JPH08271232A - Method and device for detecting form abnormality of columnar object - Google Patents

Abstract

PURPOSE: To provide a method and device for accurately detecting form abnormality of a columnar object by eliminating random noise. CONSTITUTION: By, while compensating time difference of passing of one part of a columnar object 1 between respective irradiation positions of inspection lights 54 and 56, integrating time waveform measured in each inspection light, the pulse corresponding to the form abnormality 2 of the columnar object 1 is integrated. The pulse corresponding to the form abnormality 2 has large pulse amplitude, so that difference is caused from pulse amplitude of noise pulse. By comparing magnitude of the pulse amplitudes, the pulse corresponding to the form abnormality 2 is easily distinguished from the noise pulse, so that form abnormality detection is possible with high precision by the elimination of random noise.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for detecting an abnormal surface shape of a columnar body such as an optical fiber.

[0002]

2. Description of the Related Art Conventionally, a method of measuring the outer diameter of a columnar body by irradiating the columnar body with light from the side and measuring the light and darkness of the light generated by the shielding of the columnar body with an image sensor or the like has been conventionally known. Are known. This method is described in, for example, Japanese Patent Laid-Open No.
7-127803.

Further, as a method for detecting an abnormality in the surface shape of the columnar body, a method as shown in FIG. 9 (a) is conventionally known. This is a method of irradiating a parallel light flux while moving the columnar body along the longitudinal direction, and detecting a component of the light flux not blocked by the columnar body with a photodetector. The parallel light flux is formed using a collimator lens or the like. As long as the columnar body has a constant outer diameter along the longitudinal direction, the level of the detected light intensity is also constant, but if the surface of the columnar body has a shape abnormality such as a concave portion or a convex portion, the light blocking rate is Since it changes, the detected light intensity also changes.
For example, when the convex portion formed on the surface of the columnar body crosses the parallel light flux as shown in FIG. 9A, a pulse-like level decrease as indicated by reference numeral 80 in FIG. 9B is detected. From the time when this change occurred and the moving speed of the columnar body,
It is possible to find at which position of the columnar body the shape abnormality has occurred.

However, with this method, it is difficult to accurately detect the change in the light intensity due to factors such as the vibration of the columnar body and the power fluctuation of the light source, and the change in the light intensity due to the abnormal shape. For example, as shown in FIG.
When a noise pulse as indicated by reference numeral 90 is detected due to vibration of the columnar body or the like, the pulse 80 and the pulse 90 are the same as long as the shape abnormality is detected based on the fact that the light intensity becomes equal to or lower than a predetermined threshold value. However, it is processed as a pulse due to the shape abnormality.

In order to solve this problem, a double beam method using two beams as shown in FIG. 10 (a) has been devised. This is based on the difference between the time waveform of the light intensity of the component of the first beam that was not blocked by the columnar body and the time waveform of the light intensity of the component of the second beam that was not blocked by the columnar body. Is a method of detecting.
As shown in FIG. 10B, the noises 90 and 91 due to the vibration of the columnar body are detected by the first and second beams at the same time. Therefore, the noises 90 and 91 are detected by calculating the difference between the two time waveforms. It is possible to detect only the pulses 80 and 81 that are canceled and are caused by the convex portions 2 of the columnar body 1.

[0006]

However, in the above-mentioned double beam method, when random noise which is detected by one beam but not the other beam occurs, the noise cannot be removed. For example, FIG.
Since the noise 92 as shown in 1 is detected only by the first beam, it remains as it is even if the difference between the time waveforms is obtained, and the pulses 80 and 81 based on the abnormal shape of the columnar body are detected.
Similar to the above, the shape is determined to be abnormal.

Airborne dust in the atmosphere is known as a cause of such random noise. When one suspended dust crosses one inspection beam, noise is generated, but unless another suspended dust crosses another inspection beam at the same time, noise is not detected by another inspection beam. Further, the vibration of the columnar body does not always show the same amplitude for each inspection beam depending on the vibration state, and therefore, it may not be completely removed by the double beam method.

The present invention has been made in order to solve the above problems, and an object of the present invention is to provide a method and an apparatus capable of highly accurately detecting a shape abnormality of a columnar body by eliminating random noise. And

[0009]

In order to solve the above-mentioned problems, the shape abnormality detecting method of the present invention is such that a plurality of inspection lights traveling in directions substantially parallel to each other are irradiated on a predetermined measurement line. The first step of moving the columnar body to be measured relative to the inspection light on the measurement line while irradiating each position, and detecting the component of the inspection light not blocked by the columnar body, The second step of measuring the time waveform of the light intensity of the component for each inspection light and the time waveform measured for each inspection light while correcting the time when one point of the columnar body passes each irradiation position are corrected. Accumulate,
And a third step of detecting a shape abnormality of the columnar body based on the obtained integrated time waveform.

The first step is preferably a step of irradiating a plurality of inspection lights formed by branching light from a single light source and having substantially the same light intensity to the irradiation position.

The first step is preferably a step of irradiating the irradiation position with the inspection light of the substantially parallel light flux.

Next, the shape abnormality detecting apparatus of the present invention inspects a measurement line by irradiating a plurality of inspection light beams traveling in directions substantially parallel to each other to a plurality of irradiation positions on a predetermined measurement line. A device for detecting an abnormality in the surface shape of a columnar body that moves relative to light, and (a) a light projecting unit that irradiates each irradiation position with each inspection light,
(B) a light receiving unit facing the light projecting unit with the measurement line interposed therebetween, which detects each inspection light and outputs a plurality of electric signals corresponding to the time waveform of the light intensity of each inspection light, (C) A plurality of electric signals are integrated while performing correction so that the time when one position of the columnar body passes each irradiation position is matched,
Signal processing means for outputting the obtained integrated electric signal,
(D) An abnormality determining means for detecting an abnormality in the shape of the columnar body based on the integrated electric signal.

