JPH0743317A - Apparatus for inspecting defects on sheet-like object - Google Patents

Abstract

PURPOSE:To provide an apparatus for inspecting defects on a sheet-like object that can accurately detect any defects existing on the sheet-like object. CONSTITUTION:The apparatus is provided with an illumination part 10 for applying a linear illumination light 11 onto a sheet-like object 201, a camera part 20 which receives the reflecting lights generated through illuminating from the part 10 and converts them into electrical signals, and a processing part 30 which calculates their intensities based on the electrical signals sent from the part 20 and detects the defects on the object 201. In such an apparatus, an illumination light 11 of the part 10 is inclined to the feeding direction of the object 201 and is applied thereon.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet-like defect inspection apparatus for inspecting a defect existing in a sheet-like substance to be inspected.

[0002]

2. Description of the Related Art When a sheet-like material is produced, various defects may occur on the surface of the sheet-like material. The defect inspection apparatus for sheet-like objects inspects these defects occurring in the sheet-like objects.

There are the following types of defect inspection devices for sheet materials. The sheet-like material sent by the roll is irradiated with light. The reflected light from this illumination is received and converted into an electric signal, and the density of the sheet-like material is detected from this electric signal. If there is a defect in the sheet-like material, the reflected light changes and the density becomes non-uniform. Defects are detected from this change in density.

In this way, the defect inspection apparatus for a sheet-like object inspects whether or not a defect exists in the sheet-like object. A defect inspection apparatus for this sheet-like material is disclosed in JP-A-58-16.
No. 0852. In this sheet defect inspection apparatus, as shown in FIG. 10, a roll 101 feeds a sheet 201. Then, the lamp 102 emits light from a direction perpendicular to the feeding direction 301 of the sheet 201 and a direction inclined with respect to the sheet 201. The camera 103 converts the reflected light into an electric signal, and the processing circuit 104 checks the change in the density of the reflected light from the electric signal.

[0005]

However, the above-described sheet defect inspection apparatus, for example, the apparatus shown in FIG. 10, has the following problems.

In this defect inspection apparatus, the lamp 102 irradiates the sheet-like object 201, which is an object to be inspected, with light, and the processing circuit 104 detects a change in reflected light. The defects existing in the sheet 201 include a stripe defect 202 parallel to the longitudinal direction of the sheet 201 as shown in FIG. When the illumination light 102A is incident on the stripe-shaped defect 202 as shown in the AA cross-sectional view of FIG. 11B, the reflected light hardly changes at the stripe-shaped defect 202. For this reason, the density becomes almost uniform, and the stripe-shaped defect 202 is not detected, or the sheet-like material 201 is not detected.
A change in the density occurs at the edge portion 203 of the
2 may be detected as a dot defect. As a result,
Defect inspection accuracy is reduced.

Further, when the sheet-like material 201 is fed by using the roll 101 or the like, since the roll 101 is rotated by a motor or the like, vibration may occur and the vibration may cause the sheet-like material 201 to vertically vibrate. When such vibration occurs, the reflected light is disturbed, and the defect inspection accuracy deteriorates.

An object of the present invention is to provide a defect inspection apparatus for a sheet-like material, which eliminates such defects and can improve the detection accuracy of defects existing in the sheet-like material.

[0009]

SUMMARY OF THE INVENTION In order to achieve the object, a first aspect of the present invention receives an illuminating section for irradiating a sheet-like object with linear illuminating light and a reflected light generated by illuminating the illuminating section. In a sheet-like object defect inspection apparatus including a camera unit for converting the electric signal from the camera unit and a processing unit for detecting a defect in the sheet-like member by checking the density from the electric signal from the camera unit, in the sheet-like object feeding direction, On the other hand, the illumination light of the illumination unit was inclined and irradiated.

According to a second aspect of the present invention, an illuminating section for irradiating a sheet-like object with linear illuminating light, a camera section for receiving reflected light generated by illumination of the illuminating section and converting it into an electric signal, and a camera section In the sheet-like object defect inspection apparatus including a processing unit that detects the density of the sheet-like object by checking the density from the electric signal of the sheet-like object, the incident portion of the sheet-like object on which the illumination light from the illumination unit enters From the side opposite to the incident direction, there is a pressing portion that applies tension along the incident portion.

[0011]

According to the first aspect of the invention, the illuminating section irradiates the linear illumination light with an inclination and irradiates the sheet-shaped object at a predetermined incident angle. Thereby, even if there are streak-shaped defects substantially parallel to the longitudinal direction of the sheet-like material, the illumination light is obliquely incident on the streak-shaped defects. As a result, the reflected light changes at the streak-like defect, and the streak-like defect substantially parallel to the longitudinal direction of the sheet-like material can be detected.

According to the second aspect of the present invention, the pressing portion presses the portion of the sheet-shaped article on which the illumination light is incident, so that the sheet-shaped article is tensioned. As a result, it is possible to prevent the vibration of the sheet-like material due to the rollers that feed the sheet-like material.

[0013]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is a schematic diagram showing an embodiment of the present invention. The defect inspection apparatus for this sheet-like object is provided with an illumination unit 1.
0, a camera unit 20, a processing unit 30, an output unit 40, and a pressing unit 50.

