JP2002122419A - Flatness measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a cost by applying a constitution in which only one range finder is used. SOLUTION: A laser beam emitted from a laser diode 4 is reflected by a rotating mirror 5. The reflected laser beam gives the state where the surface of a measuring object 1 is scanned from the upstream side to the downstream side, and the laser beam reflected by the surface of the measuring object 1 is received by a light-receiving lens 7. Only the laser beams reflected on the spots P1, P2 can pass a slit plate 8 and reach a photomultiplier 9. When inputting respectively distance detection pulses on each spot from the photomultiplier 9, a flatness operation circuit 3 determines the distance from the range finder 2 to the surface of the measuring object 1 based on the time from the point of time when a signal of a start pulse detector 6 is inputted, and furthermore operates the flatness.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flatness measuring device for measuring the flatness of the surface of a long object such as a rolled material.

[0002]

2. Description of the Related Art FIG. 6 is a perspective view showing the structure of a conventional flatness measuring device. Elongated DUT 1 such as rolled material
Moves at a predetermined speed on the production line in a moving direction indicated by an arrow. Such a long object to be measured 1 moves while the shape viewed from the side surface is in an approximately sinusoidal wavy state.

[0003] Above the DUT 1, two distance meters 101 and 102 for detecting a distance H between the DUT 1 and the surface of the DUT 1 are provided.
Are arranged at a distance R1 from each other, and the detection signals of these two distance meters 101 and 102 are output to a flatness calculation circuit 103. Flatness calculation circuit 103
Calculates the flatness of the surface of the DUT 1 based on the input of these detection signals. And these 2
A flatness measuring device is constituted by the two distance meters 101 and 102 and the flatness calculating circuit 103. Here, since the distances H at a plurality of points on the axis 1a of the surface of the DUT 1 are measured by the distance meters 101 and 102, the above R1 is referred to as a distance measurement section. Accordingly, a plurality of distance measurement sections are set along the moving direction on the surface of the DUT 1 moving in the direction of the arrow.

FIG. 7 shows a configuration of a distance meter 101 and a distance H.
It is explanatory drawing about the principle which measures. Note that the distance meter 102 is not shown because it has the same configuration as the distance meter 101. As shown in FIG.
Has a laser diode 104 as a light projecting means, a light projecting lens 105, a light receiving lens 106, and a line sensor 107 formed by a CCD.

[0005] The laser light emitted from the laser diode 104 passes through the light projecting lens 105 and is
The light is reflected at a point P1 on the surface at a reflection angle θ0, and the line sensor 107 receives the reflected light via a light receiving lens 106. The line sensor 107 at this time
Since there is a certain correspondence between the light receiving position and the distance H, the distance meter 101 can detect the distance H based on the light receiving position (light receiving pixel) on the line sensor 107.

FIG. 8 is a table showing an example of the correspondence between the position of the light receiving pixel (pixel) of the line sensor 107 and the detection distance. For example, if the line sensor 107 has a reflection angle θ
Assuming that the reflected light of 0 is received and the light-receiving pixel is the 100th light-receiving pixel, the range finder 101 can immediately detect that the detection distance is H from the chart of FIG. Further, when the position of the reflection point P1 is shifted upward or downward and the reflection angle becomes θ1 or θ2, respectively, the light receiving pixel position becomes the 90th or 110th position, respectively, and the detection distance from the chart of FIG. Becomes H−ΔH or H + ΔH, respectively.

Next, the content of the flatness calculation performed by the flatness calculation circuit 103 will be described. FIG. 9 is an explanatory diagram of the definition of the flatness of the surface of the DUT 1. When the wavelength of one cycle of the DUT 1 moving in the moving direction while waving in a sine wave shape is L, the arc length of the wave at this wavelength L is S, and the height of the wave is h, the flatness λ is It is defined by the following equation (1).

