JP2014149247A - Measurement method, determination method, and measurement instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique which is advantageous to obtain an apex in a detection object surface when measuring a shape of the detection object surface.SOLUTION: A measurement method for measuring a shape of a detection object surface by causing a probe to scan relatively to the detection object surface in a state where a front end of the probe is in contact with the detection object surface includes: a contact step of bringing the front end of the probe into contact with the detection object surface; a setting step of setting a line including a route along which the front end of the probe is moved on the detection object surface when being brought into contact with the detection object surface, as a scan route for the probe scanning relative to the detection object surface; an acquisition step of causing the probe to scan along the scan route and acquiring position information at a plurality of measurement points on the scan route; and a determination step of determining the shape of the detection object surface on the basis of the position information on the scan route.

Description

  The present invention relates to a measurement method, a determination method, and a measurement apparatus.

  2. Description of the Related Art Contact-type measuring devices that measure the surface shapes of lenses, mirrors, prisms, and their molds while bringing the tip of a probe into contact with a test surface (surface) are known. The contact-type measuring device scans the probe relative to the surface to be measured while the tip of the probe is in contact with the surface to be detected, and detects the displacement of the probe at that time by a laser length measuring device or the like. Thus, the shape of the test surface can be measured.

  In such a contact-type measuring apparatus, it is required to set a plurality of paths for scanning the test surface with the probe so as to be symmetric with respect to the path including the vertex of the test surface. Therefore, when measuring the shape of the test surface, it is necessary to obtain the position of the vertex on the test surface. In view of this, Patent Document 1 proposes a method for obtaining the position of the apex of the test surface in a contact-type measuring apparatus. In Patent Document 1, a plurality of paths for scanning a test surface by a probe are set on the test surface so that they are parallel to each other, and the radius of curvature in each path is set by scanning the probe along each path. It is determined. And the position of the vertex in a to-be-tested surface is calculated | required based on the curvature radius determined in each path | route.

JP 2007-271359 A

  In the measuring apparatus described in Patent Document 1, the position of the vertex on the test surface is determined by repeating the step of bringing the probe into contact with the test surface and the step of scanning the probe in contact with the test surface. Looking for. For this reason, it takes a considerable time to obtain the position of the vertex on the surface to be examined. In particular, when the probe is brought into contact with the test surface, a gentle contact operation is required to prevent damage to the probe or damage to the test surface, and the process of bringing the probe into contact with the test surface is repeated. Will take much time.

  Therefore, an object of the present invention is to provide a technique that is advantageous in obtaining the apex on the test surface when measuring the shape of the test surface.

  In order to achieve the above object, a measurement method according to one aspect of the present invention is configured to scan the probe relative to the test surface in a state where the tip of the probe is in contact with the test surface. A measuring method for measuring a shape of a test surface, wherein a contact step of bringing the tip of the probe into contact with the test surface, and the tip of the probe being brought into contact with the test surface when the tip of the probe is brought into contact with the test surface A setting step of setting a line including a path moved on a surface as a scanning path when the probe is scanned relative to the test surface; and scanning the probe along the scanning path; An acquisition step of acquiring position information at a plurality of measurement points on the scanning path; and a determination step of determining the shape of the test surface based on the position information on the scanning path. .

  According to the present invention, for example, when measuring the shape of the test surface, it is possible to provide a technique that is advantageous in obtaining the vertex on the test surface.

It is a figure which shows the measuring apparatus of 1st Embodiment of this invention. It is a figure for demonstrating the force added to a probe when a probe is made to contact a test surface. It is a figure when the inside of the probe housing in the state which the probe inclined is seen from the Z direction. It is a flowchart which shows the method of measuring the shape of a to-be-tested surface in the measuring apparatus of 1st Embodiment. It is a figure which shows the scanning path | route of the probe on a to-be-tested surface. It is a figure which shows the scanning path | route of the probe on a to-be-tested surface. It is a figure which shows the scanning path | route of the probe on the surface of a cylindrical lens.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the accompanying drawings. In addition, in each figure, the same reference number is attached | subjected about the same member thru | or element, and the overlapping description is abbreviate | omitted.

<First Embodiment>
A measuring apparatus 1 according to a first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a diagram illustrating a measuring apparatus 1 according to the first embodiment. The measuring apparatus 1 according to the first embodiment includes a probe 4, a probe housing 6 that elastically supports the probe 4, and a drive unit 13 that drives the probe housing 6. The measuring apparatus 1 includes a control unit 14 that controls the movement of the probe 4 and controls the measurement of the shape of the test surface. The measuring apparatus 1 can measure the shape of the test surface by causing the probe 4 to scan relative to the test surface with the tip of the probe 4 in contact with the test surface.

