, it is possible to detect a diffracted electromagnetic wave that does not disturb the irradiation of the electromagnetic wave by detecting non-destructively the surface change of the object to be measured.

According to the apparatus of the fourth aspect of the present invention, the object to be measured or the electromagnetic wave generator and the diffracted wave detector can be moved by external control for correcting the irradiation position of the object to be measured.

Moreover, according to the method of the invention of Claim 5, it becomes possible to measure correctly the distortion | strain of the industrial material which is a to-be-measured object.

Further, according to the method of the invention of claim 6, it becomes possible to accurately measure the enamel strain on the tooth surface that is the object to be measured.

In addition, according to the method of the invention of claim 7, it is possible to accurately measure the distortion of the dentin of the bone and teeth that are the objects to be measured.

Further, according to the apparatus of the eighth aspect of the invention, it is possible to give strain to the object to be measured and measure the strain characteristics of the object to be measured.

In addition, according to the method of the invention of claim 9, by using X-rays as electromagnetic waves, it is possible to measure strain using the interplanar spacing of the crystal lattice.

Further, according to the method of the invention of claim 10, by using gamma rays as electromagnetic waves, it is possible to perform strain measurement using the interplanar spacing of the crystal lattice.

In addition, according to the method of the invention of claim 11, by using a laser beam as an electromagnetic wave, it is possible to perform strain measurement using a distance between two surfaces larger than the crystal lattice.

Preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The embodiments described below do not limit the contents of the present invention described in the claims. In addition, all of the configurations described below are not necessarily essential requirements of the present invention.

A configuration example of the strain measuring apparatus of the present invention is shown in FIGS. In order to solve the above-described problems, the strain measuring apparatus of the present invention measures the surface of the device under test 1 with the non-contact type distance sensor 3, and the displacement of the measurement position as shown in FIG. This is a mechanism for correcting the movement by moving the measurement object drive base 5. FIG. 6 shows a mechanism for correcting the displacement of the measurement position by moving the X-ray generator 2 and the diffracted X-ray detector 4 by the X-ray apparatus drive base 6, and the measurement error of the diffracted X-ray angle. Is solved by correcting the misalignment.

FIG. 5 shows the configuration of the apparatus according to the present invention. The strain measuring apparatus of the present invention includes an X-ray generator 2 that irradiates one surface of an object 1 with an electromagnetic wave having a predetermined intensity, a position measuring unit 3 that measures a change in the position of the object 1 irradiated with an electromagnetic wave, The device 1 or the electromagnetic wave generator 2 and the means 5 for moving the position of the X-ray detector 4 so that the relative position of the electromagnetic wave to the device under test 1 is the same, and the diffracted electromagnetic wave generated by the detector An apparatus for measuring strain by a diffraction method, comprising an X-ray detection device for detection. When the object to be measured is loaded, the measurement surface of the object to be measured is deformed. Therefore, in the apparatus of the present invention, the position measurement means 3 measures the position change of the electromagnetic wave irradiation position of the object 1 to be measured, and the means 5 for moving the position of the object 1 to be measured causes the relative position of the object 1 to be measured and the electromagnetic wave. To be the same. More specifically, when the deformation of the measurement object is a surface movement due to expansion (FIG. 1), the measurement object 1 is moved downward by means 5 for moving the position of the measurement object 1, thereby increasing the irradiation position. Make the same. Further, as shown in FIG. 6, the relative position of the object to be measured 1 and the electromagnetic wave may be the same by means 6 for moving the electromagnetic wave generation 2 and the position of the X-ray detection device 4.

In the configuration as shown in FIGS. 5 and 6, the non-contact type distance sensor 3 which is a position measuring unit includes a laser beam displacement meter. Since it is a non-contact type, there is little risk of damaging the measured object. Further, there is no influence of shielding the X-ray irradiation path. Examples of the driving platform for the position moving means 5 and 6 include a positioning actuator using a servo motor or a stepping motor. Examples of the object to be measured 1 include industrial materials, biomaterials such as tooth surface enamel and bone and tooth dentin.

