KR101138149B1 - Three-dimensional shape measuring method - Google Patents

Abstract

The high inclination part of a measurement object, such as a lens, is measured with high precision. The lens 11 is placed in a first installation state inclined around the Y axis of the measuring device 1 (S3-1). The lens 11 is rotated 90 degrees about the Z axis of the design coordinate system from the first installation state to be the second installation state (S3-8). For each of the first and second mounting states, the first measurement data group is obtained by measuring the surface XYZ axis coordinates on a straight line in the X axis direction passing through the design vertex coordinates of the lens 11, The second measurement data group is obtained by measuring the surface XYZ axis coordinates on a straight line in the Y axis direction passing through the design vertex coordinates of the lens 11 (S3-4, S3-11). The difference with a design shape is computed about each of a 1st and 2nd installation state using a 1st and 2nd measurement data group. The difference with the calculated design shape is synthesize | combined (S3-15).

Description

Three-dimensional shape measurement method {THREE-DIMENSIONAL SHAPE MEASURING METHOD}

Industrial Applicability The present invention relates to three-dimensional shape evaluation of a lens in which the inclination to the optical axis of the lens surface is high inclination, such as a lens used in a mobile phone with a camera, a pickup lens used in an optical disk storage device such as a blue-ray disc (BD), and the like. It relates to a suitable three-dimensional shape measurement method.

As a method of measuring and evaluating a conventional lens shape, there is a method of measuring a high inclined plane by a probe formed of a micro air slider (see Patent Document 1, for example). FIG. 26 shows a conventional three-dimensional shape measuring method described in Patent Document 1. As shown in FIG.

 In FIG. 26, the probe unit 100 includes a probe 102 having a stylus 101 at a lower end thereof. The micro air slider 103 on the upper side of the probe 102 is supported in a non-contact manner by an air bearing. The laser light Fr of the semiconductor laser 104 is guided to the mirror 105 provided on the top of the stylus 7. An atomic force operating between the stylus 101 and the workpiece 106 is reflected by the mirror 105 and an error signal according to the strength of the amount of light of the laser light Fr that has passed through the pinhole 107. By the error signal generating unit 108 for generating a, it is converted into a force in the vertical direction of the probe unit 100. The position of the entire probe unit 100 is feedback-controlled by the servo circuit 109 and the linear motor 110 based on the output from the error signal generator 108. The Z coordinate of the probe 102 is measured by the laser light Fz from the He-Ne laser (not shown) reflected by the mirror 105. Although it is possible to measure the high inclined plane with high accuracy by this method, the measurement of the inclined plane of 75 degrees is a limit even in the improved present.

However, in applications such as lenses used in mobile phones with cameras and pickup lenses used in optical disk storage devices such as blue-ray discs (BDs), for the purpose of improving the resolution and reducing the diameter of the condensed beam, It is necessary to have a lens whose inclination angle of the inclined surface exceeds 80 degrees, and further evaluation to a high inclined surface is required.

Therefore, the lens is tilted in three directions, measured in each installation direction, and two pieces of data in which the measurement areas overlap in the three-direction measurement data are synthesized to coincide in the XZ plane, and the synthesized data and the design shape are obtained. Some differences were evaluated (for example, refer patent document 2 and nonpatent literature 1).

FIG. 27 shows a measurement evaluation method for a conventional lens described in Patent Document 2. As shown in FIG. First, the lens is tilted in three directions and measured in each installation direction. Next, the obtained measurement data 200a, 200b, 200c are synthesized by adjusting the rotational position and the left and right positions so that the portions where the measurement regions overlap with each other coincide in the XZ plane. Then, the difference between the data 200d after the synthesis and the design shape is evaluated.

In addition, as a method of measuring and evaluating conventional lens characteristics, the lens is inclined in three directions, measured in each installation direction, one of these three directions is defined as reference data, and the other two directions with respect to the reference data. The data in which the measurement areas overlap in the measurement data of was synthesized so as to coincide in the XZ plane, and the difference between the synthesized data and the design shape was evaluated (see Patent Document 3, for example).

FIG. 28 shows a measurement evaluation method for a conventional lens described in Patent Document 3. As shown in FIG. First, the lens (mold) is installed horizontally, and the center portion 301a is measured. After that, the lens is tilted (the design optical axis 302 is inclined around the Y axis) to measure the portion 301b where the tilt of the lens surface with respect to the measuring device is reduced. In addition, the lens is rotated 180 degrees about the design optical axis 302, and the portion 301c on the opposite side on the same axis on which the lens is measured obliquely is measured. Then, the measurement data of the 301b and 301c parts are rotated and moved in parallel so that the measurement data coincides at the portions where the measurement areas of the 301b and 301c parts and the central part 301a overlap with respect to the center part 301a. In other words, data measured in three directions is synthesized based on the central portion 301a. And the shape is evaluated by the data after synthesis | combination.

(Patent Document 1)

Japanese Patent Laid-Open No. 6-265340

(Patent Document 2)

Japanese Laid-Open Patent Publication No. 2005-201656

(Patent Document 3)

International Publication No. 06/082368 Pamphlet

(Non-Patent Document 1)

Miura Katshiro, "Lens shape measurement system by laser probe method", O plus E, New Technology Communications, Inc., September, 2004, Vol. 46, No. 3, p1070-1074

However, in the conventional method, when the lens is shifted around an axis (X axis) different from the axis (Y axis) in which the lens is inclined, a shape error occurs. In other words, if the measurement of the Y cross section is not carried out in obtaining the measurement shape of the X cross section, and there is an installation deviation of the lens due to the rotational direction around the X axis, the measurement value includes an error. This point is demonstrated concretely below.

For example, as shown in FIG. 29, the inclination angle of the lens surface of the cross-sectional direction in the outermost part of effective diameter 1.6mm (radius R = 0.8mm) and R = 0.8mm is 75 degree from the lens vertex. Consider a case where an aspherical lens having a sag amount of 0.5 mm is measured. In FIG. 29, rotations are made around the X, Y, and Z axes as the A, B, and C axes, respectively.

The solid line 401a represents the lens cross section when there is no deviation due to rotation about the X axis (A axis). In addition, the dotted line 401b shows the lens cross section when it is installed inclining 1 degree with respect to the coordinate system of a measuring machine (axis A) about an X axis. When the measurement is started from the apex part of the lens, if the lens is inclined 1 ° from the A axis with respect to the coordinate system of the measuring instrument (dotted line 401b), at the position of X = -0.8mm, on the lens surface to which the stylus scans The position Y 'in the Y-axis direction is a position shifted from the sag amount h * sin (1 °) by 8.73 µm from the Y axis of the measuring instrument as shown by the following equation (1).

(Equation 1)

In addition, X in a Y 'position becomes a value shown by following formula (2).

(Equation 2)

Therefore, the error in the Z direction due to the inclination of the lens by 1 ° with respect to the coordinate system of the measuring instrument becomes a value represented by the following equation (3).

(Equation 3)

If the shape error of the lens due to this measurement error is not corrected, the beam cannot be made small in a lens such as a BD, and a problem such as an image blurring occurs in a lens for a mobile phone with a camera.

Further, in the conventional method, since the measurement data of the left and right parts are synthesized so as to overlap each other based on the measurement data of the center part, when the data are connected to each other with the measurement data, the order of the shape of the mm order is smaller than the order of µm or less. It is necessary to fit the data in the characteristic shape, and the synthesis is not easy. Moreover, in the conventional method, an error occurs in the correction calculation regarding the radius of the probe tip (probe R). In addition, the conventional method requires measurement by tilting the lens in three directions in order to obtain measurement data of one section.

This invention solves the said conventional subject and aims at providing the three-dimensional shape measuring method which can measure the high inclined part of measurement objects, such as a lens, with high precision.

