JP2003322516A - Shape measuring method and shape measuring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the phase-shift error quantity when measuring the shape of a cylindrical article to be measured such as a roller part by applying a phase shift method. <P>SOLUTION: The cylindrical article to 1 is rotated, and moire fringes having a specific fringe order are shifted accurately as much as a desired phase, and a measuring region is limited near the fringe order, and the shape is measured from phase-shifted moire fringe data acquired by a two-dimensional area sensor 13. At that time, a spot image 24 of spot light 23 is projected onto an area where the moire fringes of the same image as the phase-shifted moire fringe data are not generated, and the position change of the cylindrical article to be measured 1 is detected from the position of the spot image 24, and the position relation between the two-dimensional area sensor 13 and the cylindrical article to be measured 1 is fixed. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shape measuring method and a shape measuring apparatus for detecting the surface shape of a cylindrical test object or the like 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 detection method disclosed in Japanese Patent No. 1142, as shown in FIG. 17, a laser light beam 32 from a light source 31 is irradiated via a rotary polygon mirror 36 so as to scan in an axial direction of a photosensitive drum 33, 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 Japanese Patent Laid-Open No. 4-169840, as shown in FIG. 18, 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. 19, 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 physical lattice type moire method, as shown in FIG. 20, one lattice G is installed on the reference surface, and as shown in FIG. 21, the point light source S1 is placed at the position of the lens L1 and the observation is made at the position of the lens L2. With the eye e placed, a shadow of the light source S1 of the grid G is cast on the object to form a shadow of the grid G deformed according to the shape of the object. This shadow is observed through the grid G, and the shadow of the grid G and the deformed grid is observed. This is a method of observing moire fringes caused by and.

The actual lattice type moire method will be described in more detail. As shown in FIG. 21, the light source S1 and the observation point S
2 and the object O, the gratings G1 and G2 are arranged on the same plane, the distance between the light source S1 and the observation point S2 is d, the distance from the light source S1 and the observation point S2 to the gratings G1 and G1 is L, and the grating G is
1 and G2 is the distance from the object O to h, and the gratings G1 and G2 both have a pitch s, but the gratings G1 and G2 are offset from each other by ε in the plane (2π in terms of the phase of the grating pitch).
ε / s) 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 actual lattice type moire method shown in FIG. 22 corresponds to one in which the gratings G1 and G2 shown in FIG. 21 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 finely divide the contour line interval and determine the target unevenness and improve the measurement sensitivity.

The principle of this phase shift method will be described. As shown in FIG. 23, the phase-modulated fringe image can be expressed 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.

When the entire surface of a cylindrical test object or the like is measured by applying the phase shift method as described above, at least three test objects are tested.
Since it is necessary to repeat the movement of the grating and the imaging of the moire fringes in order to make the phase shift by rotating or more, it takes a long 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. In these methods, it is possible to shift the phase only by the lattice movement.

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, the phase shift method is applied to the real lattice type moire method, and it is performed once by one system image pickup apparatus. By obtaining a phase-shifted image by a series of image pickups, the shape measurement can be performed at high speed, the surface of the object to be inspected can be inspected from the quantitative shape data, and the movement amount error of the object can be measured. It is an object of the present invention to provide a shape measuring method and a shape measuring device that can be performed.

[0014]

A shape measuring method according to the present invention comprises rotating a test object to accurately shift a moire fringe of a specific fringe order by a desired phase, and setting a measurement region near the fringe order. For example, the shape is measured from the phase-shifted moire fringe data obtained by the two-dimensional area sensor, and the position of the object is measured from the same image as the phase-shifted moire fringe data during the shape measurement by a method different from the phase-shift moire method. It is characterized in that fluctuation detection is performed.

Pattern light having regularity is projected onto a region of the same image as the moiré fringe data phase-shifted during the shape measurement, in which moiré fringes are not generated, and the position or pattern shape is used to change the position of the test object. Detected or phase-shifted Moire fringe data The same image as the moiré fringes in the same image. The position variation is detected during the shape measurement by detecting the position variation of the object and image-processing the same image as the phase-shifted moire fringe data without using the position variation detection sensor.

