JP2006264804A - Flotation unit for large flat panel, and non-contact carrying device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flotation unit, capable of coping with carrying of a large glass substrate by avoiding flexure of the large glass substrate while increasing flotation quantity to the whole surface of the large glass substrate, for example. <P>SOLUTION: This flotation unit 1 is provided with a base member 2 of a prescribed size corresponding to the large glass substrate G to be carried, an air feed part 21 provided on a bottom surface 20 of the base member 2, a porous part 23 provided in an upper surface 22 of the base member 2, an air discharge part 24 to feed air from the air feed part 21 into the base member 2, and out of the porous part 23 to flow out from the upper surface 22 of the base member 2 toward the bottom surface 20, while sending it out of the base member 2, a flow regulator 25 provided on the air discharge part 24, an edge hole part 27 formed in an edge part 26 in the upper surface 22 of the base member 2 to make the substrate G float by dynamic pressure air, and a flow speed regulator 28 to adjust the flow speed of air flowing from the edge hole part 27. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a floating unit that floats and transports a large flat panel used in an LCD, PDP, or the like in a non-contact manner, and a non-contact transport apparatus using the same.

With the recent increase in the size of flat panel displays, large glass substrates are transported in the manufacturing process. Conventional contact methods such as a roller method and a belt method are causing damage to the glass substrate due to spots, scratches, and the like.
In the technical field of levitation conveyance by air that can avoid such damage to the glass substrate, various non-contact conveyance apparatuses such as the air levitation apparatus of Patent Document 1 have been developed.
JP-A-2004-262608

However, in such a non-contact conveying apparatus, as the glass substrate becomes larger and thinner, the “deflection” of the glass substrate has become a big problem.
Below, the problem of the bending accompanying the enlargement of a glass substrate, another problem, and these causes are demonstrated.

The larger the glass substrate, the larger the amount of deflection, and accordingly, it is required to increase the flying height of the glass substrate (the flying height from the conveying surface of the flying unit to the glass substrate). Incidentally, it is expected that a large glass substrate of the sixth generation (1500 × 1800) or later will require a flying height of about 3 millimeters or more.
In order to increase the flying height, it is necessary to supply more air to the flying unit. Due to the large air volume, air can be blown out to the glass substrate, and depending on the method of discharging from the glass substrate, the air flow may cause deflection. .

The cause of this phenomenon will be described with reference to FIG.
In FIG. 4, the air blown from the floating unit 100 through the outlet 102 of the perforated plate 101 forms an air film 103 between the glass substrate G and the floating unit 100, and this becomes a floating amount.
In general, the flying height increases correspondingly when the blowing air volume is large.
However, in proportion to this, when the wind speed V when the blown air flows out from the periphery of the glass substrate G increases, the lower static pressure Ps2 becomes lower than the upper static pressure Ps1 in the overhang portion G1 of the glass substrate G. As a result, a pressing force from above as shown by an arrow F in FIG. 4 works and the glass substrate G bends.
In order to prevent this bending phenomenon, it is necessary to keep the outflow wind speed V low, which is in contradiction with the necessity of increasing the air volume, and a device that balances both is required.

Next, the place where the glass substrate G bends and causes a contact accident is a portion G1 where the glass substrate G is overhanging mainly from the floating unit conveyance surface (the surface of the porous plate 101). An accident at the transfer portion S between the adjacent manufacturing line 110 and this portion is a problem that cannot be avoided structurally in a manufacturing line that requires flexibility in the layout of the manufacturing apparatus.
That is, as shown in FIG. 5, when the overhang distance of the transfer portion S increases, the glass substrate G is bent due to its own weight, leading to a contact accident.
Therefore, it is necessary to partially increase the flying height of the glass substrate G according to the overhang distance.

  Next, in the manufacturing process such as film formation on the glass substrate G, the state of the glass surface changes, and there is a possibility that different bending occurs in each process, and it is necessary to cope with this.

