KR20070121820A - Glass inspection systems and methods for using same - Google Patents

Abstract

Several different inspection systems and methods are described herein that identify defects (e.g., inclusions, onclusions, scratches, stains, blisters, cords or other imperfections associated with surface discontinuities or material non-homogeneities) on or within a glass sheet.

Description

GLASS INSPECTION SYSTEMS AND METHODS FOR USING SAME}

This application enjoys the benefit of priority from US Application No. 60 / 669.171, filed April 6, 2005, entitled “Glass Inspection System and Glass Inspection Method Using the Same,” which is incorporated herein by reference. .

The present invention generally relates to inspection systems and methods used to identify defects on the surface and inside of glass.

Manufacturers of glass sheets always have defects (eg, internal and external inclusions, onclusions), scratches, blemishes, blisters that exist inside or on the surface of a glass sheet (eg, a liquid crystal display (LCD) glass substrate). Efforts are being made to design new and improved glass inspection systems capable of identifying cords or other inhomogeneities or materials associated with surface discontinuities. Several new and improved inspection systems are the subject of the present invention.

The present invention includes several other embodiments of inspection systems and methods for identifying defects (eg, internal and external inclusions, scratches, nicks, blisters, codes) on the surface and interior of a glass sheet. In one embodiment, the inspection system includes an illuminator, a lens and a line-scan sensor. The dimmer emits a light beam, and the lens emits a parallel light beam passing through a portion of the glass sheet after receiving the light beam. The line-scan sensor can then receive the parallel light beam passing through the glass sheet and focus on the incomplete element in the glass sheet without having to place another lens between the line-scan sensor and the glass sheet.

The present invention may be more fully understood by referring to the following detailed description in conjunction with the accompanying drawings.

1A to 1F are six diagrams related to the first embodiment of the inspection system according to the present invention.

2A to 2C are three diagrams related to the second embodiment of the inspection system according to the present invention.

3A to 3E are five diagrams related to the third embodiment of the inspection system according to the present invention.

4A to 4C are three diagrams related to the fourth embodiment of the inspection system according to the present invention.

5A to 5C are three diagrams related to the fifth embodiment of the inspection system according to the present invention.

6a to 6d are four diagrams related to the sixth embodiment of the inspection system according to the invention.

7a to 7d are four diagrams related to the seventh embodiment of the inspection system according to the invention.

1A and 1F, six diagrams related to the inspection system 100 according to the first embodiment of the present invention are shown. FIG. 1A shows a cylindrical lens 106 that travels through the glass sheet 110 and reflects all rays in the laser line 104 with a parallel light beam 108 received by the line-scan sensor 112. An inspection system 100 that includes a laser diode 102 that produces a laser line 104 passing therethrough. An important characteristic of the inspection system 100 is that it can focus on the incomplete element of the glass sheet 110 without having to place another lens between the line-scan sensor 112 and the glass sheet 110. In this embodiment, the distance between the cylindrical lens 106 and the sensor 112 is about 4 ". The beam width of the parallel light beam 108 is 3 to 5". And, the glass sheet 110 is changeable by ± 1 inch at the position between the cylindrical lens 106 and the sensor 112.

The inspection system 100 is a significant improvement over conventional inspection systems that require a lens that must be precisely placed between the glass sheet 110 and the sensor 112 to focus on defects in the glass sheet 110. For example, conventional inspection systems inspect incomplete elements in orders of 1 to 200 microns that require a depth of field less than 10 ^-4 meters (couple of millimeters). In contrast, the inspection system 100 of the present invention has the same depth of field in the range of inches. This is because the light beam traveling directly from the lens 102 to the small sensor element of the sensor 112 through the lens 106 collimated to the inspection system 100 (the sole purpose of which is to move the rays parallel to each other). 104). And, if a small obstruction such as a defect disturbs the optical path, this disturbance is captured by the sensor 112. This disturbance can occur at any point in the optical path between the laser 102 and the sensor 112. As such, the inspection system 100 can detect and measure incomplete elements using sensors that are very tolerant of the object distance as compared to conventional inspection systems.

1B-1E show different incomplete image of different glass sheets 110 scanned by inspection system 100. To obtain each image, sensor 112 outputs a quantized signal and inputs it to a computer that can be analyzed with an image processing algorithm that can be displayed in graphical form. By observing the generated image, the height of the signal generated by the incomplete element can be known. Incomplete elements are small inclusions and in this series of experiments they are small particulates of platinum, zirconium, stainless steel or other contaminants. To produce this image, the laser 102 creates a highly coherent light line 104 such that a Fresnel effect can appear. The Fresnel effect sends light energy around the dark incomplete element and forms a peak that can be higher than the light 104 generated by the laser 102. As such, the Fresnel effect generates a very high signal for the noise ratio so that small incomplete elements can be easily detected.

1F shows the change in the size of defects in the scanned glass sheet 110 at locations 1 ", 1.5", 2.0 ", 2.5" and 3 "from the sensor 112. The size of the defects varies but other measurements The change is small compared to the device and the change is measurable and predictable The graph also indicates that the farther the defect is from the sensor 112, the larger the magnitude of the defect calculated by the predictable amount. Indicates that the inverse of the size change is a correction factor that can be used when calculating the exact size of the defect when knowing the distance between the glass sheet 110 and the sensor 112.

Inspection system 100 also has several advantages as described below.

Inspection system 100 has an optical geometry (angle of incidence of light / angle of reflection of light) that provides a virtual or equivalent depth of field in orders of inches rather than millimeters. For large LCD glass sheets (eg 2 × 2) that cannot be easily handled or transported, this means that the sensor can change in inches relative to the glass surface and the incomplete elements are still detectable and measurable.

The inspection system 100 uses a transmission laser geometry that very effectively obtains light on the sensor 112. Other shapes using small high speed sensor elements lack light to render detection of incomplete elements from 5 to 100 microns.

Inspection system 100 may be implemented without cylindrical lens 106. But the results may not be accurate. For example, in this optional embodiment, calculating the presence and size of the incomplete element of the glass sheet 110 requires more processing.

