JP4540505B2 - 3D shape measuring device - Google Patents

Description

  The present invention is a three-dimensional shape capable of measuring position information, such as height information from a reference position, of an object to be measured such as an optical component or a mold, for example, with ultra-high accuracy on the order of nanometers, for example. It relates to a measuring device.

For example, the use of a three-dimensional shape measuring apparatus is widely known as a device for measuring the surface shape of an optical component such as a lens or an aspherical object such as a mold with high accuracy on the order of nanometers.
In general, a three-dimensional shape measuring apparatus having a measurement device for a measurement object is configured so that the measurement device for the measurement object is brought into contact with the measurement object, and the measurement for the measurement object is performed so that the contact force is substantially constant. While controlling the Z-direction position of the measuring instrument, the measuring instrument for the object to be measured is moved along the measuring surface of the object to be measured, and based on the positional relationship between the measuring instrument for the object to be measured and the reference surface, The surface shape of the measurement surface is measured and calculated. As one of such measuring devices, a three-dimensional shape measuring device using a laser length measuring device and a reference plane mirror is known, and the measuring device for the measuring object and the operation of the measuring object when performing the measurement The methods are roughly divided into the following two methods.

  The first method is a method in which the object to be measured is fixed and the measuring instrument for the object to be measured is moved in all directions of the X axis, the Y axis, and the Z axis. A representative example will be described with reference to FIG. (For example, refer to Patent Document 1.)

  FIG. 8 shows the structure of a conventional three-dimensional shape measuring apparatus, and the conventional three-dimensional shape measuring apparatus 50 fixes the object 1 to be measured and measures the shape of the object 1 to be measured. Is a device for measuring the shape of the measurement surface 1a of the DUT 1 by moving the device 2 in all directions of the X-axis, Y-axis, and Z-axis, and is provided on the front surface of the body 3 with a cover 3 covering the device. Door 4, a stone surface plate 5 on which various mechanism members are placed, and a gantry 34 on which the stone surface plate 5 is placed. A base plate 19 fixed to the stone surface plate 5 is installed on the stone surface plate 5, an XY-table 35 is installed on the base plate 19, and a mounting panel 37 is installed on the XY-table 35. Installed. Here, the XY-table 35 is installed on the base plate 19 and can be moved by sliding in the Y-axis direction, and the X-axis direction installed on the Y-table 21 and orthogonal to the Y-axis direction. And an X-table 24 that can slide and move. The mounting panel 37 includes a laser beam generator 10, a measurement mechanism 12 having optical components for guiding, branching, and detecting the laser beam 14 generated from the laser beam generator 10, and a Z table 18 that is movable in the Z direction. And a bracket 36 on which is installed. Although not shown, the measurement mechanism 12 uses four laser beams 14 generated from the laser beam generator 10 in order to obtain respective coordinate values in the X, Y, and Z axis directions of measurement points on the measurement surface 1a. An optical system that divides the light into two and guides each of the optical systems; and a detector that obtains the coordinate values based on the laser light guided by the optical system. Also, below the Z table 18, the measuring object measuring device 2 having a stylus that contacts the measurement surface 1a and for obtaining the position coordinates in the Z-axis direction of the measurement point on the measurement surface 1a is installed. . Above the Z table 18, a reference plate 7 having a reference surface 7a on which one of the four branched laser beams 14 is irradiated is a bridge-like member (not shown) installed on the stone surface plate 5. ). The reference plate 7 is irradiated with the laser beam 14 in order to obtain information for compensating for the amount of displacement in the Z-axis direction of the XY-table 35 itself that moves when measuring the shape of the DUT 1.

The measurement operation of the DUT 1 by the conventional three-dimensional shape measuring apparatus 50 configured as described above is performed as follows.
The stylus provided in the measurement object measuring instrument 2 contacts the measurement surface 1a of the measurement object 1, and the XY-table 35 moves in an arbitrary direction on the XY plane. At this time, the position of the Z table 18 is controlled in the Z direction so that the contact force between the stylus and the measurement surface 1a is substantially constant. Further, the stylus is moved along the measurement surface 1 a by the movement of the XY-table 35, and the laser beam 14 emitted from the laser beam generator 10 is detected by the measurement mechanism 12. And the reference surface 7a in the X, Y, and Z axis directions are obtained, and the surface shape of the measurement surface 1a is calculated and measured from the positional relationship.

  Next, as a second method, there is a method in which the object to be measured is moved in the X-axis and Y-axis directions, and the measuring instrument for the object to be measured is moved in the Z-axis direction. A typical example will be described with reference to FIGS. 9 to 13 (see, for example, Patent Document 2). 9 to 13, components having the same functions as those shown in FIG. 8 are denoted by the same reference numerals, and description thereof is omitted.

  FIG. 9 is a front view of another type of conventional three-dimensional shape measuring apparatus 60, and FIG. 10 is a cross-sectional view taken along line EE shown in FIG. In addition, illustration of the Y-axis direction sliding part is abbreviate | omitted in FIG. The three-dimensional shape measuring device 60 is a device in which the device under test 1 moves in the X-axis and Y-axis directions, and the device for measuring device 2 moves in the Z-axis direction. The door 4 can be freely opened and closed, the stone surface plate 5 on which various mechanism members are placed, and the mount 34 on which the stone surface plate 5 is placed.

