JP5468721B2 - Displacement detector and shape measuring device - Google Patents

Description

  The present invention relates to a displacement detector for measuring the surface shape and the like of a lens and other optical elements, and a shape measuring apparatus incorporating the same.

Conventionally, various techniques have been proposed as techniques for measuring a three-dimensional shape (three-dimensional shape) of an optical element (so-called microlens) having a size of 50 mm or less as an object to be measured. For example, there is a contact-type measurement method in which a stylus is brought into direct contact with the surface of an object to be measured and the amount of displacement is measured (see Patent Document 1). In addition, a non-contact measurement method has been proposed in which a laser beam or the like is incident on the surface of an object to be measured and the surface irregularities are measured by receiving the reflected light (see Patent Document 2). The former contact-type measurement method does not depend on the surface physical properties of the object to be measured because the stylus is brought into direct contact with the object to be measured. For this reason, the contact-type measurement method can accurately measure various objects to be measured.
JP-A-5-209741 Japanese Patent No. 3046635

  However, in the above-described contact type measurement method, the variation in the contact pressure is the same as the difference in the deformation amount of the object to be measured, resulting in a measurement error. Therefore, in order to improve the measurement accuracy, it is necessary to keep the contact pressure constant more precisely.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a displacement detector that can easily support a stylus and can increase the accuracy of surface shape measurement.

  It is another object of the present invention to provide a highly accurate and compact shape measuring apparatus incorporating the above displacement detector.

To solve the above problems, engaging Ru displacement detector of the present invention a rod member for supporting the one axial end of the contact body in contact with the sensing object which is measured, the axial and vertical direction the A holding body that holds the rod member so as to be movable in the vertical direction so that the one end portion is a lower end, and a vertical upward direction along the axial direction with respect to the rod member by using atmospheric pressure. A first urging unit that applies one urging force, and a mechanism that differs from the first urging unit by applying a second urging force that is constant upward in the vertical direction along the axial direction to the rod member . Different types of second urging means that operate in the above-described manner, and both of the urging forces of the first and second urging means are smaller than the force of the weight of the rod member .

In the displacement detector, the first and second biasing means, because it provides a predetermined biasing force upward in the vertical direction along the axial direction relative to the rod member, a first biasing means the weight of the rod member It will be shared and supported by the second urging member. As a result, the levitation force applied to the rod member by a pair of different types of urging means can be made relatively small, so that the responsiveness of the rod member is ensured and applied by the first and second urging means. The setting accuracy of levitation force can be improved. As a result, not only the contact pressure of the contact body with respect to the detection target can be set minutely, but also the contact pressure can be set with high resolution (that is, high accuracy). Thereby, since the contact pressure of the contact body with respect to a to-be-detected body can be set with high precision, the displacement amount detection accuracy of a rod member or a shaft-like member can be raised, and the measurement accuracy of the surface shape of the to-be-detected body can be improved. Can be improved.

  In a specific aspect or aspect of the present invention, in the first and second displacement detectors, the shaft through which the first urging means is inserted into an insertion hole of an outer frame body constituting the holding body. A stress generating surface formed to face the one end side of the side surface of the cylindrical member, and vertically upward along the axial direction by applying a predetermined atmospheric pressure to the stress generating surface of the axial member. And an axial levitation means for providing a levitation force corresponding to the first urging force.

  In the displacement amount detector, the axial levitation means constituting the first urging means gives a levitation force upward in the vertical direction by applying a predetermined atmospheric pressure to the stress generating surface. At this time, the levitation force applied to the shaft-like member by the axial levitation means via the stress generating surface can be made relatively small, so that the setting accuracy of the levitation force can be improved. As a result, not only can the contact pressure of the contact body with respect to the object to be detected be set minutely, but also the contact pressure can be set with high resolution.

  In another aspect of the present invention, a bearing portion that is disposed between a side surface of the shaft-shaped member and an inner surface of the outer frame body and supports the shaft-shaped member in a state displaceable in the axial direction without contact. Is provided. In this case, since the bearing portion supports the shaft-like member in a non-contact manner, the play in the horizontal direction perpendicular to the axial direction can be reduced.

  In yet another aspect of the present invention, pressure control is performed to statically support the shaft-shaped member in a non-contact state by applying an air pressure between the inner surface and the outer wall surface of the shaft-shaped member on the inner surface of the bearing portion. Part. In this case, since the shaft-like member is supported in a non-contact state on the bearing portion, it is possible to improve the responsiveness of the displacement of the shaft-like member, and it is possible to measure the displacement amount precisely and with high accuracy.