The present invention provides a first installation state in which the measurement object is inclined around the Y-axis, and the measured object is a natural number of 2 or less of 90 degrees around the Z axis of the design coordinate system of the measurement object from the first installation state. In the X-axis direction passing through the vertex coordinates in the design of the measurement object for each of the first and second installation states by rotating one or more times in an angular increment of Measure the coordinates of the X-axis, Y-axis and Z-axis of the workpiece surface on a straight line to obtain a first measurement data group, and simultaneously measure the surface of the workpiece on a straight line in the Y-axis direction passing the vertex coordinates on the installation of the workpiece. Measure the coordinates of the X-axis, the Y-axis, and the Z-axis to obtain a second measurement data group, and use the first and second measurement data groups for each of the first and second installation states to design the design. Calculate the difference between W, and provides a three-dimensional shape measuring method for synthesis of a difference between the design shape on the first and second installation.

In the three-dimensional measuring method of the present invention, not only the first measurement data group which is the coordinates of the X-axis, Y-axis, and Z-axis of the surface of the base workpiece on the straight line in the X-axis direction, but also the X of the surface of the base-object on the straight line in the Y-axis direction The difference with a design shape is computed using the 2nd measurement data group which is the coordinate of an axis, a Y axis, and a Z axis. Therefore, even if there is a deviation in the mounting position of the workpiece around the X axis, the X, Y, and Z axis coordinates of the measurement data group can be calculated correctly, and the cross-sectional shape of the workpiece including the high inclined plane and the design shape The difference can be measured with high precision. In addition, since the surface of a workpiece is measured with respect to the 1st mounting state and the 2nd mounting state rotated about the Z axis of the design coordinate system of a workpiece from this 1st installation state, the whole surface of one measuring object including a high inclined surface is measured. The difference from the design shape can be obtained.

For example, the angle increment is 180 degrees, and the second installation state is one. In this case, the difference with a design shape can be measured with high precision with respect to the cross section on the X axis of the design coordinate system of a workpiece.

The angle increment may be 90 degrees, and the second installation state may be three. In this case, the difference with a design shape can be measured with high precision about the cross section of the X-axis and Y-axis of the design coordinate system of a workpiece.

Specifically, the calculation of the difference from the design shape using the first and second measurement data groups includes the rotation and translation of the first and second measurement data groups according to the inclination around the Y axis. Move and perform a preliminary coordinate transformation to coordinate transform the design coordinate system of the workpiece when there is no inclination around the Y axis, and design the first and second measurement data groups in which the preliminary coordinate transformation is performed. An alignment is performed to coordinate coordinates to fit the shape, and the difference between the first measurement data group in which the alignment is made and the design shape of the measurement object is calculated.

Or calculation of the difference with the said design shape using the said 1st and 2nd measurement data group rotates and translates the said 1st and 2nd measurement data group according to the inclination around the said Y axis, and the said Y axis A first alignment for performing a preliminary coordinate transformation for performing coordinate transformation on the design coordinate system of the measurement object when there is no inclination of the surroundings, and for fitting the first and second measurement data groups in which the preliminary coordinate transformation is performed to the design shape of the measurement object Amounts are calculated for the X-axis, Y-axis, Z-axis, A-axis and B-axis, and two or three of the first alignment amounts of the X-axis, Y-axis, Z-axis, A-axis and B-axis are fixed alignment amounts. Selects as, and performs the first coordinate transformation for coordinate transformation of the first measurement data group subjected to the preliminary coordinate transformation into the fixed alignment amount, and the first measurement data group for which the first coordinate transformation is performed. The first measurement in which the preliminary coordinate transformation is performed by calculating a second alignment amount matching the design shape of the measurement object with respect to an axis other than the fixed alignment amount among the X, Y, Z, A, and B axes. And performing a second alignment for transforming a data group into the fixed alignment amount and the second alignment amount, and calculating a difference between the first measurement data group in which the second alignment is made and the design shape of the measurement object.

In this case, when the scores of the measurement data groups are unevenly distributed with respect to the center of the design data, the cross-sectional shape of the measured object including the high inclined surface may be reduced even when the aspheric amount of the measured object is small or medium. It can measure with high precision.

The design shape for performing the said preliminary coordinate conversion may convert the design parameter according to the shape of an actual measured object. In this case, the preliminary coordinate transformation and subsequent processing can be performed with higher accuracy, and high precision measurement of the high inclined surface becomes possible.

Synthesis of the difference with the design shape for the first and second installation states may include manually adjusting the overlap of the difference with the design shape for the first and second installation states. Moreover, the synthesis | combination of the difference with the said design shape with respect to the said 1st and 2nd installation state is approximated by the least square method with respect to the difference with the said design shape with respect to the said 1st and 2nd installation state, respectively. A straight line may be obtained and coordinate transformation of the difference with the said design shape with respect to the said 1st and 2nd installation state may be included so that the said approximation straight line of a said 1st and 2nd installation state may overlap. By this processing, the difference between the cross-sectional shape and the design shape of the workpiece including the high inclined surface can be obtained with higher accuracy.

If planar measurement data is used instead of the second measurement data group, the three-dimensional shape of the measurement object can be measured.

As described above, in the three-dimensional shape measuring method of the present invention, the first installation state in which the measurement object is inclined and the second installation state rotated around the Z axis of the design coordinate system of the measurement object from the first installation state. , The first measurement data group that is the coordinates of the X, Y, and Z axes of the workpiece surface on the straight line in the X axis direction, as well as the coordinates of the X, Y, and Z axes of the workpiece surface on the straight line in the Y axis direction. The difference with a design shape is computed using 2 measurement data groups. Therefore, even if there is a deviation in the mounting position of the workpiece around the X axis, the X, Y, and Z axis coordinates of the measurement data group can be calculated correctly, and the shape and design of the entire cross section of the workpiece including the high inclined plane can be calculated. The difference from the shape can be measured with high accuracy.

Next, embodiment of this invention is described in detail with reference to an accompanying drawing. In the accompanying drawings, when it is necessary to distinguish between the fixed Cartesian coordinate axis and the design coordinate axis of the lens in the three-dimensional space set for the measuring device itself with respect to the coordinate axis, the former is attached with (UA3P) and the latter. "(Lens)" is attached to (者).

(First embodiment)

1 shows a three-dimensional shape measuring device (hereinafter, simply a measuring device) 1 capable of executing the three-dimensional shape measuring method of the present invention. The measuring device 1 includes an upper stone panel 5 mounted on a lower stone panel 2 via an X-axis stage 3 and a Y-axis stage 4 driven by a motor. The probe unit 100 (as described with reference to FIG. 26) is mounted on the upper stone panel 5 so as to be movable in the Z-axis direction. The laser light from the He-Ne laser 6 branches into the laser light Fx, Fy, Fz in the XYZ axis direction by the optical system 7. The laser beam Fx is irradiated to the X-axis mirror 8 fixed to the lower stone tablet 2, and X coordinate is measured. Similarly, laser light Fy is irradiated to the Y-axis mirror 9 fixed to the lower stone tablet 2, and Y coordinate is measured. The Z-axis laser light Fz is bifurcated into two, so that the Z-coordinate on the measurement surface is determined from the reflected light of the Z-axis mirror fixed to the upper part of the lower stone tablet plate 2 and the mirror 105 (see FIG. 26) on the top of the stylus 101. Is measured.

2, the jig | tool 12 for installation of the lens 11 (it is not limited to a lens but may be a metal mold | die for lens formation) which is a measurement object is A-axis gonio stage (gonio) stage 13, rack pinion-type XY stage 14, and B-axis gonio stage 15 (both of which are manual) are arranged on lower stone platform 2. The lens 11 can be rotated around the Y-axis at the B-axis goni stage 14 and installed at an angle, and the rotation direction around the X-axis can be adjusted at the A-axis goni stage 13. In addition, the position in the XY axis direction of the lens 11 can be finely adjusted by the XY stage 14. The jig 12 includes a taper spacer 16 fixed to the B-axis gonio stage 15 and an upper plate 17 disposed on the taper spacer 16. The lens 11 is detachably attached to the upper plate 17 by a support claw 18. The upper surface of the taper spacer 16 has the inclination of 10 degrees with respect to the horizontal. The upper plate 17 is supported by three points with respect to the upper surface of the tapered spacer 16. The upper plate 17 with respect to the taper spacer 16 has two positioning pins 19 for positioning the angular position of the C axis with respect to the upper surface of the taper, and is detached from the positioning pins 19 and mechanically rotated. The upper plate 17 is configured to be rotatable mechanically by 90 degrees with respect to the tapered spacer 16.