It is also possible to detect the position variation of the object to be inspected from the moire fringe image which does not phase shift during the shape measurement.

Further, the phase shift calculation area used for the shape measurement is changed according to the position variation detection data of the object to be subjected to the phase shift calculation to reduce the phase shift error.

Further, the positional relationship between the measuring head and the test object is controlled to be constant according to the position variation of the test object to suppress the influence of the rotational shake and reduce the phase shift error.

The shape measuring apparatus according to the present invention has a measuring head having a body lattice type moire optical system having a two-dimensional area sensor, and a grip rotating mechanism for holding and rotating an object to be inspected. The object is rotated, the moire fringes of a specific fringe order are accurately shifted by a desired phase, the measurement area is limited to the vicinity of the fringe order, and the shape is measured from the phase-shifted moire fringe data obtained by the two-dimensional area sensor. The position variation of the object to be detected is detected from the same image as the moiré fringe data phase-shifted during shape measurement by a method different from the phase-shift moiré method.

[0020]

1 is a perspective view showing the configuration of a shape measuring apparatus according to the present invention. As shown in the figure, a shape measuring device 2 for detecting the shape and defects of a cylindrical test object 1 is, for example, a gripping jig for fixing the cylindrical test object 1 such as a photoconductor used for electrophotographic image formation. 3, a rotary motor 4 for rotating the holding jig 3, and a measuring head 6 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 has an x direction, which is an axial direction of the cylindrical test object 1,
It is movable in the y and z directions orthogonal to the x direction.
Then, the cylindrical test object 1 is fixed by the gripping jig 3, and the measuring head 6 is moved in the x direction, which is the axial direction of the cylindrical test object 1, while rotating the gripping jig 3 by the rotation motor 4. The entire surface of the test object 1 is measured.

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,
It has a two-dimensional area sensor 13 provided on the opposite side of the lens 12 from the grid pattern 11. The two-dimensional area sensor 13 includes a moire fringe image pickup area 131 for picking up a moire fringe projected from the light source 10 through the lattice pattern 11 on the cylindrical object 1, and a background image pickup area 132 for picking up an image of other portions. Have. The moire fringe image capturing area 131 captures moire fringes with at least an arbitrary 3-line pixel row.
Here, the case of three lines will be described. As shown in FIG. 3, each line of the moire fringe imaging area 131 is set to rows A, B, and C, and the positional relationship among the moire fringe imaging area 131, the lattice pattern 11, and the cylindrical object 1 is as shown in FIG. Also, as shown in FIG. 4, the height corresponding to the visual fields of the pixel rows A, B, and C is changed by utilizing the fact that the test object 1 has a cylindrical shape. The pixel rows A, B, C are arranged in the y direction. Here, the rotation speed of the cylindrical object 1, the scanning cycle of the two-dimensional area sensor 13, the imaging magnification, and the distance between the pixel rows A, B, and C are adjusted so that a desired step amount is given.

The pixel row A in the moire fringe image pickup area 131,
When imaging the cylindrical test object 1 with B and C, first, as shown in FIG.
As shown in the cylindrical test object in row A at time t ₁ 1
Area 3 (step 0 surface), area 2 (step 1 surface) in row B, and area 1 (step 2 surface) in row C are imaged. Next, at time _{t 2,} the area 4 in column A (step plane 0)
, Area 3 (step 1) in row B, area 2 in row C
(Step 2 surface) is imaged. Furthermore, at time t ₃ , A
Area 5 (step 0 surface) is imaged in the row, area 4 (step 1 surface) is imaged in the row B, and region 3 (step 2 surface) is imaged in the row C. By repeating this, the image shown in FIG.
As shown in, detection data by the pixel rows A, B, and C at each time is obtained. Therefore, the data of the column A at the time t ₁ , the data of the column B at the time t ₂ and the data of the column C at the time t ₃ are expressed by the following equation (4) Φ (x, y) = tan ⁻¹ {(I3-I2) The shape of the region 3 can be measured from / (I1-I2)} + π / 4 (4). 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 varies depending on the fringe order, the step amount varies depending on the fringe order to be measured, and a measurement error occurs. However, the distance L from the lens 12 to the grid 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 object 1 and the pixel rows A, B and C of the two-dimensional area sensor 13 becomes very important. That is, the cylindrical test object 1
When is moved in the y direction due to the influence of rotational runout, 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 two-dimensional area sensor 13, the step data does not change, and thus shape data including rotational shake is obtained. It can be removed by frequency processing such as removing the frequency component corresponding to one round. That is, in the shape measurement of the cylindrical test object 1 using the phase shift moire method, the positional relationship between the measuring head 6 and the cylindrical test object 1 is always y.
It is necessary to reduce the amount of phase shift error by controlling so as to be constant in the direction.