  In still another aspect of the present invention, in the displacement detector, the stress generating surface is formed in a stepped portion provided on the side surface of the shaft-shaped member. In this case, a stress generating surface can be easily formed on the side surface of the shaft-shaped member.

  In still another aspect of the present invention, the levitation force applied to the shaft-shaped member by the axial levitation means is smaller than the second urging force applied to the shaft-shaped member by the second urging means. In this case, the setting accuracy of the levitation force can be further improved, and the contact pressure of the contact body with respect to the detected body can be made higher resolution.

  In still another aspect of the present invention, the levitation force applied to the shaft-shaped member by the axial levitation means is the shape of the detected body, the surface hardness of the detected body, the total weight of the shaft-shaped member and the contact body, It is set based on at least one of the second urging force applied by the urging means and the hardness of the contact body. In this case, the levitation force can be set to a reasonable value according to the measurement conditions.

  In still another aspect of the present invention, the device includes a portion to be measured that is used when detecting the amount of displacement in the axial direction of the shaft-shaped member. In this case, by detecting the displacement of the portion to be measured, the displacement of the shaft-like member and thus the surface shape of the detected body can be measured.

  In yet another aspect of the present invention, the part to be measured has a light detection surface that reflects the inspection light. In this case, the displacement amount of the shaft-like member can be measured with high accuracy while being non-contact.

  In still another aspect of the present invention, the contact body is attached to the main body of the shaft-like member in a replaceable manner. In this case, the contact body matched with the material and shape of the to-be-detected body can be selected and attached to one end of the shaft-shaped member.

  In still another aspect of the present invention, a displacement sensor that detects the amount of axial displacement of the shaft-like member is provided. In this case, the displacement sensor can measure the displacement amount of the shaft member, that is, the displacement amount of the contact body, and based on the measurement result, the undulation of the surface of the detection object can be measured.

  The shape measuring apparatus according to the present invention includes the above-described displacement detector, a moving means for moving the detected body relative to the shaft member in a direction perpendicular to the axial direction, and a relative movement of the detected body by the moving means. Computation means for calculating the amount of axial displacement of the shaft-like member caused by contact between the surface of the detected body and the contact body based on the output of the displacement sensor and measuring the shape of the detected body.

  In the shape measuring apparatus, the displacement of the shaft-shaped member is calculated from the output of the displacement sensor by the computing means while the detected body is moved relative to the shaft-shaped member by the moving means. It can be efficiently measured as a series of processes.

  Hereinafter, a displacement detector according to an embodiment of the present invention will be specifically described with reference to the drawings. The displacement detector is incorporated in the surface shape measuring device.

  FIG. 1 is a front view of a displacement detector 10 according to the embodiment, and FIG. 2 is an enlarged side sectional view for explaining a main part of the displacement detector 10 shown in FIG.

The displacement detector 10 includes a probe device 10A on the main body side and a laser interferometer 10B that detects the displacement of the movable part of the probe device 10A. Here, the probe device 10 </ b> A includes a cylinder block 2 that is an outer frame body or a holding body, a rod member 3 including a shaft-shaped member, a support body 4, a support member 5, and a coil spring 6.

  In the probe apparatus 10A, the cylinder block 2 is fixed to the support body 4 and supported in a stable state. The cylinder block 2 is a portion that holds the rod member 3 such that its axial direction extends in the vertical direction, that is, the Z direction, and has a rod insertion hole 21 at the center as shown in FIG. The rod insertion hole 21 has a substantially rectangular cross section and extends along the Z direction in which the cylinder block 2 should extend. The rod insertion hole 21 penetrates in the Z direction and opens at the center of the upper and lower end faces of the cylinder block 2.

  The latter rod member 3 is a part that moves up and down in the ± Z direction following the surface shape of the workpiece W that is a measurement object or a detection object, and is inserted into a rod insertion hole 21 provided in the cylinder block 2. It can be displaced in the Z direction, which is the axial direction. The lower end portion 31 which is one end portion of the rod member 3 protrudes downward from the opening on the lower end surface side of the rod insertion hole 21, and the upper end portion 33 of the rod member 3 is the opening on the upper end surface side of the rod insertion hole 21. Protrudes upward from the top. In addition, the rod member 3 is provided with a probe main body 35 and a mirror member 36, which will be described later, at both end portions 31 and 33 of a rectangular columnar shaft-shaped member BD, respectively. The shaft-shaped member BD is integrally formed of, for example, a low-expansion coefficient and a lightweight ceramic material.