2A and 2C, three diagrams relating to the second embodiment of the inspection system 200 according to the present invention are shown. 2A shows a laser line passing through a cylindrical lens 206 that reflects all rays of the laser line 204 with parallel light 208 of the beam transmitted through the glass sheet 210 at an angle as close to vertical as possible. An inspection system 200 for generating a diode laser is shown. During this process, a portion (about 4%) of the light beam 208 is reflected toward the front of the glass sheet 210 and a portion (about 4-5%) of the light beam 208 is toward the back of the glass sheet 210. Reflected. The two reflected light beams 211 are received by the line-scan sensor 212. Since the light beams 208 are strongly aggregated, the two reflected light beams 211 allow the sensor 212 and a computer (not shown) to produce an image of the interference pattern.

As shown in FIG. 2A, even when the beam of agglomerated light 208 is directed to the glass sheet 210, there is reflection at the front and back of the glass sheet 210, the same forming a fringe pattern. Or generate two wavelengths with different phases (see FIG. 2B). The fringe pattern may be changed by a change in thickness or a change in the refractive index of the glass sheet 210. The fringe pattern is formed in the north-south-direction when there is a small change in the thickness and / or refractive index of the glass sheet 210. And, if there are a large number of east-west fringe patterns per unit area, it indicates a more dramatic change in thickness and / or a more dramatic change in refractive index. As such, the aggregated light 204 generated by the laser 202 allows changes in thickness and refractive index to be detected by the sensor 212 and a mapped computer (not shown). The computer can also be used to increase the accuracy of measuring the change in refractive index or thickness of the glass sheet 210 by averaging the columns of the fringe pattern and finding the lowest and highest points of the sum (the lowest and highest points There is a phase difference of 90 ° and represents a thickness change of one half of the wavelength of light used for measurement). In addition, it can reduce the size by one tenth of the wavelength by dividing it into ten between the lowest and highest points.

Two exemplary interference patterns are shown in FIGS. 2B and 2C. In FIG. 2B, each fringe of the interference pattern represents a change in thickness of the glass sheet 210 equal to 1.5 times the wavelength of the light beam 204. In FIG. 2C, the line-scan-CCD producing the image shows the contents in the glass sheet 210. The central portion of this image reflects the dark content of 192 microns. The image also includes some fringes of the central portion. These fringes indicate a change in refractive index and / or thickness caused by the dark inclusions in the glass plate 210.

As the two reflected light beams 211 move through the space at intervals of the wavelength 1/2 of the laser light 204 they are in phase or different (adding intensities and subtracting intensitieis). It is possible to generate these images because they form a coherent waveform. For example, when the ultraviolet laser is used at a wavelength of 400 nm, a bright area can be seen at each 200 nm and a dark area at 200 nm intervals can be seen. The dark and bright areas are separated by about 1/6 of the light 211 wavelength. If ultraviolet region light 211 is used, this light and dark separation will be 66 nm. Because of this phenomenon, sensor 212 can be used for reflection of bright field scanning (RBF) shapes, Cancer fringe patterns can be detected. And, by observing such fringe patterns, light fringes (or female fringes) can be counted and 1/3 of the wavelength of the light 211 can be multiplied by the number to determine the thickness variation of the glass sheet 210. In general, such analysis alone cannot determine whether the fringe pattern change is due to a change in thickness or a change in refractive index. However, if you have experienced the glass manufacturing process, you will be able to analyze the interference pattern and determine what causes the unique fringe pattern.

The inspection system 200 can measure distortion as a percentage of the wavelength of the laser light 204. This is possible because the fringe pattern is caused by the interference of two waveforms that are the same or different phases as they move through space at intervals of 1/3 of the wavelength of the laser light 204. The highest density of the fringes (lightest areas) can be associated with 0 ° and the lowest density (darkest areas) can be associated with 90 °. Then, it can be inferred that the point of the fringe pattern will be 45 ° in this example in the middle between the lightest and darkest areas because it corresponds to 1/12 of the wavelength of the light 204. And for an ultraviolet region 400 nm laser, for ultraviolet region light (404 nm) this would be about 30 nm. This is why fringe patterns can be translated to 1/12 of a fringe.

The inspection system 200 has several other advantages described below.

If the light 204 angle of incidence can be kept relatively close to the normal of the glass sheet 210, this optical shape can produce a pseudo depth of field that is orders of magnitude greater than millimeters. For large glass sheets (eg 2 × 2) that cannot be easily handled or transported, the sensor is variable in inches relative to the glass surface, and incomplete elements can still be detected and measured. The degree of freedom obtained with this scanning setup allows the glass sheet to be scanned when transported in a standard process transport system.

The inspection system 200 can measure not only sheet thickness but also fine incomplete elements without precise placement of the glass sheet.

Inspection system 200 generates local information as to whether the imperfections distort the surface of the sheet and whether such distortion can be measured in percent of the wavelength of the laser light used for scanning.

The fringe pattern generated by the inspection system 200 can be analyzed, and then a comprehensive change in the thickness of the glass sheet 210 can be determined.

Inspection system 200 enables detection and measurement of refractive index or thickness changes in inclusion areas.

The inspection system 200 may detect a change in refractive index or thickness indicative of itself in a pattern through the field of view of the incomplete element in the draw direction of the glass sheet 210.

The inspection system 200 may be implemented without the cylindrical lens 206 but the results may not be accurate. For example, in this optional embodiment, more processing may be required to calculate the refractive index or thickness of the glass sheet 210.

3A-3E, five diagrams of the inspection system 300 according to the third embodiment of the present invention are shown. 3A shows an inspection system 300 that includes an illuminator 304 used to identify the stress of the sensor 302 and the glass sheet 306. In this example, illuminator 304 includes a lens 308 (optical) that emits polarized light past the laser 306 and the area of the moving glass sheet 306. Sensor 302 (e.g., tri-linear sensor 302) comprises three rows of detectors 312a and 312b for receiving polarized beam 310b passing through organic sheet 306 and 312c) (see FIG. 3B). In this example, the polarization beam 310a is 3-5 "wide. The sensor 302 is disposed about 2" away from the moving glass sheet 306.

As shown in FIG. 3B, the first row 312a of the CCD detector is blocked / covered with a first polarization coating 314a that polarizes the incident light 310b in a zero degree orientation. The second column 312b of the CCD detector is blocked / covered with a second polarization coating 314b that polarizes the incident light 310b in a 120 degree orientation with respect to the CCD detector 312a. The third column 312c of the CCD detector is blocked / covered with a third polarization coating 314c that polarizes the incident light 310b in a 240 degree orientation with respect to the CCD detector 312a. Optionally, inspection system 300 may be matched with polarizing coatings 312a, 312b and 312c, which may be any angle if the relative angle difference between them is 120. Changing the shape of the relative angle difference of 120 degrees decreases the accuracy of the inspection system 300 but still operates. Angles such as 15 degrees, 135 degrees and 255 degrees will work as well as at 0 degrees, 120 degrees and 240 degrees because the relative angle difference is 120 degrees. Angles such as 15 degrees, 160 degrees and 230 degrees will work but will not give an accurate answer. As a result, the relative angular difference should be close to 120 degrees and any deformation from this ideal shape would result in an inspection system 300 that is acceptable but gives less acceptable results.