Λ = (h / L) × 100 [%] (1) However, the reason that equation (1) can be applied is that the object to be measured 1 is placed on a surface plate or the like and each dimension is measured in a stationary state. This is a case where measurement can be performed by a measuring instrument, and the formula (1) cannot be applied to a long object 1 such as a rolled material moving on a production line at a predetermined speed. . Therefore, the flatness is measured by a non-contact type flatness measuring device as shown in FIG. That is, as shown in FIG. 10, the arc lengths .DELTA.S1, .DELTA.S2, .DELTA.S3,... It is known from the fact that the moving speed of the object 1 is constant, and y can be obtained from the detection values of the rangefinders 101 and 102.) As shown in the equation (3), these ΔS1, ΔS2, ΔS3,. The arc length S is obtained as the sum of Then, as shown in the equation (4), the elongation ε is obtained by using the arc length S, and as shown in the equation (5), the flatness λ is obtained by the approximate expression using the elongation ε. be able to.

By the way, in the configuration shown in FIG. 6, two rangefinders 101 and 102 are used. The reason for using two rangefinders will be described. In FIG.
The state of the DUT 1 shown by the dashed line is at time t0, and the state of the DUT 1 shown by the solid line is time t1.
It is in. Here, consider the case where the point P1 on the dashed line moves to the point P1 on the solid line. If this movement is a complete parallel movement without any vertical displacement, The arc length ΔS1 can be obtained from the difference (H1−H0) between the detection distance H1 of the point P1 detected by only the distance meter 102 and the detection distance H0 of the point P0. Therefore, only one rangefinder is required.

However, in practice, each part of the DUT 1 is greatly displaced in the vertical direction, and moves on the manufacturing line while waving. H1 + α at time t1 when
1 (α1 is the amount of displacement), and the detection distance of the point P0 by the distance meter 102 at a later point in time is H0 + α0 (α0 is the amount of displacement). Therefore, the difference between the two detection distances is (H1 -H
0) + (α1−α0), which includes a shift amount (α1−α0) that is not canceled. That is, the distance meter 10
Y1 obtained using only 2 is inaccurate.

However, in addition to the distance meter 102, the distance meter 101
When the distance H0 of the point P0 and the distance H1 of the point P1 are measured at the same time, even if a vertical shift occurs, the shift amounts α0 and α1 are equal. If the difference between the detection distances is obtained, those deviation amounts are cancelled. In the configuration of FIG. 6, two distance meters 101 and 102 are used for this reason.

[0012]

However, the rangefinders 101 and 102 are very expensive, and the use of two identically configured ones as described above requires a correspondingly large amount of flatness measuring device. This is a major factor that hinders cost reduction.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a flatness measuring device having a configuration using only one rangefinder and capable of greatly reducing costs. And

[0014]

As means for solving the above-mentioned problems, according to the present invention, a plurality of distance measurement sections are set along a moving direction on a manufacturing line at a predetermined speed. Light is projected for each measurement section on the surface of the long object to be measured, and the distance to the surface of the measurement object in each measurement section is determined based on the reception of the reflected light reflected on the surface of the measurement object. A distance meter to be detected, and a flatness calculation for obtaining an arc length at a predetermined wavelength of the object to be measured based on each detection value from the distance meter, and calculating a flatness of the surface of the object to be measured based on the obtained arc length. Circuit, the distance meter, the light emitting means for emitting light for each of the measurement sections, and reflects the light from the light emitting means while rotating at a predetermined speed, The reflected light is applied to each measurement section on the surface of the object to be measured. Rotating mirror means for sequentially feeding a plurality of different points in the order from the upstream point side to the downstream point side, and light receiving lens means for receiving each light from the rotating mirror means reflected at a plurality of points on the surface of the object to be measured. A predetermined number of slits permitting passage of each light from the light receiving lens means, and slit plate means for sending each light passing through these slits toward the flatness calculation circuit side. The flatness calculation circuit is provided, based on a time from a measurement start time of each measurement section to a time when each light is input from the slit plate means,
The distance to the surface of the object to be measured is calculated.

According to a second aspect of the present invention, in the first aspect of the present invention, a time point at which the most upstream point among a plurality of different points in each measurement section of the surface of the measured object enters the light from the rotating mirror means. A start pulse detector installed so that light from the rotating mirror means is incident at an earlier point in time, and the flatness calculation circuit includes a start pulse detector for detecting the light from the rotating mirror means. The calculation is performed by using the time of incidence as the measurement start time of each of the measurement sections.

