JP2018189552A - Glass plate, method for inspecting end surface of glass plate, and method for manufacturing glass plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a glass plate more surely that generates an only extremely small amount of glass powders from the end surface by increasing the accuracy of inspecting the end surface.SOLUTION: The method for inspecting an end surface of a glass plate includes a first observation step of enlarging and observing a specific region R of a polished surface S1a formed on an end surface S1 of an inspection glass plate S and acquiring a first enlarged image; a cleaning step of cleaning the specific region R while applying external stimulation to the specific region R; a second observation step of enlarging the specific region R again and acquiring a second enlarged image; and an evaluation step of comparing the first enlarged image and the second enlarged image and counting the number of fine recesses in the specific region R formed after the first observation step.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a glass plate, a glass plate end surface inspection method, and a glass plate manufacturing method.

  High definition is being promoted for flat panel displays (FPD) such as liquid crystal displays, plasma displays, and organic EL displays. Accordingly, a dense electric circuit is formed in the FPD manufacturing process on the glass plate used as the FPD substrate.

  The end surface of a glass plate for FPD is usually subjected to polishing (including grinding) using a grindstone, but the end surface has a microcrack (for example, a microcrack associated with polishing). Cracks often occur. These micro cracks grow with the passage of time, and can cause glass powder (particles) to be generated from the polished surface. Such glass powder has a particle size of about 0.1 to 10 μm, for example. Further, the glass powder is often a hidden glass powder that does not exist at the end face inspection performed after the polishing process, and is easily overlooked in the end face inspection for the glass powder already attached to the end face. As a result, even when an FPD is manufactured using a glass plate that has cleared the end face inspection, the FPD manufacturing defect may be caused by the glass powder generated from the microcracks. In particular, in the case of a high-definition FPD, since it is necessary to form a dense electric circuit, the electric circuit is likely to cause disconnection or the like even with a small amount of minute glass powder, and it is likely to cause a manufacturing failure of the FPD.

  Therefore, Patent Document 1 discloses a method for inspecting the end face of a glass plate in consideration of glass powder that may be generated from minute cracks. Specifically, in this document, by sliding while pressing the tip of the resin tube against the end face of the glass plate, the end face of the glass plate is rubbed to scrape off the particles on the end face, and the scraped particles are resinated. It is disclosed that suction is performed from the tip of a tube and the number is counted by a particle counter.

JP 2010-230646 A

  In the end surface inspection method disclosed in Patent Document 1, since minute foreign matter in the air is also sucked together from the tip of the resin tube, the minute foreign matter is also counted as glass powder, and the accuracy of the end face inspection of the glass plate is very poor. There is a problem of becoming. As a result, even a glass plate that has cleared the end face inspection disclosed in Patent Document 1 may still cause manufacturing failure of FPD due to glass powder generated from microcracks. Therefore, it is desired to provide a glass plate with very little glass powder generated from the end face more reliably.

  This invention makes it a technical subject to provide more reliably the glass plate which has very few glass powder generated from an end surface by improving the precision of the end surface inspection of a glass plate.

  The present invention invented in order to solve the above problems is a glass plate end surface inspection method having a polished surface on an end surface of a glass plate, a first observation step of observing a specific region of the polished surface, and a glass plate External stimulus applying step for applying an external stimulus to the polished surface of the substrate, a cleaning step for cleaning the specific region, a second observation step for observing the specific region again, an observation result of the first observation step, and a second observation step And an evaluation step of counting the number of minute recesses newly formed in the specific region after the first observation step, in this order. According to such a configuration, even when there is a microcrack in a specific region provided on the polished surface of the glass plate, the microcrack grows forcibly by an external stimulus applied in the external stimulus application step, It tends to appear as glass powder. And since the glass powder generated in this way is removed by cleaning from a specific region of the polishing surface in the cleaning process, in the portion corresponding to the glass powder generated from the micro cracks in the specific region of the polishing surface, A minute recess is formed. Therefore, in the evaluation process, the observation result of the specific area of the polished surface in the first observation process before the external stimulus applying process and the cleaning process, and the second observation process after the external stimulus applying process and the cleaning process Comparing the observation results of the specific area of the polished surface, the number of minute recesses newly formed in the specific area after the first observation step can be accurately counted. As described above, the number of the minute recesses accurately reflects the number of glass powders generated from the microcracks. Therefore, the number of the microrecesses may be generated from the microcracks without directly counting the number of glass powders. It is possible to inspect the end face of the glass plate in consideration of the glass powder with a certain amount.

