JP2005127810A - Three-dimensional coordinate measuring method and device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a measuring and analysis method for determining accurately the relative position relation among each surface, relative to a plurality of surfaces, especially a plurality of free curved surfaces. <P>SOLUTION: A holding member is allowed to make one revolution and the peripheral part of the holding member is measured by a measuring probe prior to measurement of an inspection object, and information on the rotation shaft of a rotation mechanism is calculated from the measurement result. A rotation angle when measuring the face shape of the first face is stored as the first rotation angle, to thereby acquire surface shape data of the first face, and a rotation angle when measuring the surface shape of the second face is stored as the second rotation angle, to thereby acquire face shape data of the second face. Then, the relative position relation between the first face and the second face is calculated from information on the rotation shaft of the rotation mechanism, the face shape data of the first face, the face shape data of the second face, the first rotation angle and the second rotation angle. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a three-dimensional coordinate measurement method, and more particularly to a three-dimensional coordinate measurement method for obtaining a relative positional relationship between a plurality of surfaces constituting an optical element. Moreover, it is related with an apparatus provided with the three-dimensional coordinate measuring method.

Examples of the optical element include a lens and a prism. The evaluation items of this optical element include the surface shape and the relative positional relationship (eccentricity) of the surface. In order to perform these evaluations, it is necessary to measure the surface shape of the optical element and calculate the relative position of each surface. Therefore, the establishment of a measurement method is an important issue in terms of quality control in the optical element manufacturing process. In particular, when the optical element has a free-form surface, it is necessary to accurately determine the shape of the free-form surface and the relative positional relationship between a plurality of surfaces. In an optical element having a free-form surface, an apparatus for measuring the surface shape is provided. , Patent Document 1, Patent Document 2, and Patent Document 3.
JP-A-9-146002 JP 2002-250621 A JP 2002-250622 A

  However, what is disclosed in Patent Literature 1 and Patent Literature 3 is a technique for accurately measuring the surface shape. Patent Document 2 discloses a technique for obtaining a positional relationship between optical elements. Therefore, these patent documents do not disclose a technique for accurately obtaining the relative positional relationship between the surfaces.

  The present technology has been made in view of such a state of the prior art, and provides a measurement / analysis method for accurately obtaining the relative positional relationship of each surface of a plurality of surfaces, particularly a plurality of free-form surfaces. That is.

  In the three-dimensional coordinate measuring method of the present invention, a test object having at least two surfaces is held by a holding member connected to a rotation mechanism, and the holding member is rotated prior to measurement of the test object. Measure the outer periphery of the holding member with a measurement probe, calculate information about the rotation axis of the holding member from the measurement result, and rotate the holding member so that the first surface of the test object faces the measurement probe The rotation angle is stored as a first rotation angle, the surface shape of the first surface of the test object is measured, surface shape data of the first surface is obtained, and the second surface of the test object is obtained. The holding member is rotated so as to face the measurement probe, the rotation angle is stored as a second rotation angle, the surface shape of the second surface of the test object is measured, and the surface of the second surface is measured. Obtain shape data, information about the rotation axis, surface shape of the first surface Over data, the second surface shape data, the first rotation angle, from the second rotation angle, and calculates the relative positional relationship of the said first surface a second surface.

  The three-dimensional coordinate measurement method of the present invention is characterized in that the information about the rotation axis is based on a measurement result at the first position of the measurement probe and a distance from the central axis to the outer peripheral surface of the holding member.

  In the three-dimensional coordinate measurement method of the present invention, the holding member has a cylindrical shape, and the distance is a radius of the cylinder.

  The three-dimensional coordinate measurement method of the present invention is characterized in that the information about the rotation axis is based on measurement at a first position of the measurement probe and measurement at a second position of the measurement probe.

  The three-dimensional coordinate measuring apparatus of the present invention is provided with a probe for measuring the shape of a test object having at least two surfaces, a holding member for holding the test object, a rotating mechanism for rotating the holding member, and the rotating mechanism, A detection element for detecting a rotation angle, the probe, and a processing device for performing processing based on information from the detection element, the processing device rotating the holding member prior to measurement of the test object. Measuring the outer periphery of the holding member, calculating information on the rotation axis of the holding member from the measurement results, measuring a plurality of surfaces of the test object, the surface shape of the first surface, and the second surface A process of acquiring surface shape data, a process of acquiring information from the detection element at the time of measuring the first surface, a process of acquiring information from the detection element at the time of measuring the second surface, information on the rotation axis, First side Beauty second surface shape data, based on information from the Symbol detection element, characterized in that it comprises the step of calculating the relative positional relationship between the first surface and the second surface.

