JP2007246274A - Conveying system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent an article from being deformed between conveying devices when the easily deformable article is conveyed. <P>SOLUTION: An air passage 12 and a nozzle 14 are formed on one of an upstream side conveyor 4 and a downstream side conveyor 6. Airflow is blown to the end bottom surface of a glass substrate 22 between the conveyors 4, 6. The end of the glass substrate 22 is detected by the reflecting position of light from a light source 16 which is changed whether the substrate 22 is present or not. After the end is detected, the nozzle 14 is moved for a predetermined time. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to conveyance of an easily-flexible article such as a glass substrate, and particularly relates to preventing bending in a gap between conveyance devices.

  In manufacturing a liquid crystal display or a plasma display, there is a step of conveying a large glass substrate one by one. And since the glass substrate used has an area of about 2 square meters and thickness is about several mm, it is very easy to bend. In the conveyance of such articles, a movable fire-proof shutter or the like is disposed between a conveyance device such as a conveyor and the conveyance device, so that a gap that is less than the width of one roller may occur. Even when a transport device other than the roller conveyor is used, a gap may be generated between the transport device and the transport device. Then, the tip of the substrate bends when passing between the transfer devices. This situation is shown in FIGS. 6 and 7, 8 is a roller inside the conveyor, and the glass substrate 22 reaches the roller 11 from the rollers 9 and 10 through the gap between the conveyors. Here, since there is a gap between the rollers 10 and 11 more than the others, the glass substrate 22 bends. For example, the substrate tip 24 collides with the roller 11 as shown by the solid line in FIG. 7 and vibrates as shown by the chain line in FIG. Guided to the top of the roller 11. If the tip of the substrate 22 bends, microcracks may occur in the substrate, or the thin film transistor on the substrate may be adversely affected, and vibration when contacting the roller 11 may have a greater effect.

Patent Document 1 discloses that a glass substrate is floated and conveyed by an air flow, and left and right ends of the glass substrate are guided and moved by rollers. However, it does not disclose bending or vibration of the glass substrate when passing between the transfer devices.
JP 2003-292153 A

An object of the present invention is to prevent an article from being bent between conveying apparatuses when conveying an easily bent article.
An object of the invention of claim 2 is to effectively prevent the deflection of the article by effectively using air.
An object of the invention of claim 3 is to more accurately control the deflection of the article.

  The transport system of the present invention is a system in which a plurality of transport devices are arranged at intervals from the upstream side to the downstream side, and articles are transferred horizontally between the transport devices at a certain height level. In order to prevent the downstream end of the article from falling below the certain height level when the article is transferred between transfer devices, an upward air flow is directed toward the bottom surface of the article. A nozzle for spraying is provided.

  Preferably, each of the conveying devices includes a plurality of rollers that support the article, and the tip of the article is between a downstream roller of the upstream conveying device and an upstream roller of the downstream conveying device. A sensor for detecting arrival and a control means for controlling the timing of blowing airflow from the nozzle according to the detection result of the sensor are provided.

  More preferably, a height sensor for detecting a height level of the article between the roller at the downstream end and the roller at the upstream end is provided, and the control unit according to the detection result of the height sensor. The air volume of the airflow from the nozzle is controlled. The height sensor may be the same as the sensor that detects the tip of the article.

  In this invention, when transferring the article between the transfer devices, the downstream end of the article does not fall below the certain height level, so that the nozzle faces upward from the nozzle toward the bottom surface of the article. Therefore, it is possible to prevent the article from being bent when the article is transferred between the transfer devices.

  Here, each conveyance device includes a plurality of rollers for supporting the article, and the leading edge of the article has arrived between the roller at the downstream end of the upstream conveyance device and the roller at the upstream end of the downstream conveyance device. If the control unit controls the sensor for detecting this and the timing of blowing the airflow from the nozzle according to the detection result of the sensor, the nozzle can be operated only when necessary. Further, it is possible to prevent the deflection of the article when the article is transferred between the roller conveyors.

  Further, when a height sensor for detecting the height level of the article is provided between the roller at the downstream end and the roller at the upstream end, and the control unit controls the air volume of the airflow from the nozzle according to the detection result of the height sensor. The deflection of the article can be controlled more accurately.

  In the following, an optimum embodiment for carrying out the present invention will be shown.