The light projecting means splits a single light source and a plurality of inspection lights having substantially the same light intensity by branching the light emitted from the light source, and outputs each inspection light at a plurality of emission ends. And a light branching means for emitting light from each of the above.

Further, the light projecting means may further include a plurality of collimator lenses which are respectively arranged at positions where respective emitting ends of the light branching means are the focal points.

The above-mentioned optical branching means may include a plurality of optical fibers into which light from a single light source enters from one end thereof, and the other end of each of the optical fibers serves as the above-mentioned emitting end. In addition, an incident side optical fiber on which light from a single light source is incident, an optical branching unit that branches the light emitted from this incident side optical fiber to form inspection light, and each of these inspection lights A plurality of incident-side optical fibers to be incident may be provided, and the other end of each outgoing-side optical fiber may be the above-mentioned emitting end.

Further, the light receiving means is a plurality of light receiving portions respectively facing the respective emission ends of the light branching means, detects the inspection light emitted from the emission ends, and temporal waveform of the light intensity of each inspection light is detected. It may be provided with a device for respectively outputting an electric signal according to the above.

[0017]

When the surface shape of the columnar body is substantially the same along the longitudinal direction, the light amount of the component of the inspection light that is blocked by the columnar body becomes substantially constant, and the measured light intensity also becomes substantially constant. .
However, when a shape abnormality such as a convex portion or a concave portion occurs on the surface of the columnar body, the light amount of the inspection light shielded by the columnar body changes at the time when the abnormal portion passes the irradiation position of the inspection light. This change in the amount of light becomes a pulse generated at the passage time in the time waveform measured in the present invention.

In the shape abnormality detecting method of the present invention, the time waveforms measured for the respective inspection lights are integrated while correcting the time when one portion of the columnar body passes each irradiation position of the inspection light, The pulses corresponding to the abnormal shape of the columnar body are integrated. A noise pulse unrelated to the abnormal shape of the columnar body also appears in the time waveform of each inspection light, but a random noise pulse that is detected by one inspection light but not by another inspection light is not integrated. Therefore, among the pulses appearing in the integrated time waveform, the pulse corresponding to the abnormal shape has a large pulse amplitude, which causes a difference from the pulse amplitude of the noise pulse. Therefore, by comparing the magnitudes of the pulse amplitudes, it is possible to easily distinguish the pulse corresponding to the shape abnormality from the noise pulse, and it is possible to detect the shape abnormality with high accuracy without random noise.

When the intensity of the inspection light increases or decreases according to the change in the brightness of the light source, the amplitude of the pulse corresponding to the abnormal shape also increases or decreases, so that the above-mentioned effect of time waveform integration may not be sufficiently obtained. In the present invention, when the inspection light formed by branching the light from a single light source is used, the change in the intensity of the inspection light due to the change in the brightness of the light source is substantially the same among the inspection lights. The intensities are maintained substantially the same, and the situation where the intensities of the inspection lights are extremely different is prevented. As a result, the effect of integrating the time waveform can be surely obtained.

Further, when the inspection light of substantially parallel light flux is used, the light density of the inspection light tends to be constant at the irradiation position on the measurement line. Therefore, even if a minute vibration occurs in the columnar body in a direction intersecting with the inspection light, a large change in the amount of the inspection light shielded by the columnar body does not occur unless the inspection light is irradiated to the abnormal shape of the columnar body. Does not occur. As a result, noise is less likely to occur in the measured time waveform, so that suitable shape abnormality detection is performed.

Next, according to the shape abnormality detecting apparatus of the present invention, the plurality of inspection lights are irradiated to the columnar body, and the component of each inspection light which is not shielded by the columnar body is detected by the light receiving means. When a shape abnormality such as a convex portion or a concave portion occurs on the surface of the columnar body, the light amount of the inspection light shielded by the columnar body changes at the time when the abnormal portion passes the irradiation position of the inspection light. This change in the amount of light becomes a pulse generated at the passage time in the electric signal output by the light receiving means.

The signal processing means integrates the electric signals corresponding to the respective inspection lights while correcting the time at which one portion of the pillar passes each irradiation position of the inspection light, so that the shape of the column becomes abnormal. Corresponding pulses will be integrated.
A noise pulse unrelated to the shape abnormality of the columnar body also appears in each electric signal, but a random noise pulse that is detected by one inspection light but not by another inspection light is not integrated. For this reason, among the pulses appearing in the integrated electric signal, the pulse corresponding to the abnormal shape has a large pulse amplitude, which causes a difference from the pulse amplitude of the noise pulse.

The abnormality determining means distinguishes between the pulse corresponding to the shape abnormality and the noise pulse based on the difference in the pulse amplitude, and detects only the pulse corresponding to the shape abnormality. In this way, the shape abnormality detection device of the present invention performs highly accurate shape abnormality detection by eliminating random noise.

In the shape abnormality detecting device of the present invention, in which the light projecting means has a single light source and the light branching means, the intensity change of the inspection light due to the change of the brightness of the light source is substantially different between the inspection lights. Since they are the same, the intensities of the inspection lights are maintained substantially the same, and a situation in which the intensities of the inspection lights are extremely different is prevented.
Therefore, according to this device, the effect of integrating the electric signals can be reliably obtained.

