JPH09169427A - Floating device and board carrying device provided with this floating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a floating device for restricting the adhesion of dust or the like and the generation of damage as small as possible and for preventing the deflection, and to provide a board carrying device in the case of handling a material having a relatively large flexibility such as a glass board. SOLUTION: Floating force is given by the energy of a bend of the pseudo standing wave based on the acoustic wave generated by an oscillator 11. Consequently, in the case of carrying a glass board 3 or the like, a belt is made to contact with the only ends of the glass board 3 so as to support the glass board, and the adhesion of dust or the like and the generation of damage is restricted as small as possible, and the floating force is given to a central part of the glass board 3 so as to restrict the deflection at nearly zero and prevent the generation of habit of bending.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a levitation device that applies levitation force based on ultrasonic waves to an object, and a substrate transfer device that includes the device and transfers a substrate.

[0002]

2. Description of the Related Art A glass substrate used as a liquid crystal display or the like has dust (par) on its main surface.
It is necessary to avoid the adherence of the tiles and the generation of scratches even if they are minute. Therefore, caution is required when transporting the glass substrate.

Conventionally, there is a roller conveyor shown in FIGS. 13 and 14 as an example of a so-called single-wafer carrying means for carrying glass substrates one by one.

As shown in the figure, this roller conveyor comprises a plurality of driving rollers 1 and driven rollers 2 and an endless thin belt 4 which is wound around each of the rollers and the lower surfaces of both ends of the glass substrate 3 come into contact with each other. The driving roller 1 has a driving means (not shown) for rotationally driving the driving roller 1.

That is, the belt 4 is driven by the rotation of the drive roller 1, and the glass substrate 3 is conveyed (indicated by the arrow A).

In the carrying means having such a structure, the glass substrate 3
Since the thin belt 4 only comes into contact with the edge of the glass substrate 3 and contacts the edge of the glass substrate 3 while avoiding the central portion, the problem of dust adhesion and damage is reduced.

On the other hand, in the manufacturing line, in addition to the above-described transportation, the glass substrate is temporarily placed in a certain place. In that case, the transportation of the glass substrate is also performed in order to avoid the above problems. Similarly to the above, the glass substrate 3 is placed on both sides of the glass substrate 3 on a stationary table as supporting means.

[0008]

However, the above-mentioned prior art has the following problems.

That is, in recent years, with the application of liquid crystal displays to televisions, videos, personal computers, etc., the demand for glass substrates has increased, and their shapes have become larger. Since the glass substrate is very thin, it bends due to its own weight when it is supported at both ends as described above, and the amount of deflection is considerably large especially for a large substrate.

If the amount of flexure is too large, the glass substrate may be plastically deformed, that is, may have a bending tendency, and if it is seriously damaged by static stress due to internal strain, the glass substrate may be broken.

Here, the result of actually measuring the amount of bending of the glass substrate will be described. The measurement conditions are as follows.

First, the glass substrate prepared as a sample has a length, a width and a thickness of 650 mm, 550 mm and 0.7 mm, respectively. This glass substrate is shown in FIG.
As shown in FIG. 5, it was placed between the two support blocks 6 and the amount of flexure B due to its own weight was measured. However, the positions of both support blocks 6 were appropriately changed, the orientation of the glass substrate 3 was changed, and the measurement was performed in each of the length direction and the width direction. That is, in FIG. 15, the symbol A indicates the length or width dimension of the glass substrate 3.

Further, the quantity indicated by the symbol C in FIG.
That is, the amount by which the upper edge of the end of the glass substrate 3 separates from the upper surface of the support block 6 when the glass substrate 3 is bent was also measured.

The measurement results are shown in the following table.

[0015]

[Table 1]

As described above, the deflection is the first problem when the size of the substrate is increased. Incidentally, since the amount of bending is proportional to the fourth power of the supporting span (the above-mentioned dimension A), it greatly changes even if the dimension of the substrate is increased a little.

