JP2003042734A - Method and apparatus for measurement of surface shape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and an apparatus wherein a phase shift method can be applied to a stereolattice-type moire method simply and without any trouble, without a need of the movement operation of a lattice pattern in order to change the phase of moire fringes. SOLUTION: In a stereolattice-type moire optical system, a lattice pattern structure 11 in which lattice patterns 15, 16, 17 formed by filters 12, 13, 14 used to absorb beams of light in at least three kinds of different wavelength bands is used, a plurality of moire fringe images formed in the beams of light at a plurality of wavelengths absorbed by the respective filters 12, 13, 14 are imaged, the phase shift method is applied, and the movement mechanism of the lattice patterns required for performing a phase shift in conventional cases is not required. As a result, the waiting time for a movement in order to acquire a plurality of phase-shited moire images can be eliminated, the measuring time can be shortened, and a measurement error due to the movement accuracy of the movement mechanism can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to surface shape measurement using the moire method for detecting surface defects of an object to be inspected and detecting uneven defects such as ridge bulges, undulations, and dents with little three-dimensional shape change. The present invention relates to a method and a surface shape measuring device.

[0002]

2. Description of the Related Art As a conventional defect inspection method for a cylindrical test object such as a photosensitive drum, Japanese Patent Laid-Open No. 2-201142 is known.
Japanese Patent Laid-Open No. 4-169840 and the like. FIG. 20 is a perspective view showing an example of Japanese Patent Laid-Open No. 2-201242. In the figure, first, the light source 10
The laser light beam 102 from 1 is irradiated so as to scan in the axial direction of the photosensitive drum 104 via the rotary polygon mirror 103, and the scanning light is reflected on the surface of the photosensitive layer of the photosensitive drum 104. The photosensitive drum 104 is a drive motor 105.
Is driven to rotate. The reflected light from the normal surface almost enters the light receiver 106, the intensity of the reflected light is detected, and the detection output is input to a predetermined arithmetic processing unit or the like.

Such processing shown in the example of the publication is for detecting an abnormal surface condition when the detected value is abnormally lowered.

On the other hand, FIG. 21 is shown in Japanese Unexamined Patent Publication No. 4-169840.
It is a schematic perspective view which shows the method of the example of the publication. In the figure, a slit light 112 is projected from a light projector 110 equipped with a halogen light source or the like toward a photosensitive drum 111. The scattered light scattered by the surface defects of the photoconductor drum 111 is condensed by the lens 113, and the line sensor 11
Light is received at 4. The line sensor 114 has a pixel row, and its light receiving range is a range indicated by E on the surface of the photosensitive drum 111.

Such processing shown in the example of the publication is for detecting an abnormality of scattered light due to a defect.

Defects due to pinholes, dents, abrasions, inclusion of bubbles, cracks, dust and the like, and various defects such as uneven thickness of the photosensitive layer, liquid dripping and scratches on the support occur on the photosensitive member. there is a possibility.

In the case of the conventional optical inspection apparatus as described above, a high detection power is exhibited for a defect having a large rate of change in surface unevenness such as a defect caused by the attachment of pinholes, dents, scratches, dust and the like. However, there is a problem in the detection accuracy for defects with a small rate of change in unevenness such as unevenness of the thickness of the photosensitive layer, or defects with no change in unevenness on the surface of the photosensitive member such as scratches on the support. .

On the other hand, a moire method (three-dimensional measurement method using moire topography) is one of the three-dimensional measurement methods. The Moire method includes a physical lattice type and a lattice projection type, which are widely used in various fields.

As shown in FIG. 22, the lattice projection type moire method is used for projecting and observing small lattices G ₁ and G, respectively.
₂ is arranged, the grating G ₁ is projected onto the object by the lens L ₁ , the grating line deformed according to the object shape is imaged on the other grating G ₂ through the lens L ₂ , and the fringe contour line is drawn from the reference plane. It is generated at predetermined distances h ₁ , h ₂ , h ₃ , ....

On the other hand, the actual lattice type moire method is shown in FIG.
As shown in FIG. 22, one grid G is installed on the reference plane, and FIG.
With the point light source S ₁ placed at the position of the lens L ₁ and the observation eye e placed at the position of the lens L ₂ , the shadow of the light source S ₁ of the grating G is cast on the object, and the shadow of the grating G deformed according to the object shape is changed. This is a method of observing moire fringes generated by the grid G and the shadow of the deformed grid by forming a shadow and observing the shadow with an observation eye e through the grid G.

Conventionally, the three-dimensional shape measuring method based on the moire method can intuitively grasp an object, but (1) it is difficult to determine unevenness, and (2) it is not suitable for highly sensitive three-dimensional measurement ( At present, the interval between the moire fringe contour lines is limited to about 10 μm), and (3) the visibility of moire fringes is not uniform for each fringe, making it difficult to handle moire images as an image processing target. There is.

This problem is that in the case of the grid projection type moire method, since two grids are used, one of them is moved to shift the fringe scanning, that is, the phase of the moire fringes. This makes it possible to equivalently divide the contour interval finely, and to determine the unevenness of the target and improve the measurement sensitivity. However, in the case of the real grid type moire method, since there is only one grid, the grid projection Even if the phase shift such as the type Moire method is performed, it is not possible to change the phase while aligning the phases of the fringe contour lines of all orders.

To solve such a problem, for example, Japanese Unexamined Patent Publication No. 4-147001 (Japanese Patent No. 2887517) reports a measuring method in which a phase shift method is combined with a physical lattice type moire method. There is. That is, by performing the vertical movement of the lattice plane and the horizontal movement of the light source or the observation point at the same time, the phase of the fringes of each order is substantially aligned without causing a large change in the phase of the moire fringes of each order. The fringe phase can be shifted with respect to the measurement target. Thereby, it is possible to process a plurality of moire fringe images based on the principle of the high-speed inspection method (phase shift method), which increases the density of the measurement points by the moire fringes with respect to the measurement target, and about one cycle of the moire fringes. About 1 / 40-1
A physical division of about / 100 is possible, and it is possible to determine the unevenness of the surface and improve the measurement sensitivity, which has been difficult with only the real lattice type moire method.

[0014]

However, when the phase shift method is applied to the actual lattice type moire method as in the example of Japanese Patent Application Laid-Open No. 4-147001, the apparatus configuration is complicated for moving the lattice. Becomes In particular, it is intended to shift all fringe orders almost accurately, and it is realized by simultaneously moving the lattice plane vertically and the light source or the observation point horizontally in two directions. The device configuration such as the mechanism becomes complicated. In addition, there is a problem in that an error of a lattice position due to such movement has an influence.

Therefore, according to the present invention, the phase shift method can be applied to the real lattice type moire method easily and without any trouble, so that a cylindrical object such as a roller component or a planar object such as a liquid crystal can be obtained. An object of the present invention is to provide a surface shape measuring method and a surface shape measuring apparatus capable of performing three-dimensional measurement of the surface shape of a specimen at high speed and with high accuracy.

In particular, the present invention provides a surface shape measuring method and a surface shape measuring apparatus which do not require a movement operation of a grid pattern for changing the phase of moire fringes and can perform high-speed and highly accurate measurement with a simple structure. With the goal.

[0017]

According to a first aspect of the present invention, there is provided a surface shape measuring method comprising: a light source for generating moire fringes; and a plurality of filters for absorbing light of at least three different wavelength bands. A lattice-pattern structure, wherein a lattice-pattern moire optical system having a lattice-pattern structure formed by stacking lattice patterns and a light-receiving system including a lens for capturing moire fringes and an imaging camera is used as an inspection optical system. The shape of the surface of the test object is three-dimensionally calculated by arithmetic processing based on the image data of at least three phase-shifted moire fringes imaged by the light receiving system for each light of a plurality of wavelengths absorbed by each filter of the body. I tried to measure it.

Therefore, in the actual lattice type moire optical system, a lattice pattern structure is used in which lattice patterns formed by filters for absorbing at least three kinds of different wavelength bands are overlapped, and a plurality of filters are used for absorption. By capturing multiple moire fringe images formed for each wavelength of light and applying the phase shift method, the grid pattern moving mechanism that was required to perform phase shift in the past is no longer necessary. It is possible to eliminate the time to wait for the movement to acquire the shifted moire image, shorten the measurement time, and reduce the measurement error due to the movement accuracy of the movement mechanism.

