JP2005031043A - Measured object elevator mechanism in ct unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve an elevator mechanism for a measured object in a structural aspect to acquire a highly precise three-dimensional CT data image. <P>SOLUTION: In this CT unit, a substrate is arranged between an X-ray irradiation means for the measured object, and an detection means for a transmitted X-ray, a top plate is arranged in an upper side of the substrate opposedly thereto, the substrate and the top plate are connected by a plurality of support columns, and the top plate is elevated while supported by the support columns. A movable rotary table is provided on an upper face of the top plate, a driving motor is fixed to the substrate, a link mechanism for converting its rotation into elevation of the top plate is provided on the substrate, and the measured object is thereby moved accurately along vertical and horizontal directions. As a result, the horizontality of the top plate is surely suppressed within 3 mrad in its tip portion. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a CT apparatus used for nondestructive measurement in the industrial field and the medical field, and more particularly to a lifting mechanism for an object to be measured.

  As a CT device used for nondestructive measurement, a device that rotates the object to be measured, irradiates X-rays at predetermined angles, detects transmitted X-rays, and acquires the internal state in the form of CT image data is practical. It is offered to.

  The CT image data is synthesized and configured as three-dimensional stereoscopic image data. The three-dimensional image data of the measured object obtained here can be displayed as a stereoscopic image on a monitor or the like using an image processing application or the like. Furthermore, the displayed object to be measured can be arbitrarily cut, and the cut surface can be displayed on a monitor or the like. Thus, the internal state can be measured without destroying the object to be measured.

  In order to obtain the CT image data as described above, the CT apparatus is provided with a lifting mechanism for the object to be measured that is movable along all three axes of the X, Y, and Z axes. Further, a mechanism for rotating the object to be measured about the θ axis is also provided. By using such a lifting device, the data obtained by photographing the measurement object for each predetermined rotation angle is synthesized into final three-dimensional image data, so that there is a deviation between the data obtained at each rotation angle. It is required not to occur.

  Specifically, a measurement object lifting mechanism of a conventional CT apparatus will be described with reference to FIG. FIG. 8 is a perspective view showing an object lifting mechanism of the CT apparatus, where 51 is an X-ray generator, 53 is an X-ray detector, and 58 is an object to be measured. An X-ray detector 53 detects X-rays transmitted by irradiating X-rays from the X-ray generator 51 toward the measurement object 58. The X-ray generator 51 and the X-ray detector 53 are fixed to a frame (not shown) of the CT apparatus. This lifting device is controlled so as to be in an optimum position for irradiating X-rays by moving the measurement object 58 in the X, Y, and Z axis directions indicated by arrows. The X-ray detector 53 is provided with a plurality of elements on the detection surface 59 that receive X-rays and convert them into electrical signals and output them. Usually, the optimum position is the place where the central portion of the detection surface 59 coincides with the portion to be measured of the object to be measured.

  Note that the projection of the object to be measured on the detection surface 59 can be enlarged or reduced in accordance with the measurement purpose. When the measurement object 58 is moved in the direction of the X-ray generator 51 on the X axis, the X-rays transmitted through the measurement object 58 are enlarged on the detection surface 59. On the other hand, when it is moved in the direction of the X-ray detector 53, the image is reduced and an optimum CT image can be acquired.

  As described above, the lifting mechanism that controls the measurement position of the measurement object 58 includes the horizontal guide 52, the vertical guide 54, and the holding guide 55 that function as guide rails. The vertical guide 54 is attached to the horizontal guide 52 at a right angle, and the coupling portion thereof can move in the X-axis direction. The holding guide 55 is attached to the vertical guide 54 at a right angle, and its coupling portion can be moved up and down in the Z-axis direction.

  Further, the turntable 57 is attached to the upper side of the holding guide 55 and can move in the Y-axis direction. Further, the measurement object 58 is configured to rotate 360 degrees around the portion to be measured (θ axis). In order to obtain a CT image of the internal state of the measurement object 58, first, a part to be measured of the measurement object 58 is held on the rotary table 56 so as to pass through the θ axis of the rotation center. Then, the measurement object 58 is moved to the optimum position in the X-axis, Y-axis, and Z-axis directions. Further, X-rays are irradiated from the X-ray generator 51 toward the measurement object 58 a plurality of times while the measurement object 58 is rotated. X-rays that have passed through the measurement object 58 are detected by the X-ray detector 53 and output as an electrical signal. Each output signal is combined and finally obtained in the form of three-dimensional solid data.

