JP5645349B2 - Shape measuring device - Google Patents

Description

  The present invention relates to an optical element such as a lens, a mirror, and a prism, and a shape measuring device for measuring the shape of a mold for the optical element.

  2. Description of the Related Art Conventionally, optical elements such as lenses, mirrors, prisms, and the like that require high shape accuracy and shapes of molds thereof are generally measured by a shape measuring device having a contact probe. The contact-type shape measuring device scans in the XY direction while pressing the probe movable in the XYZ space against the measurement surface of the object to be measured with a constant force, and the probe position during the scanning is measured by a laser length measuring device or the like. By measuring, the shape data of the surface to be measured is obtained as XYZ coordinate values. As a general probe structure, the probe shaft is held by an air bearing or the like so that it can slide only in the Z direction in the XYZ space, and a rigid element that generates a force in the vertical direction is used to compensate for its own weight. It is provided between the shafts and is elastically supported.

  A probe ball having a high sphericity is arranged at the tip of the probe shaft, and this is pressed against the surface to be measured with a constant force to perform a measurement operation.

  For measuring optical elements and molds for optical elements that require high precision, such as lenses, measure not only the shape of the surface to be measured but also the surface position from the reference position defined on the element. It has become important. That is, ensuring the relative position and orientation of the end surface and the surface to be measured using the end surface on the optical element as a reference position has become an essential item for measurement of these elements.

  However, it is very difficult to simultaneously measure the shape of the optical surface and measure the end surface for determining the reference position on the optical element with one shape measuring probe. This is because the configuration requirements of the probe required for optical surface measurement and the configuration requirements of the probe required for end surface measurement are contradictory. That is, in the XYZ space, if the optical surface of the object to be measured is parallel to the XY plane and the end surface is parallel to the XZ plane and the YZ plane, as described above, the probe shaft performs optical surface measurement. For that purpose, the rigidity in the direction in which the shaft falls is required to be very high. This is because if the rigidity is weak, the probe shaft is greatly tilted and high-precision optical surface measurement cannot be performed. On the other hand, the measurement of the end face that determines the reference position is performed by a method in which the probe ball provided at the tip of the probe shaft is pressed against the end face from the X direction or the Y direction, which is the lateral direction, and the probe shaft is tilted. ing. For this reason, if the rigidity in the direction in which the shaft falls is extremely increased, the measurement pressure applied to the surface to be measured at the time of measurement increases, which adversely affects measurement accuracy.

  As a conventional example, as disclosed in Patent Document 1, for example, a probe capable of measuring an end face of an object to be measured is proposed. As shown in FIG. 4, when measuring an end face parallel to the YZ direction in the XYZ space, the probe comprising the arm portion 103 having the stylus 101 at the tip and the leaf spring 105 is moved closer to the X direction. . The deformation of the leaf spring 105 due to the contact between the probe and the end surface of the object to be measured is detected by a displacement sensor using the mirror 102 to measure the end surface position.

  Further, as disclosed in Patent Document 2, as shown in FIG. 5, as a probe capable of measuring an end face of an element, a probe including a stylus 212 and an arm 222 is supported on a swing member 220, and the probe and measurement are performed. The surface 251 is brought into contact. Then, the probe tilt is detected by a displacement sensor using a mirror 232, and the probe position at that time is measured by a separate displacement sensor, and the end face is measured with high accuracy.

Japanese Patent No. 3075981 JP 2006-284410 A

  However, the above conventional example has the following problems.

In the configuration disclosed in Patent Document 1, for example, when the probe is arranged in the apparatus so as to measure an end face parallel to or substantially parallel to the YZ plane in the XYZ space, only the end face parallel to the YZ plane can be measured. Thus, the end face parallel to the XZ plane cannot be measured. In order to measure the end face parallel to the XZ plane, it is necessary to take measures such as changing the fixing direction of the measuring element, changing the probe in the direction in which the XZ plane can be measured, or providing another one. The measurement accuracy, device cost, and measurement time are adversely affected.

  In addition, in this configuration, in the case of an optical surface that is normally formed within an inclination of 0 to 60 degrees with respect to the XY plane, measurement cannot be performed. You have to measure with a different device.

  The probe proposed in Patent Document 2 can solve the problem that only a plane parallel to the YZ plane or a plane parallel to the XZ plane can be measured. However, the probe is usually 0 to 60 degrees with respect to the XY plane. The optical surface formed within the inclination cannot be measured.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a shape measuring apparatus capable of performing both measurement of an optical element shape and measurement of an end face for determining a reference surface with a single probe with high accuracy.

The shape measuring apparatus of the present invention includes a probe housing that can be moved three-dimensionally, and a probe that is held so as to be relatively movable with respect to the probe housing, and the scanning control of the probe with respect to the surface of the object to be measured. In the shape measuring device for measuring the coordinate position of the probe representing the surface shape of the object to be measured, the relative displacement of the probe with respect to the probe housing in the direction perpendicular to the longitudinal direction of the probe Based on the output of the measuring means for measuring a certain translational displacement, the force generating means arranged at one place with respect to the longitudinal direction of the probe for generating the translational force on the probe, and the output of the measuring means controls the translational force by generating means, said changing the translational force at the end surface measurement of the object to be measured and the surface measurement of the object to be measured Characterized by comprising a means for rigid and viscosity are set between the probe and the probe housing.

Since the mechanical characteristics between the probe housing and the probe can be changed between the surface measurement of the object to be measured and the end surface measurement of the object to be measured by the force generating means, the measurement of the surface shape of the object to be measured and the reference surface Both of the measurement of the end face shape that determines the above can be performed with high accuracy by one probe.

  The best mode for carrying out the present invention will be described with reference to the drawings.

  As shown in FIG. 1, the shape measuring apparatus according to the first embodiment includes a probe including a probe ball 1 and a probe shaft 2, and a yoke that generates translational and rotational forces in the X and Y directions perpendicular to the probe axis in the Z direction. 3a, 3b, magnetic bodies 3c, 3d, and coils. These are supported by the probe housing 4. Furthermore, a yoke 5a, a magnet 5b, a coil 5c that generate a force in the Z direction, and displacement meters 6a, 6b, and 7 serving as measuring means are provided.