Therefore, as shown in FIG. 2, the shape information and the position information are obtained from the same image picked up by the two-dimensional area sensor 13 having the moire fringe image pickup region 131 and the background image pickup region 132 of the other portion. This two-dimensional area sensor 13
FIG. 7 shows a typical example of an image obtained by capturing the moire fringes projected on the cylindrical test object 1. The outer rectangle of the image 20 shown in FIG. 7 indicates the imaging area of the two-dimensional area sensor 13. In the central area 21 of this image 20, there is a striped image of the measured portion of the cylindrical test object 1, and the other solid areas are uniform because there is no reflected light because of the background portion where the measured portion does not exist. The image 22 is obtained. Here, as the cylindrical test object 1 rotates, y shown in FIG.
The displacement in the direction corresponds to the uniform distance dy of the image 22, and the displacement in the z direction corresponds to the distance wy of the central region 21 because the imaging magnification changes. Therefore, by obtaining the distance dy and the distance wy, the shift amount can be obtained by performing image processing on the same image 20 captured by the two-dimensional area sensor 13, and the shift amount and the surface shape can be simultaneously detected from the same image 20. be able to.

Considering that the region measured by the phase shift moire is near the central axis of the cylindrical object 1, (dy + wy) / 2 can be used as the displacement in the y direction. Further, the transmitted light from below the cylindrical object 1 may be incident on the two-dimensional area sensor 13 in order to obtain an image with a larger contrast.

By controlling the position of the measuring head 6 with the automatic stage 5 according to the amount of deviation detected in this way, the position of the measuring head 6 with respect to the cylindrical object 1 can be kept constant and the phase shift error can be maintained. Can be reduced. Further, by selecting the line used for the phase shift of the two-dimensional area sensor 13 according to the detected shift amount in the y direction, it is possible to perform accurate phase shift.

Further, when performing a highly accurate measurement, it is necessary to image the moire fringes at a high magnification, and it is difficult to capture the background portion as shown in FIG. Therefore, the measuring head 6
8, a spot light source 14 such as a laser pointer is provided, and the spot light 23 is projected from the spot light source 14 onto the surface of the cylindrical test object 1 as shown in FIG. The area sensor 13 is a moire fringe image pickup area 131.
The image of the moire fringe is picked up, and the spot image 24 is picked up by the spot light 23 in the background image pickup area 132. This 2
An image 20 taken by the dimensional area sensor 13 is shown in FIG. The position of the cylindrical object 1 can be detected from the position dy of the spot image 24 of this image 20 by the principle of triangulation. In this way, the displacement amount in the y direction can be detected without measuring the displacement amount in the y direction by the distance sensor using the outer shape of the cylindrical test object 1.

The spot light 23 projected on the cylindrical object 1 is not limited to one point, but may be a plurality of points. In addition, instead of the spot light 23, a shape such as a circle or a rectangle is projected as an image, the image is picked up by the two-dimensional area sensor 13, and the shape change, the area change, the center of gravity, or the like is used to detect the cylindrical shape. The inclination and position of the object 1 can also be detected.