  In the above configuration, it is preferable that the cleaning step also serves as an external stimulus applying step, and the specific region is cleaned while applying the external stimulus. In this way, the external stimulus applying process is also performed simultaneously in the cleaning process, so that the inspection efficiency is improved as compared with the case where both these processes are performed individually.

  In the above configuration, the cleaning process that also serves as the external stimulus applying process may be ultrasonic cleaning. In this way, the specific region of the polishing surface is cleaned while being given an external stimulus by the vibration accompanying the ultrasonic cleaning.

  In the above configuration, the cleaning process that also serves as the external stimulus applying process may be chemical cleaning. By doing so, a specific region of the polishing surface is cleaned while being given external stimulus by a chemical reaction accompanying chemical cleaning. Here, the chemical cleaning may be acid cleaning or alkali cleaning. Further, chemical cleaning and ultrasonic cleaning may be used in combination by performing ultrasonic cleaning using a chemical cleaning solution.

  In the above configuration, in the first observation step, the specific region is magnified to obtain the first magnified image, and in the second observation step, the specific region is magnified to obtain the second magnified image, and the evaluation step Thus, it is preferable to compare the first enlarged image and the second enlarged image. In this way, accurate information on the specific area of the polished surface can be acquired as an image, so that the counting accuracy of the number of minute defects in the evaluation process can be increased.

  In the above-described configuration, it is preferable to form a marking portion that serves as a setting reference for the specific region on the polished surface. In this way, it is possible to reduce as much as possible the setting deviation of the specific region between the first observation process and the second observation process. Therefore, the accuracy of counting the number of micro defects in the evaluation process is also improved.

  The present invention created in order to solve the above-mentioned problems is a method for manufacturing a glass plate, in which a glass plate is cut out from each of a plurality of original glass plates to obtain a plurality of glass plates, and a plurality of steps A polishing step for polishing the end surface of the glass plate, and a sampling inspection step for extracting the inspection glass plate from the plurality of glass plates, and inspecting the inspection glass plate by the end surface inspection method for the glass plate, It is characterized by having. Here, the inspection glass plate includes a case where the glass plate obtained in the cutting step is used as it is and a case where a small piece obtained by cutting the glass plate is used. According to such a configuration, the accuracy of the end surface inspection of the glass plate can be improved for the reasons described above, and therefore, a glass plate with very little glass powder generated from the end surface can be provided.

The present invention devised to solve the above problems is a glass plate having a polished surface on its end surface, and when the polished surface is ultrasonically cleaned for 15 minutes using an alkali cleaning solution at a temperature of 40 ° C. The surface is characterized in that the density of minute recesses newly formed by ultrasonic cleaning and corresponding to glass powder is 0 to 1000 / mm ² . According to such a structure, it becomes a glass plate with very few glass powder generated from an end surface irrespective of progress of time. That is, for example, even if an external stimulus is received in a cleaning process included in the FPD manufacturing process, glass powder generated from the end face can be reduced as much as possible in the subsequent FPD manufacturing process.

  According to the present invention as described above, it is possible to improve the accuracy of the end face inspection of the glass plate. Therefore, it becomes possible to provide a glass plate with very little glass powder generated from the end face more reliably.