  According to the three-dimensional coordinate measurement method of the present invention, it is possible to accurately obtain the relative position of each test surface with respect to a plurality of test surfaces. For this reason, in the evaluation of optical elements and the like, the relative eccentricity and shape error on a plurality of test surfaces can be understood, so that it can be reflected in elucidation of the cause of optical performance deterioration, correction in manufacturing, etc. . In addition, a three-dimensional measuring apparatus having such effects can be realized.

  Hereinafter, the three-dimensional coordinate measuring method and apparatus of the present invention will be described. Here, the prism is the test object. Since the prism is composed of a plurality of surfaces, the relative positional relationship between the surfaces is obtained. Examples of surfaces include free-form surfaces, cylindrical surfaces, anamorphic surfaces, aspheric surfaces, spherical surfaces, and planes.

  The free-form surface has various definition expressions as expression methods, and an example is defined by the following expression. The Z axis of this defining formula is the axis of the free-form surface.

∞
Z = cr ² / [1 + √ {1− (1 + k) c ² r ² }] + ΣC _j X ^m Y ⁿ
j = 2
... (a)
Here, the first term of the equation (a) is a spherical term, and the second term is a free-form surface term.

In the spherical term,
c: curvature of vertex k: conic constant (conical constant)
r = √ (X ² + Y ² )
It is.

The free-form surface term is
66
ΣC _j X ^m Y ⁿ
j = 2
= C ₂ X + C ₃ Y
+ C ₄ X ² + C ₅ XY + C ₆ Y ²
+ C ₇ X ³ + C ₈ X ² Y + C ₉ XY ² + C ¹⁰ Y 3
+ C ₁₁ X ⁴ + C ₁₂ X ³ Y + C ₁₃ X ² Y ² + C ₁₄ XY ³ + C ₁₅ Y ⁴
+ C ₁₆ X ⁵ + C ₁₇ X ⁴ Y + C ₁₈ X ³ Y ² + C ₁₉ X ² Y ³ + C ₂₀ XY ⁴
+ C ₂₁ Y ⁵
+ C ₂₂ X ⁶ + C ₂₃ X ⁵ Y + C ₂₄ X ⁴ Y ² + C ₂₅ X ³ Y ³ + C ₂₆ X ² Y ⁴
+ C ₂₇ XY ⁵ + C ₂₈ Y ⁶
+ C ₂₉ X ⁷ + C ₃₀ X ⁶ Y + C ₃₁ X ⁵ Y ² + C ₃₂ X ⁴ Y ³ + C ₃₃ X ³ Y ⁴
+ C ₃₄ X ² Y ⁵ + C ₃₅ XY ⁶ + C ₃₆ Y ⁷
・ ・ ・ ・ ・ ・
However, C _j (j is an integer of 2 or more) is a coefficient. In general, the free-form surface formula does not have a symmetric plane on both the XZ plane and the YZ plane, but there is only one symmetric plane parallel to the YZ plane by setting all odd-order terms of X to 0. It becomes a free-form surface. Also, by setting all odd-numbered terms of Y to 0, a free-form surface having only one symmetry plane parallel to the XZ plane is obtained.

  Here, it is assumed that the prism is composed of a free-form surface. In order to measure each surface of such a prism, the prism is held by a cylindrical holding member. Then, the holding member is rotated by the rotation mechanism. If it does in this way, the surface to measure can be made to face a probe one by one by rotating a holding member. Since each surface is measured with the same probe, there is no difference in the measurement coordinate system of each surface. Therefore, the positional relationship of each surface can be easily obtained from the measurement data of each surface and the position (angle) at which the rotary stage was fixed at the time of measuring each surface. However, this is a case where the central axis of the holding member and the rotation axis of the rotation mechanism coincide.