According to a second aspect of the present invention, in the surface shape measuring method according to the first aspect, the lattice pitches of the respective lattice patterns are different so that the periods of the moire fringes generated by the respective lattice patterns are equal. The lattice pattern structure formed in 1. was used.

Therefore, in order to realize the invention of claim 1, the grid pitch of each grid pattern of the grid pattern structure is set such that the contour line intervals of the moire fringes are set to be constant, so that a wider range of measurement can be performed. It can be performed.

According to a third aspect of the present invention, in the surface shape measuring method according to the first aspect, the optical axis of each of the lattice patterns and the image pickup camera are arranged so that the periods of Moire fringes generated by the respective lattice patterns become equal. The lattice pattern structures are formed by forming different angles with each other and stacking them.

Therefore, in realizing the invention of claim 1, the optical axes of the respective lattice patterns of the lattice pattern structure are formed with different angles formed by the image pickup camera, and the contour line intervals of moire fringes are constant. By setting so that
A wider range of measurements can be made.

The invention according to claim 4 is the same as claims 1 to 3.
In the surface shape measuring method according to any one of items 1 to 5, a line sensor camera is used as the imaging camera, and a relative positional relationship between the object to be inspected and the moire optical system in a direction orthogonal to a line direction of the line sensor camera. Was sequentially moved to measure the entire shape of the surface of the test object.

Therefore, a line sensor camera is used as the image pickup camera, and the relative positional relationship between the object to be inspected and the moire optical system is sequentially moved in a direction orthogonal to the line direction of the line sensor camera, whereby a continuous sheet shape is formed. It is possible to measure the waviness in the radial direction of the object to be measured or the drum-shaped (cylindrical) object to be measured at high speed.

According to a fifth aspect of the present invention, there is provided a surface shape measuring device having a light source for generating moire fringes and a grating pattern, and a light receiving system including a lens for capturing the moire fringes and an image pickup camera. Surface shape measuring apparatus using the Moire optical system as an inspection optical system, wherein a plurality of the lattice patterns are formed by respective filters that absorb light of at least three different wavelength bands, and the lattice pattern structure is superposed. And a calculation process based on the image data of at least three phase-shifted moire fringes imaged by the imaging camera for each light of a plurality of wavelengths absorbed by each of the filters of the lattice pattern structure. Arithmetic processing means for three-dimensionally measuring the shape.

Therefore, in the actual lattice type moire optical system, a lattice pattern structure is used in which lattice patterns formed by filters for absorbing light of at least three different wavelength bands are superposed, and a plurality of filters are used for absorption. By capturing multiple moire fringe images formed for each wavelength of light and applying the phase shift method, the grid pattern moving mechanism that was required to perform phase shift in the past is no longer necessary. It is possible to eliminate the time to wait for the movement to acquire the shifted moire image, shorten the measurement time, and reduce the measurement error due to the movement accuracy of the movement mechanism.

According to a sixth aspect of the present invention, there is provided a surface shape measuring apparatus which has a light source for generating moire fringes and a grating pattern, and a light receiving system including a lens for capturing the moire fringes and an imaging camera. A surface shape measuring apparatus using the moire optical system as an inspection optical system, wherein the light source is a white light source, the imaging camera is a color camera, and a plurality of filters are provided to absorb light of three different wavelength bands. A lattice pattern structure which is formed by stacking the lattice patterns and has a wavelength band absorbed by the filter portion of each layer that is equal to or greater than a wavelength band that passes through each color filter of the color camera, and the lattice pattern structure. The image data of three phase-shifted moire fringes imaged by the color camera for each of a plurality of wavelengths of light absorbed by the filters. And processing means for measuring the shape of the test object surface three-dimensionally by the arithmetic processing based on the data,
Equipped with.

Therefore, by forming a lattice pattern structure having a lattice pattern having a complementary color relationship with the color filter characteristics of a commonly used color camera, it is possible to provide a moire optical system of the actual lattice type at a lower cost. Becomes

According to a seventh aspect of the present invention, there is provided a surface shape measuring apparatus which has a light source for generating moire fringes and a grating pattern, and a light receiving system including a lens for imaging the moire fringes and an imaging camera. Surface shape measuring apparatus using the moiré optical system as an inspection optical system, wherein the light source is a light source having at least three different wavelength characteristics, and the light emission control means emits the light sources at different timings for each light source. And a lattice pattern structure in which a plurality of the lattice patterns are formed and overlapped by filters that absorb light of different wavelength bands of each of the light sources, emission timing of each of the light sources, and an imaging operation by the imaging camera. A synchronizing means for synchronizing with the image pickup camera for each light of a plurality of wavelengths absorbed by each of the filters of the lattice pattern structure. Ri comprises a processing unit for measuring the shape of the test object surface three-dimensionally, the by arithmetic processing based on the image data of at least three phase-shifted moiré fringes imaged.

Therefore, by turning on a plurality of light sources at different timings, it is possible to obtain a plurality of phase shift images with an ordinary black and white camera, and it is possible to provide an inexpensive real grating type moire optical system. Become.

The surface shape measuring apparatus according to the invention of claim 8 is a substantial lattice type having a light source and a grating pattern for generating moire fringes, and a light receiving system including a lens for imaging the moire fringes and an imaging camera. Surface shape measuring apparatus using the Moire optical system as an inspection optical system, wherein a plurality of the lattice patterns are formed by respective filters that absorb light of at least three different wavelength bands, and the lattice pattern structure is superposed. A plurality of bandpass filters arranged between the light source and the grating pattern structure to pass light of each wavelength included in each wavelength band, and the light source and the grating pattern structure in these bandpass filters. A filter switching mechanism for sequentially switching the bandpass filters located on the optical path between the body and the body, the switching operation of each bandpass filter, and the image pickup by the image pickup camera. And synchronization means for synchronizing the operation,
The shape of the surface of the object to be inspected is calculated by arithmetic processing based on the image data of at least three phase-shifted moire fringes imaged by the imaging camera for each light of a plurality of wavelengths absorbed by each filter of the lattice pattern structure. Arithmetic processing means for three-dimensionally measuring.

Therefore, by synchronizing with changing the wavelength band of the stripes projected on the lattice pattern of the lattice pattern structure for a single light source, the image is taken by the image pickup camera at different timings, so that a normal black and white camera can be used. Since it is possible to obtain a plurality of phase shift images, it is possible to provide an inexpensive real grating type moire optical system. Further, since only the light of the required wavelength band can be irradiated onto the lattice pattern, moire fringes can be visually observed, which is advantageous for performing work such as setting.

According to a ninth aspect of the present invention, there is provided a surface shape measuring apparatus having a light source and a grating pattern for generating moire fringes, and a light receiving system including a lens for capturing the moire fringes and an imaging camera. Surface shape measuring apparatus using the Moire optical system as an inspection optical system, wherein a plurality of the lattice patterns are formed by respective filters that absorb light of at least three different wavelength bands, and the lattice pattern structure is superposed. And a plurality of band-pass filters that are arranged between the lattice pattern structure and the image-capturing surface of the image-capturing camera and that pass light of each wavelength included in each of the wavelength bands,
A filter switching mechanism that sequentially switches band filters located on the optical path between the grating pattern structure and the imaging surface of the imaging camera in these band filters, switching operation of each band filter, and imaging by the imaging camera. Based on image data of at least three phase-shifted moire fringes imaged by the imaging camera for each of a plurality of wavelengths of light absorbed by each of the filters of the lattice pattern structure. Arithmetic processing means for three-dimensionally measuring the shape of the surface of the test object by arithmetic processing.

Therefore, in synchronism with the switching of the wavelength band of the moire fringes input to the image pickup surface of the image pickup camera, images are picked up by the image pickup camera at different timings, and a plurality of phase shifts are made by one ordinary monochrome camera. Since a moire image can be obtained, it is possible to provide an inexpensive real lattice type moire optical system. Further, since it is possible to dispose the band-filter switching mechanism for acquiring the moire image in the vicinity of the imaging camera, it is possible to collect the control signals in one place.