  11 is a detailed cross-sectional view of the XY-table 38 at the EE portion shown in FIG. 9, and FIG. 12 is a detailed cross-sectional view of the XY-table 38 at the FF portion shown in FIG. In FIG. 11, the Y-axis direction sliding portion is not shown, and in FIG. 12, the X-axis direction sliding portion is not shown. 11 and 12, the XY-table 38 is installed on the stone surface plate 5, the base plate 19 fixed to the stone surface plate 5, the Y-table 21, the X-table 24, and the holding table 8. And have. The Y-table 21 is slidable and movable in the Y-axis direction on the base plate 19 via a roller bearing 39, and the X-table 24 is Y-axis on the Y-table 21 via a roller bearing 40. The holding table 8 is attached with a reference plate 7 having a reference surface 7a on the back side, and the object 1 to be measured is placed on the front side. And is placed on the X-table 24.

  Further, since the three-dimensional shape measuring apparatus 60 uses the roller bearing 40, it is necessary to increase the thickness of the tables 21 and 24 in order to ensure the rigidity of the tables 21 and 24. Therefore, it is difficult to form a space inside the XY-table 38, and the drive mechanisms for the tables 21 and 24 cannot be installed inside the XY-table 38. Therefore, the Y-table 21 and the X-table 24 are moved in the Y-axis direction and the X-axis direction by a ball screw mechanism 46 having a stepping motor 45 installed outside the XY-table 38, as shown in FIG. Has been done. In order to prevent the vibration of the ball screw 46a constituting the ball screw mechanism 46 from being directly transmitted to the tables 21 and 24, the nut portion 46b that engages with the ball screw 46a is connected to each table via a plate spring 47 that functions as a vibration absorbing member. 21 and 24.

  In the three-dimensional shape measuring apparatus 50 shown in FIG. 8, all of the Z table 18 having the laser beam generator 10, the measuring mechanism 12, and the measuring instrument 2 for the object to be measured are formed on the XY-table 35 that generates undulations during movement. Since it is installed, the reference plate 7 used for the measurement of the swell is installed on the apparatus main body which is fixed and does not displace with respect to the measurement. On the other hand, in the three-dimensional shape measuring apparatus 60 shown in FIG. 9 and the like, the laser beam generator 10, the measuring mechanism 12, and the Z table 18 are installed on the stone surface plate 5 that is not displaced with respect to measurement. The reference plate 7 is placed on the resulting XY-table 38.

  As shown in FIG. 10, on the stone surface plate 5, the portal member 41 on which the Z-table 18 movable in the Z-axis direction is installed, and the laser beam generator 10 and the laser beam 14 are guided, branched, A mounting panel 42 equipped with a measuring mechanism 12 to be detected is placed. Further, the measuring object measuring device 2 is installed below the Z-table 18.

The measurement operation of the DUT 1 by the conventional three-dimensional shape measuring apparatus 60 configured as described above is performed as follows.
The stylus of the measurement object measuring instrument 2 is brought into contact with the measurement surface 1a of the measurement object 1, and the XY-table 38 is moved in an arbitrary direction on the XY plane. At this time, the reference plate 7 provided on the back surface of the holding table 8 on the XY-table 38 and forming the reference surface 7a also moves simultaneously. Further, the position of the Z-table 18 is controlled in the Z direction so that the contact force between the stylus of the measuring instrument 2 to be measured and the measurement surface 1a becomes substantially constant. Based on the position control, the amount of displacement of the measurement surface 1a in the Z-axis direction is measured, and further, the laser light 14 emitted from the laser light generator 10 moves along with the movement of the DUT 1 in the XY axis direction. Based on the detection result by the measurement mechanism 12, the surface shape of the DUT 1 is calculated and measured.
Japanese Patent Laid-Open No. 5-87540 JP-A-10-170243

  However, in the above-described conventional three-dimensional shape measuring apparatus 50, as is apparent from FIG. 8, the Z-table 18 for driving the measuring object measuring device 2 in the Z-axis direction is located at the front portion from the XY-table 35. It protrudes greatly toward the measurement space. Therefore, in order to move the X-axis, Y-axis, and Z-axis in all directions with high accuracy, it is necessary to improve the rigidity of the XY-table 35, and the XY-table 35 must be enlarged. As a result, the entire apparatus becomes large. In addition, the laser beam may fluctuate due to the fluctuation of the air due to the rising air flow due to the heat generated from the laser beam generator 10, which may hinder the measurement with higher accuracy.

  In the above-described conventional three-dimensional shape measuring apparatus 60, the object to be measured 2 and the Z-table 18 are moved to the XY by holding the object to be measured 1 on the holding table 8 on the XY-table 38. -It can be separated from the table 38, the problem in the three-dimensional shape measuring apparatus 50 is solved, and the entire apparatus can be reduced in size. However, since the reflecting mirrors 15 and 16 are provided below the stone surface plate 5 in order to guide the laser beam 14 to the reference plate 7, a space for installing the reflecting mirror is ensured between the stone surface plate 5. The gantry 34 is required, which hinders the downsizing of the entire apparatus, particularly the lower size. In addition, ascending air current is generated through the hole 5a through which the laser beam 14 provided on the stone surface plate 5 passes, and the laser beam 14 fluctuates, which may hinder higher-precision measurement as in the case of the three-dimensional shape measuring apparatus 50. Absent.

  Further, the reflection mirrors 15 and 16 installed below the stone surface plate 5 irradiate the reference plate 7 provided on the back surface of the holding table 8 of the XY-table 38 with the laser beam 14 and reflect it by the reference plate 7. It is necessary to accurately return the laser light to the measurement mechanism 12 provided with the detection unit. Therefore, the angle adjustment of the reflection mirrors 15 and 16 needs to be performed with high accuracy, but as is apparent from the drawing, the adjustment work place is narrow and there is room for improvement in the adjustment workability.

