JP3241785B2 - Light diffuser inspection equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light-diffusing body which is made of a material having a different light transmittance and has a long length, and a 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 In general, when inspecting a transparent object to be inspected, a transmission method is used in which light from a light source irradiates the object to be inspected, and the transmitted light is imaged by a camera to detect the change. When inspecting a light-shielding object, a reflection method is used in which light from a light source irradiates 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, the transmission method is used particularly when inspecting the inside of the light diffuser.

[0003] Conventionally, an inspection apparatus which is formed in a longitudinal shape with materials having different light transmittances, and which conveys a light diffuser having a low overall transmittance in the width direction to inspect the light diffuser has a level of transmitted light. A light source with a large amount of light that can detect
In addition, since the light diffuser is not always located at the same position, a light source longer than the length and width of the light diffuser is used when inspecting the length and the end of the light diffuser. As an image sensor, generally, an array of point sensors arranged in an array or a line CCD image sensor is used. The level of transmitted light is relatively low, and the sensitivity is high to capture a change in the amount of light without directivity. A method of using a light receiving element or setting a threshold value for binarizing an imaging signal to a relatively low level is adopted.

[0004]

Here, as such a light diffuser, as in a cigarette filter 1 shown in FIG.
It consists of two components, a fiber bundle 1a containing activated carbon and a fiber bundle 1b not containing activated carbon.
Are required to be checked based on the relatively low threshold value 22 to determine whether or not are alternately arranged. Further, in order to obtain a defect having a larger amount of transmitted light than the fiber bundles 1a and 1b, such as a space 1c generated between the fiber bundles 1a and 1b, and a total length, the inspection must be performed with a high threshold value 21.

However, in the above-mentioned conventional inspection apparatus,
Inspection is performed with one threshold, and the level of a defect such as the space 1c between the fiber bundles 1a and 1b, which has a larger amount of transmitted light than the fiber bundles 1a and 1b, and the relatively transmitted light amount such as the fiber bundle 1b There is a problem that the level of a material having a large amount cannot be identified.

Accordingly, the present invention provides a light diffuser which can be optimally inspected for a light diffuser which is formed of materials having different light transmittances in a longitudinal shape and has a low overall transmittance and a large amount of transmitted light of defects. It is an object of the present invention to provide an inspection device.

[0007]

According to the present invention, in order to achieve the above object, a light diffuser is provided by a light source in a longitudinal direction thereof.
Evenly illuminated and arranged so that light from the light source does not directly enter
The signal picked up by the picked-up imaging means is binarized by a first threshold value for measuring the total length and detecting a defect having a larger amount of transmitted light than the material of the light diffuser, and identifying or transmitting the material of the light diffuser. Binarizing with a second threshold for detecting a defect with a small amount of light, detecting a defect of the light diffuser with a signal binarized with the first threshold ,
The total length of the light diffuser is detected by the first threshold, and the second
Material parts with different light transmittance according to the threshold are arranged alternately
To check if they are.

That is, according to the present invention, in a light diffuser inspection apparatus for inspecting a light diffuser formed of a material portion having a different light transmittance in a longitudinal shape and having a low overall transmittance,
A light source that uniformly illuminates the light diffuser in its length direction, regardless of the presence or absence of the light diffuser, is disposed relatively to the light source so that light from the light source does not directly enter, The transmitted light of the light diffuser and the reflection at both end faces of the light diffuser
Imaging means for imaging the emitted light, and binarizing a signal obtained from the image taken by the imaging means with a first threshold for detecting a defect having a larger amount of transmitted light than the material of the light diffuser; An image processing means for binarizing the light diffuser with a second threshold for detecting a defect of a material type or a small amount of transmitted light ;
Means for detecting the total length of the light diffuser using the fact that the reflected light is larger than the first threshold value, and the material portions having different light transmittances according to the second threshold value are alternately arranged. and means for checking whether the arranged in the inspection apparatus of the light diffuser, characterized in that it has, is 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 the material of the light diffuser is binarized by the first threshold value, and the defect at the light diffuser defect or the end face of the light diffuser is determined. The entire length is inspected by light reflection. Further, a defect which is binarized by the second threshold value and has a small type of material of the light diffuser or a small amount of transmitted light is inspected. Further, light from the light source is reflected on the end face of the light diffuser and enters the camera. This light incidence can also be used as the timing to start the inspection based on 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 embodiment of the light diffuser inspection apparatus according to the present invention.
FIG. 2 is a waveform diagram showing an image signal of a normal filter detected by the inspection device of FIG. 1, and FIG. 3 is a diagram of a defective filter detected by the inspection device of FIG. FIG. 4 is a waveform chart showing an image pickup signal.