According to a tenth aspect of the present invention, there is provided a surface shape measuring apparatus which has a light source for generating moire fringes and a grating pattern, and a light receiving system including a lens for capturing the moire fringes and an image pickup camera, and a light receiving system. Surface shape measuring apparatus using the Moire optical system as an inspection optical system, wherein a plurality of the lattice patterns are formed by respective filters that absorb light of at least three different wavelength bands, and the lattice pattern structure is superposed. And a plurality of band-pass filters that are arranged between the lattice pattern structure and the image-capturing surface of the image-capturing camera and that pass light of each wavelength included in each of the wavelength bands,
A plurality of imaging cameras that respectively capture moire fringes due to the light that has passed through the band-pass filters, and a plurality of wavelengths of light absorbed by the filters of the lattice pattern structure are captured by the respective imaging cameras. Arithmetic processing means for three-dimensionally measuring the shape of the surface of the test object by arithmetic processing based on at least three phase-shifted moire fringe image data.

Therefore, a plurality of imaging cameras for acquiring images of respective wavelength bands forming moire fringes can simultaneously acquire a plurality of phase-shifted moire images, thereby enabling high-speed surface shape measurement. .

According to an eleventh aspect of the present invention, in the surface profile measuring apparatus according to any one of the fifth to tenth aspects, the image pickup camera is a line sensor camera, and the line sensor camera is arranged in a direction orthogonal to a line direction of the line sensor camera. A sub-scanning moving unit that sequentially moves the relative positional relationship between the test object and the moire optical system is provided.

Therefore, a line sensor camera is used as the image pickup camera, and the relative positional relationship between the object and the moire optical system is sequentially moved in a direction orthogonal to the line direction of the line sensor camera, whereby a continuous sheet shape is formed. It is possible to measure the waviness in the radial direction of the object to be measured or the drum-shaped (cylindrical) object to be measured at high speed.

According to a twelfth aspect of the present invention, in the surface profile measuring apparatus according to the seventh aspect, the image pickup camera is a line sensor camera, and the object and the moire are arranged in a direction orthogonal to a line direction of the line sensor camera. A sub-scanning moving unit that sequentially moves the relative positional relationship with the optical system is provided, and the synchronizing unit emits the light source having a different emission wavelength for each line in synchronization with each line light reception timing of the line sensor camera. .

Therefore, in the surface profile measuring apparatus according to the seventh aspect, the image pickup camera is a line sensor camera, and the relative positional relationship between the object to be inspected and the moire optical system in the direction orthogonal to the line direction of the line sensor camera. While sequentially moving, and by emitting light sources having different emission wavelengths for each line in synchronization with each line light receiving timing of the line sensor camera, a continuous sheet-shaped measurement target,
The undulation in the radial direction of a drum-shaped (cylindrical) measurement target can be measured at high speed.

According to a thirteenth aspect of the present invention, in the surface profile measuring apparatus according to the eighth aspect, the imaging camera is a line sensor camera, and the object and the moire are arranged in a direction orthogonal to a line direction of the line sensor camera. A sub-scanning moving unit that sequentially moves the relative positional relationship with the optical system is provided, and the synchronizing unit synchronizes with each line light reception timing of the line sensor camera, and between the light source and the lattice pattern structure. The bandpass filters located on the optical path are sequentially switched.

Therefore, in the surface shape measuring apparatus according to the eighth aspect, the image pickup camera is a line sensor camera, and the relative positional relationship between the object to be inspected and the moire optical system in the direction orthogonal to the line direction of the line sensor camera. While sequentially moving, while sequentially switching the bandpass filter located on the optical path between the light source and the grating pattern structure in synchronization with each line light receiving timing of the line sensor camera, continuous sheet-like measurement object or The undulation in the radial direction of the drum-shaped (cylindrical) measurement target can be measured at high speed.

According to a fourteenth aspect of the present invention, in the surface profile measuring apparatus according to the ninth aspect, the imaging camera is a line sensor camera, and the object and the moire are arranged in a direction orthogonal to a line direction of the line sensor camera. A sub-scanning moving means for sequentially moving the relative positional relationship with the optical system is provided, and the synchronizing means synchronizes with each line light receiving timing of the line sensor camera, and the lattice pattern structure and the image pickup surface of the image pickup camera. The band-pass filters located on the optical path between and are sequentially switched.

Therefore, in the surface shape measuring apparatus according to the ninth aspect, the image pickup camera is a line sensor camera, and the relative positional relationship between the object to be inspected and the moire optical system in the direction orthogonal to the line direction of the line sensor camera. Of the continuous sheet-like by sequentially switching the band filters located on the optical path between the grating pattern structure and the imaging surface of the imaging camera in synchronism with each line light receiving timing of the line sensor camera. It becomes possible to measure the waviness in the radial direction of the measurement target or the drum-shaped (cylindrical) measurement target at high speed.

According to a fifteenth aspect of the present invention, in the surface shape measuring apparatus according to any one of the fifth to fourteenth aspects, the lattice pitch of each of the lattice patterns of the lattice pattern structure is a moire generated by each of the lattice patterns. They are formed with different grid pitches so that the stripes have the same period.

Therefore, in realizing the invention described in claims 5 to 14, the grid pitch of each grid pattern of the grid pattern structure is set so that the contour line intervals of the moire fringes are set to be constant, thereby making a wider range. Can be measured.

According to a sixteenth aspect of the present invention, in the surface profile measuring apparatus according to any one of the fifth to fourteenth aspects, the lattice pattern structure is configured so that the moire fringes generated by the respective lattice patterns have the same period. , The optical axes of the grid patterns and the imaging camera are formed at different angles, and the structures are stacked.

Therefore, in realizing the invention described in claims 5 to 14, the angle between the optical axis of each grating pattern of the grating pattern structure and the image pickup camera is made different, and the contour interval of the moire fringes is formed. By setting so that is constant, a wider range of measurement can be performed.

[0049]

BEST MODE FOR CARRYING OUT THE INVENTION <First Embodiment> A first embodiment of the present invention will be described with reference to FIGS.

First, prior to the description of the present embodiment, the principle of the three-dimensional measurement method by the moire method and the phase shift method, which are the basis thereof, will be described.

[Principle of the three-dimensional measurement method by the moire method] The pitch of the gratings G ₁ and G ₂ is s, the distance between the light source S ₁ and the observation point S ₂ is d, the light source S ₁ , the observation point S ₂ and the lattice plane Distance from
And The gratings G ₁ and G _{2 on the} same plane both have a pitch s, but the gratings G ₁ and G ₂ are displaced from each other by ε in the plane (2πε / s in terms of the phase of the grating pitch). Then, the formed moire fringes can be expressed as cos (2π / s) [{dh−ε (h + 1)} / (h + 1)] (1) (FIG. 1). The moire fringes (contour lines) that are formed are
With the lattice plane as a reference (0th order), the fringe orders are sequentially counted as 1st order and 2nd order with increasing distance from the lattice plane. Therefore, the moire fringe having the fringe order N is set to cos2πN. As a result, contour lines of the N-th order moiré fringes position apart _{h N} from the reference _{plane, h N = {(Ns +} ε) l} / (d-Ns-ε) ........................ (2) Will be formed. This does not include the coordinate x of the position on the measurement surface, and is a unique value determined by the fringe order N (regardless of x). That is, it indicates that contour lines are formed.

In the case of the configuration shown in FIG. 2, S1 is used as a point light source, an observation point is placed at the position of S2, and one continuous (that is, ε = 0) grid pattern G is arranged. Corresponds to what you did (called a real lattice type). Since ε = 0, from the equation (2), h _N = Nsl / (d−Ns) ……………………………… (3) holds. However, although it is called a contour line, the interval Δ
h _N = h _{N + 1} −h _N is not constant and varies depending on the fringe order N.

[Explanation of Phase Shift Method] The phase-modulated fringe image is I = I (θ) = a (x, y) + b (x, y) cos (Φ (x, y) depending on the light intensity I. )
However, it can be expressed as a: offset bias, b: amplitude, θ: operable phase, Φ: phase value corresponding to height h (see FIG. 3).

What we want to obtain here is each point (x,
It is the phase Φ (x, y) at y). Since the bias and the amplitude are unknown components that change due to surface reflectance and dirt, three fringe images I ₁ = I (0) = a (x, y in which the phase θ is changed to 0, π / 2, π ) + B (x, y) cos (Φ
(x, y) + θ)) I ₂ = I (π / 2) = a (x, y) −b (x, y) sin (Φ
(x, y) + θ)) I ₃ = I (π) = a (x, y) −b (x, y) cos (Φ
(x, y) + θ)) is generated.

