JP2003121129A - Apparatus and method for measurement of shape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the error amount of a phase shift when the surface of a specimen is inspected. SOLUTION: A cylindrical specimen 1 is turned, moire fringes at a specific fringe order are shifted precisely by a desired phase, a measuring region is limited to a part near the fringe order, its shape is measured on the basis of phase-shifted moire fringe data obtained by a light receiving element 13 at a measuring head 6 in a stereolattice-type moire optical system in which at least three lines of light receiving elements with linearly integrated pixels are. installed, the runout on the surface of the cylindrical specimen 1 in the arrangement direction of the light receiving element 13 is measured by a distance sensor 7 during the measurement of the shape, and the positional relationship between the light receiving element 13 and the cylindrical specimen 1 is controlled so as to be always constant in the arrangement direction of the light receiving element 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shape measuring apparatus and a shape measuring method for detecting the surface shape of, for example, a cylindrical test object and defects such as scratches, bulges, undulations and dents.

[0002]

2. Description of the Related Art As a method of inspecting a cylindrical test object such as a photosensitive drum for defects, for example, JP-A-2-201142 and JP-A-4-169840 are disclosed. Japanese Patent Laid-Open No. 2-20
In the abnormality detecting method disclosed in Japanese Patent No. 1142, as shown in FIG. 15, a laser light beam 32 from a light source 31 is irradiated through a rotating polygon mirror 36 so as to scan the photosensitive drum 33 in the axial direction, The scanning light is reflected by the surface of the photosensitive layer of the drum 30, and the light reflected from the normal surface almost enters the photodetector 35, the intensity of the reflected light is detected, and the output of the photodetector 5 is subjected to a predetermined arithmetic processing. It is input to the department. When the detected value is abnormally lowered by the processing here, it is detected as an abnormal surface state. Further, in the circumferential surface flaw inspection method disclosed in JP-A-4-169840, as shown in FIG. 16, a slit light 42 is projected from a projector 41 equipped with a halogen light source or the like toward a photosensitive drum 43. The scattered light scattered by the surface defect of the photoconductor drum 43 is condensed by the lens 44 and received by the line sensor 45, and the abnormality is detected by the scattered light due to the defect.

[0003]

Problems such as pinholes, dents, scratches, inclusion of air bubbles, cracks, dust, and other defects on the photoconductor, unevenness in the film thickness of the photosensitive layer, liquid sagging, and scratches on the support are considered. A wide variety of defects can occur. In the case of using the optical inspection device as described above, a defect having a large rate of change in surface irregularities, such as a defect caused by a pinhole, a dent, a scratch, dust, or the like, can be accurately detected. There is a problem in detection accuracy for a defect having a small rate of change in unevenness such as thickness unevenness or a defect having no change in unevenness on the surface of the photoconductor such as a scratch on the support.

On the other hand, one of the three-dimensional measurement methods is the moire method. The Moire method includes a physical lattice type and a lattice projection type, which are widely used in various fields. As shown in FIG. 17, the lattice projection type moire method is such that small lattices G1 and G2 are arranged for projection and observation, respectively, and G1 is projected onto an object by a lens L1 and deformed according to the object shape. This grid line is imaged on another grid G2 through the lens L2 so that the fringe contour line is generated at a predetermined distance from the reference plane. In the real lattice type moire method, as shown in FIG. 18, one lattice G is installed on the reference plane, and as shown in FIG. 19, a point light source S1 is placed at the position of the lens L1 and at the position of the lens L2. Observation eye e
, The shadow of the light source S1 of the grating G is cast on the object,
This is a method of forming a shadow of the lattice G deformed according to the shape of the object and observing the shadow through the lattice G to observe moire fringes generated by the lattice G and the shadow of the deformed lattice.

