JP2002122423A - 3D measurement method - Google Patents

Abstract

[PROBLEMS] To provide a three-dimensional measuring method capable of accurately specifying a correction portion of a measured object having a concave-convex surface with respect to a design value. SOLUTION: A measuring step (S2, S2) for measuring X, Y, Z coordinate values of an arbitrary region on the surface of the object having a spherical surface.
3), a first calculation step (S4) of approximating the center coordinates of the spherical surface from the measured X, Y, and Z coordinate values, and the spherical surface based on the design value of the measured object is the measured value of the measured object. A moving step (S7) of moving the center of the spherical surface based on the design value from the center coordinates obtained in the first calculation step so that the spherical surface is superimposed on the spherical surface based on the designed value. A second calculating step (S8) of calculating a difference between the measured value of the device under test and a second calculating step (S8) of calculating a superimposition ratio of the spherical surface based on the design value superimposed by the moving process and the spherical surface which is the measured value of the device under test. 3 (S9) and a display step of displaying the calculation results obtained in the first to third calculation steps.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shape calculated from measured data and a design value of a measured object when the surface of the measured object having a continuous spherical shape having an uneven surface is measured in three-dimensional coordinates. The present invention relates to a three-dimensional measurement method for obtaining a difference (error shape) between the two.

[0002]

2. Description of the Related Art Conventionally, in a polishing step in lens processing, a contact type or non-contact type apparatus is used as a three-dimensional measuring apparatus for three-dimensionally measuring the surface shape of an object to be measured, which is a spherical lens or an aspherical lens. Is used to calculate an error shape between a design value and a measured shape of an object to be measured, and to correct an error from the design value.
In the case of a lens having a mirror surface, the coordinates of the center point of the spherical surface of the DUT at the measurement position can be known with relatively high accuracy, so the accuracy of the error shape from the design value is three-dimensional. It depends on the mounting error on the measuring device. Therefore, with respect to an object to be measured having a mirror-like aspherical surface, Japanese Patent Application Laid-Open No. H11-173835 discloses a method in which three spherical surfaces indicating the mounting position of the object to be measured are provided, and the center point of the spherical surface is measured. A coordinate transformation matrix for transforming a group of measurement points measured in the apparatus coordinate system into a representation of a position in the coordinate system of the measured object is obtained and the coordinates are converted. That is, there is disclosed a method of calculating a mounting error of an object to be measured and calculating a highly accurate error shape from a design value of the object to be measured and measurement data in consideration of the mounting error.

As a method of calculating the diameter value of an object having irregularities using a three-dimensional measuring device, Japanese Patent Laid-Open No.
In Japanese Patent No. 01881, the diameter of an average circle is obtained from the measured circular cross-sectional data by the least squares method, and the sum of measurement points arranged at positions facing each other across the center point is defined as a diameter value, which is measured. A method is disclosed in which an abnormal value is detected by comparing all the diameter values for all data, and an average diameter value is calculated excluding the abnormal value.

[0004]

However, in the above-mentioned conventional example in which an aspherical surface is used as in the former case, a mirror surface is used, and an object to be measured having no mirror surface such as a spherical lens having an uneven surface is used. In this case, there is a problem that the center coordinates of the spherical surface cannot be known with high accuracy and the difference from the design value is large, so that the surface shape cannot be evaluated based on the error shape, and the corrected portion in the processing cannot be specified.

[0005] Further, since the defect of the uneven surface is not a point but a surface shape and is continuous, the method of detecting and removing the point by calculation as in the latter conventional example of the above-mentioned circular cross section is not used. The error shape between the average spherical surface including the missing surface and the actual shape is calculated, and accurate surface shape evaluation cannot be performed.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a three-dimensional measuring method capable of accurately specifying a correction portion for a design value of an object having an uneven surface with respect to a design value. It is.

Another object of the present invention is to provide a three-dimensional measuring method capable of accurately measuring the shape of an object having an uneven surface.