  The probe shaft 2 is disposed freely (relatively movable) with respect to the probe housing 4, and a Z mirror 10 and a probe sphere 1, which is a highly accurate sphere, are fixed to the tip of the probe shaft 2. Yes. The probe housing 4 is installed on the Z-axis table 15 via the probe base 12 and the support column 14, and the X1 interferometer 13 and the X2 interferometer 11 are arranged on the probe base 12, and the interferometer and the X2 are respectively arranged. The distance from the reference mirror 20 is measured. Further, a Y1 interferometer (not shown) and a Y2 interferometer (not shown) are installed on the probe base 12 and measure the distance from the Y reference mirror (not shown). A Z interferometer 16 is installed on the Z-axis table 15, thereby measuring the distance to the Z reference mirror 21.

  The Z-axis table 15 is connected to a Z-axis stage 17, a Y-axis stage 18, and an X-axis stage 19, and can be moved three-dimensionally by these stages. The amount of movement of the Z-axis table 15 is determined by using the X reference interferometer 13, the X2 interferometer 11, the Y1 interferometer, the Y2 interferometer, and the Z interferometer 16, and the X reference mirror 20, the Y reference mirror, and the Z reference mirror 21. Measure with reference to. The above stage is disposed on the base 23, and a reference mirror holding member 22 holding the X reference mirror 20 and the Z reference mirror 21 is fixed on the base 23 in addition to the above stage. . Further, the object to be measured W is fixed so as to be removable.

  An X1 displacement meter 6 a and an X2 displacement meter 6 b are fixed to the probe housing 4, and each displacement meter measures a relative displacement in the X direction between the probe housing 4 and the probe shaft 2. By providing two displacement meters that measure the displacement in the X direction, the displacement and posture (translational displacement and rotational displacement) of the probe shaft 2 can be measured.

  Although not shown, the Y1 displacement meter and the Y2 displacement meter, which are measuring means for measuring the relative displacement in the Y direction between the probe housing 4 and the probe shaft 2, are also fixed to the probe housing 4. Further, a Z displacement meter 7 for measuring the relative displacement in the Z direction between the probe housing 4 and the probe shaft 2 is also fixed to the probe housing 4.

  A Z force generation mechanism that applies a force in the Z direction from the probe housing 4 to the probe shaft 2 is composed of a yoke 5a and a coil 5c fixed to the probe housing 4, and a magnet 5b fixed to the probe shaft 2. Is done. By applying a current to the coil 5c, the magnetic field density between the magnet 5b and the yoke 5a changes, and a force in the Z vertical direction can be applied to the probe shaft 2.

  An X force generating mechanism, which is a force generating means for generating a translational force and a rotational force in the X direction with respect to the probe shaft 2, includes yokes 3 a and 3 b fixed to the probe housing 4 and a magnetic body fixed to the probe shaft 2. 3c and 3d. A coil is wound around the yokes 3a and 3b. By passing an electric current through the coils, the attractive force between the yokes 3a and 3b and the magnetic bodies 3c and 3d is changed. A force in the X direction can be applied. Further, the X force generation mechanism is installed at two positions above and below the probe shaft 2, and a rotational force can be applied to the probe shaft 2 by applying a force by combining these two. Although not shown, a Y force generation mechanism, which is a force generation unit similar to the X direction, is also arranged in the Y direction.

  Next, the signal flow of the apparatus will be described.

  First, there is a main controller (not shown) as the highest level controller of the apparatus. There are three controllers, a measurement controller 24, a stage controller 26, and a force controller 25, as subordinate controllers that receive commands from the main controller.

  Based on an instruction from the main controller, the measurement controller 24 includes an X1 interferometer 13, an X2 interferometer 11, a Y1 interferometer, a Y2 interferometer, a Z interferometer 16, an X1 displacement meter 6a, an X2 displacement meter 6b, a Y1 displacement meter, The displacement data of the Y2 displacement meter and the Z displacement meter 7 are latched simultaneously. Then, the acquired displacement data (output) is transmitted to the main controller.

  The stage controller 26 controls the X-axis stage 19, the Y-axis stage 18, and the Z-axis stage 17 based on an instruction from the main controller. In addition to controlling the position of each stage, Z-axis stage control for making the value of the Z displacement meter 7 constant, X-axis stage control for making the values of the X1 displacement meter 6a and X2 displacement meter 6b constant, Y1 displacement Y-axis stage control is performed to keep the values of the meter and Y2 displacement meter constant.

  Based on an instruction from the main controller, the force controller 25 generates the Z force generation mechanism, the X force generation mechanism, and the Y force generation mechanism from the outputs of the X1 displacement meter 6a, the X2 displacement 6b, the Y1 displacement meter, and the Y2 displacement meter. To control.

  Next, a measurement operation performed using the shape measuring apparatus configured as described above will be described with reference to the flowchart of FIG.

  First, the stage controller 26 sets the Z-axis stage 17 to a position control system. That is, control is performed so that the position of the Z-axis stage 17 becomes constant, and then the Z-axis stage 17 is retracted in a safe position, that is, in a direction in which the probe ball 1 is farthest from the workpiece W (step S01).

  Then, the force controller 25 sets the rigidity and viscosity between the probe shaft 2 and the probe housing 4 suitable for measuring the reference surface (end surface) Wb of the workpiece W having the optical surface (surface) Wa ( Step S02).

  For example, in the probe ball 1, the rigidity in the X translation direction and the Y translation direction is set to 10 mN / mm, the rigidity in the X rotation direction and the Y rotation direction is set to 10 mN / mm, and the viscosity in each direction is set to a damping rate of about 0.7, The rigidity in the Z translation direction is set to 10 N / mm. With this setting, the reference surface Wb can be measured with a very weak force, and the relative vibration between the probe shaft 2 and the probe housing 4 due to moving stage vibration and other disturbance vibrations is suppressed. .

  The rigidity and viscosity are realized by the X1 displacement meter 6a, the X2 displacement meter 6b, the Y1 displacement meter, the Y2 displacement meter, the Z displacement meter 7, the X force generation mechanism, the Z force generation mechanism, the Y force generation mechanism, and the force controller 25. However, a specific control method will be described later.

  The X-axis stage 19 and the Y-axis stage 18 are moved so as to be on the measurement point of the first reference plane (step S03).

