JPH06258252A - Glass surface inspection method and inspection device - Google Patents

Abstract

PURPOSE:To provide a practical inspection method and a device to inspect efficiently and accurately a surface condition of a glass container where fine recesses-projections are applied to the surface being mass-produced. CONSTITUTION:A laser beam is radiated to glass 1 where fine recesses- projections are applied to the surface, and diffused light passing through the glass 1 is captured by an image pickup device 6, and a recessed-projecting condition of the glass surface 1 is judged according to an inclination of intensity distribution of the diffused light image.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inspection method and an inspection apparatus for inspecting a glass surface having fine irregularities on its surface.

[0002]

2. Description of the Related Art Among glass containers filled with alcoholic beverages, especially in some glass bottles, frost is formed on the surface from the aesthetic side.
What has been given a fine asperity called processing is used. Frosting is performed by applying a corrosive liquid to a glass bottle with a smooth surface. The finish condition of the frosting process changes depending on the concentration change of the corrosive liquid when the temperature of the corrosive liquid and the coating time are the same.

If the concentration of the corrosive liquid is proper, the original glass surface is completely corroded and fine irregularities are formed, so that it becomes a good product. When the concentration becomes thin outside the proper range, a part of the original glass surface is not corroded and remains as a fine flat surface portion, and the gloss is different, so that it is regarded as a defective product. In that case, since both the glass bottle and the corrosive liquid are almost homogeneous, the fine plane portions remaining without being corroded are dispersed over the entire surface.

The inspection of the surface condition of the frosted glass bottle for good or defective condition has been conventionally conducted by human eyes, but it is difficult to judge because of sensory factors and it is possible to make a quantitative judgment automatically. Inspection equipment was desired.

[0005]

As a prior art for inspecting fine irregularities on the glass surface, Japanese Patent Laid-Open No. 4-269647 is known.
There is a gazette. This utilizes the fact that there is a difference in the amount of reflected and scattered light from the glass surface between the portion where the unevenness is formed and the portion where the unevenness is not formed by irradiating the glass substrate surface with laser light. In this case, although the presence or absence of fine irregularities on the glass surface can be identified, it is difficult to identify the defective state of the frost processing performed on the glass container as described in the section of the prior art.

An object of the present invention is to provide a practical inspection method and apparatus for efficiently and accurately inspecting the surface condition of glass containers which are produced in large quantities and have fine irregularities. More generally, an object of the present invention is to provide an inspection method for inspecting the surface condition of glass having fine irregularities on the surface.

[0007]

According to the method for inspecting a glass surface of the present invention, laser light is applied to a glass having fine irregularities on the surface, and diffused light transmitted through the glass is captured as a diffused light image by an image pickup device. The uneven state of the glass surface is determined based on the slope of the intensity distribution of the diffused light image.

[0008]

[Function] When the surface of the glass is corroded well without remaining, the laser light transmitted through the glass is largely diffused, and when the diffused light image is captured by the image pickup device, the light intensity of the central portion and the peripheral portion of the diffused light image is obtained. Is small. That is, the light intensity distribution has a mountain shape with a gentle slope. When a part of the glass surface is not corroded and remains as a minute flat surface, when the diffused light image is captured by the image pickup device, the diffusion range of the laser light transmitted through the glass is small, and the central part and the peripheral part of the diffused light are The difference in light intensity is large.
That is, the light intensity distribution has a mountain shape with a steep slope.

With an image pickup device having a plurality of light receiving elements arranged, the difference between the light intensities at two points at a constant distance is obtained, that is, the gradient of the light intensity distribution is obtained. When it exceeds, it is possible to judge the quality of the fine irregularities formed on the glass surface by judging it as a defective product.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings.

In FIG. 1, (A) of the glass surface inspecting apparatus of one embodiment of the present invention is viewed from above, and (B) is B- of (A).
It is explanatory drawing of B cross section. A frosted glass bottle (container) 1 that is filled with liquor or the like is carried by a conveyor 2 to a predetermined inspection position. Whether the glass container 1 has arrived at a predetermined inspection position is determined by, for example, the LED 3 and the light receiving sensor 4
It can be easily detected by the optical position detectors 3 and 4 including. When the optical position detectors 3 and 4 detect that the glass container 1 to be inspected has arrived at a predetermined position, the light projector 5 irradiates the laser light to almost the center of the glass container to be inspected.