Φ (x, y) = tan ⁻¹ {(I ₃ −I ₂ ) / (I ₁ −I ₂ ) + π / 4} (4) The phase Φ (x, y) according to the equation (4). ) Is calculated, the reflectance and dirt components are removed, and the phase Φ at each point (x, y) is calculated.
(X, y) can be obtained.

<Application of the phase shift method to the three-dimensional measurement method by the moire method> First, as shown in FIG. 4, consider changing the position of the grating pattern shown in FIG. 1 by Δl in the optical axis direction. The contour line of the Nth-order moire fringes before movement is formed at the position of h _{N + 1} = {(N + 1) sl} / {d- (N + 1) s} (5) from the equation (3).

Next, the position of the lattice pattern is Δ in the optical axis direction.
The contour line of the Nth-order moiré fringe when moving by l is h ′
_{If N} , then h ′ _N = Ns (l + Δl) / (d−Ns) (6)

Here, as shown in FIG. 4, assuming that the contour position of the N + 1th order moiré fringes before moving the lattice pattern is set to the contour position of the Nth order moiré fringes after moving, (5) From the expression (6), {(N + 1) sl} / {d- (N + 1) s} = Ns (l + Δl) / (d-Ns) + Δl (7) When this equation (7) is solved for Δl, Δl = sl / {d− (N + 1) s} ... (8)

Therefore, consider changing l with respect to the moire fringe of the object to be inspected, imaging three times with Δl = 0, Δl / 4, and Δl / 2, and calculating the phase using the phase shift method.

As can be seen from the equations (3) and (8), the shift amount Δl differs depending on the fringe order N. Therefore, when the lattice pattern is changed by Δl, the phase shift can be accurately performed with a certain fringe order N, but it is shifted with other fringe orders.

However, for example, l = 200 mm, d = 7
When 0 mm, s = 83.3 μm (= 12 lines / mm), the contour line height h _N before changing is as shown in FIG. 5 from the equation (3). Further, the contour interval Δh _N = h _{N + 1}
The difference between −n _N and the contour interval Δh _N is as shown in FIG.

[Premise Configuration Example] As a premise example of the measuring device based on the above-mentioned principle, there is a configuration example shown in FIG. In the inspection optical system 1, a light source 2 and a grating pattern 3 are provided.
A lens 5 for capturing an image of moire fringes formed by the surface shape of a cylindrical test object 4 such as a photosensitive drum, and a light receiving system by a line sensor camera 6 as an image capturing camera are incorporated. These optical systems constitute a substance lattice type moire optical system of the principle as shown in FIG.

At a certain position, the inspection optical system 1 is made to face the surface of the cylindrical test object 4, and the cylindrical test object 4 is chucked.
The line sensor camera 6 images the moire fringes while rotating the rotary motor 8 via the.

By imaging the moire fringes of the cylindrical test object 4 by using the line sensor camera 6 in this way, the position of the cylindrical test object 4 is always substantially at the same height (in the circumferential direction). Since only a small range is imaged), it is possible to limit the measurement range to several fringe orders around a specific fringe order. For example, setting the measurement position of the cylindrical test object 4 so that the stripe order N = 1 to 3 in FIG.
It is sufficient to suppress the rotational runout to about 0.5 mm, which can be easily realized. Further, in this range, as can be seen from FIG. 6, since the difference between the contour line intervals Δh _N is only about 0.57 μm, there is no problem in measuring undulations or dents whose height difference is about several μm. It can be said that there is. Further, similarly, it can be said that there is no problem in measuring waviness and dents on a flat surface (paper, liquid crystal, optical disk, etc.).

As the measurement operation, first, after the first image capturing, the phase of the moire fringes is accurately shifted by π / 2 by a phase shift mechanism (not shown) as a desired phase, and the second image capturing is performed. Furthermore, the phase is accurately shifted by another π / 2 by the phase shift mechanism, and the third imaging is performed.
Based on the image data of the three phase-shifted moire fringes, the three-dimensional surface shape of the cylindrical test object 4 may be calculated from the arithmetic processing of the equation (4) in the arithmetic processing means (not shown). . That is, the image data obtained from the line sensor camera 6 is A / D-converted and then output to the arithmetic processing means such as a personal computer, and the arithmetic processing means performs the phase calculation by the arithmetic processing on the three phase-shifted image data. Is performed, and three-dimensional coordinates, that is, the surface shape is obtained based on the equation (4).

[Principle of this Embodiment] In the case of the premised configuration example shown in FIG. 7, in order to change the phase of the moire fringes, the grating pattern 3 is moved by a predetermined distance in the front-rear direction (optical axis direction). It is necessary to shift only.

Therefore, in the present embodiment, for example, in the preconditional configuration example as shown in FIG. 7, in order to make the front and rear shift operation of the lattice pattern 3 unnecessary, the lattice pattern 3 of the single layer structure is replaced with a diagram. The grid pattern structure 11 as shown in FIG. 8 is used. The lattice pattern structure 11 is formed, for example, at equal intervals by the filters 12, 13, and 14 at positions of Δl = 0, Δl / 4, and Δl / 2 corresponding to the respective phase positions as described above as the surface reference. In addition, a plurality of grid patterns 15, 16 and 17 are integrally stacked. These grid patterns 1
Reference numerals 5, 16 and 17 are assumed to absorb light of different wavelength bands and not transmit it. Specifically, the filter 12 is a filter that does not pass the wavelength band of blue B, the filter 13 is a filter that does not pass the wavelength band of red R, and the filter 14 is a filter that does not pass the wavelength band of green G. , 13,
As illustrated in FIG. 8, 14 are patterned so as to be displaced from each other. In the illustrated example, the layers are stacked in the order of RGB, but the stacking order is not limited to this, and if the wavelength band is different, the layers are not limited to RGB but may be configured by filters such as infrared, red, and blue. May be.

In the structure as shown in FIG. 7, if this lattice pattern structure 11 is used instead of the lattice pattern 3, it is absorbed by each filter 12, 13, or 14 in each lattice pattern 15, 16, 17. By selecting the wavelength band to be selected and capturing the image with the line sensor camera 6, it is possible to acquire an image of moire fringes for each wavelength band. In other words, as a whole, Δl = 0, Δl / 4, Δl / without the grid pattern structure 11 being shifted.
An image of three-half phase-shifted moire fringes can be acquired. As for the acquired images of the moire fringes, the phase calculation is performed by the arithmetic processing on the three phase-shifted image data in the arithmetic processing means, as described in the premise configuration example, and the equation (4) is used. The three-dimensional coordinates, that is, the surface shape is obtained based on the above.

Therefore, according to the present embodiment, the grating patterns 15, 16, 17 formed by the filters 12, 13, 14 for absorbing the light of at least three different wavelength bands in the real grating type moire optical system. Using a lattice pattern structure 11 in which the respective filters 12, 13,
A plurality of moiré fringe images formed for each of a plurality of wavelengths of light to be absorbed by 14 are captured by the line sensor camera 6 and the phase shift method is applied. No moving mechanism is required. As a result, it is possible to eliminate the time to wait for movement in order to acquire a plurality of phase-shifted moire images, shorten the measurement time, and reduce the measurement error due to the movement accuracy of the movement mechanism. .

<Second Embodiment> A second embodiment of the present invention will be described with reference to FIG. In the above-described first embodiment, the contour line intervals of the moire fringes are slightly different in each of the grid patterns 15, 16 and 17, but by limiting the height difference of the measurement target (see the section of the premise configuration example). The lattice pattern structure 11 has a structure in which the filters 12, 13 and 14 are laminated at equal pitches. However, if the height difference of the measurement target is larger than the above case, or if you want to eliminate the error and perform more accurate measurement,
It is necessary to make the contour intervals of the moire fringes uniform.

Therefore, in the present embodiment, the contour line intervals of the moire fringes are made uniform. In particular,
Since the contour line interval of the moire fringes is expressed by the above-mentioned equation (6), if the pitch s is s (φ), then h ′ _N = Ns (φ) (l + Δl) / (d−Ns (φ)) ... …………… (6) ′.

