JPH11257925A - Sensor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately measure the thickness or refractive index of a transparent work such as glass, without contacting and without depending on the inclination angle of the transparent work. SOLUTION: A projector radiates a conical converged light. When a left light beam b is incident on a transparent work 1 at an incident angle θ1 -θa , it refracts at a refraction angle θd . When coming to the back side of the transparent work 1, it again refracts into a light beam d with a deviation 1d occurring between the light beams b and d. About a right light beam a, a deviation 1c occurs. From these deviations an elliptic profile is obtd. at a light receiving position. By quantitatively analyzing the optical axis change and light receiving profile, the inclination angle θ1 and thickness T of the transparent work 1 can be measured if the transparent work's refractive index is known.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sensor device for measuring the thickness, inclination and refractive index of a transparent body by transmitting a focused light through a transparent body such as glass and quantitatively analyzing a light receiving profile thereof. Things.

[0002]

2. Description of the Related Art There are many contact-type devices for measuring the thickness of an object to be measured. For example, in a micrometer,
The object to be measured is scissors with an anvil and a spindle, and the thickness is measured with a micrometer head by rotating the spindle. The surface roughness meter traces the surface of the object to be measured with a diamond probe, and can measure the undulation of the surface, which is the thickness unevenness of the object to be measured, in μm units. Since such a mechanical measuring instrument or measuring device can directly know the measured value, in the field of machining,
It has been widely used since ancient times and is still being used today.

[0003]

In the measuring instruments as described above, the surface hardness of the measuring probe is often harder than the surface of the object to be measured in order to ensure durability and measuring accuracy. Therefore, when such a mechanical measuring device contacts or traces the surface of the object to be measured, unnecessary particles or oil may adhere to the surface of the object to be measured or may be damaged. In the case of metal processing, there is no problem, but when the object to be measured is a glass substrate on which a circuit portion is formed like a liquid crystal panel, or when the material is a transparent resin having a low hardness, it is easily scratched and a mechanical measuring device is used. I can not use it.

In order to measure the undulation of the entire surface of the measured object, to measure the thickness of the measured object, and to measure the thickness unevenness of the entire measured object, it is necessary to trace the entire surface of the measured object. In the case of the above-described mechanical measuring device, it takes a long time to measure, not to mention that the entire surface of the object to be measured is damaged.

Some non-contact type gap measuring devices use a change in capacitance or a change in magnetic impedance. However, there is a material limitation on an object to be measured. Also, prior calibration is required.

Further, as a non-contact type measuring device mainly using glass or the like as an object to be measured, a light beam is projected onto a glass substrate, and the thickness of the glass substrate is determined based on the reflected light from the front surface and the reflected light from the back surface. There is something to measure. Since the principle is to measure the optical path in the glass substrate, if the glass substrate is inclined with respect to the optical axis, the optical path becomes longer and an error occurs in the thickness measurement.

For example, the thickness measurement of a glass substrate is also performed in a manufacturing process of a liquid crystal panel or the like. However, in recent years, the shape of the glass substrate has become large and its thickness is thin, so that the glass substrate being measured is warped. For this reason, an angle error occurs between the measurement portion of the glass substrate and the optical axis of the measurement system, and as a result, there has been a problem that accurate thickness measurement cannot be performed over the entire object to be measured.

The present invention has been made in view of such a conventional problem, and transmits a focused light obliquely with respect to a transparent body such as glass, and changes the optical axis and the light receiving profile thereof. An object of the present invention is to realize a sensor device capable of measuring the thickness, inclination, and refractive index of a transparent body by performing quantitative analysis.

[0009]

According to a first aspect of the present invention, there is provided a sensor device for detecting a thickness of a transparent body as an object to be measured, wherein the light projecting unit projects a conical convergent light; A light receiving unit that is disposed at a focus position of the focused light when there is no transparent body and has a two-dimensional light receiving element that receives transmitted light that passes through the transparent body that is held at an angle to the central optical axis of the light projecting unit And a light receiving profile determining means for detecting a profile of the transmitted light obtained by the light receiving unit, and a refractive index of the transparent body and an elliptical profile obtained from the light receiving profile determining means, in a short axis direction and a long axis direction. An inclination angle calculating means for calculating an inclination angle of the transparent body in a measurement area by detecting an axial expansion ratio; an inclination angle of the transparent body obtained by the inclination angle calculating means; and a light receiving profile determining means From The minor axis direction and major axis direction of the expansion ratio of the profile that is, is characterized in that it comprises a and a thickness calculating means for calculating a thickness in the measurement region of the transparent body.