In operation, when sensor 302 is illuminated with polarization 310b, the output from each column of CCD detectors 312a, 312b, and 312c is polarized with the polarization filter angle associated with each column of CCD detectors 312a, 312b, and 312c. It is the cross product of the vector of the input of 310b. As such, when polarization 310a passes through glass sheet 306 containing a detectable amount of stress, the light beam generates a signal from three line-scan rows of CCD detectors 312a, 312b and 312c. The polarization angle of 310b is changed in proportion to the amount of stress. This signal is used to identify the stress of the glass sheet 306.

As such, when there is no stress on the viewing sheet 306, the polarization angle of the received polarization 310a will have the same angle as the light 310a emitted by the laser 306. And if there is a small amount of stress in the glass sheet 306, this stress is light in small amounts that can be measured and calculated by analyzing the output from the new rows of polarized CCD detectors 312a, 312b and 312c. Will change the polarization angle of 310b. And when there is a large amount of stress on the glass sheet 306, the polarization angle of the light 310b passing through the glass sheet 306 will be changed greatly, and this change in polarization is again polarized CCD detectors 312a, 312b. And 3 columns of 312c).

It can be considered that it is possible to uniquely identify the polarization angle using only two CCD detectors (eg, 312a, 312b) including orthogonal polarizers, but only in the absence of specificity. To illustrate this, reference is made to FIGS. 3C and 3D where two different polarization angles of the two incoming waveforms change with the same amount of polarization when fired into two vertically polarized CCD detectors 312a and 312b. It is not possible to individually identify their polarization angle for these two waveforms. The problem can be solved by the addition of the third column 312c (eg,) of the CCD detector.

3E shows an example of a portion of the LCD glass 306 that bends dynamically when a line-scan image is generated by the sensor 302. Over time, this change in fringe pattern indicates a change in stress. In general, the amount of stress that can vary over the area of the glass sheet 306 depends on how the glass sheet 306 is formed as well as many peripheral effects.

Inspection system 300 has several advantages as follows.

Inspection system 300 does not require moving parts.

Inspection system 300 is suitable for on-line measurement.

Inspection system 300 may be used to create a stress map of all areas of LCD glass sheet 306. For example, a complete stress map of the glass sheet 306 may be created, and a plurality of sensors 302 arranged in a line are used to form a sensor as long as the size of the glass sheet and the signals generated from the sensors With the aid of a computer, it can be used to create a stress image of the entire glass sheet 306.

As described above, the inspection system 300 may be implemented without the cylindrical lens 308, but the results may not be accurate. For example, more processing may be required to calculate / identify the stress of the glass sheet 306 in this optional embodiment.

4A-4C are three diagrams of an inspection system 400 according to a fourth embodiment of the invention. 4A shows a color multi-line sensor 402 and a plurality of illuminators (lasers) 404a, 404b, 404c, 404d (four shown) used to identify imperfections inside or outside the glass sheet 406. An inspection system 400 is shown that includes. In this example, the multi-line-scan sensor 402 has a plurality of rows of CCD detectors 404a, 404b, 404c, 404d each covered with spectral filters 414a, 414b, 414c, 414d (FIG. 4B). Reference). And four other illuminators 404a, 404b, 404c, 404d are colored light beams 416a, 416b, 416c, 416d having energy within one energy band of the filtered rows of CCD detectors 412a, 412b, 412c, 412d. Emits. 4B and 4C show how each spectral filter 414a, 414b, 414c, 414d passes through only a corresponding row of CCD detectors 412a, 412b, 412c, 412d through a single row of specific color (wavelength) light beams 416a, 416b, 416c, 416d are shown and block other light beams 416a, 416b, 416c, 416d.

In the inspection system 400 shown in FIGS. 4A-4C, the red illuminator 404a emits the red light beam 416a through the lens 418 and the energy band of the red light beam 416b through the glass sheet 406. And goes above the column 412a of the CCD detector that is filtered to accommodate. In this example, the CCD detector 412a is sensitive to the fine content of the glass sheet 406. The green illuminator 406b emits a green light beam 416b that is directed to the rows 412b of the filtered CCD detector and to be reflected off the glass sheet 406 to receive the green light beam 416b energy band. In this example, CCD detector 412b is sensitive to inclusions and glass thickness. The blue illuminator 406c passes through the grating 420 and then through the glass sheet 406 to the column 412c of the CCD detector to receive the energy band of the blue light beam 416c. ). In this example, CCD detector 412c is sensitive to streaks and variations in refractive index or reflections of glass sheet 406. Then, the gray (infrared) illuminator 406d passes through the lens 424 and then through the glass sheet 406 through the glass sheet 406 to a row 412d of CCD detectors filtered to receive the energy band of the gray (IR) light beam 406d. Emits a gray light beam 416d. In this example, the CCD detector 412d allows to measure the position of the incomplete element of the glass sheet 406. Similar to this approach, inspection system 400 may be designed to detect other characteristics of glass sheet 406 using light beams having different energy bands, such as infrared and ultraviolet energy bands. As can be seen, the inspection system 400 with one sensor 402 can measure the shape of the glass sheet 406 and many properties for contaminants.

For all practical purposes, it is not important which wavelength of light 416a, 416b, 416c, 416d is used to measure what type of property (eg, fine content, glass thickness). For example, a red light beam 416a and CCD detector 412a may be used to detect refractive index changes instead of the micro content of glass sheet 406. Again, thereafter, for example, color spectrum filters 414a, 414b, to maintain the red light 416a emitted from the red laser 404a from what is seen by the non-red CCD detectors 412b, 412c, 412d. 414c, 414d) are used. This is because different colors of light 416a, 416b, 416c, 416d interfere with information generated by other properties (shape) from each characteristic (shape--incidence angle of light and angle of reflection of light on sensor 402). Means that it can be used to distinguish the information provided by it.