Further, as shown in the schematic view of FIG. 11, at the end of the lattice of the two-dimensional area sensor 13 of the lattice pattern 11 on the observation point side, the end where the reflected light from the cylindrical object 1 does not pass again. There is a partial pattern portion 111, and moire fringes are not formed in this end portion pattern portion 111.
The lattice pattern 11 is captured by the dimensional area sensor 13 as it is, and an arc-shaped lattice pattern 25 is formed in the captured image 20, as shown in FIG. By obtaining the central axis of the cylindrical test object 1 from the arc-shaped lattice pattern 25, it is possible to detect the deviation amount due to the rotation of the arc-shaped test object 1.

Further, the resolution of the two-dimensional area sensor 13 is set with respect to the width of the lattice pattern 11 so that only the moire fringes are imaged without directly capturing the end pattern portion 111 of the lattice pattern 11 into the two-dimensional area sensor 13. When capturing an image under a condition that is not sufficiently fine, the arc-shaped lattice pattern 25 generated in the end pattern portion 111 is too fine to be observed. In such a case, as shown in FIG. 13A, only the end pattern portion 111 has a longer period, or as shown in FIG. 13B, a lattice pattern substrate such as glass on which the lattice pattern 11 is formed. The image 20 having the arc-shaped lattice pattern 25 can be obtained by forming the shift amount measurement pattern 113 on the end surface of 112 so that light does not pass therethrough.

Further, in order to perform the phase shift, it is necessary to acquire three pieces of image data at least at the same place. Therefore, the cylindrical test object 1 is imaged by using a normal moire method, and as shown in FIG. 14, three phase-shifted images 26a, 26b, and 26c for shape measurement are imaged and the cylindrical test object 1 is taken. From the images 27a to 27c obtained by obtaining the unevenness information of No. 1 and performing the phase shift processing for each column in the circumferential direction which is the vertical direction of the image from this unevenness information to obtain the most convex portion, and performing the linear approximation and performing the phase connection. The axis 28 of the cylindrical test object 1 may be detected. In this case, since the phase shift is not performed, the accuracy of the shape of the cylindrical test object 1 is inferior, but the position variation in the y direction can be detected from the line representing the axis 28. At this time, the concavo-convex data obtained from the moire method is used as the cylindrical test object 1
It is possible to detect a position with higher accuracy by performing fitting on the cylindrical shape. In addition, as shown in FIG. 14, by connecting the portions where phase skipping occurs,
The accuracy can be improved by performing fitting in a wider range in the circumferential direction, and the fitting process using only one cycle of the central portion can be omitted to shorten the calculation time by omitting the phase connecting process. Further, as shown in FIG. 15, the moire processing is performed only in the limited area 29 and the linear approximation is performed, whereby the processing amount for calculating the central axis position of the cylindrical object 1 can be reduced, The calculation cost can be reduced.

Further, as shown in FIG. 4, even in the case where the phase shift is performed by synchronizing with the cylindrical object 1 to be sequentially moved, the process of performing the shape measurement uses the phase shift from the data acquired at different times. Although the processing is performed, the image data used in the moire method for calculating the axial position of the cylindrical test object 1 can be obtained for each time using the image data of the same time. Further, in the case where the phase shift is performed by synchronizing with the surface of the test object that moves sequentially in this way, the phase shift is performed from the detected axial position of the cylindrical test object 1 as shown in FIG. By changing the line for performing the, it is possible to reduce the error in the position variation in the y direction due to the axis deviation. In FIG. 16, as the lines for phase shifting, lines with a constant width are shown above and below the most convex line of the shaft 28, but in reality, the lines are defined not as the top and bottom but as the relative position from the detected center. Therefore, the calculated axis is not always used as it is, and the accuracy of the accuracy can be improved by appropriately changing the interval between the lines for performing the phase shift when the diameter of the cylindrical test object 1 varies. Can be improved.

Further, by using the angle formed by the two-dimensional area sensor 13 obtained by linear approximation of the axis, the optical system consisting of the two-dimensional camera, the light source, and the grating pattern, and the axis direction of the object to be inspected are controlled to be constant. By accurately setting the line data to be shifted in parallel with the axial direction, it is possible to make the amount of phase shift, which is different at each measurement point due to rotation, constant.