According to a second aspect of the present invention, there is provided a sensor device for detecting an inclination angle of a transparent body which is an object to be measured, wherein a light projecting unit for projecting a conical convergent light is provided. A light receiving unit having a two-dimensional light receiving element for receiving transmitted light passing through a transparent body held at an angle to the central optical axis of the light projecting unit, and A light receiving profile determining means for detecting a beam profile of the transmitted light obtained in the step, and an elliptical profile obtained from the refractive index of the transparent body and the light receiving profile determining means, the spread in the short axis direction and the long axis direction. And a tilt angle calculating means for calculating a tilt angle in the measurement region of the transparent body by detecting the ratio.

According to a third aspect of the present invention, there is provided a sensor device for detecting a refractive index of a transparent body which is an object to be measured, wherein the light emitting section projects a conical convergent light, and the transparent body is not provided. A light receiving unit having a two-dimensional light receiving element for receiving transmitted light passing through a transparent body held at an angle to the central optical axis of the light projecting unit, and A light receiving profile determining means for detecting the profile of the transmitted light obtained in the step, a tilt angle and a thickness of the transparent body inputted from the outside, and a short axis direction and a long axis obtained from the light receiving profile determining means. A refractive index calculating means for calculating a refractive index of the transparent body from a spread ratio of a profile in a direction.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION A sensor device according to an embodiment of the present invention will first be described based on its measurement principle. FIG.
FIG. 2 is an explanatory diagram showing a basic measurement principle of the sensor device of the present invention. In this figure, the refractive index of air is n ₁ (= 1)
The object to be measured is a parallel plate transparent body 1, the thickness of which is T, and the refractive index is n ₂ . The transparent body 1 may be a translucent body as long as it has a light transmitting component. The normal direction of the transparent body 1 is + N, -N, and the incident point P on the + N axis from the light projecting unit 2
_The light beam 3a is input toward ₁ . When the incident angle of the light beam 3a and theta ₁ with respect to + N axis, the light beam 3a is refracted inside the transparent body 1 so as to satisfy the expression (1) relationship. Therefore, there is a relationship of the formula (2) between the incident angle θ ₁ , the refractive index n ₂ of the transparent body 1 and the refractive angle θ ₂ .

(Equation 1)

[0013] Light beams 3b of the transparent body in 1 come to the exit surface, refracted at the exit point P _2. The exit angle of the light beam 3c with respect -N shaft is again output theta ₁ becomes the space of the refractive index n _1. At this time, assuming that the shift amount of the light beam 3c with respect to the axis of the light beam 3a is D, the relationship of Expression (3) is established. When the thickness T is expressed by using the equation (3), (4)
Expression.

(Equation 2)

Therefore, in the light receiving surface perpendicular to the optical axis of the incident light,
When the light receiving unit 4 having the two-dimensional photoelectric conversion element is provided, the shift amount D can be measured. By comparing the center of gravity of the light receiving spot with and without the transparent body 1 as described above, the thickness T of the transparent body 1 can be measured using Expression (4). In addition, as the light receiving section 4, C
A CD or a PSD (Position Sensitive Device) is used.

In order to accurately measure the thickness T of the transparent body 1,
It is necessary to know the inclination angle θ ₁ of the transparent body 1 having the same relationship as the incident angle θ ₁ . In particular, when the transparent body 1 is a large glass substrate, when the measurement is performed while holding the periphery thereof, the glass substrate itself bends, so that the incident angle θ ₁ varies within a predetermined range depending on the measurement location. Therefore, in the sensor device of the present embodiment, the astigmatism method is used for measuring the incident angle.

[0016] FIG. 2 (a) (x, y , z) in space, from the origin _{(0,0,0) (0, y 0} , 0) reference surface conical converging light to focus at It is assumed that the light is irradiated toward (x, y ₀ , z). This surface is used as a reference surface on which a photoelectric conversion element such as a CCD is provided. The transparent body 1 of a parallel plate having a thickness T and a refractive index n ₂ with respect to this reference plane is inclined along the z-axis from the reference plane, and the inclination angle θ
Assume that it is held at ₁ . In this case, the normal line N of the transparent body 1 is inclined by θ _{1 with} respect to the incident optical axis (y-axis direction). In this case, the optical path of the circular converged light is different depending on the inclination direction. Therefore, when a conical focused light is received, its light receiving profile becomes elliptical. FIG. 2B is a plan view of a light receiving profile of the reference surface, and a rectangular area surrounded by a solid line is a light receiving area of the light receiving unit 4.