A more detailed description will be given by taking the real lattice type moire method as an example. As shown in FIG. 19, the gratings G1 and G1 are arranged on the same plane between the light source S1 and the observation point S2 and the object O.
2, the distance between the light source S1 and the observation point S2 is d, and the light source S is
1 and the distance from the observation point S2 to the grids G1, G1 is L,
The distance from the grids G1, G2 to the object O is h, and the grids G1,
G2 has a pitch s, but the gratings G1 and G2 are displaced from each other by ε in the plane (2πε / s in terms of the phase of the grating pitch), which can be expressed by the following equation (1). cos (2π / s) · [{dh−ε (h + L)} / (h + L)] (1) The moire fringes (contour lines) formed are based on the lattice plane (0
The second order has the orders that are sequentially counted as the first order and the second order with increasing distance from the lattice plane. Therefore, it is obtained by setting the moire fringe of the fringe order N as cos2πN. As a result, the Nth-order moiré contour line is formed at the position indicated by the following equation (2), which is separated from the reference surface by h _{N. h N = {(Ns + ε} ) L} / (d-Ns-ε) (2) which do not contain the coordinate x of the position, and has a unique value determined by the fringe order N. That is, it indicates that contour lines are formed.

The solid grid type moire method shown in FIG. 20 corresponds to one in which the gratings G1 and G2 shown in FIG. 19 are made into one continuous grating G, and ε = 0. From the equation (2), the following equation (3) is established. h _N = (NsL) / (d−Ns) (3) However, although it is called a contour line, the interval Δh _N = h _{N + 1} −h
_N is not constant and varies depending on the order N.

Conventionally, the three-dimensional shape measuring method based on the moire method can intuitively grasp an object, but (1) it is difficult to judge unevenness, and (2) it is not suitable for highly sensitive three-dimensional measurement ( At present, the distance between contours of moire fringes is limited to about 10 μm), and (3) the visibility of moire fringes is not uniform for each fringe, which makes it difficult to handle moire images as image processing targets. . This problem,
In the case of the grid projection type, since two grids are used,
By moving one of them to shift the fringe scanning, that is, the phase of the moire fringes, it is possible to equivalently divide the contour line finely and to determine the unevenness of the target and improve the measurement sensitivity.

The principle of this phase shift method will be described. As shown in FIG. 21, the phase-modulated fringe image can be represented by the following equation, where the bias is a, the amplitude is b, the operable phase is θ, and the phase value corresponding to the height is Φ. I = I (θ) = a (x, y) + b (x, y) cos {Φ (x, y) +
θ} What we want to find here is the phase Φ at each point (x, y).
(X, y). Since the bias a and the amplitude b are unknown components that change due to the reflectance and dirt of the surface, three fringe images represented by the following equations are generated by changing the phase θ to 0, π / 2, π. I = I (0) = a (x, y) + b (x, y) cos {Φ (x, y) +
θ} I = I (π / 2) = a (x, y) + b (x, y) cos {Φ (x,
y) + θ} I = I (π) = a (x, y) + b (x, y) cos {Φ (x, y) +
θ} Then, if the phase Φ (x, y) is calculated by the following equation (4), the reflectance and the dirt component can be removed to obtain the phase Φ (x, y) at each point. Φ (x, y) = tan ⁻¹ {(I3-I2) / (I1-I2)} + π / 4 (4)

However, in the case of the real lattice type, since the number of the lattice G is one, even if the phase shift such as the lattice projection type moire method is performed, the phases of the fringe contours of all orders are made uniform. It cannot be changed. For such a problem, for example, in the high-sensitivity three-dimensional measurement method shown in Japanese Patent No. 2887517, the vertical movement of the lattice plane and the horizontal movement of the light source or the observation point are performed at the same time, so that the moire fringes of each order are formed. Since the fringe phase can be shifted with respect to the measurement target in a state where the phases of the fringes of each order are almost the same without causing a large change in the phase, it is necessary to process from multiple fringe images based on the principle of the phase shift method. This makes it possible to increase the density of measurement points due to moire fringes on the object to be measured, and to physically divide about 1/40 to 1/100 per cycle of moire fringes. It is possible to determine the unevenness of the surface, which was considered difficult, and improve the measurement sensitivity.

However, in the case where the entire surface of a cylindrical test object or the like is measured by applying the phase shift method in this manner, grating movement and imaging of moire fringes are performed in order to shift the phase of the test object by rotating the test object three times or more. Must be repeated and it takes time to measure. Further, since it is necessary to move the grating in a plurality of directions (parallel and rotational), there is a problem that the device configuration becomes complicated.

