JPS60201204A - Measuring instrument for surface property - Google Patents

Abstract

PURPOSE:To improve precision by processing regular reflection intensity, the quantity of total reflection, and incident light intensity when pieces of luminous flux with the same wavelength are projected on a surface to be measured at angles of incidence satisfying specific expressions, and obtaining surface roughness information. CONSTITUTION:Pieces of luminous flux having the same wavelength are projected on the surface to be measured at angles theta1 and theta2 of incidence from light projecting means 2A and 2B respectively. In this case, theta1 and theta2 are so set that expressions hold, where lambda is the wavelength of the luminous flux and sigma is the dispersion of the height distribution of the profile of the surface to be measured. The pieces of incident luminous flux are guided out partially to detect light intensity proportional to the incident light intensity by the 2nd photodetecting means 6A and 6B. Regular reflection intensity and the quantity of total reflection corresponding to each piece of incident luminous flux is obtained by the 1st photodetecting means 8A and 8B. Then, a divider 12 divides the regular reflection intensity signal by the corresponding incident light intensity or quantity of total reflection and an arithmetic output device 13 calculates and outputs amplitude information and tilt angle information or frequency information.

Description

DETAILED DESCRIPTION OF THE INVENTION Jin's invention relates to an apparatus for measuring the surface properties of various objects, particularly properties related to surface roughness.

In general, the surface roughness of various substances is deeply related not only to the aesthetic appearance of the surface but also to the mechanical properties and surface physical properties of the substance. For example, in the field of steel, the surface roughness of the steel sheet product is closely related to the aesthetics such as surface gloss, as well as press workability, painting performance, plating performance, etc. Surface roughness control has become an extremely important issue. However, conventional surface roughness measurement devices and surface roughness display methods are still insufficient for truly optimal roughness control. In other words, regarding the surface texture, Ra, which is information about unevenness,
(center line average roughness), Rmax (maximum roughness), PP
I (peak per 1nch) is only determined, which is insufficient as information on complex surface properties, that is, rough surfaces with irregularly changing irregularities and slopes. Regarding measuring devices, the most common conventional one is a stylus-type roughness meter, but this roughness meter can only measure a small part of the surface being measured, and cannot provide information about the properties of the entire surface. Furthermore, since it is a contact measurement, it is difficult to measure at high speed, mechanical failures are likely to occur, and the surface to be measured may be damaged.

Recently, methods have been proposed for measuring statistical properties regarding surface roughness information of cine regular surfaces using optical methods. In other words, the parameters representing surface roughness are:
Various indexes are used, such as average roughness, average inclination angle, and average peak spacing, but these are broadly classified into amplitude information, inclination angle information, and frequency information of the surface profile, and are usually based on statistical properties of irregular surfaces. It is known that the information on the surface profile can be expressed by two of these types of information, and a method for optically obtaining surface profile information from this point of view was proposed in Japanese Patent Publication No. 53-46460.
The method shown in the publication and Japanese Patent Application Laid-Open No. 54-24051
The method shown in the above publication has already been proposed. In the former method, two beams of light with different wavelengths are projected onto the surface to be measured, and the information is obtained from the half-width of light diffusion. Two different types of light sources are required, and when a laser is used as the light source, there is a problem that no suitable light source currently exists, and disadvantages include the complicated device configuration and maintenance, and the high price. There is. On the other hand, the latter method obtains the information by projecting a beam of the same wavelength onto the surface to be measured at two different incident angles for convenience in equipment implementation), and eliminates the drawbacks of the former method. Is possible. However, when designing and realizing an actual device based on the latter method, there are the following drawbacks or inadequacies.

First of all, the setting conditions regarding the wavelength of the light beam projected onto the surface to be measured, the angle of incidence, and the roughness range of the surface to be measured are unknown. In some cases, the variation in the values can become extremely large. Second, when applied directly to an actual device, differences in total reflectance of the surface to be measured, fluctuations in light source intensity,
In addition, when the object to be measured is moving, vibrations on the surface to be measured may cause measurement errors, making it impossible to obtain a sufficient measurement density, so it is desirable to correct for these error factors. However, the method is not specifically shown. For these reasons, the above-mentioned Japanese Patent Application Laid-Open No. 54-2405
When the method disclosed in Publication No. 1 is implemented as an actual device, it is not possible to obtain a satisfactory measurement accuracy.

