JP2005156539A - Apparatus for detecting breakage of edge part of glass substrate and its method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect breakages which easily occur at edge parts of glass substrates for flat-panel displays while the glass substrates are moving through the use of a minimal number of optical sensors. <P>SOLUTION: This breakage detecting apparatus consists of two sensors for recognizing the glass substrates and generating signals while the glass substrates are passing, and of a control unit electrically connected to the two sensors for receiving the signals each from the two sensors, reading the signals each received from the two sensors while each glass substrate passes above or below the two sensors, determining the time required for the glass substrate to completely pass each sensor, or counting the number of pulses on the basis of the signals each received from the two sensors while each glass substrate passes above or below the two sensors, and comparing the determined time or the counted number of pulses with a predetermined reference value to determine the presence or absence of breakage of the glass substrate. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  More particularly, the present invention relates to an apparatus and a method for detecting a breakage of an edge portion of a glass substrate. The present invention relates to an apparatus and a method for detecting using a minimum optical sensor.

  In general, a glass substrate is an indispensable component in manufacturing a flat panel display device such as a liquid crystal display device (LCD) or a plasma panel display (PDP). In order to manufacture a flat panel display device such as a liquid crystal display device, processing steps such as a cleaning step, a film coating step, and a development step are repeatedly performed on a glass substrate. It consists of complex equipment to perform the processing steps. Recently, in-line production systems and cluster production systems have been developed and used as automated production systems for automatically performing these processing steps on glass substrates. Transfer and processing of the glass substrate is extremely important in the processing stage.

  A production system of a liquid crystal display device or a plasma panel display is composed of a plurality of complicated devices in order to perform various processing steps repeated as described above, and a glass substrate is formed between such a plurality of devices. Since it must move and is exposed to a plurality of repeated processing steps, it is vulnerable to breakage, especially the edge portion of the glass substrate is more susceptible to breakage. For this reason, in a production line of a flat panel display device, after one step is completed and before the glass substrate is put into the next step, the glass substrate is damaged due to a process failure or generated during transfer, particularly It is necessary to detect whether or not the glass substrate is abnormal by detecting the breakage of the four edge portions. If the broken glass substrate is thrown into the process module of an automation system such as a cluster production system without confirming such breakage of the glass substrate, not only the process failure but also the unexpected system malfunction And cause a failure.

  Therefore, in the technical field to which the present invention belongs, in order to minimize the loss of system equipment due to the smooth process flow and the glass pieces of the broken glass substrate, the presence or absence of glass substrate breakage is input to the process module. We go ahead and take measures such as issuing an alarm if there is an abnormality. That is, in equipment that performs long-time process processing, such as a production system of a flat panel display device, the glass substrate may be damaged in the transfer process or in each complicated processing process. When such a glass substrate is damaged, Since the fine glass powder may cause a process failure and a loss of system equipment, the confirmation process of whether or not the glass substrate is broken must be performed before being put into each process module.

  However, conventionally, in a production system of a flat panel display device, a method for detecting breakage of a glass substrate is a method of detecting the presence or absence of breakage in a state where the glass substrate is stopped before the glass substrate is put into each processing step. Therefore, a separate measurement time is required, which causes a problem that the flow between the processes is not smooth. In addition, the conventional method requires a sensor corresponding to each edge of the glass substrate in addition to the problem that the presence or absence of breakage must be confirmed while the glass substrate is stopped before being put into each process module. Therefore, there is a problem that many sensors are required and measurement is possible only within a limited range. In particular, a cluster production system for a flat panel display device includes a load lock for loading a glass substrate and a facet capable of supporting a plurality of process modules (for example, first to sixth process modules). In such a cluster production system, the glass substrate is loaded with the presence or absence of breakage of each edge of the glass substrate before the glass substrate is put into each process module. It is detected by an optical sensor provided at the bottom of the table. However, in the conventional detection method, as shown in FIG. 7, in order to detect the breakage of the edge portion of the glass substrate, the glass substrate must be stopped in the transport chamber. Because the number of optical sensors increases in proportion to the number of process modules (for example, a cluster production system that supports six process modules requires 14 sensors), a large number of optical sensors are required. There was a problem.

  The present invention has been made in view of the above-described problems, and a minimal optical sensor is used in a state in which the glass substrate moves to prevent breakage that easily occurs at the edge portion of the glass substrate that moves on the production line of the flat panel display device. It is an object of the present invention to provide an apparatus and a method for detecting by using.