  The probe 4 includes a probe ball 2 and a probe shaft 3. The probe sphere 2 is a precision sphere with a high sphericity provided at the tip of the probe shaft 3 on the test surface side, and is a portion that comes into contact with the test surface when measuring the shape of the test surface. The probe 4 is elastically supported by the probe housing 6 via the elastic support member 5. The probe housing 6 has a first detector 7x and a second detector 7y. The first detection unit 7x detects a first tilt amount that is an amount by which the probe 4 is tilted in the X direction (first direction) when the tip of the probe 4 (probe sphere 2) contacts the test surface. Further, the second detection unit 7y detects a second tilt amount, which is an amount by which the probe 4 is tilted in the Y direction (second direction) when the probe sphere 2 comes into contact with the test surface.

First detector 7x is arranged in the X direction within the probe housing 6, for example, a plurality of displacement gauges which are spaced apart in the Z direction (the two displacement meters in the first embodiment (7x ₁ and 7x ₂₎ )including. The first detector 7x, based on the displacement amount in the X-direction of the probe 4 detected by the displacement sensor 7x _1, the displacement amount in the X-direction of the probe 4 detected by the displacement gauge 7x ₂ probe The first inclination amount of 4 can be detected. Displacement meter 7x ₁ and 7x _2, for example capacitive sensor is configured to include each between the capacitance change between the probe 4 and the displacement meter 7x _1, and the probe 4 and the displacement gauge 7x ₂ Each change in capacity is measured. Thus, displacement meter 7x ₁ and 7x ₂ can detect the displacement amount in the X-direction of the probe 4 respectively. In displacement meter 7x ₁ and 7x ₂ of the first embodiment, are configured to include a capacitance sensor, it is not limited thereto, configured to detect the amount of displacement of the probe 4 with high precision It only has to be done.

Similarly, the second detection unit 7y is placed on the Y direction side of the probe housing 6, for example, a plurality of displacement gauges which are spaced apart in the Z direction (in the first embodiment two displacement meter (7y ₁ and 7y ₂ )). Then, the second detection unit 7y, the probe 4 on the basis of the displacement amount in the Y direction of the detection probe by the displacement gauge 7y _1, the displacement amount in the Y direction of the probe 4 detected by the displacement gauge 7y ₂ The second inclination amount can be detected. The displacement meters 7y ₁ and 7y ₂ are configured to include, for example, capacitance sensors, respectively, and change in capacitance between the probe and the displacement meter 7y ₁ and change in capacitance between the probe and the displacement meter 7y _2. Measure each. Thus, displacement meter 7y ₁ and 7y ₂ can detect the displacement amount in the Y direction of the probe 4 respectively.

  In addition, the probe housing 6 has a third detection unit 7z that detects the displacement of the probe 4 in the Z direction. The third detector 7z includes a displacement meter disposed on the surface of the probe housing 6 on the Z direction side. The displacement meter includes, for example, a capacitance sensor, and can detect a displacement amount of the probe 4 in the Z direction by measuring a capacitance change between the probe and the displacement meter. Here, the displacement meter included in the first detection unit 7x, the second detection unit 7y, and the third detection unit 7z is configured to include a capacitance sensor, but is not limited thereto. It is only necessary that the displacement amount 4 can be detected with high accuracy.

  The drive unit 13 is disposed on the base 16 and is provided to drive the probe housing 6. The drive unit 13 includes, for example, a top plate 13a that supports the probe housing 6, a Z-axis stage 13b that drives the top plate 13a in the Z direction, a Y-axis stage 13c that drives the top plate 13a in the Y direction, and a top plate It is constituted by an X axis stage 13d that drives 13a in the X direction. Thus, the probe housing 6 can be moved in three axial directions (three-dimensionally), and the probe 4 elastically supported by the probe housing 6 is brought into contact with the test surface of the test object W arranged on the base 16. In this state, scanning can be performed relative to the test surface.