On the other hand, in normal optical roughness measurement, variations in the total reflectance of the surface to be measured due to surface impurities, etc. are simply treated as a measurement error factor and subject to correction. If used effectively, the presence or absence of surface deposits,
It is possible to obtain information regarding the type, etc., which is extremely effective in terms of surface quality control.

The present invention was made against the background of the above-mentioned circumstances, and it solves the above-mentioned problems in embodying the method shown in the above-mentioned Japanese Patent Application Laid-Open No. 54-24051 as an apparatus.
The basic objective is to provide a surface texture measuring device that can always obtain surface roughness information with high accuracy. A second object of the present invention is to provide a surface texture measuring device that can obtain surface roughness information and information about surface deposits at the same time.

In other words, the first invention of the present application separates the luminous flux of the same wavelength into two different
To measure amplitude information and tilt angle information, which are two independent pieces of information about surface roughness, each incident angle is set to the roughness range (σ) and the wavelength. At the same time, the detected value is corrected for error factors such as differences in total reflectance of the surface to be measured, fluctuations in light source intensity, or vibrations of the surface to be measured, thereby achieving high accuracy. The present invention provides a surface texture measuring device capable of obtaining the above information. Further, the second invention of the present application focuses on the fact that surface deposits on the surface to be measured affect the reflectance of the surface to be measured, and causes the apparatus of the first invention to further output information regarding the surface deposits. Provide devices with added functions.

Specifically, the surface texture measuring device of the first invention determines the surface texture of the surface to be measured based on the intensity of reflected light obtained by projecting light beams of the same wavelength (two beams) onto the surface to be measured at two different incident angles. In a device that records amplitude information and inclination angle information or frequency information of a profile; the wavelength of the light beam is λ, the height of the profile on the surface to be measured, the dispersion of the distribution is σ, and the two incident angles are θ0. As θ2, the incident angle θ8. A light projection means with θ2 set; each incident angle 0. ．． a first light detection means for detecting the specular reflection intensity and the total reflection amount respectively corresponding to the incident light flux of θ2; a second light detection means; a signal processing device that generates an incident light intensity signal, a specular reflection intensity signal, and a total reflection amount signal corresponding to each incident light beam based on the output of each of the light detection means; specular reflection intensity; A divider that divides a signal by a corresponding incident light intensity signal or total reflection amount signal; and a calculation output device that calculates and outputs amplitude information and tilt angle information or frequency information from the output of the divider. It is characterized by:

In addition, the surface texture measuring device of the second invention has the function of dividing the specular reflection intensity signal by the corresponding incident light intensity signal or total reflection amount signal in the divider in the device of the first invention as described above. A function is provided to divide the quantity signal by a corresponding incident light intensity signal, and the calculation output device calculates and outputs amplitude information, tilt angle information or frequency information, and information regarding surface deposits from the output of the divider. It is characterized by the fact that

The surface texture measuring device of the present invention will be explained in detail below.

First, the basic principle of the measuring device of the present invention will be explained based on experimental results by the inventors.

The amplitude information of the roughness parameter is the variance σ of the height distribution of the surface profile, and the frequency information is the autocorrelation function l/e.
If a distance T that decreases to (hereinafter referred to as an autocorrelation distance) T is selected, the tilt angle information is expressed by σ7. In the apparatus of the present invention, the amplitude information σ and the tilt angle information φ are determined based on the following principle.

When the wavelength of the projected light projected onto the surface to be measured is λ and the angle of incidence is θ, the intensity of the specular reflection light, and the roughness parameters σ, σ
The relationship with force is based on Beckmann's theory (note), P. Beckmann et al., “The Sc.
atlingof Electromagnetic W
aves from Rough SurfacesJ
Pergamon Press, published in 1963), g = (4πσ/λ・cosθ)...
・If defined as (1), if g < 1, I, = f, (σ) ・・・・・・(
2) When g>to 11B = f 2 ('/'r)
--(3) holds true.