The next problem is that among the plurality of floating units 100... Constituting the production line, the floating unit 100 on which the glass substrate G is mounted and the floating unit 100 on which the glass substrate G is not mounted A difference will occur.
This is resistance due to the weight of the glass substrate G, and therefore, in the process of transporting the glass substrate G as shown in FIG. 6, more air (blowing air volume A) is generated from the floating unit 100 on which the glass substrate G is not mounted. A phenomenon occurs in which the air blown out and the air blown out from the levitation unit 100 on which the essential glass substrate G is placed (the amount of blown air B) decreases.
In order to make the flying height of the glass substrate G constant in any floating unit 100, it is necessary to have a function of blowing constant air from each floating unit 100 regardless of the presence or absence of the glass substrate G.

  Summarizing the above problems and issues, a new configuration of a floating unit for avoiding the bending of the glass substrate while increasing the floating amount with respect to the entire surface of the large glass substrate, and when there is a deflection in a part of the large glass substrate, Since it is impractical to raise the floating amount of the entire glass substrate, a new structure of a floating unit for raising the partial floating amount, and a large glass in a conveyance path constituted by these floating units This is a novel configuration of a non-contact transfer device for ensuring an efficient flying height of the substrate.

  A base body of a predetermined size, an air supply portion provided on the bottom surface of the base body, a porous portion provided on the upper surface of the base body, and flows into the base body from the air supply portion and blows out from the porous portion The air that floats the glass substrate from the top surface of the base body to the bottom surface of the base body and exhausts the outside of the base body, a flow rate regulator provided in the exhaust section, and an edge portion of the base body The levitation unit is provided with an edge hole portion that blows out air that levitates the glass substrate from the upper surface of the base body (the invention according to claim 1).

  The size of the glass substrate is not particularly limited, but a large glass substrate is assumed.

  In the above invention, the number of installed air supply units substantially corresponds to the number of installed exhaust units, and is provided along the conveying direction of the glass substrate. Item 2).

  In the above invention, the opening ratio of the holes forming the porous portion is from a dense state to a sparse state except for the central portion from the edge portion intersecting the transport direction of the glass substrate. It was set as the unit (Invention of Claim 3).

  In the non-contact conveyance apparatus in which the conveyance path is configured by the levitation unit, a constant air volume device is provided for each levitation unit (the invention according to claim 4).

  According to the levitation unit of the present invention, it is possible to control the air flow or to partially apply the dynamic pressure to the deflection of the overhang portion of the glass substrate while maintaining a predetermined levitation amount, for example, a levitation amount of 3 mm or more. By taking a countermeasure for increasing the floating amount, it is possible to provide a non-contact conveyance device using a floating unit having a function of floating the entire large glass surface on average.

Embodiments of the above inventions will be described with reference to the drawings.
FIG. 1 is a perspective view of a floating unit according to the embodiment, FIG. 2 is a longitudinal sectional view and a plan view of the unit, and FIG. 3 is a longitudinal sectional view of a non-contact conveying apparatus assembled by the unit.
In these drawings, the same components are denoted by the same reference numerals, and redundant description is omitted.
A large flat panel for a flat panel display such as a liquid crystal display (LCD), a plasma display (PDP), a field emission display (FED), and an electroluminescence display (EL) is assumed as a floating object of the floating unit. These panels include a glass substrate and a synthetic resin substrate such as a plastic. In the following description, a glass substrate is used as a representative example.

As shown in FIGS. 1 and 2, the levitation unit 1 according to the embodiment includes a base body 2 having a predetermined size corresponding to a large glass substrate to be transported (hereinafter also simply referred to as a substrate), and the base body 2. An air supply portion 21 provided on the bottom surface 20, a porous portion 23 provided on the upper surface 22 of the base body 2, and flows into the base body 2 from the air supply portion 21 and flows out of the porous portion 23. Air that floats the substrate G (hereinafter also referred to as air) flows out from the top surface 22 of the base body 2 to the bottom surface 20 and exhausts out of the base body 2, and is provided in the exhaust section 24. The flow rate adjuster 25 and the edge hole portion 27 formed on the edge portion 26 of the upper surface 22 of the base body 2 and floating the substrate G by dynamic pressure air are provided.
A wind speed adjuster 28 for adjusting the wind speed of the air flowing out from the edge hole 27 may be attached.