The surface shape measuring device disclosed in Japanese Unexamined Patent Publication No. 7-332956 and the document "Physical lattice type moire method by phase shift" (Proceedings of the 1991 Precision Engineering Society Autumn Meeting, Academic Lecture Meeting), "Liquid Crystal Glass Flatness measurement ”(O plus E 19
(September 1996), the parallel light is applied to eliminate the difference in the fringe spacing due to the fringe order, so all the fringes are shifted in phase. Furthermore, these methods allow the phase shift only by the lattice motion.

However, when the entire surface of a cylindrical test object or the like is measured, it is necessary to repeat the operation of moving the grating and imaging in order to obtain a phase-shifted image, and the test object must be rotated three times or more. Cause an increase. Further, in the surface shape measuring method shown in JP-A-10-54711,
The phase is shifted by changing the height of the test object. Even in this case, it is necessary to repeat the movement and the imaging of the object to be inspected a plurality of times, which causes an increase in measurement time. In addition, a clear method for quantifying the uneven shape is not sufficiently explained.

The present invention solves the above-mentioned problems, and applies to a cylindrical test object such as a roller component or a flat test object such as a liquid crystal, and applies the phase shift method to the real lattice type moire method.
By obtaining a phase-shifted image by one series of imaging once, shape measurement is performed at high speed, and the surface of the object is inspected from the quantitative shape data, and the amount of phase shift error is reduced. An object of the present invention is to provide a shape measuring device and a shape measuring method that can perform the above.

[0014]

SUMMARY OF THE INVENTION A shape measuring apparatus according to the present invention is a physical lattice type moire optical system provided with a sensor having at least 3 lines of light receiving elements in which pixels are linearly integrated, and an object to be inspected. A holding and rotating mechanism for holding and rotating the object, and a rotational shake measuring means for measuring the rotational shake of the surface of the object to be measured in the direction of arrangement of the light receiving elements, and rotating the object to be measured, and moire fringes of a specific stripe order. Is accurately shifted by a desired phase, the measurement area is limited to the vicinity of the fringe order, shape measurement is performed from the phase-shifted moire fringe data obtained by the above sensor, and the rotational shake measuring means measures the shape of the light receiving element during the shape measurement. It is characterized in that the rotational shake of the surface of the object to be inspected in the arrangement direction is measured, and the result is controlled so that the positional relationship between the sensor and the object to be inspected is always constant in the arrangement direction of the light receiving elements.

A distance sensor may be used as the rotation shake measuring means. Further, as a rotational shake measuring means, a line light source and an area sensor are provided, and the rotational shake of the surface of the test object in the direction of arrangement of the light receiving elements is measured by detecting the apex position of the light receiving element of the test object. Is also good.

Further, the position of the light receiving element or the position of the test object is moved according to the measurement result of the rotational shake measuring means so that the positional relationship between the sensor and the test object is always constant in the arrangement direction of the light receiving elements. Control.

Furthermore, an area sensor having a large number of pixel rows is used as a sensor, and the rotational shake measuring means measures the rotational shake of the surface of the object to be measured in the direction in which the light receiving elements are arranged, so that a phase shift error does not occur. Image data in the area sensor may be selected.

Further, the rotational shake measuring means measures the rotational shake of the surface of the object to be measured in the direction in which the light receiving elements are arranged, the phase shift error amount is calculated from the result, and the shape data obtained by the area sensor is used as the phase shift error. It is good to correct using the amount.

In the shape measuring method according to the present invention, the object is rotated, the moire fringes of a specific fringe order are accurately shifted by a desired phase, and the measurement area is limited to the vicinity of the fringe order.
Shape measurement is performed from phase-shifted moire fringe data obtained by a sensor of a real lattice type moire optical system provided with a sensor having at least three lines of light-receiving elements in which pixels are linearly integrated, and the light-receiving element during shape measurement. The rotational shake of the surface of the object to be inspected in the arrangement direction of is measured, and from the result, the positional relationship between the sensor and the object to be inspected is controlled so as to be constant in the arrangement direction of the light receiving elements.

An area sensor having a large number of lines of pixels is used as the sensor, the rotational shake of the surface of the object to be measured in the direction of arrangement of the light receiving elements is measured, and image data in the area sensor is stored so that a phase shift error does not occur. Is selected.

Further, the rotational shake of the surface of the object to be measured in the direction of arrangement of the light receiving elements is measured, the phase shift error amount is calculated from the result, and the shape data obtained by the area sensor is corrected using the phase shift error amount. Good to do.

