JPH05180785A - Method and apparatus for detecting defectiveness of transparent sheet body - Google Patents

Abstract

PURPOSE:To obtain a method and an apparatus for detecting defectiveness of a transparent sheet body which enables identification of various defect parts of the transparent sheet body with a haze value near 0 clearly from the texture thereof. CONSTITUTION:Penetrating light from an upright fluorescence tube 2 arranged at an acute angle 1 in the longitudinal direction to the width Sb of a transparent adhesive sheet body 1 is received with a CCD camera 3. In this case, especially, the penetrating light irradiates a streaky defect part 1a askew along the length Sn of the sheet and a shade is formed at the streaky defect part 1a. The light received with the CCD camera 3 is also skew to the streaky defect part 1a. This constitution enables the photographing of the existence of the streak 1a clear sufficiently.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transparent sheet, for example, a foreign substance contained in an adhesive on a transparent adhesive sheet having a highly transparent resin film as a base material, air bubbles or wrinkles or scratches on the adhesive-coated surface The present invention relates to a detection method and an apparatus therefor for detecting a defective portion such as.

[0002]

2. Description of the Related Art Conventionally, in order to clearly detect such a defective portion as a formation portion, for example, a light source is placed below a transparent adhesive sheet body, and a CCD, for example, a CCD is provided above the transparent adhesive sheet body of the light source. There is a method of monitoring by a detection means such as a camera.

[0003]

It is possible to detect foreign matters and air bubbles in the defective portion, but it is possible to detect the linear stripes formed in the sheet length direction, which are caused by uneven coating of the adhesive. In the case of a defective portion, since the transmitted light is directly received, the detecting means cannot clearly distinguish it from other formation portions.

It is an object of the present invention to provide a defect state detecting method for a transparent sheet body and a detecting apparatus therefor capable of clearly identifying various defects in the transparent sheet body from the formation.

[0005]

In order to achieve the above object, the invention of claim 1 provides an elongated light source from one sheet surface side of a transparent sheet member running in the sheet length direction, the longitudinal direction of which is the transparent sheet. A first acute angle is formed with respect to the sheet width direction of the body, and light from the elongated light source is formed with a second acute angle with respect to the sheet length direction on the other sheet surface side of the transparent sheet body. It is characterized by having done.

According to a second aspect of the present invention, there is provided an elongated light source which is disposed on one sheet surface side of a traveling transparent sheet body and has a first acute angle in a longitudinal direction with respect to a sheet width direction of the sheet body.
It is disposed on the other sheet surface side of the transparent sheet body, receives the transmitted light from the elongated light source through the sheet body, and the light receiving direction is the second with respect to the sheet length direction of the sheet body. And a photoelectric conversion means having an acute angle.

[0007]

The transmitted light from the elongated light source through the transparent sheet is received by the photoelectric conversion means such as a CCD camera. In this case, the transmitted light is reflected especially in the stripe defect along the sheet length direction. Is obliquely irradiated, a shadow is formed on the streak-like defect portion, and the light received by the CCD camera is also oblique to the streak-like defect portion. Can be imaged.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of the detecting device according to the present invention. In FIG. 1, reference numeral 1 denotes a transparent adhesive sheet body that travels in the sheet length direction Sn in a manufacturing line, for example, and a straight fluorescent tube 2 as an elongated light source is provided below the transparent adhesive sheet body 1. There is. Here, the longitudinal direction P of the fluorescent tube 2 is set to an angle θ1 which is an acute angle (for example, 20 °) with respect to the sheet width direction Sb of the sheet body 1.

A CCD camera 3 as photoelectric conversion means is provided above the transparent adhesive sheet body 1, and the light receiving direction Q of the CCD camera 3 is the sheet length direction Sn of the sheet body 1. Acute angle (eg 20 °) θ2
Is set to. Here, the angles θ1 and θ2 are substantially equal acute angles.

As the straight fluorescent tube 2, for example, a daylight-colored high frequency (for example, 30 KHz) fluorescent lamp is used. The CCD camera 3 has a visual field capable of capturing an image of the entire sheet body 1 in the sheet width direction, for example, and the resolution of the visual field is 2048 bits. The CCD camera 3 is provided with a controller (not shown) for inputting an image signal and displaying it on the display.

Further, as shown in FIG.
The intersection angle θ3 formed by the line connecting the CCD camera 3 and the sheet body 1 is set to an acute angle (for example, 30 °).

FIG. 3 shows a constitutional example of the transparent pressure-sensitive adhesive sheet body 1, in which the pressure-sensitive adhesive layer 1B is formed on the transparent resin film substrate 1A having a haze value close to zero. Here, the concave streaks 1a formed on the adhesive layer 1B
Is caused by coating unevenness and the like.

Next, the operation of this embodiment constructed as described above will be explained.