Illumination unit 10 of the defect inspection apparatus for sheet-like material
Irradiates the sheet 201 with the linear illumination light 11. At this time, the illumination section 10 irradiates the sheet 201 with the illumination light 11 at an incident angle θ1 as shown in FIG. The incident angle θ1 is usually in the range of 30 degrees to 60 degrees,
In this embodiment, it is set to 45 degrees. At the same time, as shown in FIG. 3, the illumination section 10 is arranged so as to be inclined by an angle θ2 with respect to the feeding direction 301 of the sheet 201. In this embodiment, it is set to 45 degrees. Lighting unit 1
Examples of 0 include a fluorescent lamp.

The camera section 20 has a line C as a light receiving element.
A CD (charge coupled device) is provided. Line CCD is CC
The sheet-like material 201 is an element in which Ds are arranged in a line.
The linear reflected light from is received and an electric signal corresponding to the linear reflected light is generated. This electric signal is a black and white video signal of reflected light.

The processing unit 30 includes an A / D (analog / digital) converter 31, an image memory 32, and a central controller 33.
With.

The A / D converter 31 of the processing section 30 converts the black and white video signal from the camera section 20 into 8 bits and 25 bits, for example.
Quantize to 6 gradations. As a result, the black and white video signal is converted into a digital signal.

The image memory 32 stores the digitized monochrome video signal from the A / D converter 31.

The central controller 33 has a CPU (Centra) inside.
l Processing Unit) and ROM, and the CPU follows a control procedure stored in advance in the ROM (not shown).
(Not shown) performs the following processing. Central controller 3
As shown in FIG. 4, 3 integrates the density value of each pixel in the feed direction 301 by a predetermined number based on the monochrome video signal stored in the image memory 32 (step S1). And
The average value Ai of each pixel is calculated from the integrated value obtained in step S1.
(For example, 1 ≦ i ≦ 2048) is calculated (step S
2) The average value Ai is a one-dimensional signal perpendicular to the feed direction 301. The central controller 33 compares the preset threshold Th with the average value Ai (step S
3). If the comparison result is the average value Ai> threshold value Th, it is determined that there is no streak-like defect, and a signal indicating normality is output to the output unit 40 (step S4). If the average value Ai ≦ threshold value Th, it is determined that there are streak defects and a signal indicating abnormality is output (step S5).

The central controller 33 determines the presence or absence of streak-like defects by such control.

The output unit 40 displays the inspection state of the sheet 201 by the signal from the processing unit 30 indicating normality or abnormality. At this time, if the inspection result is abnormal, an alarm may be issued.

The pressing portion 50 is formed from the portion on the opposite side of the sheet-like material 201 on which the illumination light 11 is incident, from the sheet-like material 20.
1 is pressed to give tension to the sheet 201. An example of the pressing portion 50 is shown in FIGS. 6 is a diagram of FIG. 5 viewed from the direction of arrow 302.

This pressing portion 50 is a base portion 51 provided on the opposite side of the portion of the sheet 201 on which the illumination light 11 is incident.
Equipped with. Ball portions 52, 52 are attached to the base portion 51 in parallel with each other between the base portion 51 and the sheet-like material 201. The ball portions 52, 52 are provided so as to be inclined with respect to the feeding direction 301 of the sheet 201. The opposite side of the portion between the ball portion 52 and the ball portion 52 is the portion on which the illumination light 11 is incident. Each ball portion 52 includes a holder 53. The holder 53 is directly attached to the base 51. Each holder 53 is provided with a groove portion 53A, and a plurality of balls 54 are rotatably placed in the groove portion 53A. At this time, each ball 54 presses the sheet 201 in the direction 303 perpendicular to the sheet 201. As a result, the sheet-like material 201 is
It will be in a state to bend to 03.

The pressing portion 50 is thus provided with the sheet-like material 20.
Press 1.

Further, as the pressing portion 50, there are the following ones. This pressing portion is shown in FIGS. In addition, in FIG.
FIG. 8 is a diagram of FIG. 7 viewed from a direction of an arrow 304. The pressing unit includes a base 61, like the pressing unit 50. Roll portions 62, 62 are attached to the base portion 61 between the base portion 61 and the sheet 201 in parallel with each other. The rolls 62, 62 are provided so as to be inclined with respect to the feeding direction 301 of the sheet 201. The opposite side of the portion between the roll portions 62 and 62 is the portion where the illumination light 11 enters. Each roll unit 62 includes a plurality of rolls 63. These rolls 63 are attached to the base 61 in a stepwise manner. Moreover, each roll 63 is rotatably held by a support 64. This support base 64 is the base 61
Is attached to. Each roll 63 has a sheet-like material 2
The sheet 201 is pressed in the direction 303 perpendicular to 01.

You may use such a pressing part.

Next, the operation of this embodiment will be described.