  Next, the Z-axis stage 17 is lowered so that the height of the probe ball 1 and the reference surface Wb, which is the end surface of the object W to be measured, are matched (step S04).

  Further, the probe sphere 1 is brought close to the reference plane Wb by the X-axis stage 19 and the Y-axis stage 18, and the probe sphere 1 and the reference plane Wb are brought into contact (step S05). The contact between the probe ball 1 and the reference surface Wb can be detected by observing the X1 displacement meter 6a, the X2 displacement meter 6b, the Y1 displacement meter, and the Y2 displacement meter. That is, when the probe ball 1 is moved from the X plus direction to the X minus direction to approach the reference plane Wb, the outputs of the X1 displacement meter 6a and the X2 displacement meter 6b touch the minus direction at the time of contact. By detecting this, contact can be detected.

  When contact is detected, the stage controller 26 controls the X-axis stage 19, the Y-axis stage 18, and the Z-axis so that the X1 displacement meter 6a, X2 displacement meter 6b, Y1 displacement meter, Y2 displacement meter, and Z displacement meter 7 become constant. The stage 17 is controlled (step S06). From the outputs of the X1 displacement meter 6a, X2 displacement meter 6b, Y1 displacement meter, Y2 displacement meter, Z displacement meter 7, X1 interferometer 13, X2 interferometer 11, Y1 interferometer, Y2 interferometer, Z interferometer 16 The coordinate position of the probe at the measurement point is measured (step S07). The method of calculating the coordinates will be described later.

  After the coordinate measurement, the probe sphere 1 is retracted from the measurement point by the X-axis stage 19 and the Y-axis stage 18 (step S08), and the probe sphere 1 and the object W to be measured are most separated by the Z-axis stage 17. Retreat to a safe position (step S09).

  If measurement of the reference surface Wb (end surface shape measurement) has been completed, the process proceeds to optical surface measurement, and if it is in the middle, the process returns to step S03 to measure the next reference surface (step S10).

  When shifting to the measurement of the optical surface Wa (surface shape measurement), the optical surface Wa is moved to the optical surface measurement start position by the X-axis stage 19 and the Y-axis stage 18 (step S11). Then, the force controller 25 sets rigidity and viscosity between the probe shaft 2 and the probe housing 4 suitable for optical surface measurement. For example, the stiffness in the X translation direction, the Y translation direction, the X rotation direction, and the Y rotation direction in the probe sphere 1 is set to 200 mN / mm, and the stiffness in the Z translation direction is set to 10 mN / mm (step S12). Thereafter, the probe contact determination mode is set and the Z-axis stage 17 is lowered to bring the probe ball 1 and the optical surface Wa of the workpiece W into contact. Contact between the probe ball 1 and the workpiece W can be detected by monitoring the Z displacement meter 7. That is, when the probe ball 1 and the workpiece W are in contact with each other, the probe shaft 2 is pushed up in the Z + direction, so that the output of the Z displacement meter 7 changes in the + direction, so that the contact can be detected.

  When the probe ball 1 and the workpiece W are in contact, the probe contact determination mode is canceled (step S14), and the needle pressure of the Z-axis stage 17 is controlled so that the pressing force against the workpiece W is constant (step S14). Step S15). As it is, the entire measurement area is scanned by the X-axis stage 19 and the Y-axis stage 18 (step S16). When the entire measurement area has been scanned, the Z-axis stage is switched to the position control system and retracted to the safe position (step S17), and the measurement is terminated.

  Next, a calculation method for coordinate measurement will be described.

  First, the relative positions of the probe housing 4 and the reference mirror holding member 22 are measured by the X1 interferometer 13, the X2 interferometer 11, the Z interferometer 16, the Y1 interferometer, and the Y2 interferometer. The relative position between the probe housing 4 and the probe shaft 2 is measured by an X1 displacement meter 6a, an X2 displacement meter 6b, a Y1 displacement meter, a Y2 displacement meter, and a Z displacement meter 7. The outputs of the X1 interferometer 13, X2 interferometer 11, Z interferometer 16, Y1 interferometer, and Y2 interferometer are mx1, mx2, my1, my2, and mz, respectively. The outputs of the X1 displacement meter 6a, the X2 displacement meter 6b, the Y1 displacement meter, the Y2 displacement meter, and the Z displacement meter 7 are denoted by px1, px2, py1, py2, and pz, respectively.

  The relative positions of the center of the probe sphere 1 and the X reference mirror 20, the Y reference mirror, and the Z reference mirror 21 in consideration of tilt errors in the X axis stage 19 and the Y axis stage 18 in directions other than the X direction and other than the Y direction are as follows: , Represented by M below. When the distance from the center position of the X1 interferometer 13, the X2 interferometer 11, and the probe sphere 1 and the distance from the center position of the Y1 interferometer, Y2 interferometer, and probe sphere 1 are 11 and 12, respectively.

  The relative position P between the probe housing 4 and the center of the probe ball 1 takes into account the inclination of the probe shaft 2, and the distance between the X1 displacement meter 6a, the X2 displacement meter 6b, the center position of the probe ball 1, the Y1 displacement meter, Y2 When the distance from the center position of the displacement meter and probe ball 1 is m1 and m2,

と表現されるので、Ｘ基準ミラー２０、Ｙ基準ミラー、Ｚ基準ミラー２１とプローブ球１中心との相対位置を測定座標Ｇは、以下のように表現される。

Therefore, the measurement coordinates G are expressed as follows with respect to the relative positions of the X reference mirror 20, the Y reference mirror, the Z reference mirror 21, and the center of the probe sphere 1.

  Next, a method for setting rigidity and viscosity between the probe housing 4 and the probe shaft 2 will be described.

  For example, the X translation direction, Y translation direction, Z translation direction, X rotation direction, Y rotation direction stiffness, viscosity, respectively,

とするためには、Ｘ、Ｙ、Ｚ力発生機構によって、プローブシャフト２へ下記式で表現される力

To achieve this, the force expressed by the following formula on the probe shaft 2 by the X, Y, Z force generation mechanism

を加えればよい。

Should be added.