[0008]

Means for Solving the Problems The above-mentioned problems are solved,
In order to achieve the object, a three-dimensional measurement method according to the present invention is a three-dimensional measurement method for measuring a deviation from a design value of a shape of a surface of an object to be measured having a spherical surface. A measuring step of measuring the X, Y, and Z coordinate values of the above, a first calculating step of approximating the center coordinates of the spherical surface from the X, Y, and Z coordinate values measured in the measuring step; Movement of moving the center of the spherical surface by the design value from the center coordinates obtained in the first calculation step so that the spherical surface by the designed value of the measured object is a position that overlaps the spherical surface that is the measured value of the measured object. A second calculating step of calculating a difference between the measured value of the object and the spherical surface based on the design value superimposed by the moving step, and the spherical surface based on the designed value superimposed by the moving step and the measured object Is a measurement of an object And a display step of displaying a third calculation step of calculating a superimpose ratio between the surface, the calculation results obtained in the first to third operation step.

Further, in the three-dimensional measuring method according to the present invention, the X and Y coordinate values of the approximate center coordinates of the spherical surface, which are the measured values of the measured object, are added to the spherical and spherical coordinates based on the design value of the measured object. While the X and Y coordinate values of the center coordinates are matched, the center coordinates of the sphere according to the design value are shifted in the Z direction, so that the sphere according to the design value is superimposed on the sphere that is the measurement value of the object to be measured. It is characterized by:

In the three-dimensional measuring method according to the present invention, the positional relationship between the spherical surface according to the design value of the object to be measured and the spherical surface which is the measured value of the object to be measured is changed to the spherical surface which is the measured value of the object to be measured. Is displayed as a two-dimensional section parallel to the Z-axis passing near the center of.

Further, in the three-dimensional measuring method according to the present invention, a superimposition ratio of the spherical surface as the measured value and the spherical surface as the measured value of the object to be measured is based on the designed value with reference to the spherical surface as the measured value. It is characterized in that the ratio of the Z coordinate value of the spherical surface in the plus direction, the ratio of the Z coordinate value of the spherical surface in the minus direction according to the design value, or the ratio of the numbers in the plus direction and the minus direction.

Further, the three-dimensional measuring method according to the present invention comprises:
In a three-dimensional measurement method for measuring the deviation from the design value of the shape of the surface of the measurement object having a spherical surface, the measurement step of measuring the X, Y, Z coordinate values of any area of the surface,
A first calculating step of calculating a first approximate spherical equation from the measured X, Y, and Z coordinate values; a Z coordinate value calculated from the first spherical approximate equation; and a Z coordinate measured in the measuring step A second calculation step of calculating an error shape that is a difference between the error shape and the three-dimensional display, a specifying step of specifying an unnecessary area from the three-dimensionally displayed error shape, and measuring the specified unnecessary area. A third calculation step of removing the X, Y, and Z coordinate value data measured in the step to calculate a second spherical approximation equation;
A fourth calculating step of calculating a difference between the Z coordinate value calculated from the second spherical approximation formula and the Z coordinate value measured before removing the unnecessary area and displaying the difference in three dimensions. It is characterized by.

Further, in the three-dimensional measuring method according to the present invention, the first approximate spherical equation is calculated by a low-precision method, and the second approximate spherical equation is calculated by a high-precision method. I have.

Further, in the three-dimensional measuring method according to the present invention, the first and second approximate spherical expressions are both calculated by a highly accurate method.

Further, in the three-dimensional measuring method according to the present invention, the unnecessary area is specified by marking on the image while checking the image displayed in the second calculation step. I have.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the three-dimensional measuring method according to the present invention will be described below with reference to the accompanying drawings.

(First Embodiment) FIG. 1 is a diagram showing a schematic configuration of a three-dimensional measuring apparatus according to a first embodiment.

