KR100377116B1 - Lighting instrument using light emitting diode and curved surface reflecting mirror and automatized defect inspection system comprising the same lighting instrument - Google Patents

Abstract

In the lighting apparatus used in the automated defect inspection apparatus, a curved reflector capable of reflecting light emitted from the light emitting diode toward the inspected object is provided, and the light reflected by the curved reflector is irradiated to the inspected object. This avoids square illumination, preventing shadows from occurring and achieving uniform illumination.

Description

Lighting device using light emitting diode and curved surface reflecting mirror and automatized defect inspection system comprising the same lighting instrument

The present invention relates to a lighting apparatus using a light emitting diode and a curved reflector and an automated defect inspection apparatus including the same. Specifically, the present invention relates to an illumination defect and an automated defect inspection apparatus including the same. It is about.

In the production process of all products, defect inspection process is performed to evaluate the completeness of the finished product after the manufacturing process. In this case, the defects may be referred to collectively as all the factors that hinder the characteristics of the product, there may be a defect of various sizes ranging from very small invisible to the naked eye can be seen with the naked eye.

Inspection of the appearance defect of a relatively large object is usually performed by randomly extracting a sample and inspecting the product with the naked eye, and a small object may also be inspected by a microscope or the like. However, in this case, since it is impossible to inspect all the produced products and subjective inspection by visual observation of the worker, objective product inspection is difficult.

In order to solve this problem, an inspection system that automates the inspection process is used, which is a standard that is pre-inputted through image analysis software to obtain an image of a product obtained through a CCD (charge-coupled device) camera. By comparing and analyzing the images and making scientific decisions, the objective is to automate objective inspection and quality control.

Such automated inspection equipment can be broadly classified into optical systems, image analysis systems, and machine control systems. The optical system illuminates the area to be measured and acquires the reflected image and transmits it to the image analysis system.The image analysis system converts the analog signal of the transmitted image into a digital signal and compares and analyzes it with the standard image inputted in advance. In this case, the defects are classified by grade and the result is output. The machine control system directly classifies defective products by type and grade according to the image analysis results.

In general, in semiconductor processes that require precise patterning techniques, fine scratches and dusts can cause fatal operating errors, requiring precise defect inspection equipment, and the appearance of relatively large objects such as glass bottles and can lids. To prevent errors, defects can be checked with relatively simple inspection equipment.

Equipment that is used for close inspection requires position correction precision down to micron units and typically analyzes local area images. Therefore, when inspection of a relatively large area is required, the entire area to be measured is analyzed by scanning, so the inspection time becomes longer in proportion to the inspection area. In addition, since all images acquired by scanning must be compared and analyzed, the time required for image analysis is much longer depending on the inspection area. For this reason, the inspection of fine defects in products such as semiconductor patterns is very precise but limited to inspection of a few randomly extracted samples.

Simple inspection equipment is used to check the appearance defects of relatively large products such as glass bottles, can lids, and goggles. Since the equipment acquires images through a simple optical system, it is difficult to precisely measure due to interference caused by diffuse reflection. It is mainly used for the inspection of large defects such as damage or breakage. In such a case, there is an advantage that full inspection is possible, but there is a problem that defect inspection of a small product in millimeters is very difficult due to problems such as interference of the optical system or shadow generation due to blind spots.

Illumination devices used in such prior art automated defect inspection apparatus are shown in FIGS. 1A and 1B. FIG. 1A shows the inspection device from the side, and FIG. 1B shows the lighting device of FIG. 1A from the bottom. The lighting device of FIG. 1A is shown along the line II ′ of the lighting device of FIG. 1B.

As illustrated in FIGS. 1A and 1B, an image capturing unit 120 and an illumination device 110 are used to obtain an image of a target object 130 to be inspected for defects. The lighting device 110 is formed in a donut shape having a hole in the center thereof so that the image capturing unit 120 can capture an image of the target object 130, and includes a plurality of light emitting diodes (LEDs) 111. do. Light emitted from the LED 111 irradiates the target object 130, and the imaging unit 120 obtains an image of the target object 130 using the light reflected by the target object 130.

However, when imaging using a conventional lighting device as shown in Figures 1a and 1b, due to the opening 112 in the center of the lighting device 110 provided for the imaging unit 120 to the target object 130 It is difficult to obtain uniform illumination, and light emitted from the periphery of the opening 112 is incident at an inclined angle with respect to the target object 130, thereby causing a shadow phenomenon. Due to such a shadow phenomenon, it is very difficult to inspect a defect of an object having a certain thickness or more, and particularly, as shown in FIG. 1, this problem is more prominent in the case of the object 130 having an opening.

The present invention was conceived to solve such a problem, and an object of the present invention is to provide a lighting device that can eliminate the shadow phenomenon caused by blind spots.

It is another object of the present invention to provide an illumination device and an automated defect inspection system that enable defect inspection of a target object having a certain thickness or more.