From the above point of view, the structure shown in FIGS. 17 and 18 is generally adopted as one method for suppressing the bending of the substrate.

As shown in the figure, a roller conveyor comprising a driving roller 1, a driven roller 2, a belt 4 and the like is arranged not only at both ends of the glass substrate 3 but also at the center thereof.
With this configuration, the maximum amount of bending can be set to, for example, 0.1 mm or less.

However, in this structure, since the number of belts 4 is large, and moreover, not only both ends of the glass substrate 3 but also the central part thereof are contacted, the chances of dust adhesion and damage are increased correspondingly, and the yield is increased. There is an inconvenience that it leads to a decrease.

The present invention has been made in view of the above-mentioned drawbacks of the prior art, and its main purpose is to handle an object having a relatively large flexibility such as a glass substrate. To provide a levitation device that contributes to making the amount of deflection almost zero while suppressing the adhesion and damage of dust to the substrate, and a substrate transfer device that includes the levitation device and that transfers a substrate such as a glass substrate. is there.

It is another object of the present invention to provide a substrate transfer device which can achieve other effects in addition to the above.

[0022]

In order to achieve the above main object, a levitation apparatus according to the present invention comprises a vibrating body and ultrasonic wave exciting means for exciting the vibrating body, and It is configured to give levitation force to the object by the energy of the node of the pseudo standing wave based on. In order to achieve the same main purpose, the levitation device according to the present invention used when the flexible object is placed at a predetermined place is provided with a support means for supporting the object, a vibrating body, and the vibrating body. Ultrasonic wave exciting means for exciting the object, and is configured to apply a levitation force to the object by the energy of the node of the pseudo standing wave based on the sound wave emitted by the vibrating body to prevent the object from bending. Also,
In order to achieve the same main purpose, a substrate transfer apparatus according to the present invention has a transfer unit for transferring a substrate, a vibrating body, and an ultrasonic wave exciting unit for exciting the vibrating body, and the vibrating body emits the vibration. The energy of the node of the pseudo standing wave based on a sound wave gives a levitation force to the substrate to prevent the substrate from bending.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION According to the present invention, when a glass substrate having a thin plate shape and a relatively large flexibility is placed or conveyed at a certain place, it is bent while suppressing adhesion and damage of dust to the glass substrate as much as possible. Is implemented to prevent

[0024]

Embodiments of the present invention will now be described with reference to the accompanying drawings.

With respect to each substrate transfer device (including the levitation device) described below as various embodiments, the same components as those of the conventional device described above are designated by the same reference numerals.

Further, in these substrate transfer devices, the substrate to be transferred is a rectangular glass substrate, and 3 is used as a reference numeral for this glass substrate, as in the above description of the conventional example. To do.

1 and 2 show a substrate transfer device (including a levitation device) as a first embodiment of the present invention.

The substrate carrying device comprises a carrying means for carrying and carrying the glass substrate 3, and a means for giving a levitation force to the glass substrate 3 in order to prevent the glass substrate 3 from bending.

The above-mentioned conveying means is made to endlessly be wound around a plurality of driving rollers 1 and driven rollers 2 and these rollers so that the outer peripheral portion of the glass substrate 3, specifically, the lower surfaces of both side end portions come into contact with each other. It comprises a belt 4 and a driving means (not shown) for rotationally driving the driving roller 1.

The means for applying a levitation force to the glass substrate 3 has a vibrating body 11, an ultrasonic vibration generating section 12, and an oscillator 13 (shown in FIG. 2). The ultrasonic vibration generator 12 and the oscillator 13 constitute an ultrasonic wave excitation means for exciting the vibrating body 11.

The ultrasonic exciting means and the vibrating body 11 are collectively referred to as a levitation device.

The vibrating body 11 is made of duralumin or the like into a rectangular plate shape and has an outer diameter dimension of the glass substrate 3.
Is formed to be smaller than the outer diameter dimension of the. Then, it is arranged below the glass substrate 3 which is conveyed by the above-mentioned conveying means.