The invention disclosed in the above-mentioned Japanese Patent Publication No. 53-46460 is based on the same Beckmann theory, and the invention disclosed in Japanese Patent Application Laid-open No. 54-24051 is based on the above formula (2). Although the condition holds true even when g=1 is used, the quantitatively strict conditions have not been clarified, and the measurement accuracy when these relationships are used is also unknown.

In contrast, in this invention, based on detailed theoretical and experimental studies, it is assumed that T = approximately 20 to 100 μm for rough surfaces that are usually measured (e.g., cold rolled steel plates, aluminum plates, etc.). We derived the following results.

When g≦4, I, = f, (σ) ・・・・・・(4
) If g≧10, I, = r2(σ/'r) −
・・・・(5) The basis for such equation (4) # (5) to hold is as follows.

I, toa (~q), oyohir, toafi (oc
Figures 1 and 2 show the results of numerical calculations regarding the relationship JT/T) based on Beckmann's theory. As shown in Fig. 1, when the value of n("σ) is small, the value of 〉 corresponds uniquely to 47(■σ) regardless of the value of T (within the range of too-too μm). Then, Ji: If (ocσ) becomes large, the value of T becomes larger, and Jii for the value of
The value of ("σ) fluctuates. That is, as the value of i7("σ) increases, the variation when subtracting the value of 6(ocσ) from the value of I8 increases. In Figure 1, ε indicates the error that occurs when calculating the value of Jii ("σ) from the value of
The conditions under which the value of σ(” −/ir ) can be obtained with % or less are as follows.
It can be seen that 9≦2, that is, g≦4. Therefore, equation (4) holds true under the condition of g≦4. On the other hand, from Figure 2, we can see that
T) For Tono rJA section 1c, the value of T is 20~
4γT(
It can be seen that the variation in ocσ/T ) becomes negligibly small when g≧10. In other words, when g≧10, I8 becomes σ/'r ("v'r/T)
Therefore, under the condition of g≧10, the above formula (5) holds true.

Regarding equation (5) above, in the case of g) 100, under actual measurement conditions, the variation in σl with respect to the measured value of Is is extremely large, and actual measurement may become impossible. An example of this is shown in FIGS. 3 and 4 for a cold-rolled steel dull material with σ of 0.6 to 3.0 μm.

In the example in Figure 3, the incident wavelength λ = 0.514 μm1 the incident angle θ
= 100, and g) I' measured for the case of 100
The relationship between the value of s and σ measured with a stylus roughness meter is shown. In the example of FIG. 4, the incident wavelength λ=3.39 μm, the incident angle θ=100, and 10≦g≦ioo.

There are some people who show the relationship between the value of ■5 measured for the case and the value of σ force measured with a stylus roughness meter.
It can be seen that in the case of 0≦g≦lOO, the degree of correlation between IS and σ/T is high, whereas in the case of g) 100 in FIG. 3, the variation is extremely large.

The reason for this is that the values of σ and T used as true values were obtained using the stylus roughness meter as described above, and the contribution to σ and T that cannot be detected with the stylus It is presumed that this is because a surface unevenness component with a small amplitude affects light reflection, or because there is variation in the autocorrelation function form of the surface pull-fill, which increases as g increases. Therefore, the condition for the above-mentioned formula (5) to hold is not simply defined as g≧10, but also needs to be defined as 10≦g≦100.

That is, when lO≦g≦100, I, = −r2 (σ/II')
...It is necessary to do (6).

For the above reasons, the projection light that can obtain the amplitude information σ with high precision should be the wavelength λ, the incident angle θ, (4πφ・cosθ,)≦4 (4πφ・cosθ,)≦4 (The projection light that satisfies η and obtains the tilt angle information σ, etc. with high accuracy is based on the conditions for the above equation (6). The wavelength λ and the incident angle θ2 are 10≦(4πσ/λ”Cog 02 )≦too...
...-(8) must be satisfied. Therefore, in the apparatus of this invention, two wavelengths of the same wavelength λ with respect to the measured surface are
Incident angle θ1 of the book's projected light flux. The light projection means including the light source is set so that θ2 satisfies the above-mentioned equations (7) and (8) according to the wavelength λ and the roughness range (σ).