  A spherical contact portion 35 a made of ruby, diamond or steel is fixed to the tip of the probe main body 35 protruding from the lower end portion 31 of the rod member 3. The contact portion 35a is a contact body for making contact with the workpiece W to be measured, and can be displaced in the Z direction together with the shaft-shaped member BD. By providing such a contact portion 35a, the surface of the workpiece W can be prevented from being damaged by the probe body 35, and the probe body 35 can be stably brought into contact with the surface of the workpiece W. The contact portion 35a can be exchanged together with the probe main body 35. That is, for example, a male screw 35 c is formed on the upper portion of the probe main body 35, and a female screw 35 d is formed on the lower portion of the lower end portion 31. In a state where the probe main body 35 is fixed to the lower end 31, the male screw 35 c and the female screw 35 d provided on both are screwed together to ensure secure fixing. Further, the probe main body 35 can be separated from the lower end 31 by appropriately rotating the probe main body 35 around the axis with respect to the lower end 31, and another type of probe main body 35 is attached to the lower end 31. be able to. That is, a plurality of types of probe main bodies 35 can be used properly according to the forming material and surface shape of the workpiece W, and the material and shape of the contact portion 35a can be appropriately changed. Specifically, a diamond ball, a ruby ball, a steel ball, or the like can be used as the contact portion 35a.

  The upper surface of the Z mirror member 36 which is a measurement target fixed to the upper end portion 33 of the rod member 3 is a mirror surface extending in the XY plane, that is, a light detection surface for detecting the displacement of the rod member 3 in the Z direction. A Z mirror 36a is provided. Since the Z mirror 36a reflects the detection light ML from the displacement sensor provided above, that is, the laser interferometer 10B (see FIG. 1) as the light irradiation means, the laser interferometer 10B uses the rod based on the reflected light RL. The displacement amount of the member 3 can be calculated.

The upper end portion 33 of the rod member 3 is provided with a locking portion 38 that is fixed to the lower end of the coil spring 6 (see FIG. 1) extending from above. The upper end of the coil spring 6 is fixed to a locking portion 51 a provided on the upper end portion 51 of the column member 5 extending vertically upward from the support body 4 that supports the cylinder block 2. That is, the rod member 3 is given an appropriate urging force vertically upward, that is, in the + Z direction while being suspended by the coil spring 6, and the rod member 3 seems to be lightened by partially canceling the weight. It is in a state. Coil spring 6, a driving device type is different from that of the first biasing means comprising a super precision regulator R2, etc., which will be described later, second biasing means for providing a second biasing force in the vertical upward direction with respect to the rod member 3 It is.

  On the side surface 3a of the rod member 3, a stepped portion 39 is formed as a portion for applying an additional levitation force in the + Z direction vertically above. This stepped portion 39 has a stress generating surface 39a formed so as to face the probe main body 35 side, that is, downward in the vertical direction. As will be described in detail later, the stress generating surface 39a plays a role of causing the rod member 3 to generate a thrust (levitation force) upward in the vertical direction that partially eliminates the weight of the rod member 3. By combining the vertical upward thrust applied to the rod member 3 by the step portion 39 and the vertical upward biasing force applied to the rod member 3 by the coil spring 6, the weight of the rod member 3 is reduced. It is possible to make a half-suspended state that cancels out, and it is possible to adjust the force with which the rod member 3 tries to move downward in the vertical direction. Thereby, the contact part 35a of the rod member 3 lower end can be made to contact with the workpiece | work W surface with arbitrary forces.

  An upper bearing member 23 made of a porous body is provided along the inner wall surface 21 a at the upper portion of the inner wall surface 21 a of the rod insertion hole 21 formed in the cylinder block 2. In addition, a lower bearing member 24 made of a porous body is provided along the inner wall surface 21 a at the lower portion of the inner wall surface 21 a of the rod insertion hole 21.