The converging point when there is no transparent body 1 is P _F , whereas the central point of the light receiving profile when there is the transparent body 1 is P _f ′. In this light receiving profile,
A major axis length of the light-receiving spot (profile) and D _P,
Assuming that the short axis length of the light receiving spot is D _R , D _P > D _R as shown in the figure.

Next, such conical focused light is converted into a light beam as shown in FIG.
When the light is incident on the transparent body 1 as shown in FIG. 3A, the relationship between the incident light of the transparent body 1 and the emitted light of the transparent body 1 will be quantitatively described using FIG.

FIG. 3 shows the case where the transparent body 1 is held obliquely with respect to the y-axis direction which is the central optical axis of the light projecting portion.
y) It is sectional drawing along a plane, and has shown the optical path when a conical focused light is incident. For example, parallel light is input from a light source (not shown) to a convex lens provided in the (xz) plane. At this time, the parallel light is converted into a focused light by the focusing action of the convex lens. In this case, if the center position of the convex lens is x = 0, z = 0, its effective diameter is D _L , and the distance to the light receiving unit is La, y ₀ = −La, and La becomes equal to the focal length of the convex lens. Note that the output light from the light source may not be parallel light, but in that case, the distance La does not become the focal length of the convex lens, but simply becomes the focusing distance of the focused light when there is no transparent body 1.

If the transparent body 1 is not provided, the conical convergent light is not refracted but passes through the optical path shown by the dotted line and converges at the position P _F (0, -La, 0) on the light receiving surface.

Next, consider the case where the transparent body 1 is provided at an angle of θ _{1 with} respect to the (x, y ₀ , z) plane.
When the light on the optical path b having an angle of θ _{a with} respect to the y-axis is incident on the point P ₃ of the transparent body 1, the incident angle with respect to the normal line of the transparent body 1 is (θ ₁ + θ _a ). When the light enters the transparent body 1, as shown by the solid line in the figure, reaches a point P ₄ of the rear surface of the transparent body 1 is refracted at refraction angle theta _d. Thereafter, the light is refracted again, and the light is output downward along an optical path d parallel to the optical path b. The distance along the x-axis between the optical path d and the extension of the optical path b is l _d .

Similarly, consider the light on the optical path a which is symmetric with respect to the optical path b with respect to the y axis. This light, when it is incident at point P ₅ of the transparent body 1, the incident angle of the transparent body 1 with respect to the normal line becomes (θ ₁ -θ _a). When the light enters the transparent body 1, as shown by the solid line in FIG. 3 and FIG. 4, it reaches a point P ₆ on the back surface of the refractive transparent body 1 in refraction angle theta _c. Thereafter, the light is refracted again and light is output along an optical path c parallel to the optical path a. The distance along the x-axis between the optical path c and the extension of the optical path a is l _c . Where the angle θ
_1, θ _a, θ _c, and theta _d, a diameter D _L, the distance La, between the refractive index _{n 2, (5), (} 6), (7) the relationship equation is established.

(Equation 3)

In the (xy) plane shown in FIG. 3, the linear equations of the optical path a and the optical path b are as shown in equations (8) and (9), respectively.

(Equation 4)

In the (xy) plane, the linear equations of the optical path c and the optical path d are as shown in equations (10) and (11), respectively.

(Equation 5)

_Let P _f be the intersection of optical path c and optical path d,
When the deviation of the coordinates of the point P _f for _F and ([Delta] x, [Delta] y _P), the coordinate values of the point _{P f (x f, y f} ) are (10)
It is obtained by the equation (11). From these solutions, Δx = x
_f− 0, and Δy _P = | y _f | −La. Therefore, Δx and Δy _P are as shown in equations (12) and (13), respectively.

(Equation 6)

Next, a method of calculating the distances l _c and l _d will be described with reference to FIG. The point P ₅ on the upper surface in FIG. 3 similarly to the transparent member 1, the optical light path a is incident. When the angle of incident light with respect to the y axis and theta _a, the incident angle of the transparent body 1 with respect to the normal line becomes (θ ₁ -θ _a). The incident light is incident on the transparent member 1 in refraction angle theta _c. This refracted light is transparent 1
A point impinging of the back surface and P _6. When light to the outside of the transparent body 1 from this point P ₆ is output, the optical path c is parallel to the extension of the optical path a, it becomes displaced by a distance l _c a + x-axis direction.