The control and computing device 21 constituted by the computer and its peripheral device controls the operation of the entire measuring device 1 based on the program stored in advance, performs the measurement, and executes various operations on the measurement data. Specifically, the control device 21 is configured to Z the entire probe unit 100 such that the force acting from the surface of the lens 11 as a measurement object with respect to the stylus 101 at the lower end of the probe 103 is constant. While applying a servo for feedback control in the direction, the probe unit 100 moving in the Z direction is sequentially scanned in the X or Y direction by the X-axis stage 3 and the Y-axis stage 4. At a supply pitch in the XY direction, a point group of shape data is acquired and stored. The control and computing device 21 is connected to, for example, a display, an output device 22 serving as a peripheral device thereof, and an input device 23 including a keyboard, a mouse, and the like. The output result of the operation of the control device 21 or the like is output or displayed by the output device 22, and the command to the control device 21 can be input by the input device 23.

Below, the three-dimensional shape measuring method of this embodiment is demonstrated with reference to the flowchart of FIG. First, the lens 11 is inclined with respect to the lower stone slab 2 (step S3-1). Specifically, as shown in FIG. 6, the lens 11 is provided so that the mark 11a of the lens 11 is on the negative side of the Y axis of the measuring device 1. The mark 11a can be formed using the injection part of the plastic at the time of shaping | molding, the marking at the time of metal mold | die processing, etc. In addition, the lens 11 is installed inclined at an angle with the Y-axis as the rotation center (in the B-axis direction). The inclination of the lens 11 around the Y axis can be adjusted by the B axis gonio stage 15. When the measurable limit angle of the measuring device 1 is 60 degrees and the maximum tilt angle of the lens surface is 80 degrees, when the tilt angle of the lens 11 around the Y axis is 20 degrees, the negative side of the lens surface in the X-axis direction The part on the X-axis of a part can suppress the angle of a measurement surface within the measurable limit angle of the measuring device 1, and three-dimensional measurement becomes possible.

Next, a measuring NC path is set (step S3-2). Referring to FIG. 6, the measurement NC path includes a measurement path in the X-axis direction (solid line L11) and a measurement path in the Y-axis direction (dashed line L12). The measurement path L11 in the X-axis direction is a straight line in the X-axis direction along the cross section of the axis passing through the vertex position Pt (the point in which the Z-axis position is the highest point) of the lens 11 in a state inclined at an angle to the B-axis. Let's do it. The measurement path L22 in the Y-axis direction is a straight line in the Y-axis direction along the cross section of the axis passing through the vertex position Pt of the lens 11 in a state inclined at an angle to the B-axis. In addition, the measurement paths L11 and L12 in the X-axis and Y-axis directions are set so as to fall within the range of the maximum inclination angle of the measurement when measuring the lens surface inclined around the Y-axis.

Subsequently, centering is performed to move the stylus 101 to the vertex position Pt of the lens 11 while maintaining the state facing obliquely around the Y axis (step S3-3). This centering is performed by moving the stylus 101 in the XY axis direction so that the stylus 101 is at the lens vertex position Pt by the XY stages 3 and 4.

Next, measurement and storage of the measurement data are executed (step S3-4). Specifically, the stylus 101 is moved on the X-axis direction and the Y-axis direction along the aforementioned measurement paths L11 and L12. First, the apex position Pt of the lens 11 in an oblique position is set as a starting point of the measurement, and the axial image and the lens (in the X-axis direction are within the range of the maximum tilt angle of the measuring device 1). 11) Scan the stylus 101 while applying the servo to make the operating force constant, and measure the position (XYZ coordinate) of the stylus 101 at that time sequentially and store it as a measurement data group in the X-axis direction. Preserve In addition, the apex position Pt of the lens 11 in an oblique position is set as a starting point of the measurement, and the axial image and the lens (the axial image in the Y-axis direction are within the range of the maximum tilt angle of the measuring device 1). 11) Scan the stylus 101 while applying the servo to make the operating force constant, and measure the position (XYZ coordinate) of the stylus 101 at that time sequentially and store it as a measurement data group in the Y-axis direction. Preserve

After that, an alignment process for calculating the difference between the measurement data group in the X-axis and Y-axis directions and the design formula of the lens 11 is executed (step S3-5). Subsequently, it is determined whether or not the tilt adjustment is necessary based on the result of the alignment process (step S3-6). Specifically, as a result of the alignment process, when the installation deviation in the rotation direction (A axis) around the X axis of the measuring device 1 is large (for example, 1 ° or more), the area around the X axis obtained by the alignment process ( The lens 11 is operated by operating the A-axis gonio stage 13 by an amount corresponding to the amount of rotation of the A-axis) (the amount of rotation around the X-axis necessary for fitting the measurement data group to the design formula of the lens 11). Is rotated around the X axis, and the tilt angle is adjusted so that the installation angle around the X axis of the lens 11 is not inclined to the measuring device 1 (step S3-7). After the tilt adjustment, the process is repeated from the centering to the necessity and unnecessary determination of the tilt adjustment (step S3-6). On the other hand, if the mounting deviation of the lens 11 in the rotation direction around the X axis of the measuring device 1 is sufficiently small as a result of the alignment process (for example, about 10 minutes or less), the attitude set in step S3-1 The measurement of the X-axis direction and the Y-axis direction of the lens 11 at is finished, and the flow proceeds to step S3-8. When this tilt adjustment is no longer necessary, the final measurement data group in the X- and Y-axis directions of the lens 11 measured in the posture set in step S3-1 can be obtained. The measurement data group in the X-axis direction finally obtained is data of the high inclined plane in the negative direction of the X-axis of the lens 11.

In step S3-8, the inclination of the lens 11 is changed in order to change the measurement location on the lens surface. Specifically, the lens 11 is rotated 180 degrees so as to be fixed so that the mark 11a of the lens 11 is on the plus side on the Y axis with respect to the Z axis in the design coordinate system of the lens 11. Rotation of the lens 11 removes the upper plate 17 of the mounting jig 12 from the tapered spacer 16 once, changes the direction of 180 degrees, and then again moves the positioning pin (with respect to the tapered spacer 16). 19) by positioning and attaching.

After changing the inclination of the lens 11, the setting of the measuring NC path (step S3-9) is performed as before the inclination change, and the lens 11 in the rotational direction around the X axis of the measuring device 1 Centering (step S3-10), measurement in the X-axis direction and Y-axis direction, storage of measurement data (step S3-11) and tilt adjustment (step S3-14) are repeated until the installation deviation becomes small enough. The measuring NC path after changing the inclination of the lens 11 is the same as before changing the inclination, and the measuring path in the X-axis direction of the axis passing through the vertex position Pt of the lens 11 in a state inclined at an angle to the B axis is installed. A straight line in the X-axis direction along the cross section, and the measuring path L22 in the Y-axis direction is in a straight line in the Y-axis direction along the cross section of the axis passing through the vertex position Pt of the lens 11 in a state inclined at an angle to the B-axis. It is done. The lens in the posture changed in step S3-8 when the installation deviation of the lens 11 in the rotational direction around the X axis of the measuring device 1 becomes small enough, and the tilt adjustment becomes unnecessary in step S3-13. The measurement data group of the final X-axis and Y-axis directions of (11) can be obtained. The measurement data group in the X-axis direction finally obtained is data of the positive direction high inclined plane of the X-axis of the lens 11.

