JPH07332956A - Surface shape measuring device - Google Patents

Abstract

(57) [Abstract] [Purpose] Eliminates reflections from a grating that forms Moire fringes. [Configuration] Coherent light from a light source 3 is applied to an object 8 to be measured via a grating 7. The radiated light is reflected there to form moire fringes on the grating 7. This moire fringe is imaged by the imaging camera 12, and the surface shape of the measured object 8 is measured from the imaged result. At this time, the angle of the grating 7 is appropriately adjusted so that the light reflected and diffracted by the grating 7 does not enter the imaging camera 12. Further, by rotating the polarizer 10, it is possible to distinguish and measure the reflected light from the protective cover 8b of the measured object 8 and the reflected diffracted light from the substrate 8a.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a compact disc,
The present invention relates to a surface profile measuring device for measuring the surface profile of a magneto-optical disk, a hard disk or the like having a comparatively smooth surface profile.

[0002]

2. Description of the Related Art In recent years, storage media such as optical disks capable of high-density storage have been widely used. However, in order to achieve higher-density storage of storage media, good flatness is required. It is necessary to inspect the surface shape. In order to perform this measurement, conventionally, in JP-A-3-285106 and JP-A-4-235306, the substrate surface is irradiated with a light beam, and the angle change of the reflected light is detected by the change in the shade of the image, and the swell is generated. Something to detect is proposed.

However, this method cannot be used for the purpose of measuring the surface shape because the relative value can be measured but the absolute value cannot be measured. Moire topography using a grid can be considered as a method of displaying contour lines of the surface shape, but according to this method, the interval between the contour lines is limited to several tens of μm, and the contour line increases as the distance between the grid and the measured object increases. The intervals are wide, the contour intervals on the surface are not known accurately, and it is not possible to determine whether the undulations are convex or concave. In addition, a reflective object is less likely to form moire fringes. Therefore, as a method for solving these problems, a method of using the reflection diffraction type moire phase shift is disclosed as "Substantial lattice type moire method by phase shift" in the Proceedings of the Autumn Meeting of the Precision Engineering Society (1991), p. 677. ing.

This is because a grating is arranged at a position slightly away from the object to be inspected, the object to be inspected is irradiated with light through the grating, the reflected diffracted light is detected to form moire fringes, and the grating is It is intended to detect the absolute value of the surface shape with high accuracy from the state in which the position of is moved up and down and the moire fringes change.

[0005]

However, in such a conventional apparatus, when the surface shape is measured, the reflected diffracted light on the grating surface and the image of the reflected diffracted light from the measurement surface of the object to be measured have the same optical path. There is a problem that the images are overlapped because they are incident on the image pickup camera through the through, and measurement cannot be performed. Also,
When the object to be measured has a transparent layer such as an optical disk, the reflected diffracted light on the upper surface of the transparent layer and the reflected diffracted light on the lower surface of the transparent layer enter the imaging camera through the same optical path, so the images overlap. However, there is a problem that the measurement surface cannot be measured either on the upper surface or the lower surface of the transparent layer. The present invention has been made in view of such circumstances, and eliminates reflection diffraction on the grating surface, and enables even when there is a transparent layer to independently measure the unevenness of the upper surface of the transparent layer and the lower surface of the transparent layer. It was done.

[0006]

In order to solve such a problem, the invention of claim 1 is directed to an image pickup camera for picking up moire fringes formed on a grid and a grid position with respect to a measurement surface of an object to be measured. It is composed of a calculation unit that moves multiple times in the vertical direction and calculates the amount of waviness on the measurement surface of the measured object from the output of the imaging camera obtained at that time.The grating is set to an angle at which the reflected diffracted light from it does not enter the imaging camera. It was done.
The invention according to claim 2 is a projection system for projecting parallel light onto an object to be measured, and a grating inserted between the projection system and the object to be measured.
A quarter-wave plate inserted between the grating and the object to be measured, a light receiving system for receiving moire fringes formed on the grating by being reflected from the measurement surface of the object to be measured, an imaging camera and the object to be measured. Equipped with a polarizer provided between the object and the measurement object, the grating position is moved multiple times in the direction perpendicular to the measurement surface of the object to be measured, and the amount of surface waviness of the object to be measured from the output of the imaging camera obtained at that time. It is composed of an arithmetic unit for obtaining In the invention of claim 3, a modification is inserted between the image pickup camera and the object to be measured, and the reflected diffracted light from either the upper surface or the lower surface of the transparent layer is passed through.