  In addition, in the three-dimensional shape measuring apparatus 60, the structure which implement | achieves size reduction of an apparatus by installing the reflective mirrors 15 and 16 on the stone surface plate 5 is also considered. In order to adopt this configuration, it is necessary to secure an installation space 44 for the reflection mirror 16 with an angle adjustment mechanism in the inner portion of the Y-table 21 below the reference plate 7 on the base plate 19. However, the XY-table 38 uses a roller bearing 40 that suppresses rattling of a bearing portion that becomes a sliding portion by applying pressure in the horizontal direction, that is, the X-axis and Y-axis directions. Therefore, the base plate 19 and the Y-table 21 are required to have such rigidity that the high flatness of the holding base 8 is not deteriorated by the pressure inside, and the thickness of the base plate 19 and the Y-table 21 in the horizontal direction is as follows. It must be thick. Therefore, it is difficult to secure the installation space 44 for reasons of measurement accuracy.

Further, in the conventional three-dimensional shape measuring apparatuses 50 and 60, the laser light generating apparatus 10 and the measuring mechanism 12 for guiding, branching, and detecting the laser light are installed on the same mounting panel. The mounting panel itself may be thermally deformed due to heat generated from the light, or the measurement mechanism 12 on the mounting panel may be thermally deformed, resulting in an optical axis misalignment of the laser beam and hindering more accurate measurement. There was also sex.
The present invention has been made to improve the above-described problems, and an object of the present invention is to provide a three-dimensional shape measuring apparatus that is small in size with high measurement accuracy.

In order to achieve the above object, the present invention is configured as follows.
That is, the three-dimensional shape measuring apparatus according to the first aspect of the present invention includes a laser light generator that generates laser light,
An optical system for branching the laser beam into a plurality of parts;
A measurement table installed on a surface plate and moving in a first direction and a second direction orthogonal to each other;
A detector that measures the shape of the measurement surface of the object to be measured placed on the measurement table using a part of the branched laser beam;
A reference plate disposed on the surface of the measurement table opposite to the surface on which the object to be measured is placed;
A reference plate optical system that is provided in the optical system and guides another part of the branched laser light to the reference plate;
A reflection mirror facing the reference plate of the optical system for the reference plate is disposed in an inner space between the surface plate and the measurement table ;
The measurement table includes a first sliding mechanism for sliding the measurement table in the first direction, and a second sliding mechanism for sliding in the second direction,
The first sliding mechanism is engaged with two first guide rails laid in parallel to form a gap through which the laser beam passes to the reference plate, and the first guide rails, respectively. A first pedestal member that slides along one guide rail,
The second sliding mechanism is engaged with two second guide rails laid in parallel to each other perpendicular to the first guide rail, and on each second guide rail, along the second guide rail. A second base member that slides;
It is characterized by that.

  An inclination angle adjusting mechanism that extends between the two first guide rails laid in parallel from the outside of the measurement table to the inside space and adjusts the inclination angle of the reflection mirror from the outside of the measurement table. May be further provided.

  Moreover, you may comprise so that the division member divided | segmented into the 1st area | region which has the said measurement table, and the 2nd area | region which has the said laser beam generation part may be further provided on the said surface plate.

The three-dimensional shape measuring apparatus can also be configured as follows.
An XY-table that is installed on a surface plate and moves in the X-axis direction and the Y-axis direction orthogonal to each other on a plane, and a measurement mechanism unit that measures the shape of the measurement surface of the measurement object placed on the XY-table A three-dimensional shape measuring apparatus comprising:
The XY-table is a reference plate disposed inside the XY-table so as to face the surface plate. A reference plate for measuring the swell of the XY-table itself when the XY-table is moved. Have
A laser beam generator that is installed on the surface plate and generates a laser beam;
An optical system for a reference plate that is installed on the surface plate and guides the laser light to the reference plate, and is disposed on the surface plate corresponding to the reference plate in a space inside the XY-table. An optical system for a reference plate having a reflection mirror for guiding the laser beam to the reference plate;
It is provided with.

  The XY-table is installed between the surface plate and the XY-table, and slides the XY-table with respect to the surface plate in the X-axis direction or the Y-axis direction, and forms the inner space. The first sliding mechanism includes two first guide rails laid in parallel to form a gap through which the laser beam passes to the reference plate, and each first guide rail. You may comprise so that it may have a 1st base member which slides along each 1st guide rail, respectively engaging, and supporting the said XY-table.

The XY-table further includes a Y-table, an X-table, a Y drive mechanism, an X drive mechanism, and a second sliding mechanism,
The Y-table is installed on the surface plate via the first sliding mechanism and is located in the inner space of the XY-table and moves the Y-table in the Y-axis direction. Have
The X-table is installed on the Y-table via the second sliding mechanism, and has the X driving mechanism for moving the X-table in the X-axis direction,
The second sliding mechanism includes two second guide rails laid in parallel on the Y-table and each second guide rail engaging with each second guide rail to support the X-table. A second base member that slides along the guide rail, and is configured to form a space for placing the X drive mechanism between the X-table and the Y-table. Also good.

  Between the two first guide rails laid in parallel from the outer side of the XY-table to the inner space, the inclination angle of the reflecting mirror disposed in the inner space is set to the angle of the XY-table. An inclination angle adjusting mechanism that adjusts from the outside can be further provided.