  An air supply port 26 is formed on the outer surface of the cylinder block 2. The air supply port 26 communicates with the inner wall surface 21a of the rod insertion hole 21 via the upper bearing member 23 and the lower bearing member 24 which are bearings, and the pressurized air from the air supply source P is connected to the pipe L1. It is supplied directly via. As a result, the pressurized air from the air supply source P passes through the upper bearing member 23 and the lower bearing member 24, reaches the outer surface, and is ejected toward the side surface 3 a of the rod member 3. The rod member 3 is supported by the static pressure of the pressurized air ejected from the bearing members 23 and 24 in a non-contact manner at appropriate positions above and below the rod insertion hole 21 of the cylinder block 2. That is, both bearing members 23 and 24 function as a static pressure thrust bearing.

  A pressure acting chamber 27 is formed between the upper bearing member 23 and the lower bearing member 24 and below the step portion 39 of the rod member 3. When the rod member 3 is inserted into the rod insertion hole 21, the pressure acting chamber 27 is a semi-airtight structure sandwiched between the inner wall surface 21 a of the rod insertion hole 21 and the side surface 3 a of the rod member 3 or the stress generation surface 39 a. It becomes a space of state.

  A thrust port 28 is formed on the upper middle of the outer surface of the cylinder block 2. The thrust port 28 communicates with the pressure action chamber 27 on the inner wall side of the rod insertion hole 21. Pressurized air from the air supply source P is supplied to the pressure action chamber 27 via the pipe L2 and the ultraprecision regulator R2. Is done. The supply pressure of the control air to the thrust port 28 is monitored by, for example, a pressure sensor PS provided on the path of the pipe L2, and the detection result of the pressure sensor PS is an axial levitation means and incorporates a pressure control valve. It is fed back to the ultraprecision regulator R2. That is, the atmospheric pressure in the pressure working chamber 27 can be adjusted with high precision by the ultraprecision regulator R2, and is remotely controlled by a control device (not shown). The pressure action chamber 27, the thrust port 28, the pressure sensor PS, and the ultraprecision regulator R <b> 2 described above function as a first urging unit that applies a first urging force to the rod member 3 in the vertical direction. Here, the pressure resolution of the ultraprecision regulator R2 is set to about 0.03 to 0.05 Pa, for example. The pressure resolution applied to the rod member 3 by the thrust port 28 is given by (total thrust force of the thrust port 28) / (total air supply pressure of the thrust port 28) × (resolution of the ultraprecision regulator R2). Note that the pressure resolution applied to the rod member 3 by the thrust port 28 is equal to or less than the resolution of the levitation force applied to the rod member 3 by the coil spring 6. This is because when the resolution of the levitation force provided by the coil spring 6 is lower than the resolution of the levitation force provided by the thrust port 28, the pressure control by the ultraprecision regulator R2 is inhibited by the coil spring 6.

  When the control air is supplied to the thrust port 28 by the ultraprecision regulator R2 as described above, the control air acts on the stress generation surface 39a of the step portion 39. That is, the thrust that pushes in the + Z direction on the root side, that is, the floating force, is applied to the rod member 3 by the control air from the thrust port 28. Here, the area of the stress generating surface 39a, which is the step area of the stepped portion 39, can generate the necessary levitation force corresponding to the pressure of the pressurized air, so that the super-precision regulator R2 By controlling the pressure of the pressurized air supplied from the rod member 3, it is possible to apply to the rod member 3 thrust in the vertical direction, that is, lift force, which partially eliminates the weight of the rod member 3 by supplementing the coil spring 6. it can. Furthermore, since the levitation force applied to the rod member 3 by the step portion 39 is changed by changing the pressure value of the pressurized air supplied from the ultraprecision regulator R2, the contact portion 35a at the lower end of the rod member 3 is moved to the workpiece W. The surface can be brought into contact with any pressing force.

FIG. 3 is a graph illustrating the relationship between the pressure value of the pressurized air set by the ultraprecision regulator R2 and the levitation force applied to the rod member 3 by the pressurized air. A solid line indicates a case where the urging force by the coil spring 6 is applied, and an example in which the levitation force by the pressurized air can be set small, and a dotted line indicates an example using only the levitation force by the pressurized air. In any case, the floating force of the rod member 3 can be increased linearly by increasing the pressure value of the pressurized air. However, the smaller the slope value of the barometric pressure value and the levitation force graph, the smaller the resolution of the levitation force of the rod member 3, and the contact portion 35a can be brought into contact with the surface of the workpiece W with a more precise pressing force. Thus, the vertical movement of the rod member 3 can be made more sensitive and precise. In a specific embodiment, the pressure value of the pressurized air as 0～0.2MPa, the resolution of the contact pressure by the contact portion 35a could be a 0.01～0.02MN. On the other hand, in the comparative example in which float the rod member 3 only in compressed air without using the coil spring 6, the pressure value of the pressurized air as 0～0.2MPa, the resolution of the contact pressure by the contact portions 35a 0. It can only be set from 05 to 0.10 mN.