Subsequently, coordinate transformation, alignment processing, and data combining are performed on the measurement data groups in the X-axis direction and the Y-axis direction measured in each of the two postures (step S3-15). Hereinafter, with reference to FIG. 4, coordinate transformation, alignment, and data synthesis are demonstrated concretely.

First, an offset amount with respect to the lens design coordinate system (when the lens 11 is installed horizontally) of the lens 11 installed at an inclined angle (steps S3-1 and S3-8) is calculated (steps). S4-1). The measurement data group in the case where the lens 11 is provided at an angle is in a state indicated by a dotted line in FIG. 7A. Thus, the offset at the tilting installation position in the design formula in the lens design coordinate system, that is, the vertex offset positions Xtoff, Ytoff, and Ztoff of the lens shown in Fig. 7B are calculated.

Subsequently, the measurement data (steps S3-1 to S3-7 and steps S3-8 to S3-14) measured in the two obliquely installed stages (steps S3-1 and S3-8), that is, the sloped installation The position measurement data is coordinate-converted to the offset amount calculated in step S4-1 (step S4-2). Specifically, based on the offset amount calculated in step S4-1, all inclination-mounted position measurement data is first rotated only by B, and then the vertex position in the lens design coordinate system and the lens are installed at an angle. The translation is performed by the difference amount of the vertex position Pt, and coordinate-converted as shown by the dotted line in FIG. 7B.

Then, as shown in FIG. 9, coordinate conversion about a Z axis | shaft is performed by the amount of the lens 11 rotated around the Z axis | shaft at the time of a measurement, and it carries out coordinate conversion to a design position (step S4-3). ).

The measurement data after the coordinate transformation of steps S4-2 and S4-3 includes an offset (probe R offset) due to having a finite radius with the stylus 101 at the bottom of the probe 102. Thus, in step S4-4, the design formula of the lens 11 is executed after the correction probe R for removing the offset of the probe R amount is performed on the measurement data after the coordinate transformation of steps S4-2 and S4-3. The alignment process is executed in a design formula that minimizes the difference with the shape and finds the difference at that time. Hereinafter, the alignment process by the design formula of step S4-4 is demonstrated with reference to FIG.

First, manual movement calculation is performed (step S5-1). Specifically, the measurement data and the design formula are displayed graphically on the display of the output device 22, and the measurement data is parallel-moved or rotated so as to match the design formula as much as possible by the operation of the input device 23.

When the calculation of the RMS value to be described later in step S5-2 is the first time, that is, when the loop of steps S5-1 to S5-8 is executed for the first time, the cumulative alignment result described later is not calculated, so that step S5-3 is not executed. The probe R correction of step S5-4 is executed.

The procedure of probe R correction (step S5-4) is demonstrated with reference to FIG. In Fig. 8, the measurement obtained by scanning at a predetermined sampling pitch in the X-axis direction with a lens coordinate system while focusing on the lens 11 with respect to the stylus 101 having a spherical tip shape. The data group is represented by dashed line L31. When the shape (X, Y, Z) of the lens surface is represented by Z = f (X, Y), the inclination in the normal direction of the lens surface at the probe center coordinate Xm at the probe position of FIG. 8 is indicated by the arrow V11. Appears. From the probe center position at Xm as a starting point, the intersection X 'between the vector V12 in the reverse direction of the arrow V11 and the lens surface can be obtained by combining the vector V12 and Z = f (X, Y). However, this X 'point is at a position away from the true point of contact between the stylus 101 and the lens surface. In order to reduce this calculation error, the vector V13 in the opposite direction to the normal of the lens surface at the X position of X 'is calculated, and the intersection point X' with the lens surface when the vector V13 is based on the probe center position at Xm. '(X' can be obtained by combining the vectors V13 and Z = f (X, Y)). Subsequently, X '' is newly determined as X ', and X' is obtained again. This calculation is repeated until the difference between the distance between the two points X 'and X' 'becomes smaller than the resolution of the measuring device 1, and is calculated as a value close to the true contact point.

After the probe R correction, the data in the effective radius ER region of the lens 11 set in advance is extracted from the probe R corrected measurement data group (step S5-5). That is, in this embodiment, the target area (alignment effective diameter) of alignment with a design formula is all the measurement data contained in the effective radius ER of the lens 11.

Next, the alignment amount of the XYZAB axis is calculated by the least square method (step S5-6). Specifically, the sum of the squares of the differences between the respective points of the probe R-corrected measurement data group extracted in step S5-5 and the design shape of the lens 11 (the point corresponding to the design formula of the lens 11). By performing the least square method to minimize the alignment amount dX, dY, dZ, X and Y which are deviations of the translational direction of the X, Y, and Z axes from the extracted probe R-compensated measurement data group and the design shape. The amount of alignment dA, dB, which is a deviation of rotation about the axis, is calculated. The calculated amount of alignment dX, dY, dZ, dA, dB is stored as a cumulative alignment result.

Next, the coordinates of the probe R corrected measurement data extracted in step S5-4 are coordinate-converted by the alignment amounts dX, dY, dZ, dA, and dB calculated in step S5-6 (S5-7).

Next, the RMS value which is the sum of squares of the difference between the measurement data group coordinate-converted by the alignment amount and the design shape in step S5-7 is calculated and stored (step S5-8).

The calculation result of the RMS value before the process from manual movement calculation (step S5-1) to calculation of RMS value (step S5-8), and the variation rate of the calculation result of this RMS value are predetermined | prescribed. It repeats until it becomes smaller than a range (step S5-9). When the loop of steps S5-1 to S5-8 is executed after the second time, the cumulative alignment result (last time) before probe R correction (step S5-4) after the manual movement calculation (step S5-1). Coordinate transformation by the alignment amount dX, dY, dZ, dA, dB calculated in step S5-6 at the time of loop execution is performed (step S5-3).

Although the alignment amounts dX, dY, dZ, dA, and dB calculated by the least square method in step S5-6 are not exact solutions but approximate solutions, the processes of steps S5-1 to S5-8 are repeated. By this, more accurate alignment processing becomes possible.

When the rate of change of the calculation result of the RMS value in step S5-9 becomes smaller than the predetermined range, the alignment process to the design formula is completed. At this time, the probe R-corrected measurement data group coordinate-converted into alignment amounts dX, dY, dZ, dA, and dB in the previous step S5-7 becomes measurement data (alignment data) aligned by the final design formula.

After completion of the alignment in the design formula (steps S4-3 in FIG. 4 and FIG. 5), as shown in FIG. 9, the alignment data is rotated by the amount of the lens 11 rotated around the Z axis during the measurement. Coordinate transformation around the Z axis is performed to coordinate alignment data to the measured position in the lens coordinate system.

After the processing of steps S4-1 to S4-4 is calculated for both directions (all of the inclination arrangements of the lens 11) (step S4-5), the design shape of the lens 11 for both directions and The difference with the shape of the measured lens 11 is calculated | required, the obtained data are synthesize | combined and stored, and it outputs to the output apparatus 22 as needed (step S4-6).

The graph of the calculation result of 1st Embodiment is shown in FIG. The horizontal axis of this graph is in the X-axis, the unit is mm, and the vertical axis is the difference Zd (= (measurement data)-(design value)) in the Z direction with the design shape, and the unit is mm. As shown in this FIG. 10, the shape evaluation of the lens surface which has the inclined surface of 80 degree is enabled by the three-dimensional shape measuring method of this embodiment.

In the first embodiment, when the measurement was performed, the lens was rotated 180 degrees and measured in two directions to measure data on the X axis, but the rotation of the lens 11 was carried out by 90 degrees, similarly to the data on the X axis, Y Data on the axis can be obtained, and cross-sectional data on the X and Y axes of the lens 11 can be measured. That is, in 1st Embodiment, a cross section with respect to the X axis of the design coordinate system of the lens 11 by performing a measurement about the two installation states which rotated the lens 11 by 180 degree angle increments about the Z axis of the design coordinate system. Although data has been obtained, the cross-section of the X and Y axes of the design coordinate system of the lens 11 is measured by performing measurements on four installation states in which the lens 11 is rotated by an angle increment of 90 degrees about the Z axis of the design coordinate system. You can get data.