  The heat generated from the laser light generation unit by standing on the surface plate and dividing the inside of the three-dimensional shape measuring apparatus into a first region having the XY-table and a second region having the laser light generation unit. It is also possible to further include a dividing member that reduces the influence on the shape measurement of the measurement surface.

  In the second region, the dividing member is separated from the first mounting member and the first mounting member to which the laser light generation unit is attached at an upper portion in the vertical direction, and is below the first mounting member. And a second mounting member for mounting the measurement mechanism section.

  According to the three-dimensional shape measuring apparatus in the first aspect of the present invention, the optical system for the reference plate is arranged on the surface plate, and the reference plate installed on the measurement table is irradiated with the laser beam on the surface plate. Configured. Therefore, the configuration of passing the laser beam through the portion where the upward air flow is generated in the conventional apparatus is unnecessary, and the laser beam is not fluctuated, and the shape measurement accuracy of the measurement surface can be improved as compared with the conventional device. In addition, since the optical system for the reference plate is arranged on the surface plate, the gantry necessary for the conventional apparatus is not necessary. Therefore, it is possible to reduce the size of the entire apparatus as compared with the conventional case.

  Further, since the first sliding mechanism having the first guide rail and the first pedestal member is used, it is not necessary to use a roller bearing conventionally used for the sliding portion of the XY-table. This eliminates the need for horizontal pressurization, which is necessary because of the use of roller bearings, so there is no need to increase the rigidity of the measurement table as in the past, and the thickness of the measurement table is thinner than before. can do. Accordingly, it is possible to form a space in which the reflection mirror provided in the optical system for the reference plate can be installed inside the measurement table. As described above, the optical system for the reference plate can be arranged on the surface plate. Therefore, the measurement accuracy can be improved and the apparatus can be downsized.

  In addition, since the first sliding mechanism has a configuration in which two first guide rails are arranged in parallel, a gap is formed between the first guide rails. Therefore, it is possible to guide the laser beam to the reflection mirror disposed in the inner space of the measurement table using the gap.

  In addition, by providing the first sliding mechanism, a gap can be formed between the Y-table constituting the measurement table and the surface plate, and two second guide rails can be formed as in the first sliding mechanism. By using the second sliding mechanism having the second pedestal member, a gap can also be formed between the Y-table and the X-table constituting the measurement table. Therefore, it becomes possible to install a Y drive mechanism for driving the Y-table inside the measurement table by utilizing the gap between the Y-table and the surface plate, and similarly, the Y-table and the X-table. It is possible to install an X drive mechanism for driving the X-table inside the measurement table using the gap between the measurement table and the table. Therefore, compared with the conventional case where a drive mechanism is provided outside the measurement table, the overall size of the apparatus can be reduced.

  In addition, since the first sliding mechanism is provided as described above, a gap is formed between the first guide rails, so that the inclination angle for adjusting the inclination angle of the reflection mirror disposed in the inner space is adjusted. The adjustment mechanism can be installed using the gap. Therefore, it is possible to adjust the tilt angle of the reflection mirror from the outside of the measurement table, that is, in a good workability state, and it is possible to improve the measurement accuracy and downsize the apparatus.

  In addition, since the split member is installed on the surface plate, the laser beam generation unit that is a heat source can be separated from the measurement table, and the heat generated from the laser beam generation unit is prevented from adversely affecting the shape measurement of the measurement surface. be able to. Therefore, it is possible to improve the measurement accuracy compared to the conventional case.

  In addition, the split member is attached with the laser beam generation unit and the measurement mechanism unit, and the attachment members for attaching each of them are separate members. Thereby, it is possible to prevent the heat generated from the laser beam generation unit from being conducted to the measurement mechanism unit. Therefore, length variation and distortion do not occur in the measurement mechanism section, and it is possible to improve measurement accuracy as compared with the conventional case.

A three-dimensional shape measuring apparatus according to an embodiment of the present invention will be described below with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected about the same component.
As shown in FIG. 1, the three-dimensional shape measuring apparatus 101 of the present embodiment is arranged on an XY-table 130 that moves in the X-axis direction and the Y-axis direction orthogonal to each other on a plane, like the measuring apparatus shown in FIG. This is a measuring device that measures the shape of the measurement surface 1a of the object 1 to be measured while bringing a probe into contact with the measurement surface 1a. The X-axis direction corresponds to, for example, the second direction, and the Y-axis direction corresponds to, for example, the first direction. The first direction and the second direction can be changed from each other. The XY-table 130 is an example that functions as a measurement table. In this embodiment, the object 1 to be measured corresponds to a lens for a digital still camera, for example, and the three-dimensional shape measuring apparatus 101 has a measurement surface 1a having a maximum size of about 200 mm square. An apparatus capable of measuring a measuring surface 1a having a curved surface up to about 60 degrees at a crossing angle θ between a tangential direction and a horizontal direction on the measuring surface 1a with a precision of nanometer order. It is.

  As shown in FIGS. 1 and 2, the three-dimensional shape measuring apparatus 101 is roughly divided into various components such as an XY-table 130, which will be described below in relation to the shape measurement of the measurement surface 1a, and the above various types. And a stone surface plate 105 on which a part of the component is placed. More specifically, the cover 103 covers the measuring device 101 and the front surface corresponding to the operation surface of the device main body is provided on the cover 103 and can be opened and closed. A gate 106 that divides a space 106 surrounded by the door 104, the stone surface plate 105, and the cover 103 into a front region 106a corresponding to the operation side of the apparatus main body and a rear region 106b corresponding to the non-operation side. A split plate 160 made of a low thermal expansion material such as stone, for example, is provided in a single plate shape instead of a mold shape.