  In a specific measurement example, when a diamond sphere having a radius of 4 μm is used as the contact portion 35a, the pressing force of the contact portion 35a against the surface of the workpiece W, that is, the contact pressure is set to about 15 mg, for example. In another embodiment, when a ruby ball having a radius of 0.25 mm is used as the contact portion 35a, the pressing force of the contact portion 35a against the surface of the workpiece W, that is, the contact pressure is set to about 50 mg, for example.

  The setting of the pressure value of the pressurized air is any one of the surface shape of the workpiece W, the surface hardness of the workpiece W, the total weight of the rod member 3, the levitation force applied by the coil spring 6, and the hardness of the contact portion 35a. It is set based on a combination of two or more. In the above, the surface shape of the workpiece W includes a smooth surface, a step, a V-groove, and the like, and the surface hardness of the workpiece W includes a wide range of hardnesses of various materials including a metal material and a resin material. Further, the total weight of the rod member 3 and the hardness of the contact portion 35a vary depending on which material, such as ruby or diamond, is used for the material of the contact portion 35a.

  Returning to FIG. 1, the laser interferometer 10 </ b> B disposed above the probe device 10 </ b> A has a known structure including a laser light source, an interference optical system, a sensor, and the like, although not shown. The detection light ML laser light from the laser interferometer 10B is irradiated toward the Z mirror 36a of the Z mirror member 36 provided at the upper end of the rod member 3, and the reflected light from the Z mirror 36a. The RL detection light is reflected in the direction of the laser interferometer 10B and is detected by the laser interferometer 10B. In the laser interferometer 10B, the displacement amount in the Z direction of the rod member 3 can be calculated based on the phase change of the reflected light RL.

  In the displacement detector 10, the rod member 3 is supported by the pressurized air supplied from the air supply source P in a non-contact manner with respect to the bearing members 23 and 24 in the rod insertion hole 21. Further, by the control air supplied from the air supply source P to the pressure acting chamber 27 via the thrust port 28, an arbitrary levitation force (thrust) is applied to the rod member 3 in the vertical direction, that is, in the + Z direction. At this time, the rod member 3 is lifted by an urging force that partially cancels its own weight in a state of being hung by the coil spring 6. As a result, the rod member 3 is slightly biased in the −Z direction while almost floating in the cylinder block 2. In this state, the contact member 35a provided at the lower end of the rod member 3 is brought into contact with the surface of the workpiece W, and the probe device 10A is scanned relative to the workpiece W in the XY plane. It is displaced in the ± Z direction along the surface shape of the workpiece W. During the XY scanning of the probe device 10A, the control air supplied to the pressure acting chamber 27 is adjusted so that the contact pressure of the contact portion 35a against the surface of the workpiece W is kept constant at an arbitrarily settable appropriate value. . In parallel with the XY scanning of the probe device 10A, the laser beam from the laser interferometer 10B is irradiated toward the Z mirror 36a, and the displacement amount of the rod member 3 in the Z direction is calculated. Based on this Z displacement amount, the three-dimensional shape of the workpiece W is measured.

  A differential sensor (not shown) is provided at the upper end of the cylinder block 2, for example. This differential sensor is for detecting the direction in which the rod member 3 is displaced from the reference position in the cylinder block 2. As a result, when the rod member 3 rises in the cylinder block 2, for example, an H signal is output, and the entire cylinder block 2 can be gently raised by a mechanism (not shown) accordingly, It becomes possible to return to the position. On the contrary, when the rod member 3 is lowered in the cylinder block 2, for example, an L signal is output, and the cylinder block 2 is gently raised by a mechanism (not shown) in accordance with this to return the rod member 3 to the reference position. Is possible. That is, the probe apparatus 10A can be moved up and down in the ± Z direction as a whole while keeping the position of the rod member 3 with respect to the cylinder block 2 substantially constant.