  On the other hand, there is a mechanism using a link mechanism as a mechanism for raising and lowering the object to be measured. Japanese Patent Application Laid-Open No. 2000-12973 “Elevating Seat Chair” discloses a link mechanism in which two sets of links are crossed in an X shape. In this mechanism, the intersection of the intersecting links is pivotally connected by a connecting rotary shaft, and the lower part of a pair of links is moved horizontally by a drive motor, and the upper part is raised and lowered by changing the angle of each link. It is.

  This link mechanism is characterized in that an isosceles triangle is formed for each of the lower and upper portions of each link crossed in an X shape. With the above configuration, the case attached to the upper part of the link can be moved up and down horizontally while moving the lower part of the pair of links horizontally and rotating each link around the connecting rotation shaft.

With the above configuration, the rotation of the drive motor is converted to the lifting and lowering of the upper lift case via the link mechanism.
JP 2000-12973

  However, in the lifting mechanism characterized by the cantilever structure as in the first conventional example, the holding guide 55 is likely to bend. The deflection causes a shake in the rotation of the rotary table 56. If this blur exceeds an allowable range, the final three-dimensional CT image data configured as a three-dimensional structure is adversely affected, resulting in a problem that measurement accuracy cannot be maintained.

  In order to avoid this, it is necessary to keep the deflection in the gravitational direction within about 3 mrad at the tip of the holding guide 55. There are structural and software measures for this. As a structural measure, there is a means for improving the mechanical strength of each horizontal guide 52, vertical guide 54, and holding guide 55 so that the strain does not exceed an allowable range, and improving the accuracy of each connecting portion. However, the means for obtaining the strength of each component and increasing the accuracy of the connecting portion has the disadvantage that the overall structure becomes large and the processing cost increases. As a software measure, there is a means for correcting the data itself in consideration of the deflection occurring when processing the CT image data, taking into account the detection data. However, correction for each detected CT image data has a drawback that it takes a lot of processing time to obtain final data.

  Further, in the cantilever structure, as shown in FIG. 8, the vertical guide 54 protrudes further upward than the upper end of the rotary table 56. There is a drawback that the rotation range is limited by hitting the part. In order to measure a laterally large object to be measured, it is necessary to increase the distance between the vertical guide 54 and the θ axis, and there is a drawback that the volume of the entire apparatus increases.

  On the other hand, in the X-shaped link mechanism, it is possible to convert the rotational force of the motor into a force in the up-and-down direction while keeping the upper lift case horizontal, and no downward deflection like a cantilever beam occurs. However, in this link mechanism, a fixed gap for rotation, that is, a clearance, is required at the rotating portion and the horizontally moving portion of each link. Even if the accuracy of each component of the link mechanism for the seat chair is increased and the clearance is suppressed as much as possible, the following problems remain. That is, in each part, even if the clearance is slight, the total of all the clearances ultimately affects the level of ascending and descending of the upper lift case. Actually, the total of the lower rotation axis and horizontal movable part of each link, the clearance of the rotation connecting shaft and the upper rotation axis of the link intersection affects the level, and it is difficult to obtain a level of about 3 mrad at the tip. There is.

  The present invention has been made in view of such circumstances, and a main object thereof is to obtain highly accurate three-dimensional CT image data by improving the structure.

  In order to achieve such an object, the present invention has the following configuration. That is, the invention described in claim 1 is a device for irradiating a measurement object with X-rays having transparency, and an X-ray that is disposed opposite to the irradiation means with the measurement object interposed therebetween and transmits the measurement object. In a CT apparatus for acquiring transmission data of the object to be measured, a top plate is disposed between the irradiating means and the detecting means and opposed to the substrate in an upward direction. A plurality of columns that are movably incorporated on either the substrate side or the top plate side between the substrate and the top plate, and a platform that is movable on the top surface of the top plate. And a mechanism for converting the rotation of the drive motor to the elevation of the top plate is provided on the substrate, and the object to be measured is moved vertically and horizontally. .

  According to a second aspect of the present invention, in the measured object lifting mechanism according to the first aspect, the lower part of the pair of links is moved in the horizontal direction to change the inclination angle of the links, thereby The board is moved up and down to move the object to be measured vertically and horizontally.