In FIG. 1, in this inspection apparatus, a filter 1 of cigarette is inspected as a light diffuser, and this filter 1 is cut in a later step and attached to the tip of a cigarette, so that the total length is about 100 mm. 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 length direction, and are wound with white paper. Such a filter 1 is conveyed one by one in the width direction by a drum 2, and the two fiber bundles 1 are conveyed during this conveyance.
a, 1b are correct, the total length is correct, the two fiber bundles 1a, 1b are alternately arranged or there is no defect, and the inspection is performed to remove these defects. The result is fed back to the production equipment.

In FIG. 1, a 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 provided at an inspection position of the filter 1 to illuminate the filter 1 through the slit 2a. Are line-shaped. The light guide 3 is made of a plastic fiber. Therefore, the light guide 3 can be linearly arranged on the end face 3a so as to uniformly illuminate the filter 1 in the longitudinal direction. Further, the other end face 3 b of the light guide 3 is focused and faces the light source 4. Note that, for example, a halogen lamp is used as the light source 4. Therefore, the light from the light source 4 is guided to the inspection position via the light guide 3, is spread in the longitudinal direction of the filter 1 at the end face 3a, and enters the filter 1 via the slit 2a.

The line CCD camera 5 moves the filter 1 in a direction perpendicular to the transport direction of the filter 1 so that light does not directly enter the camera from the slits 2a at both ends of the filter 1 with respect to the optical path of the transmitted light of the filter 1. Placed at an angle,
Therefore, an image is taken to check whether the lengths of the two fiber bundles are correct, the total length is correct, whether there is a portion where nothing is filled between the two fiber bundles, and the like, and the image is input to the image processing device 7. You. In this embodiment, the line CC
The D camera 5 has a resolution of one pixel of 0.1 mm and a viewing area of 200 mm.

In such a configuration, when the light transmitted through the normal filter 1 is imaged, the level of the imaged signal is the highest at the outside of both ends of the filter 1 due to the reflected light at both ends of the filter 1 as shown in FIG. It is high and is intermediate in the region of the fiber bundle 1b containing no activated carbon, and lowest in the region 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 outer ends 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 activated carbon-containing fiber bundle 1b can be detected. The threshold value 22 between the levels of the fiber bundles 1a makes it possible to check whether the 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.
When the transmitted light of the filter 1 in which the space 1c is generated between the points b and b is imaged, the transmitted light amount of the space 1c protrudes sharply and becomes almost the same as the light amount at both ends of the filter 1. Cannot be distinguished from a material part having a large amount. Therefore, the image processing apparatus 7 sets the threshold value 21 for detecting both ends of the filter 1 to a detectable value of the space 1c, scans twice, and calculates the average value of the filter 1 based on the average value.
And the space 1c are detected. Then, scanning is performed twice using the threshold value 22 to check whether the respective lengths of the two fiber bundles 1a and 1b are correct and whether the two fiber bundles 1a and 1b are alternately arranged based on the average value.