  FIGS. 4A and 4B are a front view and a side view for explaining the structure of the surface shape measuring apparatus 100 in which the displacement amount detector 10 shown in FIG. 1 is incorporated as both displacement detection means. The surface shape measuring apparatus 100 has a structure in which an XY stage device 82 and a Z driving device 84 are fixed on a surface plate 81. The operations of the XY stage device 82, the Z drive device 84, and the like are controlled by a control device 99 as a calculation output stage.

  The XY stage device 82 is a moving unit, and is operated by being driven by a drive control unit (not shown) under the control of the control device 99. The XY stage device 82 smoothly moves the measurement jig HD, which is detachably fixed on the mounting table 82a provided on the XY stage device 82, two-dimensionally to an arbitrary position in the XY plane. be able to. The position of the measurement jig HD is detected using the X mirror member 83a and the Y mirror member 83b provided on the mounting table 82a. That is, the position of the mounting table 82a in the X-axis direction can be determined using the laser interferometer 83d attached on the surface plate 81 so as to face the X mirror member 83a. Further, the position of the mounting table 82a in the Y-axis direction can be determined by using a laser interferometer 83e mounted on the surface plate 81 so as to face the Y mirror member 83b.

  The Z drive device 84 has a lifting mechanism 86 fixed on a frame 85. The lifting mechanism 86 is fixed to the upper part of the frame 85 and extends in the Z direction, and is supported by the support shaft 86a to be in the Z axis direction. A lifting / lowering member 86b, a lifting / lowering driving device 86c for lifting / lowering the lifting / lowering member 86b, and a probe device 10A supported by the lifting / lowering member 86b.

  In the elevating mechanism 86, the elevating member 86b is supported in a non-contact manner by the support shaft 86a and smoothly moves up and down. The elevating member 86b holds the probe device 10A described in FIG. 1 at the front lower portion, and smoothly elevates as the probe main body 35 provided in the probe device 10A moves up and down. As described with reference to FIG. 2, the probe device 10 </ b> A is supplied with control air from the air supply source P to the air supply port 26, and can move on the Z axis while supporting the rod member 3 in a non-contact manner. Keep in good condition. Further, the probe device 10A is supplied with control air from the air supply source P to the thrust port 28, and can adjust the lifting and lowering force by the ultraprecision regulator R2. As described above, the contact portion 35a provided at the tip of the rod member 3 can be pressed against the surface of the workpiece W with a constant force. That is, even if the optical element fixed to the measurement jig HD, that is, the surface of the workpiece W is moved up and down, the tip of the probe body 35 can be maintained in contact with the surface of the workpiece W with a low load. Further, the lift drive device 86c moves the probe device 10A up and down together with the lift member 86b while applying feedback based on the detection result of the differential sensor built in the probe device 10A. Thereby, the rod member 3 can be moved up and down over a wide range in a state where a constant low load is applied to the tip of the rod member 3. Therefore, the workpiece W placed on the measuring jig HD is moved in the XY plane by appropriately operating the XY stage device 82 while raising and lowering the rod member 3, that is, the probe main body 35 with a constant load as described above. The tip of the probe body 35 can be moved two-dimensionally along the optical surface of the workpiece W placed on the measurement jig HD. That is, the control device 99 associates the XY coordinates of the mounting table 82a obtained using the laser interferometers 83d and 83e with the Z coordinate of the probe main body 35 obtained using the laser interferometer 10B. By appropriately performing arithmetic processing, the three-dimensional surface shape of the optical surface of the workpiece W can be measured.

  The displacement of the tip position of the probe main body 35 is detected using a Z mirror member 36 provided at the upper end of the rod member 3 that moves up and down together with the probe main body 35. That is, the lower end of the probe main body 35 is detected by using the laser interferometer 10B mounted on the frame 85 so as to face the Z mirror member 36 and detecting the reflected light RL while irradiating the Z mirror member 36 with the detection light ML. That is, the position in the Z-axis direction on the surface of the workpiece W is indirectly known.

  Although the present invention has been described based on the above embodiments, the present invention is not limited to the above embodiments. For example, the number and shape of the stepped portion 39 and the stress generating surface 39a formed on the rod member 3 can be changed as appropriate.

  Further, the arrangement and number of the upper bearing member 23 and the lower bearing member 24 can be appropriately changed according to the measurement object, measurement conditions, and the like.

  Further, the coil spring 6 can be replaced with another alternative as long as it can apply a constant urging force to the rod member 3.