According to a third aspect of the present invention, in the first or second aspect, the predetermined number of slits of the slit plate means is two or three.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the flatness calculating means is deficient in the number of pulses of the detection value in each of the measurement sections input from the distance meter. In the case where there is a calculated value, the calculation using the detection value from the range finder is not performed for that section.

According to a fifth aspect of the present invention, in the first aspect of the present invention, an fθ lens or a parabolic cylindrical mirror is disposed between the rotating mirror means and the surface of the object to be measured. Each of the light beams transmitted to the plurality of points by the rotating mirror means is parallel to each other.

[0019]

FIG. 1 is a configuration diagram of a first embodiment of the present invention. The flatness measuring device according to this embodiment includes a range finder 2 and a flatness calculation circuit 3, and the range finder 2 includes a laser diode 4, a rotating mirror 5, a start pulse detector 6, It has a light receiving lens 7, a slit plate 8, and a photomultiplier tube 9.

The laser diode 4 emits laser light at each time interval corresponding to the distance measurement section R1 shown in FIG. The rotating mirror 5 has a polygonal reflecting surface, and is configured to rotate counterclockwise at a predetermined speed by a driving mechanism (not shown). Then, the laser light emitted from the laser diode 4 is received by its reflection surface, and the reflected light is sent to the start pulse detector 6, and then sent to a plurality of different points on the surface of the DUT 1 including P1 and P2. It has become. In this case, since the rotating direction of the rotating mirror 5 is counterclockwise, the order in which the laser light reaches the surface of the DUT 1 is from the upstream point to the downstream point.

The laser light from the rotating mirror 5 reflected by the surface of the DUT 1 is received by the light receiving lens 7, passes through the slit hole of the slit plate 8, and reaches the photomultiplier tube 9. . The photomultiplier tube 9 photoelectrically converts the laser light and outputs a distance detection pulse to the flatness calculating circuit 3.

The start pulse detector 6 outputs a start pulse detection signal to the flatness calculation circuit 3 when the laser light from the laser diode 4 reflected by the rotating mirror 5 is incident. The start pulse detection signal is a signal for notifying a measurement start point in each measurement section on the surface of the DUT 1. Flatness calculation circuit 3
When a distance detection pulse is input from the photomultiplier tube 9, the distance H to the surface of the DUT 1 is calculated based on the time from the input of the start pulse detection signal to the input of the distance detection pulse. The flatness described above is calculated using the distance H.

FIGS. 2A and 2B are cross-sectional views showing the structure of the slit plate 8 in FIG. 1. FIG. 2A shows a two-hole type slit plate 8 having two holes 8a and 8b, and FIG. 3 hole type slit plate 8 having holes 8a, 8b, 8c
A is shown.

FIG. 3 is an explanatory diagram showing coordinate values of measurement data obtained by using the slit plate of FIG. FIG. 3A shows two points H1 (x1, y1) and H2 (x) obtained by the two-hole type slit plate 8 of FIG.
2, y2). The flatness calculating circuit 3 calculates the entire arc length S using a straight line distance connecting the two points as a minute arc length ΔS, and further calculates the flatness λ using the arc length S. FIG. 3B shows three points H1 (x1, y1), H2 (x2, y2), and H3 (x3, y3) obtained by the slit plate 8A of the three-hole type shown in FIG. 2B.
Is shown. The flatness calculation circuit 3 can determine the entire arc length S by setting the distance on the quadratic curve connecting these three points to the minute arc length ΔS. Therefore, the use of the three-hole type slit plate 8A shown in FIG. 2B can provide a more accurate flatness.

Next, the operation of the first embodiment configured as described above will be described with reference to the time chart of FIG. When the laser diode 4 outputs laser light while the device under test 1 is moving on the manufacturing line, the laser light is reflected by the rotating mirror 5 that is rotating, and is incident on the start pulse detector 6. As a result, the start pulse detector 6 outputs a start pulse detection signal, and FIG.
As shown in (a), the flatness calculation circuit 3 inputs this start pulse detection signal at time t0.