  Moreover, since the presence or absence of breakage of the glass substrate can be detected when the glass substrate moves between the respective process modules, there is no need for a separate measurement time, and all the edges of the glass substrate can be detected with only two to three sensors. It is another object to provide an apparatus and method capable of detecting breakage.

  In order to achieve the above object, the glass substrate edge portion breakage detection apparatus according to the present invention is provided at the lower or upper part of the position where the glass substrate should move, and recognizes the glass substrate while the glass substrate passes. And at least two sensors for generating a signal and electrically connected to the at least two sensors to receive signals from the at least two sensors, and a glass substrate passes above or below the at least two sensors. While reading the signals received from the at least two respective sensors to determine the respective time required for the glass substrate to completely pass through the respective sensors, or the glass substrate is adapted to the at least two sensors. Receive from the at least two respective sensors while passing through the top or bottom of the The number of each pulse is counted from the detected signal, and each such determined time or the number of each counted pulse is compared with a predetermined reference value to determine whether the glass substrate is broken or not. And a controller for performing the operation.

  In addition, the controller compares the determined time or the number of counted pulses with a predetermined reference value, and the time or the number of pulses is more than the predetermined reference value. When it is small, it is determined that the glass substrate is damaged, and when it is the same, it is determined that the glass substrate is not damaged.

  The at least two sensors are provided with a pair of left and right at the lower or upper part of the position where the left and right edge portions of the glass substrate should move, and recognize the glass substrate and generate a signal while the glass substrate passes. And / or a reference sensor located between these edge sensors. Such a reference sensor generates a synchronization signal with respect to a signal generated from each edge sensor.

  The sensor is an optical sensor, and it is preferable to use a transmissive sensor rather than a reflective sensor. In general, the reflective sensor reacts sensitively according to the reflection angle, and a large difference in sensitivity occurs due to the deflection of the glass substrate. Therefore, it is preferable to use a transmission type sensor that is easy to detect in consideration of the characteristics of the glass substrate whose peripheral portion is greatly bent.

  As the optical sensor, those having excellent response characteristics are used, and those having a sensor response time of 200 μs or less are particularly preferable.

  Further, as the controller, a dedicated microprocessor is used, and it is preferable that the scan time is short in order to detect breakage of the edge portion of the moving glass substrate.

  As described above, the controller determines a time during which an optical sensor such as an edge sensor or a reference sensor is turned on, or the number of pulses, and compares it with a predetermined reference value. Determine whether the glass substrate is damaged.

  The resolution for detecting whether the moving glass substrate is broken is determined by the sensor response time, the controller scan time, and the glass substrate moving speed. The glass substrate moving speed is 1000 mm / sec. When the control sampling time considering the time is 500 μs, the minimum resolution is 0.5 mm / pulse. In this case, the moving glass substrate is measured for breakage with an accuracy of 0.5 mm. In addition, since a smaller breakage site can be detected as the minimum detection interval is shortened, it is preferable to set it as small as the sensor and the instrument structure allow.

  In addition, the edge detecting device for a glass substrate according to the present invention further includes a main controller electrically connected to a controller through an input / output interface. The main controller is a flat panel display device. This is a device that controls the entire in-line production system or cluster production system. When the controller of the present invention determines that a glass substrate is broken, the alarm device is controlled to generate an alarm signal or the glass substrate is transferred. The movement of the glass substrate is stopped by controlling the transfer device.

  Note that the method for detecting breakage of the edge portion of the glass substrate according to the present invention includes at least two sensors provided at the lower part or the upper part of the position where the glass substrate should move, while the glass substrate passes through the glass substrate. Recognizing and generating a signal; and a controller electrically connected to the at least two sensors and receiving signals from the at least two sensors, wherein the glass substrate is above or below the at least two sensors. The signals received from the at least two respective sensors during the passage of time to determine the respective time required for the glass substrate to completely pass through the respective sensors, or From the at least two respective sensors while passing over the top or bottom of the two sensors A step of counting the number of each pulse from the received signal, and comparing the respective determined time or the number of each counted pulse with a predetermined reference value by the controller; Determining whether or not there is damage.

  The step of determining whether or not the glass substrate is broken includes comparing each of the determined times or the number of counted pulses with a predetermined reference value, and determining the time or the number of pulses in advance. If it is smaller than the reference value, it is determined that the glass substrate is damaged, and if it is the same, it is determined that the glass substrate is not damaged.