To keep Δh _N = h _{N + 1} −h _N constant,
Assuming that the other Nth-order moire fringes are present between the Nth-order and N + 1th-order moiré fringes of one of the superposed lattice patterns, h _N + (h _{N + 1} −h _N ) (φ / _{2π) = h 'N + Δl} .................. (9) is satisfied. Substituting equation (6) 'into equation (9) and rearranging factorials of N (reference 1 “Shape measurement by the phase-shifting physical lattice type moire method” Kodera et al., Journal of Precision Engineering Vol.
No.10, 1999) and Δl = sl (d−p) (φ / 2π) / {d ² −2pd−p ² (φ / 2π)} …………………………………… (10) s (φ) = s / [1+ {p (d−p) (φ / 2π) / (d ² −2pd−p ² (φ / 2π))}] ……………………………… (11) This phase φ is φ used for phase shift, and φ =
Phase shift is made possible by constructing the lattice pattern structure 11 by superimposing the lattice patterns 15, 16 and 17 with Δl, s (φ) such that 0, π / 2, π. Is.

Further, similarly to the case of the above-mentioned reference document 1, each of the grating patterns having the same pitch is Δθ = cos ⁻¹ (s (φ)) ……………………………… (12 ), The phase shift is possible by forming the lattice pattern structure 11 by superimposing it at an angle. That is,
The lattice pattern structures 11 are formed by forming the lattice patterns 15, 16 and 17 at different angles from each other and the line sensor camera 6 (imaging camera).

Therefore, according to the present embodiment, in any case, since the grid pattern structure 11 is constructed so that the contour line intervals of the moire fringes are constant, it is possible to measure a wider range. .

<Third Embodiment> A third embodiment of the present invention will be described with reference to FIG. The same parts as those shown in the above-described embodiments are designated by the same reference numerals, and the description thereof will be omitted (the same applies to each of the following embodiments).

In the present embodiment, a combination of the above-mentioned lattice pattern structure 11, a white light source 21 corresponding to the light source 2, and a color camera 22 as an image pickup camera corresponding to the line sensor camera 6 is used to form an actual lattice type. The moiré optical system is constructed. Here, in the case of the present embodiment, the wavelength bands absorbed by the respective filters 12, 13, 14 forming the grating patterns 15, 16, 17 are determined by the RGB color filters of the color camera 22. Same as or wider than the wavelength band (R
It is formed as a wavelength band that passes through each color filter of GB) and is configured as the grating pattern structure 11 having Δl and the grating pitch as described in the first or second embodiment. That is, the lattice pattern structure 11 including the lattice patterns 15, 16 and 17 having a complementary color relationship with the color filter characteristics of the color camera 22 that is normally used is used.

Calculation based on the image data of the three phase-shifted moire fringes imaged by the color camera 22 for each light of a plurality of wavelengths absorbed by the filters 12, 13, 14 of the lattice pattern structure 11 as described above. The shape of the surface of the test object is three-dimensionally measured by the arithmetic processing in the processing means.

Therefore, according to the present embodiment, the color camera 22 is used, and it is constituted by the grid patterns 15, 16 and 17 which have a complementary color relationship with the color filter characteristics of the color camera 22 which is normally used. By using the lattice pattern structure 11 as described above, it is possible to provide the moire optical system of the actual lattice type at a lower cost.

<Fourth Embodiment> A fourth embodiment of the present invention will be described with reference to FIGS.

The present embodiment is a combination including the above-mentioned grating pattern structure 11 and three light sources 23r, 23g and 23b having three different emission wavelength characteristics corresponding to the light source 2 and the line sensor camera 6. And a three-dimensional light source 23r, 23g,
A light emission timing control unit 24 is provided as a light emission control unit that controls the light emission timing so that these light sources 23b emit light at different timings. The light emission timing control unit 24 outputs a camera synchronization signal to the line sensor camera 6 so that each light source 23
A function of a synchronization unit that synchronizes the light emission timings of r, 23g, and 23b with the imaging operation of the line sensor camera 6 is realized.

In such a structure, each light source 23r, 23g, 2 is controlled by the light emission timing control section 24.
As shown in FIG. 11, the image 3b is sequentially emitted at different emission timings, and a camera synchronization signal is used to synchronize the emission timings of the respective light sources 23r, 23g, and 23b with the image of the moire fringes by the lattice pattern structure 11. Is captured by the line sensor camera 6 and each filter 12, 13, 1
Obtain every 4th image. Since this image corresponds to an image in which the moire fringes are phase-shifted, at least an image picked up by the line sensor camera 6 is obtained for each light of a plurality of wavelengths absorbed by the filters 12, 13, 14 of the lattice pattern structure 11. The shape of the surface of the object to be inspected can be three-dimensionally measured by the arithmetic processing in the arithmetic processing means based on the image data of the three phase-shifted moire fringes.

Therefore, according to the present embodiment, a plurality of light sources 23r, 23g, and 23b are turned on at different timings to obtain a plurality of phase shift images with a normal monochrome camera as the line sensor camera 6. Therefore, it is possible to provide an inexpensive physical lattice type moire optical system.

Here, in the example shown in FIG. 10, three light sources 23r, 23g, 23b and a grid pattern 1 of RGB three layers are used.
Although the configuration example of the lattice pattern structure 11 of 5, 16, and 17 has been shown, a combination of a lattice pattern structure in which three or more light sources and lattice patterns formed by filters corresponding to these light sources are laminated. Can also be realized by. For example, if four light sources are used, φ
= 0, π / 2, π, 3π / 2, and the image of each moire fringe is I, the phase φ (x, y) at each pixel is φ (x, y) = tan ⁻¹ (I _{φ = 3π / 2-Iφ = π / 2} ) / ( _{Iφ = 0-} Iφ _{= π} ) It can be expressed by (13). Further, by setting the number to three or more, the variation in the imaging data and noise are averaged, so that the accuracy of measurement is improved. In this situation,
The same applies to each of the following embodiments.

<Fifth Embodiment> A fifth embodiment of the present invention will be described with reference to FIGS.

The present embodiment corresponds to the respective wavelength bands of the filters 12, 13 and 14 arranged between the above-mentioned grating pattern structure 11 and the light source 2 and the grating pattern structure 11. Three band-pass filters 25r, 25g, 25b that pass light of each wavelength included in each wavelength band, and one of these band-pass filters 25r, 25g, 25b is used as light between the light source 2 and the grating pattern structure 11. A combination of a filter switching mechanism (not shown) that performs a switching operation so as to be positioned on the road constitutes a moire optical system of a physical lattice type. With respect to this filter switching mechanism, a switching timing control unit 26 that controls the switching timing so that the band-pass filters 25r, 25g, 25b are positioned on the optical path between the light source 2 and the grating pattern structure 11 at different timings. The switching timing control unit 26 outputs a camera synchronization signal to the line sensor camera 6 so that the selection timing of each band filter 25r, 25g, 25b and the imaging operation by the line sensor camera 6 are performed. The function of the synchronizing means for synchronizing is realized.

In such a configuration, a plurality of band filters 25r, 25g, 25b installed between the light source 2 and the grating pattern structure 11 are changed by the filter switching mechanism (see FIG. 13), and the band filters 25r, 25r, 25 g
Alternatively, the line sensor camera 6 can perform imaging at different timings for each 25b, and the shape of the surface of the object to be inspected can be measured by each moire fringe data and the phase shift method. For example, as shown in the figure, the light passing through the bandpass filter 25b of wavelength B (blue) passes through the grating pattern 15 of the filter 12 that does not pass the wavelength B (blue) at the top, so that the light of blue Moire occurs. Similarly, the moire fringes having different phases can be acquired by the grating patterns 16 and 17 having different heights in other wavelength bands by the bandpass filters 25g and 25r.

Therefore, according to the present embodiment, in synchronization with changing the wavelength band of the stripes projected on the grating patterns 15, 16 and 17 of the grating pattern structure 11 for the single light source 2, By capturing images with the line sensor camera 6 at different timings, it is possible to obtain a plurality of phase shift images with a normal black-and-white camera, and thus it is possible to provide an inexpensive real grating type moire optical system. Further, since it is possible to irradiate only the light of the required wavelength band on the grating patterns 15, 16 and 17, it is advantageous to perform the work such as the visible moire fringes.

In this embodiment, as a filter switching mechanism for selectively switching the bandpass filters 25r, 25g, 25b, the bandpass filters 25r, 25g, 25b linearly arranged on the same plane are arranged. It can be configured to reciprocate by a uniaxial moving stage having a guide mechanism in a direction. In addition to this, for example, a rotary type filter structure in which fan-shaped band-pass filters are arranged on a disk may be used, and switching may be performed by a rotary operation by a rotary motor.

