JP2002005630A - Thickness inspector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thickness inspector, in which the thickness of a glass bottle can be measured optically with high accuracy, using laser light. SOLUTION: The thickness inspector comprises means 1 for irradiating a glass bottle 20 with stripe laser light having a constant width, a lens 2 receiving the laser light reflected on the inner and outer surfaces of the glass bottle 20, an image pickup means 3 for capturing the reflected light passed through the light receiving lens 2 as an image screen, and a unit 4 for operating the average thickness at a part of constant width irradiated with laser light from the image screen.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thickness inspection apparatus capable of optically accurately measuring the thickness of a glass bottle using laser light.

[0002]

2. Description of the Related Art Conventionally, as a method of inspecting the thickness of a glass bottle or the like, as shown in, for example, Japanese Patent Application Laid-Open No. 5-180609, the capacitance is measured by measuring the capacitance in a certain area to calculate the thickness. A method and a method of calculating a wall thickness by measuring reflected light from an inner surface and an outer surface of a glass bottle using halogen light are known. Recently, the measurement accuracy has been improved by using laser light instead of the halogen light (for example, see Japanese Patent No. 3025268 and Japanese Patent Application Laid-Open No. 6-201336).

[0003] However, in the method of measuring the capacitance, if the surface of the glass bottle is provided with a dielectric hot coating, there is a problem that the thickness cannot be measured accurately due to the influence. On the other hand, although the method of measuring the reflected light is not affected by such a phenomenon, glass bottles have unique irregularities such as seams and joints of the mold, scratches on the surface, and skin irregularities. For this reason, in the conventional method in which the halogen light or the laser light is radiated to only one point in a point manner, there is a problem that the joints, the flaws and the like are erroneously recognized as the wall thickness defect.

[0004]

SUMMARY OF THE INVENTION The present invention solves the conventional problems as described above, and is not affected by the dielectric hot coating even if it is applied. The present invention has been completed for the purpose of providing a wall thickness inspection apparatus capable of measuring the wall thickness of a glass bottle with high accuracy without generating an erroneous signal and at a high speed.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a thickness inspection apparatus according to the present invention comprises a means for irradiating a band-shaped laser beam having a fixed width toward a glass bottle, A light receiving lens for receiving the reflected light from the inner surface and the outer surface of the resulting glass bottle, an imaging means for capturing the reflected light passing through the light receiving lens as an image screen, and a constant width irradiated with laser light from the image screen An arithmetic unit for calculating an average thickness of a portion is provided.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. The drawing shows a case where the thickness of the glass bottle 20 sequentially conveyed into the inspection area is inspected. In the drawing, 1 is a means for irradiating the glass bottle 20 with laser light, and 2 is this laser light. A light receiving lens for receiving light reflected from the inner surface and the outer surface of the glass bottle 20 caused by the light, 3 an imaging means such as a two-dimensional CCD camera for capturing the reflected light passing through the light receiving lens 2 as an image screen, 4 An arithmetic unit for calculating the thickness based on a signal from the video screen.

As shown in FIG. 3, the laser light emitted from the means 1 for irradiating the laser light has a band shape having a constant width of about 5 mm (thickness of about 0.1 mm), for example. By using such a belt-like laser beam, it is possible to accurately calculate the wall thickness without any influence even if there are irregularities such as joints and scratches. Note that a laser beam having a wavelength in the visible light region, such as a semiconductor laser, is used as such a laser beam.

Further, the means 1 for irradiating the laser light comprises:
As shown in FIG. 2, it is composed of a semiconductor laser oscillator 1a, a collimator lens 1b, and a cylindrical lens 1c, and is configured to accurately generate a band-shaped laser beam having a constant width.

As shown in FIG. 4, the light receiving lens 2 receives the reflected light from the inner surface and the outer surface of the glass bottle 20 generated by the laser light, and sends the reflected light to the imaging means 3 comprising a two-dimensional CCD camera. Accurately enter without reducing the amount of light. In this two-dimensional CCD camera, light reflected from the inner surface and the outer surface is two-dimensionally received and distributed as a surface displacement and a back surface displacement, respectively.