[0022]

1 is a perspective view showing the configuration of a shape measuring apparatus according to the present invention. As shown in the figure, the shape measuring device 2 for detecting the shape and defects of the cylindrical test object 1 includes a gripping jig 3 for fixing the cylindrical test object 1, a rotary motor 4 for rotating the gripping jig 3, It has a measuring head 6 and a distance sensor 7 provided on the automatic stage 5. The gripping jig 3 has, for example, a three-claw chuck, and centers and fixes the cylindrical test object 1. The automatic stage 5 is provided on the x-direction automatic stage 8 and the x-direction automatic stage 8 which moves in the x-direction which is the axial direction of the cylindrical object 1, and the z-direction which is the x-direction and the optical axis direction of the light receiving element 11. There is a y-direction automatic stage 9 that moves in the y-direction orthogonal to the direction, and the x-direction automatic stage 8 moves the measuring head 6 in the axial direction of the cylindrical test object 1,
The measuring head 6 is moved in the y direction by the direction moving stage 9. Then, the cylindrical test object 1 is fixed by the gripping jig 3, and the measuring head 6 is moved in the axial direction of the cylindrical test object 1 while rotating the gripping jig 3 by the rotation motor 4, so that the cylindrical test object 1 is moved. 1. Measure the entire surface of 1.

As shown in the perspective view of FIG. 2, the measuring head 6 includes a light source 10, a grid pattern 11 provided on the cylindrical object 1 side of the light source 10, and a cylindrical pattern with respect to the grid pattern 11. A lens 12 provided on the side opposite to the inspection object 1 at the same distance as the light source 10 with respect to the grid pattern 11,
The light receiving element 13 is provided on the side opposite to the lattice pattern 11 with respect to the lens 12. In the light receiving element 13, pixels are integrated in a line shape of at least 3 lines. Here, the case of three lines will be described. Each line of the light receiving element 13 is, as shown in FIG. 3, a row A, a row B, and a row C,
The positional relationship among the light receiving element 13, the lattice pattern 11 and the cylindrical test object 1 is obtained by utilizing the fact that the test object 1 is cylindrical as shown in FIGS. I will change the height corresponding to the field of view. The pixel rows A, B, and C of the light receiving element 13 are arranged in the y direction. Here, the rotation speed of the cylindrical object 1, the scanning cycle of the light receiving element 13, the imaging magnification, the pixel array A, and the pixel array A, so that a desired step amount is given.
Adjust the distance between B and C.

When the cylindrical test object 1 is imaged by the pixel rows A, B, and C of the light receiving element 13, first, as shown in FIG. 4, the cylindrical test object 1 in the A row at time t ₁ . Area 3
(Step 0 surface), row 2 in area 2 (Step 1 surface)
Is imaged in the region 1 (step 2 surface) in the C column. Next, at time t ₂ , the area 4 (step 0 surface) in the column A is set to B
Region 3 (step 1 surface) is imaged in a row, and region 2 (step 2 surface) is imaged in a column C. Further, at time t ₃ , the area 5 (step 0 surface) is in the row A, and the area 4 (step 1 surface) is in the row B.
Area 3 (step 2 surface) is imaged in the C column. By repeating this, the detection data by the pixel rows A, B, and C for each time is obtained in the image memory as shown in FIG. Therefore, the data of column A at time t ₁ and time t ₂
The data of the B column of and the data of the C column at time t ₃ are shown in (4) below.
Formula Φ (x, y) = tan ⁻¹ {(I3-I2) / (I1-I
2)} + π / 4 (4) The shape of the region 3 can be measured. Based on this quantitative shape data, defect inspection such as undulations and dents generated on the surface of the cylindrical object 1 and flatness inspection are performed.

Strictly speaking, since the fringe spacing differs depending on the fringe order, the step amount varies depending on the fringe order to be measured, and a measurement error occurs, but the distance L from the lens 12 to the lattice pattern 11 is 200 mm, and the distance between the light source 10 and the lens 12 is large. Distance 70mm,
The lattice spacing of the lattice pattern 11 is 83.3 μm (12 / m
m), the moire contour fringes h _N are as shown in FIG. 6 by the following equation (3) h _N = (NsL) / (d−Ns) (3).
Here, assuming that the reference height of the cylindrical test object 1 is set to the position of the stripe order n = 3 and the measurement range is set to a range of about 480 μm with n = 2 to 4, Δh ₂ = 239.423 μm, Δh ₃ = 239.995
The difference in μm is as small as 0.572 μm, which is a level that does not pose a problem in measuring undulations or dents whose height difference is about several μm.