In an apparatus in which the light projecting means is provided with a plurality of collimator lenses, since each exit end of the light branching means is located at the focal point of the collimator lens, each inspection light exiting from the exit end is substantially formed by the collimator lens. It is made into a parallel light beam.
As a result, the light projecting means emits the inspection light of parallel light flux. When the inspection light of the substantially parallel light flux is used, the light density of the inspection light tends to be constant at the irradiation position on the measurement line. Therefore, according to this apparatus, even if a minute vibration occurs in the columnar body in a direction intersecting with the inspection light, the inspection light is shielded by the columnar body unless the abnormal shape of the columnar body is irradiated with the inspection light. There is no significant change in the amount of light. As a result, noise is less likely to occur in the electric signal output by the light receiving means, and it is possible to perform suitable shape abnormality detection.

In an apparatus in which the light splitting means is provided with a plurality of optical fibers to which light from a single light source enters from one end, the light from the light source is split by entering the light from the light source into each optical fiber. A plurality of inspection lights are formed and emitted from the other end of each optical fiber. By appropriately disposing the light incident end of each optical fiber with respect to the light source, a plurality of inspection lights having substantially the same intensity are formed. Since the optical fiber is used, each inspection light has a substantially uniform light density. Therefore, according to this apparatus, even if a minute vibration occurs in the columnar body in a direction intersecting with the inspection light, the inspection light is shielded by the columnar body unless the abnormal shape of the columnar body is irradiated with the inspection light. A large change does not occur in the amount of light, and as a result, noise is less likely to occur in the electric signal output by the light receiving means, so that suitable shape abnormality detection is performed.

Similarly, the light branching means is an incident side optical fiber,
Even in the device including the light branching portion and the emission side optical fiber, each inspection light has a substantially uniform light density because the optical fiber is used. For this reason, even in the case of this apparatus, even if a minute vibration of the columnar body occurs, a large change does not occur in the light amount of the inspection light shielded by the columnar body, and noise hardly occurs in the electric signal output by the light receiving unit. ,
Suitable shape abnormality detection is performed.

In an apparatus in which the light receiving means has a plurality of light receiving portions facing the respective output ends of the light branching means, the telegraph signals output by the respective light receiving portions are input to the signal processing means,
It is integrated as described above. On the basis of the integrated electric signal thus obtained, the abnormality determining means detects only the pulse corresponding to the shape abnormality in the same manner as described above, so that highly accurate shape abnormality detection excluding random noise is performed.

[0029]

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements will be denoted by the same reference symbols, without redundant description.
Further, the dimensional ratios in the drawings do not always match those described.

In this embodiment, an abnormality in the surface shape of the optical fiber, which is one of the columnar bodies, is detected. The optical fiber to be measured is a bare fiber made of quartz glass having a circular cross section with a diameter of 125 μm, coated with an ultraviolet curable resin (UV resin), and further coated with a colored layer made of white UV ink. And is an optical fiber colored core wire having a circular cross section with a diameter of 250 μm.

A normal optical fiber is required to have a uniform outer diameter in the longitudinal direction. However, if the coating conditions change during the coating of the colored layer, abnormal shapes such as convex portions and concave portions occur on the surface of the colored layer. In this embodiment, such an abnormal surface shape of the optical fiber is detected.

FIG. 1 is an overall configuration diagram showing a shape abnormality detecting apparatus of this embodiment. The shape abnormality detection device of this embodiment is
The light projecting device 58, the light projecting side slit plate 50, the light receiving side slit plate 52, the photodetectors 36 and 38, the signal processing unit 60, and the abnormality determination unit 48.

The light projecting device 58 includes a light source 10 and an optical fiber 1.
2 and 18, and collimator lenses 22 and 24. As the light source 10, in addition to a tungsten lamp or a halogen lamp, a semiconductor laser light source such as an LD (laser diode) having high output light power and a long life, or an LED (light emitting diode) can be used. The optical fibers 12 and 18 guide the inspection light from the single light source 10. The incident end 13 of the optical fiber 12 and the incident end 19 of the optical fiber 18 are both arranged in the vicinity of the light source 10, and the light emitted from the light source 10 is incident on the incident end 13,
The light is incident on the optical fibers 12 and 18 via 19, respectively. If the incident ends 13 and 19 are sufficiently close to each other and the positional relationship between the light source 10 and the incident ends 13 and 19 is appropriately set, the incident light amount on the optical fiber 12 and the incident light amount on the optical fiber 18 are substantially the same. Can be

The collimator lens 22 includes the optical fiber 12
Is disposed at a position with its emission end 14 as the focal point.
Similarly, the collimator lens 24 is also arranged at the position where the emitting end 20 of the optical fiber 18 is the focal point. Therefore, when the light emitted from the optical fibers 12 and 18 enters the collimator lenses 22 and 24, respectively, a parallel light flux is emitted from each collimator lens. The light projecting device 58 is
This parallel light flux is output as inspection light.

When the portion of the light projecting device 58 where the inspection light is emitted is a light emitting portion, the light emitting side slit plate 50 is arranged so as to face the light emitting portion. Emitter side slit plate 50
Has elongated slits 28 and 30 in a direction perpendicular to the plane of the drawing. The slits 28 and 30 are provided to face the collimator lenses 22 and 24 of the light projecting device 58, respectively. These slits 28 and 30 are for preventing light other than the inspection light from entering the optical path of the inspection light.

The light receiving side slit plate 52 is arranged so as to face the light projecting side slit plate 50. Light receiving side slit plate 5
2 has elongated slits 32 and 34 in a direction perpendicular to the plane of the drawing, the slit 32 being the slit 28 of the light projecting side slit plate 50, and the slit 34 being the light projecting side slit plate 5.
It is provided at a position facing each of the 0 slits 30. These slits 32 and 34 are used for the photodetector 3
6 and 38 prevent light other than the inspection light from being received. It should be noted that the light-projecting-side slit plate 50 and the light-receiving-side slit plate 52 are preferably provided to stabilize the light flux, but they are not necessary.