これから、上下２箇所でＸ力発生機構、Ｙ力発生機構が発生する力に変換すると、

From now on, when converted into the force generated by the X force generation mechanism and the Y force generation mechanism in two places at the top and bottom,

  Here, Fx1 and Fy1 represent generated forces of the upper X force generating mechanism and Y force generating mechanism, and Fx2 and Fy2 represent generated forces of the lower X force generating mechanism and Y force generating mechanism.

  The force generated by the Z force generation mechanism may be output as it is.

  As shown in FIG. 3, the shape measuring apparatus according to the second embodiment includes a probe composed of a probe ball 1 and a probe shaft 2, and force generating means for generating translational forces in the X and Y directions perpendicular to the probe axis in the Z direction. It has a yoke 3a, a magnetic body 3c, a coil, and the like. These are supported by the probe housing 4. Further, it includes a yoke 5a, a magnet 5b, a coil 5c, which constitute force generating means in the Z direction, and displacement meters 6, 7 which are measuring means.

  The probe shaft 2 is freely arranged with respect to the probe housing 4, and a Z mirror 10 and a probe sphere 1, which is a precision sphere having a very high sphericity, are fixed to the tip of the probe shaft 2. The probe housing 4 is installed on the Z-axis table 15 via the probe base 12 and the support column 14, and the X1 interferometer 13 and the X2 interferometer 11 are arranged on the probe base 12, and the interferometer and the X2 are respectively arranged. The distance from the reference mirror 20 is measured. Further, a Y1 interferometer (not shown) and a Y2 interferometer (not shown) are installed on the probe base 12 and measure the distance from the Y reference mirror (not shown). A Z interferometer 16 is installed on the Z-axis table 15, thereby measuring the distance to the Z reference mirror 21.

  The Z-axis table 15 is connected to a Z-axis stage 17, a Y-axis stage 18, and an X-axis stage 19, and can be operated three-dimensionally by these stages. The amount of movement of the Z-axis table 15 is determined by using the X reference interferometer 13, the X2 interferometer 11, the Y1 interferometer, the Y2 interferometer, and the Z interferometer 16, and the X reference mirror 20, the Y reference mirror, and the Z reference mirror 21. Measure with reference to. The stage is disposed on the base 23, and a reference mirror holding member 22 that holds the X reference mirror 20 and the Z reference mirror 21 is fixed on the base 23 in addition to the above stage. Further, the object to be measured W is fixed so as to be removable.

  An X displacement meter 6 is fixed to the probe housing 4, and this displacement meter measures a relative displacement (translational displacement) in the X direction between the probe housing 4 and the probe shaft 2.

  Although not shown, a Y displacement meter, which is a measuring means for measuring the relative displacement (translational displacement) in the Y direction between the probe housing 4 and the probe shaft 2, is also fixed to the probe housing 4. Further, a Z displacement meter 7 for measuring the relative displacement in the Z direction between the probe housing 4 and the probe shaft 2 is also fixed to the probe housing 4.

  In addition, a force generation mechanism for applying a force from the probe housing 4 to the probe shaft 2 is disposed. A Z force generation mechanism, which is a force generation means for generating a force in the Z direction with respect to the probe shaft 2, includes a yoke 5 a and a coil 5 c fixed to the probe housing 4, and a magnet 5 b fixed to the probe shaft 2. Composed. By applying a current to the coil 5c, the magnetic field density between the magnet 5b and the yoke 5a changes, and a force in the Z vertical direction can be applied to the probe shaft 2.

  An X force generating mechanism that is a force generating means for generating a force in the X direction with respect to the probe shaft 2 includes a yoke 3 a fixed to the probe housing 4 and a magnetic body 3 c fixed to the probe shaft 2. A coil is wound around the yoke 3a, and by passing an electric current through this coil, the attraction force between the yoke 3a and the magnetic body 3c changes, and a force in the X direction acts on the probe shaft 2 Can be made.

  Although not shown, a Y force generation mechanism similar to that in the X direction is also arranged in the Y direction, and force generation means for applying (generating) a force in the Y direction (translational force) to the probe shaft 2 is provided. Configure.

  Next, the signal flow of the apparatus will be described.

  First, there is a main controller (not shown) as the highest level controller of the apparatus. There are three controllers, a measurement controller 24, a stage controller 26, and a force controller 25, as subordinate controllers that receive commands from the main controller.

  The measurement controller 24 determines whether the X1 interferometer 13, the X2 interferometer 11, the Y1 interferometer, the Y2 interferometer, the Z interferometer 16, the X displacement meter 6, the Y displacement meter, and the Z displacement meter 7 based on an instruction from the main controller. Latch displacement data at the same time. Then, the acquired displacement data is transmitted to the main controller.

  The stage controller 26 controls the X-axis stage 19, the Y-axis stage 18, and the Z-axis stage 17 based on an instruction from the main controller. In addition to controlling the position of each stage, Z-axis stage control for keeping the value of the Z displacement meter 7 constant, X-axis stage control for keeping the value of the X displacement meter 6 constant, and the value of the Y displacement meter constant Y axis stage control is performed.

  The force controller 25 controls the generated force of the Z force generating mechanism, the X force generating mechanism, and the Y force generating mechanism from the outputs of the X displacement meter 6 and the Y displacement meter based on an instruction from the main controller.

  Next, a measurement operation performed using the shape measuring apparatus configured as described above will be described with reference to the flowchart of FIG.

  First, the stage controller 26 sets the Z-axis stage 17 to a position control system. That is, control is performed so that the position of the Z-axis stage 17 becomes constant, and then the Z-axis stage 17 is retracted in a safe position, that is, in a direction in which the probe ball 1 is farthest from the workpiece W (step S01).

  Then, the force controller 25 sets the rigidity and viscosity between the probe shaft 2 and the probe housing 4 suitable for measuring the reference surface (end surface) Wb of the workpiece W having the optical surface (surface) Wa ( Step S02).

  For example, the stiffness in the X translation direction and the Y translation direction in the probe ball 1 is set to 10 mN / mm, the viscosity in each direction is set to about 0.7, and the stiffness in the Z translation direction is set to 10 N / mm. With this setting, the reference surface Wb can be measured with a very weak force, and the relative vibration between the probe shaft 2 and the probe housing 4 due to moving stage vibration and other disturbance vibrations is suppressed. .