  However, when the central axis of the holding member does not coincide with the rotation axis of the rotation mechanism, the holding member is shaken by the rotation. That is, the direction of the central axis of the holding member with respect to the rotation axis of the rotation mechanism differs for each rotation angle. Then, since blur information is added to each surface, the positional relationship between the surfaces cannot be obtained as it is. The shake is a shake of the central axis of the holding member with respect to the rotation axis of the rotation mechanism.

Then, the holding member is made into a cylinder, this holding member is rotated, and the outer peripheral surface is measured with a probe. In this way, the shake of the central axis of the holding member can be derived from the measurement result of the holding member. At this time, if the initial position is determined, the rotation angle at an arbitrary position can be known with the initial position as a reference. If it does so, the blur information in the rotation angle will be obtained. Information on the rotation axis of the rotation mechanism can be acquired from the information on the shake. Also, a probe for measuring each surface of the prism is used as a probe for measuring the outer peripheral surface of the holding member. Therefore, the coordinate system when measuring the outer peripheral surface of the holding member is the same as the coordinate system when measuring each surface of the prism. Therefore, when each surface of the prism is measured, even if the influence of the fluctuation of the central axis of the holding member is added to the data of the surface, the influence can be corrected. As a result, the positional relationship between the surfaces can be obtained.

  A first embodiment of the three-dimensional coordinate measuring method and apparatus will be described. FIG. 1 is a diagram illustrating a measuring unit of the three-dimensional coordinate measuring apparatus. In this embodiment, the test object is a prism. This prism has surfaces S1 to S3 as optical surfaces. In this embodiment, the relative positions of these three surfaces are calculated.

  In FIG. 1, reference numeral 1 denotes a rotating stage as a rotating mechanism, 2 denotes a reference cylinder as a holding member, 3 denotes a rotating shaft of the rotating stage 1, and 4 denotes a stylus probe (hereinafter simply referred to as a probe 4). . Reference numeral 7 denotes a fixture, which fixes the prism 6 to the reference cylinder 2. Here, the reference cylinder 2 is installed so that the central axis (rotation symmetry axis) substantially coincides with the rotation axis 3 of the rotary stage 1. The reference cylinder 2 has a very high roundness. The rotary stage 1 has a structure that can be stopped at a desired angle. Furthermore, the rotary stage 1 has a built-in detection element (not shown). With this detection element, the position (angle) when the rotary stage 1 is stopped can be detected with high accuracy. Therefore, if the initial position is set appropriately, the rotation angle from the initial position to the stop position can be calculated.

  In the text, the direction along the rotation axis 3 is defined as the X-axis direction, and the direction in which the probe 4 is displaced is defined as the Z-axis direction (the vertical direction in this embodiment). The Y-axis direction is a direction orthogonal to both the X-axis direction and the Z-axis direction. However, the coordinate system used for the analysis is not limited to this, and the same analysis can be performed using another coordinate system.

Prior to measuring the shapes of the surfaces S _{1 to} S ₃ , the outer peripheral surface of the reference cylinder 2 is measured. The probe 4 is used for this measurement. If in this way, a measurement coordinate system of the reference cylinder 2, measurement coordinate system of the surface S ₁ to S ₃ are the same.

  The probe 4 is positioned on the outer peripheral surface of the reference cylinder 2. At this time, the probe 4 is moved in the Y direction to find a position where the position in the Z direction is the highest. In FIG. 1, the point P is the highest position, and this is the initial position. When the rotary stage 1 is rotated with the probe 4 in contact with the point P, the reference cylinder 2 also rotates. Here, if the rotation axis 3 of the rotary stage 1 and the two central axes 5 of the reference cylinder coincide with each other, the probe 4 does not move in the Z direction. That is, the output signal from the probe 4 is constant.

  However, in actuality, a slight deviation occurs between the rotation axis 3 of the rotary stage 1 and the central axis of the reference cylinder 2 due to an assembly error or the like. That is, as shown in FIG. 2, the center axis 5 of the reference cylinder 2 is shifted by ΔY in the Y-axis direction and ΔZ in the Z-axis direction with respect to the rotation axis 3 of the rotary stage 1. Here, in this embodiment, it is assumed that the center axis 5 of the reference cylinder 2 is displaced in parallel with the rotation axis 3 of the rotary stage 1.