Four lasers 406a, 406b, 406c, 406d as long as they can be distinguished by spectral filters 414a, 414b, 414c, 414d positioned in front of the four columns 412a, 412b, 412c, 412d of the CCD detector. Whatever the wavelength is, it doesn't matter too. As such, the wavelengths of the lasers 406a, 406b, 406c, 406d may be selected to match lasers such as 404 nm, 750 nm, 870 nm and 950 nm which are inexpensive and commercially available. In addition, the wavelength of light can be carried out at any useful wavelength from 200 nm to 2000 nm.

Inspection system 400 has several other advantages as described below.

Spatial coordination: all measurements are made from one multi-scan sensor 402 and thus between the different views provided by each of the other line-scan-arrays 412a, 412b, 412c, 412d. It is much easier to harmonize spatial relationships.

Reduced cost: Here, two or more rows of CCD detectors 412a, 412b, 412c, 412d can be implemented on one substrate, meaning one installation device, one interface and possibly one lens. .

Reduced size: In this case, the inspection system 400 may have one sensor 402 instead of two or more sensors that take up a lot of space.

5A-5C, three diagrams of inspection system 500 according to a fifth embodiment of the present invention are shown. Inspection to scan for changes in materials (eg, paper, plastic, iron, aluminum, and glass sheets) to classify and detect aberrations as they occur to get good control and process information It is well known today that systems can be used. However, this scanning process detected by the inspection system may occur during the manufacturing process and may be confused by foreign particulates attached to the surface of the material. For transparent materials such as glass sheets, when particulates (eg, dust, dirt, glass chips) are placed on the surface of the material, the inspection system can identify the particulates (containings) located inside the material. . This leads to inaccuracies in the results provided by the inspection system. In fact, in some processes, the number of surface particulates can be 10 to 100 times the internal particulates, which tends to make the scan results meaningless. Inspection system 500 of the present invention detects this problem by detecting incomplete element 502 contained within transparent material 504 (eg, glass sheet 504) without detecting surface particulates 506. Process.

As shown in FIGS. 5A and 5B, inspection system 500 employs an illuminator 508 that emits light 510 to glass sheet 504 at a particular angle. The angle is selected such that a portion of the light 510 is internally reflected into the glass sheet 504 moving away from the location where the light 510 of the moving glass sheet 504 enters and exits. Then, the light 510 reflected by the surface particles 506 positioned at the entrance and exit of the moving glass sheet 504 is not detected and the light 510 reflected by the internal defect 502 is detected. The line-scan camera 512 is placed at one location to focus on the area. These two diagrams show a line-scan camera 512 where light 510 from the illuminator 508 is placed far from the point on the moving glass sheet 504 entering and exiting the glass sheet 504. Again, the line-scan camera 512 at that location can detect and focus internal defects 502 without detecting surface particulates 506.

In an alternative embodiment, the line-scan camera 512 may be replaced with a line-scan sensor, time delay integration (TDI) and contact sensor. And illuminator 508 may be a laser, laser line, or other illuminator, such as fluorescence 508a (see FIG. 5C). When an illuminator such as fluorescent light 508a is used, light 510a may be drawn from entering or exiting the moving glass sheet 504 at the point of the glass sheet 504 that the line scan camera 512 is inspecting. It may be necessary for shield 514 to be used and disposed so that light 510a may be internally reflected underneath the moving glass sheet 504 at the same time as it is blocked.

Inspection system 500 has several other advantages, one of which is described below.

In addition to the glass sheet 504, the inspection system 500 can be used to inspect other product types such as glass webs and other transparent materials in the form of plates or webs.

6A-6D, four diagrams of an inspection system 600 according to a sixth embodiment of the present invention are shown. It is well known to those skilled in the art of glass manufacturing that a slight change in refractive index and / or thickness of the glass sheet 602 occurs when the glass sheet 602 can reflect the collimated light to a degree that the difference in collimation is measurable. . This effect is visible to the naked eye when looking at the glass sheet 602 (LCD display 602), which is considered an incomplete element. 6A and 6B illustrate a flat, undesirable glass sheet 602 where light 604 is emitted by a point light source 606 (laser) and reflects light 604 representing a light and dark streaked white background 608. This effect is shown when delivered through. The inspection system 600 of the present invention is capable of detecting minute changes in the refractive index and / or thickness of the glass sheet 602 (or other flat transparent material). It is important to detect these undesirable glass sheets 602 before they are used in products such as LCD displays.

6C shows an inspection system 600 that includes a laser 610 that produces a fan of light 612 of relatively equal intensity. Inspection system 600 also includes a collimating lens 614 that scatters light 612 from the pan into a line of parallel light 616. In this example, light 616 is incident on grating 618 having a fill factor of 50% and a period of 500 line pairs per inch. The grating 618 forms a series of dark lines 622a and bright lines 622b that are projected through the glass sheet 602 (eg, LCD glass sheet) to the line-scan CCD sensor 620. do. In this example, the distance between the grating 618 and the glass sheet 602 is 2 ". The distance between the grating 618 and the sensor 620 is 4". And the width of the parallel light beam 616 is 3 "to 5".

When a piece of a very flat " reference " glass sheet 602 having a constant thickness and refractive index is analyzed by the inspection system 600, a reference waveform such as that shown in waveform 1 at the top of FIG. Can be created and stored. Waveform 1 shows the alternating light and dark areas created by the presence of grating 618. The computer uses waveform 1 as a reference or a reference to compare the waveform of other glass sheets 602. For example, if a relatively good glass sheet 602 is located between the grating 618 and the sensor 620, a wave form, such as waveform 2, may be generated. The bright areas of each waveform 1 and 2 are the same top cut shape and subtract waveform 2 from the two waveforms 1, resulting in the same waveform as waveform 3. Waveform 3 shows a small blip at the edge of the square wave, which may have a positive or negative magnitude. The width of the flip is relatively small because the waveform 1 associated with the reference glass sheet 602 is approximately the same as the waveform 3 associated with the high quality glass sheet 602. Waveform 4 is the integration of the blips shown in waveform 3 generated by the positive edges of each waveform (blips generated at negative edges are ignored). In this case, since the good quality glass sheet 602 has almost the same quality as the reference glass sheet 602, the integration of the blips shown in the waveform 4 is small. Details regarding the relationship between the blips are described in detail below when comparing the non-homogeneous glass sheet 602 with the waveform of the reference glass sheet 602.

