JPH05203588A - Inspecting device of light diffusion body - Google Patents

Abstract

PURPOSE:To obtain an inspection device of a light diffusion body which can properly inspect the light diffusion body which is constituted of materials with different light transmissions in longer shape, has a low transmission as a whole, and has a large amount of defective transmission light. CONSTITUTION:A cigarette filter 1 is carried, one at a time, in radius direction by a drum 2 and a slit 2a which is smaller than the width of the filter 1 and is longer than the filter 1 is formed at the drum 2. An end face 3a of a light guide 3 is laid out in line shape at the inspection position of the filter 1 so that the filter 1 is irradiated through the slit 2a. A line CCD camera 5 is laid out at a light path of transmission light of the filter 1. An image processing device 7 performs binary coding of an image signal by a threshold 21 which is relatively high for detecting an entire length and a space 1c and performs binary coding according to a relatively low threshold 22 to inspect whether each length of two bundles of fibers 1a and 1b is proper or not and whether two bundles of fibers 1a and 1b are arranged alternately or not.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a length of a light diffuser having a low overall transmittance, a length of the light diffuser having a low overall transmittance, an internal change of the light diffuser, an internal defect and a surface. The present invention relates to a light diffuser inspection device for inspecting defects and the like.

[0002]

2. Description of the Related Art Generally, when inspecting a transparent inspection object, a transmission method is used in which light from a light source is applied to the inspection object and the transmitted light is imaged by a camera to detect the change. Further, when inspecting a light-shielding object, a reflection method is used in which light from a light source is applied to an object to be inspected and the reflected light is imaged by a camera. Therefore, when the object to be inspected is a light diffuser such as a translucent resin plate or a cigarette filter, particularly when inspecting the inside of the light diffuser, the transmission method is used.

Conventionally, in an inspection apparatus for inspecting a light diffuser by transporting a light diffuser having a low overall transmittance in the longitudinal direction and made of materials having different light transmittances, the level of transmitted light is increased. A light source with a large amount of light that can detect
Further, since the light diffuser is not always located at the same position in this light source, a light diffuser longer than the length and width is used when inspecting the length and the end of the light diffuser. Generally, an array of point sensors or a line CCD image sensor is used as the image sensor, and the level of transmitted light is relatively low, and the sensitivity is high because it captures a change in the amount of light that has no directivity. A method of using a light receiving element or setting a threshold value when the image pickup signal is binarized to a relatively low level is adopted.

[0004]

Here, as a cigarette filter 1 shown in FIG. 3 as such a light diffuser,
The fiber bundle 1a containing activated carbon and the fiber bundle 1b containing no activated carbon are composed of two components.
It is necessary to inspect whether or not are arranged alternately by using a relatively low threshold value 22. In addition, in order to find a defect or a total length such as a space 1c generated between the fiber bundles 1a and 1b, which has a larger amount of transmitted light than the fiber bundles 1a and 1b, it is necessary to inspect with a high threshold 21.

However, in the above conventional inspection apparatus,
The inspection is performed with one threshold value, and the level of a defect having a larger amount of transmitted light than the fiber bundles 1a and 1b like the space 1c between the fiber bundles 1a and 1b and the relatively transmitted light amount like the fiber bundle 1b. There is a problem that it is not possible to discriminate the level of a material containing a lot of materials.

Therefore, the present invention is capable of optimally inspecting a light diffuser which is composed of materials having different light transmittances in a longitudinal shape, has a low overall transmittance, and has a large amount of light transmitted through a defect. It is an object of the present invention to provide an inspection device of.

[0007]

In order to achieve the above-mentioned object, the present invention provides a first method for measuring a signal imaged by an image pickup means and detecting a defect having a larger amount of transmitted light than a material of a light diffuser. Is binarized by the second threshold for discriminating the material of the light diffuser or detecting a defect having a small amount of transmitted light, and is binarized by the signal binarized by the first threshold. The defect of the light diffuser is detected.

That is, according to the present invention, a light diffuser which is made of materials having different light transmittances in a longitudinal shape and which carries a light diffuser having a low overall transmittance in the width direction to inspect the light diffuser. In the inspection device, in order to support the light diffuser, a slit having a width shorter than the width of the light diffuser and a length longer than the length of the light diffuser, and the light diffuser through the slit. A light source that illuminates, an imaging unit that is disposed on the opposite side of the slit in the optical path of the emitted light of the light source, and captures the transmitted light of the light diffuser, and the signal captured by the image capturing unit Binarized by a first threshold value for detecting a defect having a larger amount of transmitted light than the above material, and the type of the material of the light diffuser or a material having a relatively large amount of transmitted light such as 1b or a surface stain Less transmitted light Recessed inspection apparatus of the light diffuser, characterized in that it comprises an image processing means for binarizing the second threshold value to detect are provided.