(2nd embodiment)

Most of the lenses used in portable cameras and DSCs (digital still cameras) are axial symmetric aspherical lenses. However, when the deviation between the design shape and the actual shape is large, the alignment data may be pulled instead of being horizontal. This phenomenon occurs because the data scores are not symmetrically distributed about the design center. Also in the measurement result of FIG. 10 mentioned above, in the area | region of about +/- 0.4mm on an X-axis, the measurement data does not overlap in the center part and becomes unnatural data by the said phenomenon.

On the other hand, when analyzing the other data shown in FIG. 11, since the data which should be originally symmetric with respect to the zero point of the lens design coordinates is on the negative side of the X axis, the positive direction of the X axis is indicated by the solid line L41. This data is taken down. From the data of this FIG. 11, the data whose data score becomes symmetrical about X = 0 from lens design coordinates is extracted, and the alignment result in this extracted data is shown in FIG. When the measurement data is extracted such that the data score is symmetrical at the center, the alignment data is also substantially symmetrical to the left and right as shown by the solid line L42, resulting in data that is actually followed.

When the aspherical amount of the lens shape is large, accurate alignment of the design shape can be performed by using the measurement data group extracted from the central symmetry area (symmetry area CER) in the lens design coordinates. However, when the aspherical amount is not sufficient, the alignment in the X axis direction and the rotation around the Y axis cannot be aligned. This point will be described below with reference to FIGS. 13A to 13C.

In the case of a lens surface having a large aspherical surface amount shown in Fig. 13A, since the design shape (solid line) of the lens surface is a shape different from the spherical surface, when moving to superimpose the measurement data group (dotted line) on the lens surface on the design shape, X The translational movement in the axial direction and the rotational movement angle around the Y-axis can be accurately determined.

However, in the case of the lens surface having a small aspherical surface shown in Fig. 13C, since the design shape (solid line) of the lens surface is close to the spherical surface, when moving to superimpose the measurement data group (dotted line) on the lens surface on the design shape, X It is difficult to separately determine the translational movement in the axial direction and the rotational movement around the Y axis.

In addition, as shown in Fig. 13B, depending on the design shape of the lens, the shape of the center portion of the lens is close to the spherical surface, and there may be a case where the aspherical amount is large in the outer portion of the lens (the aspherical amount is medium). In this case, when moving the measurement data group (dotted line) of the lens surface to overlap the design shape (solid line), the measurement data of the entire lens surface can be used to accurately calculate the translational movement in the X-axis direction and the rotational movement around the Y-axis. Can be. However, when using the measurement data group only in an area with a small aspherical surface in the vicinity of the center, it is difficult to obtain by dividing the translational movement amount in the X axis direction and the rotational movement angle around the Y axis.

The three-dimensional measurement method of the second embodiment considers the symmetry of the data score centering on the above two points, that is, X = 0 or Y = 0 in the lens design coordinates, and correspondence to various aspherical lenses.

The three-dimensional measurement method of this second embodiment is the same as that of the first embodiment described with reference to FIG. 3, but the specific processes from coordinate transformation to data synthesis (step S3-15 in FIG. 3) differ.

FIG. 14 shows a process from coordinate transformation in the second embodiment to data synthesis (step S3-15 in FIG. 3). In this FIG. 14, calculation of the offset amount of the installation position in a design formula, coordinate transformation of the measurement data based on it (step S14-1, S14-2), and the C-axis of the alignment data according to the installation direction of the lens 11 The rotation in the direction (step S14-3) and the processes up to data synthesis (S14-8 and S14-9) are similar to those in the first embodiment (steps S4-1 to S4-3 and S4- in FIG. 4). 5, S4-6).

 1st Embodiment after calculation of the offset amount of the installation position on a design formula, coordinate transformation (step S14-1, S14-2) of measurement data based on it, and rotation in the C-axis direction of alignment data (step S14-3) As in Fig. 5, the alignment effect is the total data included in the effective radius ER of the lens 11, and the alignment process according to the design formula for minimizing the difference with the design shape of the lens 11 to obtain the difference at that time. Run an iterative calculation. If the rate of change of RMS converges within the predetermined range in step S14-4, the process proceeds to step S14-5.

In step S14-5, the alignment amount dY and dA of the Y-axis and the A-axis are fixed to the value calculated in step S14-3, the coordinates of the measurement data are converted into dY and dA, and then the alignment effective diameter is symmetrical. It is set in the area CER and iterative calculation of the alignment process in the design formula is performed to calculate dX ', dB'. When the rate of change of the RMS converges within the predetermined range in step S14-5, the alignment is completed and the process proceeds to step S14-8. On the other hand, if the rate of change of RMS does not converge within the predetermined range in step S14-5, the process proceeds to step S14-6. In step S14-6, the alignment amount dY, dA, and dX of the Y-axis, the A-axis, and the X-axis are fixed to the value calculated in step S14-4, and the coordinates of the measurement data are converted into dY, dA, and dX, and then alignment is effective. The diameter is set in the symmetrical area CER, repeat calculation of the alignment process in the design formula is performed to calculate dB ', and the alignment is completed.

If the rate of change of RMS does not converge within the predetermined range in step S14-4, the process proceeds to step S14-7. In step S14-7, the alignment amounts dY and dX of the Y-axis and the X-axis are fixed to the values calculated in step S14-4, coordinate coordinate conversion of the measurement data points is performed by dY and dX, and then the alignment effective diameter is set in the symmetry area CER. By repeating the alignment process in the design formula, dB 'is calculated to complete the alignment.

In FIG. 14, when alignment is completed via step S14-5 from step S14-4, it corresponds to the case where the aspherical amount of the lens 11 is large (FIG. 13A). In addition, when alignment is completed through step S14-5 and S14-6 from step S14-4, it corresponds to the case where the aspherical amount of the lens 11 is moderate (FIG. 13B). In addition, when alignment is completed via step S14-4 through S14-7, it corresponds to the case where the aspherical amount of the lens 11 is small (FIG. 13C). Below, the process content of step S14-4-S14-7 is demonstrated concretely.

15 shows details of step S14-4 of FIG. Fig. 15 shows alignment in the design formula in the first embodiment except for whether the rate of change of the RMS value falls within a predetermined range by iterative calculation (step S4-3, Fig. 5). Same as

First, the counter of the number of repetition counts is set to 0, which is the initial value (step S15-1). Next, the counter is incremented by one (step S15-2).

Subsequently, a manual movement calculation is performed (step S5-1). Specifically, the default values of the alignment amounts dX, dY, dZ, dA, and dB are 0, but the measurement data and design formula are displayed graphically on the display of the output device 22, and the The measurement data is translated or rotated so as to conform to the design formula by operation.

In the case of N-1 (first execution of the loop of steps S15-2 to S15-10) in step S15-4, probe R correction is performed without executing step S15-3 (step S15-6). This probe R correction is the same as the probe R correction (step S5-4 in FIG. 5) in the first embodiment described with reference to FIG.

After the probe R correction, the data in the area of the effective radius ER of the lens 11 is extracted from the probe R-corrected measurement data group (step S15-7), and the alignment amount of the XYZAB axis is calculated by the least square method (step S5). -8). Specifically, a minimum square method is performed by minimizing the sum of squares of the differences between each point of the probe R-corrected measurement data group extracted in step S15-7 and the design shape of the lens 11, and extracted. Probe R Compensation Alignment amount dX, dY, dZ, deviation of rotation around X and Y axes, deviation of translational direction of X, Y and Z axes from the measured data group and design shape Calculate The calculated amount of alignment dX, dY, dZ, dA, dB is stored as a cumulative alignment result. Subsequently, the alignment amount dX, dY, dZ, dA, and dB calculated in step S15-8 is coordinate-converted to the probe R corrected measurement data group extracted in step S15-7 (S15-9). Moreover, the RMS value which is the sum of squares of the difference between the measurement data group coordinate-converted by the alignment amount and the design shape is calculated and stored (step S15-10).