  At point P, displacement occurs as the rotary stage 1 rotates. As shown in FIG. 2, the displacement is a sinusoidal displacement H with respect to the rotation angle of the rotary stage 1 when the amount of axial deviation is (ΔY, ΔZ). Here, when the amount of axial deviation is small, the displacement H accompanying the rotation at the point P can be expressed by the following equation (1).

(1)
θ: Rotation stage rotation angle R: Cylinder radius FIG. 3 shows a displacement H at Y = 0 accompanying rotation. Here, the radius of the reference cylinder 2 is 5 mm. Further, it is assumed that the center axis 5 of the reference cylinder 2 is shifted from the rotation axis by ΔY = 0.02 mm and ΔZ = 0.03 mm (θ = 0 °).

  Therefore, by obtaining the PV value and the rotation angle (phase) at which the peak is obtained from the measurement result of the outer peripheral surface of the reference cylinder 2, the amount of axis deviation (ΔY, ΔZ) can be obtained. On the other hand, the radius of the reference cylinder 2 is calculated with high accuracy. The position of the point where the YZ cross section at the point P and the rotation axis 3 of the rotary stage 1 intersect can be obtained from the amount of axis deviation (ΔY, ΔZ) and the radius of the reference cylinder 2.

Then, a shape measurement of each surface S ₁ to S _3. When measuring each surface, each surface is positioned with respect to the probe 4 so that measurement can be performed with the highest accuracy. This positioning is performed by rotating the rotary stage 1. In the case of this embodiment, the probe 4 detects displacement in the Z-axis direction (vertical direction). Therefore, when each surface becomes substantially horizontal with the XY plane, the rotation of the rotary stage 1 is stopped and fixed there.

4A to 4C show how the shapes of the surfaces S _{1 to} S ₃ are measured. The area indicated by M ₁ ~M ₃ on each side refers to a region that was measured shape probe 4. Further, it is desirable that the measured region is a region including the effective range of each surface. The effective range is an area through which light rays contributing to the formation of a good image pass.

4A to 4C, the Z-axis at the time of measurement of the surfaces S _{1 to} S ₃ is Z _{1 to} Z ₃ , and the Y-axis is Y ₁ to Y ₃ . Further, the Z axis at the initial position of the rotary stage 1 (for example, a rotation angle of 0 degree) is set as Z ₀ . The angles between Z _{1 to} Z ₃ and Z ₀ are defined as θ _{1 to} θ ₃ , respectively. These θ _{1 to} θ ₃ correspond to the rotation angle of the rotary stage 1. This rotation angle is based on the initial position.

First, in order to measure the surface S _1, it rotates the rotary stage 1. As shown in FIG. 4 (a), where the surface S ₁ is becomes X-Y plane and substantially horizontal, stopping the rotation of the rotary stage 1. Then, the rotation angle θ ₁ at this position is detected and recorded with high accuracy. In this position, the surface S ₁ faces the probe 4. Therefore, the probe 4 is brought into contact with the surface S ₁ and measurement is started.

When the measurement of the surface S ₁ is completed, the probe 4 is moved away from the surface S ₁ and moved to the standby position. Then, by rotating the rotary stage 1, as shown in FIG. 4 (b), where the surface S ₂ becomes X-Y plane and substantially horizontal, stopping the rotation of the rotary stage 1. Then, the rotation angle θ ₂ at this position is detected and recorded with high accuracy. Then, the measurement surface S _2. The same applies to the surface S _3.

When the measurement is completed, the shape data of each surface S ₁ to S _3, the respective surfaces S ₁ to S a rotational angle theta ₁ through? ₃ during measurement of ₃ is obtained as the measurement result. Therefore, the relative positions of the surfaces S _{1 to} S ₃ are calculated from these measurement results.

Therefore, the position of the rotary shaft 3 of the rotary stage 1 is calculated for each surface. At this time, the position of the central axis 5 of the reference cylinder 2 is different for each surface. Here, how much the center axis 5 of the reference cylinder 2 when each surface is measured is relative to the rotation axis 3 of the rotary stage 1 is determined by the amount of axial deviation (ΔY on each surface S _{1 to} S _3. , ΔZ). Therefore, the center axis 5 of the reference cylinder 2 in each measurement is made to coincide with the rotation axis 3 of the rotary stage 1 based on the amount of axis deviation (ΔY, ΔZ).