  The front area 106a mainly includes an XY-table 130 and a Z-table 140 that is disposed above the XY-table 130 and is a mechanism for measuring the Z-axis seating value of the measurement surface 1a. . On the other hand, the rear region 106b includes a laser beam generator 110 that generates a laser beam 111 for shape measurement, and a measurement mechanism unit 120. Each of these components will be described below.

  3 and 4, the XY-table 130 includes a Y-table 131, a first sliding mechanism 133, an X-table 132, a second sliding mechanism 134, a Y driving mechanism 135, and an X driving. A mechanism 136 and a measurement object placing plate 138 are provided.

  A base plate 107 is mounted on the stone surface plate 105, and a first sliding mechanism 133 that allows the flat Y-table 131 to slide in the Y-axis direction is installed on the base plate 107. Yes. Note that the base plate 107 may be omitted. The first sliding mechanism 133 is the same mechanism as the second sliding mechanism 134 described below, and as shown in FIG. 4, two first guide rails 1331 laid in parallel along the Y-axis direction, The first pedestal member 1332 that engages on each first guide rail 1331 and supports the Y-table 131 is provided. The first pedestal member 1332 has a concave shape so as to hold the first guide rail 1331, and is attached to the first guide rail 1331 at a predetermined interval, and slides along the first guide rail 1331. To do. Therefore, the Y-table 131 is supported by a total of four first base members 1332 and can slide along the first guide rail 1331 in the Y-axis direction.

The first sliding mechanism 133 having such a structure is not a roller bearing that requires pressure in the horizontal direction as in the prior art. Therefore, it is not necessary to consider the rigidity of the Y-table 131 compared to the conventional case, and the thickness of the Y-table 131 can be reduced. Further, as described above, the first sliding mechanism 133 has a structure in which the first base member 1332 slides on the first guide rail 1331. For these reasons, by installing the first sliding mechanism 133 between the stone surface plate 105, that is, the base plate 107 and the Y-table 131, the Z-axis between the base plate 107 and the Y-table 131 is set. A space 151 can be formed in the direction. The formation of the space 151 makes it possible to dispose the Y drive mechanism 135 and a reflection mirror 1221 described later on the inside of the XY-table 130, and in the gap 1511 between the two first guide rails 1331, An optical path for guiding the laser beam 111d to the reflection mirror 1221 can be formed. As will be described in detail later, the reflection mirror 1221 is provided with an inclination angle adjustment mechanism 170 for adjusting the inclination angle of the reflection mirror 1221, and the space 151 includes both the inclination angle adjustment mechanism 170 and the XY-table. It can be arranged inside 130.
An opening 131a is formed in the center of the Y-table 131 so as to allow the laser beam 111d that enters and reflects the reflection mirror 1221 to pass therethrough.

  As shown in FIG. 7, the Y drive mechanism 135 includes a shaft 1351 extending and fixed in the Y-axis direction, and a linear unit having a motor unit 1352 that slides along the shaft 1351 without contact with the shaft 1351. Consists of a motor. The motor unit 1352 is fixed to the Y-table 131, and the shaft 1351 is fixed to the base plate 107. Therefore, when the motor unit 1352 moves with respect to the shaft 1351, the Y-table 131 moves in the Y-axis direction.

On the Y-table 131 configured as described above, a second sliding mechanism 134 having the same configuration as that of the first sliding mechanism 133 described above is installed. That is, as shown in FIG. 3, the second sliding mechanism 134 is engaged with two second guide rails 1341 laid in parallel along the X-axis direction and the respective second guide rails 1341. A second pedestal member 1342 that supports the table 132;
Therefore, the plate-like X-table 132 is supported by the total of the second pedestal members 1342 and is slidable along the second guide rail 1341 in the X-axis direction. Note that an opening 132 a through which the laser beam 111 d reflected by the reflection mirror 1221 can pass is formed at the center of the X-table 132.

  By providing the second sliding mechanism 134 between the Y-table 131 and the X-table 132 in this way, the same effect as that obtained by providing the first sliding mechanism 133, that is, the X-table 132 has the same effect. The wall thickness can be reduced, a space 1512 can be formed in the Z-axis direction between the Y-table 131 and the X-table 132, and the X drive mechanism 136 can be installed inside the XY-table 130. The X drive mechanism 136 has the same configuration as the Y drive mechanism 135 described above, and slides along the shaft 1361 in a non-contact manner with the shaft 1361 extending and fixed in the X-axis direction. And a linear motor having a motor unit 1362. Therefore, when the motor unit 1362 moves with respect to the shaft 1361, the X-table 132 moves in the X-axis direction.

The measurement object mounting plate 138 is supported on the upper surface 132b of the X-table 132 via support balls 1381 arranged at, for example, three locations on the circumference at equal intervals, and is placed on the center of the upper surface 138a. The measurement object 1 is placed and held. In addition, the upper surface 138a has a mirror surface orthogonal to the X-axis direction to detect the movement amount of the XY-table 130 in the X-axis direction and the Y-axis direction, that is, the movement amount of the measurement surface 1a in the X-axis direction and the Y-axis direction. An X-axis reference plate 137X having a reference surface 137Xa and a Y-axis reference plate 137Y having a reference surface 137Ya that is perpendicular to the Y-axis direction and is a mirror surface are attached. Further, the measurement object is set such that the reference plate 137Z for detecting a so-called swell component of the XY-table 130 in the Z-axis direction generated in the XY-table 130 when the XY-table 130 moves is opposed to the object 1 to be measured. It is provided at the center of the back surface 138 b of the mounting plate 138. The reference plate 137Z has an L-shaped cross section projecting from the back surface 138b so that the reference surface 137Za, which is a mirror surface irradiated with the laser beam 111d, is orthogonal to the vertical direction and the orientation of the reference surface 137a is adjustable. Is supported by the arm member 1382. Therefore, when the XY-table 130 moves in the X and Y axis directions, the reference plate 137Z also moves in the X and Y axis directions.
The reference surfaces 137Xa, 137Ya, and 137Za of the respective reference plates 137X, 137Y, and 137Z have a flatness on the order of 0.01 microns.