It is a top view for demonstrating a cutting process. It is a top view for demonstrating a grinding | polishing process. It is a side view which shows the grinding | polishing tool used at a grinding | polishing process. It is a perspective view which shows the glass plate for a test | inspection. It is a longitudinal cross-sectional view for demonstrating a washing | cleaning process. It is a figure which shows an example of the 1st enlarged image of the specific area | region obtained by a 1st observation process when a grinding | polishing surface is a rough surface. It is a figure which shows an example of the 2nd enlarged image of the specific area | region obtained by a 2nd observation process when a grinding | polishing surface is a rough surface. It is a figure which shows an example of the 1st enlarged image of the specific area | region obtained by a 1st observation process when a grinding | polishing surface is a smooth surface. It is a figure which shows an example of the 2nd enlarged image of the specific area | region obtained by a 2nd observation process, when a grinding | polishing surface is a smooth surface. It is a figure which shows an example of the 1st enlarged image of the specific area | region obtained by a 1st observation process when a grinding | polishing surface is a rough surface. It is a figure which shows an example of the 2nd enlarged image of the specific area | region obtained by a 2nd observation process when a grinding | polishing surface is a rough surface. It is a figure which shows an example of the 1st enlarged image of the specific area | region obtained by a 1st observation process when a grinding | polishing surface is a smooth surface. It is a figure which shows an example of the 2nd enlarged image of the specific area | region obtained by a 2nd observation process, when a grinding | polishing surface is a smooth surface.

  Hereinafter, the embodiment of the manufacturing method of the glass plate concerning the present invention is described. In the following, in the course of explaining the glass plate manufacturing method, the glass plate end surface inspection method will also be described. However, the glass plate end surface inspection method may be carried out independently from the glass plate manufacturing method. it can.

  The glass plate manufacturing method according to the present embodiment includes a cutting process, a polishing process, and a sampling inspection process.

  In the cutting process, as shown in FIG. 1, by cutting the original glass plate M along the planned cutting line CL, a plurality of (four in the illustrated example) glass plates G are formed from one original glass plate M. So-called multi-sided acquisition is performed. In the cutting step, the peripheral edge of the original glass plate M may be trimmed to obtain one glass plate G from one original glass plate M.

  In the present embodiment, the original glass plate M is formed by the overflow downdraw method, but is not limited thereto. For example, it may be formed by another downdraw method such as a slot downdraw method or a redraw method, or a float method.

  As a method for cutting the original glass plate M, so-called bending stress cleaving is used in which a scribe line is formed on the planned cutting line CL of the original glass plate M, and then the original glass plate M is folded along the scribe line. In addition, as a cutting method of the original glass plate M, thermal stress cleaving (for example, laser cleaving), fusing (for example, laser fusing) or the like may be used.

  In the polishing step, as shown in FIG. 2, the end surfaces (cut surfaces) of the plurality of glass plates G cut in the cutting step are polished. In the present invention, the polishing includes grinding. Specifically, first, the first polishing tool 2 (for example, a grindstone) is run on the upstream stage 1 along the two opposing sides of the glass plate G, and the end faces G1 of the two opposing sides are polished. Next, after the glass plate G is turned 90 degrees on the turning stage 3, the second polishing tool 5 (for example, along the remaining two opposite sides of the turned glass plate G on the downstream stage 4). The grindstone is run, and the remaining two end faces G2 are polished. Thereby, each end surface G1, G2 of the four sides of the glass plate G is polished. The polishing procedure shown in FIG. 2 is merely an example, and as long as the end faces G1 and G2 on the four sides of the glass plate G are polished, the moving procedure of the glass plate G and the polishing tools 2 and 5, The number of is not particularly limited. For example, the end surface of one side of the glass plate G may be polished a plurality of times with a polishing tool having different eye roughness and binder, and finish polishing may be performed after the rough polishing.

  As shown in FIG. 3, the first polishing tool 2 is provided on a cylindrical first processing surface 21 extending in the thickness direction of the glass plate G and both ends of the first processing surface 21. And a pair of conical second processing surfaces 22 having inclinations opposite to each other in the thickness direction. Therefore, the end face G1 of the glass plate G polished by the first polishing tool 2 is polished into a shape following the first processed surface 21 and the second processed surface 22 of the first polishing tool 2. That is, the end surface G1 of the glass plate G polished by the first polishing tool 2 is provided at both ends of the first polishing surface G1a extending in the plate thickness direction and the first polishing surface G1a, and is mutually opposite to the plate thickness direction. And a pair of second polishing surfaces G1b having opposite inclinations. Although illustration is omitted, since the second polishing tool 5 has the same configuration as the first polishing tool 2, the end face G2 of the glass plate G polished by the second polishing tool 5 is also polished by the first polishing tool 2. The glass plate G has the same shape as the end face G1. Here, in FIG. 3, the part X which attached | subjected cross hatching has shown the glass part removed by grinding | polishing.