  According to a third aspect of the present invention, in the measured object lifting mechanism according to the first aspect, two sets of links are arranged so as to cross each other in an X shape, and the movement of the one set of links is performed via a belt. The rotation of the drive motor is transmitted to the set of links and the other link, and the top plate is moved up and down to move the object to be measured vertically and horizontally. .

  According to a fourth aspect of the present invention, in the measured object lifting mechanism according to the first aspect of the present invention, a cylindrical cam having a spiral groove is vertically mounted on the substrate and is engaged with the groove. The upper part of the cam guide provided with is fixed to the top plate, the cylindrical motor is rotated by the drive motor, the cam follower is slid along the groove, and the top plate is moved up and down to move the measurement object up and down. And moving in the horizontal direction.

  According to the measurement object lifting mechanism of the present invention, the top plate and the substrate are held by a plurality of columns, and two of them are pressurized. Since a ball spline shaft is used, the top plate can be moved up and down without shaking. On the other hand, the operation of raising and lowering the top plate is performed by a link mechanism. In other words, the function of pressing up and down the top plate and the function of raising and lowering the top plate share a role. For this reason, the structure is such that the error of the link mechanism hardly affects the level of elevation. These two functions are united to move up and down while maintaining the level of the top plate. As a result, the level of the top plate can be ensured within 3 mrad at the tip without increasing the processing precision of each component. There is an effect that can be pressed.

  According to the first and third aspects of the invention, the elevating mechanism has the same configuration as that of the second aspect, and the level of the top plate can be ensured within 3 mrad as in the second aspect. . Furthermore, since the two sets of links are configured in an X shape as compared with the invention described in claim 2, the object to be measured that is heavier can be moved up and down stably. In other words, there is an effect that it is possible to deal with an object to be measured having a larger weight.

  Further, the invention described in claim 1 and claim 4 employs a cylindrical cam, and a cam follower that rotates smoothly is fitted in a groove provided on a side surface of the cylindrical cam, and the rotation of the drive motor is raised and lowered via the cam guide. It has a configuration that can be converted into a direction. Therefore, the structure for converting the rotation operation into the lifting operation is very simple, and there is an effect that the level of the top plate can be kept within 3 mrad.

  According to each invention described above, there is an effect that CT image data which is finally stable and highly accurate can be obtained. Further, the structure is compact, and there is an effect that the entire apparatus can be reduced in size.

  The objective of acquiring highly accurate measurement data with a simple structure has been realized by making the function of pressing up and down the table top and the function of moving the table up and down separate. In the present embodiment, the error of the link mechanism has a structure that hardly affects the level of elevation, and the top plate has a level of 3 mrad at the tip without increasing the processing precision of each component. .

  FIG. 1 is a perspective view of a lifting mechanism by a link mechanism in Embodiment 1 of the present invention. FIG. 2 is a partially enlarged view of FIG. The lifting mechanism of the first embodiment lifts and lowers the object to be measured using a link mechanism.

  As shown in FIG. 1, the horizontal guide 2 comprised by the slide rail is being fixed to the CT apparatus in the X-axis direction shown by the arrow. A substrate 8 that moves on the horizontal guide 2 in the X-axis direction is attached. The substrate 8 and the top plate 9 are connected by four columns A10, columns B11, columns C12, and columns D13 shown in FIG. The upper part of each column is fixed to the top plate 9, and the lower part is movably inserted into a bush (not shown) having a through hole embedded in the substrate 8 corresponding to the position of the column. At least two diagonals of the pillars, for example, the pillars A10 and C12 are constituted by ball spline shafts. A ball support mechanism is provided on the inner side surface of the bush embedded in the substrate 8 so that the support column A10 and the support column C12 can smoothly move up and down via the ball. In addition, a pressure is applied to the ball so that no side shake occurs when the support A10 and the support C12 are moved up and down. A holding guide 6 composed of a slide rail is fixed to the top surface of the top plate 9, and the turntable 7 is attached to the holding guide 6 so as to be movable in the Y-axis direction. Here, the lower portion of each of the four support columns can be fixed to the substrate 8 and the upper portion can be movably inserted into the top plate 9 by the same configuration as described above.

  As shown in FIG. 1, the turntable 5 is rotatably mounted on a turntable 7. The turntable 5 is configured to rotate while holding the measurement object 4. Further, the DUT 4 is held so that the part to be measured passes through the θ axis, and rotates around that part.

