KR20030096780A - Apparatus for inspecting defect of glass and control method thereof - Google Patents

Abstract

PURPOSE: An apparatus and a method for inspecting defects of glass are provided to inspect defects in various kinds of glasses by detecting the defects of glasses after a grinding process has been finished. CONSTITUTION: A defect inspecting apparatus for glass includes an inspection table, on which a panel(3) to be inspected is placed. A light source is provided so as to radiate light towards the panel(3). A blocking mirror blocks unnecessary components of light. A shutter(60) is provided so as to shut off light generated from a lamp as necessary. A grid mask(20) is provided in order to selectively transmit light. A color filter(50) is provided in order to improve sensitivity of a pattern formed at a rear surface of the panel(3). A projection lens(30) is positioned between the grid mask(20) and the panel(3). A mirror(40) is positioned between the projection lens(30) and the panel(3).

Description

Glass defect inspection device and its method {APPARATUS FOR INSPECTING DEFECT OF GLASS AND CONTROL METHOD THEREOF}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a defect inspection apparatus and method for glass, and more particularly, to a defect inspection apparatus and method for inspecting a defect formed during a molding process of glass.

If there is a glass defect such as a dissimilar glass layer inside a transparent or semi-transparent flat plate or soft curvature produced by various manufacturing methods, if the glass defect exceeds the size of the defect specified in the prescribed standard or specification, etc. It is generally judged to be a defective product and discarded. Such glass includes not only cathode ray tube glass used in TVs (Television), computer monitors, etc. but also window glass of buildings and automobiles, but will be described below with respect to cathode ray tube glass for convenience of description.

Cathode ray tubes generally have a panel on which an image is projected and a funnel-shaped funnel having an electron gun coupled to the back of the panel. The molding of such a panel is performed by pressing a glass raw material which is heated and melted in a glass melting furnace and provided in the form of a gob by a press molding apparatus.

In this way, the compression molded panel is a predetermined stud pin is fused by a stud pin fusion device for supporting the shadow mask, and then slowly cooled to a predetermined temperature condition through a slow cooling furnace, and then for each control point of the panel It is directed to the gauging process to measure the dimensions. After measuring the Ferri Peri and the peripheral dimensions from the gauge process, the panel finishes the first external inspection and finishes the polishing process toward the polishing process for polishing the end and effective surfaces by a predetermined conveying means. It is released as a product to companies that manufacture the final product.

Among products manufactured through such a series of manufacturing processes, a panel having defects therein, that is, a defective product, may be manufactured for some reason, but there is a problem in that it is not easy to find such a defective product. The reason is that before the polishing process, the curvature of the surface itself is so severe that diffuse reflection and birefringence on the surface make it difficult to detect the glass defect of the panel. Visual inspection of glass defects is possible, but since the other side is a rough sanding surface, it is difficult to find glass defects due to refractive index differences due to diffuse reflection here. Therefore, there is a problem that it is very difficult to determine the correct glass defect by visual inspection which depends on the naked eye of the worker.

In addition, in the case of visual inspection in accordance with the naked eye of the prior art, it is difficult to find the glass defects formed inside the panel because the accurate inspection is not performed immediately after the polishing process, the panel with glass defects is the final product As a result, the cost of defective products, such as post-shipment recovery expenses, is increased, and the quality of the shipped products is statistically degraded. There is a problem that the feed-back is delayed and consequently the correction is delayed, resulting in a large process loss.

Accordingly, it is an object of the present invention to provide a defect inspection apparatus and method for glass that can detect defects in glass immediately after the polishing step in view of such a conventional problem.

1 is a perspective view schematically showing a defect inspection apparatus of glass according to the present invention;

2 is a side view of FIG. 1;

3 is a view illustrating a light transmission band and a light blocking band of a grid mask;

4 is a diagram for illustrating the principle of detecting a defect in glass according to the present invention.

* Explanation of symbols for the main parts of the drawings

10: light source 20: film member

30: projection lens 40: mirror

50: color filter 60: shutter

According to the present invention, there is provided a defect inspection apparatus for inspecting a defect formed in glass, comprising: a light source for irradiating light toward the glass from one side of the glass; And a lattice pattern formed between the glass and the light source, the lattice pattern being formed in a detection area by the light irradiated from the light source toward the glass, and the lattice pattern causing defects and interferences formed in the glass. Is achieved by a glass defect inspection apparatus comprising a film member in which a light shielding band and a light transmitting band of a predetermined width are alternately arranged to produce a).

Here, it may be configured to further include an inspection unit for detecting the defect of the glass by capturing the Moire Fringe, Projection Lens (Projection Lens) to adjust the area irradiated with light passing through the film member It may be provided between the film member and the glass. In addition, it may be configured to further include at least one mirror for reflecting the light passing through the projection lens at a predetermined angle, the color filter to improve the sensitivity of the Moire Fringe between the light source and the film member It can also be configured to include (Color Filter).