The two inspection lights 54 and 56 which have respectively passed through the slits 28 and 30 travel in directions substantially parallel to each other. In the shape abnormality detecting method of the present embodiment, the detection is performed while moving the optical fiber 1 to be measured along a longitudinal direction on a predetermined measurement line. In this embodiment, as shown in FIG. 1, a line 62 which is a straight line perpendicular to the inspection lights 54 and 56 and which is located substantially in the middle of the light-projecting side slit plate 50 and the light-receiving side slit plate 52 is used as the measurement line. . Inspection light 5
4 and 56 are respectively irradiated to predetermined positions on the measurement line 62.

The photodetector 36 is arranged at a position facing the light emitting portion of the light projecting device 58 with the slits 28 and 32 interposed therebetween. The same applies to the photodetector 38, which has slits 30 and 3
It is arranged at a position facing the light emitting portion of the light projecting device 58 with the light emitting device 4 in between. The photodetector 36 includes slits 28 and 32.
The inspection light 54 that has passed through is detected, and the photodetector 38 detects the inspection light 56 that has passed through the slits 30 and 34.

The signal processing unit 60 includes amplifiers 40 and 42,
The delay time calculation circuit 44 and the integration circuit 46 are included. The amplifier 40 is connected to the photodetector 36 and amplifies the output signal of the photodetector 36. Similarly, the amplifier 42 is connected to the photodetector 38 and amplifies its output signal. The delay time calculation circuit 44 includes the moving speed information 45 of the optical fiber 1 inputted from the outside and the slit 3
2 on the measurement line based on the distance between the slit 2 and the slit 34.
The same portion of the optical fiber 1 that moves the inspection light 54, 56
The difference between the times of passing the irradiation positions of is calculated. An integrating circuit 46 is connected to the amplifiers 40 and 42 and the delay time calculating circuit 44. The integrating circuit 46 integrates the output signal of the amplifier 40 and the output signal of the amplifier 42 while performing correction to match the time when the same portion of the optical fiber 1 is measured based on the output signal of the delay time calculating circuit 44. . An abnormality determining section 48 is connected to the integrating circuit 46, and the abnormality determining section 48 determines the presence or absence of a shape abnormality of the optical fiber 1 based on the output signal of the integrating circuit 46.

Next, a method for detecting the shape abnormality of the optical fiber 1 by the apparatus of FIG. 1 will be described. First, measurement line 6
The light source 10 is caused to emit light while the optical fiber 1 is moved in the longitudinal direction on the optical fiber 2 to cause the light projecting device 58 to output two inspection lights.

More specifically, the light emitted from the light source 10 propagates through the optical fibers 12 and 18, and becomes collimated light beams by the collimator lenses 22 and 24. In this embodiment, the parallel light flux emitted from the collimator lens 22 and the parallel light flux emitted from the collimator lens 24 have substantially the same light intensity. In the present embodiment, the abnormal shape of the optical fiber 1 is detected by using this parallel light flux as the inspection light.

Inspection lights 54 and 5 emitted from the light projecting device 58.
6 is irradiated to the light-projecting side slit plate 50. The inspection light 54 that has passed through the slit 28 and the inspection light 56 that has passed through the slit 30 are applied to the optical fiber 1 moving on the measurement line 62.

FIG. 2 is a diagram showing irradiation positions 64 and 66 of the inspection lights 54 and 56 on the measurement line 62. Since the optical fiber 1 moves on the measurement line 62, each part of the optical fiber 1 sequentially passes through the irradiation positions 64 and 66 and receives the inspection lights 54 and 56. In FIG. 2, d indicates the distance between the slits 32 and 34 (which is almost equal to the distance between the inspection lights 54 and 56), and v indicates the moving speed of the optical fiber 1.

Of the inspection lights 54 and 56, the lights not shielded by the optical fiber 1 are respectively the light receiving side slit plate 52.
Is irradiated. Of the inspection light 54 that has not been blocked by the optical fiber 1, the inspection light 54 that has passed through the slit 32 is the photodetector 3
It is received by 6. Similarly, the inspection light 56 that is not blocked by the optical fiber 1 and passes through the slit 34 is received by the photodetector 38.

The photodetectors 36 and 38 are connected to the inspection light 5 received.
The electric signals of the levels corresponding to the light intensities of 4 and 56 are output respectively. The output signals of the photodetectors 36 and 38 are amplified by amplifiers 40 and 42, respectively, and then input to the integrating circuit 46.

FIG. 3 is a diagram showing time waveforms of two electric signals input to the integrating circuit 46. Is a time waveform of the output signal of the amplifier 40, and corresponds to the time waveform of the light intensity of the component of the inspection light 54 that is not blocked by the optical fiber 1. Similarly, is the time waveform of the output signal of the amplifier 42, and corresponds to the time waveform of the light intensity of the component of the inspection light 56 that is not blocked by the optical fiber 1.

As shown in FIG. 1, when the convex portion 2 is present on the surface at one place of the optical fiber 1, the convex portion 2 moves along with the movement of the optical fiber 1 and the irradiation position of the inspection lights 54 and 56 ( 2), the amount of inspection light blocked by the optical fiber 1 increases. Therefore, at the time when the convex portion 2 passes each irradiation position of the inspection lights 54 and 56, the pulse-like level reduction occurs in the output signals of the amplifiers 40 and 42, respectively. Pulses denoted by reference numerals 80 and 81 in FIG. 3 are reductions in light intensity due to the convex portions 2. Since there is a difference in the time when the convex portion 2 crosses the irradiation position of the inspection lights 54 and 56, there is a difference between the time when the pulse 80 is generated and the time when the pulse 81 is generated even though both are pulses caused by the convex portion 2. There is.