The probe housing 6, the interferometer 9x ₁ and 9x ₂ for measuring the X position of the probe housing 6 is provided. Each interferometer 9x ₁ and 9x _2, for example, the probe is irradiated with laser light to the X reference mirror 10 supported by the structure 17 which is connected to the base 16, the laser beam reflected by the X reference mirror 10 The displacement from the reference position in the housing 6 is detected. Thereby, the distance between the X reference mirror 10 and the probe housing 6, that is, the position of the probe housing 6 in the X direction can be measured. Similarly, the probe housing 6, the interferometer 9y ₁ and 9y 2 _(not shown) for measuring the position in the Y direction of the probe housing 6, the interferometer 9z for measuring the position in the Z direction of the probe housing 6 Is provided. Each of the interferometers 9y ₁ and 9y ₂ irradiates a laser beam toward a Y reference mirror (not shown) supported by a structure 17 connected to the base 16, and reflects the laser beam reflected by the Y reference mirror. Thus, the displacement from the reference position in the probe housing 6 is detected. Thereby, the distance between the Y reference mirror and the probe housing 6, that is, the position of the probe housing 6 in the Y direction can be measured. For example, the interferometer 9z irradiates laser light toward the Z reference mirror 12 supported by the structure 17 connected to the base 16, and the reference position in the probe housing 6 is reflected by the laser light reflected by the Z reference mirror 12. The displacement from is detected. Thereby, the distance between the Z reference mirror 12 and the probe housing 6, that is, the position of the probe housing 6 in the Z direction can be measured.

  In the measuring apparatus 1 configured in this way, depending on the shape of the object to be measured, a plurality of paths for scanning the test surface by the probe are set so as to be symmetric with respect to the path including the vertex of the test surface. Is required. For example, when measuring a rotationally symmetric test object having a vertex such as a convex lens, it is necessary to determine the position of the vertex of the test surface. Therefore, it is necessary to set the scanning path of the probe so as to include the vertex of the test surface. Therefore, the control unit 14 indicates a line including a path along which the tip of the probe 4 (probe ball 2) moves on the test surface when the probe 4 is brought into contact with the test surface. And set as a scanning path for relatively scanning. For example, when the probe ball 2 is brought into contact with a portion having an inclination on the test surface, the probe ball 2 moves according to the inclination, and the probe 4 is inclined with the elastic support member 5 as a fulcrum. Thus, when the probe sphere 2 moves according to the inclination of the test surface, the apex of the test surface in the direction opposite to the direction in which the probe sphere 2 moves (the direction in which the probe 4 (probe shaft 3) tilts). Will be located. Therefore, when a line including a path on which the probe sphere 2 moves on the test surface is set as the scanning path of the probe, the vertex of the test surface can be included in the scanning path. That is, the probe 4 can be scanned so as to pass through the apex of the test surface. In addition, the control unit 14 acquires position information at a plurality of measurement points on the set scanning path, and determines the shape of the test surface based on the acquired position information.

  Here, the principle that the probe 4 tilts when the probe 4 is brought into contact with the test surface of the test object W will be described with reference to FIG. FIG. 2A shows the relationship between the force applied to the probe sphere 2 and the force applied to the probe shaft 3 when the probe sphere 2 is brought into contact with the inclined portion p of the test surface. It is. When the probe ball 2 is brought into contact with the portion p on the test surface, the point q on the probe shaft 3 pushes the probe shaft 3 in the −Z direction due to the rigidity of the elastic support member 5 (Z-axis needle pressure). ) Fz and a force (restraint force) Fr for restraining the probe shaft 3 are generated. Therefore, a resultant force Fb that is a force obtained by combining the Z-axis needle pressure Fz and the restraining force Fr is generated at the point q on the probe shaft 3. The probe ball 2 generates a vertical drag Fn from the portion p and a frictional force Fx between the test surface and the probe ball 2 due to the Z-axis needle pressure Fz. Therefore, a resultant force Fa that is a force obtained by synthesizing the normal force Fn and the frictional force Fx is generated in the probe ball 2 from the portion p. When the friction between the probe ball 2 and the test surface is small, such as an optical lens or a mold, the resultant force Fa is approximately the same direction and magnitude as the thrust drag Fn, and the resultant force Fb The opposite direction. Further, the resultant force Fb is in a positional relationship offset (shifted) to the left as viewed from the resultant force Fa, so that a moment N is generated in the probe ball 2 in the counterclockwise direction. The probe 4 is affected by the moment N generated in the probe sphere 2 and tilts so that the probe sphere 2 moves in the X direction with the point q as a fulcrum.