[0009]

Since the present invention has the above structure, the level of transmitted light of a defect having a larger amount of transmitted light than that of the material of the light diffuser is binarized by the first threshold value, and the light diffuser defect or the end face of the light diffuser is The entire length is inspected by light reflection. In addition, defects that are binarized by the second threshold value and the type of material of the light diffuser or the amount of transmitted light are small are inspected. Further, the light from the light source is reflected by the end surface of the light diffuser and enters the camera. This light incidence can also be used as the timing to start the inspection with the thresholds 21 and 22.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a first inspection device for a light diffuser according to the present invention.
FIG. 2 is a waveform diagram showing an image pickup signal of a normal filter detected by the inspection device of FIG. 1, and FIG. 3 is a defective filter detected by the inspection device of FIG. It is a waveform diagram which shows an imaging signal.

In FIG. 1, in this inspection apparatus, a cigarette filter 1 is inspected as a light diffuser, and the filter 1 is cut in a subsequent step and attached to the tip of a cigarette, so that the total length is about 100 mm. In addition, as shown in FIG. 2, the inside of the filter 1 is a fiber bundle 1 containing activated carbon.
a and a fiber bundle 1b containing no activated carbon. In a normal state, the two fiber bundles 1a and 1b are alternately arranged in the lengthwise direction and wound with white paper. Such a filter 1 is conveyed by the drum 2 one by one in the width direction, and during the conveyance, the two fiber bundles 1 are conveyed.
a, the length of 1b is correct, the total length is correct, the two fiber bundles 1a, 1b are alternately arranged, whether there is any defect, etc. are also inspected, and in order to eliminate these defects The result is fed back to the production device.

In FIG. 1, the drum 2 has a filter 1
A slit 2a smaller than the width of the filter 1 and longer than the filter 1 is formed in the axial direction, and a light guide 3 is installed at the inspection position of the filter 1 to illuminate the filter 1 through the slit 2a, and the end face 3a. Are arranged in a line. The light guide 3 is made of a plastic fiber, and therefore, the end face 3a can be arranged in a line so as to uniformly illuminate the length direction of the filter 1. The other end face 3 b of the light guide 3 is focused and faces the light source 4. A halogen lamp, for example, is used as the light source 4. Therefore, the light from the light source 4 is guided to the inspection position through the light guide 3, is spread in the length direction of the filter 1 at the end face 3a thereof, and is incident on the filter 1 through the slit 2a.

Then, in order to prevent light from directly entering the camera through the slits 2a at both ends of the filter 1 with respect to the optical path of the transmitted light of the filter 1, the line CCD camera 5 is arranged with respect to the vertical direction of the transport direction of the filter 1. Is placed at an angle,
Therefore, the two fiber bundles are imaged and input to the image processing device 7 in order to inspect whether the lengths are correct, the total lengths are correct, and there is an unfilled portion between the two fiber bundles. It In this embodiment, the line CC
The D camera 5 has a resolution of one pixel of 0.1 mm and a visual field area of 200 mm.

In such a structure, when the normal transmitted light of the filter 1 is imaged, the level of the image pickup signal is the most outside the both ends of the filter 1 due to the reflected light at the both ends of the filter 1, as shown in FIG. It is high, intermediate in the area of the fiber bundle 1b containing no activated carbon, and lowest in the area of the fiber bundle 1a containing activated carbon. Therefore, the total length of the filter 1 can be detected by the threshold value 21 between the outside of both ends of the filter 1 and the level of the fiber bundle 1b containing no activated carbon, and the fiber bundle 1b containing no activated carbon and the fiber bundle 1b containing no activated carbon can be detected. A threshold 22 between the levels of the fiber bundle 1a makes it possible to check whether the respective lengths of the two fiber bundles 1a, 1b are correct and whether the two fiber bundles 1a, 1b are arranged alternately.