Pulses 90 to 92 appear in addition to the pulses 80 and 81, but these are noises unrelated to the convex portion 2. Such noise occurs when the optical fiber 1 vibrates, or when suspended dust in the atmosphere crosses the inspection light and shields or reflects the inspection light.
The pulse amplitudes of the noise pulses 90 to 92 are substantially the same as the pulse amplitudes of the pulses 80 and 81 caused by the convex portion 2.

The noise due to the vibration of the optical fiber 1 is indicated by reference numeral 90 and by reference numeral 91.
Since the vibration is generated in the entire optical fiber 1, these noises are simultaneously detected by the inspection lights 54 and 56. On the other hand, noise due to airborne dust in the atmosphere is usually detected by one inspection light but not by the other detection light. This is because the suspended dust moves in a random manner, and crossing one inspection light beam does not necessarily cross the other inspection light beam. Such noise is called random noise. In the present embodiment, what is indicated by reference numeral 92 is random noise, which does not appear in.

In the integrating circuit 46, the convex portion 2 has inspection lights 54, 5
Correction is performed so that the times at which the irradiation positions of 6 cross each other are matched, and are integrated. The delay time calculation circuit 44
When the moving speed information 45 of the optical fiber 1 is input from the outside, the moving speed v of the optical fiber 1 and the light receiving side slit 32
The difference t between the time when one portion of the optical fiber 1 passes the irradiation position of the inspection light 54 and the time when the optical fiber 1 passes the irradiation position of the inspection light 56 is calculated based on the interval d between the positions 34 and 34. This time difference t
Is calculated as t = d / v. Delay time calculation circuit 44
Inputs this time difference information to the integrating circuit 46.

The integrating circuit 46 has a built-in delay circuit,
This delay circuit delays the output signal of the amplifier 40 by the time difference t described above by the time difference t described above. The integrating circuit 46 is
The output signal of the amplifier 40 and the output signal of the amplifier 42 delayed in this way are integrated.

FIG. 4 is a diagram showing the integration of signals by the integration circuit 46. ′ Is the delayed output signal of the amplifier 40 and is the output signal of the amplifier 42. And
What is indicated by '+' is an electric signal obtained by integrating 'and. The integrating circuit 46 outputs this integrated electrical signal.

By correcting the time difference and integrating the two electric signals (and in FIG. 3) corresponding to the time waveforms of the light intensities of the inspection lights 54 and 56 respectively, the integrated electric signals of FIG. A pulse 82 in which pulses 80 and 81 resulting from the convex portion 2 of the fiber 1 are integrated appears. Since the noise pulses 90 and 91 and the random noise pulse 92 are not integrated unless the times happen to coincide due to the time difference correction, the amplitude of the pulse 82 corresponding to the convex portion 2 of the optical fiber 1 is that of the noise pulses 90 to 92. It is almost twice the amplitude.
This improves S / N.

The integrated electric signal output from the integration circuit 46 is input to the shape abnormality determination unit 48. The shape abnormality determination unit 48 outputs a determination pulse signal when the level of the integrated electric signal falls below a preset threshold value. As shown in FIG. 4, since the threshold value is set to a value between the pulse top level of the pulse 82 and the pulse top levels of the noise pulses 90 to 92, the shape abnormality determining unit 48 causes the shape abnormality of the optical fiber 1 to occur. Only this is detected and a judgment pulse signal is output. Thereby, the shape abnormality can be detected with high accuracy by distinguishing the pulse corresponding to the shape abnormality from the random noise pulse.

The above threshold value can be determined by performing a trial waveform measurement in advance and measuring the amplitude of a noise pulse or a pulse corresponding to a shape abnormality.

By separately measuring which part of the optical fiber 1 passes the irradiation position of the inspection light 56, the position of the irradiation position of the inspection light 56 at the time when the determination pulse signal is output is obtained. be able to. This is where the shape abnormality occurs. Further, if the reference time and the location of the optical fiber 1 that passes through the irradiation position of the inspection light 56 at this reference time are obtained in advance, the time when the determination pulse signal is output and the moving speed of the optical fiber 1 are determined. Based on this, it is possible to find the location of the abnormal shape.

In the above description, the convex shape abnormality occurs on the columnar body, but a concave portion may occur on the surface of the columnar body. In this case, the light quantity of the inspection light blocked by the columnar body is reduced, so that a pulse-like level increase corresponding to the concave portion appears in the electric signal corresponding to each inspection light. Further, contrary to the above-described embodiment, noise pulses that increase the light intensity of the inspection light may be generated.

In such a case, the threshold value may be set to a value between the pulse top level of the pulse corresponding to the recess appearing in the integrated electric signal and the pulse top level of the noise pulse. By setting the shape abnormality determination unit 48 to output a determination pulse signal when the level of the integrated electric signal exceeds this threshold value, it is possible to detect the recessed shape abnormality.

Normally, in order to detect both a convex shape abnormality and a concave shape abnormality, two threshold values having different levels are set to detect the shape abnormality.
The high level threshold is for detecting a concave shape abnormality, and the low level threshold is for determining a convex shape abnormality. The shape abnormality determining unit determines whether the first abnormality occurs when the level of the integrated electrical signal falls below the low level threshold value.
When the determination pulse signal of No. 2 exceeds the high level threshold value, the second determination pulse signal is output. First
If the judgment pulse signal and the second judgment pulse signal can be distinguished from each other by making the pulse amplitudes different, it is possible to predict to some extent what kind of shape abnormality.

As described above, according to the shape abnormality detecting method of the present embodiment, since the shape abnormality of the optical fiber can be detected separately from the random noise, the detection can be performed with higher accuracy than the conventional one. is there.