  When the test object W is rotationally symmetric about the vertex O as shown in FIG. 2B, the Z-axis needle pressure Fz, the restraining force Fr, the vertical drag Fn, and the friction force Fx described above are It occurs on the surface P including the vertex O of the inspection surface. Therefore, since the resultant force Fa and the resultant force Fb are also generated on the surface P, the probe ball 2 moves along the surface P, and the probe 4 tilts along the surface P. That is, the line on the test surface including the path along which the probe sphere 2 has moved when the probe sphere 2 is brought into contact with the portion p on the test surface is a line 21 where the test surface and the surface P intersect. Then, by setting the line 21 as the scanning path of the probe 4, the probe 4 can be scanned so as to pass through the vertex of the test surface. As described above, such a scanning path includes the first inclination amount of the probe 4 detected by the first detection unit 7x provided in the probe housing 6 and the first inclination amount of the probe 4 detected by the second detection unit 7y. It is determined by the control unit 14 based on the two inclination amounts.

Next, a method for determining a scanning path based on the first inclination amount and the second inclination amount will be described with reference to FIGS. 1 and 3. FIG. 3A is a diagram when the inside of the probe housing 6 is viewed from the Z direction in a state where the probe ball 2 is in contact with the surface to be measured and the probe 4 is tilted. As described above, the probe housing 6 includes the first detection unit 7x and the second detection unit 7y. The first detector 7x is a displacement gauge 7x ₁ and displacement gauge 7x ₂ are spaced apart in the Z-direction, the second detection section 7y displacement gauge 7y ₁ and displacement gauge disposed apart in the Z-direction 7y ₂ Respectively.

Displacement meter 7x _1, in position in the Z direction displacement meter 7x ₁ is arranged to measure the X-direction distance px1 the displacement meter 7x ₁ and the probe 4 (the probe shaft 3). For example, displacement meter 7x ₁ is relative to the position of the X-direction of the probe 4 in the state in which nothing comes into contact with the probe ball 2 on the test surface (non-contact state), a state where the probe ball 2 is brought into contact with the test surface (contact The displacement amount in the X direction of the probe 4 in the state) is measured. The amount of displacement, by adding the X direction distance between the displacement gauge 7x ₁ and the probe 4 in the case of a non-contact state (reference distance), the X direction and the displacement gauge 7x ₁ and the probe 4 at the time of contact The distance px1 can be measured. Similarly, displacement gauge 7x _2, in position in the Z direction displacement gauge 7x ₂ are disposed, it is possible to measure the X-direction distance px2 the displacement meter 7x ₂ and the probe 4 at the time of contact . Thereby, the 1st detection part 7x can detect the 1st inclination amount which is the quantity which the probe 4 inclined in the X direction (1st direction).

Displacement meter 7y _1, in position in the Z direction displacement meter 7y ₁ is arranged to measure the Y-direction distance py1 between the displacement gauge 7y ₁ and the probe 4. For example, displacement meter 7y ₁ is the Y-direction position of the probe 4 when the non-contact state, to measure the displacement amount in the Y direction of the probe 4 when the contact state. The amount of displacement, by adding the Y direction distance between the displacement sensor 7y ₁ and the probe 4 in the case of a non-contact state (reference distance), Y direction distance between the displacement sensor 7y ₁ and the probe at the time of the contact py1 can be measured. Similarly, displacement gauge 7y _2, in position in the Z direction displacement gauge 7y ₂ are disposed, it is possible to measure the Y-direction distance py2 between the displacement gauge 7y ₂ and the probe 4 at the time of contact . Thereby, the 2nd detection part 7y can detect the 2nd inclination amount which is the quantity which the probe 4 inclined in the Y direction (2nd direction).

Based on the first tilt amount detected by the first detection unit and the second tilt amount detected by the second detection unit, the control unit 14 detects the probe when the probe ball 2 is brought into contact with the test surface. A direction A in which 4 is inclined (a direction opposite to the direction in which the probe ball 2 has moved) is obtained by the equation (1). Based on this direction A, the control unit 14 determines a scanning path when the probe 4 scans relative to the surface to be examined. Thereby, the determined scanning path can be made to include the vertex of the test surface. Here, the measuring apparatus 1 of the first embodiment, a displacement meter 7x ₁ and displacement gauge 7y ₁ is disposed at the same position in the Z direction, and displacement sensors 7x ₂ and displacement gauge 7y ₂ is Z-direction In the same position. In the present embodiment, as shown in FIG. 3A, the probe housing 6 is provided with the first detection unit 7x and the second detection unit 7y. However, as illustrated in FIG. 3B, the structure 17 may include the first detection unit 7 x and the second detection unit 7 y.
A = [(px1-px2), (py1-py2)] (1)

  A method of measuring the shape of the test surface in the measuring apparatus 1 configured as described above will be described with reference to FIGS. 4 and 5. FIG. 4 is a flowchart showing a method for measuring the shape of the test surface in the measurement apparatus 1 of the first embodiment, and FIG. 5 is a diagram showing the scanning path of the probe 4 on the test surface. Here, a convex lens is assumed as the test object W.