  The Z-table 140 is mounted on the dividing member 160 so as to be movable along the Z-axis direction above the XY-table 130, and below the Z-table 140, on the measurement surface 1a. A measuring object measuring device 102 is provided for detecting fine movement in the vertical direction of a probe having a stylus in contact therewith, that is, detecting the shape of the measurement surface 1a in the Z-axis direction. The position of the Z-table 140 is controlled in the Z-axis direction so that the stylus of the measurement object measuring device 102 contacts the measurement surface 1a with a substantially constant contact force.

  Next, the tilt angle adjusting mechanism 170 will be described. As shown in FIG. 5, the tilt angle adjustment mechanism 170 includes a movable mirror mounting block 171, an extension block 172 fixed to the base plate 107, and an adjustment unit 173. The mirror mounting block 171 is a member in which the reflection mirror 1221 is mounted on a tapered portion 1711 inclined at an angle of about 45 degrees with respect to the Z-axis direction, and is positioned in the inner space 151 of the XY-table 130 as described above. To do. The extension block 172 is a member for changing the inclination angle of the taper portion 1711 of the mirror mounting block 171 disposed in the inner space 151, that is, the inclination angle of the reflection mirror 1221 from the outside of the XY-table 130. As shown in FIGS. 1 and 4, the first guide rail 1331 is arranged between the two first guide rails 1331, and is fixed to the base plate 107. An adjustment unit 173 is attached to the extension block 172. The adjustment unit 173 includes one support ball 1731, one tension member 1732, and two adjustment screws 1733 and 1734. The tension member 1732 is a member that holds the mirror mounting block 171 in such a manner that it can swing with respect to the fixed extension block 172 with the support ball 1731 as a fulcrum and a center, and has a spring 1732a. Is pulled to the extension block 172 side by the restoring force of the spring 1732a. Further, the tension member 1732 is disposed at the center of gravity of the triangle formed by the support ball 1731 and the adjusting screws 1733 and 1734. The adjusting screws 1733 and 1734 are screwed into the extension block 172, and the tip is brought into contact with the mirror mounting block 171 pulled to the extension block 172 side by the tension member 1732, thereby adjusting the screwing amount. This is a screw for adjusting the angle of the reflection mirror 1221 by swinging the head.

  With respect to the tilt angle adjusting mechanism 170 configured as described above, the angle of the reflection mirror 1221 is adjusted by rotating at least one of the adjusting screws 1733 and 1734 from the outside of the XY-table 130 and moving back and forth in the Y-axis direction. The mirror mounting block 171 is moved by swinging around the support ball 1731, that is, tilting about the Z axis or tilting about the X axis. The mirror mounting block 171, that is, the reflection mirror 1221 can hold the adjustment position by fixing with the fixing nut 1735 provided on the adjusting screws 1733 and 1734 and the restoring force of the spring 1732 a.

  In the three-dimensional shape measuring apparatus 101 according to the present embodiment, the Y-table 131 is disposed on the base plate 107 via the first sliding mechanism 133. However, the configuration is not limited thereto, and the first table on the base plate 107 is used. The X-table 132 may be arranged via the two sliding mechanisms 134, and the Y-table 131 may be arranged on the X-table 132 via the first sliding mechanism 133.

  Next, the dividing member 160 is a member that divides the front region 106a and the rear region 106b and suppresses heat generated in the rear region 106b from affecting the front region 106a due to the division. Thus, the division member 160 can contribute to the improvement of the measurement accuracy of the measurement surface 1a. The split member 160 is provided with four through holes 162a to 162d for reciprocating laser beams 111a to 111d described below between the rear region 106b and the front region 106a.

  The laser beam generator 110 provided in the rear region 106b generates a He—Ne frequency stabilized laser that oscillates at one frequency in this embodiment as the laser beam 111 for shape measurement. The laser beam used may have two frequencies. The laser beam generator 110 is installed on a first mounting member 161 that is mounted on the split member 160.

  The measurement mechanism unit 120 provided in the rear region 106b includes optical systems 1201a to 1201d that divide the laser beam 111 into four parts and guide them, and laser beams 111a to 111d guided by the optical systems 1201a to 1201d. , And detecting units 121a to 121d for obtaining coordinate values in the X-axis, Y-axis, and Z-axis directions at the measurement points on the measurement surface 1a. The measurement mechanism 120 is separated from the first attachment member 161 attached to the split member 160 and is attached to the split member 160 below the laser light generator 110 in the Z-axis direction. Installed on the member 163.

  As described above, the laser light generation unit 110 serving as a heat source is disposed above the measurement mechanism unit 120 and the first mounting member 161 and the second mounting member 163 are separated. It is possible to reduce the influence of the heat generated in the step 120 on the measurement mechanism unit 120. Therefore, the shape measurement accuracy of the measurement surface 1a can be improved as compared with the conventional case.