The invention of claim 4 is claim 1 or claim 2.
In the invention, affixed to the back surface of the transparent measured object measuring surface, having a refractive index substantially equal to the refractive index of the measured object,
It has an object that absorbs or scatters light. According to a fifth aspect of the present invention, in the first or second aspect of the present invention, the light source has a coherent length sufficiently shorter than the shortest optical distance in which interference of multiple reflection due to light occurs in the measurement system. According to a sixth aspect of the present invention, in the first or second aspect of the present invention, the grating is located at a first position and is parallel to the first position and is an odd multiple of half the grating pitch in the grating pitch direction. A grid moving means for controlling to the moved second position, and a calculation unit for taking an image of moire fringes for the first and second grid positions and performing addition or averaging processing to obtain the waviness amount of the measurement surface of the measured object. It is a thing. According to a seventh aspect of the present invention, in the first to sixth aspects of the invention, the light receiving system is provided with a slit that allows reflected diffracted light of a plurality of orders to pass therethrough. The invention of claim 8 is from claim 1 to claim 6.
In the invention of (1), the surface shape obtained by calculating the output obtained from the slit that passes the reflected diffracted light of the predetermined order to the light receiving system and the slit that passes the reflected diffracted light of the order that cannot be captured in the predetermined order are obtained. A means for synthesizing surface shapes obtained by calculating outputs is provided.

[0008]

According to the first and second aspects of the present invention, the amount of waviness is obtained because the reflected and diffracted light from the grating does not enter the imaging camera. According to the third aspect of the invention, the amount of undulation can be obtained because the reflected and diffracted light on the upper surface and the lower surface of the transparent layer can be separated. According to the invention of claim 4, the amount of undulation is obtained because the reflected diffracted light from the back surface of the transparent measurement surface of the measured object does not enter the imaging camera.
According to a fifth aspect of the present invention, moire fringes formed on a grating by a light source that emits light having a coherent length sufficiently shorter than the shortest interference distance at which multiple reflections by light occur, and the grating position is measured with respect to the measurement surface of the object to be measured. It is possible to eliminate the unevenness of light due to interference by taking an image with the imaging camera while moving it in the vertical direction multiple times and performing a predetermined calculation based on the output of the imaging camera obtained at that time. Desired.

According to a sixth aspect of the present invention, the lattice has a first position,
Grating moving means for controlling to a second position which is parallel to the first position and is moved by an odd multiple of half the grating pitch in the pitch direction of the grating, and moire for the first and second grating positions. By taking an image of the stripes and adding or averaging it to obtain the amount of undulations on the measured surface of the measured object, the pattern on the measured surface of the measured object and the effect of light unevenness can be removed. The amount of swell is required. According to a seventh aspect of the invention, in the first to sixth aspects of the invention, the entire measurement surface of the object to be measured can be photographed by an imaging camera with light obtained from a slit that passes through the multiple-order reflected diffracted light provided in the light receiving system. Because it is possible, the amount of swell is required. According to an eighth aspect of the present invention, in the first to sixth aspects of the invention, the surface shape of a part of the measured surface of the object to be measured is obtained by the light obtained from the slit that passes the reflected diffracted light of a predetermined order provided in the light receiving system, Furthermore, the surface shape of the other part of the measured object is obtained by the light obtained from the slit that passes the reflected diffracted light of the order that cannot be captured in the predetermined order, and by combining the different surface shapes, the measured surface of the measured object is measured. The total swell amount is required.