  According to the present invention, breakage that is likely to occur at the edge portion of the glass substrate moving on the production line of the flat panel display device can be detected using a minimum of optical sensors in a state where the glass substrate moves, When the glass substrate moves between each process, it can detect whether or not the glass substrate is broken, so there is no need for a separate measurement time, and only 2 or 3 sensors can damage all edges of the glass substrate. Can be detected.

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

  FIG. 1 is a schematic configuration diagram illustrating a breakage detection device for an edge portion of a glass substrate according to the present invention. This apparatus is provided at the lower part of the position where the left and right edge portions of the glass substrate 10 should move, and the sensor 20 recognizes the glass substrate and generates a signal while the glass substrate passes, The reflection plate 22 is positioned opposite to the sensor 20 and a controller 30 that is electrically connected to the sensor 20 and receives a signal from each sensor 20.

  The controller 30 reads a signal received from each sensor 20 while the glass substrate 10 passes over the sensor 20, and is required for the glass substrate 10 to completely pass each sensor 20. Each time is determined or the number of each pulse is counted from the signal received from each sensor 20 while the glass substrate 10 passes over the sensor 20.

  The controller 30 compares the determined time or the number of counted pulses with a predetermined reference value to determine whether the glass substrate 10 is broken. A specific process for determining whether or not the glass substrate 10 is broken by the controller 30 will be described later with reference to FIGS.

  Further, the detection device may include a main controller 40 electrically connected to the controller 30 through an external device input / output interface. The main controller 40 may damage the glass substrate 10 with the controller 30. When the determination is made, an alarm device (not shown) is controlled to generate an alarm signal, or a transfer device (not shown) for transferring the glass substrate 10 is controlled to stop the movement of the glass substrate 10.

  FIG. 2 is a plan view showing the positional relationship between the normal glass substrate and these sensors when the normal glass substrate 10 passes through the edge sensors 20a, 20b and the reference sensor 20c located in the lower part in the detection apparatus. It is.

2 (a), 2 (b), and 2 (c) show waveforms of signals detected from the edge sensors 20a and 20b and the reference sensor 20c located below when a normal glass substrate moves. Shown against the time axis. From the graph (a) in FIG. 2, from the time t ₀ when the tip of the normal glass substrate 10 passes the edge sensor 20 a to the time t ₃ when the rear end of the glass substrate 10 passes the edge sensor 20 a, The edge sensor 20a recognizes the glass substrate 10 and generates a signal of a certain magnitude, and this signal waveform is generated by the reference sensor 20c located between the two edge sensors 20a and 20b (c) in FIG. This is the same waveform as the sync signal waveform shown in FIG. Further, from the graph (b) in FIG. 2, the time t ₃ when the rear end of the glass substrate 10 passes the edge sensor 20 b from the time t ₀ when the front end of the normal glass substrate 10 passes the edge sensor 20 b. The edge sensor 20b recognizes the glass substrate 10 and generates a signal of a certain magnitude, and this signal waveform is generated by the reference sensor 20c located between the two edge sensors 20a and 20b in FIG. It is the same waveform as the synchronization signal waveform shown in c). When the signal waveforms from the two edge sensors 20a and 20b are the same as the synchronization signal waveform generated by the reference sensor 20c, it is necessary while the glass substrate 10 completely passes through the two edge sensors 20a and 20b. The time or the number of generated pulses coincides with a predetermined reference value, and as a result, the controller determines that the glass substrate is not broken.

  FIG. 3 is a plan view showing the positional relationship between the broken glass substrate and these sensors when the broken glass substrate 10 passes through the edge sensors 20a, 20b and the reference sensor 20c located in the lower part in the detection device. It is.

3 (a), 3 (b), and 3 (c) show waveforms of signals detected from the edge sensors 20a and 20b and the reference sensor 20c located below when the broken glass substrate moves. Shown against the time axis. Referring to the graph (a) in FIG. 3, the time t ₃ when the rear end of the damaged glass substrate 10 passes the edge sensor 20a from the time t ₁ when the tip of the damaged glass substrate 10 passes the edge sensor 20a. Until now, the edge sensor 20a recognizes the glass substrate 10 and generates a signal of a certain magnitude, and this signal waveform is generated by the reference sensor 20c located between the two edge sensors 20a and 20b in FIG. Unlike the synchronous signal waveform as shown in c), no signal is generated in the period from t _{0 to} t ₁ . Such a section between t _{0 and} t ₁ is a section in which it is detected that the edge of the tip of the glass substrate passing through the edge sensor 20a is broken, and the broken glass substrate 10 completely passes through the edge sensor 20a. In the meantime, the required time or the number of generated pulses becomes smaller than a predetermined reference value, and as a result, the controller determines that the glass substrate is broken.