In FIG. 1, a motor (not shown) finely drives the base 1 in X and Y directions.
A stage 2 and a Y stage 3 are mounted, and an object to be measured 4 which is a spherical lens is fixed on the Y stage 3. A non-contact probe 5 using a laser or the like for measuring the Z coordinate is installed below the measuring unit 6.
Is mounted so as to be movable up and down and fixed to a column 7 erected on the base 1. The drive motors (not shown) of the X stage 2 and the Y stage 3 are connected by a signal line 8 to a computer 10 that performs control calculations, and are driven by control signals from the computer 10. The measuring unit 6 is connected to a computer 10 by a signal line 9,
In accordance with a control signal from the computer 10, the laser beam emitted from the non-contact probe 5 is focused to detect coordinates, and the data is sent to the computer 10. The computer 10 reads a program from a built-in hard disk drive or the like (not shown) in accordance with a command input from the keyboard 12, performs control and calculation according to the program, and displays the result on the display unit 11.

Next, the operation of the present system configured as described above will be described.

FIG. 2 is a diagram showing a specific example of measurement, FIG. 3 is a diagram showing a relationship between measured data and design values, FIG. 4 is a diagram showing a specific example of measurement processing display, and FIG. 5 realizes the present system. Is a flowchart showing a procedure for performing the above.

First, the DUT 4 is fixed to the Y stage 3 by an appropriate method, and a command to move the X stage 2 and the Y stage 3 to the measurement start position from the keyboard 12 is given. By this command, the computer 10 is in the X stage 2
And a control signal is sent to the drive motor of the Y stage 3, and the drive motor receives the control signal and
The stage 3 is driven to the measurement start position.

The driving is performed by giving a command from the keyboard 12 until the laser beam emitted from the non-contact probe 5 reaches the measurement start position L0 of the DUT 4 as shown in FIG. The computer 10 moves the measuring unit 6 to the focusing position (Z direction) of the laser beam irradiated by the non-contact probe 5 via the signal line 9 by the command (S1).

Next, in accordance with the program and parameters given from the keyboard 12, the X stage 2 performs fine movement at a constant pitch, and starts measurement from the measurement start position L0. In the measurement, as shown in FIG. 2, the X stage 2 is driven from the measurement start position L0 to the measurement start position L1, and the measuring unit 6 focuses the laser light from the non-contact probe 5 at each point of the constant pitch. , The Z coordinate value is detected from the focusing movement amount. The Z coordinate value is sent to the computer 10 via the signal line 9. At this time, the computer 10 calculates the Z coordinate value and the amount of movement of the X stage 2 and the Y stage 3 moved from the measurement start position L0, and calculates the measured values (X1i, Y1i, Z1) at the measurement points.
i) is stored in a memory of the computer 10 not shown.

The measurement is performed from L0 to L1, and when L1 is reached, the Y stage 3 is moved to L2. After the movement, the X stage 2 is finely moved toward the L3 at the constant pitch, and the measured values at the respective points are stored in the memory in the same manner as described above (S2). In this way, the measurement is repeated until the entire surface of the DUT 4 is completed (S3). When the measurement is completed, data is sequentially taken out of the memory storing the measured values and an approximate calculation is performed.

This approximation calculation is for obtaining rough center coordinates of the object to be measured, and therefore it is desirable that the accuracy is not so high and the speed is high. For example, the spherical formula (X−
^{x0) 2 + (Y-y0} ) 2 + (Z-z0) 2 = R 2 by using the least squares method for deploy, 2x0X + 2y0Y + 2z0Z
^{+ (R 2 -x0 2 -y0 2} -z0 2) = make a normal equation Y = AX as X ² + Y ² + Z ² solved for x0, y0, z0, R. The solved x0, y0, z0 become the approximate center coordinates of the measured object (S4).

Next, the coordinate values of X1i and Y1i are sequentially substituted from the memory in which the measured values are stored into the design value spherical equation using the solved x0, y0, and z0 as the center coordinates of the design value to obtain the Z2i value. Are separately stored in a memory (S5).