Subsequently, rotation coordinate transformation is performed around the central axis 5 of the reference cylinder 2. As described above, the surfaces S _{1 to} S ₃ face the probe 4 during measurement. Therefore, the normal direction of the surface at the time of measurement is the Z-axis direction. However, as can be seen from the outer diameter shape, the normal direction of each surface is different. Therefore, rotation coordinate conversion is performed so that the normal direction of each surface is correct.

Here, the plane S ₁ is used as a reference. In measuring the surface S ₁ , the rotary stage 1 is rotated by θ ₁ . On the other hand, in measuring the surface S ₂ , the rotary stage 1 is rotated by θ ₂ . Therefore, when shifting from the measurement of the surface _{1 to} the measurement of the surface S ₂ , the stage 1 is rotated by (θ ₁ −θ ₂ ). Therefore, rotation coordinate conversion is performed around the X axis by the amount (θ ₁ −θ ₂ ) with respect to the measurement coordinates of the surface S ₂ . Similarly, rotation coordinate conversion is performed around the X axis by the amount (θ ₁ −θ ₃ ) with respect to the measurement coordinates of the surface S ₂ .

In the above example, the center axis 5 of the reference cylinder 2 calculated at the time of measuring each surface is aligned with the rotation axis 3 of the rotary stage 1. However, for example, when the deviation between the rotation axis 3 of the rotary stage 1 and the center axis 5 of the reference cylinder 2 is small, the axis may be aligned with the center axis 5 of any one of the reference cylinders 2. Even in such a case, the center axis 5 of the reference cylinder 2 is calculated together with the shape measurement of the surfaces S _{1 to} S ₃ .

As described above, there is a deviation in the central axis 5 of the reference cylinder 2, and the position (angle) of the rotary stage to be fixed is different every time the shape of each surface is measured. Therefore, the amount of deviation (ΔY, ΔZ) is This is different for each surface S _{1 to} S ₃ . Therefore, processing for spatially matching the central axis 5 of the reference cylinder 2 is performed. Here, the center axis 5 of the reference cylinder 2 when the surface S ₁ is measured is aligned with the center axis when the remaining surfaces S ₂ and S ₃ are measured. For example, the displacement when the surface S ₁ is measured is (ΔY ₁ , ΔZ ₁ ), the displacement when the surface S ₂ is measured (ΔY ₂ , ΔZ ₂ ), and the displacement when the surface S ₃ is measured is (ΔY ₃ and ΔZ ₃ ).

In this case, the deviation between the surface S ₁ and the surface S ₂ is | ΔY ₁ −ΔY ₂ | in the Y-axis direction and | ΔZ ₁ −ΔZ ₂ | in the Z-axis direction. Therefore, | ΔY ₁ −ΔY ₂ | and | ΔZ ₁ −ΔZ ₂ | are added to or subtracted from the shape measurement data of the surface S ₂ as correction amounts. Further, the deviation between the surface S ₁ and the surface S ₃ is | ΔY ₁ −ΔY ₃ | in the Y-axis direction and | ΔZ ₁ −ΔZ ₃ | in the Z-axis direction. Therefore, the correction is performed in the same manner.

In the above description, the surface S ₁ is used as a reference, but the initial position Z ₀ of the rotary stage 1 may be used as a reference. In this case, the surface S ₁ theta _1, on the surface S ₂ theta _2, the surface S ₃ in amounts of theta _3, it will implement the coordinate transformation of the rotation.

FIG. 5 shows a result of rotating coordinate conversion for each surface to be examined with reference to the Z axis Z ₀ at the reference position of the rotary stage 1. Thereby, it becomes possible to reconstruct the shape measurement result of each test surface according to the actual shape, and it is possible to obtain information on the eccentricity of the surface.

  For reference, a method of expressing shape measurement data with design coordinates is shown. The shape measurement data of each surface is point sequence data of positions sampled by scanning along the shape of the surface. Therefore, it is possible to obtain the position of the design coordinate system based on this measurement result.

In order to calculate the design coordinate system of each surface, the design shape and the measurement result are overlapped for each surface. Then, coordinate conversion is performed so that the residual at that time is minimized, and the parameters (shift, tilt) at that time may be optimized. This analysis uses an optimization method such as Newton's method. For example, for the measurement point (x _i , y _i ) [i = 1... M (measurement point m)], the Z coordinate F (xi, yi) of the design shape function F and the actual measurement Z coordinate zi fixed point number m)
F (x, y): Design shape function As a result, it becomes possible to clarify the measurement result of the shape and the relative positions of the rotation axis and the design coordinate system.