  First, before starting the flowchart shown in FIG. 4, the measurement apparatus 1 is turned on and the system of the apparatus is started, and the object W is placed in the measurement apparatus (on the base 16). Immediately after the power is turned on, the temperature in the apparatus varies greatly, which may affect the measurement accuracy, etc. Therefore, measurement should be started after a certain time has elapsed since the power was turned on. Further, before starting the measurement, a measurement sequence such as a measurement location is set according to the information on the test object W and the portion to be measured. In S <b> 1, the control unit 14 controls the drive unit 13 to move the probe 4 from the retracted position to above the test object W. In S2, the control unit 14 stands by until a command to start measurement is supplied. If a command to start measurement is supplied, the process proceeds to S3. In S3, the control unit 14 controls the drive unit 13 to move the probe 4 in the −Z direction, and brings the tip of the probe 4 (probe sphere 2) into contact with the surface to be measured. At this time, for example, as shown in FIG. 5A, the probe sphere 2 is brought into contact with a portion p on the test surface that is at a position away from the apex of the test surface and has an inclination. For example, the probe ball 2 may be brought into contact with the portion p on the test surface having a large curvature. When the probe sphere 2 is brought into contact with the inclined portion p in this way, the probe 4 is greatly inclined, so that it is easy to detect the direction in which the probe 4 is inclined and set the scanning path of the probe 4. On the other hand, when the probe is brought into contact with a portion on the test surface with a small inclination, such as the vertex O of the test surface, the probe 4 hardly tilts, and it becomes difficult to set the scanning path of the probe 4. It can happen.

  In S4, the control unit 14 moves the probe 4 relative to the test surface so that the probe ball 2 includes a path on the test surface when the probe ball 2 is brought into contact with the test surface. A scanning path m1 for scanning is set. As described above, the scanning path m1 of the probe 4 is directed toward the direction in which the probe 4 is inclined when the probe sphere 2 is brought into contact with the test surface (the direction opposite to the direction in which the probe sphere 2 moves). Is set to scan. The direction in which the probe 4 is tilted is, as described above, the first tilt amount detected by the first detector 7x (the amount by which the probe is tilted in the X direction) and the second detector 7y detected by the second detector 7y. 2 is obtained based on the tilt amount (the amount the probe is tilted in the Y direction). By setting the scanning path m1 of the probe 4 in this way, the scanning path m1 of the probe includes the vertex O of the test surface as shown in FIGS. 5 (a) and 5 (b). The probe 4 can be scanned so as to pass through the vertex O. Here, as shown in FIG. 2B, a plane P including the vertex O and the scanning path m1 is defined as an XZ plane.

  In S5, the control unit 14 controls the driving unit 13 to scan the probe 4 along the scanning path m1 set in S4, and acquires position information at a plurality of measurement points on the scanning path m1. In the first embodiment, the control unit 14 causes the probe 4 to reciprocate and scan along the scanning path m1 as indicated by a broken line arrow 51 in FIG. 5C, for example. By performing reciprocal scanning in this way, for example, an area on the scanning path m1 that does not pass the probe 4 that may occur when the probe 4 is scanned only in a certain direction (for example, −X direction) from the portion p on the test surface. 52 can be reduced. By reciprocating scanning, the same place on the surface to be measured can be measured twice. Here, in the measurement apparatus 1 of the first embodiment, the probe 4 is reciprocally scanned (scanned twice) along the scanning path m1, but the present invention is not limited to this. For example, the probe 4 is moved along the scanning path m1. May be scanned a plurality of times (three or more times).