Subsequently, the measured value Z1i and the corresponding Z2i from the design value equation are sequentially compared, and it is checked whether or not the spherical surface according to the designed value overlaps with the spherical surface of the measured value (S6). If not, the center coordinate of the design value is moved in the Z-axis direction, and the process is repeated so that the spherical surface according to the design value is superimposed on the spherical surface of the measured value (S6, S7).

FIG. 3 is an explanatory view for making the spherical surface according to the design value overlap the spherical surface of the measured value. For the sake of simplicity, it is assumed that the radius of curvature of the measured value is smaller than the designed value as the cross-sectional shape. explain.

In FIG. 3, reference numeral 20 denotes a cross section of an approximate spherical surface of the DUT 4 having a center Z coordinate Z0 and a radius of curvature R. Reference numeral 21 denotes a cross section of a spherical surface obtained from design values, the center Z coordinate of which is Z2 and a radius of curvature R2. In (a), the spherical surface 21 obtained from the design value is above the surface of the DUT 4 and does not overlap the measured value spherical surface. Then, the center coordinate Z2 of the spherical surface 21 is moved downward,
As shown in (b), the measured value is superimposed on the spherical surface. When the spherical surface 21 is located below the surface of the DUT 4, the reverse may be performed. Here, the case where the radius of curvature of the measured value is smaller than the design value has been described.

The difference (error shape) between the measured value at that time and the designed value is calculated for all the measured value data with reference to the point where the spherical surface obtained from the designed value is superimposed on the spherical surface of the measured value (S8). . Further, it is checked for all data whether the Z coordinate value of the design value corresponding to the Z coordinate value of the measured value is greater than the Z coordinate value of the measured value, and the number of values larger than the measured value and the number of values smaller than the measured value are determined. It is calculated as a ratio (S9).
In addition, as this ratio, the ratio of the number of values larger than the measured value to the whole, the ratio of the number of values smaller than the measured value to the whole, or the ratio of the number of values larger than the measured value and the number of values smaller than the measured value And so on. The obtained ratio is displayed on the monitor 11 together with the error shape. At this time, the measured value closest to the XZ coordinate plane passing through the center of the spherical surface of the measured value is superimposed on the design value there, and the YZ coordinate plane orthogonal to the XZ coordinate plane and passing through the center of the measured spherical surface is The near measured value and the design value there are superimposed and displayed (S10).

FIG. 4 is a diagram in which the error shape, the ratio, the measured value on the XZ coordinate plane and the design value are superimposed, and the diagram in which the measured value on the YZ coordinate plane is superimposed on the design value, respectively. , A display screen displayed on the monitor 11. Here, 25 is the error shape, 26 is the ratio, and 27 is the XZ
Reference numeral 28 denotes superposition on a coordinate plane, and reference numeral 28 denotes superposition on a YZ coordinate plane.

In FIG. 4, it is confirmed from the superposition 27 on the XZ coordinate plane and the superposition 28 on the YZ coordinate plane how much the design value is shifted from the measured value. The degree is confirmed by the ratio value 26. The relationship between the measured value and the design value is determined based on the error shape 25 at that time (S11). If the degree of overlap between the measured value and the design value is not sufficient, the spherical surface is further moved according to the design value (S12). For this movement, use the keys of the keyboard 12, for example, "→""←""↑""↓"
The movement is performed in up, down, left, and right directions, and the measurement is repeated until the degree of overlap between the measured value and the design value is good.

In step S4, the approximation calculation by the least squares method was performed. However, the approximation calculation with higher accuracy may be performed, and the approximation calculation other than that described in the present embodiment may be used. Of course.

Although the description has been given of the non-contact probe three-dimensional measuring device using laser light, a non-contact probe other than laser light can be used as long as the device can measure X, Y, and Z coordinates. An apparatus using a contact probe may be used.

The measurement was performed in the direction shown in FIG.
As long as the X, Y, and Z coordinate values can be obtained, the directionality of the measurement does not matter, and the measurement area may be partial or full as needed.