  Next, the link mechanism will be described with reference to FIGS. 2 is a partially enlarged view of FIG. 1, and FIG. 3 is a side view of the lifting mechanism viewed from the X-axis direction. As shown in FIG. 2, the slide rail part 8a and the slide rail part 8b which protruded in the both sides of the longitudinal direction used as the Y-axis direction of the board | substrate 8 are provided. On each rail, a cradle A14 and a cradle B15 are movably attached. The cradle A14 and the cradle B15 are connected to lower portions at both ends in the longitudinal direction of the lower link support 18. Further, a lower rotary shaft 18a is provided on the end surface of the lower link support portion 18 in the longitudinal direction, and is rotatably inserted into a through hole provided in the lower portion of the link A20.

  On the other hand, an upper link support portion 19 is fixed to the lower surface of the top plate 9, and an upper rotary shaft 19a is provided on an end surface in the longitudinal direction of the upper link support portion 19, so that it can rotate in a through hole provided at the upper portion of the link A20. Has been inserted. Similarly, the link B21 disposed on the opposite side of the link A20 is rotatably connected to the lower link support portion 18 and the upper link support portion 19.

  Next, a mechanism for converting motor rotation into vertical movement will be described. A drive motor 17 is mounted on the upper surface of the substrate 8. The drive motor 17 is provided with a long and narrow horizontal shaft 16 for transmitting rotation, and a tip portion thereof is held by a bearing 22 and a root portion thereof is rotatably held by a bearing 23. The horizontal shaft 16 is threaded and is fitted in a screw hole provided in the lower link support 18. As shown in FIG. 3, the lower link support portion 18 moves in the Y-axis direction on the slide rail portion 8a and the slide rail portion 8b while being supported by the cradle A14 and the cradle B15 as the horizontal shaft 16 rotates. It is configured as follows. For example, when the horizontal shaft 16 rotates clockwise, the lower link support portion 18 moves from the bearing 22 side to the bearing 23 side, and when it rotates counterclockwise, it moves in the reverse direction.

  With the above configuration, when the lower link support 18 is located on the bearing 22 side, the top plate 9 is at the lowest position, and when it is moved toward the bearing 23 side, it is at the highest position. The top plate 8 can be moved up and down by the rotation of the drive motor 17 through the link mechanism described above.

  FIG. 4 is a perspective view of an elevating mechanism using a timing belt mechanism in Embodiment 2 of the present invention. FIG. 5 is a side view of the lifting mechanism of the present invention. The same parts or portions as those in the first embodiment will be described using the same reference numerals.

  The raising / lowering mechanism of the second embodiment uses a link mechanism to raise and lower the object to be measured as in the first embodiment. As shown in FIG. 4, the configuration is the same as in the first embodiment, and the substrate 8 that can move in the X-axis direction on the horizontal guide 2 and the top plate 9 that is disposed opposite to the substrate 8 are composed of four columns A10, columns B11, columns. It is connected by C12 and support column D13, and has the same function as in the first embodiment. Further, the holding guide 6, the turntable 7 and the turntable 5 on the top plate 9 are configured in the same manner as in the first embodiment.

  Next, a link mechanism different from the first embodiment will be described. A slide rail portion 8a and a slide rail portion 8b are provided on the Y axis direction of the substrate 8, that is, on both sides in the longitudinal direction. On the slide rail portion 8a, a cradle A14 is attached to the right side and a cradle C29 is movably attached to the left side as viewed in FIG. Similarly, a cradle B15 is mounted on the right side and a cradle D30 is movably mounted on the left side of the slide rail portion 8b. The cradle A14 and the cradle B15 are respectively coupled to the end portion in the longitudinal direction of the lower link support portion 18, and the cradle C29 and the cradle D30 are also coupled to the end portion in the longitudinal direction of the lower link support portion 40, respectively. .

  A lower rotary shaft 18a is provided on the end surface of the lower link support 18 in the longitudinal direction, and is rotatably fitted in a through hole provided in the lower part of the link A20. As shown in FIG. 5, the upper link support 24 is fixed to the left side of the lower surface of the top plate 9, an upper rotation shaft 24 a is provided on the end surface of the upper link support 24 in the longitudinal direction, and the penetration provided in the upper part of the link A 20. The hole is rotatably fitted. A lower rotating shaft 40a is also provided on the end surface of the lower link support portion 40 in the longitudinal direction, and is rotatably fitted in a through hole provided in the lower portion of the link C31.