[0010]

1 is a diagram showing a first embodiment of the present invention, which is suitable for measuring the shape of a comparatively smooth surface of a hard disk or the like. The light source 3 is designed to output a monochromatic point light such as a helium neon laser,
It is output via the light projecting system 1. The light projecting system 1 passes through a condenser lens 4 and a spatial filter 5, and a condenser lens 6 projects a parallel light beam having a predetermined area. The projected light passes through the grating 7 having a predetermined angle with the light beam, and is projected onto the measurement surface 8a of the measured object 8 such as a hard disk to form a shadow of the grating 7.
As will be described later, the grid 7 is provided on the measurement surface 8 of the measured object 8.
The angle is set so as not to be parallel to a.

The light reflected by the measurement surface 8a of the object 8 to be measured forms a shadow in the shape of a lattice, but the light containing the shadow again forms the lattice 7 again.
Is overlaid with. At this time, the superposed light includes surface shape information of the measurement surface 8a of the object 8 to be measured, forms moire fringes of contour lines according to the unevenness of the surface, and is imaged by the imaging camera 12 via the light receiving system 2. It At this time, it is necessary to set a predetermined angle so that the reflected diffracted light from the grating 7 does not enter the imaging camera 12.

The light receiving system 2 has a lens 9 for receiving incident light and a vicinity of a focal plane of the lens 9 for selecting diffracted light of a desired order that is emitted when the reflected light from the measurement surface 8a of the object 8 to be measured passes through the grating. It is composed of a slit 11 provided in the. Then, an image pickup camera 12 such as a CCD camera is provided at a position where a desired measurement range can be photographed on the measurement surface 8a of the object to be measured 8, and the output thereof is taken into a storage element such as an image memory (not shown).

Next, in the height direction of the grating 7, that is, in the direction perpendicular to the surface of the measurement surface 8a of the object 8 to be measured, 1/4 of the interval between the contour lines of the moire fringes (phase π / 2 shown in FIG. 2). (Corresponding to)) on the stage such as a piezo actuator, and similarly, the intensity signal of the imaging camera 12 is taken into the storage element. This operation is shown in FIG. 2 as “0” “π / 2” “π”
By repeating up to “3π / 2”, a total of four images are obtained, and the calculation unit 13 performs the next calculation to output the amount of waviness.

As shown in FIG. 2, the light intensity of a point (X, Y) on the measurement surface 8a of the object 8 to be measured is I (X, Y), where a is a stripe bias, b is a modulation component, and h is Distance to lattice plane, Δ
Let h be the height from one contour line to the next contour line. I (X, Y) = a (X, Y) + b (X, Y) cos (2πh / Δh + φ) (1)

Here, the phase φ in the cosine is 0, π /
The intensity signals stored in the four kinds are stored in I0 (X, Y), I1 (X, Y) and I, respectively.
Assuming 2 (X, Y) and I3 (X, Y), the result is as follows. I0 (X, Y) = a (X, Y) + b (X, Y) cos (2πh / Δh) ... (2) I1 (X, Y) = a (X, Y) + b (X, Y) ) Cos (2πh / Δh + π / 2) = a (X, Y) -b (X, Y) sin (2πh / Δh) ... (3) I2 (X, Y) = a (X, Y) + b (X, Y) cos (2πh / Δh + π) = a (X, Y) -b (X, Y) cos (2πh / Δh) ... (4) I3 (X, Y) = a (X, Y) ) + B (X, Y) cos (2πh / Δh + 3π / 2) = a (X, Y) + b (X, Y) sin (2πh / Δh) (5) From this, the absolute amount of swell h (X) , Y) is calculated as follows. h = Δh / 2πtan ^-1 ((I4-I1) / (I0-I2)) ... (6)

As described above, the undulation result can be output without being affected by the bias a and the modulation component b. In this configuration, by arranging the surface of the grating 7 so as not to be parallel to the measuring surface 8a of the measured object 8, the reflected diffracted light of the grating surface 7 and the reflected diffracted light from the measuring surface 8a of the measured object 8 and the optical path thereof. The slit 11 blocks the diffracted light reflected from the grating and is not projected onto the imaging camera 12. FIG. 8 shows the result of measuring the surface shape of the silicon substrate according to the above-mentioned embodiment. Further, as shown in FIG. 3, when the measured object 8 has a protective transparent layer on the data recording surface such as an optical disk, the transparent layer from the upper surface 8a of the transparent layer and the lower surface 8b on the data recording surface side is Since the reflected and diffracted light has different polarization states, the light receiving system 2 is provided with the polarizer 10, and
By rotating 0, the reflected diffracted light can be separated, and the undulations of the optical disk transparent layer upper surface 8a and the transparent layer lower surface 8b corresponding to the data recording surface can be measured independently.