In the above method, the positional relationship between the cylindrical test object 1 and the pixel rows A, B and C of the light receiving element 13 becomes very important. That is, when the cylindrical test object 1 moves in the y direction due to the influence of rotational shake, it deviates from the desired step amount, and thus an error occurs in the shape data. On the other hand, when the cylindrical test object 1 is shaken in the optical axis direction z of the light receiving element 13, the shape data including the rotational shake is obtained because the step amount does not change, but one round of the cylindrical test object 1 is obtained. Can be removed by frequency processing such as removing the frequency component corresponding to. That is, in the shape measurement of the cylindrical test object 1 using the phase shift moire method, the positional relationship between the measurement head 6 and the cylindrical test object 1 is controlled to be constant in the y direction, and the phase shift error amount is controlled. It is necessary to reduce.

Therefore, as shown in FIG. 7, the distance sensor 7 measures the rotational shake amount of the cylindrical object 1 in the y direction, and based on the measurement result, the pixel rows A, B, and C of the light receiving element 13 are detected. While the positional relationship of the cylindrical test object 1 is kept constant in the y direction, the cylindrical test object 1 is rotated and images are taken. As shown in FIG. 8, instead of the distance sensor 7, an outer diameter measuring machine is used from the light projecting section 14 and the light receiving section 15, or the ridgeline of the cylindrical object 1 is imaged by another camera. The rotational shake of the cylindrical test object 1 may be measured by calculating the position of the cylindrical test object 1.

In order to keep the positional relationship between the pixel arrays A, B and C of the light receiving element 13 and the cylindrical object 1 constant in the y direction, as shown in FIG. 9, based on the measurement result of the distance sensor 7, The y-direction automatic stage 15 controls the position of the light-receiving element 13 so that the positional relationship between the pixel rows A, B, and C of the light-receiving element 13 and the cylindrical test object 1 is constant in the y-direction. Here, the gripping jig 3 that rotates while holding the cylindrical test object 1 and the rotation motor 4 are provided on an automatic stage that is movable in the y direction, and based on the measurement result of the distance sensor 7, the light receiving element 1
The positional relationship between the three pixel rows A, B, and C and the cylindrical test object 1 is y.
You may make it constant in a direction.

Further, instead of the distance sensor 12 which measures the rotational shake amount of the cylindrical test object 1 in the y direction, the apex position 16 in the z direction of the cylindrical test object 1 is measured as shown in FIG. Then, based on the measurement result, the pixel row A of the light receiving element 13,
The positional relationship between B and C and the cylindrical test object 1 may be constant in the y direction. As a method for detecting the apex position 16 of the cylindrical test object 1, for example, a light cutting method may be used as shown in FIG. This light cutting method is shown in FIG.
As shown in FIG. 1, light is projected from the line light source 17 onto the cylindrical test object 1 and observed through the lens 19 by the area sensor 18 having pixel rows in the x direction and the y direction. At this time, in the area sensor 18, as shown in FIG. 12, an arc 20 is observed according to the shape of the cylindrical test object 1. The apex position 16 of the arc 20 is detected by image processing,
The y-direction position is measured. Based on this vertex position 16, the positional relationship between the pixel rows A, B, C of the light receiving element 13 and the cylindrical test object 1 is kept constant in the y direction.

Further, according to the measurement result of the distance sensor 7, the measuring head 6 or the cylindrical test object 1 is moved in the y direction, and the pixel rows A, B, C of the light receiving element 11 and the cylindrical test object 1 are moved. Instead of keeping the positional relationship constant in the y direction,
As shown in FIG. 13, an area sensor 21 having a pixel line of many lines may be used as the light receiving element 13. It is assumed that the area sensor 21 has a pixel line of 100 lines, for example, and the image data for obtaining a desired step amount corresponds to the 10th line, the 15th line, and the 20th line. In this case, while the cylindrical test object 1 is being rotated, the area sensor 21 picks up an image in the first frame, the second frame, the third frame, ... And stores the image data. Further, the rotational shake of the cylindrical object 1 in the y direction is also measured and stored by the distance sensor 7. If the rotational shake measurement value at the time of capturing the first frame is “0”, the image data of the 10th line, the 15th line, and the 20th line is selected. The shape data may be calculated by selecting the image data such as the 15th line, the 20th line, and the 25th line so that the amount can be obtained.