1A and 1B show a lighting device according to the prior art, in which FIG. 1A is a side view of the lighting device and FIG. 1B is a bottom view of the lighting device.

Figure 2 is a schematic diagram showing the overall structure of the automated defect inspection apparatus according to an embodiment of the present invention.

3A-4C show various embodiments of a lighting device according to the invention.

5A and 5B show an actual example of an image obtained for an object to be inspected by using a lighting device according to the related art and a lighting device according to the present invention, respectively.

The illumination device of the present invention for solving such a problem comprises a first surface having a first opening and a second surface having a second opening facing the first surface and at least partially overlapping the first opening. A light emitting diode provided on a support, a plurality of light emitting diodes provided on an inner surface of the support, a third opening attached to the first surface of the support and at least partially overlapping the first and second openings; And a curved reflecting mirror capable of reflecting in the direction of the second opening of the second surface.

In addition, the display apparatus may further include a backlight unit disposed in a direction opposite to the first surface with respect to the second surface, and the backlight unit may include a plurality of light emitting diodes.

On the other hand, another illumination device according to the present invention, an illumination device that can irradiate light to the target object, an imaging device that can receive the light reflected from the target object to obtain an image of the target object, the target obtained from the imaging device An illumination device used in an automated defect inspection device that includes an image analysis device capable of comparing and analyzing an image of an object with a standard image. The lighting device is arranged to reflect a light source and light from the light source in a direction of a target object. The device is characterized in that it comprises a curved reflector having an opening formed to receive light reflected from the object.

In addition, the automated defect inspection apparatus according to the present invention is arranged to reflect the light source, the light from the light source in the direction of the target object, the curved reflector having an opening in the center, the light reflected from the target object through the opening And an image analyzing means capable of receiving and acquiring an image of the target object, and image analyzing means capable of comparing and analyzing the image of the target object acquired by the imaging means with a standard image.

Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

2 is a schematic view showing the overall configuration of an automated defect inspection apparatus according to the present invention.

The automated defect inspection apparatus 200 according to the present invention may be largely divided into a measurement optical system 230 and an image analysis system 240. The measuring optical system 230 includes an image capturing unit 232 and an illuminating unit 231 including a CCD camera and the like. The measuring optical system 230 acquires a reflected image by illuminating an area to be measured and transmits the reflected image to the image analyzing system 240. That is, the measurement target object 220 is sequentially moved through the belt 210 to pass through a predetermined position below the measurement optical system 230, at which time the image of the target object 220 is obtained by the measurement optical system 230 The image analyzer 240 includes an image processing processor 241, a memory device 242, a display unit 243, and the like, which converts an analog signal of an image transmitted from the measurement optical system 230 into a digital signal and inputs the digital signal in advance. Compare and analyze with the standard image, and classify the defect by type and grade and display the result through the display. In addition, although not shown in the drawings, the results may be used to directly classify defective items by type and grade.

3a to 3c show examples of illumination used in the automated inspection device according to the invention.

3A to 3C, the lighting apparatus of the present invention includes a plurality of light emitting diodes 312, 322, 332 and supports 317, 327, which are attached to the supports 317, 327, 337 and the inside of the support. It is attached to the upper portion of 337, the openings 314, 324, 334 are formed in the center, and consists of curved reflectors 313, 323, 333 reflecting light from the light emitting diodes 312, 322, 332. The supports 317, 327, and 337 are formed to include at least two sides facing each other (FIGS. 3A: 317_1, 317_2, and FIG. 3B: 327_1, 327_2, and 3C: 337_1, 337_2). Here, the surface (FIG. 3A: 317_1, FIG. 3B: 327_1, FIG. 3C: 337_1) to which the curved reflector 313, 323, 333 is attached is called a 1st surface, and the 1st surface 317_1, 327_1, 337_1) will be referred to as a second surface (FIGS. 3A: 317_2, 3B: 327_2, and 3C: 337_2). The first side 317_1, 327_1, 337_1 and the second side 317_2, 327_2, 337_2 each have a first opening (Fig. 3A: 317_3, Fig. 3B: 327_3, Fig. 3C: 337_3) and a second opening (Fig. 3A: 317_4, FIG. 3B: 327_4, and FIG. 3C: 337_4, wherein the first openings 317_3, 327_3, and 337_3 and the second openings 317_4, 327_4, and 337_4 overlap some or all of the first openings. And the image capturing units 315, 325, and 335 through the second openings 317_3, 327_3, 337_3, 317_4, 327_4, and 337_4 to image the target objects 316, 326, and 336. As described, the curved reflectors 313, 323, and 333 attached to the first surfaces 317_1, 327_1, and 337_1 of the supports 317, 327, and 337 also have openings 314, 324, and 334 in the center. Formed. The openings 314, 324, and 334 formed in the curved reflectors 313, 323, and 333 are referred to as third openings to distinguish them from the first and second openings 317_3, 327_3, 337_3, 317_4, 327_4, and 337_4. Shall be. For imaging, the third openings 314, 324, and 334 should also be formed to overlap some or all of the first and second openings 317_3, 327_3, 337_3, 317_4, 327_4, and 337_4. Light emitted from each of the light emitting diodes 312, 322, and 332 of the first and second light emitting diodes 331 is reflected by the curved reflectors 313, 323, and 333, through the second openings 317_4, 327_4, and 337_4. 336, and the imaging units 315, 325, and 335 installed above the third openings 314, 324, and 334 of the curved reflectors 313, 323, and 333 are the target objects 316, 326, and 336. The light reflected from the image is used to obtain an image of the object 316, 326, or 336.