  The rigidity and viscosity are realized by the X displacement meter 6, the Y displacement meter, the Z displacement meter 7, the X force generation mechanism, the Z force generation mechanism, the Y force generation mechanism, and the force controller 25. Specific control methods Will be described later.

  The X-axis stage 19 and the Y-axis stage 18 are moved so as to be on the measurement point of the first reference plane (step S03).

  Next, the Z-axis stage 17 is lowered so that the height of the probe ball 1 and the reference surface Wb, which is the end surface of the object W to be measured, are matched (step S04).

  Further, the probe sphere 1 is brought close to the reference plane Wb by the X-axis stage 19 and the Y-axis stage 18, and the probe sphere 1 and the reference plane Wb are brought into contact (step S05). The contact between the probe ball 1 and the reference surface Wb can be detected by observing the X displacement meter 6 and the Y displacement meter. That is, when the probe ball 1 is moved from the X plus direction to the X minus direction to approach the reference plane Wb, the output of the X displacement meter 6 touches the minus direction at the time of contact. , Can detect contact.

When the contact is detected, the stage controller 26 controls the X-axis stage 19, the Y-axis stage 18, and the Z-axis stage 17 so that the X displacement meter 6, the Y displacement meter, and the Z displacement meter 7 become constant (step S06). . Then, from the outputs of the X displacement meter 6 , the Y displacement meter, the Z displacement meter 7, the X1 interferometer 13, the X2 interferometer 11, the Y1 interferometer, the Y2 interferometer, and the Z interferometer 16, the coordinates of the measurement point (the coordinate position of the probe) ) Is measured (step S07). The method of calculating the coordinates will be described later.

  After the coordinate measurement, the probe sphere 1 is retracted from the measurement point by the X-axis stage 19 and the Y-axis stage 18 (step S08), and the probe sphere 1 and the object W to be measured are most separated by the Z-axis stage 17. Retreat to a safe position (step S09).

  If the measurement of the reference surface Wb (end surface shape measurement) has been completed, the process proceeds to the optical surface measurement (surface shape measurement). If in the middle, the process returns to step S03 to measure the next reference surface. It performs (step S10).

  When shifting to the measurement of the optical surface Wa, the X-axis stage 19 and the Y-axis stage 18 move to the optical surface measurement start position (step S11). Then, the force controller 25 sets rigidity and viscosity between the probe shaft 2 and the probe housing 4 suitable for optical surface measurement. For example, the stiffness in the X translation direction and the Y translation direction in the probe sphere 1 is set to 200 mN / mm, and the stiffness in the Z translation direction is set to 10 mN / mm (step S12). Thereafter, the probe contact determination mode is set and the Z-axis stage 17 is lowered to bring the probe ball 1 and the optical surface Wa of the workpiece W into contact. Contact between the probe ball 1 and the workpiece W can be detected by monitoring the Z displacement meter 7. That is, when the probe ball 1 and the workpiece W are in contact with each other, the probe shaft 2 is pushed up in the Z + direction, so that the output of the Z displacement meter 7 changes in the + direction, so that the contact can be detected.

  When the probe ball 1 and the workpiece W are in contact, the probe contact determination mode is canceled (step S14), and the needle pressure of the Z-axis stage 17 is controlled so that the pressing force against the workpiece W is constant (step S14). Step S15). As it is, the entire measurement area is scanned by the X-axis stage 19 and the Y-axis stage 18 (step S16). When the entire measurement area has been scanned, the Z-axis stage is switched to the position control system and retracted to the safe position (step S17), and the measurement is terminated.

  Next, a calculation method for coordinate measurement will be described.

  First, the relative positions of the probe housing 4 and the reference mirror holding member 22 are measured by the X1 interferometer 13, the X2 interferometer 11, the Z interferometer 16, the Y1 interferometer, and the Y2 interferometer. The relative position between the probe housing 4 and the probe shaft 2 is measured by an X displacement meter 6, a Y displacement meter, and a Z displacement meter 7. The outputs of the X1 interferometer 13, X2 interferometer 11, Z interferometer 16, Y1 interferometer, and Y2 interferometer are mx1, mx2, my1, my2, and mz, respectively. The outputs of the X displacement meter 6, the Y displacement meter, and the Z displacement meter 7 are assumed to be px2, py2, and pz, respectively.

  The relative positions of the center of the probe sphere 1 and the X reference mirror 20, the Y reference mirror, and the Z reference mirror 21 in consideration of tilt errors in the X axis stage 19 and the Y axis stage 18 in directions other than the X direction and other than the Y direction are as follows: , Represented by M below. When the distance from the center position of the X1 interferometer 13, the X2 interferometer 11, and the probe sphere 1 and the distance from the center position of the Y1 interferometer, Y2 interferometer, and probe sphere 1 are 11 and 12, respectively.

また、プローブハウジング４とプローブ球１中心の相対位置Ｐは、

The relative position P between the probe housing 4 and the center of the probe ball 1 is

と表現されるので、Ｘ基準ミラー２０、Ｙ基準ミラー、Ｚ基準ミラー２１とプローブ球１中心との相対位置を測定座標Ｇは、以下のように表現される。

Therefore, the measurement coordinates G are expressed as follows with respect to the relative positions of the X reference mirror 20, the Y reference mirror, the Z reference mirror 21, and the center of the probe sphere 1.

  Next, a method for setting rigidity and viscosity between the probe housing 4 and the probe shaft 2 will be described.

For example, X translational direction, Y translational direction, the rigidity of the Z translation Direction, viscosity, respectively,

とするためには、Ｘ力発生機構、Ｙ力発生機構、Ｚ力発生機構によって、プローブシャフト２へ下記式で表現される力

To achieve this, the force expressed by the following formula on the probe shaft 2 by the X force generation mechanism, the Y force generation mechanism, and the Z force generation mechanism

を加えればよい。

Should be added.

これから、Ｘ力発生機構、Ｙ力発生機構が発生する力に変換すると、

From now on, when converted into the force generated by the X force generation mechanism and the Y force generation mechanism,

  The force generated by the Z force generation mechanism may be output as it is.