The shape abnormality detecting method of this embodiment is performed by irradiating the optical fiber, which is wound around the bobbin and moving, with the inspection light after the secondary coating is applied in the manufacturing process of the optical fiber. Can be executed. In this case, by using the winding meter attached to the bobbin, the location of the optical fiber that passes through the irradiation position of the inspection light at the time when the determination pulse signal is output can be obtained.

Next, in this embodiment, the single light source 10 is used.
The reason why the optical fiber is adopted as a means for branching the light from the light source 10 will be explained.

First, for comparison with this embodiment, consider a case where a light source is prepared for each inspection light instead of using a single light source. The shape abnormality detection of the present invention can be sufficiently performed by such a method, but in this case, the stability of the light source becomes important. That is, since the sensitivity of the photodetector changes according to the light intensity of the inspection light, when the relative brightness of each light source changes due to the instability of each light source and the difference in the light intensity of each inspection light increases, the light detection The amplitude of the pulse corresponding to the shape anomaly appearing in the output signal of the instrument also greatly differs for each photodetection. In such a case, there is a possibility that the effect of signal integration is not sufficiently obtained such that the pulse amplitude hardly increases even if integration is performed, and it is difficult to distinguish from noise.

Since the situation is the same in the conventional double beam method, as a remedy, the light is split from a single light source to form two split lights, and the split light is used as the test light. A method for suppressing the difference in light intensity has been devised. For example, “Spectral Measurement and Spectrophotometer” (Kazuo Shibata, Kodansha Scientific, 2nd printing, August 1, 1979), pages 96 to 99, describes a single light source in a double-beam type self-recording spectrophotometer. Means for splitting the light are disclosed.

It is sufficiently possible to apply such a method to the present invention. However, in such a method, an optical system is assembled with a prism or the like, so that there are drawbacks such as complicated design of the optical system and large size of the device, and it is difficult to realize a compact shape abnormality detection device. is there. There is also a limitation that it is not possible to form three or more branched lights.

In this embodiment, as a more preferable mode of the method of branching the light from a single light source, as shown in FIG.
In the vicinity of the light source 10, the incident ends 13 of the optical fibers 12 and 18,
19 is arranged to split the light and form the inspection light. This method is suitable when the light source 10 has a large light emitting surface such as a tungsten lamp or a halogen lamp. According to this method, it is easy to design the optical system and also to make the optical system compact.
Furthermore, according to this method, it is easy to convert the light from the light source 10 into three or more branched lights.

In this embodiment, the light from the light source 10 is split into two and used as the inspection light. However, if the number of inspection lights is increased, the effect of signal integration is enhanced, so that more accurate shape abnormality detection is possible. Becomes

FIG. 5 is a diagram showing a shape abnormality detecting apparatus which uses, as inspection light, light obtained by splitting light from the light source 10 into three by an optical fiber. Most of the structure of this device is the same as that of the device of FIG. 1, so only a brief description will be given.

The light projecting device 58 shown in FIG. 5 includes three optical fibers 12, 15 and 18. The incident end 16 of the optical fiber 15 is arranged in the vicinity of the light source 10 similarly to the incident ends 13 and 19 of the optical fibers 12 and 18, and the optical fiber 1
The exit end 17 of 5 is located at the focal point of the collimator lens 23.

FIG. 6 is a diagram showing irradiation positions 64 to 66 of the inspection lights 54 to 56 on the measurement line 62. Each part of the optical fiber 1 moving on the measurement line 62 sequentially passes through the irradiation positions 64 to 66 and is sequentially irradiated with the inspection lights 54 to 56. In FIG. 6, d ₁ is the distance between the slits 32 and 33 (this is the inspection light 54 and 55).
Is almost equal to the interval. ), D ₂ is slits 33 and 34
(Which is approximately equal to the spacing between the inspection lights 55 and 56), and v indicates the moving speed of the optical fiber 1.

Similar to the inspection lights 54 and 56, of the inspection lights 55 that have passed through the projection side slit 29, those not blocked by the optical fiber 1 pass through the reception side slit 33 and are detected by the photodetector 37. It

FIG. 7 is a diagram showing the time waveforms of the output signals of the amplifiers 40 to 42 and the signals obtained by correcting the time difference and integrating these signals. Is the time waveform of the output signal of the amplifier 40, is the time waveform of the output signal of the amplifier 41, and is the time waveform of the output signal of the amplifier 42. Pulse 83-85
Corresponds to the convex portion 2 of the optical fiber 1. Also,
The pulses 95, 97 and 98 are noises due to vibration of the optical fiber 1 and the pulses 93, 94, 96 and 99 are random noises due to suspended dust and the like.

The delay time calculation circuit 44 of this device is configured to detect the moving speed v of the optical fiber 1 and the slits 32 and 3 on the light receiving side.
Distance d ₁ and the light receiving side slit 33 3 and 34 spacing d ₂ of
Based on the above, the difference t ₁ between the time when one position of the optical fiber 1 passes the irradiation position of the inspection light 54 and the time when the irradiation position of the inspection light 55 passes, and one position of the optical fiber 1 passes the inspection light 55.
The difference t ₂ between the time of passing the irradiation position of 1 and the time of passing the irradiation position of the inspection light 56 is calculated. The time difference t ₁ is t ₁ =
It is obtained like d ₁ / v. The time difference t ₂ is t ₂ = d ₂ /
It is obtained like v. The delay time calculation circuit 44 inputs this time difference information to the integration circuit 46.

The delay circuit incorporated in the integrating circuit 46 delays the output signal of the amplifier 40 by the time of (t ₁ + t ₂ ), and delays the output signal of the amplifier 41 by the time of t ₂ . The integrating circuit 46 integrates the output signal of the amplifier 40, the output signal of the amplifier 41, and the output signal of the amplifier 42 which are delayed in this way.