Therefore, according to the above embodiment, the space 1
It is possible to detect a defect as shown in FIG. Further, according to this embodiment, when detecting the timing at which the filter 1 passes through the field of view of the camera 5 from the image signal, the data appearance may be used as the test start timing by binarizing with the threshold 21. it can. However, if the threshold value 21 is set to a low value, there is a possibility that the light reflected by the disturbance light or the shape of the drum 2 may be affected.
Since the transmitted light amounts are larger than the transmitted light amounts a and b, both ends of the filter 1 can be reliably detected.

In the above embodiment, the case where light enters the filter 1 through the slit 2a has been described. However, in practice, the drum 2 is made of an opaque acrylic plate or the like.
To form a recess for supporting the filter 1,
This recess may be formed transparent. Further, although the camera 5 is disposed obliquely with respect to the vertical direction of the transport direction of the filter 1, the end face 3a of the light guide 3, which is a light source, may be disposed obliquely instead. Further, the amount of light reflected by the wall surface of the slit 2a and incident on the camera 5 can be reduced by applying a non-reflective paint or the like to the wall surface of the slit 2a or changing the shape. Further, when binarizing the imaging signal, instead of scanning a plurality of times, one scan signal may be processed by two systems of binarization circuits.

[0018]

As described above, according to the present invention,
In order to measure the total length and to detect a defect having a larger amount of transmitted light than the material of the light diffuser, it is binarized by a first threshold and binarized by a 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 formed of materials having different light transmittances and having a long overall transmittance. Also, the first threshold
The entire length is detected by detecting both ends of the light diffuser, and the second threshold is detected.
Two types of light diffusers with different light transmittances are alternately arranged depending on the value.
You can check if they are queued.

[Brief description of the drawings]

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

FIG. 2 is a waveform diagram showing an image signal of a normal filter detected by the inspection device of FIG. 1;

FIG. 3 is a waveform diagram showing an image pickup signal of a defective filter detected by the inspection device of FIG. 1;

[Explanation of symbols]

 Reference Signs List 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

Continuation of the front page (72) Inventor Tokuyuki Ikeda 3816 Noboru Noto, Tama-ku, Kawasaki-shi, Kanagawa Prefecture (72) Inventor Yukio Shibuya 2-3-19-1 Kyobashi, Chuo-ku, Tokyo Mitsubishi Rayon Co., Ltd. 56) References JP-A-2-128112 (JP, A) JP-A-58-210554 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01N 21/88-21/894 G01B 21/02

Claims (4)

(57) [Claims] 1. A light diffuser inspection apparatus for inspecting a light diffuser formed of a material portion having a different light transmittance and having a low overall transmittance, wherein said light diffuser has a length A light source that uniformly illuminates in the direction, regardless of the presence or absence of the light diffuser, disposed relatively to the light source so that light from the light source does not directly enter;
Imaging means for imaging the transmitted light of the light diffuser and the reflected light at both end faces of the light diffuser; and a signal obtained from an image imaged by the imaging means, the material of the light diffuser An image which is binarized by a first threshold for detecting a defect having a large amount of transmitted light and binarized by a second threshold for detecting a type of a material of the light diffuser or a defect having a small amount of transmitted light. Processing means , the reflected light at each end face of the light diffuser being greater than the first threshold
Means for detecting the total length of the light diffuser by using the following, and means for checking whether material portions having different light transmittances are alternately arranged according to the second threshold value, Light diffuser inspection device. 2. An inspection apparatus configured to be able to convey a light diffuser in a width direction thereof, wherein said image processing means converts a signal imaged by said imaging means into two in accordance with said first threshold value. The light diffuser inspection apparatus according to claim 1, wherein the inspection is started by detecting both ends of the light diffuser by converting into a value. 3. A slit having a width shorter than the width of the light diffuser and a length longer than the length of the light diffuser to support the light diffuser, wherein the light source is provided through the slit. The inspection device according to claim 1, which illuminates the light diffuser. 4. The light diffuser inspection apparatus according to claim 3, wherein a transparent concave portion is provided so as to support the light diffuser, instead of the slit.