On the other hand, the ultrasonic vibration generator 12 has a horn 16 which is connected to the vibrator 11 by means of a countersunk screw 15 (shown in FIG. 1) and the like. Duralumin or the like is selected as the material of the horn 16. As shown in FIG. 2, a vibrator 18 is coupled to the horn 16 on the side opposite to the coupling side of the vibrating body 11, that is, on the lower end side. The electrode 18 a of the vibrator 18 and the oscillator 13 are connected by the connection cable 20, and the vibrator 1
8 is driven by the oscillator 13 to generate ultrasonic vibration.

Note that, in FIG. 2, the vibration direction of ultrasonic vibration by the vibrator 18 and the horn 16 is indicated by an arrow U. In this way, the vibrator 18, and thus the horn 16, vibrates vertically.

The horn 16 has a flange portion 16a formed at its nodal point portion.
The flange portion 16a is fastened to the lower half portion and the case 22 accommodating the vibrator 18 by a bolt (not shown) and a packing 23.

As shown in FIG. 1 and FIG.
An ultrasonic vibration generator 12 for vibrating the vibrating body 1 and the vibrating body 11 is mounted on a movable table 25 that can reciprocate in the direction in which the glass substrate 3 is to be conveyed. The movable table 25 is moved by a drive unit (not shown) in synchronization with the transfer of the glass substrate 3 by the transfer unit (including the belt 4).

Next, the operation of the substrate transfer device having the above structure will be described.

First, the oscillator 13 shown in FIG. 2 is activated in advance, and the vibrating body 11 is excited. The vibrating body 11 performs bending vibration as indicated by the symbol S based on the longitudinal vibration (indicated by the arrow U) transmitted through the horn 16.
Therefore, the length L (see FIG. 1) and the width B of the vibrating body 11
(The same) is set to the resonance length of the flexural vibration based on the vibration transmitted from the horn 16. Specifically, horn 1
Vibration of 19.5 KHz is applied through 6 and vibrating body 1
1 10~30μmp _- vibrates with a amplitude of p.

That is, the vibration nodes of the vibrating body 11 appear at predetermined intervals in the length direction and the width direction, respectively, and vibrate in a lattice-like vibration mode.

The dimensions of the vibrating body 11, the resonance frequency and its amplitude, and the form of the vibration mode can be set as appropriate.

With the vibrating body 11 continuing to vibrate as described above, the glass substrate 3 to be conveyed is placed horizontally so that both side end portions thereof ride on the left and right belts 4.
Then, the glass substrate 3 is given a levitation force to its central portion by the energy of the node of a pseudo standing wave (described later) based on the sound wave emitted by the vibrating body 11. Therefore, the bending due to its own weight as shown by the chain double-dashed line in FIG. 3 hardly occurs, and as shown by the solid line in FIG. 3, it is maintained in a substantially completely horizontal state.

In this state, the driving roller 1 is rotationally driven to drive the belt 4, and the glass substrate 3 is conveyed (indicated by an arrow A in FIG. 1). Since the movable table 25 moves in the same direction and at the same speed in synchronization with the transportation of the glass substrate 3 (indicated by an arrow D in FIG. 1), the glass substrate 3 can always receive a constant levitation force. , Flexure is prevented.

As described above, in the substrate transfer apparatus, the belt 4 is supported by contacting only the end portion of the glass substrate 3 so that the adhesion and damage of dust to the glass substrate 3 can be suppressed as much as possible. By giving the above-mentioned levitation force to the central portion of the glass substrate 3, the bending is set to almost 0, and the occurrence of bending tendency and the like is prevented.

In this way, the bending is prevented by using ultrasonic waves in a non-contact manner, and the contact with the belt 4 is minimized, so that the yield is improved.

The node of the pseudo standing wave is the vibration body 11
Since it is positioned at least 1/4 wavelength away from the surface of the glass substrate, and the position of this node is the position where the glass substrate 3 exists, the distance between the glass substrate 3 and the vibrating body 11 is kept relatively large. There is no risk of contact.