  Clean air purified by a HEPA filter or the like is supplied to the air supply unit 21 through a blower duct, and a wide range is formed between the upper surface 22 and the substrate G above it by the air blown from the porous unit 23. A gas film is formed on the substrate body G, and a conveyance path is configured by applying a force in the conveyance direction X by a conveyance roller (not shown) disposed on both sides of the base body 2.

The base body 2 has a cubic shape and is airtight except for the holes of the air supply part 21, the holes of the porous part 23, the holes of the exhaust part 24 and the holes of the edge hole part 27. A predetermined volume of air is stored inside the base body 2 and air having a substantially uniform pressure is blown out from the porous portion 23.
For example, a metal such as stainless steel or aluminum is used as the material of the base body 2, but any material can be used as long as airtightness can be maintained.

  The specific predetermined sizes of the vertical dimension and the horizontal dimension of the base body 2 may correspond to the size of the substrate G to be levitated and transported. With such a size, the layout of the transport path Can be handled flexibly.

The air supply portion 21 is formed at two locations on the bottom surface 20 of the base body 2 so as to be substantially along the transport direction X of the substrate G and before and after the substrate G.
The air supply unit 21 only needs to allow air necessary for the flying height of the substrate G to flow into the base body 2, and the diameter, the arrangement position, and the number of arrangement are not limited to the above configuration.

The porous portion 23 is formed by a plurality of holes formed in the upper surface 22.
These holes are formed, for example, by punching the upper surface 22. By using such punching holes, the air blowing resistance can be weakened and the flying height can be increased.
These numerous holes are arranged in a direction substantially intersecting the transport direction X of the substrate G as shown in FIG. 1 and the like, and the pitch of the rows and columns is punched out narrowly on the upper surface 22 before and after the transport direction X. As it approaches the center of the upper surface, the pitch of rows and columns is increased and punched out. That is, the aperture ratio is punched in a dense state at the edge portion 26 that intersects the transport direction X, and the aperture ratio is punched into a sparse state as it approaches the central portion of the upper surface 22.
This is because the gas film tends to swell at the center of the substrate G, and so on, in accordance with the characteristics at the time of transporting the substrate G.

  In addition to the arrangement of the holes in the porous portion 23, the hole shape, the hole diameter, and the like may be designed and determined so that a predetermined flying height can be obtained with respect to the substrate G.

The exhaust part 24 includes an inflow port 240 formed in the upper surface 22, an exhaust port 241 formed in the bottom surface 20, and a connecting cylinder 242 provided between the inflow port 240 and the exhaust port 241.
Similar to the air supply unit 21, the exhaust unit 24 is installed so as to substantially follow the transport direction X of the substrate G, and is formed between the air supply units 21.
These exhaust parts 24, 24 only need to be able to adjustably exhaust air that can give a predetermined flying height to the substrate G to the outside of the base body 2 as will be described in detail later. The shape, size, position, number, and the like of the 241 and the connecting cylinder 242 are not limited to the above configuration.
Further, the number 2 of the exhaust units 24 corresponds to the number 2 of the air supply units 21 and the balance between the air supply and the exhaust is achieved. However, the number of the exhaust units 24 may be limited to these numbers. Absent.

  The flow rate regulator 25 adjusts the amount of air discharged from the exhaust part 24 and is attached to the exhaust port 241. The flow regulator 25 can adjust the opening area of the discharge port 241. For example, it can appropriately cope with the bending of the glass substrate or the state where the central portion of the substrate G swells, which changes for each manufacturing process.

  The edge hole 27 allows air to flow out locally to increase the flying height to the overhanging portion (end G1) of the substrate G to be transferred to the adjacent floating unit 1, manufacturing apparatus or the like. Thus, the wind speed V1 of the air is adjusted by the wind speed adjuster 28 so that the flying height can be controlled.