  1 to 5 show an embodiment and its modifications. The transport system 2 includes an upstream conveyor 4 and a downstream conveyor 6, 8 is an inner roller excluding the downstream end and upstream end side of the conveyors 4 and 6, 9 is a roller in front of the downstream end, 10 is A downstream end roller 11 is an upstream end roller. A gap having a width less than the addition of one roller 8 between the conveyors 4 and 6 is a cause of bending a flexible article such as the glass substrate 22.

  For example, an air passage 12 and a nozzle 14 are provided at the downstream end of the upstream conveyor 4, and an airflow is blown upward from the bottom of the glass substrate 22 through an air passage 12 from a fan or a compressor (not shown) to deflect the substrate tip 24 of the glass substrate 22. To prevent. The air passage 12 and the nozzle 14 may be provided at the upstream end of the downstream conveyor 6 or may be provided in the space between the conveyors 4 and 6. However, if it is provided in the space between the conveyors 4 and 6, a frame for the air passage 12 and the nozzle 14 is required, and it is difficult to provide it in a narrow gap.

  The air flow needs to be blown from the nozzle 14 from the time when the substrate tip 24 passes through the upper part of the nozzle 14 until it comes into contact with the roller 11 at the upstream end, particularly from before the substrate tip 24 comes into contact with the roller 11. This is until the uppermost part of the roller 11 is passed. Therefore, the position of the front end 24 of the substrate is detected by the light source 16 and the light detection unit 18 so that the airflow is used effectively and the downflow in the clean room is not disturbed. The reflection position differs between the case where the light from the light source 16 is reflected by the substrate 22 and the other cases, and this is detected by the light detection unit 18. For example, in the case of FIG. 1, when the light from the light source 16 is reflected by the substrate 22, the reflected light is incident on the light detection unit 18, and in other cases, the reflected light is not incident on the light detection unit 18. Moreover, it is preferable to make the height level of the board | substrate 22 between the conveyors 4 and 6 constant, and to make the bending amount of the board | substrate 22 constant. Since the incident position of the reflected light on the light detection unit 18 varies depending on the height level of the substrate 22, the height level of the substrate 22 can be detected by providing the light detection unit 18 with a lens and a CCD element. The tip 24 and the height level of the substrate 22 may be detected by separate sensors.

  The control unit 20 controls a compressor, a fan, or a pneumatic circuit device (not shown) that supplies an air flow to the nozzle 14. The controller 20 turns on the nozzle 14 until the substrate tip 24 passes through the highest position of the roller 11 at the upstream end after the substrate tip 24 is detected by the light detection unit 18, for example, and the air volume during this period is changed to the substrate. Feedback control is performed so that the height level of 22 matches the target value. Since the influence of the tip 24 coming into contact with the upstream roller 11 and the vibration is greater than the bending of the substrate 22 itself, the nozzle 14 is immediately before the substrate tip 24 starts to contact the roller 11. To pass through the top of the roller 11.

  1 and 2, the prevention of the bending of the substrate front end 24 has been described, but the same mechanism can be used to prevent the bending of the substrate rear end 26. In FIG. 3, the glass substrate 22 has almost passed through the upstream conveyor 4 and has been transferred to the downstream conveyor 6. At this time, if the substrate rear end 26 is bent downward when it leaves the roller 10, the position of the substrate rear end 26 is detected by the light detection unit 18. That is, when the light from the light source 16 is not reflected by the substrate 22, the reflected light is not incident on the light detection unit 18. Therefore, it is detected that the substrate rear end 26 has reached the vicinity of the nozzle 14. The nozzle 14 is operated by the control unit 20 during the time until it passes through the upper part of the nozzle 14. Since vibration due to contact with the roller 11 on the upstream side of the bending of the substrate 22 itself is a problem, it is not necessary to blow the airflow against the rear end 26 of the substrate.