The shift amount l of the output optical path c with respect to the incident optical path a
_{If c} is expressed using a trigonometric function, it becomes as shown in equation (14).

(Equation 7)

[0028] For a point P ₃ of the transparent body 1 of FIG. 3, the optical path b
A similar relationship holds for the light incident through.
In this case, θ _c = θ _d, so may be set as θ _a = -θ _a, the following (15) is established.

(Equation 8)

By substituting l _c obtained by the equation (14) and l _d obtained by the equation (15) into the equations (12) and (13), (x, y) due to the existence of the transparent body 1 is obtained. The displacement amounts Δx and Δy _P of the light receiving point on the plane can be calculated.

Next, the displacement Δy _R of the focal point on the (y, z) plane will be analyzed with reference to FIG. FIG. 5 is a partial cross-sectional view of the transparent body 1 cut along the (yz) plane. The plate thickness T of the transparent body 1 is T ′ when viewed from the (yz) plane, and T ′ is larger than T. In addition, transparent body 1
If the incident angle with respect to a perpendicular line parallel to the y-axis is θ _e and the refraction angle is θ _f , Expression (16) is established in the same manner as Expression (5). When the thickness T ′ is represented by using T, the expression (17) is obtained.

(Equation 9)

In FIG. 5, the optical paths of the light incident on the transparent body 1 are denoted by e and f, respectively, and the optical paths of the transmitted light of the transparent body 1 are denoted by g and h, respectively.
And The light rays on the optical paths e and f without the transparent body 1
Cross at _F When the transparent member 1 is positioned as shown in FIG. 5, the optical path g of the transmitted light, h intersect at a point P _f. Therefore, the vertical shift Δy _R is as shown in equation (18).

(Equation 10)

As described above, the shift amount Δy _P and the shift amount Δ
When y _R is obtained, it can be converted to the short axis length D _P of the light receiving spot using equation (19) and converted to the long axis length D _R of the light receiving spot using equation (20).

[Equation 11]

Assuming that the value of D _P / D _R is the spot ratio R,
A spot ratio R corresponding to the inclination angle θ ₁ of the transparent body 1 is obtained. For example, the refractive index n ₂ of the transparent body 1 is 1.5 and the thickness T is 1
mm, the lens diameter D _L is 10 mm, and the distance La
Assuming 0 mm, the spot ratio R with respect to the inclination angle θ ₁ has characteristics as shown in FIG. Here, the spot ratio R changes according to the inclination angle θ ₁ of the transparent body 1.

The formula for the spot ratio R is as follows:
Since the thickness T component is not included, the diameter D _P of the light-receiving spot, from D _R, without depending on the transparent body 1 thickness T, it is possible to detect the inclination angle theta ₁ of the transparent body 1.

Further, spot diameters D _P and D _{R on the} light receiving surface and
If the inclination angle θ ₁ is input with a predetermined accuracy and the refractive index n ₂ of the transparent body 1 is known, the thickness T of the transparent body 1 can be measured on the contrary.

A sensor device based on the above measurement principle will be described with reference to FIG. Figure 7 is a block diagram showing an overall configuration of a sensor device 10, when the refractive index n ₂ of the transparent body 1 are known, the inclination angle theta ₁ and the thickness T of the transparent body 1
2 shows a configuration for measuring. The light receiving unit 12 is attached at a position facing the light emitting unit 11. The light receiving unit 12
This is to detect the profile of the focused light that is incident when there is an object to be measured and when there is no object to be measured.
A light receiving element such as D is used, and is mounted on the (x, y ₀ , z) plane in FIG. The light projecting unit 11 outputs focused light obliquely to the object to be measured, and a laser diode or an LED is used as a light source.

The light emitting circuit 15 is a circuit for driving the light emitting element, and its light emission cycle is controlled by the oscillation circuit 14.
The driver 16 is a circuit for driving a CCD used for the light receiving section 12, and its clock is given by the oscillation circuit 14. The light receiving circuit 17 outputs the output signal of the light receiving section 12
This is a circuit for converting into a signal used in the arithmetic processing unit 18. When the light receiving element is a CCD, the light receiving circuit 17 holds the light receiving signal for each clock and sets the hold value to A.
/ D conversion.