<Sixth Embodiment> A sixth embodiment of the present invention will be described with reference to FIGS. 14 and 15.

In this embodiment, each of the filters 12, 13, and 14 is arranged between the lattice pattern structure 11 as described above and the line sensor camera 6 which is an image pickup camera. Three band pass filters 27r, 27g, and 27b that pass the respective wavelength lights included in the respective wavelength bands corresponding to the wavelength band of
One of r, 27g and 27b is a grid pattern structure 11
A filter switching mechanism (not shown) that performs a switching operation so as to be positioned on the optical path between the line sensor camera 6 and the line sensor camera 6.
The combination including and forms a real lattice type moire optical system. With respect to this filter switching mechanism, a switching timing control unit that controls the switching timing so that the bandpass filters 27r, 27g, and 27b are positioned on the optical path between the grating pattern structure 11 and the line sensor camera 6 at different timings. 28 is provided, and the switching timing control unit 28 outputs a camera synchronization signal to the line sensor camera 6, so that the selection timing of each band filter 27 r, 27 g, 27 b and the imaging operation by the line sensor camera 6 are performed. The function of the synchronization means for synchronizing with is realized.

In such a configuration, a plurality of band filters 27r, 27g, 27b installed between the grating pattern structure 11 and the line sensor camera 6 are changed by a filter switching mechanism (see FIG. 15), and the band filters are changed. It is possible to take an image with the line sensor camera 6 at a timing different for each time 27r, 27g, or 27b, and measure the shape of the surface of the object to be inspected by each moire fringe data and the phase shift method. For example, as shown in FIG.
When the (green) bandpass filter 27g is selectively switched, the line sensor camera 6 captures only the image of the moire fringes of the wavelength G (green) that passes through the bandpass filter 27g among the moire fringes of each color. Similarly, by selectively switching the bandpass filters 27b and 27r, it is possible to acquire moire fringes having different phases by the grating patterns 15 and 16 having different heights.

Therefore, according to the present embodiment, the line sensor camera 6 takes images at different timings in synchronization with the switching of the wavelength band of the moire fringes input to the image pickup surface of the line sensor camera 6. Black and white camera 1
Since a plurality of phase-shifted moiré images can be acquired on the table, it is possible to provide an inexpensive physical lattice type moiré optical system. Further, since it is possible to dispose the switching mechanism of the bandpass filters 27r, 27g, and 27b for acquiring the moire image in the vicinity of the line sensor camera 6,
It is also possible to combine the control signals in one place.

Also in the case of the present embodiment, as the filter switching mechanism for selectively switching the band filters 27r, 27g, 27b, these band filters 27r, 27g, 27b linearly arranged on the same plane are used. It can be configured to reciprocate by a uniaxial moving stage having a guide mechanism in the arrangement direction. In addition to this, for example, a rotary type filter structure in which fan-shaped band-pass filters are arranged on a disk may be used, and switching may be performed by a rotary operation by a rotary motor.

<Seventh Embodiment> A seventh embodiment of the present invention will be described with reference to FIG.

The present embodiment corresponds to each wavelength band of the filters 12, 13, and 14 arranged between the grating pattern structure 11 and the imaging camera as described above. A band filter 29 having a beam splitter configuration that separates each wavelength light included in each wavelength band so that the wavelength light is transmitted, and an image of each wavelength light included in each wavelength band separated by the band filter 29 (a moire fringe ) Individually imaging cameras 30r, 30g, 30b
The combination including and forms a real lattice type moire optical system.

Each filter 1 of the lattice pattern structure 11
3, which are imaged by the imaging cameras 30r, 30g, and 30b for each of the light beams of a plurality of wavelengths that are absorbed by 2, 3, and 14
The shape of the surface of the object to be measured is three-dimensionally measured by the arithmetic processing by the arithmetic processing means based on the image data of the two phase-shifted moire fringes.

Therefore, according to the present embodiment, a plurality of phase-shifted moire images are simultaneously acquired by the plurality of imaging cameras 30r, 30g, 30b for acquiring the images of the respective wavelength bands forming the moire fringes. Therefore, it is possible to measure the surface profile at a higher speed, because the filter switching operation or the like is not required.

Now, the measurement of the entire surface of the cylindrical test object 4 will be described. In each of the above-described embodiments, the waviness and the dent defect generated on the surface of the cylindrical test object 4 have a height difference of a few μm level, which is difficult to detect visually.
In order to detect such defects, the inspection optical system 1 needs to have a considerably high magnification of the light receiving system.
When the magnification is high, the imaging field of view becomes narrow, the range that can be inspected at one time becomes narrow, and it becomes necessary to divide the inspection region into a plurality of portions in the axial direction and sequentially inspect each inspection region. Therefore,
More practically, as shown in FIG. 7 described above, the inspection optical system 1 is a uniaxial automatic stage 10 as a dividing direction moving mechanism having a guide mechanism 9 in the axial direction of the cylindrical object 4. When mounted on the top, and when the imaging for one round in a certain inspection area is completed, the entire inspection optical system 1 is moved to the next inspection area by the automatic stage 10, and the inspection area is imaged. By repeating such imaging and movement, it is possible to image the entire surface of the cylindrical test object 4.

Instead of moving the inspection optical system 1, the cylindrical object 4 side may be moved. In other words, a dividing direction moving mechanism for changing the relative positional relationship between the inspection optical system 1 and the cylindrical test object 4 may be provided. This can be similarly applied to any of the above-described embodiments.

Further, as shown in FIG. 17, the cylindrical object 4 to be measured is rotated by the rotary motor 8 as the sub-scanning moving means. The rotary operation (sub-scanning) by the rotary motor 8 is described above. Imaging for each of the three types of wavelength bands included in the lattice pattern structure 11 of FIG.
By synchronizing so that the measurement is performed each time, the measurement can be performed on the entire surface of the cylindrical test object 4.
This is the same in any of the above-described embodiments.

During the sub-scan, as shown in FIG.
It is also possible to obtain a plurality of phase-shifted moire fringe images by only one sub-scanning by changing the measurement wavelength band sequentially for each line light reception timing. Figure 1
8, the moire fringe 31b due to the wavelength b (blue) and the wavelength r
The state in which the moire fringe 31r due to (red) and the moire fringe 31g due to the wavelength g (green) are sequentially imaged at each line light reception timing is schematically shown.

In each of the above-described embodiments, a cylindrical test object 4 such as a photosensitive drum is measured (test object).
However, the present invention can be similarly applied to a case where a flat test object 51 such as a liquid crystal panel is used as a measurement target (test object) as shown in FIG. As the measuring method and the measuring device, any of the above-described respective embodiments can be applied.
In the illustrated example, the flat object 51 is placed on the XY automatic stage 52.
The entire surface of the planar test object 51 can be measured by the inspection optical system 1 by mounting the device on a substrate and moving it in the X and Y directions arbitrarily. However, it is also possible to mount the inspection optical system 1 on an xy automatic stage and measure the entire surface.

[0103]

According to the surface shape measuring method of the first aspect of the present invention, in the real grating type moire optical system, the grating patterns formed by the filters for absorbing the light of at least three different wavelength bands are overlapped. Conventionally, it is necessary to perform a phase shift by using a lattice pattern structure, capturing a plurality of moire fringe images formed for each light of a plurality of wavelengths to be absorbed by each filter, and applying the phase shift method. This eliminates the need for a grid pattern moving mechanism, which eliminates the time to wait for movement to acquire multiple phase-shifted moire images, shortens the measurement time, and reduces the movement of the moving mechanism. Measurement error due to accuracy can be reduced.

According to the invention described in claim 2, in realizing the invention described in claim 1, the grid pitch of each grid pattern of the grid pattern structure is set so that the contour line intervals of the moire fringes are constant. By doing so, a wider range of measurement can be performed.

According to the third aspect of the invention, in realizing the invention of the first aspect, the angle formed between the optical axis of each lattice pattern of the lattice pattern structure and the image pickup camera is made different. By setting the contour intervals of the moire fringes to be constant, it is possible to measure a wider range.

According to the invention described in claim 4, in the surface shape measuring method according to any one of claims 1 to 3, the imaging camera is a line sensor camera, and the line sensor camera is arranged in a direction orthogonal to the line direction. High-speed measurement of the radial waviness of a continuous sheet-shaped measuring object or a drum-shaped (cylindrical) measuring object by sequentially moving the relative positional relationship between the test object and the moire optical system. Is possible.