On the other hand, the light detecting means of the optical system in the apparatus of the present invention uses specular reflection intensity 18
1, 1.2 and total reflection amount Σ1. one or more detectors as a first light detection means for detecting Σ8, and a light intensity I that is a part of the two incident light beams and is proportional to each of them.
01. The configuration includes an optical system and a photodetector as a second photodetection means for detecting IO. In addition, the code X3 is ζ.

I :Σ Σ :V,, the suffix of I is 82
l# 2 91 02 Incident angle θ1. It is assumed that this corresponds to the suffix of θ2. I, , I, □ and Σ1. As photodetectors for detecting Σ2, separate ones may be used for μ and φ, respectively.
A common detector may be configured to detect several intensities; for example, in the simplest example, one detector is scanned around the circumference of the measured point to obtain a series of light intensity distributions. Me, I
, I81 82 e Σ1. A mechanism for adding Σ2 can be considered.

FIG. 5 shows the principle of an example of the optical system in the measuring device of the present invention, which includes the above-described light projection means and light detection means.

In FIG. 5, laser beams IA, I with the same wavelength λ
The laser light sources 2A and 2B that generate the light B are incident at angles of incidence θ8, 0, . It is arranged so that the laser beams IA and IB are incident on -
Ru. Also, a laser light source 2A.

A part of the laser beams IA and IB emitted from 2B are
The beams are guided by the beam splitters 5A, 5B to the photodetectors 6A, 6B as second photodetecting means, whereby the incident angle θ1. Light intensity I01 e ” which is proportional to the light intensity of the incident light flux (laser beams IA, IB) at θ2
03 is detected. On the other hand, the laser beam projected onto the surface to be measured 3 is reflected at the point to be measured 4, producing light reflection intensity distributions 7A and 7B, respectively. And its light reflection intensity distribution 7A
, 7B are detected by photodetectors 8A and 8B as second photodetection means made of silicon photodiodes or the like. That is, these photodetectors 8A and 811 scan an arc centered on the point to be measured (light reflection point) 4, and set the incident angle θ1. Light reflection intensity distribution 7 corresponding to each of θ2
Detect A and 7B. In this example, the specular reflection intensity I3° for the light beam at the incident angle θ1 is determined by the photodetector 8A.
The maximum value of the output signal of the photodetector 8A at the time when is located near the reflection angle θ1 can be used, and as the specular reflection intensity ■3□ for the light beam at the incident angle θ2, the photodetector 8B has the reflection angle θ2. The maximum output signal of the photodetector 8B at the time when it is located nearby ÷ Ik4田1^L>1−−At+PikL−*
As the J-j>Ifeb heat-mrΣ2, a value obtained by integrating (or adding) the output signals of the photodetectors 8A and 8B obtained at reflection angles of 0□ and 02, respectively, can be used.

An example of the signal processing system of the measuring device of the present invention when using the photodetectors 6A, 6B: 8A, 8B as described above is shown in the sixth section.
As shown in the figure.

In FIG. 6, each photodetector 6A, 6B: 8A.

The output signals of 8B are sent to amplifiers 9A, 9B,
:10A, is amplified by IOH, and becomes an electrical signal that can be inputted from a weak electrical signal to the next stage signal processing device 11 with sufficient sensitivity. Their amplifier 9A.

