JP2006035343A - Method for detecting cracking of glass plate and device therefor, and method for polishing glass plate and device therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect a cracking sound of a glass plate during polishing distinctly from cracking sounds or the like of the other glass plates. <P>SOLUTION: Sounds are collected by a microphone 30. A high-frequency sound is extracted by a filter 40. Next, a sound level, which becomes maximum in a prescribed time T1 (T1=10 milliseconds), is acquired for each prescribed time T1 regarding the high-frequency sound extracted by the filter 40. After that, a sound level, which is minimum among the sound levels acquired in a past prescribed time T2 (T2=300 milliseconds) from the present, is acquired as a stationary sound level. Then, one count is added when a ratio of the present sound level acquired for each T1 and the stationary sound level exceeds a prescribed value (2.5). Third and fourth steps are repeated for each prescribed time T1 until the count reaches ten counts. When the count reaches ten counts within a prescribed time T3 (5 seconds), it is determined that cracking occurs to the glass plate G, and a signal showing the cracking is outputted to a control part 24. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a glass plate crack detection method and apparatus, and a glass plate polishing method and apparatus for detecting a crack generated in a glass plate during processing when the glass plate is processed.

  In the glass manufacturing process, various processes (cutting, chamfering, drilling, polishing, heat forming, air cooling strengthening, etc.) are performed on the glass plate. For example, in a glass substrate used for a liquid crystal display, minute irregularities and undulations on the surface cause distortion of the image. Therefore, the minute irregularities and undulations are removed by a polishing apparatus. As such a polishing apparatus, there has been known a polishing apparatus including a moving table on which a glass plate is placed and conveyed, and a plurality of polishing heads arranged continuously above the moving table. According to this polishing apparatus, the glass plate is gradually polished by the plurality of polishing heads while the glass plate is conveyed by the moving table.

  By the way, the glass plate breaks during polishing of the glass plate by the polishing apparatus, and if the polishing operation is continued in this state, the polishing pad of the polishing head is damaged by the broken glass piece, and the glass plate and the polishing liquid processing man-hour are reduced. In addition, there is a problem that other glass plates are adversely affected during continuous polishing. For this reason, it is necessary to detect the crack of a glass plate at an early stage, and to stop a grinding | polishing apparatus rapidly. When the glass plate is broken, stopping the processing machine quickly is the same for processing machines in other processing steps.

Patent Document 1 discloses a detection device that detects a break in a window glass for an automobile. This glass breakage detection device is a device that extracts a frequency specific to glass breakage from a sound collected by a microphone using a filter, and determines that the glass breakage occurs during detection of this frequency. In addition, this detection device has a normal warning mode that gives a short warning when a glass breaking sound is detected, and a special warning mode that gives a long warning when a glass breaking sound is detected. The transition is made after detecting one glass breaking sound in the normal alert mode as a preliminary stage. Then, after the transition to the special alert mode, if the glass breaking sound is not detected again within a certain time, the normal alert mode is restored.
JP-A-4-195298

  However, for example, in a factory where a glass plate polishing apparatus is installed, in addition to the sound of polishing a glass plate, sound similar to cracking of the glass plate, for example, ear processing after cutting the glass plate, cullet processing of defective glass plates The sound when performing etc. is mixed. For this reason, as in the detection device of Patent Document 1, simply by extracting the frequency of the glass breaking sound with a filter, the cracking sound of the glass plate being polished is distinguished from the polishing sound and the cracking sound of other glass plates. There was a problem that it was difficult to do.

  The present invention has been made in view of such circumstances, and a method for detecting cracks in a glass plate capable of detecting the cracking sound of a glass plate being processed separately from the processing sound, cracking sound of other glass plates, and the like. Another object of the present invention is to provide a glass plate polishing method and apparatus therefor.

  In order to achieve the above object, the invention according to claim 1 processes the glass plate by the processing means, collects the processing sound generated during the processing by the sound collecting means, and collects the processed sound. A sound of a predetermined frequency is extracted from the filter by a filter, and a crack of the glass plate is determined by comparing a current sound level of the extracted sound with a steady sound level within a predetermined time in the past from the present. A crack detection method is provided.