The process of steps S15-2 to S15-10 is repeated until the rate of change of the RMS value becomes smaller than the predetermined range (step S15-11). When the loops of steps S15-2 to S15-10 are executed after the second time, the cumulative alignment result (last loop) after the manual movement calculation (step S15-3) and before the probe R correction (step S15-6). Coordinate transformation by the alignment amount dX, dY, dZ, dA, dB) calculated in step S5-6 at the time of execution is performed (step S15-5).

If the rate of change of the RMS value becomes smaller than the predetermined range (when the RMS value converges) until the number of iterations of the loops of steps S15-2 to S15-10 is less than N times, the process proceeds to step S14-5 (Fig. 16). When the number of repetitions of the loop exceeds N times (when the RMS value does not converge), the process proceeds to step S14-7 (Fig. 18) (steps S15-11, S15-12).

FIG. 16 shows the details of step S14-5 of FIG. In FIG. 16, when the RMS value converges by the alignment process by the design formula which made the alignment effective diameter the whole data in the effective radius ER of the lens 11 (solution of alignment amount dX, dY, dZ, dA, dB) ), The measurement data group of only a small area (symmetric area CER) near the center of the lens 11 is used as an object, and the alignment amounts dX 'and dZ' of the remaining axes other than the alignment amounts dY and dA. Calculate new dB '. The measurement data (step S14-2) coordinate coordinate-converted to the offset amount of the mounting position in the design formula is obtained by the alignment amounts dY, dA, dX ', dZ', and dB 'obtained. That is, in the processing of Fig. 16, the alignment amounts of the Y-axis and the A-axis are fixed to values calculated by using the entire data as an object, and the alignment amounts of the remaining axes are calculated using the measurement data of the symmetrical area CER. By the process of FIG. 16 (step S14-5 of FIG. 14), even if the score of a measurement data group is unevenly distributed with respect to the center of design data as demonstrated with reference to FIG. The shape of the lens 11 can be measured with high accuracy by removing the influence of the deviation of the mounting position of the lens 11. Hereinafter, the process of FIG. 16 is demonstrated concretely.

First, a counter of the number of iterations is set to 0, which is the initial value (step S16-1). Next, the counter is incremented by one (step S16-2).

Next, coordinate data is converted into coordinates using the alignment amounts dY and dA obtained in step S14-3 (step S16-3). The measurement data to be subjected to this coordinate transformation is coordinate transformation (steps S14-1, S14-2) based on the offset amount of the installation position on the design formula and rotation in the C-axis direction along the installation direction of the lens 11 ( Step S14-3) Completed measurement data.

In the case of N-1 (first execution of the loop of steps S16-2 to S16-10) in step S16-4, probe R correction is performed without executing step S16-3 (step S16-6). This probe R correction is the same as the probe R correction (step S5-4 in FIG. 5) in the first embodiment described with reference to FIG.

After the probe R correction, the data in the symmetric region CER is extracted from the probe R corrected measurement data group (step S16-7), and the alignment amount of the XZB axis is calculated by the least square method (step S16-8). Specifically, a minimum square method is performed by minimizing the sum of squares of the differences between the respective points of the probe R-corrected measurement data group extracted in step S16-7 and the design shape of the lens 11, and extracted. The amount of alignment dX ', dZ', dB 'between the probe R-corrected measurement data group and the design shape is calculated. The calculated amount of alignment dX ', dZ', dB 'is stored as a cumulative alignment result. Subsequently, coordinate measurement is carried out by the alignment amounts dX ', dY, dZ', dA, and dB '(S16-9). The object of this coordinate transformation is the probe R corrected measurement data (all data in the effective radius ER) obtained in step S15-6 in FIG. 15. In addition, the RMS value which is the sum of squares of the difference between the measured data group coordinate-converted by the alignment amount and the design shape in the symmetric area CER is calculated and stored (step S16-10).

The process of steps S16-2 to S16-10 is repeated until the rate of change of the RMS value becomes smaller than the predetermined range (step S16-11). When the loops of steps S16-2 to S16-10 are executed after the second time, after the coordinate transformation (step S16-3) by the alignment amounts dY and dA, the accumulated alignment result before the probe R correction (step S15-6). Coordinate transformation by (alignment amount dX ', dY, dZ', dA, dB 'calculated in step S5-6 at the time of last loop execution) is performed (step S16-5).

If the rate of change of the RMS value becomes smaller than a predetermined range (when the RMS value converges) until the number of iterations of the loops of steps S16-2 to S16-10 is smaller than N, the alignment of the design shape of the measurement data group is completed. Therefore, the process proceeds to step S14-8 of FIG. 14, and when the number of loop repetitions exceeds N times (when the RMS value does not converge), the process proceeds to step S14-6 (FIG. 17) (step S16). -11, S16-12).

17 shows details of step S14-6 of FIG. FIG. 17 shows the amount of alignment on the Y-axis and the A-axis when the RMS values do not converge in FIG. 16 (step S14-4 in FIG. 14), and the remaining alignment amount is determined by the alignment using the symmetry area CER as the alignment effective radius. If it does not, the same processing is further performed by fixing the alignment amount dX of the X axis. Even when the shape of the center portion of the lens described with reference to FIG. 13B is close to the spherical surface by the process of FIG. The shape of the lens 11 can be measured with high accuracy by eliminating the influence of the installation deviation of the lens 11 on the measuring device 1. Hereinafter, the process of FIG. 17 is demonstrated concretely.

First, measurement data is coordinate-converted using the alignment amounts dY, dA, and dX obtained in step S14-3 (step S17-1). The measurement data to be subjected to this coordinate transformation is coordinate transformation (steps S14-1, S14-2) based on the offset amount of the installation position on the design formula and rotation in the C-axis direction along the installation direction of the lens 11 ( Step S14-3) Completed measurement data.

In the case where the calculation of the RMS value is the first time (first execution of the loop of steps S17-1 to S17-8) in step S17-2, the probe R correction of step S17-4 is performed without executing step S17-3. Run This probe R correction is the same as the probe R correction (step S5-4 in FIG. 5) in the first embodiment described with reference to FIG.

After the probe R correction, the data in the symmetric region CER is extracted from the probe R corrected measurement data group (step S17-5), and the alignment amount of the ZB axis is calculated by the least square method (step S17-6). Specifically, a minimum square method is performed by minimizing the sum of squares of the differences between the respective points of the probe R-corrected measurement data group extracted in step S17-5 and the design shape of the lens 11, and extracted. The amount of alignment dZ ', dB' between the probe R-corrected measurement data group and the design shape is calculated. The calculated amount of alignment dZ ', dB' is stored as a cumulative alignment result. Subsequently, the measurement data group is coordinate-converted by the alignment amounts dX, dY, dZ ', dA, and dB' (S17-7). The object of this coordinate transformation is the probe R corrected measurement data (all data in the effective radius ER) obtained in step S15-6 in FIG. 15. Furthermore, the RMS value which is the sum of squares of the difference between the measurement data group coordinate coordinate-converted by the alignment amount and the design shape of the data in the symmetric area CER is calculated and stored (step S17-8). The above process is repeated until an RMS value can be obtained in step S17-9. When the loop of steps S17-2 to S17-8 is executed after the second time, after the coordinate transformation (step S17-1) by the alignment amounts dY, dA, and dX, before the probe R correction (step S17-4), the accumulated alignment is performed. Coordinate transformation is performed by the result (alignment amount dX, dY, dZ ', dA, dB' calculated in step S5-6 at the time of the previous loop execution) (step S17-3).