  In addition, although the case where the 1st grinding | polishing surface G1a and the 2nd grinding | polishing surface G1b of the glass plate G were formed simultaneously with the one 1st grinding | polishing tool 2 was demonstrated, these grinding | polishing surfaces G1a and G1b were used with separate grinding | polishing tools. You may form separately. The same applies to the second polishing tool 5. Moreover, the cross-sectional shape of the end surfaces G1 and G2 of the polished glass plate G is not particularly limited, and may be a semicircular shape, an arc shape, a semielliptical shape, a shape constituted by a plurality of straight lines, or the like. . Alternatively, the cross-sectional shape of the end faces G1, G2 of the glass plate G may be a shape obtained by changing the cross-sectional shape of the second polishing surface G1b to an arc shape in the cross-sectional shape shown in FIG.

  The feed rate of the polishing tools 2 and 5 is preferably 1 to 15 m / min, more preferably 1 to 10 m / min. That is, in general polishing of a glass plate, the feed rate of the polishing tool exceeds 15 m / min and is 60 m / min or less. Therefore, the preferable range of the feed rate of the polishing tools 2 and 5 is generally Slow compared to typical feed rate. Note that the feed rate of the polishing tools 2 and 5 means the relative speed of the polishing tools 2 and 5 with respect to the glass plate G when polishing while moving the glass plate G.

  In the sampling inspection process, one or a plurality of glass plates G are extracted as inspection glass plates S (see FIG. 4) from the plurality of glass plates G polished in the polishing step (in the same lot). The end face inspection is performed on the inspection glass plate S. The sampling may be performed at predetermined time intervals. Alternatively, it may be performed every time manufacturing conditions such as polishing conditions are changed. Further, the end face inspection of the inspection glass plate S corresponds to the end face inspection method of the glass plate.

  The end face inspection includes a first observation process, a cleaning process, a second observation process, and an evaluation process.

  In the first observation step, as shown in FIG. 4, the polished surface S1a (corresponding to the first polished surface of the glass plate G) and S1b (second polished glass plate G) formed on the end surface S1 of the inspection glass plate S. The specific region R corresponding to the surface is enlarged and observed with a scanning electron microscope (SEM), and a first enlarged image of the specific region R is acquired.

  The glass plate G for inspection may use the extracted glass plate G as it is, but in the present embodiment, the inspection glass plate S is composed of small pieces that are further cut to include the polished surface.

  In the present embodiment, the specific region R is provided on the first polishing surface S1a. This is because the first polishing surface S1a may be in contact with other members than the second polishing surface S1b, and it is considered that the risk of glass powder generation is high. The specific region R may be provided not on the first polishing surface S1a but on the second polishing surface S1b, or on both the first polishing surface S1a and the second polishing surface S1b.

  It is preferable to form a marking portion (not shown) serving as a setting reference for the specific region R on the first polishing surface S1a where the specific region R is provided. The marking part is formed, for example, by forming a concave groove (scratch) on the first polishing surface S1a or by forming a film (such as a sputtered film). In addition, although a marking part is not limited to what was formed by these methods, what was formed by the method which is hard to be removed by a washing | cleaning process is preferable. The marking part is formed along the rectangular outer edge of the specific region R, for example.