  The control unit 14 first scans the probe 4 in the direction in which the probe 4 is inclined, that is, in the direction from the portion p on the test surface toward the vertex O (−X direction) (region 53). When the probe sphere 2 passes through the vertex O, the direction in which the probe 4 tilts is the opposite direction. However, even when the probe sphere 2 passes through the vertex O, the control unit 14 is the same as the direction in which the probe is scanned in the region 53. The probe 4 is scanned in the direction (−X direction) (region 54). Then, the control unit 14 scans the probe 4 in the −X direction along the scanning path m <b> 1 until the position of the probe sphere 2 in the Z direction is lower than the position of the vertex O in the Z direction by the distance a. When the position of the probe sphere 2 in the Z direction becomes lower than the position of the vertex O in the Z direction by a distance a, the control unit 14 changes the direction in which the probe 4 is scanned to the opposite direction (X direction) and again scan path m1. The probe 4 is scanned along (toward the vertex O) (region 54). When the probe sphere 2 passes the vertex O, the direction in which the probe 4 tilts becomes the opposite direction (−X direction), but the control unit 14 scans the probe in the region 54 even when the probe sphere 2 passes the vertex O. The probe 4 is scanned in the same direction (X direction) as the direction (region 53). Then, the control unit 14 scans the probe 4 in the X direction along the scanning path m1 until the position of the probe sphere 2 in the Z direction is lower than the position of the vertex O in the Z direction by a distance b. When the position in the Z direction of the probe sphere 2 becomes lower than the position of the vertex O by the distance b, the control unit 14 changes the direction in which the probe is scanned to the opposite direction (−X direction), and again along the scanning path m1. The probe 4 is scanned (toward the vertex O) (region 53 (region 52)). Then, the measurement ends when the probe sphere 2 comes to the portion p. Here, in the first embodiment, the control unit 14 scans the probe 4 in the direction in which the probe 4 is inclined from the portion p on the test surface. For example, the probe 14 starts from the portion p on the test surface. The probe 4 may be scanned in a direction opposite to the direction in which the 4 is inclined. As described above, the measurement sequence such as the direction in which the probe 4 is scanned from the portion p on the test surface is set before the measurement of the test surface is started as described above. In the measurement sequence, in addition to the direction in which the probe 4 is scanned, for example, the number of times the probe 4 is scanned along the scanning path m1, the distance a, the distance b, and the like can be set.

  Thus, when the probe 4 is scanned along the scanning path m1, the control unit 14 acquires position information at a plurality of measurement points on the scanning path m1. For example, the control unit 14 causes each detection unit (7x, 7y, and 7z) to measure the displacement amount of the probe 4 and each interferometer (9x, 9y, and 9z) to measure the position of the probe housing 6 at each measurement location. . And the control part 14 can acquire the position of the probe ball | bowl 2 based on the displacement amount of the probe 4 detected by each detection part, and the position of the probe housing 6 measured by each interferometer. Based on the position of the probe sphere 2, the control unit 14 can acquire position information at each measurement point on the scanning path m 1, that is, position coordinates. Here, when acquiring the position information of each measurement location from the position of the probe sphere 2, the probe 4 is in a state of being inclined according to the inclination at the measurement location. In this state, there is a positional shift between the portion p on the test surface where the test surface and the probe sphere 2 are in contact with the center of the probe sphere 2, so that an error may occur in the position information of each measurement location. . Therefore, the control unit 14 determines the angle at which the probe 4 is tilted based on the first tilt amount detected by the first detector 7x and the second tilt amount detected by the second detector 7y. You may correct | amend the positional information on each measurement location based on an angle. Further, when the probe 4 is relatively scanned along the scanning path m1 a plurality of times, a plurality of pieces of position information at each measurement point are obtained, and an average value of the plurality of pieces of position information obtained at the measurement points is obtained. It is good also as the positional information on the said measurement location. For example, in FIG.5 (c), since the probe 4 passes twice in the measurement location 55, positional information is acquired twice. In this case, the average value of the position information acquired twice at the measurement point 55 is the position information at the measurement point 55.

  In S6, the control unit 14 determines the shape of the test surface based on the position information measured at each measurement location. In the first embodiment, since the probe is merely scanned relatively on the scanning path m1 including the vertex O of the test surface, the shape (cross-sectional shape) of the test surface on the scanning path m1 is determined. . In S <b> 7, the control unit 14 controls the driving unit 13 to move the probe 4 away from the test surface and move the probe 4 from above the test surface to the retracted position.

  As described above, in the measurement apparatus 1 of the first embodiment, the scanning path is set according to the inclination of the probe 4 when the probe 4 is brought into contact with the surface to be measured. That is, when the tip of the probe 4 (probe sphere 2) is brought into contact with the test surface, a line including a path along which the probe sphere 2 has moved on the test surface is shown relative to the probe 4 relative to the test surface. It is set as a scanning path for scanning. By setting the scanning path of the probe 4 in this way, the scanning path includes the apex of the test surface, so that the probe 4 can be scanned through the apex of the test surface.

Second Embodiment
In the second embodiment of the present invention, a case where a plurality of scanning paths are set when the probe 4 is scanned relative to the surface to be examined will be described with reference to FIG. Since the measuring apparatus used in the second embodiment is the same as the measuring apparatus 1 of the first embodiment, description of the measuring apparatus is omitted.