18 shows details of step S14-7 of FIG. FIG. 18 shows the RMS value when the RMS value does not converge in FIG. 15 (step S14-4 in FIG. 14), that is, the alignment process is performed by the alignment formula according to the design formula in which the alignment effective diameter is the entire data in the effective radius ER of the lens 11. This convergence (when the solution of alignment amount dX, dY, dZ, dA, dB cannot be obtained) is the process. By the process of FIG. 18 (step S14-7 of FIG. 14), even if the aspherical surface amount of the lens surface described with reference to FIG. 13C is small, the influence of the deviation of the installation of the lens 11 with respect to the measuring device 1 as much as possible is possible. By removing, the shape of the lens 11 can be measured with high precision.

First, in step S18-1, the alignment amounts dA and dB are set to 0, and the remaining alignment amounts dX ', dY', and dZ 'are obtained from the alignment with the alignment effective radius as the total data. The calculation procedure of this step S18-1 is the same as that of FIG. In the processing of steps S18-2 to S19-10 in Fig. 18, the alignment amounts of the Y-axis and the X-axis are fixed to dX 'and dY' calculated by using the entire data in step S18-1, and only the symmetrical area CER is measured. It is similar to the processing of steps S17-1 to S17-9 in Fig. 17, except that the alignment amounts dZ ", dA ", and dB "

19 shows an example of the calculation result of the second embodiment. FIG. 19 shows the case where the RMS values converge in step S14-5 in FIG. The horizontal axis of the graph is the X axis, the unit is mm, the vertical axis is the difference Zd (= (measurement data)-(design)) in the Z direction with the design shape, and the unit is mm. As shown in this FIG. 10, by the three-dimensional shape measuring method of this embodiment, shape evaluation of the lens surface which has an inclined surface of 80 degrees can be performed so that data may overlap in the center part of a lens.

In the second embodiment, at the time of measurement, the lens was rotated 180 degrees and measured in two directions to measure the data on the X axis, but the rotation of the lens 11 was carried out by 90 degrees, similarly to the data on the X axis, Y The data on the axis can be obtained, and the cross-sectional data on the X and Y axes of the lens 11 can be measured. 20 shows the calculation result in this case.

(Third embodiment)

When the lens 11 is an aspherical lens having a diameter of about 2 mm and a spherical radius of about 1.03 mm when used in a mobile phone with a camera or the like, the aspheric amount of the lens surface relative to the spherical surface Some are only a few μm long. In the case of such a lens 11, when a mold is manufactured in a design shape and then the lens 11 is molded using a plastic material or the like, shrinkage at the time of molding causes the order of several μm, which is the same order as the aspheric amount. Distortion may occur. In this case, the design shape is estimated from the actual shape, coordinate measurement of the measurement data installed and measured in the measuring device 1 using the estimated design shape, and alignment is performed to precisely correct the three-dimensional shape including the high inclined portion. It can be measured. Below, it demonstrates using a specific example.

With reference to FIG. 21, the design formula of an axial symmetric aspherical lens is represented by following formula (4), for example. This design formula consists of the terms of the spherical surface (spherical radius R), the conic coefficient K representing the characteristics of the ellipse and the hyperbolic surface, and the aspherical coefficient Ai (about i = 1 to 20) representing the difference between the spherical surfaces.

(Equation 4)

R: spherical radius

K: conic coefficient

Ai: Aspherical Modulus

X: X coordinate direction coordinate value

Y: Y coordinate direction coordinate value

Here, when the measurement data group is aligned with the design shape, the distortion shape error changes the value of the spherical radius R because only the spherical radius R is changed in the design formula of Equation (4). Then, with respect to the design shape in which the spherical radius R is changed, the best fit R value at which the RMS value is minimum is calculated by aligning the measurement data group. 22 shows the results of the difference between the design shape using the calculated best fit R and the measurement data point group. FIG. 22 has a smaller error in the Zd direction than FIG. 19 aligned with the original design shape, and has a design formula that fits the design shape.

Using the obtained best fit R value as a design shape, the conversion amount of coordinate XYZAB in each state is calculated and stored in the order of 1st Embodiment or 2nd Embodiment. Thereafter, the design shape is returned to the original design shape, and the coordinate transformation amount stored therein is used to perform sequential coordinate transformation and probe R correction processing to display three-dimensional shape data as a difference between the measurement data group and the original design shape. . Thereby, coordinate transformation and probe R correction from the state installed at an angle can be performed more accurately, and high precision measurement of a high inclined surface can be performed.

In addition, in order to more accurately calculate the coordinate conversion amount of the measurement data group and to perform the connection at the overlap portion of the high precision center part, the design shape of the measurement data group may be just estimated. For example, when the design expression of the axial symmetric aspherical surface is represented by equation (4), in addition to the above-described calculation of the best fit R parameter, the RMS value of aligning the measurement data group with respect to the term Ai of the aspherical surface is minimized. Obtain the estimated design geometry corrected accordingly. Using the obtained estimated design shape as the design shape, the conversion amount of the coordinates XYZAB in each state is calculated and stored in the order of the first embodiment or the second embodiment. After that, the design shape is returned to the original design shape, and the coordinate conversion amount and the probe R correction process are sequentially performed at the stored coordinate conversion amount to display three-dimensional shape data as the difference between the measurement data group and the original design shape. Thereby, coordinate transformation and probe R correction from the state installed at an angle can be performed more accurately, and high precision measurement of a high inclined surface can be performed.

In addition, the output data of FIG. 10 processed in the order of the first embodiment or the second embodiment may be manually adjusted in order to evaluate the data in a symmetrical manner by matching the overlap of the central portion. Specifically, while monitoring the output data of FIG. 10 on the display of the output device 22, the rotation around the Y axis and the horizontal movement in the Z axis direction with respect to the data in the left area of the two-way measurement data are input device 23. Run manually by Further, rotation about the Y axis and horizontal movement in the Z axis direction are manually performed on the data in the right area. This manual adjustment causes the two data to overlap and overlap each other in the central region of the symmetric CER of the two data, so that even if a part of the measurement data contains noise data due to dust on the lens surface, etc. The high-precision measurement of the high inclined surface can be performed so that the data may overlap.

In addition, in order to evaluate the data with good symmetry by matching the overlapping of the central portions, the movement and synthesis using the least square straight line are performed on the output data of FIG. 23 processed in the order of the first embodiment or the second embodiment. You may also Specifically, the following processing is performed on two-way measurement data, that is, the measurement data group DL in the left area and the measurement data group DR in the right area, in the symmetrical area CER in which measurement data are acquired symmetrically with respect to the center of the design shape. Run

1) The center portion of each measurement data DL and DR is linearly approximated by the least square method in the XZ plane (symbols L51 and L52 in Fig. 23).

2) The amount of rotation about the Y axis (inclined to the X axis of the approximate straight lines L51 and L52) and the amount of movement in the Z axis direction are calculated so that the two approximated straight lines L51 and L52 overlap with the X axis, respectively.

3) The two measurement data groups DL and DR are rotated and moved horizontally in the amount of rotation around the Y axis and the horizontal movement amount in the Z axis direction calculated in 2) to synthesize the measurement data groups DL and DR.

By the above processing, even when noise data resulting from dust on the lens surface or the like is included in a part of the measurement data groups DL and DR, the data of each center portion is superimposed without performing manual adjustment, so that the high inclination surface is high precision. Degree measurements can be performed.

(4th Embodiment)

In the first and second embodiments, the probe 102 is positioned in the X and Y axis directions in the coordinate system of the measuring device 1 with respect to the lens 11 provided at an angle, in the cross direction when viewed in the XY plane. Injected measurement results were processed. In order to evaluate the lens surface as a planar shape, the stylus 101 is moved in the XY direction on the lens surface in a state in which the focus is added to the probe 102 by the planar scanning path on the writing as shown in FIG. 24. Scanning may be performed continuously to obtain a planar measurement data group. In FIG. 24, code | symbol A1 represents the effective area of the lens 11, and code | symbol A2 represents the area | region which the probe 102 of the measuring device 11 can follow the surface shape.