Further, in one moiré fringe image without phase shift shown in FIG. 14, it was obtained by fitting the change in height of the image 26 in the circumferential direction to the circular arc of the cylindrical test object 1. The shape data obtained by phase shifting can be corrected by the axial position information. It should be noted that in the conventional method in which the phase shift image is changed by changing the grid projection condition, π / 2 is set for each image.
Since the offsets of 1 occur sequentially, it is necessary to correct them together, but in the method of performing the phase shift at the position in synchronization with the rotation as shown in FIG. 4, this correction need not be performed.

[0036]

As described above, the present invention is different from the phase shift moire method in the same image as the phase-shifted moire fringe data during shape measurement from the phase-shifted moire fringe data obtained by the two-dimensional area sensor. Since the position variation detection of the test object is performed by using the same image as the phase-shifted moire fringe data, the position variation during shape measurement can be detected without using the position variation detection sensor. It is possible to eliminate the need for calibration of the sensor for detecting the position change,
The shape measurement can be simplified and the measurement accuracy can be improved.

A pattern light having regularity is projected onto a region of the same image as the moiré fringe data phase-shifted during shape measurement, in which moiré fringes are not generated, and the position variation of the test object is detected from the position or the pattern shape. By doing so, it is possible to easily detect the position variation during shape measurement.

Further, due to the change in the pattern of the non-moiré pattern portion at the end of the lattice pattern for forming the moiré fringes formed in the region of the same image as the phase-shifted moiré fringe data, where the moiré fringes are not generated. By detecting the position variation of the specimen, the position variation during the shape measurement can be detected with a simpler configuration.

Further, by detecting the position variation of the object to be inspected from the moire fringe image which does not phase-shift during the shape measurement,
It is possible to increase the area of the shape that can be detected at one time and also to detect the rotational shake of the test object.

Furthermore, the phase shift error can be reduced by changing the phase shift calculation region used for shape measurement according to the position variation detection data of the object to be subjected to the phase shift calculation.

Further, by controlling so that the positional relationship between the measuring head and the test object becomes constant according to the position variation of the test object, the influence of rotational shake can be suppressed and the phase shift error can be reduced. it can.

[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 two-dimensional area sensor, a lattice pattern, and a cylindrical test object.

FIG. 4 is an arrangement diagram showing a measurement region of a pixel row in a moire fringe image pickup region of a two-dimensional area sensor.

FIG. 5 is an explanatory diagram showing measurement data for each time of a pixel row in a moire fringe image pickup area.

FIG. 6 is an explanatory diagram showing measurement data of pixel rows in a moire fringe image pickup area.

FIG. 7 is a diagram showing an image obtained by capturing moire fringes.

FIG. 8 is a perspective view showing a configuration of a measuring head having a spot light source.

FIG. 9 is an arrangement diagram when a moire fringe and a spot image are picked up by a two-dimensional area sensor.

FIG. 10 is a diagram showing images of moire fringes and spot images.

FIG. 11 is a schematic view showing an end pattern portion through which reflected light from a cylindrical test object having a lattice pattern does not pass again.

FIG. 12 is a diagram showing an image including an arc-shaped lattice pattern formed by end pattern portions.

FIG. 13 is a configuration diagram of another lattice pattern forming an image including an arc-shaped lattice pattern.

FIG. 14 is a diagram showing an image obtained by capturing an image of a cylindrical test object by using a normal moire method.

FIG. 15 is a schematic diagram showing a limited area where moiré processing is performed.

FIG. 16 is a schematic diagram showing lines for performing a phase shift.

FIG. 17 is a layout diagram showing a conventional configuration.

FIG. 18 is a layout diagram showing the configuration of another conventional example.

FIG. 19 is an explanatory diagram of a lattice projection type moire method.

FIG. 20 is an explanatory diagram of a real lattice type moire method.

FIG. 21 is a layout diagram of a light source, an observation point, a grid, and an object by the moire method.