  First, similarly to the flowchart shown in FIG. 4 of the first embodiment, the control unit 14 sets the scanning path m1 according to the inclination of the probe 4 when the probe sphere 2 is brought into contact with the test surface. That is, a scanning path for scanning the probe 4 relative to the test surface with a line including a path in which the probe sphere 2 moves on the test surface when the probe sphere 2 is brought into contact with the test surface. Set as m1. Thereby, since the scanning path m1 of the probe 4 includes the vertex O of the test surface, the probe 4 can be scanned through the vertex of the test surface. Then, the control unit 14 acquires position information at a plurality of measurement points on the scanning path m1.

  Next, as shown in FIG. 6, the control unit 14 sets the second scanning path m2 on the test surface parallel to the scan path m1 including the vertex O of the test surface and separated from the scan path m1 by the distance d. Set. And the control part 14 scans the probe 4 on a to-be-tested surface along the 2nd scanning path | route m2, and acquires position information in the several measurement location on a 2nd scanning path | route. After acquiring the position information at a plurality of measurement points on the second scanning path, the control unit 14 performs a third operation on the test surface parallel to the second scanning path m2 and separated from the second scanning path m2 by the distance d. A scanning path m3 is set. Then, the control unit 14 scans the probe 4 on the surface to be measured along the third scanning path m3, and acquires position information at a plurality of measurement points on the third scanning path. Thus, in the second embodiment, the scanning path for scanning the probe 4 is set in parallel while sequentially shifting by the distance d, and the position information is acquired at a plurality of measurement points in each scanning path. The control unit 14 determines the shape of the test surface based on position information acquired at a plurality of measurement points on each scanning path. Here, the control unit 14 may cause the probe to relatively scan a plurality of times along the second scanning path m2. In this case, a plurality of pieces of position information at each measurement point on the second scanning path may be acquired, and an average value of the plurality of pieces of position information acquired at the measurement point may be used as the position information of the measurement point. The same applies to the third scanning path.

  As described above, in the measuring apparatus according to the second embodiment, the scanning path m1 of the probe 4 is set so as to include the vertex O of the test surface in the same manner as in the first embodiment, and then a plurality of parallel to the scanning path m1 is set. Scanning paths (for example, scanning paths m2 and m3) are set. Then, the shape of the test surface is determined based on position information acquired at a plurality of measurement points on each scanning path. Thereby, the shape of the test surface can be measured three-dimensionally.

  In the present embodiment, a plurality of scanning paths parallel to the scanning path m1 of the probe are set as a method for measuring the shape of the test surface three-dimensionally, but the present invention is not limited to this. A probe ball is brought into contact with a test surface different from the scan path m1, and a scan path including the vertex O of the test surface is set. The cross-sectional shape of the test surface is measured by setting and measuring the scanning path by the method described in the first embodiment. In this way, the shape of the test surface may be measured by setting the scanning path radially from the vertex O.

<Third Embodiment>
In 1st Embodiment and 2nd Embodiment, although the case where the rotationally symmetrical test object W centering on the vertex O, such as a convex lens, was measured was demonstrated, in 3rd Embodiment, the test object W which is not rotationally symmetric. The case of measuring is described. In the third embodiment, a case where a cylindrical lens is measured as the test object W will be described with reference to FIG.

  Fig.7 (a) is a figure which shows the method of measuring the shape of the circumferential direction in the surface of a cylindrical lens. The direction in which the probe 4 tilts when the probe sphere 2 is brought into contact with the surface portion p of the cylindrical lens (the direction opposite to the direction in which the probe sphere 2 moves) is orthogonal to the top ridge line R of the cylindrical lens. Therefore, by performing the same process as the flowchart shown in FIG. 4, the control unit 14 sets the scanning path m1 of the probe 4 and acquires position information at a plurality of measurement points on the scanning path m1. Next, as shown in FIG. 7B, the control unit 14 sets a scanning path m2 that is parallel to the scanning path m1 and separated by a distance d, and position information is obtained at a plurality of measurement points on the scanning path m2. get. In this way, a plurality of scanning paths for scanning the probe 4 are set in parallel while sequentially shifting by the distance d, and position information is acquired at a plurality of measurement points in each scanning path. Thereby, the shape of the cylindrical lens can be measured three-dimensionally.