The input unit 18 is for inputting the optical properties of the transparent object to be measured, for example, the refractive index n _2, and the tilt angle θ ₁ and the thickness T of the object to be measured by using a keyboard or the like. These data are stored in the storage unit 19.

The arithmetic processing unit 20 has a hardware configuration of C
It is composed of a PU and a memory, and calculates the thickness T of the object to be measured and calculates the inclination angle θ ₁ using the detection data input from the light receiving circuit 17 and the known data held in the storage unit 19. It calculates and outputs the result. Specifically, the arithmetic processing unit 20 includes the maximum received light amount searching unit 2
1. Light receiving profile determination unit 22, center of gravity deviation calculation unit 23, short axis length calculation unit 24, long axis length calculation unit 2.
5, division means 26, angle calculation means 27, thickness calculation means 2
Eight.

The maximum received light amount searching means 21 is a means for detecting the maximum value of all pixel values, assuming that the received light amount of each pixel output from the light receiving section 12 is a pixel value. The light receiving profile determining means 22 is a means for determining a light receiving level of each pixel by using a value obtained by multiplying a predetermined ratio from the maximum light receiving amount as a threshold, and determining a light receiving profile by binarizing each pixel value. .

If the light receiving profile output from the light receiving profile determining means 22 is an ellipse as shown in FIG. 2B, the center-of-gravity shift amount calculating means 23 calculates an intersection P _f ′ between the long axis and the short axis. a means for outputting a difference value Δx of the converging point P _F when the transparent member 1 is not a (= P _F -P _f ') as the centroid shift amount. The major axis length calculating means 25 calculates the major axis length D _P of the ellipse determined by the light receiving profile determining means 22, and the minor axis length calculating means 25 calculates the minor axis of the ellipse determined by the light receiving profile determining means 22. a means for calculating the length D _R. The dividing means 26 converts the major axis length D _P into the minor axis length D _R
And outputs the result of the division as a spot ratio R.

The angle calculation means 27 calculates the division value R output from the division means 26 and the refractive index n stored in the storage unit 19.
_This is a means for calculating the inclination angle θ ₁ of the transparent body 1 based on ₂ . The thickness calculating unit 28 calculates the value Δx output from the center-of-gravity deviation amount calculating unit 23, the refractive index n ₂ held in the storage unit 19, and the inclination angle θ ₁ obtained from the angle calculating unit 38, This is a means for calculating the thickness T of the transparent body 1. The output unit 29 outputs the calculation result of the thickness calculation unit 28, and the output unit 30 outputs the calculation result of the angle calculation unit 27.

(Measurement Example 1) The operation of measuring the thickness T of the transparent body, which is the object to be measured, using the sensor device 10 thus configured will be described. First, the transparent body 1 is not set, and the converging light is output by the light projecting unit 11.
At this time, the output of the light receiving circuit 17 is monitored, and the light projecting unit 11 and the light receiving unit 1 are controlled so that the light receiving spot diameter of the light receiving unit 12 becomes minimum.
2 or the distance between the light projecting lens and the light projecting element is adjusted. At this time, the maximum light receiving amount search means 21 searches which pixel of the light receiving element under the light projection has the maximum light receiving amount, and finds the coordinates of the pixel having the maximum light receiving amount of the light receiving element on the (x, z) plane. Reset the value to (0,0). This point is the convergence point P _F in FIG.

Next, the transparent body 1 is set between the light projecting section 11 and the light receiving section 12. In this case, the inclination angle θ ₁ of the transparent body ₁ is unknown. Further, the refractive index n of the transparent body is input through the input unit 18.
Enter ₂ . Next, focused light is output by the light projecting unit 11.

The maximum light receiving amount search means 21 checks the pixel value of each pixel of the light receiving element and detects the maximum pixel value. The light receiving profile determination unit 22 binarizes each pixel value using a threshold value for the obtained maximum pixel value, and determines a light receiving profile. Since the light receiving profile is an ellipse as shown in FIG. 2B, the center-of-gravity deviation amount calculating means 23 calculates the intersection coordinates of the major axis and the minor axis, and the coordinates (Δx, Δ
z) is determined as the amount of displacement of the center of gravity. In FIG. 2B, Δz = 0.

The major axis length calculation unit 25 detects a major axis D _P from the light-receiving profile. This value can be converted to Δy _P using equation (19). Also, the short axis length calculating means 24
Detects the short axis length D _R from the light receiving profile. This value can be converted to Δy _R using equation (20).