Further, when the position of the design coordinate system is calculated, the difference between the measurement result and the design shape becomes the shape error component. Therefore, the shape error component can be approximated by a function by fitting the shape error component with a polynomial, for example. As a result of these analyses, it is possible to calculate the position of the design coordinate system from the measurement results of each surface, and to approximate the shape by the following function G (x, y) using the coordinate system.

G (x, y): Function approximating measurement results
F (x, y): Design shape function
E (x, y): Function approximating shape error component These analyzes are performed in advance. Similarly to the above analysis, rotation coordinate conversion is performed around the rotation axis 3 of the rotary stage 1 by the angle recorded at the time of measuring each surface. In this way, as shown in FIG. 6, it is possible to calculate the relative positions of the design coordinate systems D _{1 to} D _{3 of each surface} and the approximate shapes G _{1 to} G ₃ expressed by functions.

  Thus, by approximating the shape of each surface with a function, the amount of eccentricity and the shape error can be obtained quantitatively. Furthermore, since the optical performance can be easily simulated by using the shape error approximated by the amount of eccentricity and the function, the optical performance can be predicted from the measurement result.

  The method for calculating the design coordinate system is not limited to the above method. For example, as shown in FIG. 7, a method may be used in which the mark m or the like is processed on the surface of the specimen and is derived from the measurement result. In this case, it is necessary to clarify in advance the position of the mark m used for measurement and the relative position of the design coordinate system D.

In this embodiment, the center axis 5 of the reference cylinder 2 is inclined with respect to the rotation axis of the rotary stage 1. In this case, the probe is moved to a point Q (position) other than the point P as shown in FIG. Therefore, in the present embodiment, as shown in FIG. 9, the deviation amount (ΔY _P , ΔZ _P ) at the point _P and the deviation amount (ΔY _Q , ΔZ _Q ) at the point Q are calculated.

Accordingly, a straight line connecting points where the YZ cross section and the rotation axis at each point intersect becomes the rotation axis 3 of the rotary stage 1. A straight line connecting the deviation amounts (ΔY _P , ΔZ _P ) and the deviation amounts (ΔY _Q , ΔZ _Q ) of each point becomes the central axis 5 of the reference cylinder 2. Therefore, the position (including the inclination) of the central axis 5 of the reference cylinder 2 can be calculated from these deviation amounts.

  In addition, you may implement the position to measure at two or more points. In this way, the position of the rotating shaft 3 can be obtained with higher accuracy.

  If the position of the central axis 5 of the reference cylinder 2 is obtained, the measurement can be performed in the same manner as in the first embodiment.

  In addition, when the shape of the surface is a plane, the direction of the normal vector of each surface can be calculated. Therefore, it is possible to calculate an angle formed by each test surface and a pyramid error.

  Further, this measurement is not limited to the prism, and may be a lens, for example. FIG. 10 shows a state when a lens is measured as a test object. In this case, the rotary stage is rotated approximately 180 degrees and the shape is measured for each surface. And it becomes possible to measure simultaneously the shape and eccentricity of each surface by taking the same analysis method. As a result, since the relative position of the shape is known, the lens thickness can be calculated in the same manner.

  Note that the measuring instrument used for this measurement is not limited to a stylus type probe, and any method may be used as long as the measurement is possible, for example, an optical probe method may be used. In the case of an optical probe, measurement can be performed in a non-contact manner on the test surface, and therefore, measurement can be performed on the test surface in a nondestructive manner. Further, the action of the test surface may be a refracting surface, a reflecting surface, or a coated surface as long as measurement is possible.

  Further, the holding member is not limited to the reference cylinder 2. That is, the outer shape is not limited as long as the outer peripheral surface of the holding member can be measured with a probe. For example, it may be a quadrangular column or a polygonal column. However, if it is a cylinder, since the measurement of an outer peripheral surface can be performed smoothly, it is more preferable.