Although the XZ coordinate plane and the YZ coordinate plane which are orthogonal to each other are used to easily confirm the relationship between the design value and the measured value, the accuracy may be increased by further dividing the plane.

As described above, according to the above-described embodiment, the shape of the design value is superimposed on the measurement data with reference to the center coordinate of the design value based on the center coordinate of the approximate spherical surface from the measurement data. Since the cross-sectional shape is displayed, it is possible to recognize the superimposed relationship between the measurement data and the design value and the error shape, to easily specify the correction part of the measured object with respect to the design value, and to set the center coordinates of the design value. Since the movable part can be freely moved, it is possible to easily specify an efficient correction portion of the measured object with respect to the design value.

(Second Embodiment) In the second embodiment, the configuration of the apparatus is the same as that of the first embodiment shown in FIG. However, in the second embodiment, the mouse 13 connected to the computer 10 gives an instruction to indicate the removal range and the like on the shape of the DUT displayed on the display unit 11.

Next, the operation of the system thus configured according to the second embodiment will be described. 2 and 6 are diagrams showing specific examples of measurement, and FIG. 7 is a flowchart showing a procedure for realizing the present system.

First, the DUT 4 is fixed to the Y stage 3 by an appropriate method, and a command to move the X stage 2 and the Y stage 3 to the measurement start position is given from the keyboard 12. By this command, the computer 10 is in the X stage 2
And a control signal is sent to the drive motor of the Y stage 3, and the drive motor receives the control signal and
The stage 3 is driven to the measurement start position.

Driving is performed by giving a command from the keyboard 12 until the laser beam emitted from the non-contact probe 5 reaches the measurement start position L0 of the DUT 4 as shown in FIG. The computer 10 moves the measuring unit 6 to the focusing position (Z direction) of the laser beam irradiated by the non-contact probe 5 via the signal line 9 according to the command (S31).

Next, according to the program and parameters given from the keyboard 12, the X stage 2 performs fine movement at a constant pitch, and starts measurement from the measurement start position L0. In the measurement, as shown in FIG. 2, the X stage 2 is driven from the measurement start position L0 to the measurement start position L1, and the measuring unit 6 focuses the laser light from the non-contact probe 5 at each point of the constant pitch. , The Z coordinate value is detected from the focusing movement amount. The Z coordinate value is sent to the computer 10 via the signal line 9. At this point, the computer 10 calculates the Z coordinate value and the amount of movement of the X stage 2 and the Y stage 3 moved from the measurement start position L0, and displays them as the measured values (X, Y, Z) at the measurement points. Is stored in the memory of the computer 10 which is not in use.

The measurement is performed from L0 to L1, and when L1 is reached, the Y stage 3 is moved to L2. After the movement, the X stage is finely moved toward the L3 at the constant pitch, and the measured value at each point is stored in the memory in the same manner as described above (S32). In this way, the measurement is repeated until the entire surface of the DUT 4 is completed (S33). When the measurement is completed, data is sequentially taken out of the memory storing the measured values and an approximate calculation is performed.

This approximation calculation is intended to make unnecessary uneven surfaces noticeable and easy to specify, and therefore it is desirable that the accuracy is not so high and the speed is high. For example, a spherical formula ^{(X-x0) 2 + (} Y-y0) 2 + (Z-z0) 2 = R 2
The least squares method is used to expand the spherical equation, and 2x
0X + 2y0Y + 2z0Z + (R 2 -x0 2 -y0 2 -z0 2) =
By setting a normal equation Y = AX as X ² + Y ² + Z ² , x 0,
Solve for y0, z0, R. Solved x0, y0, z0, R
Is a constant of the spherical equation, and is set as an approximate spherical equation of the measured object (S
34).

Next, the Z value is obtained by substituting the X and Y coordinate values into the spherical equation from the memory storing the measured values.
The difference between the determined Z value and the Z coordinate value of the measured value is calculated and separately stored in a memory. This is performed for all data to obtain error data (S35). Computer 10
Displays the error shape as a three-dimensional shape on the display unit 11 using the error data and the X and Y coordinates (S3).
6).