  FIG. 4 shows a modification regarding the detection of the substrate tip 24 and the detection of the height level of the substrate 22. Reference numeral 28 denotes a new light source, and reference numeral 30 denotes a new light detection unit, which is the same as the light source 16 and the light detection unit 18 except that light is projected from the bottom surface side of the substrate 22 to detect reflected light. In the embodiment, the detection of the substrate front end 24 and the substrate rear end 26 and the detection of the height level of the substrate 22 are performed by the common light detection unit 18, but these may be performed by separate sensors. For detection, not only an optical sensor but also an ultrasonic sensor or the like can be used. For detection of the front end or the rear end of the substrate 22, a capacitance sensor or the like is provided vertically so as to sandwich the substrate 22. It is also possible to detect the difference in the dielectric constant. Similarly, an ultrasonic source and an ultrasonic sensor may be provided above and below the glass substrate 22 to detect a difference in sound speed between the substrate 22 and air. In addition, when a horizontal moving means 32 indicated by a chain line in FIG. 4 is provided and the substrate leading end 24 of the substrate 22 is detected by the light detection unit 30, it synchronizes with the horizontal movement of the substrate 22 so as to blow an airflow near the bottom of the substrate leading end 24. Then, the nozzle 12 may be moved.

  In the embodiment, the substrate 22 is prevented from being bent by the airflow from the nozzle 14, but as shown in FIG. 5, the diameter may be increased in the order of the roller 8 to the roller 9 ′ and the roller 10 ′ in the upstream conveyor 4 ′. . Then, the substrate 22 is lifted slightly upward when passing through the rollers 9 ′ and 10 ′, and comes into contact with the top of the roller 11 almost smoothly. However, it is difficult to accurately determine the bending amount of the substrate 22 and determine the diameters of the rollers 9 'and 10'.

  The examples show the conveyance of a glass substrate for a liquid crystal display or a plasma display. However, the embodiment is suitable for conveyance of an easily-flexible article, particularly an article having a small area and a low thickness because of its large area and thin thickness. Further, in the embodiment, the conveyance between the upper and lower roller conveyors is shown, but the type of the upstream or downstream conveying device itself is arbitrary, and a nozzle is used to prevent the tip 24 of the substrate 22 from being bent by a gap therebetween. 14 may be provided. Although the substrate front end 24 is detected by the light detection unit 18 in the embodiment, when the substrate 22 is marked, the position of the substrate front end 24 may be estimated from the marking to control the nozzle 14.

In the embodiment, the following effects can be obtained.
(1) It is possible to prevent the substrate tip 24 from being bent and to prevent vibration when the substrate tip 24 comes into contact with the roller 11.
(2) Since the nozzle 14 is operated only for the time necessary to prevent the substrate 22 from being bent, it is efficient. Further, the air volume during this period is feedback controlled so that the bending of the substrate 22 becomes constant, and the substrate can be transferred between the conveyors under a certain condition.
(3) The flexure of the substrate rear end 26 can be reduced similarly.
(4) If the nozzles 14 are installed on either of the upper and lower conveyors 4, 6, it is possible to prevent bending in a slight gap between the conveyors 4, 6.

Side view of main part of transfer system of embodiment Partial enlarged side view of FIG. The figure which shows the rear end detection of the glass substrate in an Example The figure which shows the modification of the edge part detection of the glass substrate in an Example. The figure which shows the other structure for the bending prevention of a glass substrate. The figure which shows the bending of the glass substrate between the conveying apparatuses in a prior art example. The figure which expands and shows the contact part of the downstream roller and glass substrate in the prior art example of FIG.

Explanation of symbols

2 Conveying System 4 Upstream Conveyor 6 Downstream Conveyor 8 Roller 9 Roller Before the Downstream End 10 Downstream End Roller 11 Upstream End Roller 12 Air Passage 14 Nozzle 16, 28 Light Source 18, 30 Light Detection Section 20 Control Section 22 Glass Substrate 24 Substrate tip 26 Substrate rear end

Claims (3)

A system in which a plurality of conveying devices are arranged at intervals from an upstream side to a downstream side, and articles are transferred horizontally between the conveying devices at a certain height level and conveyed,
In order to blow an upward air flow toward the bottom surface of the article so that the downstream end of the article does not fall below the certain height level when the article is transferred between transfer devices. A transfer system characterized by comprising a nozzle. Each of the conveying devices includes a plurality of rollers that support the article, and the leading edge of the article has arrived between the downstream roller of the upstream conveying apparatus and the upstream roller of the downstream conveying apparatus. The transport system according to claim 1, further comprising: a sensor that detects air flow; and a control unit that controls timing of blowing airflow from the nozzle according to a detection result of the sensor. A height sensor for detecting a height level of the article between the downstream end roller and the upstream end roller is provided, and the control unit detects from the nozzle according to the detection result of the height sensor. The conveyance system according to claim 2, wherein the air volume of the air flow is controlled.

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