On the other hand, according to another field of the present invention, the object is a defect inspection method for inspecting a defect formed in the glass, comprising the steps of: arranging the glass to be inspected; Irradiating light so that the light blocking band and the light transmitting band having a predetermined width pass through the film member formed alternately; And detecting a defect formed in the glass by inspecting a moire fringe formed by the lattice pattern of the film member formed in the detection area causing interference with the defect formed in the glass. It is also achieved by a defect inspection method.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 is a perspective view schematically illustrating a defect inspection apparatus of glass, and FIG. 2 is a side view of FIG. 1. As shown in these figures, the defect inspection apparatus for glass according to the present invention includes a detection table (not shown) on which the panel 3 to be inspected is placed and a predetermined side toward the panel 3 from one side of the panel 3. A light source 10 for irradiating light of the light source, a blocking mirror 11 for blocking components of an unnecessary wavelength region of the light source 10, a shutter 60 for blocking light of a lamp if necessary, and To improve the sensitivity of the pattern generated in the grid mask 20, which is a film member in which fine light transmission bands and light blocking bands are alternately formed, and the detection area that is the rear surface of the panel 3; A color filter 50, a projection lens 30 provided in front of the grid mask 20 between the grid mask 20 and the panel 3, the projection lens 30 and the panel ( 3) disposed between the mirrors to reflect the light emitted from the light source 10.

The light source 10 which irradiates predetermined light to the panel 3 to be inspected is provided in the light source housing 13. In general, the light source 10 uses a halogen lamp having a maximum intensity of 150 watts (WATT), but if an LED (Light Emitting Diode) is available, an LED (Light Emitting Diode) may be used. Although the light source housing 13 is installed under the detection stand and has a cylindrical shape having a rectangular cross section, the shape of the light source housing 13 is not limited to a cylindrical shape having a rectangular cross section, but a cylindrical shape having a rectangular cross section. You can also do In addition, a blocking mirror 11 is installed on the front surface of the light source 10 to block components in unnecessary wavelength regions of the lamp 10, which is a light source, so that it is not harmful to the eyes of the operator who detects the glass defect 5 of the panel 3. Do not

In addition, the light irradiated from the light source 10 passes through the color filter 50 provided on the front surface of the light source housing 13. The color filter 50 whose material is quartz glass is provided in order to improve the sensitivity of the pattern created in the detection area | region of the panel 3, and to reduce the fatigue of an operator's eyes.

In addition, the shutter 60 provided on the front of the color filter 50 is for blocking the light of the lamp, and the power is applied to the lamp 10 so that the lamp 10 is not inspected even when the lamp 10 is turned on. If you want to cut off the light with the shutter 60 can be stopped for a while, when you want to check again, open the shutter 60 so that the light of the lamp 10 is irradiated to the panel (3). This is to prevent frequent on / off when the lamp 10 is turned off by turning off the power of the lamp 10 when it is not necessary to use it for a long time.

FIG. 3 is a diagram illustrating a light transmission band and a light blocking band of a grid mask 20. As shown therein, the grid mask 20 alternately arranges a light transmission band and a light blocking band. And the width of the light transmission band D and the width of the light blocking band C are approximately 2 μm to 4 μm, depending on the enlargement ratio of the projection lens 30. Can lose.

The width of the light transmission band D and the width of the light blocking band C are about 30 μm to 70 μm and about 80 μm to 150 μm when they appear in a lattice pattern on the back surface of the panel 3. The material of the grid mask 20 is quartz glass and the light blocking band C is chrome plated. Meanwhile, the grid mask 20 and the light blocking band C may be formed of other materials.

The projection lens 30 is a light irradiation area so that light passing through the grid mask 20 can form a lattice pattern in a required area in a detection area that is the rear surface of the panel 3 of the panel 3. It serves to enlarge or reduce.

The light passing through the projection lens 30 is reflected by the mirror 40 provided in front of the projection lens 30 and irradiated toward the panel 3 placed on the detection stand. The mirror 40 is installed obliquely in front of the projection lens 30 and reflects the light passing through the projection lens 30 to reflect the grid pattern generated by the grid mask 20 on the back of the panel 3 placed on the detection table. Create Light may be irradiated to the panel 3 placed on the detection stand directly through the projection lens 30 without installing the mirror 40, but in this case, the projection lens 30 when the panel 3 falls or foreign matter falls. In order to prevent the lens from being damaged, the mirror 40 may be used to adjust the distance to which light is irradiated. On the other hand, the surface of the mirror 40 is coated with aluminum.

According to such a structure, the defect inspection method of glass is demonstrated as follows.

As described above, the molding of the panel is performed by pressing the glass raw material which is heated and melted in the glass melting furnace and provided in the form of a gob by a press molding apparatus, and the compression molded panel is prescribed by a stud pin welding device for supporting the shadow mask. After the stud pins are fused, they are slowly cooled to a predetermined temperature condition through a slow cooling furnace, followed by a gauging process for measuring the dimensions of each control point of the panel, and after the visual inspection by the first visual inspection, The polishing operation is carried out toward the polishing process for polishing the end face and the effective face by predetermined transfer means.