On the other hand, as shown in FIG. 3, the fiber bundles 1a, 1
When the transmitted light of the filter 1 in which the space 1c is generated between b is imaged, the amount of transmitted light of the space 1c is steeply projected and becomes substantially the same as the amount of light at both ends of the filter 1, and the threshold 22 alone causes a relatively large amount of transmitted light. It will not be possible to distinguish it from a material part with a large amount of material. Therefore, the image processing device 7 sets the threshold value 21 for detecting both ends of the filter 1 to a detectable value in the space 1c, scans twice, and averages the filter 1 by the average value.
The total length of the space and the space 1c are detected. Then, the threshold value 22 is scanned twice, and it is inspected by the average value whether each length of the two fiber bundles 1a and 1b is correct and whether the two fiber bundles 1a and 1b are alternately arranged.

Therefore, according to the above embodiment, the space 1
It is possible to detect a defect such as c which has a larger amount of transmitted light than the fiber bundles 1a and 1b. Further, according to this embodiment, when detecting the timing when the filter 1 passes through the visual field of the camera 5 from the image signal, the data appearance can be used as the timing of the inspection start by binarizing with the threshold 21. it can. However, if this threshold value 21 is set low, there is a possibility that it will be affected by ambient light or reflected light due to the shape of the drum 2, but the light reflected at both ends of the filter 1
Since the amount of transmitted light is larger than that of a and 1b, both ends of the filter 1 can be reliably detected.

In the above embodiment, the case where the light is incident on the filter 1 through the slit 2a has been described, but in practice, the drum 2 is made of an opaque acrylic plate or the like.
To form a concave portion for supporting the filter 1,
This recess may be formed transparent. Further, although the camera 5 is obliquely arranged with respect to the vertical direction of the transport direction of the filter 1, the end surface 3a of the light guide 3 which is a light source may be obliquely arranged instead. Furthermore, by applying a non-reflective paint or the like to the wall surface of the slit 2a or changing the shape, the amount of light reflected by the wall surface of the slit 2a entering the camera 5 can be reduced. Further, in the case of binarizing the image pickup signal, one scanning signal may be processed by a two-system binarizing circuit instead of scanning a plurality of times.

[0018]

As described above, according to the present invention,
In order to measure the total length and detect a defect in which the amount of transmitted light is larger than that of the material of the light diffuser, it is binarized by the first threshold and binarized by the second threshold to determine the type of the material of the light diffuser or the amount of transmitted light. Since a small number of defects are inspected, it is possible to optimally inspect a light diffuser that is made of materials having different light transmittances and has a longitudinal shape and has a low overall light transmittance.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a first embodiment of an inspection apparatus for a light diffuser according to the present invention.

FIG. 2 is a waveform diagram showing an image pickup signal of a normal filter detected by the inspection device of FIG.

FIG. 3 is a waveform diagram showing an image pickup signal of a defective filter detected by the inspection device of FIG.

[Explanation of symbols]

 1 Cigarette Filter (Light Diffuser) 2a Slit 3 Light Guide 3a Light Guide End Face (Linear Light Source) 4 Light Source 5 CCD Camera 7 Image Processing Device

Front page continued (72) Inventor Tokuyuki Ikeda 3816 Noborito, Tama-ku, Kawasaki City, Kanagawa Prefecture, Mitsubishi Rayon Co., Ltd.

Claims (3)

[Claims] 1. An inspection apparatus for a light diffuser, which is made of materials having different light transmittances and has a longitudinal shape, and which conveys a light diffuser having a low overall transmittance in a width direction to inspect the light diffuser, In order to support the light diffuser, the width is shorter than the width of the light diffuser, the length is longer than the length of the light diffuser, and a light source that illuminates the light diffuser through the slit, An image pickup unit that is arranged on the opposite side of the slit in the optical path of the emitted light of the light source and picks up the transmitted light of the light diffuser; and a signal picked up by the image pickup unit, the amount of transmitted light from the material of the light diffuser. Binarization by a first threshold value for detecting a defect having a large number of defects, and a second threshold value for detecting a defect of a material type of the light diffuser or a small amount of transmitted light.
And an image processing unit that binarizes the image with a threshold value of 1. 2. The image processing means binarizes the signal picked up by the image pickup means by the first threshold value to detect both ends of the light diffuser, thereby inspecting at the second threshold value. The method according to claim 1, wherein
The light diffuser inspection device described. 3. The light diffuser inspection device according to claim 1, wherein a transparent recess is provided so as to support the light diffuser, instead of the slit.