It is a figure which shows a mode that the center axis | shaft of a reference | standard cylinder is calculated | required. It is a figure which shows the mode of the shift | offset | difference of the center axis | shaft of a reference | standard cylinder with respect to the rotating shaft of a rotation stage. It is a figure which shows the signal output from a probe in the process of calculating | requiring the center axis | shaft of a reference | standard cylinder. It is a state of measuring each test surface of the specimen, (a) measuring the surface S ₁ , (b) measuring the surface S ₂ , (c) the surface S 1 ₃ is a diagram showing a state of measuring. It is a figure which shows a mode that each surface was rotated around the rotating shaft of the rotation stage. It is a figure which shows a mode that the design coordinate system of each surface is rotated around the rotating shaft of a rotation stage. It is a figure which shows the example provided in the external shape of the processed mark and to-be-tested object in order to calculate a design coordinate system. It is a figure which shows another mode which calculates | requires the center axis | shaft of a reference | standard cylinder. It is a figure which shows the mode of the shift | offset | difference of the center axis | shaft of a reference | standard cylinder with respect to the rotating shaft of a rotation stage. It is a figure which shows a mode that the amount of eccentricity of the surface of the lens which is a test object is measured.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rotation stage 2 Reference cylinder 3 Rotation axis 4 Stylus probe 5 Reference cylinder axis (axis of rotational symmetry)
6 Test object (prism)
7 Fixing tool 8 Test object (lens)
S1, S2, S3 Test surface
Z1, Z2, Z3 Z coordinate axes when measuring the shape of each surface
Z1, Z2, Z3 Y coordinate axis when measuring the shape of each surface
Z0 Z axis at the reference position of rotary stage θ1, θ2, θ3 Angles between Z axis (Z1-3) and Z0 when measuring the shape of each surface ΔX, ΔY Axis deviation of the reference cylinder relative to the rotary axis
M1, M2, M3 shape measurement area of each surface
D1, D2, D3, D design coordinate system of each surface
G1, G2, G3 Shape approximated by function based on measurement results on each surface
m Marks processed for design coordinate system calculation

Claims (5)

A test object having at least two surfaces is held by a holding member connected to a rotation mechanism,
Prior to measurement of the test object, the holding member is rotated and the outer periphery of the holding member is measured with a measuring probe,
From the measurement result, information on the rotation axis of the rotation mechanism is calculated,
Rotating the holding member so that the first surface of the test object faces the measurement probe, and storing the rotation angle as a first rotation angle;
Measuring the surface shape of the first surface of the test object to obtain surface shape data of the first surface;
Rotating the holding member so that the second surface of the test object faces the measurement probe, and storing the rotation angle as a second rotation angle;
Measuring the surface shape of the second surface of the test object to obtain surface shape data of the second surface;
From the information on the rotation axis of the rotation mechanism, the surface shape data of the first surface, the second surface shape data, the first rotation angle, and the second rotation angle, the first surface and the second surface A three-dimensional coordinate measurement method characterized by calculating a relative positional relationship between 2. The three-dimensional coordinate measurement according to claim 1, wherein the information about the rotation axis of the rotation mechanism is based on a measurement result at the first position of the measurement probe and a distance from the central axis to the outer peripheral surface of the holding member. Method. The three-dimensional coordinate measuring method according to claim 2, wherein the holding member has a cylindrical shape, and the distance is a radius of the cylinder. 2. The three-dimensional coordinate measurement method according to claim 1, wherein the information about the rotation axis is based on measurement at a first position of the measurement probe and measurement at a second position of the measurement probe. A probe for measuring the shape of an object having at least two surfaces;
A holding member for holding the object to be rotated; a rotating mechanism for rotating the holding member;
A detection element provided in the rotation mechanism for detecting a rotation angle;
A processing device for performing processing based on information from the probe and the detection element;
The processor is
Prior to the measurement of the test object, the holding member is rotated to measure the outer peripheral portion of the holding member, and the information about the rotation axis of the rotation mechanism is calculated from the measurement result.
Measuring a plurality of surfaces of the specimen;
A process of acquiring surface shape data of the first surface and surface shape data of the second surface;
Obtaining information from the detection element at the time of measuring the first surface and information from the detection element at the time of measuring the second surface;
A relative positional relationship between the first surface and the second surface is calculated based on information on the rotation axis of the rotation mechanism, the first surface and second surface shape data, and information from the detection element. A three-dimensional coordinate measuring apparatus comprising a process.

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