  Example 3 uses the configuration of FIG. The probe shaft 2 is freely arranged with respect to the probe housing 4, and a Z mirror 10 and a probe sphere 1, which is a precision sphere having a very high sphericity, are fixed to the tip of the probe shaft 2. The probe housing 4 is installed on the Z-axis table 15 via the probe base 12 and the support column 14, and the X1 interferometer 13 and the X2 interferometer 11 are arranged on the probe base 12, and the interferometer and the X2 are respectively arranged. The distance from the reference mirror 20 is measured. Further, a Y1 interferometer (not shown) and a Y2 interferometer (not shown) are installed on the probe base 12 and measure the distance from the Y reference mirror (not shown). A Z interferometer 16 is installed on the Z-axis table 15, thereby measuring the distance to the Z reference mirror 21.

  The Z-axis table 15 is connected to a Z-axis stage 17, a Y-axis stage 18, and an X-axis stage 19, and can be operated three-dimensionally by these stages. The amount of movement of the Z-axis table is determined by using the X reference interferometer 13, the X2 interferometer 11, the Y1 interferometer, the Y2 interferometer, and the Z interferometer 16 to set the X reference mirror 20, the Y reference mirror, and the Z reference mirror 21. Measure with reference. The stage is disposed on the base 23, and a reference mirror holding member 22 that holds the X reference mirror 20 and the Z reference mirror 21 is fixed on the base 23 in addition to the above stage. Further, the object to be measured W is fixed so as to be removable.

  An X1 displacement meter 6a and an X2 displacement 6b are fixed to the probe housing 4, and each displacement meter measures a relative displacement in the X direction between the probe housing 4 and the probe shaft 2. . By providing two displacement meters that measure the displacement in the X direction, a measuring means for measuring the posture (rotational displacement) of the probe shaft 2 is configured.

  Although not shown, the Y1 displacement meter and the Y2 displacement meter, which are measuring means for measuring the relative displacement in the Y direction between the probe housing 4 and the probe shaft 2, are also fixed to the probe housing 4. Further, a Z displacement meter 7 for measuring the relative displacement in the Z direction between the probe housing 4 and the probe shaft 2 is also fixed to the probe housing 4.

  The probe housing 4 and the probe shaft 3 are provided with a force generation mechanism that applies a force from the probe housing 4 to the probe shaft 2. A Z force generation mechanism that generates a force in the Z direction with respect to the probe shaft 2 includes a yoke 5 a and a coil 5 c fixed to the probe housing 4 and a magnet 5 b fixed to the probe shaft 2. By applying a current to the coil 5c, the magnetic field density between the magnet 5b and the yoke 5a changes, and a force in the Z vertical direction can be applied to the probe shaft 2.

  An X force generation mechanism that generates a force in the X direction with respect to the probe shaft 2 includes yokes 3 a and 3 b fixed to the probe housing 4 and magnetic bodies 3 c and 3 d fixed to the probe shaft 2. A coil is wound around the yokes 3a and 3b. By passing an electric current through the coils, the attractive force between the yokes 3a and 3b and the magnetic bodies 3c and 3d is changed. A force in the X direction can be applied. The X force generation mechanism is installed at two locations on the top and bottom of the probe shaft 2, and a force generation means for applying (generating) a rotational force to the probe shaft 2 by applying a force by combining these two. Configure. Although not shown, a Y force generation mechanism similar to that in the X direction is also arranged in the Y direction, and a rotational force is applied to the probe shaft 4.

  Next, the signal flow of the apparatus will be described.

  First, there is a main controller as the highest controller of the apparatus. There are three controllers, a measurement controller 24, a stage controller 26, and a force controller 25, as subordinate controllers that receive commands from the main controller.

  Based on an instruction from the main controller, the measurement controller 24 includes an X1 interferometer 13, an X2 interferometer 11, a Y1 interferometer, a Y2 interferometer, a Z interferometer 16, an X1 displacement meter 6a, an X2 displacement meter 6b, a Y1 displacement meter, The displacement data of the Y2 displacement meter and the Z displacement meter 7 are latched simultaneously. Then, the acquired displacement data is transmitted to the main controller.

  The stage controller 26 controls the X-axis stage 19, the Y-axis stage 18, and the Z-axis stage 17 based on an instruction from the main controller. In addition to controlling the position of each stage, Z-axis stage control for making the value of the Z displacement meter 7 constant, X-axis stage control for making the values of the X1 displacement meter 6a and X2 displacement meter 6b constant, Y1 displacement Y-axis stage control is performed to keep the values of the meter and Y2 displacement meter constant.

  Based on an instruction from the main controller, the force controller 25 uses the outputs of the X1 displacement meter 6a, the X2 displacement 6b, the Y1 displacement meter, and the Y2 displacement meter to determine the Z force generation mechanism 5, the X force generation mechanism 3, and the Y force generation mechanism. Control the generated force.

  Next, a measurement operation performed using the shape measuring apparatus configured as described above will be described with reference to the flowchart of FIG.

  First, the stage controller 26 sets the Z-axis stage 17 to a position control system. That is, control is performed so that the position of the Z-axis stage 17 becomes constant, and then the Z-axis stage 17 is retracted in a safe position, that is, in a direction in which the probe ball 1 is farthest from the workpiece W (step S01).

  Then, the force controller 25 sets the rigidity and viscosity between the probe shaft 2 and the probe housing 4 suitable for measuring the reference surface (end surface) Wb of the workpiece W having the optical surface (surface) Wa ( Step S02).

  For example, in the probe ball 1, the rigidity in the X rotation direction and the Y rotation direction is set to 10 mN / mm, the viscosity in each direction is set to about 0.7, and the rigidity in the Z translation direction is set to 10 N / mm. With this setting, the reference surface Wb can be measured with a very weak force, and the relative vibration between the probe shaft 2 and the probe housing 4 due to moving stage vibration and other disturbance vibrations is suppressed. .

  The rigidity and viscosity are realized by the X1 displacement meter 6a, the X2 displacement meter 6b, the Y1 displacement meter, the Y2 displacement meter, the Z displacement meter 7, the X force generation mechanism, the Z force generation mechanism, the Y force generation mechanism, and the force controller 25. However, a specific control method will be described later.

  The X-axis stage 19 and the Y-axis stage 18 are moved so as to be on the measurement point of the first reference plane (step S03).