Waveform 6 is generated after inspection of the heterogeneous glass sheet 602 with varying refractive indices or thickness variations. Regions with varying refractive indices or inconsistent thickness cause the direction of light 616 to reflect or change, which shifts the edge of the waveform from side to side. When the resulting waveform moves to the right, the light rays 616 traveling through the heterogeneous glass sheet 602 bend to the right. And similarly the light beam 616 bends to the left when the waveform moves to the left. When subtracting the waveform 6 from the waveform 5 (same as the reference waveform 1), a waveform 7 indicating the change in thickness, shape and / or refractive index can be obtained. The "dark" shaded area of waveform 7 is the blip created by the positive edge of waveform 5. And the “bright” shaded region of waveform 7 is the blip created by the negative edge of waveform 5. The width of the blips indicates the magnitude of the change in direction of the light 616 as it moves through the heterogeneous glass sheet 602. The direction of flip of waveform 7, which is negative or positive, determines the change in direction of light 616 when compared to the edge of waveform 5. For example, the positive edge ("dark" blip) of waveform 5 associated with the positive blip indicates that the light beam is bent to the left. And the negative " dark " blip of waveform 5 indicates the light beam bends to the right. If a line is shown from the top of all "dark" blips, waveform 8 is generated. If the overall value of waveform 8 is positive, it indicates that the ray is bent to the left, and if it is almost zero (zero) it is indicated that the ray is not bent, and if it is negative it is indicated to bend to the right. Basically, when the value of the waveform 8 becomes greater than zero, changes in the thickness, shape and / or refractive index of the non-uniform glass sheet 602 become less desirable.

Inspection system 600 has several advantages as described below.

Inspection system 600 can be used to measure fine streaking of glass sheet 602 caused by a change in refractive index, a change in thickness, or a change in shape of glass sheet 602. This produces direction and relative size information and produces one thousand records per inch across the surface of the glass sheet 602.

7A-7D, four diagrams associated with the inspection system 700 according to the seventh embodiment of the present invention are shown. Although the techniques described above used in inspection systems 100-600 to scan fine incomplete elements are useful for detecting incomplete elements in space due to the fact that they have a relatively large depth of field, such large depth of field ( For example, 2 inches) means that these scanning techniques are not good at measuring the distance of incomplete elements away from the sensor. And in the case of LCD glass, an inspection system that can determine if a defect is on or near the A or B side of the LCD glass can be useful. This performance may be beneficial during the coating process of LCD glass because it is more sensitive to defects on the other side than defects on one side of the glass sheet. Therefore, it is important to determine the defective side because the defect is not inadequate if it is on the B side but can be very inadequate if placed on or near the A side. The inspection system 700 described below can determine the position in the Z direction relative to the longitudinal direction of the glass sheet.

7A shows two laser line light sources and two line scan arrays each having different wavelengths to determine the relative positions of two defects 706 and 708 located on the same horizontal plane of the glass sheet 710 in this example. Side view of inspection system 700 using sensor 706 with 712a, 712b. The figure shows the glass sheet 710 moving upward at a constant speed V at a fixed distance D from the sensor 704. The two line-scan arrays 712a, 712b are known separation distances d. And, each line-scan array 712a, 712b is sensitive to different wavelengths of light. For example, lower line-scan array 712b is sensitive to red light 714a emitting from red laser 702a. And, the upper line-scan array 712b is sensitive to the green light 714b emitted by the green laser 702b. The upper line-scan array 712a is illuminated with each alpha A relative to the vertical of the sensor 704. And the lower line-scan array 712b is illuminated by the lower laser 702a at an angle perpendicular to the glass sheet 710 and the sensor 704. In this example, CCD line scan sensor 704 creates a new pixel every 5 microns and images of defects 706 and 708 are recorded in one or more scans. FIG. 7A shows a snapshot of inspection system 700 when defects 706 and 708 block light 714a from laser 702a at time zero.

FIG. 7B is a snapshot of inspection system 700 at time T1 when defect 708 on the A side of glass sheet 710 blocks light 714b emitted from laser 702. CCD line scan sensor 704 records an image of this defect 708 in one or more of its pixel scans.

FIG. 7C is a snapshot of inspection system 700 at time T2 when defect 706 on B surface of glass sheet 710 blocks light 714b emitted from laser 702b. CCD line scan sensor 704 records an image of this defect 706 in one or more of its pixel scans.

7D shows a composite of all previous sensor scans, which show three images of defects 706 and 708. First, it shows images of the A side defect 708 and the B side defect 706 superimposed on each other because they are detected at the same time zero. Secondly, as it passes through the light beam 714b emitted from the laser 702b at time T1, it shows an image of the A plane defect 708. Third, when passing through the light beam 714b emitted from the laser 702b at time T2, an image of the B plane defect 706 is shown.

The distance traveled by the A side defect 708 can be calculated by counting the number of line scans generated between time 0 and time T1 and multiplying this number by 5, the size of the pixel in microns in this example. As such, the distance traveled by the B plane defect 706 can be calculated by counting the number of line scans generated between time 0 and time T2 and multiplying this number by 5, the size of the pixel in microns in this example. This is because the time taken for the B side defect 706 to pass through the light beam 714b is longer than the A side defect 708, there will be more scan lines and a longer distance for the B side defect 706 will be calculated. will be.

Thereafter, the distance from the sensor 704 of the A surface defect 708 can be calculated by multiplying the distance of the A surface defect 708 by the tangent of the angle A. FIG. Similarly, the distance from the sensor 704 of the B surface defect 706 can be calculated by multiplying the tangent of the angle A by the distance the A surface defect 706 travels. It should be understood that this type of distance calculation may be made for one or more located on the surface of the glass sheet 710.

In an alternative embodiment, the inspection system may be used to determine the location of the defect by monitoring the flight time, which is the time it takes for the defect to move in front of the first laser 702a to cross the second laser 702b. 700) can be used.

Case 1: The travel time of the A side defect 708 can be calculated as follows.

t _a = (d + D * tan (A)) / V

Case 2: The travel time of the B side defect 706 can be calculated as follows.

t _b = (d + (D + T (n _a / n _g )) * tan (A)) / V

In the above equation, n _a is the refractive index of air and n _g is the refractive index of glass sheet 710.