The three-dimensional shape of the measurement data of the spherical lens such as the object to be measured in the present embodiment naturally has a spherical shape as shown in FIG. When this is not displayed three-dimensionally, the uneven surface of the object to be measured is extremely difficult to find due to the relationship of curvature. Therefore, in the present embodiment, the error shape is displayed as a three-dimensional shape. For example, when looking at a part 50 in FIG. 6A, as shown in FIG. Are scattered (S3
6).

In such an error shape display, the mouse 13 is used to mark unnecessary unnecessary uneven surfaces 51 to be removed.
To specify (S37). When the unnecessary uneven surface is specified for the entire surface, the specified coordinates (X, Y, Z) are removed from the measurement data and stored in the temporary memory Temp (S38).

Next, the spherical equation is calculated again using the data in Temp. The approximation method in this case requires accuracy and is not a simple least square method, but is performed using a high accuracy approximation method such as a hybrid method based on a combination of the Gauss-Newton method or the steepest descent method, and x0, y0, R are calculated. Calculate (S3
9).

Then, the Z value is calculated by substituting the X and Y coordinate values of the measured data into the approximate spherical equation calculated by the approximate calculation. The difference between the calculated Z value and the Z coordinate value of the corresponding measurement data is determined, and error shape calculation is performed for all data (S40). After the error shape calculation is completed, the display unit 1
1 (S41).

In the above step S4, the approximate calculation by the least squares method was performed.
It is needless to say that a high-precision approximation calculation such as 39) may be performed, and an approximation calculation other than that described in the present embodiment may be used.

Similarly, if the approximation calculation in (Step S39) is highly accurate, it goes without saying that an approximation calculation other than that of the present embodiment may be used.

Although the description has been given of the non-contact probe three-dimensional measuring device using laser light, a non-contact probe other than laser light can be used as long as the device can measure X, Y, and Z coordinates. An apparatus using a contact probe may be used.

The measurement was performed in the direction shown in FIG.
As long as the X, Y, and Z coordinate values can be obtained, the directionality of the measurement does not matter, and the measurement area may be partial or full as needed.

In this embodiment, the marks are described as circles as shown in FIG. 6. However, any shape or color may be used as long as the uneven surface can be specified.

As described above, according to the second embodiment, an approximate spherical surface is calculated from measured data of an object to be measured, and an error shape of the object to be measured is calculated and displayed based on a difference from the measured data. The three-dimensional coordinates of the unnecessary uneven surface are specified from the error shape, the specified three-dimensional coordinates are removed from the measurement data, an approximate spherical surface is calculated from the remaining measurement data, and the measured object is calculated based on a difference from the measurement data. By calculating and displaying the error shape of the object, even if the object to be measured has an uneven surface, the surface shape of the object to be measured can be evaluated with high accuracy against a surface close to the original spherical shape. be able to.

[0056]

As described above, according to the present invention,
It is possible to accurately specify a correction portion for the design value of the DUT having the uneven surface.

Further, it is possible to accurately measure the shape of the object having the uneven surface.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a schematic configuration of a three-dimensional measuring apparatus according to an embodiment.

FIG. 2 is a diagram showing directions measured by a three-dimensional measuring device.

FIG. 3 is a diagram for explaining the relationship between measured values and design values.

FIG. 4 is a diagram illustrating a display state of a measurement result.

FIG. 5 is a flowchart illustrating a measurement procedure according to the first embodiment.

FIG. 6 is a diagram for explaining an error shape measured in the second embodiment.