In order to increase the efficiency of separating light by polarized light, it suffices that the light irradiated on the measurement surface 8a of the object 8 to be measured is linearly polarized. Although a helium neon laser is used as the light source 3, any light source capable of emitting parallel light may be used. In the light projecting system 1, the condenser lens 4, the spatial filter 5, and the condenser lens 6 are desired. A mirror or the like may be used as long as it can uniformly irradiate a parallel light beam, and the configuration is not limited. The amount of movement in the height direction of the lattice and the number of memory fetches are not limited to the examples,
Other combinations may be used as long as h (X, Y) can be calculated. FIG. 4 shows a second embodiment in which reflected and diffracted light from the grating is blocked. When the quarter-wave plate 18 is inserted between the grating 7 and the object to be measured 8 and linearly polarized light is emitted, the grating 7
The polarized state of the reflected diffracted light from is maintained and the measured object 8
The diffracted light reflected from the measurement surface 8a of 1 is different from the polarization angle of the diffracted light reflected from the grating 7 by about 90 degrees due to the quarter-wave plate 18.

Therefore, when the polarization filter 10 is provided in the light receiving system 2 so as to pass the light in the polarization direction substantially perpendicular to the polarization angle of the reflected light from the grating 7, the reflected diffracted light from the grating 7 is not passed and the object to be measured is not passed. Only reflected and diffracted light from 8 can pass. In this example, the grating 7 may be parallel to the measurement surface 8a of the measured object 8. FIG. 5 is an example of measuring the measurement surface shape when the measured object 8 is a transparent object such as glass. In this case, since the back surface of the measured object 8 with respect to the measurement surface 8a is in contact with the atmosphere, reflection occurs due to the difference in the refractive index at that portion, and the images of the front surface reflection and the back surface reflection are overlapped, which makes measurement difficult. For this reason, a light absorber 16 is attached to the back surface of the measured object 8 to absorb the light, the refractive index of light of which is substantially the same as that of the measured object 8. The difference from FIG. 1 is that an object 16 having a light refractive index substantially equal to that of the measured object 8 is attached to the back surface of the measurement surface 8a of the measured object 8. With such a configuration, the light incident on the imaging camera 12 is only the reflected and diffracted light from the measurement surface 8a of the measured object 8, which facilitates the measurement. In order to absorb light, it can be realized by a method of adding a black pigment to a flexible substance. Further, the light absorber 16 may be an object that scatters light.
An example of the light absorber 16 is “2253” manufactured by 3M.
"strip coating". Further, in order to remove the reflected diffracted light from the grating, either the first embodiment or the second embodiment may be used.

When the coherent length of the light source is long, interference occurs due to multiple reflection on each surface of the optical system, and interference fringes other than the contour fringes are observed on the imaging camera. As a result, the signal strength may become extremely small locally, which may reduce the measurement accuracy or make the measurement difficult. However, if the coherent length of the light source is made shorter than the shortest optical distance in which multiple reflection occurs, interference does not occur. For example, the refractive index n = 1.5,
The optical distance L in the case where the thickness t is 1 mm and the incident angle θ from the light source 3 to the measurement surface 8a of the measured object 8 is 45 degrees is calculated as follows. L = 2t · n / cos θ = 4.24 (mm) (7) When this distance is shorter than the optical distance of multiple reflection in the lens of the optical system or in other parts, the coherent length is 4. 24m
If the light source is shorter than m, interference does not occur and measurement accuracy is not affected. As a light source having a short coherence length, there are a multimode semiconductor laser, an SLD (super luminescence diode), and the like. The coherent length is preferably as short as it is monochromatic, and a sodium lamp or a mercury lamp, which is an incoherent light source, may be combined with a filter that passes only a specific bright line spectrum. Further, in order to remove the reflected and diffracted light from the grating, either the structure according to the first embodiment or the structure according to the second embodiment may be used.