9B: The output signals of lOA and IOH are sent to the signal processing device 11
, and has a fixed proportional relationship with the specular reflection intensity l11m ''82, the total reflection amount Σ8.Σ2, and the incident light intensity I01.I.2, that is, the specular reflection intensity signal signal,
t I82', total reflection amount signals Σ1', Σ2', and incident light intensity signals I0,', IO2'. That is, in the case of the above-mentioned detector configuration, the photodetectors 8A and 8B receive the specular reflection intensity signal "81'#"@2' which is proportional to the specular reflection intensity Is□, 1.2, respectively, at the reflection angle θ, 0. Determine the maximum value of the signal at the time when the signal is located nearby, and also calculate the total reflection amount Σ1. Σ
As the total reflection amount signals Σ1' and Σ2' proportional to 2, the amount obtained by integrating (or adding) the signals obtained over the reflection angles θ0 and 0□ of the photodetectors 8A and 8B can be calculated. The signals outputted from the signal processing device 11 in this way, □′,
■, □', ΣI', Σ2', 'o1'p''. Each signal of □' is input to the divider 12, and η1 and η2 defined by the following equations (9) and 61 are calculated. Ruo like this II
, 'p I82' are divided by Σ, ', Σ2', respectively. The value of η2 corresponds to a value obtained by removing error factors caused by fluctuations in light source intensity and fluctuations in total reflectance of the surface to be measured with respect to the specular reflection intensity corresponding to the incident angle θ1° θ2. Therefore η1. η2 is expressed as (4) and (6), respectively.
By using Ir as (specular reflection intensity) in the equation, it is possible to correct or reduce roughness measurement errors due to variations in light source intensity and variations in total reflectance of the surface to be measured. Therefore, in the device of the present invention, η8. η2 is input to the calculation output device 13, and is stored in advance in this calculation output device 13 (4)
The values of σ and σ are determined from the relationship in equation (6), and the values are output. That is, η corresponding to the incident angle θ is used as I in equation (4), and η2 corresponding to the incident angle θ2 is used as I in equation (6), and σ,
The values of σ7 are output. Here, although the relationship between equations (4) and (6) can be determined by theoretical calculation, it is actually easier to use a calibration curve determined experimentally. That is, a calibration curve that determines the relationship between η1 and σ and a calibration curve that determines the relationship between η2 and σA are created in advance through experiments, and based on these calibration curves, η1. η2 to σ,
σA can be calculated.

As described above, the variance σ of the height distribution of the surface profile as amplitude information and the slope information σ2, which is the ratio of that σ to the autocorrelation distance T, can be obtained as a roughness parameter. Of course, depending on the situation, the arithmetic output device 13 may be provided with a function of calculating T from σ and σ force, and output σ and T (therefore, amplitude information and frequency information).

In the above example, the signal corresponding to the specular reflection intensity is
Reflection angle exactly 01. Instead of using the reflection intensity detection signal at the position θ2, the maximum reflection intensity I, 1', 1. around the reflection angle θ1° θ□ is used. , I is used, so
When a change in the geometrical arrangement such as vibration occurs in the object to be measured (
For example, correct values can be detected even when measuring the roughness of the surface of a moving object.

Furthermore, in the above example, η1. In order to calculate η2, use (9) above.
As shown in Equation 4, 18□'1ml is divided by signals Σ1' and Σ2' that are proportional to the amount of total reflection, but if the total reflectance can be considered to be approximately constant #1, (9) , Σ1' and Σ2' of Equation 61 are signals proportional to the incident light intensity. ,′
.

■. 2' and replace I81'+I84' with "0"
The value divided by 1' j I03' can also be used as η,, η2. In this case, roughness measurement errors due to variations in the total reflectance of the surface to be measured are not corrected, but errors due to variations in light source intensity are corrected or reduced.

Furthermore, in the examples of FIGS. 5 and 6, the photodetector 8A
, 8B may be performed by the stepping motor 14 and its driver 15 in accordance with a timing signal from the arithmetic output device 13, for example. It is also possible to use image sensors such as solid-state cameras as the photodetectors 8A and 8B, and in this case, the scanning function of the photodetectors is not necessary. Using some of the information obtained in this way, it is also possible to obtain information regarding deposits such as dirt and oil films on the surface to be measured. That is, this is a function related to the second invention of the present application, which will be explained next.

In general, the reflectance (total reflectance when reflected light is scattered) of an object surface has a relationship with the incident angle θ and the refractive index n of the surface as shown in FIG. 7, based on Fresnel's formula. That is, the angle of incidence θ and the refractive index n of the surface
Since the reflectance changes in a fixed relationship and the refractive index n of the surface is related to the type and thickness of the substance attached to the surface, different incident angles θ8 can be obtained as shown in the following αn,on formula.
．． Signals Σ, ′, Σ2′ proportional to the amount of total reflection at θ2
and a signal I proportional to the incident light intensity. , ', I02' ratio ζ0. By subtracting ζ2, information regarding the surface deposits (type of substance, film thickness, etc.) can be obtained.