The image pickup device 6 composed of a CCD camera is arranged on the opposite side of the inspection position of a predetermined glass container 1 with the conveyor 2 of the light projector 5 interposed therebetween, and an image of the diffused light image of the glass container 1 generated by the irradiation of laser light is imaged. Capture it on the screen. The signal of the diffused light image on the video screen captured by the imaging device 6 is sent to the image processing device (determiner) 7.

Information on the light intensity distribution L of the diffused light image in the X-direction and Y-direction coordinates on the video screen is input to the image processing device 7. The image processing device 7 is an arithmetic processing device equipped with a microcomputer, and arithmetically processes the difference ΔL of the light intensity L at the position between two points ΔX or ΔY apart in the X direction or the Y direction on the video screen. You can That is, the gradient of the light intensity distribution L of the diffused light image can be obtained at each point on the image screen by scanning the image screen to obtain the differential value ΔL / ΔX or ΔL / ΔY.

FIG. 2 is an explanatory diagram of a diffused light image captured on the image screen of the image pickup device. (A) is a case where the finished condition of frosting is good and fine irregularities on the glass surface are formed normally. In this case, the diffused light image is captured as a broad (blurred) wide image as shown in the figure. (C) shows the light intensity distribution L of the diffused light image in this case. The light intensity distribution L is a mountain having a wide spread in the X direction.

(B) is a case where the finish condition of the frosting process is bad and fine irregularities on the glass surface are not sufficiently formed. In this case, the diffuse light image does not spread and becomes a small bright image. (D) shows the light intensity distribution L of the diffused light image in this case. The light intensity distribution L becomes a mountain with a steep slope in the X direction.

Therefore, the diffused light image captured by the image pickup device 6 is obtained by the image processing device 7 to obtain the gradient of the light intensity distribution L, ΔL / ΔX or ΔL / ΔY, and compared with a constant reference value. It is possible to determine the finished state of frosting, that is, whether or not fine irregularities on the glass surface are sufficiently formed.

When the image processing device 7 outputs a signal that the glass surface is not sufficiently uneven, the glass bottle (container) 1 is separated from the conveyor 2 on which non-defective products are lined up. Is transferred to the conveyor as defective.

Needless to say, the gist of the present invention is not limited to the above-mentioned embodiments, but can be widely applied to general inspection of the finish condition of fine irregularities on the glass surface.

[0019]

As described above, according to the present invention,
Since the gradient of the light intensity distribution is obtained from the diffused light image of the transmitted laser light to determine whether it is good or bad, it is possible to quantitatively inspect the fine irregularities formed on the glass surface. That is, since it is not simply judged from the absolute value of the scattered light amount, even if the transmitted light amount changes depending on the color of the glass or the surrounding illuminance changes, it is judged from the relative inclination of the light intensity distribution. The fine irregularities of can be inspected with high accuracy.

The surface of the glass bottle generally has undulations, but in the present invention, it is not affected by undulations because it is judged by transmitted light instead of reflected and scattered light. Further, since the glass bottle is generally circular, when the reflected scattered light is received, it may not be able to be received if the position of the bottle deviates from the specified position, but the transmitted light can be used without any trouble. As described above, according to the present invention, a practical inspection method and apparatus for efficiently and accurately inspecting the surface condition of glass containers in which finely roughened surfaces are mass-produced are realized.

[Brief description of drawings]

FIG. 1 is an explanatory view of an apparatus for inspecting a glass surface according to an embodiment of the present invention, in which (A) is its upper surface and (B) is B- of (A).
The B section is shown.

FIG. 2 is an explanatory diagram of a diffused light image captured by an imaging device.

[Explanation of symbols]

 1 Glass Container (Bottle) 2 Conveyor 3, 4 Optical Position Detector 5 Projector 6 Imaging Device 7 Image Processing Device (Judgment Device)

Claims (3)

[Claims] 1. A glass having a surface with fine irregularities is irradiated with a laser beam, diffused light transmitted through the glass is captured by an image pickup device, and the irregularity of the glass surface is obtained based on the inclination of the intensity distribution of the diffused light image. A method for inspecting a glass surface, which comprises determining a state. 2. A conveyor for carrying a glass container having fine irregularities on its surface to an inspection position, a detector for detecting that the container has arrived at the inspection position, and a projector for irradiating the container with laser light. And an image pickup device that captures a diffused light image that has passed through the container, and a determiner that determines whether the glass container is good or bad based on the inclination of the intensity distribution of the diffused light image by the image pickup device. Glass surface inspection device. 3. The glass surface inspection device according to claim 2, wherein the imaging device is a CCD camera.