  Next, the Z-axis stage 17 is lowered so that the height of the probe ball 1 and the reference surface Wb, which is the end surface of the object W to be measured, are matched (step S04).

  Further, the probe sphere 1 is brought close to the reference plane Wb by the X-axis stage 19 and the Y-axis stage 18, and the probe sphere 1 and the reference plane Wb are brought into contact (step S05). The contact between the probe ball 1 and the reference surface Wb can be detected by observing the X1 displacement meter 6a, the X2 displacement meter 6b, the Y1 displacement meter, and the Y2 displacement meter. That is, when the probe ball 1 is moved from the X plus direction to the X minus direction to approach the reference plane Wb, the outputs of the X1 displacement meter 6a and the X2 displacement meter 6b touch the minus direction at the time of contact. By detecting this, contact can be detected.

  When contact is detected, the stage controller 26 controls the X-axis stage 19, the Y-axis stage 18, and the Z-axis so that the X1 displacement meter 6a, X2 displacement meter 6b, Y1 displacement meter, Y2 displacement meter, and Z displacement meter 7 become constant. The stage 17 is controlled (step S06). From the outputs of the X1 displacement meter 6a, X2 displacement meter 6b, Y1 displacement meter, Y2 displacement meter, Z displacement meter 7, X1 interferometer 13, X2 interferometer 11, Y1 interferometer, Y2 interferometer, Z interferometer 16 The coordinates of the measurement point are measured (step S07). The method of calculating the coordinates will be described later.

  After the coordinate measurement, the probe sphere 1 is retracted from the measurement point by the X-axis stage 19 and the Y-axis stage 18 (step S08), and the probe sphere 1 and the object W to be measured are most separated by the Z-axis stage 17. Retreat to a safe position (step S09).

  If the measurement of the reference surface Wb (end surface shape measurement) has been completed, the process proceeds to the optical surface measurement (surface shape measurement). If in the middle, the process returns to step S03 to measure the next reference surface. It performs (step S10).

  When shifting to the measurement of the optical surface Wa, the X-axis stage 19 and the Y-axis stage 18 move to the optical surface measurement start position (step S11). Then, the force controller 25 sets rigidity and viscosity between the probe shaft 2 and the probe housing 4 suitable for optical surface measurement. For example, the rigidity in the X rotation direction and the Y rotation direction in the probe ball 1 is set to 200 mN / mm, and the rigidity in the Z translation direction is set to 10 mN / mm (step S12). Thereafter, the probe contact determination mode is set and the Z-axis stage 17 is lowered to bring the probe ball 1 and the optical surface Wa of the workpiece W into contact. Contact between the probe ball 1 and the workpiece W can be detected by monitoring the Z displacement meter 7. That is, when the probe ball 1 and the workpiece W are in contact with each other, the probe shaft 2 is pushed up in the Z + direction, so that the output of the Z displacement meter 7 changes in the + direction, so that the contact can be detected.

  When the probe ball 1 and the workpiece W are in contact, the probe contact determination mode is canceled (step S14), and the needle pressure of the Z-axis stage 17 is controlled so that the pressing force against the workpiece W is constant (step S14). Step S15). As it is, the entire measurement area is scanned by the X-axis stage 19 and the Y-axis stage 18 (step S16). When the entire measurement area has been scanned, the Z-axis stage is switched to the position control system and retracted to the safe position (step S17), and the measurement is terminated.

  Next, a calculation method for coordinate measurement will be described.

  First, the relative positions of the probe housing 4 and the reference mirror holding member 22 are measured by the X1 interferometer 13, the X2 interferometer 11, the Z interferometer 16, the Y1 interferometer, and the Y2 interferometer. The relative position between the probe housing 4 and the probe shaft 2 is measured by an X1 displacement meter 6a, an X2 displacement meter 6b, a Y1 displacement meter, a Y2 displacement meter, and a Z displacement meter 7. The outputs of the X1 interferometer 13, X2 interferometer 11, Z interferometer 16, Y1 interferometer, and Y2 interferometer are mx1, mx2, my1, my2, and mz, respectively. The outputs of the X1 displacement meter 6a, the X2 displacement meter 6b, the Y1 displacement meter, the Y2 displacement meter, and the Z displacement meter 7 are denoted by px1, px2, py1, py2, and pz, respectively.

  The relative positions of the center of the probe sphere 1 and the X reference mirror 20, the Y reference mirror, and the Z reference mirror 21 in consideration of tilt errors in the X axis stage 19 and the Y axis stage 18 in directions other than the X direction and other than the Y direction are as follows: , Represented by M below. When the distance from the center position of the X1 interferometer 13, the X2 interferometer 11, and the probe sphere 1 and the distance from the center position of the Y1 interferometer, Y2 interferometer, and probe sphere 1 are 11 and 12, respectively.

  The relative position P between the probe housing 4 and the center of the probe ball 1 takes into account the inclination of the probe shaft 2, and the distance between the X1 displacement meter 6a, the X2 displacement meter 6b, the center position of the probe ball 1, the Y1 displacement meter, Y2 When the distance from the center position of the displacement meter and probe ball 1 is m1 and m2,

と表現されるので、Ｘ基準ミラー２０、Ｙ基準ミラー、Ｚ基準ミラー２１とプローブ球１中心との相対位置を測定座標Ｇは、以下のように表現される。

Therefore, the measurement coordinates G are expressed as follows with respect to the relative positions of the X reference mirror 20, the Y reference mirror, the Z reference mirror 21, and the center of the probe sphere 1.

  Next, a method for setting rigidity and viscosity between the probe housing 4 and the probe shaft 2 will be described.

  For example, the rigidity and viscosity in the Z translation direction, X rotation direction, and Y rotation direction are

とするためには、Ｘ力発生機構、Ｙ力発生機構、Ｚ力発生機構によって、プローブシャフト２へ下記式で表現される力

To achieve this, the force expressed by the following formula on the probe shaft 2 by the X force generation mechanism, the Y force generation mechanism, and the Z force generation mechanism

を加えればよい。

Should be added.