  In order to achieve the object, the invention described in claim 6 is a processing means for processing a glass plate, a sound collection means for collecting a processing sound of the glass plate by the processing means with a microphone, and the sound collection A filter that extracts a sound of a predetermined frequency from the processed sound collected by the means, and by comparing a current sound level and a steady sound level within a past predetermined time from the present for the sound extracted by the filter, And a determination means for determining a crack in the glass plate.

  A part of the energy released from the glass plate as the glass plate is processed propagates as sound waves. This phenomenon is called acoustic emission, and it was experimentally confirmed that the frequency of the sound wave generated when the glass plate was broken was a high-frequency sound of 3 kHz or more as described in claims 3 and 8. On the other hand, the processing sound of the glass plate is a wide range of sound from low frequency to high frequency, which is lower than the sound level of the cracking sound of the glass plate, but also includes the same 3 kHz or higher sound as the cracking sound of the glass plate. .

  According to the first and sixth aspects of the invention, the processed sound is collected by the sound collecting means, the high frequency sound of 3 kHz or higher is extracted by the filter, and the stationary sound, cracking sound and similar sound are first acquired. To do. Next, the determination means determines the breakage of the glass plate included in the processed sound by comparing the current sound level and the steady sound level within the past predetermined time from the present for the sound extracted by the filter. . As described in claims 4 and 9, the sound level is the amplitude of the processed sound, and the steady sound level is the processed sound generated when the glass plate being processed is not cracked. It is the magnitude of the amplitude. Therefore, the determination means compares the current sound level with a steady sound level without a cracking sound, and determines that a crack has occurred in the glass plate when the current sound level is a predetermined amount greater than the steady sound level. .

  And when it determines with the determination means having cracked in a glass plate, like the grinding | polishing method and its apparatus of Claim 5, 10, a grinding | polishing control means controls a grinding | polishing means and stops grinding | polishing of a glass plate. .

  In order to achieve the above object, the invention according to claim 2 processes the plate glass by the processing means, collects the processing sound generated during the processing by the sound collecting means, and collects the processed sound from the collected processing sound. A first step of extracting a sound having a predetermined frequency by a filter; a second step of acquiring a maximum sound level within a predetermined time T1 for the extracted sound every predetermined time T1; A third step of acquiring a minimum sound level among the sound levels acquired in the second step as a steady sound level within a predetermined time T2 (T2> T1), a current sound level and the steady sound; The fourth step of adding 1 count when the ratio to the level exceeds a predetermined value, and the third step and the fourth step are repeated every predetermined time T1, and the predetermined time T3 (T3>) When a predetermined count is reached within T2) Provides a crack detection method characterized in that it comprises a fifth step of determining a crack in the glass plate has occurred, the.

  In order to achieve the above object, a seventh aspect of the present invention provides a processing means for processing a glass plate, a sound collecting means for collecting processing sound of the glass plate by the processing means with a microphone, and the sound collecting A filter for extracting a sound of a predetermined frequency from the processed sound collected by the means, and a sound level that is maximum within a predetermined time T1 in the first acquisition step for the sound extracted by the filter in a predetermined time Acquired every T1, and in the second acquisition step, the minimum sound level among the sound levels acquired in the first acquisition step is steady within the past predetermined time T2 (T2> T1) from the present. Acquired as a sound level, and in the addition step, when the ratio between the current sound level and the steady sound level acquired in the second acquisition step exceeds a predetermined value, 1 count is added, The predetermined time T1 And the adding step are repeated, and when the predetermined count is reached within a predetermined time T3 (T3> T2), determination means for determining that a crack has occurred in the glass plate is provided. Providing equipment.