FIG. 22 is a layout diagram of a light source, an observation point, a lattice, and an object of a real lattice type moire method.

FIG. 23 is a light intensity characteristic diagram of a phase-modulated fringe image.

[Explanation of symbols]

1; cylindrical test object, 2; shape measuring device, 3; gripping jig,
4; rotary motor, 5; motorized stage, 6; measuring head,
10; light source, 11; lattice pattern, 12; lens, 1
3; two-dimensional area sensor, 14; spot light source.

Continued front page    (72) Inventor Osamu Nakayama             1-3-3 Nakamagome, Ota-ku, Tokyo Stocks             Company Ricoh F term (reference) 2F065 AA06 AA47 AA49 BB05 FF08                       GG04 HH04 HH06 JJ03 JJ26                       MM04 MM07 PP02 PP18 QQ00                       QQ17 QQ24

Claims (10)

[Claims] 1. A test object is rotated to accurately shift a moire fringe of a specific fringe order by a desired phase, a measurement region is limited to the vicinity of the fringe order, and a phase shift obtained by a two-dimensional area sensor is performed. A shape measuring method characterized in that a shape is measured from moire fringe data, and a position variation of an object to be detected is detected from the same image as the moiré fringe data phase-shifted during the shape measurement by a method different from the phase shift moire method. 2. A pattern light having regularity is projected onto a region of the same image as the moire fringe data phase-shifted during the shape measurement, in which no moire fringes are generated, and the position or the pattern shape is used to determine the position of the object to be inspected. The surface shape measuring method according to claim 1, wherein fluctuations are detected. 3. A portion of the same pattern as the moire fringe data phase-shifted during the shape measurement, where moire fringes are not formed in an area of the same image, where moire fringes are not formed. The surface shape measuring method according to claim 1, wherein the position variation of the object is detected from the change of the pattern. 4. An object to be measured is rotated to accurately shift a moire fringe of a specific fringe order by a desired phase, a measurement region is limited to the vicinity of the fringe order, and a phase shift obtained by a two-dimensional area sensor is performed. A surface shape measuring method characterized in that a shape is measured from moire fringe data, and a position variation of an object to be inspected is detected from a moire fringe image without phase shift. 5. The surface shape measuring method according to claim 1, wherein a phase shift calculation region used for shape measurement is changed in accordance with position variation detection data of the object to be subjected to phase shift calculation. . 6. The shape measuring apparatus according to claim 1, wherein control is performed so that the positional relationship between the measuring head and the test object becomes constant according to the position variation of the test object. 7. A measuring head having a physical lattice type moire optical system having a two-dimensional area sensor, and a gripping and rotating mechanism for holding and rotating an object to be inspected. The moire fringes of the fringe order are 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 moiré fringe data obtained by the two-dimensional area sensor, and the shape is measured during shape measurement. A shape measuring device characterized by detecting a position variation of an object to be inspected in the same image as the phase-shifted moire fringe data by a method different from the phase-shift moire method. 8. The pattern light having regularity is projected onto a region of the same image as the moiré fringe data phase-shifted during the shape measurement, in which no moiré fringes are generated, and the position or the pattern shape is used to determine the position of the object to be inspected. The surface profile measuring apparatus according to claim 7, which detects fluctuations. 9. A portion of a lattice pattern end portion for forming moire fringes, which is formed in a region where no moire fringes are generated in the same image as the moire fringe data phase-shifted during the shape measurement, where moire is not formed. The surface profile measuring apparatus according to claim 7, wherein the position variation of the object to be inspected is detected from the change of the pattern. 10. A measuring head having a physical lattice type moire optical system having a two-dimensional area sensor, and a grip rotating mechanism for holding and rotating an object to be inspected. The moire fringes of the fringe order are accurately shifted by a desired phase, the measurement area is limited to the vicinity of the fringe order, the shape measurement is performed from the phase-shifted moiré fringe data obtained by the two-dimensional area sensor, and the moiré without the phase shift is obtained. A surface shape measuring device characterized by detecting a positional variation of a test object from a fringe image.