  In the cleaning process, as shown in FIG. 5, the specific region R provided on the polishing surfaces S1a and S1b of the inspection glass plate S is cleaned while being given an external stimulus. The portion to be cleaned in the cleaning step may be only the specific region R or a portion including the specific region R. Although the illustrated example is merely an example of the cleaning mode, in detail, the inspection glass plate S includes a specific region R provided on the first polishing surface S1a in a state of being supported suspended by the support member 6. A portion (about the lower half of the inspection glass plate S in the illustrated example) is immersed in the cleaning liquid 8 in the container 7. At this time, it is preferable that the first polishing surface S1a provided with the specific region R is not in contact with the container 7 in order to increase the contact efficiency with the cleaning liquid 8. The container 7 is disposed in an ultrasonic cleaning machine 10 in which water 9 as an ultrasonic transmission medium is stored, and the specific region R of the inspection glass plate S is moved by ultrasonic vibration propagated to the cleaning liquid 8 through the water 9. The containing part is ultrasonically cleaned.

  The ultrasonic cleaning time is preferably 1 to 60 minutes, and more preferably 3 to 30 minutes. The temperature for ultrasonic cleaning is preferably 15 to 80 ° C, and more preferably 25 to 60 ° C. The frequency of ultrasonic cleaning is preferably 10 to 1000 kHz, and more preferably 20 to 200 kHz.

The cleaning liquid 8 includes pure water mixed with an alkaline detergent (for example, (CH ₃ ) ₄ NOH, NaOH, KOH, etc.), or pure water with an acid detergent (for example, HCl, HNO ₃ , H ₂ SO _4, etc.). It is preferable to chemically clean the glass plate S for inspection using a mixture of the above. However, when ultrasonic cleaning is used, an external stimulus is applied to the polished surfaces S1a and S1b of the glass plate S for inspection by vibration during the ultrasonic cleaning, so that an external stimulus due to a chemical reaction is not further applied. May be. In other words, when ultrasonic cleaning is used, the cleaning liquid 8 may be pure water or the like that does not give an external stimulus due to a chemical reaction to the polishing surfaces S1a and S1b of the inspection glass plate S.

  Note that the cleaning process may use high-pressure cleaning in which a specific region R of the inspection glass plate S or a portion including the specific region R is sprayed and cleaned with a high-pressure liquid such as high-pressure water. Also in this case, the polished surfaces S1a and S1b of the inspection glass plate S are cleaned while being externally stimulated by the high-pressure liquid.

  In the second observation step, the specific region R of the inspection glass plate S observed in the first observation step is enlarged and observed again with the SEM, and a second enlarged image of the specific region R is acquired. In addition, it is preferable that the enlarged observation by SEM in a 2nd observation process is the same conditions (acceleration voltage, observation magnification, etc.) as the enlarged observation by SEM in a 1st observation process.

  In the evaluation process, the first enlarged image, which is the observation result of the first observation process, is compared with the second enlarged image, which is the observation result of the second observation process, and newly in the specific region R after the first observation process. Count the number of micro-recesses formed.

  In the present embodiment, the concave portion having a size corresponding to the glass powder in a plan view (view from the perpendicular direction of the specific region R) is determined as a fine concave portion and counted. The criterion for determining the minute recess may be set as appropriate according to the required quality. For example, a concave portion having a length of about 0.1 to 10 μm in plan view may be determined as a fine concave portion. Or you may determine the recessed part about 0.1-5 micrometers in planar view as a micro recessed part. The number of minute recesses may be automatically counted by image processing or the like, or may be manually counted by an operator.

  As for the size of the specific region R, the number of minute recesses on the entire first polishing surface G1a (and / or second polishing surface G1b) of the glass plate G can be predicted to some extent from the number of minute recesses counted in the evaluation process. Any size is acceptable. Therefore, the specific region R is preferably set to a rectangular region having a side of 10 to 500 μm.

  The magnification for magnified observation of the specific region R is related to the detection accuracy of the minute recesses. Therefore, the magnification for magnification observation is preferably 1000 to 50000 times, and more preferably 5000 to 50000 times.

  Here, the first enlarged image and the second enlarged image are illustrated in FIGS. FIGS. 6 and 7, FIGS. 8 and 9, FIGS. 10 and 11, and FIGS. 12 and 13 are observation results of the same specific region. Among these, in FIG. 6 and FIG. 7 and FIG. 10 and FIG. 11, the first polishing surface S1a provided with the specific region R in order to artificially increase the possibility that glass powder is generated over time from the minute crack. The surface roughness is increased.