The means 1 for irradiating the laser beam, the light receiving lens 2 and the image pickup means 3 constitute a sensor head 5 as
It is united into individual units and has a compact design. A plurality of the sensor heads 5 are installed, and the thickness of the glass bottle 20 can be inspected over the entire circumference.

Next, the signal output from the sensor head 5 is input to the arithmetic unit 4, where the thickness is converted by the calculation of the CPU to measure the thickness. In the present invention, a band-like laser beam is used. Therefore, the thickness corresponding to the width of the laser beam is regarded as an averaged value. As a result, even if there are irregularities such as seams or scratches on the surface of the glass bottle 20, the effect is very small, and only a thin portion can be reliably detected.

After the wall thickness is measured in this way, as shown in FIG. 1, data is sent to the wall thickness determination unit 10, where it is compared with a preset threshold value to determine whether it is good or bad. A determination is made. Further, in the defect determination, a discharge signal is issued via the sequencer 11, and after the discharge signal is shift-registered, the defective part is discharged in the discharge unit of the inspection machine. Further, based on the signal from the sequencer 11, the counter 12 counts various kinds of data of the bottle having a poor thickness. In addition, the thickness determination unit 1
The control value of 0 and the like can be arbitrarily set according to an instruction from the control panel 13.

As described above, according to the present invention, the means 1 for irradiating the glass bottle 20 with a belt-like laser beam having a constant width is provided.
A light receiving lens 2 for receiving light reflected from the inner surface and the outer surface of the glass bottle (20) generated by the laser light;
The imaging device 3 includes an imaging unit 3 that captures reflected light passing through the light receiving lens 2 as an image screen and an arithmetic unit 4 that calculates an average thickness of a fixed width portion irradiated with laser light from the image screen. The measurement of the wall thickness is different from the conventional measurement in which only one point is measured in a point manner, and the average value of a certain width is calculated. Therefore, even if there are irregularities such as seams or scratches on the surface, it is not affected by the irregularity, and it is possible to reliably detect only a case where the thickness is thin over a certain width and the thickness is truly defective.

When an experiment was conducted on the wall thickness inspection accuracy of a glass bottle using the apparatus of the present invention, the inspection accuracy could be increased to 0.1 mm. Conventionally, in the case of an accuracy of 0.1 mm, irregularities such as joints and scratches on the surface were also mistakenly recognized as poor wall thickness, and the excellent effect of the present invention was confirmed. Although the above description has been given of the case of the thickness inspection of a glass bottle, it is needless to say that the present invention can be similarly applied to the thickness inspection of a preform for a PET bottle and the thickness inspection of various glass products or plastic products. It is.

[0015]

As is apparent from the above description, the present invention is not affected by the dielectric hot coating even if it is applied, and generates an erroneous signal even if there are seams or scratches. The thickness of the glass bottle can be measured with high accuracy and at high speed without any problem.
Therefore, the present invention has an extremely large contribution to industrial development as a thickness inspection apparatus that has eliminated the conventional problems.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an entire system showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a main part of the present invention.

FIG. 3 is an explanatory diagram showing a state in which a belt-shaped laser beam is irradiated.

FIG. 4 is an explanatory view showing a principle of measuring a wall thickness.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 A means for irradiating a belt-like laser beam 1a Semiconductor laser transmitter 1b Collimator lens 1c Cylindrical lens 2 Light receiving lens 3 Imaging means 4 Arithmetic unit 5 Sensor head 20 Glass bottle

Claims (2)

[Claims] 1. A means (1) for irradiating a band-shaped laser beam having a certain width toward a glass bottle (20), and reflected light from the inner surface and the outer surface of the glass bottle (20) generated by the laser beam. A light receiving lens (2) for receiving light, and an imaging means (3) for capturing reflected light passing through the light receiving lens (2) as an image screen;
A wall thickness inspection apparatus comprising: an arithmetic unit (4) for calculating an average wall thickness of a fixed width portion irradiated with laser light from the video screen. 2. The apparatus according to claim 1, wherein the means for irradiating the laser beam comprises a semiconductor laser oscillator, a collimator lens, and a cylindrical lens. .