At this time, with the cord inspection apparatus according to the present invention, the panel 3 performs a full inspection to extract and inspect all products after the polishing process.

The inspection method according to the present invention is based on a moire phenomenon, and when light passes through the grid mask 20 having isotropy and regularity, a lattice pattern having regularity is generated, which passes through the grid mask 20. The light is refracted by the glass defects 5 of the panel 3, causing interference with the lattice pattern. Thus, the wavy pattern in which the lattice pattern is distorted with the naked eye is generated. By detecting the defect, fine defects or fine steps can be detected. It is based on the principles that exist.

In the method of performing the inspection, first, when the panel 3 to be inspected is placed on the detection stand while the power is applied, the switch is operated by the load of the panel 3 to block the lamp 10 which is the light source. The shutter 60 is opened to irradiate light from the lamp 10, and the predetermined light irradiated from the lamp 10 is a blocking mirror 11, a color filter 50, and a light blocking band and light transmission having a predetermined width. The band passes through the grid mask 20, which is an alternately formed film member. In addition, the light passing through the grid mask 20 passes through the projection lens 30 to irradiate all of the grid pattern formed by the grid mask 20 to the detection area that is the rear surface of the panel 3. The irradiation area is adjusted.

Then, the light passing through the projection lens 30 is reflected by the mirror 40 inclined to the front of the projection lens 30 to be directed to the back of the panel 3 placed on the detection table and the detection is the back of the panel 3 A grid pattern having isotropy and regularity is formed in the region. When the grid pattern formed as described above has a glass defect 5 inside the panel 3, as shown in FIG. 4, the lattice pattern causes interference with the glass defect 5 to generate a moire fringe. That is, the line generated by the light passing through the defect formed in the panel 3 is compared with the other line generated by passing through the inside of the panel 3 without defect and is adjacent to the adjacent line. Partial spacing and width difference of (A and A 'or B region) are shown. If this partial gap and width difference is found, it can be seen that there is a defect inside the panel 3. In the case of A and A 'areas, this is the case where there is a heterogeneous glass layer among the glass defects, and in the case of the B area, it corresponds to stones or bubbles in the glass defects.

As described above, the glass including the light source 10 for irradiating light toward the panel 3 and the grid mask 20 for forming a lattice pattern in the detection area by the light irradiated from the light source 10. By the defect inspection apparatus, it is possible to detect the glass defects 5 which can be formed in the panel 3 immediately after the polishing process and at the pre-shipment stage. Accordingly, it is possible to block the increase of the cost due to the defective product and to quickly identify and correct the process causing the glass defect 5 by improving the quality and feedback.

In the above-described embodiment, the detection of the glass defects 5 of the panel 3 by irradiating the wavy pattern formed on the panel 3 with the naked eye of the operator without separately configuring the inspection unit has been described above. An image pickup camera positioned above 3) and a detection section for detecting glass defects 5 by image processing a signal for a wave pattern picked up by the image pickup camera may be provided.

In the above-described embodiment, the glass defect 5 of the cathode ray tube panel 3 is detected by irradiating a wave pattern formed on the cathode ray tube panel 3, but the defect inspection apparatus for glass according to the present invention has been described. Of course, not only the cathode ray tube panel 3 but also various kinds of glass can be used to detect glass defects.

As described above, according to the present invention, there is provided an apparatus for inspecting defects of glass and a method for detecting glass defects immediately after a polishing process.

Claims (6)

In the defect inspection apparatus of glass for inspecting defects formed in the glass, A light source for irradiating light toward the glass from one side of the glass; And It is provided between the glass and the light source, the lattice pattern is formed in the detection area by the light irradiated toward the glass from the light source, the lattice pattern causes a defect and interference phenomenon formed in the glass (Moire Fringe) And a film member in which a light blocking band and a light transmitting band having a predetermined width are alternately arranged to produce a light defect. The method of claim 1, And an inspection unit configured to detect the defect of the glass by capturing the Moire Fringe. The method of claim 1, And a projection lens provided between the film member and the glass to adjust a region in which light passing through the film member is irradiated. The method of claim 3, And at least one mirror for reflecting light passing through the projection lens at a predetermined angle. The method according to any one of claims 1 to 4, And a color filter provided between the light source and the film member to improve sensitivity of the moire fringe. In a defect inspection method of glass for inspecting a defect formed in the glass, Arranging the glass to be inspected; Irradiating light so that the light blocking band and the light transmitting band having a predetermined width pass through the film member formed alternately; And Detecting a defect formed in the glass by inspecting the Moire Fringe caused by the lattice pattern of the film member formed in the detection region caused interference with the defect formed in the glass method of inspection.