  According to the second and seventh aspects of the present invention, the processed sound is collected by the sound collecting means, the above-described high frequency sound of 3 kHz or higher is extracted by the filter, and the steady sound, cracking sound and similar sound are first obtained. get. Next, the determination unit obtains the maximum sound level within a predetermined time T1 for each sound extracted by the filter every predetermined time T1. Next, within the past predetermined time T2 (T2> T1) from the present, the minimum sound level among the acquired sound levels is acquired as a steady sound level. Next, when the ratio between the current sound level and the steady sound level exceeds a predetermined value, one count is added, and the third step (second acquisition step) and the fourth step are performed every predetermined time T1. When the predetermined count is reached within a predetermined time T3 (T3> T2), it is determined that a crack has occurred in the glass plate. As a result, it is possible to eliminate the ear processing after cutting of the glass plate that occurs irregularly around the processing machine, the cullet processing sound of the defective glass plate, etc. from the judgment target sound, and when a crack occurs during processing Only cracking sounds that are generated periodically can be set as judgment target sounds. Therefore, it is possible to detect only the cracking sound being processed from many mixed sounds.

  And when it determines with the determination means having cracked in the glass plate, like the grinding | polishing method and apparatus of Claim 5, 10, a grinding | polishing control means controls a grinding | polishing means and stops grinding | polishing of a glass plate. Let

  As described above, according to the method and apparatus for detecting cracks in a glass plate and the polishing method and apparatus according to the present invention, it is possible to detect early and reliably that a crack has occurred in a glass plate during processing. it can. In addition, calculation for detecting cracks in a glass plate can be calculated and judged with a simple arithmetic expression without using FFT (Fast Fourier, Cosine, and Sine Transform). Can do. In particular, when the processing is polishing, it is possible to quickly detect the cracking of the glass plate being polished and stop the polishing means quickly, so that the polishing pad can be prevented from being damaged. The number of liquid processing steps can be reduced, and furthermore, the influence on other glass plates can be prevented during continuous polishing, which is effective. Thereby, quality, an operating rate, and a yield improve, respectively.

  Hereinafter, preferred embodiments of a glass plate crack detection method and apparatus, a polishing method and apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 shows a main part of a glass plate polishing apparatus 12 to which the glass plate crack detection apparatus 10 of the embodiment is applied. The polishing apparatus 12 is a polishing apparatus that polishes one side of a glass plate G (for example, one side of 700 mm to 2500 mm and a thickness of 0.5 mm to 1.3 mm) to a flatness necessary for a glass substrate for a liquid crystal display, and is a polishing target. The table 14 conveys the glass plate G, and the polishing head 16 installed above the table 14. The glass plate G before polishing is placed on the table 14 on the upstream side of the table 14 and then positioned on the lower side of the polishing head 16 by the movement of the table 14. The upper surface in FIG. 1 is polished. During polishing, a polishing slurry such as a cerium oxide aqueous solution is supplied to the upper surface of the glass plate G from a slurry supply unit (not shown) installed in the vicinity of the polishing head 16. Further, as the polishing pad 18, for example, a foamed polyurethane type or a suede type is used. In the embodiment, the polishing apparatus 12 is exemplified as the glass plate processing means. However, the polishing apparatus 12 is not limited to this, and the glass plate cutting device, chamfering device, drilling device, heat forming device, or air cooling is not limited thereto. It may be a strengthening device.

  A spindle 20 is fixed to the upper part of the polishing head 16, and a rotation / lifting device (polishing means) 22 is connected to the spindle 20. The rotation / elevating device 22 is controlled to rotate and elevate in synchronization with the conveyance timing of the glass sheet G by the table 14 by a control unit (polishing control means) 24 that comprehensively controls the entire polishing device 12. That is, the rotation / lifting device 22 controls the lifting mechanism such as a hydraulic cylinder device to place the polishing head 16 in a retracted position above the polishing position in advance, and the glass plate G is positioned below the polishing head 16. Is moved downward from the retracted position to the polishing position at the timing of being conveyed. By this operation, the polishing pad 20 is pressed against the upper surface of the glass plate G with a predetermined pressure. Thereafter, the rotation / lifting device 22 controls the motor to move the polishing head 16 to a predetermined rotation speed (for example, 50 to 250 rpm). ) To rotate. In addition, as the polishing apparatus 12, a continuous polishing type polishing apparatus in which a plurality of polishing heads 16 are arranged in parallel above the table 14 may be applied. While being intermittently transported, it is gradually polished by a plurality of polishing heads 16, 16... And finally polished to the required flatness. The shape of the polishing pad 16 may be circular or rectangular, and circular and rectangular polishing pads 16 may be mixed.

  The glass plate crack detection device 10 is composed of a microphone (sound collecting means) 30, an operation personal computer main body 32, a keyboard 34, and a display 36, and an algorithm for determining a glass plate G crack that occurs during polishing. Is built in a recording medium 38 such as a CD-ROM.

  The microphone 30 is installed in the vicinity of the polishing head 16 and collects the polishing sound generated from the glass plate G being polished. The microphone 30 collects sound generated from the rotating / lifting device 22 constituting the polishing device 12 and the moving device of the table 14 in addition to the polishing sound, and glass near the polishing device 12. It also collects cracking sounds that occur when cutting the ears after cutting and culleting the defective glass plate. That is, the microphone 30 collects not only the cracking sound during polishing but also sounds similar to the cracking sound of the glass plate and low to high frequency sounds generated from various devices. Sound information collected by the microphone 30 is converted into an electrical signal and transmitted to the personal computer main body 32.

  A display 36 is connected to the personal computer main body 32, and information obtained by processing the sound information collected by the microphone 30 by the personal computer main body 32 is displayed on the display 36.

  The displayed information includes, for example, the sound waveform shown in FIG. 2 and the sound waveform shown in FIG. FIG. 2 shows a sound waveform including a cracking sound. Among the sound waveforms, the sound waveform indicated by the symbol A is a filter 40 (see FIG. 4) in which sound collected by the microphone 30 is collected in the personal computer main body 32. ) Is the input sound waveform of the sound extracted by. The filter 40 is a filter that extracts a high frequency sound of 3 kHz or more, and a filter that extracts a high frequency sound of preferably 3 kHz to 12 kHz, more preferably 3.5 kHz to 6 kHz is used.

  The sound waveform indicated by symbol B has a maximum sound level (amplitude of polishing sound) within a predetermined time T1 (T1 = 10 msec (preferably 0.1 to 1000 msec, particularly preferably 1 to 100 msec)) every predetermined time T1. It is a sound waveform created and acquired. Furthermore, the sound waveform indicated by the symbol C has a sound level (polishing) that is the minimum of the acquired sound levels within a predetermined time T2 (T2 = 300 msec (preferably 1 msec to 10 sec, particularly preferably 100 to 1000 msec)). This is a sound waveform created to obtain the sound amplitude) as a steady sound level. The steady sound level mentioned here means the magnitude of the amplitude of the polishing sound that is generated when the glass plate G being polished is not cracked. The sound information sampling period is 40 kHz (25 μsec), preferably 20 to 60 kHz, and particularly preferably 30 to 50 kHz.

  On the other hand, FIG. 3 shows a sound waveform processed for determination, and this sound waveform is a waveform showing the ratio between the current sound level acquired every predetermined time T1 and the acquired steady sound level, In the figure, the ratio (threshold value) is set to 2.5, and the mark ■ is attached to the sound level exceeding the ratio. As a threshold value, 1-10 are preferable, Most preferably, it is 1.5-5.

  In addition, the personal computer main body 32 includes a determination unit 42 (see FIG. 4) that determines whether the glass plate G is broken based on sound information collected by the microphone 30. The determination unit 42 will be described later.

  Further, in the personal computer main body 32 of FIG. 1, a recording medium mounting unit 44 for detachably mounting the recording medium 38, and a recording medium interface (not suitable) for recording and reading information such as image data with respect to the recording medium 38. Are provided).

  The personal computer main body 32 stores a program for operating a CPU that performs overall control of the personal computer main body 32, a memory serving as a work area when the CPU executes processing, and various constants and networks related to processing of the personal computer main body 32. A hard disk is provided for recording various information such as connection information such as dial-up telephone numbers, addresses, and site addresses, calculation formulas, calculation tables, and the like for communication connection with the above communication device.

  Next, a crack determination method by the determination unit 42 built in the personal computer main body 32 will be described with reference to the flowchart of FIG. The determination unit 42 is programmed in a predetermined language so as to perform the following processing.

  Sound is collected by the microphone 30, and high-frequency sound of 3 kHz or higher is extracted by the filter 40 (step (S) 100, first step). As a result, low-frequency sounds generated from various devices such as the rotation / lifting device 22 and the table moving device are excluded from the determination target sound. Next, for the high-frequency sound extracted by the filter 40, first, the maximum sound level within the predetermined time T1 (T1 = 10 msec) is acquired every predetermined time T1 (step (S) 110, second Process). Next, within the past predetermined time T2 (T2 = 300 msec) from the present time, the minimum sound level among the acquired sound levels is acquired as a steady sound level (S120, third step, second acquisition step). ). Next, one count is added when the ratio between the current sound level acquired as T1 and the steady sound level exceeds a predetermined value (2.5) (S130, fourth step, addition step). . Then, the third step and the fourth step are repeated every predetermined time T1 until the count reaches 10 counts (S140), and the predetermined time T3 (5 sec (preferably 1 to 60 sec, particularly preferably 1 to 10 sec) is set. ) Within 10 counts (preferably 5 to 100, particularly preferably 10 to 20), it is determined that a crack has occurred in the glass plate G (fifth step), and the control unit 24 in FIG. The signal shown is output. Accordingly, the control unit 24 controls the rotation / lifting device 22 to stop the rotation of the polishing head 16 and raise the polishing head 16 from the polishing position to the retracted position, thereby stopping the polishing (S150).

  By this determination method, it is possible to eliminate the ear processing after cutting of the glass plate that is similar to the sound of glass breaking sound and the cullet processing sound of the defective glass plate from the determination target sound, and polishing. Only the cracking sound of the glass plate G that is regularly generated when a crack is generated can be detected as the determination target sound. Therefore, according to the determination method of the embodiment, only the cracking sound during polishing from the sound of a wide frequency band including low-frequency sound and high-frequency sound such as sound of polishing a glass plate and cracking sound of another glass plate. Can be detected.

  As described above, according to the crack detection device 10 of the glass plate G of the embodiment, it is possible to detect early and reliably that a crack has occurred in the glass plate G during polishing.

  In addition, the calculation for detecting cracks in the glass sheet G can be calculated and determined by a simple arithmetic expression without using FFT (Fast Fourier / Cosine / Sine Transform). be able to.

  Furthermore, since the cracking of the glass plate G during polishing can be detected at an early stage and the polishing apparatus 10 can be stopped quickly, damage to the polishing pad 18 can be prevented, and the man-hours for processing the glass plate G and the polishing liquid can be reduced. Furthermore, the influence on the other glass plate G can be prevented during continuous polishing. Thereby, quality, an operating rate, and a yield improve, respectively.

1 is a configuration diagram of a glass plate polishing apparatus to which a glass plate crack detection device according to an embodiment of the present invention is applied. Sound wave form of polishing sound collected by microphone Waveform diagram showing the ratio between the current sound level and the steady sound level Block diagram showing configurations of microphone, filter, and determination unit Flow chart of crack detection method by crack detector

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Glass plate crack detection device, 12 ... Glass plate polishing device, 14 ... Table, 16 ... Polishing head, 18 ... Polishing pad, 20 ... Spindle, 22 ... Rotation / lifting device, 30 ... Microphone, 32 ... Computer for calculation Main body, 34 ... keyboard, 36 ... display, 38 ... recording medium, 40 ... filter, 42 ... determination unit

Claims (10)

While processing the glass plate by the processing means, the processing sound generated during processing is collected by the sound collecting means, and the sound of a predetermined frequency is extracted from the collected processing sound by a filter,
A method of detecting a crack in a glass plate, comprising: determining a crack in the glass plate by comparing a current sound level with respect to the extracted processed sound and a steady sound level in a past predetermined time from the present. A first step of processing the plate glass by the processing means, collecting the processing sound generated during the processing by the sound collecting means, and extracting the sound of a predetermined frequency from the collected processing sound by a filter;
A second step of obtaining a maximum sound level for each of the extracted sounds at a predetermined time T1 within a predetermined time T1;
A third step of acquiring a minimum sound level among the sound levels acquired in the second step as a steady sound level within a predetermined time T2 (T2> T1) from the present;
A fourth step of adding one count when the ratio between the current sound level and the steady sound level exceeds a predetermined value;
The third step and the fourth step are repeated every predetermined time T1, and when the predetermined count is reached within the predetermined time T3 (T3> T2), a fifth step of determining that a crack has occurred in the glass plate. When,
A method for detecting cracks in a glass plate, comprising:   The glass plate crack detection method according to claim 1, wherein the sound having the predetermined frequency extracted by the filter is a high-frequency sound of 3 kHz or more including a glass cracking sound.   The sound level is the amplitude of the processed sound, and the steady sound level is the amplitude of the processed sound generated when the glass plate being processed is not cracked. The method for detecting a crack in a glass plate according to any one of claims 1, 2, and 3.   A method for detecting a crack in a glass plate according to any one of claims 1, 2, 3 or 4, wherein the glass plate is polished during polishing of the glass plate by a polishing means for polishing the glass plate as the processing means. When it is determined that a crack has occurred in the glass plate, polishing of the glass plate is stopped by a polishing control unit that controls the polishing unit. Processing means for processing a glass plate;
Sound collecting means for collecting the processing sound of the glass plate by the processing means with a microphone;
A filter for extracting a sound of a predetermined frequency from the processed sound collected by the sound collecting means;
Determination means for determining the breakage of the glass plate by comparing the current sound level and the steady sound level in the past predetermined time from the present for the sound extracted by the filter;
An apparatus for detecting a crack in a glass plate, comprising: Processing means for processing a glass plate;
Sound collecting means for collecting the processing sound of the glass plate by the processing means with a microphone;
A filter for extracting a sound of a predetermined frequency from the processed sound collected by the sound collecting means;
For the sound extracted by the filter, in the first acquisition step, a sound level that is maximum within the predetermined time T1 is acquired every predetermined time T1, and in the second acquisition step, the sound is acquired for a predetermined past time from the present time. Within T2 (T2> T1), the minimum sound level among the sound levels acquired in the first acquisition step is acquired as a steady sound level, and in the addition step, the current sound level and the second sound level are acquired. When the ratio of the steady sound level acquired in the acquisition step exceeds a predetermined value, 1 count is added, and the second acquisition step and the addition step are repeated every predetermined time T1, A determination means for determining that a crack has occurred in the glass plate when a predetermined count is reached within a predetermined time T3 (T3>T2);
An apparatus for detecting a crack in a glass plate, comprising:   The glass plate crack detection device according to claim 6 or 7, wherein the sound having the predetermined frequency extracted by the filter is a high-frequency sound of 3 kHz or more including glass cracking sound.   The sound level is the amplitude of the processed sound, and the steady sound level is the amplitude of the processed sound generated when the glass plate being processed is not cracked. The glass plate crack detection device according to any one of claims 6, 7 and 8.   The glass plate crack detection device according to any one of claims 6, 7, 8, or 9, wherein the determination is performed during polishing of the glass plate by a polishing unit that polishes the glass plate as the processing unit. An apparatus for polishing a glass plate, comprising: a polishing control unit that controls the polishing unit to stop polishing the glass plate when it is determined that a crack has occurred in the glass plate.

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