Looking at the graph of (b) in FIG. 3, when the rear end portion of the glass substrate 10 in which the distal end portion of the broken glass substrate 10 is broken from time t ₀ which has passed through the edge sensor 20b passes the edge sensor 20b until t _2, the edge sensor 20b recognizes the glass substrate 10 by generating a predetermined signal magnitude, the signal waveform, FIG. 3 generated by two edges sensor 20a, the reference sensor 20c located between 20b Unlike the synchronous signal waveform shown in (c), no signal is generated in the period from t _{2 to} t ₃ . Such a t ₂ to t ₃ section is a section in which it is detected that the edge of the rear end of the glass substrate passing through the edge sensor 20b is broken, and the broken glass substrate 10 completely removes the edge sensor 20b. While passing, the required time or the number of generated pulses becomes smaller than a predetermined reference value, and as a result, the controller determines that the glass substrate is broken.

  Hereinafter, a method for detecting breakage of the edge portion of the glass substrate according to the present invention will be described with reference to FIG.

  First, the glass substrate is moved to each process of the flat panel display manufacturing process and then moved (S400). Next, while the glass substrate passes through sensors (for example, edge sensors) provided in the lower part, signals are detected from these sensors (S410).

  The controller then reads the detected signal to determine the respective time required for the glass substrate to pass completely through the respective sensor, or from this detected signal the respective pulse. The number is counted (S420), and the respective time or the number of counted pulses is compared with a predetermined reference value (S430). As a result of comparison, if the time or the number of pulses read from each sensor is smaller than a predetermined reference value, it is determined that the glass substrate is broken. It is determined that there is no damage (S440). Further, the controller may be electrically connected to the main controller via an external device input / output interface. In this case, when the main controller determines that the glass substrate is broken by the controller, the controller controls the alarm device. The movement of the glass substrate can be stopped by generating an alarm signal or controlling the transfer device for transferring the glass substrate.

  FIG. 5 is a plan view showing an embodiment in which the detection device according to the present invention is applied to an in-line production system of a flat panel display device. FIG. 5 shows that the first glass substrate 10a is positioned and processed in the first process module (PM1), and the process in the first process module (PM1) is completed. The glass substrate 10b is in a state of being transferred and waiting for input to the second process module (PM2). In the second process module (PM2), the third glass substrate 10c is positioned and the second process is being performed. At this time, the processing is completed in the first process module (PM1), the second glass substrate 10b being transferred to the second process module (PM2) is the edge sensor 20a, which is located at the lower part of the transfer path, Whether or not the glass substrate is broken is determined by 20b, the reference sensor 20c, and a controller (not shown in FIG. 5). When breakage of the glass substrate is detected, the transfer controller is stopped or an alarm is generated by the alarm device under the control of the main controller electrically connected to the controller, and the second glass substrate 10b is Input to the process module (PM2) is blocked in advance.

  Further, when the processing is completed in the first process module (PM1) and the second glass substrate 10b being transferred passes through the edge sensors 20a and 20b and the reference sensor 20c located at the lower part of the transfer path, The signal waveform detected by the sensor is as shown in FIG. 2 for a normal glass substrate and as shown in FIG. 3 for a damaged glass substrate.

  Moreover, the process which determines the presence or absence of the damage of a glass substrate is performed by reading such a signal waveform with a controller according to the flow shown in FIG. In the embodiment of FIG. 5, only the first process module (PM1) and the second process module (PM2) are disclosed. However, the damage detection apparatus according to the present invention is limited to such two process modules. In addition, it can be applied to a plurality of process modules, and the position of the sensor can also be changed by a transfer process before and after processing in each module of the glass substrate. It will be understood by the contractor.

  FIG. 6 is a plan view showing an embodiment in which the detection device according to the present invention is applied to a cluster production system of a flat panel display device. FIG. 6 shows that the first process substrate (PM1), the second process module (PM2), and the third process module (PM3) have a first glass substrate 10a, a second glass substrate 10b, and a second process module, respectively. 3 glass substrates 10c are positioned and are in process, and after the processing is completed in these process modules, the fourth glass substrate 10d transferred to the transport chamber 50 waits for loading into the load lock LL. It is in a state of being. In addition, the processing in the process module is completed at the lower part of the load lock LL, and the fifth glass substrate 10e transferred from the transport chamber 50 is loaded and positioned. The upper part of the load lock LL has each process. A glass substrate (not shown) waiting for loading into the transport chamber 50 is positioned for loading into the module.