Case 3: The travel time of a defect (not shown) located at point P inside glass sheet 710 can be calculated as follows.

t _p = (d + (D + P (n _a / n _g )) * tan (A)) / V

In order to find the position P, the equation becomes

P = n _g * ((t _p * V)-d-D * tan (A)) / (n _a * tan (A))

In one example, the angle of the laser 702b is 20 degrees, the speed of the glass sheet 710 is equal to 3 inches per second, the distance from the sensor 704 of the glass sheet 710 is 2 inches, and the refractive index of air is It will be 1, the distance between the line-scan arrays 712a, 712b will be 90 microns, the pixel size is 5 microns, and the refractive index of the glass is 1.5. The calculation of three different positions of the glass sheet 710 can then be performed: (1) P is at plane A, which is zero; (2) inside a glass where P is 300 microns; And (3) at side B where P is 700 microns. The travel time at these three positions is as follows.

On the B side: Movement time = .243827 seconds

* At 300 microns: Movement time = .243827 + .00095 = .244777 seconds

On the A side, movement time = .243827 + .00220 = .246027 seconds

Then, in order to calculate the location of the nodule, it is necessary to know the precision that the inspection system 700 can measure and in this example the sensor 702 can measure at 5 micron pixels. To solve this problem, the scan should be scanned at the same rate as the speed (V) of the glass sheet 710 divided into a pixel size of 5 microns, which results in 15,240 scans per second. By taking the reciprocal of this number, you can get time between scans or 0.0000656 seconds per scan. This gives a 33 scan difference between the travel time generated from the B side to the A side for the 700 micron thick piece of glass sheet 710. As can be seen, these measurements are accurate enough to give good location information.

Sensors that can be used in any of the inspection systems 100-700 described above can be such as Kodak KLI 14441 sensors and Kodak KLI 4104 sensors. However, special types of sensors are not important. Importantly, the sensor has multiple arrays of line-scan elements that help coordinate and coordinate information from multiple camera perspectives or multiple camera shapes.

Although several embodiments of the present invention have been described in detail with reference to the drawings, the present invention is not limited to the embodiments, and various modifications, variations, and modifications are made without departing from the spirit of the invention proposed and defined in the claims of the present invention. It should be understood that substitution may be made.

According to the present invention, it is possible to effectively detect incomplete elements existing on and in the surface of transparent flat materials.

Claims (66)