  FIG. 7C is a diagram illustrating a method of measuring the shape in the direction parallel to the top ridge line R on the surface of the cylindrical lens. The direction in which the probe 4 tilts when the probe sphere 2 is brought into contact with the surface portion p of the cylindrical lens (the direction opposite to the direction in which the probe sphere 2 moves) is orthogonal to the top ridge line R of the cylindrical lens. Therefore, the control unit 14 sets the probe scanning path m1 so that the scanning direction of the probe 4 is orthogonal to the direction in which the probe 4 is inclined, that is, the direction parallel to the top ridge line R. Position information is acquired at a plurality of measurement points on the scanning path m1. Next, as shown in FIG. 7D, the control unit 14 sets a scanning path m2 that is parallel to the scanning path m1 and that is separated by a distance d, and position information is obtained at a plurality of scanning locations on the scanning path m2. get. In this way, a plurality of scanning paths for scanning the probe 4 are set in parallel while sequentially shifting by the distance d, and position information is acquired at a plurality of measurement points in each scanning path. Thereby, the shape of the cylindrical lens can be measured three-dimensionally. Here, in the third embodiment, the interval between adjacent scanning paths is constant (for example, the distance d between the scanning path m1 and the scanning path m2), but is not limited thereto. For example, the interval between adjacent scanning paths may be arbitrarily set as necessary, such as narrowing the interval on a steep slope and increasing the interval on a gentle slope.

  In any of the above embodiments, the test surface has been described as a convex surface, but the test surface may be a concave surface. When the test surface is concave, the bottom of the test surface is located in the direction in which the probe ball moves when the tip of the probe is brought into contact with the test surface (the direction opposite to the direction in which the probe 4 is tilted). It will be.

  As mentioned above, although preferred embodiment of this invention was described, it cannot be overemphasized that this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

Claims (10)

A measurement method for measuring the shape of the test surface by causing the probe to scan relative to the test surface with the tip of the probe in contact with the test surface,
A contact step of bringing the tip of the probe into contact with the test surface;
Scanning when the probe is scanned relative to the test surface for a line including a path along which the tip moves on the test surface when the probe tip is brought into contact with the test surface A setting process to set as a route;
An acquisition step of scanning the probe along the scanning path and acquiring position information at a plurality of measurement points on the scanning path;
A determining step of determining a shape of the test surface based on the position information on the scanning path;
A measuring method characterized by comprising.   The said setting step detects the inclination of the probe when the tip of the probe is brought into contact with the test surface, and sets the scanning path based on the inclination of the probe. The measuring method as described in.   The setting step includes a first tilt amount that is an amount by which the probe is tilted in the first direction when the tip of the probe is brought into contact with the test surface, and a second direction in which the probe is different from the first direction. 3. The scan path is set based on the first tilt amount and the second tilt amount by detecting a second tilt amount that is tilted to the right. 4. Measuring method.   4. The measurement method according to claim 1, wherein, in the contact step, a tip of the probe is brought into contact with a portion having an inclination on the test surface. 5.   5. The acquisition process according to claim 1, wherein the acquiring step relatively scans the probe a plurality of times along the scanning path to acquire position information on the scanning path. The measuring method as described in. The acquisition step includes scanning the probe relative to the test surface along a second scan path on the test surface parallel to the scan path, and a plurality of scans on the second scan path. Obtain location information at the measurement location,
The determining step determines the shape of the test surface based on position information acquired on the scanning path and position information acquired on the second scanning path.
The measurement method according to any one of claims 1 to 5, wherein:   The measurement according to claim 6, wherein in the obtaining step, the probe is relatively scanned a plurality of times along the second scanning path, and position information on the second scanning path is obtained. Method.   A correction step of determining an angle at which the probe is tilted at each measurement location based on the first tilt amount and the second tilt amount, and correcting the position information measured at the measurement location based on the angle. The measurement method according to claim 3, further comprising: In a measurement apparatus that measures the shape of the test surface by causing the probe to scan relative to the test surface in a state where the tip of the probe is in contact with the test surface, the probe is placed on the test surface. A determination method for determining a scanning path when relatively scanning is performed,
A contact step of bringing the tip of the probe into contact with the test surface;
When the tip of the probe is brought into contact with the test surface, a line on the test surface including a path along which the tip has moved on the test surface is indicated relative to the test surface. A determination step for determining as a scanning path when scanning is performed;
A determination method characterized by comprising: A measuring device that measures the shape of the test surface by causing the probe to scan relative to the test surface with the tip of the probe in contact with the test surface,
A control unit for controlling the movement of the probe and controlling the measurement of the shape of the test surface;
The controller is
Bringing the tip of the probe into contact with the test surface;
Scanning when the probe is scanned relative to the test surface for a line including a path along which the tip moves on the test surface when the probe tip is brought into contact with the test surface Set as a route,
Scanning the probe along the scanning path, obtaining position information at a plurality of measurement points on the scanning path;
Determining the shape of the test surface based on the position information on the scanning path;
A measuring device.

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