According to the surface shape measuring apparatus of the fifth aspect of the present invention, in the real grating type moire optical system, a grating pattern formed by superposing grating patterns formed by at least three types of filters that absorb light of different wavelength bands. Gratings that were conventionally required to perform phase shift by using a structure and capturing multiple Moire fringe images formed for each light of multiple wavelengths to be absorbed by each filter and applying the phase shift method. This eliminates the need for a pattern movement mechanism, which eliminates the time to wait for movement to acquire multiple phase-shifted moire images, shortens the measurement time, and reduces the movement accuracy of the movement mechanism. The measurement error can be reduced.

According to the surface profile measuring apparatus of the sixth aspect of the present invention, the lattice pattern structure having a lattice pattern having a complementary color relationship with the color filter characteristics of the color camera which is normally used is formed, so that the cost can be reduced. It is possible to provide a real lattice type moire optical system.

According to the surface profile measuring apparatus of the seventh aspect of the present invention, a plurality of light sources are turned on at different timings to obtain a plurality of phase shift images with an ordinary monochrome camera, which is an inexpensive substance. It is possible to provide a lattice type moire optical system.

According to the surface profile measuring apparatus of the eighth aspect of the invention, different timings are synchronized with changing the wavelength band of the stripes projected on the grating pattern of the grating pattern structure for a single light source. Since a plurality of phase shift images can be acquired by an ordinary black-and-white camera by capturing an image with the image capturing camera, it is possible to provide an inexpensive physical lattice type moire optical system. Further, since only the light of the required wavelength band can be irradiated onto the lattice pattern, moire fringes can be visually observed, which is advantageous for performing work such as setting.

According to the surface profile measuring apparatus of the ninth aspect of the invention, the image pickup camera takes images at different timings in synchronism with the switching of the wavelength band of the moire fringes input to the image pickup surface of the image pickup camera. Since you can obtain multiple phase-shifted moire images with one normal black and white camera,
It is possible to provide an inexpensive physical lattice type moire optical system. Further, since it is possible to dispose the band-filter switching mechanism for acquiring the moire image in the vicinity of the imaging camera, it is possible to collect the control signals in one place.

According to the surface profile measuring apparatus of the tenth aspect of the present invention, a plurality of imaging cameras for acquiring images of respective wavelength bands forming moire fringes simultaneously acquire a plurality of phase-shifted moire images. This enables high-speed measurement of the surface shape.

According to the invention of claim 11, claim 5
In the surface shape measuring apparatus according to any one of 1 to 10, the image pickup camera is a line sensor camera, and the relative positional relationship between the object to be inspected and the moire optical system is sequentially arranged in a direction orthogonal to the line direction of the line sensor camera. By moving it, it becomes possible to measure the waviness in the radial direction of a continuous sheet-shaped measuring object or a drum-shaped (cylindrical) measuring object at high speed.

According to the invention of claim 12, claim 7 is provided.
Regarding the surface profile measuring apparatus described above, the imaging camera is a line sensor camera, and the relative positional relationship between the test object and the moire optical system is sequentially moved in a direction orthogonal to the line direction of the line sensor camera, and the line sensor is also used. By emitting light sources with different emission wavelengths for each line in synchronism with the light reception timing of each line of the camera, the radial undulation of continuous sheet-shaped measurement targets or drum-shaped (cylindrical) measurement targets can be accelerated. It becomes possible to measure.

According to the invention described in claim 13, claim 8 is provided.
Regarding the surface profile measuring apparatus described above, the imaging camera is a line sensor camera, and the relative positional relationship between the test object and the moire optical system is sequentially moved in a direction orthogonal to the line direction of the line sensor camera, and the line sensor is also used. By sequentially switching the band-pass filters located on the optical path between the light source and the lattice pattern structure in synchronization with the light receiving timing of each line of the camera, a continuous sheet-shaped measurement target or a drum-shaped (cylindrical) It becomes possible to measure the waviness of the measurement target in the radial direction at high speed.

According to the invention of claim 14, claim 9 is provided.
Regarding the surface profile measuring apparatus described above, the imaging camera is a line sensor camera, and the relative positional relationship between the test object and the moire optical system is sequentially moved in a direction orthogonal to the line direction of the line sensor camera, and the line sensor is also used. By sequentially switching the band-pass filters located on the optical path between the grating pattern structure and the image pickup surface of the image pickup camera in synchronism with the light receiving timing of each line of the camera, continuous sheet-shaped measurement targets or drum-shaped (cylindrical It is possible to measure the waviness in the radial direction of the measurement target in the above-mentioned manner at high speed.

According to the invention of claim 15, claim 5
In achieving the invention described in any one of (1) to (14), the grid pitch of each grid pattern of the grid pattern structure is set so that the contour line intervals of the moire fringes become constant,
A wider range of measurements can be made.

According to the invention of claim 16, claim 5
In realizing the invention described in any one of (1) to (14), the angles formed by the optical axes of the respective lattice patterns of the lattice pattern structure and the imaging camera are made different from each other, and the contour line intervals of the moire fringes are set to be constant. As a result, a wider range of measurement can be performed.

[Brief description of drawings]

FIG. 1 is a schematic diagram for explaining the principle of a three-dimensional measurement method by a moire method as a premise of the first embodiment of the present invention.

FIG. 2 is a schematic diagram for explaining a real lattice type moire method.

FIG. 3 is an explanatory diagram for explaining a phase shift method.

FIG. 4 is an explanatory diagram showing a measurement principle on which the present embodiment is based.

FIG. 5 is a characteristic diagram showing the relationship between the stripe order N and the contour line height h _N.

FIG. 6 is a characteristic diagram showing a relationship between a fringe order N and a difference between contour line intervals Δh _N and Δh _N.

FIG. 7 is a schematic perspective view showing a configuration example of a prerequisite measurement device of the present embodiment.

FIG. 8 is a principle cross-sectional view showing a configuration example of a lattice pattern structure which is a feature of the first embodiment of the present invention.

FIG. 9 is an explanatory diagram showing the measurement principle of the second embodiment of the present invention.

FIG. 10 is an explanatory diagram showing the measurement principle of the third embodiment of the present invention.

FIG. 11 is a timing chart showing the synchronization timing.

FIG. 12 is an explanatory diagram showing the measurement principle of the fourth embodiment of the present invention.

FIG. 13 is a timing chart showing the synchronization timing.

FIG. 14 is an explanatory diagram showing the measurement principle of the fifth embodiment of the present invention.

FIG. 15 is a timing chart showing the synchronization timing.

FIG. 16 is an explanatory diagram showing the measurement principle of the sixth embodiment of the present invention.

FIG. 17 is an explanatory diagram for explaining the principle of sub-scanning.

FIG. 18 is an explanatory diagram illustrating a modified example of sub-scanning.

FIG. 19 is a schematic perspective view showing a configuration example of a measuring device when a flat test object is a measurement target.

FIG. 20 is a schematic perspective view showing a first conventional example.

FIG. 21 is a schematic perspective view showing a second conventional example.

FIG. 22 is a schematic diagram for explaining a lattice projection type moire method.

FIG. 23 is a schematic diagram for explaining a real lattice type moire method.