The dividing means 26 calculates the D
Using the _P and D _R, calculates the values of D _P / D _R as a spot ratio R. As can be seen from equations (19) and (20), the value of D _P / D _R is equal to the value of Δy _P / Δy _R. Therefore, when the value of Δy _P / Δy _R is calculated using the expressions (13) to (15), the expressions (17) and (18), the term of the thickness T of the transparent body 1 is deleted from this value. Angle calculation means 2
7 calculates the tilt angle θ ₁ by using the calculated spot ratio R and referring to a table stored in the storage unit 19 and representing the relationship between the tilt angle θ ₁ and the spot ratio R. This table shows the characteristics shown in FIG. 6, and the spot ratio R in this table indicates the thickness T of the transparent body 1 as described above.
There whatever value corresponds uniquely by the inclination angle theta _1. Therefore, even if the thickness T of the transparent body 1 is unknown, the output unit 30 outputs the inclination angle θ ₁ .

[0048] Then the thickness calculating section 28, a D _P value and D _R value obtained by the light receiving profile determining section 22, by the n ₂ value held in the storage unit 19, the output data of the angle calculating means 27 And the thickness T using formulas (17) and (18).
Is calculated. This value is output from the output unit 29 as a thickness measurement value of the transparent body 1.

(Measurement Example 2) Next, the operation of measuring the value of the inclination angle θ ₁ of the transparent body 1 will be described. As in the case of the measurement example 1, the light receiving profile is determined, and FIG.
It is assumed that an ellipse as shown in FIG. Major axis calculation means 25 calculates a major axis D _P from the light-receiving profile. The short axis length calculation unit 24 calculates the short axis length D _R from the light receiving profile.

The dividing means 26 calculates the D
Using the _P and D _R, calculates the values of D _P / D _R as a spot ratio R. The angle calculating means 28 uses the calculated spot ratio R to calculate the inclination angles θ ₁ and R held in the storage unit 19.
The inclination angle θ ₁ is calculated with reference to a table representing the relationship with Thus, the output unit 30 outputs the inclination angle θ ₁ .

(Measurement Example 3) Next, the operation of measuring the refractive index n ₂ of the transparent body 1 when the inclination angle θ ₁ and the thickness T of the transparent body 1 are known will be described. In this case, first, the inclination angle θ ₁ and the thickness T of the transparent body 1 are temporarily stored in the storage unit 19 via the input unit 18. Then detect the value of D _P and D _R in the same manner as in Measurement Example 1. If these values are known, the refractive index n ₂ of the transparent body 1 can be calculated using the equations (17) and (18).

Next, an example of the sensor head of the sensor device will be described with reference to FIG. FIGS. 8A and 8B are cross-sectional views showing the configuration of the sensor head 13 of the sensor device 10, in which FIG. 8A is a cross-sectional view, and FIG. This sensor head 1
3 is a U-shaped frame as shown in FIG.
The light emitting unit 11 and the light receiving unit 12 are attached.
The light projecting unit 11 includes a light projecting element 11a as shown in FIG.
And a light projecting lens 11b. The light projecting lens 11b functions to converge the laser beam output from the light projecting element 11a, which is a point light source, into a conical shape. The light receiving section 12 has a CC
A two-dimensional photoelectric conversion element such as D is provided on the optical axis of the light projecting unit 11.

In such a structure, since the light projecting unit 11 and the light receiving unit 12 are arranged in the same frame, even if the sensor head 13 is moved, troublesome resetting work is not required. Measurement resolution of the object to be measured is higher the larger the value of the inclination angle theta _1. In the case shown in FIG.
°. The measurement of the thickness T, the measurement of the refractive index n _2, the larger the inclination angle of the object to be measured, the resolution is improved.

It should be noted that the thickness, the inclination angle, and the refractive index can be measured even for a translucent object that does not involve diffusion as an object to be measured.

[0055]

According to the first aspect of the invention, the thickness of the transparent body can be measured in a non-contact manner regardless of the transmittance. The transparent body is not damaged by the measurement. In particular, the transparent body being measured is bent when the area is large and the thickness is small.
In this case, even if there is a deflection, that is, a local change in the inclination angle,
The thickness of the measurement area can be accurately measured.

According to the second aspect of the present invention, the inclination angle of the transparent body can be measured without contact. The transparent body is not damaged by the measurement. By scanning the transparent body, the bending of the transparent body can also be detected.