The levitation force can be generated by blowing compressed air from below the glass substrate 3, for example. In this method, the compressed air is blown onto the glass substrate 3.
In addition to the device for injecting toward the air, auxiliary equipment such as a compressor for compressing and continuously supplying air is required, which causes an increase in cost. In the case of utilizing ultrasonic vibration as in the present invention, as long as a device for emitting ultrasonic waves is provided, the other problems are only the problem of power consumption.

Here, the result of an experimental study on the levitation phenomenon using the energy of the node of the pseudo standing wave will be described.

<Levitation Phenomenon Using Pseudo Low-Wave Nodes> Sound waves radiated from the flexural diaphragm propagate only in the direction of the incident angle θ that satisfies the wave number matching. This sound wave forms an apparent standing wave sound field with the reflector mounted above the diaphragm. This is called a pseudo-standing wave, and its wavelength satisfies the relationship of the following formula (1). This time, we confirmed the levitation of the material with a flat bottom by receiving the energy of this pseudo standing wave node on the surface.

In FIG. 4, λ _{q is a} pseudo-standing wavelength λ _{a is} a wavelength in the air θ is a radiation angle, and λ _q and λ _a satisfy the following expressions. λ _q = λ _a / sin θ (1)

<Measurement of levitation force> The levitation force provided by the sound field formed by the pseudo standing wave was measured by the device shown in FIG. The levitating object is a rectangular parallelepiped made of aluminum (102 * 70 * 15).
mm), which is sufficiently heavy and is hung on an electronic balance.

The levitation force is the difference between the values indicated by the scale when the vibrator is on and when it is off. The striped flexure mode is excited on the diaphragm. The parameters of this vibration are as shown below. Resonance frequency f = 17.0 [kHz] Radiation angle θ = 54 ° [deg. ] Stripe mode interval d = 16.5 [mm] Wavelength in air λ _a = 20.0 [mm] Pseudo-standing wavelength λ _q = 24.5 [mm]

Note that, as shown in FIG. 6, the measurement is also performed in the case where the levitation object is surrounded by an aluminum plate, and is compared with the case without the enclosure.

[0053]

[Table 2]

<Experimental Results> First, the change in the levitation force when the distance between the diaphragm and the levitation object was changed was examined. The amplitude of the diaphragm is constant at 8 μm. FIG. 7 shows the results. In FIG. 7, the vertical axis plots a value divided by the bottom area of the levitated object.

The large levitation force obtained when the distance between the diaphragm and the levitating object is close to 0 is the ultrasonic radiation pressure disclosed in Japanese Patent Laid-Open No. 7-244155 proposed by the present applicant. It is due to the levitation phenomenon based on. There is one peak at a distance of 10-20 mm from the diaphragm, which corresponds to the node of the pseudo standing wave.

The peak value in the case with the enclosure is more than double that in the case without the enclosure. At a distance from the diaphragm, there is a considerable difference in the levitation force depending on the presence or absence of the enclosure. When there is an enclosure, peaks appear at half wavelength intervals of the pseudo standing wave. However, if there is no box, it is difficult to read the positions of the nodes after the second wavelength from the graph. This indicates that the emitted sound waves do not reach the object and are diverging.

It has been confirmed that the breakage of a rectangular size floppy disk (0.0053 gf / cm ² ) floats at an amplitude of about 10 μm.

FIG. 8 shows the value of the levitation force when the levitation object is fixed at a half wavelength of the pseudo standing wave from the diaphragm and the amplitude of the diaphragm is changed. It can be seen from this graph that the levitation force is proportional to the square of the amplitude.

FIG. 9 shows the relationship between the input power of the vibrator and the levitation force. In this case, there is a proportional relationship. Assuming that the conversion efficiency of the oscillator is 100%, the radiation pressure is proportional to the energy density of the entire surface of the object, and the input power divided by the area of the diaphragm is considered as the energy density of the front surface of the object. It is reasonable.

<Summary of Experiment> In the node of the pseudo standing wave formed by the flexural diaphragm, the levitation of the flat bottom was confirmed. Moreover, the distribution of the levitation force in the sound field was measured. It was confirmed that the levitation force can be increased by making good use of the sound waves emitted from the diaphragm. It was confirmed that the levitation force and the input power are in a proportional relationship.

Next, a substrate transfer device as a second embodiment of the present invention will be described with reference to FIG. However, the same applies to the substrate transfer device of the third embodiment and the levitation device as the fourth embodiment, which will be described later, but the substrate transfer device of the second embodiment is shown in FIGS. 1 and 2 except for the portions described below.
The substrate transporting apparatus has the same configuration as the substrate transporting apparatus as the first embodiment shown in FIG. 1, and the description of the entire apparatus is omitted because it is redundant, and only the main parts will be described.

As shown in the figure, in this substrate carrying device, the vibrating body 11 is elongated and extends over substantially the entire area of the carrying path of the glass substrate 3 by the carrying means (including the belt 4).

That is, the vibrating body 11 does not move, and with respect to the glass substrate 3 carried by the carrying means,
The levitation force is given by the wide vibration area.

On the other hand, in the substrate transfer apparatus as the first embodiment described above, the vibrating body 11 is formed short,
It is mounted on the movable table 25, and the movement of the movable table 25 follows the conveyance of the glass substrate 3.

In the substrate transfer apparatus of the second embodiment described above,
The movable table 25 and its driving means are not required, the structure is simple, and the cost can be easily reduced.

In the substrate transfer apparatus of the first embodiment, since the vibrating body 11 is short and the vibrating area is narrow, the vibration from the ultrasonic vibration generating section 12 is effectively transmitted to the entire vibrating area. A substantially uniform levitation force may be generated over the entire surface of the vibrating body 11. When the vibrating body 11 is long like the substrate transfer apparatus of the second embodiment, it is inevitable that the vibration energy is attenuated toward the end in the longitudinal direction, and it is not easy to obtain a substantially uniform levitation force over the entire surface. Absent.

Next, a substrate transfer device as a third embodiment of the present invention will be described with reference to FIG.

As shown in the figure, in the substrate transfer apparatus, the short vibrating body 11 similar to that in the first embodiment is used.
However, a plurality of glass substrates 3 are arranged in parallel along the conveyance path of the glass substrate 3 at equal intervals. The ultrasonic vibration generator 12 is individually provided for each of these vibrators 11.

In this structure, the glass substrate 3 conveyed by the above-mentioned conveying means (including the belt 4 etc.) moves so as to pass between the vibrating bodies 11 arranged in parallel, and receives a levitation force.

In this configuration, the glass substrate 3
The maximum levitation force applied to the vibrating body 11 is maximum when the glass substrate 3 is located right above each vibrating body 11, and is the smallest when the glass substrate 3 passes through the midpoint between the vibrating bodies 11 adjacent to each other. Even when receiving the minimum levitation force, the levitation force is set so that the amount of bending of the glass substrate 3 falls within an allowable value (a size that does not cause a bending tendency or the like).

In the third embodiment described above, a plurality of vibrators 11 and ultrasonic vibration generators 12 are required, so that it is not necessarily advantageous in terms of cost. However, on the other hand, there is an advantage that a required levitation force can always be obtained regardless of the position of the glass substrate 3.

Further, in the third embodiment, each vibrator 11 is
Is fixed, there is no need to immediately return the movable table 25 to the original position before the transfer as in the case of the first embodiment when one glass substrate 3 is transferred, and one after another without waiting time. The glass substrate can be continuously transported, which is efficient. This efficiency is also the same for the substrate transfer device of the second embodiment in which the vibrating body 11 is also in the fixed state.