When the rotating mirror 5 continues to rotate, the laser beam reflected by the rotating mirror 5 scans the surface of the DUT 1 from the upstream side to the downstream side. Further, the laser beam reflected by the surface of the DUT 1
And passes through the slit plate 8 to reach the photomultiplier tube 9. Here, in FIG. 1, the slit plate 8 used is of the two-hole type shown in FIG. 2A, and only the laser light reflected at the points P1 and P2 reaches the photomultiplier tube 9. It is supposed to. Therefore, as shown in FIG. 4 (b), the flatness calculating circuit 3
, A pulse at point P1 is input, and at time t2, a pulse at point P2 is input. The flatness calculation circuit 3 calculates the coordinate value H1 at the point P1 according to the time from time t0 to time t1.
(X1, y1) can be calculated, and the coordinate value H2 (x2, y2) at the point P2 can be calculated based on the time from time t0 to time t2.

When a three-hole type slit plate 8A is used instead of the two-hole type slit plate 8, the point P
Only the laser light reflected at 1, P2, and P3 (point P3 is not shown in FIG. 1) reaches the photomultiplier tube 9. Accordingly, as shown in FIG. 4C, the flatness calculating circuit 3 inputs the pulse at the point P1 at time t1, inputs the pulse at the point P2 at time t2, and outputs the pulse at time t2.
At 3, a pulse at point P3 is input. The flatness calculating circuit 3 calculates the coordinate value H1 (x1, y1) at the point P1 based on the time from time t0 to time t1, and calculates the coordinate value H1 (x1, y1) at time t0 to time t2.
Value H2 (x2, y2) at point P2 depending on the time
And the coordinate value H3 (x3, y3) at the point P3 can be calculated based on the time from time t0 to time t3.

By the way, the flatness calculating circuit 3 should be input due to dust falling on the surface of the DUT 1 while the DUT 1 is moving on the production line, or vapor existing in the measurement space. Pulses may be lost. In the case of FIG. 4 (b), if one of the two pulses is lost, the minute arc length between the two points cannot be calculated in the first place, so that there is no erroneous measurement. However, in the case of FIG. 4 (c), Even if one of the three pulses is lost, the distance between points P1 to P3 is calculated using the remaining two pulses. In this case, if one missing pulse is the pulse at the point P2, the error is small, but the point P1 or P3
If any one of the pulses is used, the error becomes large.
Therefore, in the present embodiment, when a three-hole type slit plate 8A is used, if any one pulse is lost, the distance calculation using the input pulse from the photomultiplier tube 9 is performed in the measurement section. Do not do. Then, for this measurement section, the entire arc length S is calculated using an appropriate distance value by a complement method or the like.

As described above, according to the flatness measuring apparatus of FIG. 1, the configuration using only one rangefinder has substantially the same function as the conventional device using two or three rangefinders. Obtainable. Therefore, the cost can be significantly reduced while maintaining the same quality and accuracy as the conventional device. In the above embodiment, 2
The number of pulses acquired in one measurement section is set to two or three using a hole type or three hole type slit plate. However, in order to calculate flatness with higher accuracy, a slit plate of four or more hole type is used. Can be used theoretically (for example, if measurement data at four points is obtained, higher accuracy can be achieved by third-order approximation). However, if the number of measurement data is four or more, the amount of calculation of the flatness calculation circuit 3 becomes enormous, and the processing time becomes long. Therefore, in practice, a configuration using a slit plate up to a three-hole type is adopted. It can be said that this is an appropriate configuration.

FIG. 5 is a configuration diagram of a second embodiment of the present invention. The distance meter 2A according to the second embodiment includes a first
Unlike the rangefinder 2 in the embodiment, the fθ lens 10 is disposed below the rotating mirror 5. Therefore,
The laser beams of various angles reflected by the rotating mirror 5 pass through the fθ lens 10 and become parallel laser beams to reach the surface of the DUT 1.

In the configuration shown in FIG. 1, since the projection angles of the laser light from the rotating mirror 5 to the surface of the object 1 are different from each other, the amount of reflected light on the surface of the object 1 is also different. It is required that the dynamic range of the photomultiplier tube 9 be large to some extent. However, in the case of the configuration in FIG. 5, since the projection angles of all laser beams are the same, the difference in the amount of reflected light is very small, and the dynamic range is large as in the configuration in FIG. Need not be. In the configuration shown in FIG. 5, the fθ lens 10 is used as a means for equalizing the projection angle from the rotating mirror 5, but the same effect can be obtained by using a parabolic mirror instead of the fθ lens 10. Obtainable.