According to the third aspect of the invention, the refractive index can be measured if the thickness and the inclination angle of the transparent body are known.

Further, according to the invention of any one of claims, it is not necessary to limit the mounting angle of the object to be measured when the object to be measured is mounted on the sensor device. In addition, the clearance between the light emitting unit and the light receiving unit can be secured, and the usability is good.

[Brief description of the drawings]

FIG. 1 is an optical path diagram showing a measurement principle when measuring a thickness of a transparent body in a sensor device of the present invention.

FIG. 2 is an explanatory diagram showing a profile of a light receiving spot generated by the inclination of a transparent body in the sensor device according to the embodiment of the present invention.

FIG. 3 is an explanatory diagram (part 1) illustrating an optical path of focused light passing through a transparent body in the sensor device of the present embodiment.

FIG. 4 is an explanatory diagram (part 2) illustrating an optical path of focused light passing through a transparent body in the sensor device of the present embodiment.

FIG. 5 is an explanatory diagram (part 3) illustrating an optical path of focused light passing through a transparent body in the sensor device of the present embodiment.

FIG. 6 is a characteristic diagram showing a relationship between a tilt angle θ ₁ of a transparent body and a spot ratio R in the sensor device of the present embodiment.

FIG. 7 is a block diagram illustrating an overall configuration of a sensor device according to the present embodiment.

FIG. 8 is a configuration diagram of a sensor head used in the sensor device according to the present embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Transparent body (measured object) 2, 11 Light projecting part 3a, 3b, 3c Light beam 4, 12 Light receiving part 10 Sensor device 11a Light projecting element 11b Light projecting lens 13 Sensor head 14 Oscillation circuit 15 Light projecting circuit 16 Driver 17 Light receiving circuit 18 Input unit 19 Storage unit 20 Arithmetic processing unit 21 Maximum light receiving amount searching means 22 Light receiving profile determining means 23 Center of gravity deviation calculating means 24 Long axis length calculating means 25 Short axis length calculating means 26 Dividing means 27 Angle calculating means 28 Thickness calculating means 29, 30 Output unit

Claims (3)

[Claims] 1. A sensor device for detecting the thickness of a transparent body which is an object to be measured, comprising: a light projecting unit for projecting a conical convergent light; and a converging position of the convergent light when there is no transparent body. And
A light receiving unit having a two-dimensional light receiving element for receiving transmitted light passing through a transparent body held at an angle to the center optical axis of the light projecting unit; and detecting a profile of the transmitted light obtained by the light receiving unit. The light receiving profile determining means, and from the refractive index of the transparent body and the elliptical profile obtained from the light receiving profile determining means, by detecting the spread ratio in the short axis direction and the long axis direction, the transparent body A tilt angle calculating means for calculating a tilt angle in the measurement area; a tilt angle of the transparent body obtained by the tilt angle calculating means; and a spread in a short axis direction and a long axis direction of a profile obtained by the light receiving profile determining means. A thickness calculating means for calculating a thickness of the transparent body in a measurement area from the ratio. 2. A sensor device for detecting an inclination angle of a transparent body as an object to be measured, comprising: a light projecting unit for projecting a conical convergent light; and a converging position of the convergent light when there is no transparent body. Placed,
A light receiving unit having a two-dimensional light receiving element that receives transmitted light that passes through a transparent body that is held at an angle to the center optical axis of the light projecting unit; and a beam profile of the transmitted light obtained by the light receiving unit. The light receiving profile determining means to be detected, and the refractive index of the transparent body and the elliptical profile obtained from the light receiving profile determining means, by detecting the expansion ratio in the short axis direction and the long axis direction, the transparent body And a tilt angle calculating means for calculating a tilt angle in the measurement area. 3. A sensor device for detecting a refractive index of a transparent body which is an object to be measured, comprising: a light projecting unit for projecting a conical convergent light; and a converging position of the convergent light without the transparent body. Placed,
A light receiving unit having a two-dimensional light receiving element for receiving transmitted light passing through a transparent body held at an angle to the center optical axis of the light projecting unit; and detecting a profile of the transmitted light obtained by the light receiving unit. The light receiving profile determining means, and the inclination angle of the transparent body and the thickness of the transparent body inputted from the outside, and the spread ratio of the profile in the short axis direction and the long axis direction obtained from the light receiving profile determining means, A refractive index calculating means for calculating a refractive index of the body.