ζ1=Σ, /, /1 o, / ...QkaJ
・=X, /x・・・' ・・・・・・0埠Here, to explain the deposit information in more detail, the easiest way to detect the presence or absence of deposits is to use the signal Σ1 corresponding to the amount of total reflection. There is a method for detecting fluctuations in Σ or Σ2', but this alone is extremely insufficient as information on the deposits, so in the case of the present invention, the type and amount of deposits (film thickness) are determined as follows. ) is estimated.

In other words, the reflectance when there is no deposit at the incident angle 0□, θ2 is rl, rQ, and the reflectance when there is deposit is R.
1, R2, the following relationship generally holds.

R,= ,e-to 1d"5eC01, ,song QIH2=
2d+secθ2 to C26-, -10. (14 Here, d is the film thickness of the deposit, K, , K2 are constants specific to the deposit. Also, ri, C2 are constants specific to the surface to be measured in the case where there is no deposit. The reflectances R1 and R2 in a certain case can be calculated from the C1n formula and H formula as C0,
With C2 as a constant, it is expressed as R, = α1ζ1 ...... 0 o'clock R2 = C2C2 ...... α. Therefore, al, formula (G) and (14,06
From the formula, ξ11-1o [α1ζ□/r1') = -1
clsecθ, ...αηξ2−10g (α2ζ2/
``2:) = 2d'' Secθ2...0.

Here ξ1. ξ2 is αη, ζ as shown in the a barrel formula.

Since it is a function of C2, in the end Qη, C1. The values of 1d and K2d can be derived from the value of C2. Furthermore, αη, ξ from formula C11
, /e2=K1/ can be expressed as 2... (to). For a substance with K, ) K2, 1°K2 is a value specific to the adhered substance as described above, so the type of the adhered substance can be estimated from K,/2. Also,
When the value of K1A2 is constant, the value of the deposit film thickness d can be estimated from the αφ equation.

Therefore, in the example shown in FIG. 6, in the divider 12
II) Calculate the values of C1 and C2 according to the on formula,
The C1 and C2 signals are input to the calculation output device 13, and the calculation output device 13 calculates the value of 1A2, for example, as described above, and outputs it as information regarding the deposit.

Next, an example of actually measuring surface roughness using the measuring device of the present invention will be described.

In this example, the specific configuration of the measurement device is as shown in FIGS. 5 and 6, that is, scanning type silicon photodiodes are used as the reflected light detectors 8A and 8B, and the measurement target is Roughness range σ is 0.2 to 0.5
A cold-rolled steel plate bright material having a diameter of approximately μm was used, and the measurement was carried out while the cold-rolled steel plate was traveling at a speed of approximately 100 m1n.

The light sources 2A and 2B are He-Ne laser light sources (wavelength λ
= 0.633 μm), and the incident angle is θ, = 750, θ
By setting 2=to0, the above formulas (7) and (8) were satisfied. Then, the output signals of the photodetectors 6A, 6B: 8A, 8B are amplified by the amplifiers 9A, 9B: IOA, IOB, and the output signals of the photodetectors 6A, 6B: IOA, IOB are amplified by the signal processing device 11 as described above.
s ``s3' l '01' + I02'#Σ1/
, Σ21, and the divider 12 calculates the η1
．． η2゜C0,C2 is calculated, and the calculation output device 13 calculates a calibration curve that determines the relationship between η1 and σ, and calculates η2 and σ/
Determine σ and σ2 using a calibration curve that determines the relationship with T, and also calculate the above-mentioned K1. Calculate n2 and calculate these σ.

C2vepK IA2 was output.

The calibration curve and output data for σ and σA in this example are shown in FIGS. 8 and 9.

As is clear from the above description, the surface texture measuring device of the first invention is capable of obtaining surface roughness information with high accuracy according to the roughness range of the surface to be measured and the wavelength of the incident light beam. Incident angle θ1. The range of θ2 is specifically set. Therefore, according to the apparatus of the first invention, surface roughness information, that is, amplitude information σ and inclination information σA (
In addition, the detection signal processing takes into consideration error factors such as fluctuations in light source intensity and total reflectance of the surface to be measured, so measurement accuracy due to these error factors may be reduced. The remarkable effect of suppressing the decrease as much as possible and being able to measure the surface roughness with higher accuracy can be obtained.