Further, as shown in FIG. 14, assuming that the actual shape data is x and the measured value is y, there is a relation of y = x when there is no phase shift error. However, when the shape data is calculated using the equation (4) despite the presence of the phase shift error, the shape data also has an error, which results in a relation of y = ax + b. Therefore, y of the cylindrical object 1 is measured by the distance sensor 7.
The rotational shake in the direction is measured, and the shift error amount is calculated from the measured value. If this shift error amount is known, y =
The unknowns a and b of ax + b are known, and it is possible to correct to a value with no phase shift error.

[0032]

As described above, according to the present invention, the object is rotated, the moire fringes of a specific fringe order are accurately shifted by a desired phase, and the measurement area is limited to the vicinity of the fringe order. At least three light-receiving elements that are linearly integrated
The shape is measured from the phase-shifted moire fringe data obtained by the sensor of the real lattice type moire optical system provided with the sensor having the line, and the surface of the object to be inspected in the alignment direction of the light receiving elements by the rotational shake measuring means during the shape measurement. It is possible to reduce the phase shift error when measuring the shape by measuring the rotational shake of the sensor and controlling it so that the positional relationship between the sensor and the test object is always constant in the direction in which the light receiving elements are arranged. , Surface shape of the object to be inspected, scratches and bulges,
Defects such as undulations and dents can be detected accurately.

Further, a distance sensor is used as the rotational shake measuring means, or a line light source and an area sensor are provided, and the apex position on the light receiving element side of the test object is detected to detect the surface of the test object in the arrangement direction of the light receiving elements. By measuring the rotational shake of the object, the rotational shake of the surface of the test object can be accurately measured.

Further, the position of the light receiving element or the position of the object to be inspected is moved according to the measurement result of the rotational shake measuring means so that the positional relationship between the sensor and the object to be inspected is always constant in the arrangement direction of the light receiving elements. By controlling, the relative position of the sensor and the test object can be automatically adjusted with a simple configuration.

Further, an area sensor having a large number of lines of pixels is used as a sensor, and the rotational shake measuring means measures the rotational shake of the surface of the object to be measured in the direction in which the light receiving elements are arranged, so that a phase shift error does not occur. By selecting the image data in the area sensor, it is possible to accurately reduce the phase shift error when measuring the shape.

Further, the rotational shake of the surface of the object to be measured in the direction of arrangement of the light receiving elements is measured, the phase shift error amount is calculated from the result, and the shape data obtained by the area sensor is corrected using the phase shift error amount. By doing so, the shape measurement error due to the phase shift error can be reduced.

[Brief description of drawings]

FIG. 1 is a perspective view showing a configuration of a shape measuring apparatus of the present invention.

FIG. 2 is a perspective view showing a configuration of a measuring head.

FIG. 3 is a layout diagram showing a positional relationship between a light receiving element, a lattice pattern, and a cylindrical test object.

FIG. 4 is an arrangement diagram showing a measurement region of a pixel row of a light receiving element.

FIG. 5 is an explanatory diagram showing measurement data of a pixel array of a light receiving element for each time.

FIG. 6 is an explanatory diagram showing measurement data of a pixel row of a light receiving element.

FIG. 7 is a layout view of a distance sensor for a cylindrical test object.

FIG. 8 is a configuration diagram of an outer diameter measuring device that measures rotational runout of a surface of a cylindrical test object.

FIG. 9 is an arrangement diagram showing a moving direction of a light receiving element when rotational shake of the surface of a cylindrical test object occurs.

FIG. 10 is an arrangement diagram showing a positional arrangement relationship between a vertex position of a cylindrical test object and a light receiving element.

FIG. 11 is a configuration diagram of a measuring device that measures the apex of a cylindrical test object by a light section method.

FIG. 12 is an explanatory diagram showing measured vertex positions.