When the sheet-like object 201 has a stripe-like defect parallel to the longitudinal direction of the sheet-like object 201, and the stripe-like defect reaches the pressing portion 50, the illuminating section 10 is illuminated.
Illuminates the stripe-shaped defect with the illumination light 11. At this time,
The illumination unit 10 irradiates the stripe-shaped defect with the illumination light 11 at an incident angle θ1 (FIG. 2) and at an angle θ2 (FIG. 3) with respect to the feed direction 301. As a result, as shown in FIG. 9, a shadow 1 is formed on the stripe-shaped defect 202 of the sheet-like material 201 at the edge portion 202A of the stripe-shaped defect 202.

At the same time, the portion irradiated with the illumination light 11 is pressed by the pressing portion 50. Therefore, even if the sheet 201 vibrates by a feed roller (not shown) or the like, the pressing portion 50 is pressed.
Sheet-like object 20 between the ball portion 52 and the ball portion 52 of the
1 does not vibrate.

The camera section 20 receives reflected light that includes the shadow 1 and is not disturbed, and sends a monochrome video signal to the processing section 30. The processing unit 30 converts the black-and-white video signal into the A / D converter 3
The image memory 32 stores the digital signal by converting it into a digital signal at 1. The central controller 33 inspects the presence or absence of streak defects from the digitized black and white video signal stored in the image memory 32. Then, a signal indicating normality or abnormality, which is the inspection result, is output to the output unit 40. The output unit 40 displays the inspection state, and if there is an abnormality in the inspection result, issues an alarm or the like to notify the abnormality.

As described above, according to this embodiment, even if there are streak-shaped defects 202 parallel to the longitudinal direction of the sheet 201, since the illumination unit 10 is inclined, the streak-shaped defects 202 are shadowed. 1 can be reliably generated. Further, according to this embodiment, even if the sheet-like material 201 vibrates, the pressing portion 50 presses the sheet-like material 201, so that the vibration of the sheet-like material 201 at the portion of the pressing portion 50 can be prevented. As a result, this embodiment can improve the inspection accuracy of defects in the sheet 201.

In this embodiment, the length of the streak-like defect to be selected can be changed by adjusting the number of pixels to be integrated in step S1 under the control of the central controller 33. Further, by changing the setting range of the threshold Th used in step S3, it is possible to change the detection level of the streak-like defect.

Further, under the control of the central controller 33, the threshold value Th may not be set in advance, and a value obtained by adding an offset to the average value of the one-dimensional signal may be used as the threshold value.

[0035]

As described above, according to the first aspect of the invention, the reflected light changes at the streak-like defect.
It is possible to detect streak-like defects that are substantially parallel to the longitudinal direction of the sheet-shaped material. As a result, this line-shaped defect is surely detected, so that the inspection accuracy of the sheet-like material can be improved.

According to the second aspect of the invention, the sheet-like material does not vibrate due to the rollers or the like for feeding the sheet-like material. As a result, the disturbance of the reflected light is prevented, so that the inspection accuracy of the sheet-like material can be improved.

[Brief description of drawings]

FIG. 1 is a schematic view showing an embodiment of the present invention.

FIG. 2 is a diagram showing how the illumination unit illuminates.

FIG. 3 is a diagram showing how the illumination unit illuminates.

FIG. 4 is a flowchart showing a process of a central controller.

FIG. 5 is a diagram showing a pressing portion.

FIG. 6 is a diagram showing a pressing portion.

FIG. 7 is a diagram showing another example of a pressing unit.

FIG. 8 is a diagram showing another example of a pressing unit.

FIG. 9 is a diagram for explaining a defect inspection.

FIG. 10 is a diagram showing a conventional defect inspection apparatus for a sheet-shaped material.

FIG. 11 is a diagram for explaining a defect inspection.

[Explanation of symbols]

 10 Illumination unit 11 Illumination light 20 Camera unit 30 Processing unit 201 Sheet-like material

Claims (4)

[Claims] 1. A lighting unit that irradiates a sheet-shaped object with linear illumination light, a camera unit that receives reflected light generated by the illumination of the lighting unit and converts it into an electric signal, and electricity from the camera unit. In a defect inspection device for a sheet-like object, comprising: a processing unit for detecting a defect from the signal to detect a defect in the sheet-like object, and irradiating the illumination light of the illumination unit with respect to a feeding direction of the sheet-like object. A defect inspection device for a sheet-like object, characterized in that 2. A lighting unit for irradiating a sheet-shaped object with linear illumination light, a camera unit for receiving reflected light generated by illumination of the lighting unit and converting it into an electric signal, and electricity from the camera unit. In a sheet-like material defect inspection apparatus including a processing unit that detects a density of a sheet-like material by detecting a density from a signal, an incident portion of the sheet-like material on which the illumination light from the illumination unit is incident is illuminated light. 2. A defect inspection apparatus for a sheet-like object, comprising: a pressing portion that applies tension along the incident portion from a side opposite to the incident direction. 3. The pressing portion has two rows of ball portions, each of which is provided so as to sandwich the incident portion of the sheet-shaped material, and has a plurality of balls. Defect inspection system for sheet materials. 4. The pressing section has two rows of roll sections each provided with a plurality of rolls, which are arranged so as to sandwich the incident portion of the sheet-like material. Defect inspection system for sheet materials.