[Explanation of symbols]

1 Inspection optical system 2 light sources 3 lattice pattern 4 Cylindrical test object, test object 5 lenses 6 Line sensor camera, imaging camera 11 Lattice pattern structure 12-14 filters 15-17 lattice pattern 21 White light source, light source 22 Color camera, imaging camera 23r, 23g, 23b light source 24 Light emission control means 25r, 25g, 25b bandpass filter 27r, 27g, 27b bandpass filter 29 band filters 30r, 30g, 30b Imaging camera 51 Flat object, object

Continued front page    F term (reference) 2F065 AA49 AA53 BB01 BB06 DD06                       FF08 FF66 FF67 GG12 GG23                       HH06 HH12 JJ02 JJ03 JJ05                       JJ07 JJ25 JJ26 LL22 LL46                       MM03 MM04 MM07 MM28 NN01                       NN20 PP02 PP12 PP13 QQ03                       QQ31 QQ42                 5B047 AA11 AB02 BB02 BC07 BC11                       BC14 BC23 CA07

Claims (16)

[Claims] 1. A light source for generating moire fringes, a lattice pattern structure in which a plurality of lattice patterns are formed and superposed by respective filters that absorb light of at least three different wavelength bands, and moire fringes are formed. A real lattice type moire optical system having a lens for capturing an image and a light receiving system including an image capturing camera is used as an inspection optical system, and the light having a plurality of wavelengths absorbed by the filters of the lattice pattern structure is A surface shape measuring method for three-dimensionally measuring the shape of the surface of an object to be measured by arithmetic processing based on image data of at least three phase-shifted moire fringes imaged by a light receiving system. 2. The lattice pattern structure, wherein the lattice pitches of the respective lattice patterns are different from each other so that the moire fringes generated by the respective lattice patterns have the same period. The surface shape measuring method described. 3. The lattice pattern structure formed by overlapping the optical axes of the lattice patterns and the imaging camera at different angles so that the periods of the moire fringes generated by the lattice patterns are equal to each other. The surface shape measuring method according to claim 1, wherein a body is used. 4. A line sensor camera is used as the imaging camera, and the relative positional relationship between the object to be inspected and the moire optical system is sequentially moved in a direction orthogonal to the line direction of the line sensor camera. The surface shape measuring method according to any one of claims 1 to 3, wherein the shape of the surface of the test object is entirely measured. 5. A surface using a real lattice type moire optical system as an inspection optical system, which has a light source and a lattice pattern for generating moire fringes, and a light receiving system including a lens for capturing the moire fringes and an imaging camera. A shape measuring apparatus, comprising: a lattice pattern structure formed by stacking a plurality of the lattice patterns by respective filters that absorb light of at least three different wavelength bands; and the filters of the lattice pattern structure. Calculation means for three-dimensionally measuring the shape of the surface of the object to be measured by calculation processing based on the image data of at least three phase-shifted moire fringes imaged by the image pickup camera for each of the light having a plurality of wavelengths absorbed by And a surface profile measuring device comprising: 6. A surface using an actual lattice type moire optical system as an inspection optical system, which has a light source and a lattice pattern for generating moire fringes, and a light receiving system including a lens for capturing the moire fringes and an imaging camera. A shape measuring apparatus, wherein the light source is a white light source, the imaging camera is a color camera, and a plurality of the lattice patterns are formed and overlapped by respective filters that absorb light of three different wavelength bands, A grating pattern structure formed such that a wavelength band absorbed by the filter portion of each layer is equal to or more than a wavelength band passing through each color filter of the color camera, and a plurality of wavelengths absorbed by each filter of the lattice pattern structure. The surface of the object to be inspected by arithmetic processing based on the image data of the three phase-shifted moire fringes captured by the color camera for each light. Surface shape measuring apparatus comprising: a processing unit for measuring the shape three-dimensionally, the. 7. A surface using an actual lattice type moire optical system as an inspection optical system having a light source and a lattice pattern for generating moire fringes, and a light receiving system including a lens for capturing the moire fringes and an imaging camera. A shape measuring apparatus, wherein the light source is a light source having at least three types of different wavelength characteristics, light emission control means for causing these light sources to emit light at different timings, and light of different wavelength bands of each light source. A plurality of lattice patterns formed by respective filters that absorb light, and a plurality of the lattice patterns are overlapped with each other; a synchronization unit that synchronizes the light emission timing of each light source with the image capturing operation by the image capturing camera; At least three phase shifts imaged by the imaging camera for each of a plurality of wavelengths of light absorbed by the filters of the structure. Surface shape measuring apparatus comprising: a processing unit for measuring the shape of the test object surface three-dimensionally by the arithmetic processing based on the image data of the bets and the moire fringes, the. 8. A surface using an actual lattice type moire optical system as an inspection optical system, which has a light source and a lattice pattern for generating moire fringes, and a light receiving system including a lens for capturing the moire fringes and an imaging camera. A shape measuring device, comprising: a grating pattern structure formed by stacking a plurality of the grating patterns by respective filters that absorb light of at least three different wavelength bands; and the light source and the grating pattern structure. A plurality of band-pass filters that are arranged between the light sources and pass each wavelength light included in each of the wavelength bands, and a band located on the optical path between the light source and the grating pattern structure in these band-pass filters. A filter switching mechanism that sequentially switches filters; a synchronization unit that synchronizes the switching operation of each band filter and the image capturing operation of the image capturing camera; The shape of the surface of the object to be inspected is calculated by arithmetic processing based on the image data of at least three phase-shifted moire fringes imaged by the imaging camera for each light of a plurality of wavelengths absorbed by each of the filters of the child pattern structure. A surface shape measuring apparatus, comprising: an arithmetic processing unit that measures dimensionally. 9. A surface using an actual lattice type moire optical system as an inspection optical system having a light source and a lattice pattern for generating moire fringes, and a light receiving system including a lens for capturing the moire fringes and an imaging camera. A shape measuring device, comprising: a lattice pattern structure formed by stacking a plurality of the lattice patterns by respective filters that absorb light of at least three different wavelength bands; and the lattice pattern structure and the imaging camera. A plurality of bandpass filters which are disposed between the image pickup surface of the bandpass filter and a plurality of bandpass filters which pass light of the respective wavelengths included in the respective wavelength bands, and the grating pattern structure and the image pickup surface of the image pickup camera in the bandpass filters. A filter switching mechanism for sequentially switching the bandpass filters located on the optical path between them, a switching operation of each of the bandpass filters, and an imaging operation by the imaging camera A synchronizing means for synchronizing; and a calculation process based on image data of at least three phase-shifted moire fringes imaged by the imaging camera for each of a plurality of wavelengths of light absorbed by the filters of the grating pattern structure. A surface shape measuring apparatus comprising: an arithmetic processing unit that three-dimensionally measures the shape of the surface of the test object. 10. A surface using an actual lattice type moire optical system as an inspection optical system, which has a light source and a lattice pattern for generating moire fringes, and a light receiving system including a lens and an imaging camera for imaging the moire fringes. A shape measuring device, comprising: a lattice pattern structure formed by stacking a plurality of the lattice patterns by respective filters that absorb light of at least three different wavelength bands; and the lattice pattern structure and the imaging camera. A plurality of band-pass filters that are arranged between the image-capturing surfaces of the band-pass filters and pass the wavelength lights included in the respective wavelength bands; And at least three images picked up by the respective image pickup cameras for each of a plurality of wavelengths of light absorbed by the respective filters of the lattice pattern structure. Surface shape measuring apparatus comprising: a processing unit for measuring the shape of the test object surface three-dimensionally by the arithmetic processing based on the image data of the phase shifted moire fringe, the. 11. A sub-scanning moving means for sequentially moving a relative positional relationship between the object to be inspected and the moire optical system in a direction orthogonal to a line direction of the line sensor camera as the image pickup camera. The surface profile measuring apparatus according to claim 5, further comprising: 12. A sub-scanning moving means for sequentially moving the relative positional relationship between the object to be inspected and the moire optical system in a direction orthogonal to the line direction of the line sensor camera, wherein the imaging camera is a line sensor camera. 8. The surface profile measuring apparatus according to claim 7, further comprising: the synchronization unit that synchronizes with each line light reception timing of the line sensor camera to emit the light source having a different emission wavelength for each line. 13. A sub-scanning moving means for sequentially moving a relative positional relationship between the object to be inspected and the moire optical system in a direction orthogonal to a line direction of the line sensor camera as the imaging camera. 9. The surface shape according to claim 8, wherein the synchronization means sequentially switches band-pass filters located on an optical path between the light source and the grating pattern structure in synchronization with each line light reception timing of the line sensor camera. measuring device. 14. A sub-scanning moving means for sequentially moving the relative positional relationship between the object to be inspected and the moire optical system in a direction orthogonal to the line direction of the line sensor camera, wherein the imaging camera is a line sensor camera. 10. The synchronization means sequentially switches band-pass filters located on an optical path between the grating pattern structure and an imaging surface of the imaging camera in synchronization with each line light reception timing of the line sensor camera. The surface shape measuring device described. 15. The grating pitch of each of the grating patterns of the grating pattern structure is formed with different grating pitches so that the periods of Moire fringes generated by each of the grating patterns become equal. The surface shape measuring device according to any one of 1. 16. The lattice pattern structure is formed by making the angles of the optical axes of the lattice patterns and the imaging camera different from each other so that the periods of Moire fringes generated by the lattice patterns are equal. 15. The surface profile measuring device according to claim 5, wherein the surface profile measuring device is formed by overlapping and overlapping structures.