In a method for inspecting incomplete elements of transparent and flat materials, Using an illuminator that emits a light beam; Using a first lens to receive the light beam and emitting parallel light beams through a portion of the transparent and flat material; Using the line-scan sensor to receive a parallel light beam passing through a portion of the transparent and flat material and to focus the incomplete element of the transparent and flat material without a second lens disposed in front of the line-scan sensor step; Method for inspecting the incomplete element of the transparent and flat material comprising a. The method of claim 1, And said parallel light beam passing through a portion of said transparent and flat material is constituted by said incomplete element and the physical properties of said transparent and flat material. The method of claim 1, Wherein said line-scan sensor has a depth of field greater than 1 inch. The method of claim 1, The line-scan sensor is analyzed by a computer that generates an image indicative of a Fresnel effect associated with the parallel light beam passing through the transparent and flat material that enables detection of an incomplete element of the transparent and flat material. A method for inspecting incomplete elements of transparent and flat materials, characterized by outputting a signal. The method of claim 1, The line-scan sensor is analyzed by a computer to generate an image indicative of an interference pattern associated with the parallel light beam passing through the transparent and flat material that makes it possible to detect a change in refractive index or thickness of the transparent and flat material. A method for inspecting incomplete elements of transparent and flat materials, characterized by outputting a signal. The method of claim 1, And said transparent and flat material is a glass sheet. An inspection system for detecting incomplete elements of transparent and flat materials, An illuminator emitting a light beam; A first lens that receives the light beam and emits a parallel light beam through a portion of the transparent and flat material; A line-scan sensor that receives the parallel light beam passing through a portion of the transparent and flat material and focuses on the incomplete element of the transparent and flat material without a second lens disposed in front of the line-scan sensor; Inspection system for detecting an incomplete element of a transparent and flat material comprising a. The method of claim 7, wherein And the parallel light beam passing through a portion of the transparent and flat material is constituted by the incomplete element and the physical properties of the transparent and flat material. The method of claim 7, wherein And said line-scan sensor has a virtual depth of field of greater than one inch. The method of claim 7, wherein The line-scan sensor is analyzed by a computer that generates an image indicative of a Fresnel effect associated with the parallel light beam passing through the transparent and flat material that enables detection of an incomplete element of the transparent and flat material. Inspection system for detecting incomplete elements of transparent and flat material, characterized in that it outputs a signal. The method of claim 7, wherein The line-scan sensor is analyzed by a computer to generate an image indicative of an interference pattern associated with the parallel light beam passing through the transparent and flat material that makes it possible to detect a change in refractive index or thickness of the transparent and flat material. Inspection system for detecting incomplete elements of transparent and flat material, characterized in that for outputting a signal. The method of claim 7, wherein The inspection system for detecting an incomplete element of the transparent and flat material, wherein the transparent and flat material is a glass sheet. An inspection system for detecting incomplete elements of transparent and flat materials, An illuminator emitting a light beam; A first lens that receives the light beam and emits a parallel light beam toward a portion of the transparent and flat material; A line-scan sensor that receives the parallel light beam reflected from the front and back of the transparent flat material and focuses on an incomplete element of transparent and flat material without a second lens disposed in front of the line-scan sensor; Inspection system for detecting an incomplete element of a transparent and flat material comprising a. The method of claim 13, And the parallel light beams reflected from the front and back surfaces of the transparent and flat material are constituted by the incomplete element and the physical properties of the transparent and flat material. The method of claim 13, And the line-scan sensor has a depth of field greater than 1 inch. The method of claim 13, The line-scan sensor is transparent and characterized in that it outputs a signal analyzed by a computer to generate a bright field fringe pattern image that makes it possible to detect incomplete elements of the transparent and flat material. Inspection system for detecting incomplete elements of flat materials. The method of claim 13, The line-scan sensor outputs a signal analyzed by a computer that generates a bright field fringe pattern image that makes it possible to detect a change in refractive index or thickness of the transparent flat material. Inspection system for detecting incomplete elements of transparent and flat materials. The method of claim 13, The inspection system for detecting an incomplete element of the transparent and flat material, wherein the transparent and flat material is a glass sheet. In a method for inspecting incomplete elements of transparent and flat materials, Using an illuminator that emits a light beam; Using a first lens to receive the light beam and emitting parallel light beams toward a portion of the transparent and flat material; The line-scan sensor is adapted to receive parallel light beams reflected from the front and back of the transparent flat material and to focus the incomplete elements of the transparent and flat material without a second lens disposed in front of the line-scan sensor. Using; Method for inspecting the incomplete element of the transparent and flat material comprising a. The method of claim 19, And said parallel light beam reflected from the front and back of said transparent and flat material is constituted by said incomplete element and the physical properties of said transparent and flat material. The method of claim 19, Wherein said line-scan sensor has a depth of field greater than 1 inch. The method of claim 19, The line-scan sensor is transparent and characterized in that it outputs a signal analyzed by a computer to generate a bright field fringe pattern image that makes it possible to detect incomplete elements of the transparent and flat material. How to check for incomplete elements of flat materials. The method of claim 19, The line-scan sensor outputs a signal analyzed by a computer that generates a bright field fringe pattern image that makes it possible to detect a change in refractive index or thickness of the transparent flat material. How to check for incomplete elements of transparent and flat materials. The method of claim 19, And said transparent and flat material is a glass sheet. In the inspection system for detecting the stress of transparent and flat material, sensor; An illuminator that emits a polarizing beam towards the sensor through a portion of the transparent and flat material, The sensor is transparent by using a first row of detectors blocked by a first polarizer, a first row of detectors blocked by a first polarizer, and a first row of detectors blocked by a first polarizer. Receive a polarizing beam passing through the flat material; When there is a detectable degree of stress in the transparent and flat material, when the polarizing beam passes through the transparent and flat material that can be detected and measured by three rows of detectors, the stress is at the polarization angle of the polarizing beam. Inspection system for detecting the stress of transparent and flat material, characterized in that the deformation. The method of claim 25, The first polarizing plate is a 0 ° polarizing plate coating the first row of the detector; The second polarizer is a 120 ° polarizer that coats a second row of the detector; And the third polarizer is a 240 ° polarizer for coating a third row of the detector. The method of claim 25, And a plurality of sensors for enabling the generation of stress maps for all of the transparent and flat materials. The method of claim 25, The inspection system for detecting stress of the transparent flat material, wherein the transparent and flat material is a glass sheet. In the method of testing the stress of a transparent and flat material, Using an illuminator to emit a polarizing beam towards the sensor through the transparent flat material; Passing through the transparent and flat material by using a first row of detectors blocked by a first polarizer, a first row of detectors blocked by a first polarizer, and a first row of detectors blocked by a first polarizer Using the sensor to receive a polarizing beam; When there is a detectable degree of stress in the transparent and flat material, when the polarizing beam passes through the transparent and flat material that can be detected and measured by the three rows of detectors, the stress is deflected by the polarizing beam. A method for testing the stress of transparent and flat materials characterized by deforming a wide angle. The method of claim 29, The first polarizing plate is a 0 ° polarizing plate coating the first row of the detector; The second polarizer is a 120 ° polarizer that coats a second row of the detector; And said third polarizing plate is a 240 [deg.] Polarizing plate coating a third row of said detectors. The method of claim 29, And using a plurality of sensors to enable generation of stress maps for all the transparent and flat materials. The method of claim 29, Wherein said transparent and flat material is a glass sheet. There is an inspection system for detecting other types of incomplete elements on the surface or inside of transparent and flat materials, sensor; A first illuminator emitting a first light beam toward the sensor having a specific energy band passing through or reflecting off a portion of the transparent flat material; And A second illuminator emitting a second light beam toward the sensor having a specific energy band passing through or reflecting off a portion of the transparent flat material; Including, The sensor has a first spectrum of detectors covered with a first spectral filter designed to receive only the first light beam by a first row of detectors and a second spectrum designed to receive only the second light beam by a second row of detectors. By using a second row of detectors covered with a filter to receive the first and second light beams passing through or reflecting off a portion of the transparent and flat material, Each row of detectors enables detection of other types of incomplete elements on or within the surface of the transparent flat material. The method of claim 33, wherein The inspection system further comprises an additional illuminator and a thermal and spectral filter of the additional detector. The method of claim 33, wherein The incomplete element, Cord; Streaak; Fine inclusions; And Change in refractive index; Inspection system comprising a. The method of claim 33, wherein And the transparent flat material is a glass sheet. A method for inspecting other types of incomplete elements on or within a transparent and flat material, Using a first illuminator to emit a first light beam towards the sensor having a specific energy band passing through or reflecting