  Further, as shown in FIG. 5, an upper link support portion 19 is fixed to the right side of the lower surface of the top plate 9, and an upper rotary shaft 19a is provided on an upper end surface of the upper link support portion 19 in the longitudinal direction. It is fitted in a through hole provided in the shaft so as to be rotatable. The link A20 and the link C31 are configured to cross in an X shape as shown in FIG.

  Furthermore, as shown in FIG. 4, a link B21 is arranged on the opposite side of the link A20, a link D32 is arranged on the opposite side of the link C31, and the link D32 on the opposite side is connected to the upper link support part 19 and the lower link support part 40. The link B21 is rotatably fitted to the upper link support portion 24 and the lower link support portion 18.

  Next, a mechanism for converting the rotation of the drive motor 17 into vertical movement will be described. The drive motor 17 is mounted on the upper surface of the substrate 8 as in the first embodiment. The horizontal shaft 16 that transmits the rotation of the drive motor 17 is rotatably supported by a bearing 22 at its tip and a bearing 23 at its root. The horizontal shaft 16 is threaded and is fitted into a screw hole provided in the lower link support 40. When the horizontal shaft 16 rotates, the lower link support portion 40 is configured to move in the Y-axis direction while being supported by the cradle C29 and the cradle D30. For example, when the horizontal shaft 16 rotates to the right, the lower link support portion 40 moves from the bearing 23 side to the bearing 22 side. When it is turned counterclockwise, it moves in the opposite direction. With the above configuration, when the lower link support portion 40 is located on the bearing 22 side, the top plate 9 is at the highest position, and when it is moved toward the bearing 23 side, it is at the lowest position.

  Next, a description will be given of a belt mechanism that links a pair of links A20 and a link B21 disposed on the opposite side thereof and a link C31 and a pair of links D32 disposed on the opposite side thereof.

  As shown in FIG. 4, a pulley support portion 35a is fixed to the longitudinal side surface of the substrate 8 in the vicinity of the column A10, and the timing pulley A33 is rotatably attached to the pulley support portion 35a. Similarly, the pulley support part 35b is fixed to the longitudinal side surface of the substrate 8 in the vicinity of the support B11, and the timing pulley B34 is rotatably attached to the pulley support part 35b. A timing belt 37 is hung on the timing pulley A33 and the timing pulley B34. The receiving belt connecting portion 38 is fixed to the upper portion of the timing belt 37 and in the vicinity of the timing pulley A33, and the timing belt 37 and the lower link support portion 40 are connected. Similarly, a receiving belt connecting portion 38 a is fixed to the lower portion of the timing belt 37 and in the vicinity of the timing pulley 34, and the timing belt 37 and the lower link support portion 18 are connected.

  With the configuration described above, when the horizontal shaft 16 of the drive motor 17 is rotated and the lower link support 40 is moved in the direction opposite to the drive motor 17, that is, in the direction of the bearing 22, the link C31 and the link D32 rise. . At the same time, the lower link support 18 moves in the direction of the drive motor 17 via the timing belt 37, and the link A20 and the link B21 rise. Thus, the top plate 8 can be raised and lowered through the two sets of links by the rotation of the drive motor 17.

  FIG. 6 is a perspective view of an elevating mechanism using a cam mechanism in Embodiment 3 of the present invention. FIG. 7 is a side view of the lifting mechanism of FIG. The same parts or portions as those in the first embodiment will be described using the same reference numerals.

  The lifting mechanism of the third embodiment lifts and lowers an object to be measured using a cam mechanism. As shown in FIG. 6, the substrate 8 and the top plate 9 that can move in the X-axis direction on the horizontal guide 2 are connected by four columns A10, columns B11, columns C12, and columns D13, as in the first embodiment. The same function as in the first embodiment is provided. Further, the holding guide 6, the turntable 7 and the turntable 5 on the top plate 9 are configured in the same manner as in the first embodiment.

  Next, the cam mechanism will be described. As shown in FIG. 6, a cylindrical cam 44 is attached to the center portion of the substrate 8 so as to be rotatable perpendicular to the substrate 8. The cylindrical cam 44 is provided with a groove 48 in a spiral shape with a predetermined width. As shown in FIG. 7, the cam follower 46 is fitted in the groove 48 so that it can move smoothly. A bearing is incorporated in the cam follower 46, and an outer portion in contact with the groove 48 rotates, so that the cam follower 46 moves smoothly along the groove 48. The central axis of the cam follower 46 is fixed to the lower portion of the cam guide 45, and the upper end portion of the cam guide 45 is fixed to the top plate 9 vertically. Similarly, a cam guide 43 is provided on the opposite side of the cam guide 45, and its upper end is fixed vertically to the top plate 9. A cam follower 47 is also attached to the lower portion of the cam guide 43 so that it can move smoothly in the groove 48 in the same manner as the cam follower 46 on the opposite side. Further, a timing pulley 49 is provided below the cylindrical cam 44.