What is indicated by "+" + in FIG. 7 is an integrated electric signal. The amplitude of the pulse 86 corresponding to the convex portion 2 of the optical fiber 1 is almost three times the amplitude of the noise pulses 94 to 99 by integrating the three electric signals corresponding to the time waveforms of the light intensity of each inspection light. Become. The amplitude difference becomes larger and the S / N becomes higher than when the two inspection lights are integrated. In addition, for example, by setting the threshold value for the shape abnormality determination to a value between the pulse top level of the pulse 86 and the level twice the pulse top of the noise pulse, it is possible to accidentally generate two values when integrating the electric signals. Even if two noise pulses are integrated, it is not erroneously determined as a shape abnormality. Therefore, according to the apparatus of FIG. 5, the abnormal shape of the optical fiber 1 can be detected with higher accuracy.

As the number of inspection lights is increased, it becomes easier to prevent erroneous determination of a shape abnormality and more accurate detection becomes possible, but increase in price and complexity of design of delay circuit system and optical system are taken into consideration. Then, it is considered appropriate to set the number of inspection lights to about 2 to 5.

In addition to the above method, the optical branching can be performed by the method shown in FIG. in this way,
The incident end 75 of the optical fiber 70 is arranged in the vicinity of the single light source 10, and the light is guided from the light source 10 through the single optical fiber 70. A plurality of optical fibers 71 to 73 are connected to the optical fiber 70 via a branch portion 74. The branching unit 74 splits the incident light into three lights with almost equal light intensities. As the branch portion 74, a thin film optical waveguide or the like can be used. The branched lights are optical fibers 71 to 7 respectively.
3 propagates to reach each emission end (not shown).
These emitting ends are arranged at the focal points of the collimator lenses as in the device of FIG.

By the above method, the light from the light source 10 can be branched to form three inspection lights. Also with this method, it is easy to design the optical system and make the optical system compact. Since this method guides light from the light source 10 with a single optical fiber, it is particularly suitable when a semiconductor laser light source such as an LD or a light source having a small light emitting surface such as an LED is used.

The method for branching the light from the light source with the optical fiber described above is extremely uniform as compared with the case where one light source is arranged at the focal point of each collimator lens without using the optical fiber. There is an advantage that a parallel light flux having a density can be obtained. From the viewpoint of achieving uniform light density, it is desirable that the total length of the optical fiber is long, but if it is too long, the optical fiber itself will cause a loss of light intensity due to transmission loss, so the length of the optical fiber is from the light source to the collimator lens. It is desirable that the distance is about 5 to 50 cm.
In addition, a bundle fiber having a plurality of cores may be used as the optical fiber in order to increase the amount of light guided from the light source.

The reason why the collimator lens is used to form the inspection light of the substantially parallel light flux in the present embodiment is that each inspection light has a uniform light density. When such inspection light is used, even when a slight vibration occurs in the optical fiber to be measured in a direction intersecting with the inspection light, the light amount of the inspection light shielded by the optical fiber does not significantly change. As a result, noise is less likely to occur in the electric signal output by the light receiving means, and it is possible to perform suitable shape abnormality detection.

The present inventors intentionally changed the coating conditions when coating the colored layer of the optical fiber to form a plurality of wavy irregularities on the surface of the colored layer, and wound the optical fiber at a linear velocity of 10 m / min. While on the measurement line 62 of the device of FIG.
It was moved by m to detect abnormal shape. The unevenness is formed at 10 points on the optical fiber 1, and its amplitude is 15 μm. When detection was performed in the same manner as above, detection was performed at 10 times or more S / N in all 10 locations, and there was no other detection (erroneous detection).

For comparison, a conventional double-beam type shape measuring apparatus was used to perform measurement under the same conditions as in the example, and detection was performed at a S / N ratio of about 5 times at 10 locations. Other than this, there were 6 false detections. The cause of the erroneous detection was 4 times the airborne dust in the atmosphere and 2 times the vibration of the optical fiber.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments and various modifications can be made. For example, it suffices that the columnar body to be measured moves relative to the inspection light, and it is also possible to move the shape abnormality detection device to perform detection, contrary to the embodiment.

[0084]

As described above in detail, in the shape abnormality detecting method of the present invention, the time waveforms measured for each inspection light are integrated, and the shape abnormality is detected based on the obtained integrated time waveform. Therefore, it is possible to easily distinguish the pulse corresponding to the shape abnormality from the noise pulse, and it is possible to perform the highly accurate shape abnormality detection excluding the random noise.

When the inspection light formed by branching the light from the single light source is used, the intensities of the respective inspection lights are maintained substantially the same, so that the effect of integrating the time waveforms can be surely obtained. Suitable shape abnormality detection is possible.

When the inspection light of the substantially parallel light flux is used, the light density of the inspection light is likely to be constant at the irradiation position on the measurement line, so that noise is less likely to occur in the measured time waveform and suitable shape abnormality detection can be performed. It can be carried out.

Further, according to the shape abnormality detecting apparatus of the present invention, the electric signals corresponding to the respective inspection lights are integrated while the correction is made so that the time when one portion of the columnar body passes each irradiation position of the inspection light is adjusted. Since the shape abnormality is detected based on the obtained integrated electric signal, it is possible to detect the shape abnormality with high accuracy without random noise.

In the shape anomaly detecting device of the present invention, in which the light projecting means is provided with a single light source and the light branching means, the intensities of the respective inspection lights are maintained substantially the same, and therefore the electrical signals are integrated. It is possible to surely obtain, and it is possible to suitably detect the shape abnormality.

