JPH1196812A - Lighting system for detecting defect - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide uniform illumination without unevenness of illumination by projecting illumination light, without illumination unevenness to an object to be inspected by using direct light from linear tube light sources and reflected light from a reflecting plate. SOLUTION: Direct illumination light, projected from a first and a second linear tube light sources 12a, 12b, are outgoing radiated directly out of an aperture 14 and a part of the direct illumination light from the linear tube light sources 12a, 12b is shut off by a reflecting plate 13 and is prevented from being radiated out of the aperture 14. On the other hand, the illumination light from a third linear tube light source 12c is reflected by the reflecting plate 13 and radiated out of the aperture 14. Without overlapping each other, the direct illumination light, which is not reflected by the reflecting plate 13, from the first and the second linear tube light sources 12a, 12b and the reflected illumination light emitted from the linear tube light source 12c and reflected by the reflecting plate 13 are radiated out of the aperture 14. Consequently, illumination light with uniform luminous energy without illumination unevenness is projected through the aperture 14 to a sheet of paper, which is an object to be inspected and the illumination light transmitted through the sheet of paper can be detected by a line sensor or an electronic camera.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illuminating device for illuminating a wide and long product, such as paper, film and fiber, when automatically inspecting the product.

[0002]

2. Description of the Related Art In the process of manufacturing a wide and long product, the presence or absence of a defect such as a hole, foreign matter contamination, or contamination of the product is inspected and confirmed, and a product having no defect is provided on the market. As a method of inspecting these products for defects, visual inspection by an inspector is inefficient, and with the recent development of electronic technology, an automatic and high-speed inspection apparatus has been developed and used.

[0003] Specifically, a description will be given using an example in the papermaking industry. In the manufacture of paper, paper produced from papermaking chips is manufactured in a certain width (several meters) and in a long length (several hundred meters), and the long paper is wound into a roll. taking it. The paper wound in a roll is cut to a required size or printed on a roll of paper and then cut to a predetermined size.

[0004] When the paper is wound into a roll at the time of manufacture, the whole area of the manufactured paper is inspected for the presence or absence of the above-mentioned defect. A process such as cutting off a portion or remanufacturing again when the number of defects is abnormally large is performed.

As this defect inspection method, a method as shown in FIG. 3 is used. In this figure, a part of a casing described later is cut away. In the figure, reference numeral 31 denotes the manufactured paper. The paper 31 is slid on the conveyer and wound up by a roll (not shown) by a roll and a conveyer (not shown). A light source device 32 for projecting illumination light from below the paper 31 sliding on the conveyor is arranged. The light source device 32 has a rectangular box shape, and has a casing 3 having an opening on the upper surface on the paper 31 side.
3, and a plurality of light sources 34a, 34b to 34n such as halogen lamps or incandescent lamps are arranged and mounted in a straight line in a housing 33 thereof.

The illuminating lights 35a, 35b to 35n projected from the light sources 34a to 34n of the light source device 32 project below the paper 31. On the other hand, the illumination light 35a to 35
A line sensor (not shown) or a wide-angle electronic camera (hereinafter, referred to as a transmitted light detection device) is provided on the surface opposite to the surface on which n is projected. The transmitted light detecting device is provided with the light sources 34a to 34a transmitted through the paper 31.
The illumination light 35a to 35n from 4n is detected or imaged. The signal detected or imaged by the transmitted light detection device is binarized by an electronic computer (not shown) or the like, and the signal is analyzed from the binarized signal.
One defective part is recognized and extracted.

That is, when there is a hole in the paper 31 to be inspected, there is a difference in the amount of light from the illuminating lights 35a to 35n transmitted through the hole portion and the portion without the hole. In this case, there is a difference in the amount of transmitted light between the foreign matter-mixed portion and the portion without the foreign matter. Further, when the paper 31 is dirty, there is a difference in the amount of transmitted light between the dirty portion and the portion without the stain. By comparing the signal generated by the transmitted light detection device with a signal of a preset reference light amount, the contents of defects such as holes, inclusion of foreign matter and dirt, The position where the defect exists is determined and recognized.

[0008] Since a halogen lamp or an incandescent lamp is used for the light sources 34a to 34n, generally 5 light sources are used.
It is necessary to install lamps at intervals of 50 mm in a width of 0 m, and the required number of lamps and the power consumption of the lamps also increase. Furthermore, since the heat generated from the lamp is transmitted to the paper, which is an object to be inspected that does not like heat, it is necessary to take measures such as deterioration of the paper quality or addition of a device for dissipating heat of the lamp. is there.

For this reason, recently, an illumination device using a straight tube fluorescent lamp which generates a small amount of heat and can obtain linear illumination light has been used.

An illumination device using the straight tube fluorescent lamp will be described with reference to FIG. The difference between FIG. 3 and FIG. 3 is that only the light source 34 is changed from a halogen lamp or an incandescent lamp to a straight fluorescent lamp.
1 'is paper, 32' is a light source device, 33 'is a housing, 34a'
34n 'indicate a straight tube light source, 35a' to 35n 'indicate illumination light, and 36a' to 36n 'indicate a projection range, and a description thereof will be omitted.