Of the object 8 to be measured having the front surface 8a and the back surface 8b in the example of FIG. 6, the measurement surface 8a on the front surface side is printed or coated, and the pattern thereof is the grid 7
When the spatial frequency is close to, these patterns and unevenness
And cause interference with the measurement. Grid 7 here
Is assumed to have a sinusoidal transmission intensity distribution, and A
Let (X, Y) be the bias of the grating transmission intensity, B (X, Y) be the modulation component, and p be the grating pitch, and the transmission intensity distribution thereof is defined as follows. Ia (X, Y) = A (X, Y) + B (X, Y) sin (2πX / p) (8) A component having the spatial frequency closest to the grating 7 on the measurement surface 8a of the measurement object 8. The intensity distribution of the pattern is defined as follows. Ib (X, Y) = C (X, Y) + D (X, Y) sin {2πX / (p + Δp) + ζ} ・ ・ ・ (9) As a result, due to the superposition of the lattice 7 and the pattern, Moire fringes having an intensity distribution such as and unrelated to contour fringes are observed. Ia (X, Y) Ib (X, Y) = A (X, Y) C (X, Y) + A (X, Y) D (X, Y) sin {2πX / (p + Δp) + ζ} + B (X, Y) C (X, Y) sin (2πX / p) + {B (X, Y) D (X, Y) / 2} sin {2πX (2p + Δp) / (p + Δp) + ζ} (10)

The second and third terms of the equation (9) can be ignored because the frequencies are high, and the equation (10) is as follows. Ia (X, Y) Ib (X, Y) = α (X, Y) + β (X, Y) sin {2πX (2p + Δp) / (p + Δp) + ζ} ・ ・ ・ (11) , Α (X, Y) = A (X, Y) C (X, Y), β (X, Y) = B (X, Y) D (X, Y) / 2
And Therefore, the beats of the spatial frequency of the pattern and the spatial frequency of the lattice 7 are observed. That is, the equation (1) is as follows. I (X, Y) = a (X, Y) + b (X, Y) cos (2πh / Δh + φ) + α (X, Y) + β (X, Y) sin {2πX (2p + Δp) / (p + Δp) + ζ} (12)

Now, in this state, when φ in the equation (12) is shifted by 2π and the grating is seen from the light receiving system 2 side in FIG. 6, ζ is π.
Just move. When the measurement surface 8a of the measured object 8 is thus patterned, the phase φ is shifted as shown in the equations (2) to (5), and the equation (6) is calculated.
The fourth term of the equation (12) remains without disappearing and affects the measurement accuracy. Therefore, every time data of each screen is captured, it is parallel to the lattice plane and is an odd multiple of p / 2 in the lattice pitch direction, that is, ζ is (2n + 1) π (where n = 0, ± 1, ± 2, ± 3
...) and moving or averaging to obtain formula (12)
The fourth term of is canceled and the error term disappears. A method such as a piezo actuator or a stepping motor may be used to move the grid. Further, in order to remove the reflected and diffracted light from the grating, either the structure according to the first embodiment or the structure according to the second embodiment may be used.

Only the reflected diffracted light of a specific order is slit 1.
When selected and transmitted through 1, the slit 11 surface is shown in FIG.
The reflected diffracted light from the measurement surface 8a of the measured object 8 as shown in (a) is observed. When the undulation of the measurement surface 8a is extremely large, a part of the diffracted light reflected and diffracted from the measurement surface 8a does not pass through the slit 11 and an unmeasurable portion appears.
Therefore, the slit 11 is formed into a shape as shown in FIG. 7B through which the reflected and diffracted lights of a plurality of orders pass. The larger the waviness of the measurement surface 8a, the more the diffracted light needs to be captured, in which case a measurement error occurs. The measurement error δh is as follows. δh = p (tan θ-tan θm) / 2 (13) where θm is as shown below. sin θm = sin θ + m λ / p where m is the order of diffracted light to be transmitted, λ is the wavelength of the light source, and p
Is the pitch of the grid.