In an apparatus in which the light projecting means is provided with a plurality of collimator lenses, the test light of the substantially parallel light flux is irradiated, and the light density of the test light tends to be constant at the irradiation position on the measurement line. Noise is less likely to occur in the output electrical signal, and suitable shape abnormality detection can be performed.

In an apparatus in which the light branching means is provided with a plurality of optical fibers into which light from a single light source is incident from one end, the light branched by the optical fibers is used as the inspection light, so that each inspection light is substantially It has a uniform light density. As a result, noise is less likely to occur in the electric signal output by the light receiving unit, and thus it is possible to perform suitable shape abnormality detection.

In the device in which the optical branching means includes the incident side optical fiber, the optical branching part and the emitting side optical fiber, the light branched by the optical fiber is used as the inspection light, so that noise is generated in the electric signal output by the light receiving means. This makes it difficult to perform suitable shape abnormality detection.

In an apparatus in which the light receiving means has a plurality of light receiving portions facing the respective output ends of the light branching means, the telegraph signals output by the respective light receiving portions are input to the signal processing means and integrated, so that random noise is generated. It is possible to perform highly accurate shape abnormality detection that excludes.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing a shape abnormality detection device of the present embodiment.

FIG. 2 is a diagram showing irradiation positions 64 and 66 of inspection lights 54 and 56 on a measurement line 62.

FIG. 3 is a diagram showing time waveforms of two electric signals input to an integrating circuit 46.

FIG. 4 is a diagram showing integration of signals by an integration circuit 46.

FIG. 5 is a diagram showing a shape abnormality detection device that uses, as inspection light, light obtained by branching light from a light source 10 into three by an optical fiber.

6 is a diagram showing irradiation positions 64-66 of inspection lights 54-56 on the measurement line 62. FIG.

FIG. 7 is a diagram showing time waveforms of output signals of amplifiers 40 to 42 and signals obtained by correcting the time difference and integrating these signals.

FIG. 8 is a diagram showing a method of branching the light from the light source 10.

FIG. 9A is a diagram showing a conventional method for detecting an abnormal surface shape of a columnar body, and FIG. 9B is a diagram showing the time of the light intensity of a component of the parallel light flux that is not shielded by the columnar body. It is a figure which shows a waveform.

FIG. 10A is a diagram showing a double beam method,
(B) is a diagram showing cancellation of noises 90 and 91 by the double beam method.

FIG. 11 is a diagram illustrating a double beam method when random noise 92 occurs.

[Explanation of symbols]

1 ... Optical fiber to be measured, 2 ... Convex portion, 10 ... Light source, 1
2 and 18 ... Optical fiber, 22 and 24 ... Collimator lens, 36 and 38 ... Photodetector, 40 and 42 ... Amplifier, 44 ... Delay time calculation circuit, 46 ... Integration circuit, 48 ...
Abnormality determination unit, 58 ... Projector, 60 ... Signal processing unit, 62
… Measurement line.

Claims (7)

[Claims] 1. A columnar body to be measured with respect to the inspection light on the measurement line while irradiating a plurality of irradiation positions on a predetermined measurement line with a plurality of inspection lights traveling in directions substantially parallel to each other. And a second step of detecting a component of the inspection light that is not blocked by the columnar body, and measuring the time waveform of the light intensity of this component for each inspection light. The columnar bodies are integrated on the basis of the time waveforms obtained by integrating the time waveforms measured for the respective inspection lights while correcting the time when one position of the columnar body passes each irradiation position. A third step of detecting an abnormal shape of the body, and a method of detecting an abnormal shape of the columnar body. 2. The first step is a step of irradiating the irradiation position with a plurality of inspection lights formed by branching light from a single light source and having substantially the same light intensity. The shape abnormality detection method according to claim 1, wherein 3. A columnar column that moves relatively on the measurement line relative to the inspection light by irradiating a plurality of irradiation positions on a predetermined measurement line with a plurality of inspection lights that travel in directions substantially parallel to each other. A device for detecting an abnormality in the surface shape of a body, comprising: a light projecting unit for irradiating each of the inspection lights to each of the irradiation positions; and a light receiving unit that faces the light projecting unit with the measurement line interposed therebetween. , Detecting each of the inspection light and outputting a plurality of electric signals corresponding to the time waveform of the light intensity of each of the inspection light, and the time when one portion of the columnar body passes through each of the irradiation positions is matched. A signal processing unit that integrates the plurality of electric signals while performing the correction, and outputs the obtained integrated electric signal; and an abnormality determination unit that detects a shape abnormality of the columnar body based on the integrated electric signal, Prepare Shape abnormality detecting device of the columnar body. 4. The light projecting means splits a single light source and a plurality of inspection lights having substantially the same light intensity by splitting light emitted from the light source, and emitting a plurality of inspection lights. The shape abnormality detecting device according to claim 3, further comprising: a light branching unit that emits light from each of the ends. 5. The light branching means comprises a plurality of optical fibers into which light from the single light source enters from one end thereof, and the other end of each of the optical fibers serves as the emitting end. The shape abnormality detection device according to claim 4, wherein 6. The light splitting means splits an incident side optical fiber into which light from the single light source is incident and a light branching from the incident side optical fiber to form the inspection light. 5. A plurality of parts and a plurality of emission side optical fibers on which the respective inspection lights are respectively incident, and the other ends of the respective emission side optical fibers are the emission ends, respectively. Abnormal shape detection device. 7. The light-receiving means is a plurality of light-receiving parts facing the respective emission ends of the light branching means, detects the inspection light emitted from the emission ends, and detects the light intensity of each inspection light. The shape abnormality detecting device according to claim 4, further comprising: a device that outputs an electric signal corresponding to a time waveform.