  The first glass substrate 10a, which has been processed in the first process module (PM1), is transferred to the transport chamber 50, and the edge sensors 20a and 20b are located at the lower part near the entrance of the transport chamber 50. And a controller (not shown in FIG. 6) determines whether or not the glass substrate is broken. In addition, after the processing is completed in each process module, the fourth glass substrate 10d transferred to the transport chamber 50 is transferred to the lower portion of the load lock LL and is positioned in the lower portion near the entrance of the load lock. Whether or not the glass substrate is broken is determined by the edge sensors 20a and 20b, the reference sensor 20c, and a controller (not shown in FIG. 6). If the breakage of the first glass substrate 10a or the fourth glass substrate 10d is detected, an additional process module or an additional process module from the transport chamber 50 is controlled under the control of the main controller electrically connected to the controller. Transfer to the load lock LL is interrupted, or an alarm device generates an alarm, so that the glass substrate can be interrupted in advance to the additional process module or the load lock LL.

  Although not shown, a reference sensor 20c may be further provided in addition to the edge sensors 20a and 20b in the lower part of the transport chamber 50 near the entrance of the first process module (PM1). Edge sensors 20a and 20b and a reference sensor 20c are provided near the entrance of the transport chamber 50 from the second process module (PM2) and near the entrance to the transport chamber 50 from the third process module (PM3). Also good.

  When the first glass substrate 10a processed in the first process module (PM1) passes through the edge sensors 20a and 20b located in the lower part near the entrance of the transport chamber 50, signals detected by these sensors The waveforms are as shown in FIGS. 2A and 2B for a normal glass substrate, and as shown in FIGS. 3A and 3B for a damaged glass substrate. In addition, after the processing is completed in each process module, the fourth glass substrate 10d transferred to the transport chamber 50 passes through the edge sensors 20a and 20b and the reference sensor 20c located at the lower part near the entrance of the load lock LL. The signal waveforms detected by these sensors are as shown in FIG. 2 for a normal glass substrate and as shown in FIG. 3 for a damaged glass substrate.

  Moreover, the process which determines the presence or absence of the damage of a glass substrate is performed by reading such a signal waveform with a controller according to the flow shown in FIG. The damage detection apparatus according to the present invention is not limited to a cluster production system that supports three process modules, but can be applied to a cluster production system that additionally supports a plurality of process modules. Those skilled in the art will understand that the position of the sensor can also be changed according to the transfer process before and after processing in each process module of the glass substrate.

  FIG. 7 shows an arrangement of conventional photosensors for detecting breakage of an edge portion of a glass substrate in a cluster production system. In such a conventional method, before the glass substrate is put into each process module, the presence or absence of breakage of each edge of the glass substrate is detected by an optical sensor (a To n). However, such a conventional detection method requires that the glass substrate be stopped in the transport chamber in order to detect breakage of the edge portion of the glass substrate, and the six process modules (PM1 to PM6) are installed. In the case of the cluster production system to be supported, there is a problem that all 14 optical sensors (a to n) are required for detection.

  Although the present invention has been described with reference to the accompanying drawings, the present invention is not limited to the embodiments disclosed in the drawings, and those skilled in the art can make modifications and changes according to the spirit of the present invention. It will be understood that such modifications and variations are also within the scope of the present invention.

It is a schematic block diagram which shows the damage detection apparatus of the edge part of the glass substrate by this invention. When a normal glass substrate passes through the optical sensor of the detection device according to the present invention, a plan view showing the positional relationship between the optical sensor and the normal glass substrate, and each optical sensor located below the normal glass substrate is detected. It is the graph which showed the waveform of the signal which is taken with respect to the time axis. When a broken glass substrate passes through the optical sensor of the detection device according to the present invention, a plan view showing a positional relationship between the optical sensor and the damaged glass substrate, and detection from each optical sensor located below the damaged glass substrate. It is the graph which showed the waveform of the signal which is taken with respect to the time axis. 3 is a flowchart illustrating in detail a method for detecting breakage of an edge portion of a glass substrate according to the present invention. It is a top view which shows embodiment which the detection apparatus by this invention was applied to the in-line production system of a flat panel display apparatus. It is a top view which shows other embodiment with which the detection apparatus by this invention was applied to the cluster production system of a flat panel display apparatus. It is a figure which shows arrangement | positioning of the photosensor of the conventional system for detecting the failure | damage of the edge part of a glass substrate in a cluster production system.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Glass substrate, 10a-10e ... 1st glass substrate-5th glass substrate, 20 ... Sensor, 22 ... Reflecting plate, 20a, 20b ... Edge sensor, 20c ... Reference sensor, 30 ... Controller, 40 ... Maine Controller, 50 ... Transport chamber, LL ... Load lock, PM1 to PM6 ... First process module to sixth process module.