FIG. 13 is a layout diagram showing a positional relationship between a light receiving element having an area sensor, a lattice pattern, and a cylindrical test object.

FIG. 14 is a change characteristic diagram of measured values depending on the presence or absence of a phase shift error.

FIG. 15 is a layout diagram showing a conventional configuration.

FIG. 16 is a layout diagram showing the configuration of another conventional example.

FIG. 17 is an explanatory diagram of a lattice projection type moire method.

FIG. 18 is an explanatory diagram of a real lattice type moire method.

FIG. 19 is a layout diagram of a light source, an observation point, a grid, and an object by the moire method.

FIG. 20 is a layout diagram of a light source, an observation point, a lattice, and an object of a real lattice type moire method.

FIG. 21 is a light intensity characteristic diagram of a phase-modulated fringe image.

[Explanation of reference numerals] 1; cylindrical test object, 2; shape measuring device, 3; gripping jig,
4; rotary motor, 5; motorized stage, 6; measuring head,
7; distance sensor, 8; x-direction automatic stage, 9; y-direction automatic stage, 10; light source, 11; lattice pattern, 1
2; lens, 13; light receiving element.

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Claims (9)

[Claims] 1. A physical lattice type moire optical system provided with a sensor having at least three lines of light-receiving elements in which pixels are linearly integrated, a gripping rotation mechanism for holding and rotating an object, and a light-receiving element. It has a rotation shake measuring means for measuring the rotation shake of the surface of the object to be measured in the arrangement direction of, and rotates the object to accurately shift the moire fringes of a specific stripe order by a desired phase, and The shape is measured from the phase-shifted Moire fringe data obtained by the sensor, limited to the vicinity of the fringe order, and the rotational shake of the surface of the object to be measured in the alignment direction of the light receiving elements is measured by the rotational shake measuring means during the shape measurement. From the result, the shape measuring apparatus is controlled so that the positional relationship between the sensor and the object to be inspected is always constant in the arrangement direction of the light receiving elements. 2. The shape measuring device according to claim 1, wherein the rotation shake measuring means is a distance sensor. 3. The rotational shake measuring means has a line light source and an area sensor, detects the apex position on the light receiving element side of the object to be measured, and measures the rotational shake of the surface of the object in the direction of arrangement of the light receiving elements. The shape measuring device according to claim 1. 4. The position of the light receiving element or the position of the test object is moved according to the measurement result of the rotational shake measuring means so that the positional relationship between the sensor and the test object is always constant in the direction in which the light receiving elements are arranged. The shape measuring apparatus according to claim 1, wherein 5. An area sensor having a large number of lines of pixels is used as the sensor, and the rotational shake measuring means measures the rotational shake of the surface of the object to be measured in the direction in which the light receiving elements are arranged so that a phase shift error does not occur. 5. The image data in the area sensor is selected as the image data.
The shape measuring device according to any one of 1. 6. The rotational shake measuring means measures the rotational shake of the surface of the test object in the arrangement direction of the light receiving elements, calculates the phase shift error amount from the result, and phase-shifts the shape data obtained by the area sensor. The shape measuring apparatus according to claim 5, wherein the shape measuring apparatus corrects using an error amount. 7. A light receiving element in which pixels are linearly integrated by rotating a test object to accurately shift a moire fringe of a specific fringe order by a desired phase and limiting a measurement region to the vicinity of the fringe order. Shape measurement is performed from phase-shifted moire fringe data obtained by a sensor of a real lattice type moire optical system provided with a sensor having at least 3 lines, and rotation of the surface of the test object in the alignment direction of the light receiving elements during the shape measurement. A shape measuring method characterized by measuring a shake and controlling from the result so that the positional relationship between the sensor and the object to be measured is always constant in the direction in which the light receiving elements are arranged. 8. An area sensor having a large number of lines of pixels is used as the sensor, the rotational shake of the surface of the object to be measured in the direction in which the light receiving elements are arranged is measured, and an area sensor is provided in the area sensor to prevent a phase shift error. The shape measuring method according to claim 7, wherein image data is selected. 9. The rotational shake of the surface of the object to be measured in the direction in which the light receiving elements are arranged is measured, the phase shift error amount is calculated from the result, and the shape data obtained by the area sensor is calculated using the phase shift error amount. The shape measuring method according to claim 8, wherein the shape is corrected.