  On the other hand, the drive motor 17 is vertically mounted on the substrate 8, and a timing pulley 41 is fixed to the rotation shaft of the drive motor 17. The timing pulley 41 and the timing pulley 49 of the cylindrical cam 44 are interlocked via a timing belt 42.

  With the above configuration, for example, when the drive motor 17 is rotated so that the timing belt 42 moves leftward in FIG. 7, the cylindrical cam 44 rotates in the same direction via the timing belt 42, and the cam follower 46. The cam follower 47 gradually moves upward along the groove 48 so as to climb the slope. If it is rotated in reverse, it moves down. As a result, the top plate 9 can be raised and lowered via the cam guide 45 and the cam guide 43 by the rotation of the drive motor 17.

  According to the present invention, the level of the mechanism unit that holds the object to be measured can be kept within 3 mrad. Therefore, it can be widely applied not only to a CT apparatus used for nondestructive measurement in the industrial field and the medical field, but also to a measuring apparatus that moves an object to be measured about three axes of X, Y, and Z and requires accuracy thereof.

It is a perspective view of the raising / lowering mechanism by the link mechanism of this invention. Example 1 It is the elements on larger scale of the perspective view of the raising / lowering mechanism by the link mechanism of this invention. Example 1 It is a side view of the raising / lowering mechanism by the link mechanism of this invention. Example 1 It is the elements on larger scale of the perspective view of the raising / lowering mechanism by the timing belt mechanism of this invention. (Example 2) It is a side view of the raising / lowering mechanism by the timing belt mechanism of this invention. (Example 2) It is the elements on larger scale of the perspective view of the raising / lowering mechanism by the cam mechanism of this invention. (Example 3) It is a side view of the raising / lowering mechanism of this invention. (Example 3) It is a figure which is a perspective view of the raising / lowering mechanism of a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 X-ray generator 2 Horizontal guide 3 X-ray detector 4 Object to be measured 5 Rotary table 6 Holding guide 7 Turntable 8 Substrate 9 Top plate 10 Prop A
11 Prop B
12 Prop C
13 Prop D
17 Drive motor 20 Link A
21 Link B
41 Timing pulley 42 Timing belt 43 Cam guide 44 Cylindrical cam 49 Timing pulley

Claims (4)

Means for irradiating the object to be measured with transmissive X-rays, and means for detecting X-rays that are disposed opposite to the means for irradiating the object to be measured and are transmitted through the object to be measured; In a CT apparatus for acquiring transmission data of an object, a substrate is disposed between the irradiation unit and the detection unit, and includes a top plate disposed to face the substrate in an upward direction, and the substrate and the top plate Connected with a plurality of support columns that are movably incorporated between the substrate side or the top plate side between,
A platform is provided on the top surface of the top plate so as to be movable, a drive motor is fixed to the substrate, a mechanism for converting the rotation of the drive motor into raising and lowering the top plate is provided on the substrate, and the object to be measured is And a measuring object lifting mechanism characterized by being moved in the horizontal direction.   2. The measured object raising / lowering mechanism according to claim 1, wherein a lower part of a pair of links is moved in the horizontal direction, and the inclination angle of the link is changed, thereby raising and lowering the measured object by raising and lowering the top plate. An object raising / lowering mechanism that is moved in the horizontal direction.   2. The measured object raising / lowering mechanism according to claim 1, wherein two sets of links are arranged so as to cross each other in an X shape, and the movement of one set of links is transmitted to another link via a belt to rotate the drive motor. Is transmitted to the set of links and the other links, and the object to be measured is moved up and down to move the object to be measured vertically and horizontally.   2. The measured object raising / lowering mechanism according to claim 1, wherein a cylindrical cam having a spiral groove is rotatably mounted on the substrate, and an upper portion of a cam guide having a cam follower engaged with the groove is disposed on the top plate. The cylindrical motor is rotated by the drive motor, the cam follower is slid along the groove, and the top plate is moved up and down to move the object to be measured vertically and horizontally. Measuring object lifting mechanism.