FIG. 7 is a flowchart illustrating a measurement procedure according to the second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base 2 X stage 3 Y stage 4 DUT 5 Non-contact probe 6 Measuring part 7 Prop 8, 9 Signal line 10 Computer 11 Display part 12 Keyboard 20 Approximate spherical surface 21 Design spherical surface 25 Error shape 26 Ratio 27 XZ coordinate shape 50 Measurement shape 51 Uneven surface 52 Mark for identifying uneven surface

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2F065 AA04 AA46 AA54 BB05 BB28 DD03 FF10 FF61 GG04 MM03 PP12 QQ17 QQ21 QQ24 QQ32 SS02 SS13 2F069 AA04 AA13 AA66 CC08 GG04 GG07 GG71 JJ19 MM24 MM34 MM34

Claims (8)

[Claims] 1. A three-dimensional measuring method for measuring a deviation of a shape of a surface of an object having a spherical surface from a design value, wherein the X, Y, and Z coordinate values of an arbitrary region of the surface are measured. And a first step of approximating the center coordinates of the spherical surface from the X, Y, and Z coordinate values measured in the measuring step.
And calculating the center of the spherical surface by the design value in the first arithmetic step so that the spherical surface by the designed value of the device to be measured is located at a position overlapping the spherical surface that is the measured value of the device to be measured. A moving step of moving from the center coordinates, a second calculating step of calculating a difference between a spherical surface based on the design value superimposed by the moving step and the measured value of the device under test, and a design superimposed by the moving step. A third calculating step of calculating a superimposition ratio of a spherical surface based on a value and a spherical surface which is a measured value of the object to be measured, and a displaying step of displaying calculation results obtained in the first to third calculating steps. A three-dimensional measuring method comprising: 2. The X, Y coordinate values of the center coordinates of the spherical surface according to the design values of the measured object coincide with the X, Y coordinate values of the approximate calculated center coordinates of the spherical surface, which are the measured values of the measured object. The spherical surface according to the design value is superimposed on a spherical surface that is a measured value of the object to be measured by shifting a center coordinate of the spherical surface according to the design value in the Z direction in a state where the spherical surface is designed. Three-dimensional measurement method. 3. A positional relationship between a spherical surface according to a design value of the object to be measured and a spherical surface which is a measured value of the object to be measured is parallel to a Z axis passing near the center of the spherical surface which is a measured value of the object to be measured. The three-dimensional measurement method according to claim 1, wherein the three-dimensional measurement is displayed as a two-dimensional cross section. 4. A superposition ratio of the spherical surface according to the design value and the spherical surface as the measured value of the device under test is such that the Z coordinate value of the spherical surface according to the designed value is in the plus direction with respect to the spherical surface as the measured value. The ratio, or a ratio in which the Z coordinate value of the spherical surface according to the design value is in the minus direction, or a ratio of the numbers in the plus direction and the minus direction.
3. The three-dimensional measurement method according to 1. 5. A three-dimensional measuring method for measuring a deviation from a design value of a shape of a surface of an object having a spherical surface from a design value, wherein the X, Y, and Z coordinate values of an arbitrary region on the surface are measured. A first calculating step of calculating a first approximate spherical equation from the measured X, Y, and Z coordinate values; and a Z coordinate value calculated from the first spherical approximate equation and measured in the measuring step. A second calculation step of calculating an error shape that is a difference from the calculated Z coordinate value and displaying the error shape three-dimensionally; a specifying step of specifying an unnecessary region from the error shape displayed three-dimensionally; X measured in the measurement step,
A third calculation step of calculating a second spherical approximation formula by removing from the Y and Z coordinate value data; and a Z coordinate value calculated from the second spherical approximation formula and the unnecessary region before removing the unnecessary region. A fourth calculation step of calculating a difference from the measured Z coordinate value and displaying the difference three-dimensionally. 6. The three-dimensional measurement according to claim 5, wherein the first approximate spherical equation is calculated by a low-precision method, and the second approximate spherical equation is calculated by a high-precision method. Method. 7. The method according to claim 5, wherein both the first and second approximate spherical expressions are calculated by a highly accurate method.
3. The three-dimensional measurement method according to 1. 8. The three-dimensional measurement according to claim 5, wherein the identification of the unnecessary area is performed by marking on the video while checking the video displayed in the second calculation step. Method.