[0032]

As described above, according to the present invention, a configuration using only one rangefinder can be realized, and a flatness measuring apparatus capable of greatly reducing costs can be realized. it can.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a first embodiment of the present invention.

FIG. 2 is a sectional view showing the structure of a slit plate 8 in FIG.

FIG. 3 is an explanatory diagram showing coordinate values of measurement data obtained by using the slit plate of FIG. 2;

FIG. 4 is a time chart for explaining the operation of the first embodiment.

FIG. 5 is a configuration diagram of a second embodiment of the present invention.

FIG. 6 is a perspective view showing a configuration of a conventional flatness measuring device.

FIG. 7 shows a configuration of a distance meter 101 and a distance H in FIG.
Explanatory drawing about the principle of measuring.

8 is a table showing an example of a correspondence relationship between a light receiving pixel position of a line sensor 107 and a detection distance in FIG.

FIG. 9 is an explanatory diagram of the definition of the flatness of the surface of the DUT 1 in FIG. 6 or FIG.

FIG. 10 is an explanatory diagram of a calculation for obtaining an arc length S in FIG. 9;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 DUT 1a Axis 2 Distance meter 3 Flatness calculation circuit 4 Laser diode 5 Rotating mirror 6 Start pulse detector 7 Light receiving lens 8, 8A Slit plate 8a-8c hole 9 Photomultiplier tube 10 fθ lens 101, 102 Distance meter 103 Flatness calculation circuit 104 Laser diode 105 Light emitting lens 106 Light receiving lens 107 Line sensor

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 2F065 AA06 AA28 AA47 BB13 BB15 DD00 DD06 DD13 FF12 FF32 GG06 GG08 JJ01 JJ05 JJ17 LL10 LL15 LL28 LL62 MM16 QQ25 QQ26 QQ27 QQ32 5J084 AA05 BB01AD01

Claims (5)

[Claims] An apparatus moves on a manufacturing line at a predetermined speed and emits light for each measurement section to a surface of a long object to be measured in which a plurality of distance measurement sections are set along the movement direction. A distance meter that detects the distance to the surface of the object in each measurement section based on the reception of the light reflected on the surface of the object; and an arc length of the object at a predetermined wavelength from the distance meter. A flatness calculating circuit that calculates the flatness of the surface of the measured object based on the obtained arc length, and a flatness calculating circuit that includes: A light projecting means for projecting light from the light projecting means while rotating at a predetermined speed, and reflecting the reflected light upstream to a plurality of different points in each measurement section of the surface of the object to be measured. Send in order from point to downstream point Rotating mirror means for emitting light, light receiving lens means for receiving each light from the rotating mirror means reflected at a plurality of points on the surface of the object to be measured, and a predetermined number of slits permitting passage of each light from the light receiving lens means And a slit plate means for sending each light passing through the slit toward the flatness calculation circuit side, wherein the flatness calculation circuit is configured to start the measurement in each of the measurement sections. A flatness measuring device for calculating a distance to the surface of the workpiece based on a time until each light is input from the slit plate means. 2. The light from said rotating mirror means enters at a point earlier than the time at which the most upstream point among a plurality of different points in each measurement section on the surface of the object enters the light from said rotating mirror means. The flatness calculation circuit, the time when the start pulse detector receives light from the rotating mirror means as the measurement start time of each measurement section, The flatness measuring device according to claim 1, wherein the flatness measuring device performs an operation. 3. The flatness measuring device according to claim 1, wherein the predetermined number of slits of the slit plate means is two or three. 4. The flatness calculating means, when there is a defect in the number of pulses of a detection value in each of the measurement sections input from the range finder, uses the detection value from the range finder for that section. The flatness measuring device according to any one of claims 1 to 3, wherein the calculated operation is not performed. 5. An fθ lens or a parabolic cylindrical mirror is disposed between the rotating mirror means and the surface of the object to be measured, and each light sent to the plurality of points by the rotating mirror means is parallel to each other. The flatness measuring apparatus according to any one of claims 1 to 4, wherein: