JPH04127564U - defect detector - Google Patents

Abstract

(57) [Summary] [Purpose] The purpose is to provide a defect detector that can uniformly irradiate a sufficient amount of light within an irradiation range and can accurately detect defects in a detection target. [Structure] The light emitting fibers 21 to 29 are arranged in a staggered manner as shown in the figure. That is, by positioning the light emitting fiber 26 in the gap formed near the contact portion P1 of the light emitting fibers 21 and 22, the weak light amount at the contact portion P1 is compensated for and the irradiation efficiency is improved. The light receiving section has a similar structure to ensure a sufficient amount of light reception. In addition, when detecting textiles, attach polarizing filters that transmit light components at a predetermined angle to the light emitting and receiving sides, and detect changes in the amount of received light based on changes in the polarization angle due to diffusion during transmission. Good too.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

The present invention relates to the structure of a defect detector equipped with a fiber, and in particular to a light emitting fiber and a receiving fiber. This is an idea regarding the arrangement structure of optical fibers.

0002

[Conventional technology]

For defect detection, for example, light is used to distinguish and recognize defects such as holes in sheet materials, etc. There is a scientific sensor. FIG. 5 is a front view of the light emitting section of the sensor head section, and shows a plurality of light emitting sections. Fibers 71, 72, 73, 74, and 75 are integrally formed. Each of these floodlights Irradiation light is projected from the fiber toward a sheet material (not shown) to be detected. The reflected light or transmitted light is received by a separately provided light receiving section (not shown). still Similarly, the light receiving section is formed by arranging a plurality of light receiving fibers.

0003 While performing such light emitting and receiving operations, the sensor head moves over the sheet material in the direction of arrow 90. Move and scan. Then, the amount of light received from the light receiving section is given to a predetermined detection circuit, The presence or absence of light reception and changes in light intensity are monitored. Depending on whether the sheet material has holes or other defects The amount of light received changes, and the detection circuit determines whether there is a defect in the sheet material.

0004

[Problem that the idea aims to solve]

The conventional defect detector for sheet materials, etc. described above has the following problems. optical fiber Usually, its cross section is circular, and each light emitting fiber is placed close to each other. However, at the contact point P9, only a weaker amount of light can be irradiated than at the center of the fiber. I can't. For such areas, the amount of light irradiated is inherently low, so the sheet Even if a hole or the like is formed in the material, the amount of received light and the change in the amount of light will be relatively small.

[0005] As mentioned above, this defect detector identifies defects based on the presence or absence of light reception and changes in light intensity. Therefore, if the amount of received light itself decreases, the detection accuracy will decrease. Ru. In particular, if the hole formed in the sheet material is relatively small, it is detected. I can't. Also, in the light receiving section, the area near the contact area of each light receiving fiber is sufficient. It is said that it is not possible to capture the amount of light in the same way, making it impossible to perform accurate detection. cause problems.

[0006] For this reason, the fiber diameter of each fiber is reduced to reduce the irradiation efficiency within the irradiation area H9. It is also possible to improve the rate. However, special fibers with small diameter This creates new problems in that manufacturing costs increase and the cost of the product increases. Also, even if the fiber diameter is made smaller, the light intensity will still be weak near the contact area of each fiber. Therefore, it cannot be said that the above-mentioned problem is fully solved.

[0007] Therefore, the present invention aims to maintain the fiber diameter while providing sufficient light intensity within the irradiation range. It is possible to irradiate uniformly and accurately detect defects on the object to be detected. The purpose of the present invention is to provide a defect detector.

[0008]

[Means to solve the problem]

The defect detector according to the present invention is A light emitting fiber that emits illumination light toward an object to be detected. This occurs near the contact area between the first light emitting fiber and the second light emitting fiber. Each light emitting fiber is arranged so that the third light emitting fiber is located in the gap. light emitting fiber, A light-receiving fiber that receives reflected light or transmitted light from an object to be detected, the fibers being connected to each other. A plurality of fibers are arranged adjacently and near the contact area between the first light receiving fiber and the second light receiving fiber. Each receiving fiber is arranged so that the third receiving fiber is located in the gap created next to it. receiving fiber, Detection that detects the presence or absence of defects in the object to be detected according to changes in the amount of light received by the receiving fiber circuit, It is characterized by having the following.

[0009]

[Effect] In the defect detector according to the present invention, a plurality of light emitting fibers are arranged adjacent to each other. This occurs near the contact area between the first light emitting fiber and the second light emitting fiber. Each light emitting fiber is arranged so that the third light emitting fiber is located in the gap. . A plurality of light receiving fibers are also arranged adjacent to each other, and the light emitting fiber and Similarly, a gap occurs near the contact area between the first receiving fiber and the second receiving fiber. The light-receiving fibers are arranged such that the third light-receiving fiber is located in the third light-receiving fiber.

0010 In this way, by placing the light emitting fiber and light receiving fiber in the gap, It is possible to compensate for the weak amount of irradiation near the contact portion. In other words, in the irradiation area It is possible to average the amount of irradiation light applied to the area and ensure a sufficient amount of light in the entire area.

[0011]

【Example】

An embodiment of the present invention will be described based on the drawings. First, Figure 1A shows the sensor head section. A side view of the light projecting unit 2 is shown. The light emitting unit 2 includes a plurality of light emitting fibers (fiber bundle) 21, 26 etc. are adjacent and integrally formed. Then, from each light emitting fiber, Irradiation light L1 is irradiated toward the sheet material 10 to be emitted, and this transmitted light and reflected light are received. The light is received by a light section (not shown). This light-receiving section also has multiple adjacent light-receiving fibers. It is formed from a fiber bundle) and has almost the same structure as the light projecting section 2.

0012 When performing detection based on transmitted light of the projected irradiation light, the back of the sheet material 10 Position the light receiving section on the surface side, and detect the transmitted light that has passed through the hole in the sheet material 10. to go out. On the other hand, when detecting based on reflected light, the light emitting part is Position the light receiving section on the same side as 2. In this case, the irradiated light will not pass through the hole. Since no reflected light is generated, the amount of received light is reduced, and detection is performed based on this.

[0013] The amount of light received by the light receiving section is captured by a detection circuit, and the presence or absence of light reception and changes in light amount are monitored. A defect in the sheet material 10 is recognized. Note that the sensor formed by the light emitter and light receiver The head section moves and scans the sheet material 10 in the direction of arrow 90 to perform detection.

[0014] FIG. 1B shows a front view of the light projector 2. In this embodiment, the light projector 2 includes a light projector It consists of nine fibers: 21, 22, 23, 24, 25, 26, 27, 28, and 29. For example, the light emitting fiber is inserted into the gap created near the contact portion P1 of the light emitting fibers 21 and 22. Each light emitting fiber is arranged such that the bar 26 is located. In other words, the light emitter Only a weak amount of light can be emitted from the vicinity of the contact point P1 of the fibers 21 and 22, but this contact The approximate center of the light emitting fiber 26 is located in the gap near the contact part P1 to replenish a sufficient amount of light. ing.

[0015] In this way, the amount of irradiation light within the irradiation area H1 is made uniform, and sufficient The amount of irradiation light can be secured. Most fibers are usually 1 mm in diameter. In this invention, the irradiation efficiency can be improved even if the fiber diameter is not 0.5 mm. can be improved. In addition, we temporarily reduced the fiber diameter to 0.5 mm. However, it is not possible to compensate for the weak light intensity near the contact portion of each fiber. vinegar In other words, according to the present invention, while maintaining the fiber diameter, the irradiation area H1 can be more reliably This makes it possible to improve irradiation efficiency.

[0016] The light-receiving fibers in the light-receiving section are arranged in the same way, ensuring sufficient and accurate light reception within the light-receiving range. This allows for accurate light reception. In addition, the light emitting fiber and the light receiving fiber are 9 There may be more or less than books.

[0017] Next, an embodiment of the detection circuit is shown in FIG. The detection circuit 50 includes an amplifier 52 and a comparator 54 and a Schmitt circuit 56. In this embodiment, the transmitted light from the sheet material 10 A circuit that performs detection based on presence or absence will be explained as an example. The light from receiving fiber 4 is amplified 52, and the amplified light reception signal is output. This received light signal is It is applied to a comparator 54 and compared with a preset threshold Th.

[0018] As a result of the comparison, if the received light signal exceeds the threshold value Th, the comparator 54 connects the light receiving fiber The light guided by 4 is transmitted light that has passed through the sheet material 10, and a hole is formed in the sheet material 10. It determines that it has been achieved and outputs a comparison signal. This comparison signal is Schmitt circuit 56 , and one pulse of a predetermined length is output as a defect signal. This lack When a defect signal is output, the occurrence of a defect is recognized, and predetermined processing is then performed. Defect detectors are used to detect defects such as holes in textiles. Also used for However, in this case, the woven fabric has many fine spaces in the yarn itself and in the weave. The irradiated light is not blocked even when there are no defects such as holes in the fabric. It will pass through. For this reason, a sensor head with a structure as shown in Figure 3 is used to It is preferable to detect defects by receiving light.

[0019] A light emitting side polarizing filter 2F is located between the light emitting part 2 and the fabric 15. A light-receiving side polarizing filter 4F and a light-receiving section 4 are located on the back side of the light-receiving side. First, each light emitting The irradiated light L1 from the fiber is projected onto the fabric 15 through this light projection side polarizing filter 2F. Ru. Polarizing filters transmit only specific light components of the received light. For example, in this embodiment, the light emitting side polarizing filter 2F is used for light with a polarization angle of 0 degrees (180 degrees). It shall be transparent to the components. In other words, the fabric 15 is Only the irradiation light L1 processed to have a polarization angle of 0 degrees (180 degrees) is projected.

[0020] When the irradiated light L1 passes through the fabric 15, it is reflected by the weaving threads on the surface and inside of the fabric 15, and is diffused. It will be done. Due to the diffusion effect in this fabric 15, the irradiated light L is processed to 0 degrees (180 degrees). A change occurs in the polarization angle of 1 and is converted into light containing various polarization angles. thus , the irradiated light L1 whose polarization angle has changed is transmitted through the fabric 15 as transmitted light L2, and then is received. The light enters the side polarizing filter 4F. This receiving side polarizing filter 4F is the transmitting side polarizing filter. It is designed to transmit only the light component with almost the same polarization angle as Ta 2F, that is, 0 degrees (180 degrees). It has become.

[0021] Here, the transmitted light L2 is affected by the diffusion effect when passing through the fabric 15 as described above. There is a change in the polarization angle of For this reason, most of the transmitted light L2 is filtered through the polarizing filter on the receiving side. Only the light that is rejected by the 4F and has a polarization angle of 0 degrees (180 degrees) enters the polarizing filter on the receiving side. Pass through filter 4F. Then, the transmitted light L2 transmitted through the polarizing filter 4F on the receiving side is received. The light is received by section 4. In other words, compared to the transmitted light L2 immediately after passing through the fabric 15, the light receiving section 4, transmitted light L2 with a reduced amount of light is received.

[0022] In addition, the transmitting fiber 2, the transmitting side polarizing filter 2F, the receiving side polarizing filter 4F, and the receiving side The fiber 4 moves in the direction of arrow 90 and scans both sides of the fabric 15 for detection. conduct. Next, the diagram shows the situation when the irradiation light L1 is projected onto the hole 19, which is a defective part of the fabric 15. The explanation will be based on 3B.

[0023] The irradiated light L1 projected onto the hole 19 of the fabric 15 passes through the fabric 15 from the hole 19 and is transparent. It enters the light receiving side polarizing filter 4F as the excess light L2. In this case, the transmitted light L2 is transmitted through the fabric 15. Since it is not affected by the diffusion of The light component having the optical angle enters the light-receiving side polarizing filter 4F as it is. vinegar In other words, the transmitted light L2 that has passed through the fabric 15 is polarized on the receiving side while maintaining its light intensity. The light passes through the optical filter 4F and is received by the light receiving section 4.