  In the case where the polished surface provided with the specific region R is a rough surface, when the magnification of magnification observation is increased (10,000 times), minute recesses that are not confirmed in the first enlarged image shown in FIG. (A portion surrounded by a circle C1 in FIG. 7). On the other hand, when the polished surface provided with the specific region R is a smooth surface, a minute concave portion that was not confirmed in the first enlarged image shown in FIG. 8 was newly confirmed in the second enlarged image shown in FIG. It never happened.

  Further, when the magnification of magnification observation is lowered (1000 times), when the polished surface provided with the specific region R is a rough surface, a minute recess that is not confirmed in the first enlarged image shown in FIG. In the second enlarged image shown in FIG. 11, it was confirmed at many new locations (portion surrounded by a circle C2 in FIG. 11). On the other hand, when the polished surface provided with the specific region R is a smooth surface, a minute concave portion that was not confirmed in the first enlarged image shown in FIG. 12 was newly confirmed in the second enlarged image shown in FIG. It never happened.

  From these results, it can be confirmed that the number of minute recesses tends to increase in the glass plate for inspection in which glass powder is likely to be generated from minute cracks. Therefore, according to the end face inspection according to the present embodiment, even if the number of glass powders is not directly counted, by counting the number of minute recesses in the evaluation process, a large amount of glass powder may be generated in the future. Whether it is a certain glass plate can be judged correctly. Moreover, the size of the glass powder generated from the size of the minute recesses can be predicted to some extent.

In the evaluation step, the number of counted micro-recesses (preferably, (the number of micro-recesses) / (density of the micro-recesses)) is a predetermined judgment value (for example, 1000 / mm ² , If it is preferably 500 pieces / mm ² ) or less, the glass plate G contained in the same lot as the glass plate for inspection S can be evaluated as being less likely to generate glass powder in the future. Therefore, in this case, the quality of the glass plate G included in the same lot is determined as “accepted” and shipped as a product as it is.

The glass plate G thus determined to be acceptable is newly formed by ultrasonic cleaning on the polished surface when the polished surface is ultrasonically cleaned for 15 minutes using an alkaline cleaning liquid at a temperature of 40 ° C., and The density of the minute recesses having a size corresponding to the glass powder (the number of the minute recesses / the area of the polished surface) is 0 to 1000 / mm ² (preferably 0 to 500 / mm ² ). With such a glass plate G, defective electrode formation due to glass powder is unlikely to occur in each film forming process even if cleaning, etching, and the like are repeatedly performed in the FPD manufacturing process. Therefore, it can be suitably used as a glass substrate for high definition FPD such as IGZO.

  Here, evaluation of the above characteristics of the glass plate G determined to be acceptable is performed as follows. That is, the measurement of the density of the minute recesses is performed by the same method as the end face inspection. At this time, Quanta250 FEG manufactured by FEI is used for observation of the minute recesses (SEM observation). Further, the magnification is 10,000 times, and the specific region R is a rectangular region having a side of 10 μm. For ultrasonic cleaning, Ultrason VS-30 manufactured by VELVO-CLEAR is used, and the frequency of the ultrasonic wave is 35 kHz. As the alkaline cleaning liquid, an aqueous solution containing 0.2% by mass of KOH is used. In the determination of a minute recess, a recess having a length of about 0.1 to 5 μm in plan view is determined as a minute recess.

  On the other hand, in the evaluation process, if the counted number of minute recesses exceeds the determination value, the quality of the glass plate G included in the same lot as the inspection glass plate S is determined as “fail”, for example, in the polishing step Change the polishing conditions (feeding speed of polishing tool and type of polishing tool). Then, in the evaluation process, the end face inspection and the change of the polishing conditions are repeated until the number of counted minute recesses is equal to or less than the determination value. Here, if the feed rate of the polishing tools 2 and 5 is set in the range of 1 to 15 m / min as described above, it becomes easy to manufacture the glass plate G whose quality satisfies the acceptance criteria.