In such a paper inspection apparatus, as shown in FIG. 3, when a halogen lamp or an incandescent lamp is used for the light sources 34a to 34n, for example, illumination light 35a and 35b projected from the light sources 34a and 34b are used. Is the range indicated by reference numerals 36a and 36b in the drawing. When the projection ranges 36a and 36b are set so as not to overlap at the boundary as shown in the figure, the amount of light projected and transmitted on the paper 31 at the boundary decreases, and the projection ranges 26a and 36b overlap. When the setting is made, a difference occurs in the amount of light projected on the paper 31 and the amount of light transmitted through the overlapping portion and the non-overlapping portion of the projection range. That is, unevenness occurs in the amount of light projected on the paper 31, and it is necessary to determine whether the difference in the signal detected by the transmitted light detection device is due to the defective portion or unevenness in the amount of transmitted light. The analysis of the signal detected by the light detection device and the setting of the reference value need to take into account the unevenness of the amount of transmitted light, it takes a long time for the inspection judgment, and when the paper quality is changed, the setting conditions need to be changed each time. There is a problem that unnecessary time and cost are required for automatic defect determination.

Further, as shown in FIG. 4, since the light source 34a 'uses a straight tube fluorescent lamp, the illumination light 35a' to 35n 'projected on the paper 31' is a projection light having a long shape in the tube axis direction. The range is 36a 'to 36n'. This projection range 36a '
And 36b '(shown by a dotted circle in the figure)
As in FIG. 3, the difference in projection and transmission light amount occurs between the boundary portion and the portion other than the boundary portion in the case where the overlap is not performed and the case where the overlap is performed. In other words, by changing the light source from a halogen lamp and an incandescent lamp to a straight tube fluorescent lamp, it is possible to reduce the number of light sources used, the power consumption, and the amount of heat generated from the light source, but to reduce the amount of heat generated from the light source. The problem of uneven projection and transmitted light remains.

[0013]

As described above, the illumination light is projected onto the wide and long object to be inspected, and the illumination light transmitted through the front object to be inspected is detected to detect the defect of the object to be inspected. In the detection and determination device, a plurality of light sources are arranged on a straight line, and when projected onto the object to be inspected, between a boundary portion of a projection range formed by individual light sources adjacent to the light source and a portion other than the boundary. Illumination unevenness occurs due to the difference in light amount. There has been a problem that the uneven lighting may hinder the detection and determination of the defect of the inspection object.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an illuminating device for defect detection which can obtain uniform illumination without uneven illumination.

[0015]

According to the present invention, a plurality of straight tube light sources for projecting illumination light onto an object to be inspected, and the straight tube light sources are arranged and housed in a checkered pattern. A light source housing having an opening for projecting light onto the object to be inspected,
A reflector that reflects illumination light from the straight tube light source, which is arranged and housed on the opening side of the light source housing, among the straight tube light sources arranged and housed in the light source housing; The illumination device for defect detection is configured to project illumination light without uneven illumination onto the object to be inspected by direct light from the light source and reflected light from the reflection plate.

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a partial cross-sectional perspective view showing one embodiment of a defect detection illumination device according to the present invention, and FIG. 2A is a top view as viewed from the direction of arrows AA in FIG. FIG. 2B is a plan view showing the front as viewed from the arrow direction of the BB cutting line in FIG. 1 and FIG. 2C is a plan view showing the side surface as viewed from the arrow direction of the CC cutting line in FIG. The description will be made with reference to these drawings. A first straight tube light source 12a using a straight tube fluorescent lamp inside the bottom surface of a rectangular box type light source housing 11
And the second straight tube light source 12b are housed and mounted so that their tube axes are aligned with each other, and the first and second straight tube light sources 12b are
A predetermined interval is provided between a and 12b. A third straight tube light source 12 is provided on one side of the light source housing 11.
c is parallel to the tube axes of the first and second straight tube light sources 12a, 12b and the first and second straight tube light sources 12a, 12b
It is housed and mounted at a position that fills the space provided by. That is, as shown in the upper surface of FIG. 2A and the front surface of FIG.
Arranged so that the illumination lights from b and 12c overlap. The other side surface of the light source housing 11 is provided with a reflector 13 for reflecting the illumination light from the third straight tube light source 12c above the light source housing 11. This reflector 1
3 has a rectangular reflecting surface, and the longitudinal center line of the reflecting surface is on the center axis of the first and second straight tube light sources 12a and 12b and the third straight tube light source 12c. Is mounted parallel to the center axis of the tube axis. That is, the direct illumination light from the first and second straight tube light sources 12a and 12b and the light reflected by the reflector 13 of the illumination light from the third straight tube light source 12c are projected from the same line. Like that. A rectangular opening 14 is provided on the upper surface of the light source housing 11. The opening 14 is provided to project the direct light from the first to third straight tube light sources 12a, 12b, 12c and the reflected illumination light from the reflector 13 onto the object to be inspected.