Now, suppose that θ = 45 degrees, p = 100 μm, λ
= 633 nm and m = 2 (m is the diffraction order). m = 2
Is a large circle (m in the center of the slit 11 of FIG.
Slit 1 for passing from the (diffracted light of = 0) to the second circle (diffracted light) written m = 2 and m = -2 on the left and right
1 and its structural example is shown in FIG. The error in that case is δh = 1.77 μm from the equation (13),
It is a level that can be ignored for a measurement surface with a large undulation. It should be noted that the slit 11 may have any shape as long as it can pass a plurality of orders and unnecessary light such as reflected and diffracted light from the grating does not enter the imaging camera 12.

When the undulation amount of the measured surface 8a of the object 8 to be measured is large in the slit shape as shown in FIG. 7 (a),
A part of the reflected and diffracted light from the measurement surface 8a is not projected on the imaging camera 12, and a part that cannot be measured appears. Therefore, of the reflected diffracted light from the measurement surface 8a, only the reflected diffracted light of the order that can pass through the slit 11 is taken out by the slit 11, and the information on the surface shape of a part of the measured surface 8a is taken in.
Calculate. Next, the slit 11 is moved, and the information of the surface shape of the portion of the measurement surface 8a that cannot be captured last time is fetched and the calculation is performed. Then, they are combined to measure a portion over a wide area. By doing so, even if the undulation is large, the measurement can be performed and no error occurs.

[0026]

As described above, the invention of claim 1 has an effect that the reflected diffracted light from the grating does not interfere with the measurement because the reflected diffracted light from the grating is set to an angle at which it does not enter the imaging camera. . In the invention of claim 2, since the quarter-wave plate is inserted between the grating and the object to be measured 8 and the polarizer is inserted between the grating and the imaging camera, the object to be measured 8 is measured.
Since only the reflected diffracted light from the measurement surface 8a is imaged by the imaging camera and the reflected diffracted light from the grating is not imaged, it has an effect of not affecting the measurement. The invention of claim 3 is
In the invention of claim 1, when the measured object 8 has a transparent layer on the data recording surface, by rotating a polarizer provided between the imaging camera and the measured object 8, either the upper surface or the lower surface of the transparent layer can be rotated. Only the reflected and diffracted light from one side can be passed, and the undulations on the upper surface and the lower surface of the transparent layer can be measured independently.

The invention of claim 4 is claim 1 or claim 2.
In the invention, since an object having a refractive index substantially equal to that of the measured object 8 and absorbing or scattering light is attached to the back surface of the measured surface 8a of the measured object 8, the back surface of the measured object 8 is The effect is that reflection can be prevented. According to the invention of claim 5, in the invention of claim 1 or claim 2,
By having a light source with a sufficiently short coherence length,
There is an effect that unevenness of light due to multiple reflection interference of an object in the measurement system can be removed and the measurement can be prevented from being disturbed.

The invention of claim 6 is claim 1 or claim 2.
In the invention of claim 1, the grating is moved to a first position and to a second position which is parallel to the first position and is moved in the pitch direction of the grating by an odd multiple of half the pitch of the grating, Since the amount of waviness of the measurement surface 8a of the measured object 8 is measured by a signal obtained by adding or averaging the image pickup outputs of No. 1, even if the measured object 8 has characters or patterns printed on it, there is uneven light source. Also has the effect that the measurement result is not hindered. According to the invention of claim 7, in the invention of claims 1 to 6, since the light receiving system is provided with a slit for allowing the reflected and diffracted light of a plurality of orders to pass therethrough, even if the measurement surface 8a of the measured object 8 has a large undulation amount, It has an effect that the result can be measured. The invention according to claim 8 is the invention according to any one of claims 1 to 6, in which the surface shape obtained by calculating the output obtained from the slit for passing the reflected diffracted light of a predetermined order into the light receiving system and the predetermined order cannot be captured. Since the means for synthesizing the surface shape obtained by calculating the output obtained from the slit that passes the reflected diffracted light of the different order is provided, the measurement surface 8a of the measured object 8 is provided.
Even if the amount of waviness is large, there is an effect that the result can be measured.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an exemplary embodiment of the present invention.