Further, according to the surface texture measuring device of the second invention, not only the surface roughness information as described above but also information regarding deposits such as dirt and oil film on the surface to be measured can be obtained at the same time. It is possible to achieve the effect that quality control of product sheets and the like can be more easily performed in the steel sheet manufacturing process and the like.

[Brief explanation of the drawing]

Figure 1 shows the specular reflection intensity IS and 4 for light projected onto a rough surface.
7 (father σ), Figure 2 is a diagram showing the relationship between specular reflection intensity Is for light projected onto a rough surface and 4 forces (father σ2), and Figure 3 is a diagram showing the relationship between g. A correlation diagram showing the relationship between Is and 1/'i\/4r (■σ, etc.) when the value is within the range of 100 to 3000. Figure 4 is a correlation diagram showing the relationship between Is and 1/'i\/4r (■σ, etc.) when the value of g is within the range of 10 to 100. ■8 and Jii7'r (oca/lI')
(F correlation diagram showing the D relationship, Fig. 5 is a schematic diagram showing the principle of an example of the optical system in the measuring device of the present invention, Fig. 6 is the present invention when the optical system shown in Fig. 5 is used) Fig. 7 is a diagram showing the relationship between surface reflectance, incident angle, and surface refractive index; Fig. 8 is a block diagram showing the signal processing system in a device for determining η, and σ, and FIG. 9 is a diagram showing data and a calibration curve regarding η2 and σ/T measured using the apparatus of the present invention. LA, IB... Laser beam (incident 2B... Laser light source (light projection means), 3... Measured Li1lr16A, 6B... Photodetector (second light detection means), 8A, 8B... Photodetector (first photodetection means), 11... signal processing device, 12... divider, 13
...Arithmetic output device. Figure 2 Figure 3 0 2.0 4.0 6.0 Figure 7 Angle of incidence θ Figure 8 Te (μm)

Claims (2)

[Claims] (1) A device that obtains amplitude information, tilt angle information, or frequency information of the surface profile of the surface to be measured from the intensity of reflected light obtained by projecting a beam of the same wavelength onto the surface to be measured at two different incident angles. In addition, the wavelength of the light beam is λ, the dispersion of the height distribution of the surface profile of the measured surface is σ, and the two incident angles are θ! . θ, the incident angle θ1. a light projection means for setting θ2; a first light detection means for detecting the specular reflection intensity and total reflection amount corresponding to the incident light beams at each incident angle of 0□ and θ2; a first light detection means for detecting a part of each incident light beam a second light detection means for extracting and detecting a light intensity proportional to the incident light intensity; and: an incident light intensity signal corresponding to each incident light flux, a specular reflection intensity signal, and A signal processing device that receives a total reflection amount signal; A divider that divides a specular reflection intensity signal by a corresponding incident light intensity signal or total reflection amount signal: Amplitude information and tilt angle information or frequency information from the output of the divider. and a calculation output device that calculates and outputs. (2) In a device that obtains amplitude information and tilt angle information or frequency information of a surface profile of a surface to be measured from the intensity of reflected light obtained by projecting a light beam of the same wavelength onto the surface to be measured at two different incident angles. , the wavelength of the light beam is λ, the dispersion of the height distribution of the surface profile of the surface to be measured is σ, and the above 2
A light projection means in which the incident angles 9□, θ2 are set to satisfy (4πσ/λ・cosθ,)≦4 10≦(4πσ/λ'cosθ2)≦100, where the two incident angles are θ1,02; Incident angle θ8. a first light detection means for detecting specular reflection intensity and total reflection amount corresponding to each incident light flux of θ2; and a second light detection means for extracting a part of each incident light flux and detecting a light intensity proportional to each incident light intensity. and a light detection means: an incident light intensity signal corresponding to each incident light beam based on the output of the respective party detection means;
A signal processing device that receives a specular reflection intensity signal and a total reflection amount signal: divides the specular reflection intensity signal by the corresponding incident light intensity signal or total reflection amount signal, and divides the total reflection amount signal by the corresponding incident light intensity signal. and a calculation output device that calculates and outputs amplitude information, tilt angle information, or frequency information and information regarding surface deposits from the output of the divider. measuring device.