  Here, the end face inspection can be used for selecting a polishing tool if the point of focus is changed. That is, the polishing tool used when the number of minute recesses in the evaluation process is equal to or less than the determination value is “pass”, and the polishing tool used when the number of minute recesses exceeds the determination value in the evaluation process is By selecting “Fail”, the polishing tool can be selected.

  In addition, this invention is not limited to the structure of said embodiment, It is not limited to an above-described effect. The present invention can be variously modified without departing from the gist of the present invention.

  In the above embodiment, the cleaning process of cleaning the polished surface of the glass plate while applying an external stimulus to the polished surface of the glass plate, that is, the cleaning process that also serves as the external stimulus applying process has been described. You may perform separately the external stimulus provision process which provides an external stimulus, and the washing | cleaning process which wash | cleans the grinding | polishing surface of a glass plate. In this case, in the external stimulus applying step, an external stimulus may be applied to the polished surface of the glass plate by moving the contact made of a resin material or the like against the polished surface of the glass plate. Moreover, you may give external irritation | stimulation to the grinding | polishing surface of a glass plate by injecting high pressure gas and microparticles | fine-particles on the grinding | polishing surface of a glass plate.

  In the above embodiment, the case where the specific region is observed using the SEM has been described. However, the specific region may be observed using an optical microscope, a laser microscope, an X-ray CT, or the like.

DESCRIPTION OF SYMBOLS 1 Upstream stage 2 1st grinding | polishing tool 3 Turning stage 4 Downstream stage 5 2nd grinding | polishing tool 8 Cleaning fluid 10 Ultrasonic cleaner G Glass plate G1, G2 End surface G1a First grinding surface G1b Second grinding surface M Original glass plate R Specific area S Inspection glass plate S1 End surface S1a First polishing surface S1b Second polishing surface

Claims (8)

An end surface inspection method for a glass plate having a polished surface on an end surface,
A first observation step of observing a specific region of the polished surface;
Providing an external stimulus to the specific region;
A cleaning step of cleaning the specific area;
A second observation step of observing the specific area again;
An evaluation step of comparing the observation result of the first observation step and the observation result of the second observation step, and counting the number of minute recesses newly formed in the specific region after the first observation step; A method for inspecting an end face of a glass plate, which is provided in this order.   The method for inspecting an end face of a glass plate according to claim 1, wherein the cleaning step also serves as the external stimulus applying step, and the specific region is cleaned while being applied with the external stimulus.   3. The method for inspecting an end face of a glass plate according to claim 2, wherein the cleaning step that also serves as the external stimulus applying step is ultrasonic cleaning.   The method for inspecting an end face of a glass plate according to claim 2 or 3, wherein the cleaning step serving also as the external stimulus applying step is chemical cleaning.   In the first observation step, the specific region is magnified to obtain a first magnified image, and in the second observation step, the specific region is magnified to obtain a second magnified image, and the evaluation step 5. The method for inspecting an end face of a glass plate according to any one of claims 1 to 4, wherein the first enlarged image and the second enlarged image are compared.   The glass plate end face inspection method according to claim 1, wherein a marking portion serving as a setting reference for the specific area is formed on the polished surface. Cutting a glass plate from each of a plurality of original glass plates, a cutting step of acquiring a plurality of glass plates,
A polishing step of polishing an end face of the plurality of glass plates;
A sampling inspection step of extracting the inspection glass plate from the plurality of glass plates, and inspecting the inspection glass plate by the edge inspection method of the glass plate according to any one of claims 1 to 6, The manufacturing method of the glass plate characterized by the above-mentioned. A glass plate having a polished surface on an end surface,
When the polished surface is ultrasonically cleaned using an alkaline cleaning liquid at a temperature of 40 ° C. for 15 minutes, a minute concave portion that is newly formed on the polished surface by the ultrasonic cleaning and has a size corresponding to glass powder. The glass plate characterized by having a density of 0 to 1000 pieces / mm ² .