  Further, the workpiece W is fixed on the surface plate 81 side, and the rod member 3 is displaced while the displacement amount detector 10 is moved three-dimensionally by the XY stage device 82 and the Z driving device 84 to thereby displace the surface of the workpiece W. The shape can also be measured.

It is a side view of the displacement amount detector which concerns on one Embodiment of this invention. FIG. 2 is a side sectional view of a probe device incorporated in the displacement detector of FIG. 1. It is a graph explaining the relationship between the atmospheric pressure value of the pressurized air supplied to the probe apparatus of FIG. 2, and levitation force. (A) And (b) is the front view and side view explaining the structure of the surface shape measuring apparatus which each incorporated the probe apparatus shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 ... Cylinder block, 3 ... Rod member, 3a ... Side surface, 6 ... Coil spring, 10 ... Displacement amount detector, 10A ... Probe apparatus, 10B ... Laser interferometer, 21 ... Rod insertion hole, 21a ... Inner wall surface, 23, 24 DESCRIPTION OF SYMBOLS ... Bearing member 27 ... Pressure action chamber 28 ... Thrust port 31 ... Lower end part 35 ... Probe main body 35a ... Contact part 36 ... Z mirror member 39 ... Step part 39a ... Stress generating surface

Claims (12)

A rod member including a shaft-like member that supports a contact body that is in contact with the body to be detected, which is a measurement target, at one end in the axial direction;
A holding body for holding the rod member so as to be movable in the vertical direction so that the axial direction is the vertical direction and the one end is the lower end;
First urging means for applying a first urging force vertically upward along the axial direction to the rod member by utilizing atmospheric pressure;
A second urging unit of a different type that applies a second urging force that is constant upward in the vertical direction along the axial direction to the rod member , and operates by a mechanism different from the first urging unit;
With
A displacement amount detector in which both of the urging forces of the first and second urging means are smaller than the force of the weight of the rod member . The first urging means includes a stress generating surface formed to face the one end side on a side surface of the shaft-like member inserted through an insertion hole of an outer frame body constituting the holding body, and the shaft the stress generation surface of Jo member by applying a predetermined air pressure according to claim 1, further comprising an axial levitation means for providing a lifting force corresponding to the first energizing force upward in the vertical direction along the axial direction Displacement detector. The displacement according to claim 2, further comprising a bearing portion that is disposed between a side surface of the shaft-shaped member and an inner surface of the outer frame body and supports the shaft-shaped member in a non-contact manner so as to be displaceable in the axial direction. Quantity detector. An inner surface of the bearing portion, according to claim 3 having a pressure controller for by applying a pressure and static pressure supporting the shaft-like member in a non-contact state between the inner surface and the outer wall surface of the shaft-like member The displacement detector described. The displacement detector according to any one of claims 2 to 4 , wherein the stress generating surface is formed in a stepped portion provided on a side surface of the shaft-shaped member. The axial said lift force by floating means is applied to the shaft-like member, according to claim 5 small claims 2 than the second bias force applied to the shaft-like member by the second biasing means The displacement amount detector according to any one of the above. The levitation force applied to the shaft-shaped member by the axial levitation means includes the shape of the detected body, the surface hardness of the detected body, the total weight of the shaft-shaped member and the contact body, and the second attachment. The displacement detector according to any one of claims 2 to 6 , which is set based on at least one of the second urging force applied by the urging means and the hardness of the contact body. The displacement amount detector according to any one of claims 1 to 7 , wherein the rod member includes a portion to be measured that is used when detecting a displacement amount of the shaft-shaped member in the axial direction. The displacement detector according to claim 8 , wherein the part to be measured has a light detection surface that reflects inspection light. The contact body, the displacement amount detector according to one of claims 1 to 9 which is mounted exchangeably with respect to the shaft-like member. The displacement amount detector according to any one of claims 1 to 10 , further comprising a displacement sensor that detects a displacement amount of the shaft-like member in the axial direction. A displacement detector according to claim 11 ;
Moving means for moving the detected body relative to the axial member in a direction perpendicular to the axial direction;
Based on the output of the displacement sensor, the amount of displacement of the shaft-like member caused by the contact between the surface of the detected body and the contact body during the relative movement of the detected body by the moving means is calculated. A shape measuring device comprising: an arithmetic means for measuring the shape of the body to be detected.

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