FIG. 7 and FIG. 8 show the equipment configuration when measuring teeth. The subject 11 sits on a chair having the posture adjustment mechanism 17 and fixes his head to the drive type head seat actuator 16. The X-ray generator 13 and the diffracted X-ray detector 15 move in an arc shape around the X-ray irradiation position on the scanning guide 12 for angle scanning. The variation of the irradiation position at the time of detecting the diffracted electromagnetic wave is measured by the non-contact distance sensor 14 and sent to the control device 19 as position information. The control device calculates a position correction amount based on this information and outputs the control amount to the head sheet actuator 16 and the scanning guide actuator 18. When the fluctuation amount is large, or when the change is remarkably difficult to measure, a control signal (for example, temporary stop) is transmitted from the control device to the X-ray generation device and the diffraction X-ray detection device. With such a configuration, even when the object to be measured moves (for example, a human), strain can be measured with high accuracy.

(Embodiment 1) Next, as an embodiment utilizing the strain measuring method described above, strain measurement of the extracted tooth enamel will be described. The enamel of the tooth surface layer is 95% or more hydroxyapatite (hereinafter referred to as HAp), and the strength characteristics of the tooth tissue depend on the HAp crystal structure and crystal orientation. In addition, structural properties such as enamel-dentin are greatly involved in tissue load transmission. Such a tooth structure causes local stress concentration and causes damage and destruction of the tooth tissue. If the stress distribution acting on the tooth tissue is known, it will be useful information for diagnostic techniques such as treatment evaluation and defect prediction.

What was shown by FIG. 9 is the outline | summary of the X-ray measuring system of an Example. The displacement of the X-ray irradiation position due to deformation when compressing the dental specimen 1e extracted from a human being, which is the object to be measured, is measured by the displacement meter 3e, and is corrected by the lifting drive base 5e for the object to be measured. Note that the compression load direction in FIG. 9 is the tooth axis direction. In addition, a strain gauge is affixed to the tooth surface in order to confirm deformation at the time of loading, and the tooth specimen 1e is mounted on a compression load jig.

FIG. 10 shows an example of a measurement result of the diffraction X-ray intensity of the tooth enamel described above. As a loading condition, a hydroxyapatite crystal lattice strain was measured when compression 0.200% was given by strain gauge reading. The X-ray irradiation position is different from the strain gauge application position. FIG. 10 shows an example of (004) diffraction pattern change when the compression load is increased. In this example, the lattice strain was increased in the tensile direction (in the direction in which the above-described lattice spacing increased) due to the compressive load, indicating 0.067%. With the apparatus configuration of the present invention, the (004) lattice strain of enamel HAp when a tooth specimen was loaded was measured, and the occurrence of tensile strain in the surface vertical direction was confirmed by the compressive load in the tooth axis direction.

By the above measuring method, strain of tooth enamel can be measured. By executing this system with the system shown in FIGS. 7 and 8, it is possible to diagnose the strain distribution of human teeth.

In addition, this invention is not limited to the said Example, A various deformation | transformation implementation is possible. For example, in this embodiment, the movement of the surface of the object to be measured due to the load was corrected. You may use for the irradiation position determination of the to-be-measured object with an unevenness | corrugation. In addition, even in the case where the stage for fixing the electromagnetic wave generating device and the diffracted electromagnetic wave detecting device fluctuates, it is possible to measure accurate distortion by correcting the relative position of the surface to be measured. Become. In addition, it is possible to construct a similar diffracted wave measuring apparatus not only for X-rays but also for other radiation having a diffraction phenomenon such as neutron rays as electromagnetic waves.

It is explanatory drawing of the diffraction X-ray generation direction change by the to-be-measured object surface position change. It is explanatory drawing of the influence which the surface movement by the to-be-measured object surface position changes has on a diffraction X-ray path. It is explanatory drawing of the diagnostic method of the meshing state by the occlusion paper which is a conventional method. It is explanatory drawing of the diagnostic method of the meshing state by myoelectric potential measurement which is a conventional method. It is explanatory drawing of the mechanism which correct | amends an irradiation position by the movement of a to-be-measured object. It is explanatory drawing of the mechanism which correct | amends an irradiation position by the movement of an X-ray generator and a detection apparatus. It is explanatory drawing which looked at the apparatus which measures a human tooth from the front by the apparatus structure of this invention. It is explanatory drawing which looked at the apparatus which measures a human tooth with the apparatus structure of this invention from the side. It is a structure of the measuring apparatus at the time of making the to-be-measured object into the enamel of the tooth extracted from the human showing Example 1 of this invention. It is the figure which showed the change of the enamel diffraction profile of the loaded tooth | gear with the apparatus structure of this invention.