This planar measurement data group is separated into two groups, the X-axis-based measurement data (solid line) group and the other external data group (dashed line). In the first embodiment and the second embodiment, the measurement data on the X axis is executed as the measurement data group (solid line) on the X axis, and the measurement data on the Y axis is the outer data group (dashed line). High-precision measurement of a high inclined surface can be performed as surface data.

(Fifth Embodiment)

In order to verify the measurement accuracy of the measuring device 1 in performing the three-dimensional shape measuring method of 1st Embodiment-4th Embodiment, the masterwork 31 as shown to FIG. 25A, 25B is shown. It is preferable to use. The master work 31 has an elliptical shape 31a of Rz in the XY direction, a radius in the XY direction, rotationally symmetrical to the Z-axis, and a nickel plated material such as super steel. It consists of.

At this time, the elliptic portion 31a is represented by the following design formula. First, the design formula in the case where the symmetry axis is provided vertically, that is, in the Z-axis direction, is as shown in the following formula (5).

(Eq. 5)

The design formula at the time of providing the XZ plane horizontally becomes as following formula (6).

(Equation 6)

The design formula at the time of providing a YZ plane horizontally becomes as following formula (7).

(Eq. 7)

By having ellipse-shaped part 31a, as shown to FIG. 25A, it is possible to evaluate the shape from 0 degree | times to 60 degree vicinity from the upper side of a Z-axis, and to confirm shape precision. Then, as shown in FIG. 25B, it is possible to rotate 90 degrees around the X axis, evaluate the shape from the upper side of the Z axis to the vicinity of 0 degree to 60 degree of a masterwork, and confirm shape accuracy. By checking that the deviation from the design shape of the elliptic portion 31a of the master work 31 in each direction falls within a predetermined value, when viewed in the vertical direction, the axis of symmetry is 0 to 90 °. By the angle, the accuracy verification of the measuring device 1 can be performed.

In the above embodiment, the description has been made by taking the case where the X-axis is a reference, but the method of the present invention can be executed even when the X-axis and the Y-coordinate are replaced with the Y-axis as the reference.

The three-dimensional shape measuring method of the present invention can accurately measure the inclined plane exceeding the measurable inclination angle of the conventional three-dimensional shape measuring device, and is used in optical disk storage devices such as lenses and BDs used in mobile phones with cameras. It is applicable to the use of the lens shape of which the inclination with respect to the optical axis of the lens surface which consists of high inclinations, such as a pick-up lens, becomes high-precision three-dimensional shape.

BRIEF DESCRIPTION OF THE DRAWINGS The perspective view which shows the three-dimensional shape measuring apparatus which implements the three-dimensional shape measuring method of 1st Embodiment.

2 is a schematic side view showing a jig of a lens (measured object).

3 is a flowchart showing a three-dimensional shape measuring method according to the first embodiment.

4 is a flowchart showing details of step S3-15 of FIG.

5 is a flowchart showing details of step S4-4 in FIG.

6 is a schematic perspective view for explaining a measurement path.

7A is a schematic side view illustrating a measurement path before coordinate transformation.

7B is a schematic side view illustrating a measurement path after coordinate transformation.

8 is a schematic diagram for explaining probe R correction.

9 is a conceptual diagram for explaining coordinate transformation in the C axis.

The graph which shows an example of the measurement result of 1st Embodiment.

FIG. 11 is a graph showing another example of the measurement result of the first embodiment (when there is asymmetry in the measurement data score). FIG.

FIG. 12 is a graph showing a result of extracting and aligning data whose symmetry is at the center of the measurement result when the measurement data score has asymmetry. FIG.

It is a schematic diagram which shows the relationship between the measurement data group and a design shape when an aspherical amount is large.

Fig. 13B is a schematic diagram showing the relationship between the measurement data group and the design shape when the aspheric amount is medium;

Fig. 13C is a schematic diagram showing the relationship between the measurement data group and the design shape when the aspherical amount is small.

14 is a flowchart showing a three-dimensional shape measuring method according to the second embodiment.

FIG. 15 is a flowchart showing details of step S14-3 of FIG. 14;

FIG. 16 is a flowchart showing details of step S14-4 in FIG. 14;

FIG. 17 is a flowchart showing details of step S14-5 of FIG. 14;

FIG. 18 is a flowchart showing details of step S14-6 in FIG. 14;

The graph which shows an example of the measurement result of 2nd Embodiment.

20 is a graph showing another measurement result of the second embodiment.

21 is a schematic perspective view for explaining a design formula of an axial symmetric aspherical lens.

The graph which shows an example of the measurement result using the best fit R of 3rd Embodiment.

The graph for demonstrating the superposition using the least square method of 3rd Embodiment.

FIG. 24 is a schematic plan view showing a planar scan of a fourth embodiment. FIG.

25A is a schematic side view of a master work (installing a symmetrical axis in the Z direction).

25B is a schematic side view of the master work (installed horizontally on the XZ plane).

It is a schematic diagram which shows an example of the probe unit of a three-dimensional shape measuring apparatus.

27 is a conceptual view for explaining an example of a conventional three-dimensional shape measuring method.

28 is a conceptual view for explaining another example of the conventional three-dimensional shape measuring method.

It is a schematic diagram for demonstrating the measurement error resulting from rotation about an X axis.

* Description of the sign

1: 3D shape measuring instrument

2: lower stone tablet

3: X-axis stage

4: Y-axis stage

5: upper stone tablet

6: He-Ne laser

7: optical system

8: X-axis mirror

9: Y-axis mirror

11: lens

12: jig

13: A-axis Konio stage

14: XY stage

15: B-axis gonio stage

16: tapered spacer

17: top plate

18: support claw

19: positioning pin

21: control?

22: output device

23: input device

31: Masterwork

31a: elliptic circular part

Claims (9)

Set the measurement object to the first installation state inclined around the Y axis of the three-dimensional measuring instrument, At least one second installation state is caused by rotating the measurement object one or more times from the first installation state by an angular increment of two or less natural numbers of 90 degrees about the Z axis of the measurement object. For each of the first and second installation states, the measurement object surface is measured by the three-dimensional measuring instrument on a straight line in the X-axis direction of the three-dimensional measuring instrument passing through the vertex of the measuring object, and the first measurement data group In addition to acquiring), a second measurement data group is obtained by measuring the surface of the workpiece with the three-dimensional measuring instrument on a straight line in the Y-axis direction of the three-dimensional measuring instrument passing through the vertex of the measuring object, For each of the first and second installation states, A preliminary coordinate transformation for rotating and translating the first and second measurement data groups according to the inclination around the Y axis of the 3D measuring instrument to coordinate transformation of the measuring object in a state where the measuring apparatus is installed horizontally. Run it, The first alignment amount for fitting the first and second measurement data groups in which the preliminary coordinate transformation is performed to the design formula of the measurement object is a rotational direction around the X-axis, Y-axis, Z-axis, and X-axis of the measurement object. A axis | shaft is calculated about the B axis | shaft which is a rotation direction around the Y axis | shaft of the said measured object, Two or three of the first alignment amounts of the X-axis, Y-axis, Z-axis, A-axis and B-axis of the measurement object are selected as fixed alignment amount, A first coordinate transformation is performed for coordinate transformation of the first and second measurement data groups in which the preliminary coordinate transformation has been performed into the fixed alignment amount; X-axis, Y-axis, Z-axis, A-axis and B-axis of the second alignment amount for fitting the first and second measurement data group having the first coordinate transformation to the design formula of the measurement object For axes other than the fixed alignment amount in the Performing a second alignment for coordinate-converting the first and second measurement data groups in which the preliminary coordinate transformation is performed into the fixed alignment amount and the second alignment amount, Calculate a difference between the first and second measurement data groups in which the second alignment is made and the design formula of the measurement object; To synthesize a difference from the design formula for the first and second installation states. 3D shape measurement method. The method of claim 1, The angle increment is 180 degrees, and the second installation state is one 3D shape measurement method. The method of claim 1, The angle increment is 90 degrees, and the second installation state is three 3D shape measurement method. delete delete delete delete delete delete

Images