Claims (12)

At least two sensors that are provided below or above the position where the glass substrate is to be moved, and that recognize the glass substrate and generate a signal while the glass substrate passes;
The at least two sensors are electrically connected to the at least two sensors, receive signals from the at least two sensors, and the glass substrate passes above or below the at least two sensors. Read out the signal received from each of them to determine the respective time required for the glass substrate to completely pass through the respective sensor, or while the glass substrate passes over the top or bottom of the at least two sensors. Counting the number of each pulse from the signals received from said at least two respective sensors and comparing each such determined time or the number of each counted pulse with a predetermined reference value And a controller for determining whether the glass substrate is broken or not. Breakage detection device of the edge portion of the glass substrate characterized by.   The controller compares the respective determined time or the number of each counted pulse with a predetermined reference value, and the time or the number of pulses is smaller than the predetermined reference value; 2. It is determined that there is breakage of the glass substrate, and if it is the same, it is determined that there is no breakage of the glass substrate. .   The at least two sensors are provided with a pair of left and right at the lower or upper part of the position where the left and right edge portions of the glass substrate are to move, and an edge that recognizes the glass substrate and generates a signal while the glass substrate passes The damage detection device for an edge portion of a glass substrate according to claim 1 or 2, further comprising a sensor.   The glass substrate according to claim 3, wherein the at least two sensors further include a reference sensor positioned between the edge sensors and generating a synchronization signal with respect to a signal generated from each edge sensor. Edge detection device.   The apparatus for detecting breakage of an edge portion of a glass substrate according to claim 1, wherein the at least two sensors are transmissive sensors.   The apparatus for detecting breakage of an edge portion of a glass substrate according to claim 1 or 2, further comprising a main controller electrically connected to the controller.   When the main controller determines that the glass substrate is broken by the controller, the alarm controller is controlled to generate an alarm signal, or the transfer device that transfers the glass substrate is controlled to stop the movement of the glass substrate. The breakage detection device for an edge portion of a glass substrate according to claim 6. A step of recognizing the glass substrate and generating a signal while the glass substrate passes by at least two sensors provided at a lower portion or an upper portion of the position where the glass substrate is to be moved;
A controller electrically connected to the at least two sensors and receiving signals from the at least two sensors, wherein the at least two sensors while the glass substrate passes above or below the at least two sensors. Read the signal received from each sensor to determine the respective time it takes for the glass substrate to pass completely through the respective sensor, or the glass substrate can be above or below the at least two sensors. Counting the number of each pulse from the signals received from said at least two respective sensors during transit;
Comparing the respective determined times or the number of counted pulses with a predetermined reference value by the controller to determine whether the glass substrate is broken or not. A method for detecting breakage of an edge portion of a glass substrate.   The step of determining whether or not the glass substrate is broken includes comparing each of the determined times or the number of counted pulses with a predetermined reference value, and determining the time or the number of pulses. 9. The glass according to claim 8, wherein the glass substrate is determined to be damaged when the reference value is smaller than the reference value, and the glass substrate is determined not to be damaged when they are the same. A method for detecting breakage of an edge portion of a substrate.   Among the at least two sensors, a pair of left and right sensors provided at the lower or upper part of the position where the left and right edge portions of the glass substrate should move, and while the glass substrate passes, recognize the glass substrate and signal 10. The method for detecting breakage of an edge portion of a glass substrate according to claim 8 or 9, wherein:   11. The glass according to claim 10, wherein, among the at least two sensors, a sensor positioned between the pair of left and right sensors generates a synchronization signal for a signal generated from the pair of left and right sensors. A method for detecting breakage of an edge portion of a substrate.   When the controller determines that the glass substrate is broken, a main controller electrically connected to the controller controls an alarm device to generate an alarm signal, or controls a transfer device that transports the glass substrate. The method for detecting breakage of an edge portion of a glass substrate according to claim 8, further comprising a step of stopping the movement of the glass substrate.

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