When the transparent adhesive sheet body 1 is running in the sheet length direction, the fluorescent tube 2 is turned on and the irradiation light of the fluorescent tube 2 is applied to the stripe 1a, and the CCD camera 3 within its field of view. The sheet body 1 is scanned in the sheet width direction.

In this case, as shown in FIG. 1, when the line 1a extends in the seat length direction Sn, the irradiation light is emitted to the line 1a at the angle θ1. A predetermined width d behind the streak 1a corresponding to the length of 1a.
To form a shadow that can be imaged.

On the other hand, the light receiving direction of the CCD camera 3 is the angle θ.
Since it is 2, the shadow of the predetermined width d can be clearly distinguished from the formation and can be imaged.

FIG. 4 shows an example of the detection result of the surface state of the transparent adhesive sheet body 1, in which the horizontal axis represents the image pickup position in the sheet width direction and the vertical axis represents the detection signal. It represents a level. In the curve M shown in the figure, the signal amplitude S at the position of arrow A corresponds to the concave streak, and the signal amplitude N at the position of arrow B corresponds to the formation of the sheet 1. The S / N ratio in this case is approximately 2,
Good discrimination is possible.

The signal corresponding to the position of arrow C corresponds to the foreign matter contained in the adhesive.

As described above, according to the structure of this embodiment, it is possible to easily detect various foreign matters contained in the transparent pressure-sensitive adhesive sheet 1 or defective portions such as bubbles as well as streak-like defective portions. In this embodiment, the angle θ2 is set to 20 °, but if the acute angle is within a predetermined range, for example, 25 to 45 °, S /
When the N ratio is 2 or more, streak-like defect portions can be satisfactorily detected.

Although the fluorescent tube 2 is used alone in this embodiment,
Narrow width (eg 4.5m) to improve the clarity of shadows
m) For example, a cardboard mask having slits may be provided on the irradiation side.

Incidentally, the irradiation angle θ2 = θ1 is approximately 90 °.
In other words, when the longitudinal direction P of the fluorescent tube 2 is made to coincide with the sheet width direction Sb of the sheet body 1,
The S / N ratio was close to 1, and it was impossible to distinguish between the streak portion 1a and the formation.

[0022]

As described above, according to the first aspect of the invention, an elongated light source is provided from one sheet surface side of the transparent sheet body running in the sheet length direction, the longitudinal direction of which is the sheet of the transparent sheet body. A first acute angle is formed with respect to the width direction, and the transmitted light of the transparent sheet body has a second acute angle with respect to the sheet length direction on the other sheet surface side of the transparent sheet body. Since it is characterized by performing photoelectric conversion in the direction of forming, in addition to foreign matter and air bubbles contained in the transparent sheet body, it is possible to easily detect streak-like defects due to coating unevenness of the transparent sheet body, Particularly, it is useful when applied to a pressure-sensitive adhesive sheet body using a sheet body having high equal brightness as a base material.

According to the second aspect of the present invention, the transparent sheet is arranged on one sheet surface side of the transparent sheet traveling in the sheet length direction, and the longitudinal direction of the transparent sheet is first with respect to the sheet width direction. And an elongated light source that forms an acute angle, and is disposed on the other sheet surface side of the transparent sheet body, receives light transmitted by the elongated light source through the sheet body, and the light receiving direction is the sheet length of the sheet body. And a photoelectric conversion means forming a second acute angle with respect to the vertical direction. Therefore, the invention of claim 1 can be implemented easily and concretely.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of a detection device according to the present invention.

FIG. 2 is a diagram showing a positional relationship between a fluorescent tube and a CCD camera as seen from a side of a sheet body.

FIG. 3 is a schematic view showing a structure of a transparent adhesive sheet body and a streak defect portion.

FIG. 4 is a graph showing a detection result of a surface state of a transparent sheet body.

[Explanation of symbols]

 1 transparent adhesive sheet body, 2 fluorescent tubes (elongated light source), 3 CCD camera (photoelectric conversion means), Sb sheet width direction, Sn sheet length direction.

Claims (2)

[Claims] 1. An elongated light source is provided from one sheet surface side of a transparent sheet body traveling in a sheet length direction such that a longitudinal direction thereof forms a first acute angle with respect to a sheet width direction of the transparent sheet body. Transparency is characterized in that the transmitted light of the transparent sheet body is photoelectrically converted on the other sheet surface side of the transparent sheet body in a direction in which the light receiving direction forms a second acute angle with the sheet length direction. A method for detecting a defect state of a sheet body. 2. An elongated light source, which is disposed on one sheet surface side of a transparent sheet body traveling in the sheet length direction and has a first acute angle in the longitudinal direction with respect to the sheet width direction of the transparent sheet body, Arranged on the other sheet surface side of the transparent sheet body,
Photoelectric conversion means for receiving transmitted light from the elongated light source through the transparent sheet body and forming a second acute angle with respect to the sheet length direction of the transparent sheet body. A characteristic device for detecting a defect state of a transparent sheet body.