1 Object to be measured 1a Error in surface position of object to be measured (error in surface position)
1b Diffraction X-ray intensity and angle profile from the object to be measured (Diffraction X-ray intensity and angle profile)
1c Object under load 1d Object under load 1e Tooth sample 2, 13 X-ray generator 3, 14 Non-contact distance sensor 3e Displacement meter 4, 15 Diffracted X-ray detector 5 For object to be measured Driving table 5e Elevating drive table 6 to be measured 6 X-ray device driving table 11 Subject 12 X-ray diffraction device scanning guide (scanning guide)
16 Head sheet actuator 17 Posture adjustment mechanism 18 Scanning guide actuator 19 Control device 101 Test subject (subject) for meshing diagnosis
102 Occlusal paper 103 Teeth mold (teeth mold) generated by biting occlusal paper
104 EMG measurement electrode 105 EMG measurement device

Claims (11)

An apparatus for irradiating one surface of an object to be measured with electromagnetic waves and measuring diffracted electromagnetic waves generated from the object to be measured,
Irradiating means for irradiating one surface of the object to be measured with electromagnetic waves of a predetermined luminous flux;
When the surface of the object to be measured moves, a measuring means for measuring a position change of the electromagnetic wave irradiation position;
Moving means for correcting the position change and moving both the measured object and the electromagnetic wave generation / detection device or the position thereof so that the electromagnetic wave irradiation position is the same;
An electromagnetic wave diffraction measuring apparatus comprising means for detecting a diffracted electromagnetic wave generated from an electromagnetic wave irradiation position corrected by the moving means. An apparatus for irradiating one surface of an object to be measured with electromagnetic waves and measuring diffracted electromagnetic waves generated from the object to be measured,
An irradiation device for irradiating one surface of the object to be measured with electromagnetic waves of a predetermined intensity;
When the surface of the object to be measured moves, a measuring device that measures a change in position of the electromagnetic wave irradiation position;
A moving device that corrects the position change and moves both the object to be measured and the electromagnetic wave generation / detection device or any position so that the electromagnetic wave irradiation position is the same,
An electromagnetic wave diffraction measuring apparatus comprising an apparatus for detecting a diffracted electromagnetic wave generated from an electromagnetic wave irradiation position corrected by the moving means.   The electromagnetic wave diffraction measuring apparatus according to claim 1 or 2, wherein a non-contact type distance sensor is used to measure a position change of the electromagnetic wave irradiation position.   3. The electromagnetic wave diffraction measuring apparatus according to claim 1, wherein an actuator using an electric motor is used as the moving means for correcting the position change.   The electromagnetic wave diffraction measuring apparatus according to claim 1, wherein the object to be measured is an industrial material.   The electromagnetic wave diffraction measuring apparatus according to claim 1, wherein the object is an enamel on the tooth surface and measures the stress distribution on the surface.   The electromagnetic wave diffraction measuring apparatus according to claim 1 or 2, wherein a diffraction angle of the diffracted electromagnetic wave is measured, and a strain distribution of bone and tooth dentin is measured.   The electromagnetic wave diffraction measurement apparatus according to claim 5, wherein a strain distribution is given to the inside of the measurement object by applying a load to the measurement object from the outside, and the distortion characteristic is measured. .   The electromagnetic wave diffraction measuring apparatus according to claim 5, wherein X-rays are used as the irradiation electromagnetic wave.   The electromagnetic wave diffraction measuring apparatus according to claim 5, wherein gamma rays are used as the irradiation electromagnetic wave.   8. The electromagnetic wave diffraction measurement apparatus according to claim 5, wherein a laser beam is used as the irradiation electromagnetic wave.

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