これから、Ｘ力発生機構、Ｙ力発生機構が発生する力に変換すると、

From now on, when converted into the force generated by the X force generation mechanism and the Y force generation mechanism,

Here, Fx1 and Fy1 represent generated forces of the upper X force generating mechanism and Y force generating mechanism, and Fx2 and Fy2 represent generated forces of the lower X force generating mechanism and Y force generating mechanism.
The force generated by the Z force generation mechanism may be output as it is.

1 is a schematic diagram showing a shape measuring apparatus according to Example 1. FIG. It is a flowchart which shows a shape measurement flow. 6 is a schematic diagram showing a shape measuring apparatus according to Embodiment 2. FIG. It is a figure explaining a prior art example. It is a figure explaining another prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Probe ball 2 Probe shaft 3a, 3b Yoke 3c, 3d Magnetic body 4 Probe housing 5a Yoke 5b Magnet 5c Coil 6 X displacement meter 6a X1 displacement meter 6b X2 displacement meter 7 Z displacement meter 10 Z mirror 11 X2 interferometer 12 Probe base 13 X1 Interferometer 14 Post 15 Z-axis Table 16 Z Interferometer 17 Z-axis Stage 18 Y-axis Stage 19 X-axis Stage 20 X Reference Mirror 21 Z Reference Mirror 22 Reference Mirror Holding Member 23 Base 24 Measurement Controller 25 Force Controller 26 Stage Controller

Claims (9)

A device having a probe housing that can be moved three-dimensionally, and a probe that is held so as to be movable relative to the probe housing, and performing the scanning control of the probe with respect to the surface of the device to be measured. In the shape measuring device for measuring the coordinate position of the probe representing the surface shape of
Measuring means for measuring a translational displacement, which is a relative displacement of the probe with respect to the probe housing in a direction perpendicular to the longitudinal direction of the probe ;
Force generating means arranged in one place with respect to the longitudinal direction of the probe for generating a translational force on the probe ;
The probe and the probe are controlled by controlling the translation force by the force generation means based on the output of the measurement means and changing the translation force between the surface measurement of the object to be measured and the end face measurement of the object to be measured. A shape measuring device comprising: means for setting rigidity and viscosity between the housing and the housing . The axial direction of the probe is the Z direction, and the directions perpendicular to the Z direction are the X direction and the Y direction,
The means for changing the translation force is more rigid in the X translation direction and the Y translation direction in the case of measuring the end face of the measurement object than in the X translation direction and the Y translation direction in the measurement of the surface of the measurement object. The translational force is changed between the surface measurement of the object to be measured and the end surface measurement of the object to be measured by controlling the translational force by the force generating means based on the set rigidity. The shape measuring apparatus according to claim 1.   The probe is brought into contact with the end face of the object to be measured, and the probe is moved along the end face while controlling the translational force by the force generating means based on the output of the measuring means, and the end face of the object to be measured 3. The shape measuring apparatus according to claim 1, wherein the coordinate position of the probe representing the shape is measured. A device having a probe housing that can be moved three-dimensionally, and a probe that is held so as to be movable relative to the probe housing, and performing the scanning control of the probe with respect to the surface of the device to be measured. In the shape measuring device for measuring the coordinate position of the probe representing the surface shape of
Measuring means for measuring a rotational displacement, which is a relative displacement of the probe in two locations in the longitudinal direction in a direction perpendicular to the longitudinal direction of the probe, with respect to the probe housing;
Force generating means disposed at two different positions with respect to the longitudinal direction of the probe for generating a rotational force with respect to the probe ;
The probe and the probe are controlled by controlling the rotational force by the force generating means based on the output of the measuring means and changing the rotational force between the surface measurement of the object to be measured and the end face measurement of the object to be measured. A shape measuring device comprising: means for setting rigidity and viscosity between the housing and the housing . The axial direction of the probe is the Z direction, and the directions perpendicular to the Z direction are the X direction and the Y direction,
The means for changing the rotational force is more rigid in the X rotation direction and Y rotation direction in the case of measuring the end surface of the measurement object than in the X rotation direction and Y rotation direction in the case of measuring the surface of the measurement object. Is set small, and the rotational force by the force generation means is controlled based on the set rigidity, thereby changing the rotational force between the surface measurement of the object to be measured and the end face measurement of the object to be measured. The shape measuring apparatus according to claim 4.   The probe is brought into contact with the end face of the object to be measured, and the probe is moved along the end face while controlling the rotational force by the force generating means based on the output of the measuring means, and the end face of the object to be measured 6. The shape measuring apparatus according to claim 4, wherein the coordinate position of the probe representing the shape is measured. A device having a probe housing that can be moved three-dimensionally, and a probe that is held so as to be movable relative to the probe housing, and performing the scanning control of the probe with respect to the surface of the device to be measured. In the shape measuring device for measuring the coordinate position of the probe representing the surface shape of
Translational displacement of the probe relative to the probe housing in a direction perpendicular to the longitudinal direction of the probe, and relative displacement at two locations in the longitudinal direction in the direction perpendicular to the longitudinal direction of the probe measuring means for measuring the rotational displacement is,
Force generating means arranged at two different positions with respect to the longitudinal direction of the probe for generating a translational force and a rotational force with respect to the probe ;
Based on the output of the measuring means, to control the translational force and rotational force by said force generating means, wherein changing the translational force and rotational force in the end face measurement of said object to be measured and the surface measurement of the object to be measured And a means for setting rigidity and viscosity between the probe and the probe housing . The axial direction of the probe is the Z direction, and the directions perpendicular to the Z direction are the X direction and the Y direction,
The means for changing the rotational force is more suitable in the case of measuring the end face of the object to be measured than the rigidity in the X translation direction, the Y translation direction, the X rotation direction, and the Y rotation direction in the case of measuring the surface of the object to be measured. By setting the rigidity in the X translation direction, the Y translation direction, the X rotation direction, and the Y rotation direction to be small, and controlling the translation force and the rotation force by the force generating means based on the set rigidity, the device under test is measured. The shape measuring apparatus according to claim 7, wherein the translational force and the rotational force are changed between the surface measurement and the end face measurement of the object to be measured.   The probe is brought into contact with the end face of the object to be measured, and the probe is moved along the end face while controlling the translational force and the rotational force by the force generating means based on the output of the measuring means, and the measured object 9. The shape measuring apparatus according to claim 7, wherein a coordinate position of the probe representing an end face shape of an object is measured.

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