Since the light directed to the target object is not directly irradiated from the light emitting diode to the target object, but is reflected toward the target object by the curved reflector, uniform illumination can be obtained despite the presence of the aperture. The angle of inclination of the light can be adjusted by appropriately adjusting parameters such as and curvature, the distance between the light emitting diode and the curved reflector, the direction in which the light emitting diode is placed, and the distance between the curved reflector and the target object. In the case of having a shadow effect can be prevented from appearing, even if there is a groove or an opening in the target object can obtain an accurate image.

The backlight unit may be further installed to more accurately obtain an image of the object. 4A to 4C show an embodiment of the lighting apparatus of the present invention provided with such a backlight unit.

As shown in FIGS. 4A to 4C, the backlight units 411, 421, and 431 are installed on opposite sides of the illumination device and the imaging unit when viewed based on the object. The backlight units 411, 421, and 431 include supports 413, 423, and 433 and a plurality of light emitting diodes 412, 422, and 432. The backlight units 411, 421, and 431 may also be formed in a structure including a light emitting diode and a curved reflector similarly to the main lighting devices 311, 321, and 331, but the backlight unit does not require an opening for the imaging unit. As with ordinary lighting devices, light emitted from the light emitting diodes may be irradiated directly to the object.

5A and 5B show actual examples of images of a target object obtained by using a lighting device of the prior art and a lighting device according to the present invention.

As a result of comparing the images obtained for the annular target object, as shown in FIG. 5A, the image obtained by the measurement optical system using the illumination device of the prior art has a shadow on the edge of the target object and the center of the annular shape, resulting in darkening. On the other hand, the image obtained by the measuring optical system using the illumination device of the present invention, as shown in Figure 5b, almost no shadow phenomenon can be obtained similar to the appearance of the actual target object.

Although the present invention has been described in detail with reference to preferred embodiments, this embodiment has been presented for the purpose of understanding the present invention, and the scope of the present invention is not limited to this embodiment. Those skilled in the art to which the technology of the present invention belongs will appreciate that various modifications are possible without departing from the scope of the technical idea of the present invention.

In the lighting apparatus according to the present invention, by irradiating light to a target object using a curved reflector, a much more uniform illumination can be obtained than in the prior art lighting, thereby preventing shadows from being generated even with a thick object. You can get a clear image of the target object.

Therefore, the automated defect inspection system including such an illumination device has a thickness of a certain degree or more, and satisfactory defect inspection can be performed even for a product having a groove or an opening.

Claims (10)

A support comprising a first face having a first opening and a second face facing the first face and having a second opening at least partially overlapping the first opening, A plurality of light emitting diodes provided on the inner surface of the support, A third opening attached to the first surface of the support, the third opening overlapping at least a portion of the first opening and the second opening, wherein light from the plurality of light emitting diodes is emitted from the second opening of the second surface; Lighting device comprising a curved reflector capable of reflecting in the direction. The method of claim 1, And a backlight unit positioned in an opposite direction to the first surface with respect to the second surface. The method of claim 2, The backlight unit includes a plurality of light emitting diodes. An illumination device that can irradiate light onto a target object, an imaging device that can receive the light reflected from the target object, to obtain an image of the target object, and an image of the target object obtained by the imaging device to a standard image. In the lighting device used in the automated defect inspection device including an image analysis device capable of comparative analysis, With a light source, And a curved reflector arranged to reflect light from the light source in a direction of the target object, the curved reflector having an opening formed to receive the light reflected from the target object. Device. The method of claim 4, wherein The light source includes a plurality of light emitting diodes. The method of claim 4, wherein And a backlight unit disposed in a direction opposite to the curved reflector with respect to the target object to irradiate light to the target object. Light Source, A curved reflector disposed to reflect light from the light source in a direction of a target object and having an opening in a center thereof; Imaging means capable of receiving light reflected from the target object through the opening to obtain an image of the target object; And an image analyzing means capable of comparing and analyzing the image of the target object acquired by the imaging means with a standard image. The method of claim 7, wherein And the light source includes a plurality of light emitting diodes. The method of claim 7, wherein And a backlight unit disposed in a direction opposite to the curved reflector with respect to the target object to irradiate light to the target object. The method of claim 9, The backlight unit comprises a plurality of light-emitting diodes.