  The detection unit 121a is a part for detecting the Z-axis coordinate value at the measurement point on the measurement surface 1a based on the laser beam irradiated to the measuring object measuring device 102 and the reflected laser beam reflected with respect to the laser beam 111a. is there. The detection unit 121b is a part for detecting the X-axis coordinate value at the measurement point of the measurement surface 1a based on the laser beam irradiated to the X-axis reference plate 137X and the reflected laser beam reflected with respect to the laser beam 111b. The detection unit 121c is a part for detecting the Y-axis coordinate value at the measurement point of the measurement surface 1a based on the laser beam irradiated to the Y-axis reference plate 137Y and the reflected laser beam reflected with respect to the laser beam 111c. The detection unit 121d is a part for detecting the swell component in the Z-axis direction at the measurement point of the measurement surface 1a based on the laser beam irradiated to the reference plate 137Z and the reflected laser beam reflected with respect to the laser beam 111d. .

The optical system 1201d related to the laser beam 111d between the reference plate 137Z and the measurement mechanism unit 120 is referred to as a reference plate optical system 122. The reference plate optical system 122 includes the reflection mirror 1221 described above. In addition, the laser beam 111d related to the reference plate 137Z is guided to the reflection mirror 1221 through the through hole 162d and the gap 1511 and the space 151 formed by the first sliding mechanism 133. As described above, in the present embodiment, the reference plate optical system 122 is installed on the stone surface plate 105 and does not adopt a configuration in which laser light passes through the stone surface plate unlike the conventional case. Therefore, problems such as fluctuations in laser light that have occurred in the past do not occur, and the shape of the measurement surface 1a can be measured with higher accuracy than in the past.
Moreover, in this embodiment, since it is not necessary to arrange | position an optical system under the stone surface plate, the stand which mounts the stone surface plate which existed conventionally can be removed. As a result, the entire apparatus can be reduced in size. However, it is free to add a pedestal if necessary.

  Note that, as described in Patent Document 2, the shape measurement method of the measurement surface 1a by the measurement mechanism unit 120 using the respective reference surfaces 137Xa, 137Ya, 137Za and the laser beam 111 is reflected on the respective reference surfaces. A known laser length measurement method is used in which the phase change of the reflected laser beam is detected by counting interference signals between the laser beam irradiated to each reference surface and the reflected laser beam. Such a laser length measurement method, for example, as disclosed in Japanese Patent Laid-Open No. 4-1503, divides the laser light irradiated onto the reference surface into reference light and measurement light by a branching member such as a prism, In addition, the phases of the reference light and the measurement light are shifted by 90 degrees. Then, Lissajous is produced from the interference fringe signal obtained by irradiating and reflecting the measurement light on the reference surface, electrically detecting the interference light due to the phase shift in the reflected light and the reference light that have returned. The distance between the reference point and the reference surface is measured based on the figure. Such a length measurement method is performed in each of the detection units 121a to 121d, and the shape of the measurement surface 1a is calculated by the length measurement calculation device based on the detection result.

The three-dimensional shape measuring apparatus 101 of the present embodiment configured as described above operates as follows.
When measuring the shape of the measurement surface 1a, the measuring object measuring device 102 contacts the measurement surface 1a, and the XY-table 130 moves in any direction in the X-axis direction and the Y-axis direction. Therefore, the reference plate 137Z held by the measurement object placing plate 138 placed on the X-table 132 also moves simultaneously. Further, while the position of the Z-table 140 is controlled in the Z-axis direction so that the contact force between the measurement object measuring device 102 and the measurement surface 1a is substantially constant, the measurement object measuring device 102 is placed on the measurement surface 1a. Move along.
As the XY-table 130 moves, as described above, the laser beams 111a to 111d reciprocate between the measurement mechanism unit 120 and the reference plates 137X, 137Y, and 137Z, so that the surface shape of the measurement surface 1a is changed. Measured.

As described above, according to the three-dimensional shape measuring apparatus 101 of the present embodiment, the following effects can be obtained.
That is, with respect to the XY-table, since the first sliding mechanism 133 and the second sliding mechanism 134 are adopted without the conventional roller bearings, in the X-axis direction and the Y-axis direction to prevent rattling in the roller bearings. Therefore, the thickness of the Y-table 131 and the X-table 132 in the X-axis direction and the Y-axis direction can be reduced. Therefore, the space 151 can be formed inside the XY-table 130, and the reflection mirror 1221 can be arranged in the space 151. Therefore, the reference plate optical system 122 including the reflection mirror 1221 can be disposed on the stone surface plate 105, and the conventional configuration of passing the laser beam through the through hole of the stone surface plate can be eliminated. . Therefore, the ascending air current from the lower part of the stone platen is eliminated, the fluctuation of the laser beam can be prevented, and high-accuracy measurement can be realized.

  Further, since the first sliding mechanism 133 and the second sliding mechanism 134 are employed, a space 151 is formed between the stone surface plate 105 and the Y-table 131 and between the Y-table 131 and the X-table 132. The drive source of the Y-table 131 and the X-table 132 can be installed inside the XY-table 130. Therefore, it is possible to reduce the size of the entire apparatus.

  In the three-dimensional shape measuring apparatus 101, (1) the Z-table 140 and the XY-table 130 are provided separately, and (2) the laser beam generator 110 is placed above the dividing member 160. It is attached to the split member 160 via the second attachment member 163 which is attached via the attachment member 161 and further has the measurement mechanism part 120 disposed below the laser light generation part 110 and separated from the first attachment member 161. The overall size of the apparatus can be reduced from the three points of the mounting point and (3) the point plate optical system 122 provided on the stone surface plate 105.