In the lighting device having such a configuration, the first
And the direct illumination light projected from the second straight tube light sources 12a and 12b are directly emitted from the opening 14,
A part of the direct illumination light from the second straight tube light sources 12a and 12b is blocked by the reflection plate 13 and is not emitted from the opening 14. On the other hand, the illumination light from the third straight tube light source 12c is made by the reflector 13 and emitted from the opening 14. In other words, the first type which is not blocked by the reflection plate 13
The direct illumination light from the second straight tube light sources 12a and 12b and the reflected illumination light from the third straight tube light source 12c reflected by the reflection plate 13 do not overlap, and
Is emitted from. As a result, illumination unevenness does not occur on the paper, which is an object to be inspected (not shown), from the opening 14, and a uniform amount of illumination light is projected. By performing a binarization process with an electronic computer or the like using the detection signal and comparing it with a reference signal, the defective portion of the paper can be easily detected and determined. In addition, it is possible to eliminate the need to perform analysis determination in consideration of uneven illumination and a difference in light amount.

Further, the first and second straight tube light sources 12
The direct illumination light from the first and second straight tube light sources 12a and 12b and the reflecting plate are aligned by aligning the center lines of the tube axes of the first and second straight tube light sources 12a and 12b with the center line of the reflecting plate 13 in the longitudinal direction. The reflected illumination light of the third straight tube light source 13c reflected at 13 is projected on the object to be inspected as if projected from the same line. For this reason, the light source housing 1
By narrowing the width of the opening 14, the width of the illumination light incident on the inspection object can be reduced to a linear illumination light. As a result, the width of the range detected by the line sensor or the electronic camera is narrowed, and the inspection determination range and the defect position can be set finely, so that more accurate defect determination can be performed.

In the above description, three straight tube fluorescent lamps are used as the straight tube light source. However, three or more straight tube fluorescent lamps may be used depending on the length of the fluorescent lamp in the tube axis direction and the width of the test object. Multiple fluorescent lights are used. In this case, the plurality of fluorescent lamps are arranged and mounted in a checkered manner in the light source housing so that the illumination light is simultaneously projected over the entire width of the object to be inspected, and the upper opening side of the light source housing. There are also provided a plurality of reflectors for reflecting the illumination light of the fluorescent lamp arranged and mounted on the light source. Or
The first and second straight tube light sources 12a and 12b are arranged and mounted inside the bottom surface of the light source housing 11, but are arranged and mounted on the same surface as the side surface on which the third straight tube light source 13c is mounted. Is also possible. In this case, the reflector 1
It is clear that the same effect can be obtained by mounting the third tube 3 between the first and second straight tube light sources 12a and 12b and the third straight tube light source 13c.

Further, although a straight tube fluorescent lamp was used as the straight tube light source, it is apparent that any light source can be used as long as the light emitter is a light source formed in a straight tube shape.

It is also apparent that the pair to be inspected is used as illumination for detecting defects of products manufactured in a film or sheet form other than paper.

[0022]

According to the present invention described above, the illumination light is not uneven due to the difference in the light amount at the boundary of the projection range of the individual illumination light from the plurality of light sources on the inspection object, and the uniform light amount is obtained. The transmitted light of the inspection object can be detected, and the defect detection of the inspection object can be determined by a simple determination analysis process.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional perspective view showing an embodiment of a defect detection illumination device according to the present invention.

FIGS. 2A and 2B are plan views of an illumination device for detecting a defect according to the present invention, wherein FIG. 2A is a top view as viewed from a sectional line AA in FIG.
(B) is a front view as seen from the BB section line in FIG. 1, and (c) is a side view as seen from the CC section line in FIG. 1.

FIG. 3 is a partial cross-sectional perspective view showing a conventional illumination device for defect detection.

FIG. 4 is a partial cross-sectional plan view showing a conventional illumination device for defect detection.

[Explanation of symbols]

11: light source housing, 12: straight tube light source, 13: reflector
14 ... Opening.

Claims (2)

[Claims] 1. A method using transmitted light of a wide and long object to be inspected,
In the defect detection device that detects a defect of the inspection object, a plurality of straight tube light sources for projecting illumination light on the inspection object, the straight tube light sources are arranged and housed in a checkered pattern, and A light source storage case having an opening for projecting the illumination light onto the object to be inspected; and the straight tube light source disposed and stored in the light source storage case, disposed and stored on the opening side of the light source storage case. A reflector that reflects illumination light from the straight tube light source; and projecting illumination light on the device under test by the direct light from the straight tube light source and the reflected light from the reflection plate. An illumination device for detecting defects. 2. The straight tube light source is disposed and housed in the light source housing in a checkerboard pattern having a predetermined interval in the same tube axis direction of the straight tube light source and being parallel to a plurality of tube axis directions. ,
Further, the reflection plate is disposed and mounted at a position on one tube axis that reflects the illumination light from the straight tube light source, and the direct light from the straight tube light source on the other tube axis and the reflected light from the reflection plate 2. The illumination device for detecting a defect according to claim 1, wherein the light is projected onto the inspection object from the same tube axis.