FIG. 2 is a diagram illustrating a movement amount of a grid.

FIG. 3 is a diagram showing a configuration of another embodiment.

FIG. 4 is a diagram showing a configuration of another embodiment.

FIG. 5 is a diagram showing a configuration of another embodiment.

FIG. 6 is a diagram showing a configuration of another embodiment.

FIG. 7 is a diagram showing a configuration of another embodiment.

FIG. 8 is a diagram showing an example of measurement results.

[Explanation of symbols]

1 ... Projection system, 2 ... Light receiving system, 3 ... Light source, 4, 6, 9 ... Lens, 5 ... Pinhole, 7 ... Lattice, 8 ... Object to be measured 8, 1
0 ... Polarizer, 11 ... Slit, 12 ... Imaging camera, 13
... arithmetic unit, 16 ... light absorber, 18 ... quarter wave plate

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Toru Yoshizawa 1-19-5 Shinmachi, Fuchu-shi, Tokyo 102 of 1 Fuchu Second House

Claims (8)

[Claims] 1. A projection system for projecting parallel light onto an object to be measured, a grating inserted between the projection system and the object to be measured, and a moire formed on the grating by being reflected from a measurement surface of the object to be measured. A light receiving system for receiving stripes, an imaging camera for imaging the output of the light receiving system, and moving the grid position a plurality of times in the vertical direction with respect to the measurement surface of the object to be measured, based on the imaging camera output obtained at that time. Surface shape characterized in that the grating is set to an angle at which reflected diffracted light from the grating does not enter the imaging camera. measuring device. 2. A projection system for projecting parallel light onto an object to be measured, a grating inserted between the projection system and the object to be measured, and a quadrant inserted between the grating and the object to be measured. 1 wavelength plate, a light receiving system that receives the moire fringes reflected on the measurement surface of the object to be measured and formed on the grating, an imaging camera that images the output of the light receiving system, the imaging camera and the object to be measured Between the polarizer provided between and the grating position is moved a plurality of times in the direction perpendicular to the measurement surface of the object to be measured, and the predetermined calculation is performed based on the output of the imaging camera obtained at that time. A surface profile measuring apparatus comprising: a calculation unit that obtains a flatness of a measurement surface. 3. The object to be measured has a transparent layer on a data recording surface, and a polarizer is provided between the imaging camera and the object to be measured, and the polarizer is the transparent layer. A surface profile measuring apparatus, which allows only reflected and diffracted light from either the upper surface or the lower surface thereof to pass therethrough. 4. The method according to claim 1, which is attached to the back surface of the transparent measurement surface of the measured object and has a refractive index substantially equal to the refractive index of the measured object and absorbs or scatters light. A surface profile measuring device comprising an object. 5. The surface profile according to claim 1 or 2, wherein the coherent length of the light source is sufficiently shorter than the optical distance of the shortest interference in which multiple reflections of light occur in the measurement system. measuring device. 6. The grating according to claim 1 or 2, wherein a grid is provided at a first position, and the grid pitch is parallel to a plane of the grid with respect to the first position in the pitch direction of the grid. Grating moving means for controlling to a second position moved by an odd number of half, and moire fringes for the first and second grating positions are imaged and added or averaged to determine the amount of waviness of the measured surface of the object to be measured. A surface shape measuring apparatus comprising a calculating unit for obtaining. 7. The surface profile measuring device according to claim 1, wherein the light receiving system is provided with a slit for passing a plurality of orders of reflected and diffracted light from the measurement surface of the object to be measured. . 8. The slit according to claim 1, wherein the light receiving system has a slit placed at a first position for allowing reflected light of a predetermined order from the measurement surface of the object to be measured to pass through the light receiving system; And a moving means for moving the slit to a second position so as to pass the reflected diffracted light of the order that cannot be passed by the order, and is calculated by the reflected diffracted light obtained from the slit placed at the first position. And a synthesizing means for synthesizing the surface shape of the measurement surface of the object to be measured and the surface shape of the object surface to be measured obtained from the reflected diffracted light passing through the slit placed at the second position. A surface shape measuring device characterized by being provided.