off a portion of the transparent flat material; Using a second illuminator to emit a second light beam toward the sensor having a specific energy band passing through or reflecting off a portion of the transparent flat material; A first column of detectors covered by a first spectral filter designed to receive only the first light beam by a first column of detectors and a second spectral filter designed to accept only the second light beam by a second column of detectors Using the sensor to receive the first and second light beams passing through or reflecting off a portion of the transparent flat material by using a second row of true detectors; Including, Each row of detectors enables detection of other types of incomplete elements on or within the surface of the transparent flat material. The method of claim 37, And further illuminators and additional detector heat and spectral filters are used to detect more types of incomplete elements on or within the transparent and flat material. The method of claim 37, The incomplete element, Cord; Streaak; Fine inclusions; And Change in refractive index; Inspection method comprising a. The method of claim 37, And the transparent flat material is a glass sheet. An inspection system for detecting incomplete elements inside transparent and flat materials, An illuminator that emits the light beam at a certain angle towards the transparent and flat material such that a portion of the light beam is internally reflected to the portion of the transparent and flat material that is located far from where the light beam of the transparent and flat material originally enters and exits ; And Focusing the portion of the transparent and flat material positioned away from where the light beam of the transparent and flat material originally enters and exits, and is transparent and flat material without being influenced by light reflected on the surface particulates of the transparent and flat material A sensor for detecting light reflected by an incomplete element in the interior of the sensor; Inspection system comprising a. The method of claim 41, wherein The illuminator blocks light internally within the transparent and flat material while blocking light from entering and exiting the transparent and flat material at a location where a laser, laser line and sensor are focused on the transparent and flat material. An inspection system, characterized in that it comprises at least one of a light source for which a shield is used to allow it to be used. The method of claim 41, wherein And the sensor comprises at least one of a line-scan sensor, a line-scan camera, a time delay integration sensor and a contact sensor. The method of claim 41, wherein And the transparent flat material is a glass sheet. In a method for inspecting an incomplete element inside a transparent and flat material, An illuminator for emitting the light beam at a certain angle toward the transparent and flat material such that a portion of the light beam is internally reflected by a portion of the transparent and flat material disposed away from where the light beam of the transparent and flat material originally enters and exits Using; And Far from where the light beam of the transparent and flat material originally enters and exits to detect light reflected by an incomplete element inside the transparent and flat material without being affected by light reflected by the surface particulates of the transparent and flat material. Using a sensor for focusing into said portion of transparent and flat material disposed apart. The method of claim 45, The illuminator internally reflects light within the transparent and flat material while blocking light from entering and exiting the transparent and flat material at a location where a laser, laser line and sensor are focused on the transparent and flat material. And at least one of the light sources in which a shield is used. The method of claim 45, And the sensor comprises at least one of a line-scan sensor, a line-scan camera, a time delay integration sensor and a contact sensor. The method of claim 45, And the transparent flat material is a glass sheet. An inspection system for detecting a change in refractive index and / or thickness of a transparent and flat material, An illuminator emitting a light beam; A lens for receiving the light beam and emitting a parallel light beam; A grating receiving the emitted parallel light beam and forming a series of bright and dark lines in directions directed to the transparent and flat material; A sensor receiving a series of bright and dark lines passing through said transparent and flat material and generating an output waveform related to said series of bright and dark lines passing through said transparent and flat material; A processing unit for comparing a reference waveform with the output waveform and generating a difference waveform indicative of a change in refractive index and / or thickness of the transparent flat material; Inspection system comprising a. The method of claim 49, And wherein the difference waveform has at least one blip having a width that indicates the magnitude of one direction change of the light beam as the light beam passes through the transparent and flat material. The method of claim 49, And the transparent flat material is a liquid crystal display (LCD) glass sheet. A method for inspecting changes in refractive index and / or thickness of transparent and flat materials, Using an illuminator to emit a light beam; Using a lens to receive the light beam and emit parallel light beams; Using a grating to receive the emitted parallel light beam and form a series of bright and dark lines in a direction towards the transparent and flat material; Receiving a series of bright and dark lines through the transparent and flat material and using a sensor to generate an output waveform related to the series of bright and dark lines passing through the transparent and flat material; Using a processing unit to compare a reference waveform with the output waveform and to generate a difference waveform indicative of a change in refractive index and / or thickness of the transparent flat material; Inspection method comprising a. The method of claim 52, wherein And wherein the difference waveform has at least one blip having a width that indicates the magnitude of one direction change of the light beam when the light beam passes through the transparent and flat material. The method of claim 52, wherein And the transparent flat material is a liquid crystal display (LCD) glass sheet. An inspection system for detecting the location of a defect on or within a transparent and flat material, A sensor comprising a first row of detectors receiving a first light beam passing through the transparent and flat material and a second row of detectors receiving a second light beam passing through the transparent and flat material; A first illuminator passing through a portion of the transparent flat material and emitting the first light beam having a first wavelength towards the sensor; A second illuminator passing through a portion of the transparent flat material and emitting a second light beam having a second wavelength towards the sensor; And A processing unit for comparing the images received from the first and second rows of the detector and detecting the location of a defect on or in the transparent flat material; Inspection system comprising a. The method of claim 55, Compute the distance traveled by the defect on or within the transparent flat material moving between the sensor and the first and second illuminators, wherein the calculated distance and the first light beam for the sensor By multiplying the tangent of the angle between two light beams, And the processing unit compares the images received from the first and second rows of detectors and detects the location of defects on or within the transparent and flat material. The method of claim 55, The first column of the detector is sensitive to the first light beam and is not sensitive to the second light beam, and the second row of the detector is sensitive to the second light beam and not sensitive to the first light beam. Inspection system. The method of claim 55, And the transparent flat material is a glass sheet. A method for inspecting the location of a defect on or inside a transparent and flat material, Toward the sensor comprising a first row of detectors receiving a first light beam passing through the transparent and flat material and a second row of detectors receiving a second light beam passing through the transparent and flat material Using a first illuminator to pass through a portion of a material and emit the first light beam having a first wavelength; And Using a second illuminator to pass toward the sensor the second light beam passing through a portion of the transparent flat material and having a second wavelength; And Using a processing unit to compare images received from the first and second rows of the detector and to detect the location of a defect on or in the transparent flat material; Inspection method comprising a. The method of claim 59, Compute the distance traveled by the defect on or within the transparent flat material moving between the sensor and the first and second illuminators, wherein the calculated distance and the first light beam for the sensor By multiplying the tangent of the angle between two light beams, And the processing unit compares the images received from the first and second rows of detectors and detects the location of defects on or within the transparent and flat material. The method of claim 59, The first column of the detector is sensitive to the first light beam and is not sensitive to the second light beam, and the second row of the detector is sensitive to the second light beam and not sensitive to the first light beam. Inspection method. The method of claim 59, And the transparent flat material is a glass sheet. An inspection system for detecting incomplete elements of transparent and flat materials, An illuminator that emits a light beam through a portion of the transparent flat material; And A line-scan sensor that receives the light beam passing through the portion of the transparent and flat material and focuses on the incomplete element of the transparent and flat material without a second lens disposed in front of the line-scan sensor; Inspection system comprising a. A method for inspecting incomplete elements of transparent and flat materials, Using an illuminator to emit a light beam through a portion of the transparent flat material; And Using a line-scan sensor to receive the light beam passing through the portion of the transparent and flat material and to focus on the incomplete element of the transparent and flat material without a second lens disposed in front of the line-scan sensor ; Inspection method comprising a. An inspection system for detecting incomplete elements of transparent and flat materials, An illuminator that emits a light beam towards a portion of the transparent flat material; And A line-scan sensor for receiving the light beam reflected from the front and rear surfaces of the transparent and flat material and focusing on the incomplete element of the transparent and flat material without a second lens disposed in front of the line-scan sensor; Inspection system comprising a. A method for inspecting incomplete elements of transparent and flat materials, Using an illuminator to emit a light beam towards a portion of the transparent flat material; And Using a line-scan sensor to receive the light beam reflected from the front and back of the transparent and flat material and to focus on the incomplete element of the transparent and flat material without a second lens disposed in front of the line-scan sensor step; Inspection method comprising a.

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