[0024] As described above, if holes 19 have occurred, if holes 19 have not occurred in the fabric 15, The amount of transmitted light L2 received by the light receiving section 4 increases compared to the case where the light receiving section 4 receives the transmitted light L2. And receiving light The amount of light received by section 4 is taken into the detection circuit, changes in the amount of light are monitored, and the amount of light received is When the amount increases, it is recognized that defects such as holes 19 occur in the fabric 15.

[0025] In addition, as the receiving side polarizing filter 4F, the polarization angle that the transmitting side polarizing filter 2F transmits is Use a polarizing filter with a polarization angle 90 degrees different from that of the You can stay there. In this case, conversely, when detecting a normal location without defects such as holes, the amount of light received is large. However, if a defective location is detected, the amount of light received will decrease.

[0026] FIG. 4 shows the received light signal waveform data of the transmitted light L2 transmitted through the fabric 15. Figure 4A is a woven fabric This is the waveform when detecting the defect-free part of hole 15 (see Figure 3A), and Figure 4B is the waveform when detecting hole 19. This is the waveform data when detected (see FIG. 3B). As shown in Figure 4B, At hole 19 of object 15, a significant change occurs in the waveform data, and a change waveform 19W is formed. Ru. This change waveform W19 is then compared with the threshold Th in the comparator 54. and a comparison signal is output (see FIG. 2).

[0027] A differentiating circuit may also be provided between amplifier 52 and comparator 54 (not shown). slight By installing a branch circuit, the amount of change in the received light signal can be detected and clearer waveform data can be obtained. Obtainable. Therefore, it is possible to improve the detection accuracy. Furthermore, figure The data shown in No. 4 shows that in the experiment, the detection head was placed on the same part of the fabric. The figure was repeatedly scanned back and forth, and the same waveform with a certain width is repeated in the figure. It is shown.

[0028]

[Effect of the idea]

In the defect detector according to the present invention, the light emitting fiber and the light receiving fiber are also connected in the gap. By positioning the The amount of light can be secured. Therefore, the irradiation range can be adjusted while maintaining the fiber diameter. A sufficient amount of light can be uniformly irradiated within the area. In other words, effective lighting Accurate defect detection of the object to be detected is possible by detecting and receiving light, and even defects such as small holes can be detected. Can be reliably detected.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a light projecting section according to an embodiment of a defect detector of the present invention, where A is a side view of the light projecting section and B is a front view of the light projecting section.

FIG. 2 is a diagram showing an embodiment of the detection circuit of the defect detector of the present invention.

FIG. 3 is a diagram showing a head section according to another embodiment of the defect detector of the present invention, in which A is a side view showing a state in which a normal fabric surface is being detected, and B is a side view showing a state in which a normal fabric surface is detected, and B is a fabric surface with holes. FIG.

FIG. 4 is waveform data of a light reception signal from the amplifier shown in FIG. 2, where A is a waveform on a normal fabric surface and B is a waveform on a fabric surface with holes.

FIG. 5 is a front view showing a conventional light projecting section.

[Explanation of symbols]

2... Light emitting part 4... Light receiving part 10... Sheet material 19... Hole L1... Irradiation light P1... Contact part 21, 22, 23, 24, 25, 26, 27, 28, 29...Emission fiber 50...Detection circuit

Claims (1)

[Scope of utility model registration request] Claim 1: A plurality of light emitting fibers that emit irradiation light toward an object to be detected, wherein a plurality of light emitting fibers are arranged adjacent to each other, and a plurality of light emitting fibers are formed near a contact point between a first light emitting fiber and a second light emitting fiber. Each light emitting fiber is arranged so that the third light emitting fiber is located in the gap, and the light receiving fiber receives the reflected light or the transmitted light from the object to be detected, and the light emitting fibers are arranged adjacent to each other. A plurality of light receiving fibers are arranged, and each light receiving fiber is arranged so that a third light receiving fiber is located in a gap created near the contact portion of the first light receiving fiber and the second light receiving fiber. A defect detector comprising: a detection circuit that detects the presence or absence of a defect in an object to be detected according to a change in quantity.