  Further, the space 106 in the three-dimensional shape measuring apparatus 101 is divided into the front region 106 a and the rear region 106 b by the single divided member 160, so that the rising air flow due to heat generated from the laser light generation unit 110 is divided. The occurrence of the air fluctuation can be made only on the rear region 106b side, and the laser light fluctuation caused by the air fluctuation can be prevented. Therefore, more accurate measurement can be realized.

  Further, the laser beam generation unit 110 is disposed above the measurement mechanism unit 120 in the Z-axis direction, and the first mounting member 161 and the second mounting member 163 are separated from each other. The heat conduction to the second mounting member 163 can be reduced. Therefore, length variation and distortion due to thermal expansion in the second attachment member 163 to which the measurement mechanism unit 120 is attached can be eliminated, and laser optical axis misalignment and the like can be eliminated. Thus, the thermal deformation of the measurement mechanism unit 120 can be suppressed as much as possible, and more accurate measurement can be realized.

  Further, since the reference plate optical system 122 is provided on the stone surface plate 105, the reflection mirror 1221 can be disposed in a bright and wide place on the stone surface plate 105, and therefore the angle adjustment work of the reflection mirror 1221 can be performed. Easy and accurate angle adjustment is possible.

  The present invention can be applied to a three-dimensional shape measuring apparatus capable of measuring a surface to be measured on an object to be measured such as an optical component or a mold with ultra-high accuracy on the order of nanometers, for example.

It is sectional drawing which shows the structure of the three-dimensional shape measuring apparatus in embodiment of this invention. It is a front view of the three-dimensional shape measuring apparatus shown in FIG. It is sectional drawing in the BB part of the three-dimensional shape measuring apparatus shown in FIG. It is sectional drawing in the X-axis direction around XY-table shown in FIG. It is sectional drawing of the inclination angle adjustment mechanism shown in FIG. It is sectional drawing in the DD part of the inclination-angle adjustment mechanism shown in FIG. FIG. 2 is a detailed view of a Y drive mechanism and an X drive mechanism shown in FIG. 1. It is a figure which shows the structure of the conventional three-dimensional shape measuring apparatus. It is a front view of the type of three-dimensional shape measuring apparatus different from FIG. FIG. 10 shows a structure of the conventional three-dimensional shape measuring apparatus shown in FIG. 9 and is a cross-sectional view taken along line EE in FIG. 9. It is sectional drawing in the Y-axis direction of the XY-table with which the conventional three-dimensional shape measuring apparatus shown in FIG. 9 is equipped. It is sectional drawing in the X-axis direction of the XY-table with which the conventional three-dimensional shape measuring apparatus shown in FIG. 9 is equipped. FIG. 10 is a perspective view showing an XY-table driving unit provided in the conventional three-dimensional shape measuring apparatus shown in FIG. 9.

Explanation of symbols

1 ... object to be measured, 1a ... measurement surface,
101 ... Three-dimensional shape measuring device, 105 ... Stone surface plate,
106a ... 1st area | region, 106b ... 2nd area | region,
110 ... Laser light generator, 111 ... Laser light, 122 ... Optical system for reference plate,
130 ... XY-table, 131 ... Y-table, 132 ... X-table,
133 ... 1st sliding mechanism, 134 ... 2nd sliding mechanism, 135 ... Y drive mechanism,
136 ... X drive mechanism, 137Z ... reference plate, 138 ... measurement object placement plate,
151 ... Inner space, 160 ... Dividing member, 161 ... First mounting member,
163 ... second mounting member, 170 ... tilt angle adjustment mechanism,
1221 ... Reflecting mirror, 1331 ... First guide rail, 1332 ... First pedestal member,
1341 ... 2nd guide rail, 1342 ... 2nd base member, 1511 ... Clearance,
1512 ... Space.

Claims (3)

A laser light generator for generating laser light;
An optical system for branching the laser beam into a plurality of parts;
A measurement table installed on a surface plate and moving in a first direction and a second direction orthogonal to each other;
A detector that measures the shape of the measurement surface of the object to be measured placed on the measurement table using a part of the branched laser beam;
A reference plate disposed on the surface of the measurement table opposite to the surface on which the object to be measured is placed;
A reference plate optical system that is provided in the optical system and guides another part of the branched laser light to the reference plate;
A reflection mirror facing the reference plate of the optical system for the reference plate is disposed in an inner space between the surface plate and the measurement table ;
The measurement table includes a first sliding mechanism for sliding the measurement table in the first direction, and a second sliding mechanism for sliding in the second direction,
The first sliding mechanism is engaged with two first guide rails laid in parallel to form a gap through which the laser beam passes to the reference plate, and the first guide rails, respectively. A first pedestal member that slides along one guide rail,
The second sliding mechanism is engaged with two second guide rails laid in parallel to each other perpendicular to the first guide rail, and on each second guide rail, along the second guide rail. A second base member that slides;
A three-dimensional shape measuring apparatus. An inclination angle adjusting mechanism that extends between the two first guide rails laid in parallel from the outside of the measurement table to the inside space, and adjusts the inclination angle of the reflection mirror from the outside of the measurement table; The three-dimensional shape measuring apparatus according to claim 1 provided . The three-dimensional shape measuring apparatus according to claim 1, further comprising a dividing member that divides the surface plate into a first region having the measurement table and a second region having the laser light generation unit .

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