The operational effects of the levitation unit 1 configured as described above will be described with reference to FIG.
Air of an air supply amount Q1 flowing into the base body 2 from the air supply port 21 is blown out from the porous portion 23 toward the substrate G, forms a gas film, and is discharged from the four end portions of the substrate G. The quantity Q2 and the discharge quantity Q3 discharged from the exhaust section 24 are divided and flow out (Q1 = Q2 + Q3).
When the discharge amount Q2 increases, the flow velocity of the wind increases, and the end portion G1 of the substrate G tends to be bent as described above. Therefore, the discharge amount Q3 is increased to reduce the discharge amount Q2. This adjustment is performed by the flow rate regulator 25.
Therefore, the flying unit 1 can avoid the bending of the substrate G while increasing the flying height with respect to the entire surface of the substrate G.
In addition, the floating unit 1 can flexibly cope with the bending and distortion of the substrate G that changes in each manufacturing process.

  In addition to the bending due to the dead weight of the substrate G and the bending and distortion caused by the manufacturing process, by adding the wind velocity V1 from the edge hole 27, the bending is caused by the dynamic pressure of the air flow, and more distortion points are lifted The levitation unit 1 can be made to operate. The wind speed is adjusted by the wind speed adjuster 28.

Next, a non-contact conveying apparatus constituted by the floating unit 1 is illustrated in FIG.
As described above, since the air passage resistance of the hole of the porous portion 23 is relatively small, the increase ratio of the resistance is large due to the weight of the substrate G. When the non-contact transfer apparatus is configured by the plurality of floating units 1, Depending on the presence or absence, the amount of blown air may increase or decrease greatly.
In order to solve this problem, constant air volume devices 4A to 4D are attached to the air duct 3 connected to the floating units 1A to 1D so that a constant air volume is blown out from each unit 1A to 1D regardless of the presence or absence of the substrate G. The configuration.
The constant air volume devices 4A to 4D set the air volume in advance according to the air volume required by the respective floating units 1A to 1D, and always have a function of blowing the set air volume so that the floating units 1A to 1D. It can be set as the non-contact conveyance apparatus which can set an air volume efficiently with respect to the large sized glass substrate in the conveyance path comprised by these.

The perspective view of the levitation unit concerning an embodiment, Sectional view and plan view of the unit, Side view of non-contact transfer device by the unit, Explanatory drawing of a conventional example, Explanatory drawing of a conventional example, Explanatory drawing of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Floating unit 2 Base body 20 Bottom surface 21 Supply part 22 Upper surface 23 Porous part G Substrate 24 Exhaust part 25 Flow controller 26 Edge part 27 Edge hole part 28 Air speed regulator 240 Inlet 241 Outlet 242 Connecting cylinder X Conveying direction G1 End of board Q1 Air supply amount Q2 Discharge amount Q3 Discharge amount V1 Air velocity 1A to 1D Levitation unit 4A to 4D Constant air amount device

Claims (4)

A base body of a predetermined size,
An air supply portion provided on the bottom surface of the base body;
A porous portion provided on the upper surface of the base body;
An exhaust part that flows into the base body from the air supply part, blows out from the porous part and floats the glass substrate, flows out from the top surface of the base body to the bottom surface of the base body, and exhausts outside the base body;
A flow rate regulator provided in the exhaust section;
An edge hole portion that is attached to an edge portion of the base body and blows out air that floats the glass substrate from the upper surface of the base body;
A levitation unit characterized by comprising   2. The levitation unit according to claim 1, wherein the number of installed air supply units substantially corresponds to the number of installed exhaust units and is provided along a conveyance direction of the glass substrate.   2. The aperture ratio of the holes forming the porous portion is changed from a dense state to a sparse state as the center portion is approached from the edge portion intersecting the transport direction of the glass substrate. Levitation unit.   The non-contact conveyance apparatus by which a conveyance path is comprised by the levitation unit of Claim 1, The constant air volume apparatus was installed for every levitation unit, The non-contact conveyance apparatus characterized by the above-mentioned.

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