By the way, in the manufacturing line, in addition to the above-described transportation, the glass substrate 3 is temporarily placed in a certain place, and in that case also, dust adhesion and damage to the glass substrate may occur. In order to avoid the problem, the glass substrate 3 is placed on the stationary table at its outer peripheral portion, specifically, both end portions, in the same manner as during the above-mentioned transportation.

FIG. 12 shows a levitation device including a stationary table as a supporting means for supporting the glass substrate as described above and a means for giving a levitation force to the glass substrate in order to prevent the glass substrate from bending. is there.

As shown in the figure, the glass substrate 3 has a columnar (or prismatic) support portion 31 of the stationary table at both end portions thereof.
It is placed horizontally on top. Below the glass substrate 3 supported by the supporting portion 31, the same vibrating body 11 and ultrasonic vibration generating portion 12 as the devices of the first and third embodiments described above are provided. There is.

That is, the glass substrate 3 is the vibrating body 1
Levitation force is given to the central part by the energy of the node of the pseudo standing wave based on the sound wave emitted by 1. Therefore, there is no bending due to its own weight, and it is kept almost completely horizontal.

As described above, in the levitation device,
The stationary table is brought into contact with and supported by only the end portion of the glass substrate 3 so that the adhesion and the damage of dust to the glass substrate 3 are suppressed as much as possible, while the levitation force is applied to the central portion of the glass substrate 3. As a result, the bending is set to almost zero, and the occurrence of bending tendency is prevented.

In this way, the bending is prevented by using ultrasonic waves in a non-contact manner, and the contact with the stationary table is minimized, so that the yield is improved.

Further, as in the case of the above-described transport, the position of the node of the pseudo standing wave, that is, the position where the glass substrate 3 exists is sufficiently separated from the surface of the vibrating body 11, so that the glass substrate 3 and the vibrating body are There is no risk of 11 contacting.

Furthermore, in the same way as described above, in the levitation device,
Compared to those that give levitation force by the injection of compressed air,
It is advantageous in terms of cost.

Although the substrate handled in each of the above-described embodiments is a glass substrate, the present invention can be applied to an apparatus handling another substrate such as a silicon wafer.

Further, according to the present invention, it is necessary to prevent the adhesion of dust and the generation of scratches in addition to such various substrates, and
It is useful when handling an object having a relatively large flexibility because it is a thin or soft material.

Further, in each of the above-mentioned embodiments, the shape of the vibrating body 11 is a rectangular plate shape, but the shape of the vibrating body may be appropriately changed according to the shape of the object to which the levitation force is applied. Of course.

Further, although the transporting means provided for transporting the glass substrate 3 in the substrate transporting apparatus of the above-described first to third embodiments is a roller conveyor, it may be replaced with transporting means of various other configurations. Good. Similarly, in the flotation device of the fourth embodiment, the stationary table provided as the supporting means for supporting the glass substrate 3 is not limited to the one according to the present embodiment, but various structures can be used. Is.

In addition, in each of the above embodiments, the levitation force based on ultrasonic waves is used for the purpose of preventing the bending of the object, but it may be used for other purposes.

[0086]

As described above, in the levitation device and the substrate transfer device according to the present invention, the levitation force is applied by the energy of the node of the pseudo standing wave based on the sound wave generated by the vibrating body. Therefore, when the glass substrate or the like having a relatively large flexibility is placed or conveyed at a predetermined location, the placing table or the belt is brought into contact with and supported by only the end portion of the glass substrate or the like. The adhesion and damage of dust to the glass substrate or the like can be suppressed as much as possible, while the levitation force is applied to the central portion of the glass substrate or the like, so that the bending can be made almost zero and the occurrence of bending tendency can be prevented. In this way, the bending is prevented by using ultrasonic waves in a non-contact manner, and the contact with the belt or the like is minimized, so that the yield is improved. Also, the above pseudo standing wave section
It is separated from the surface of the vibrating body by at least a quarter length, and since the position of this node is the position where the glass substrate or the like exists, the distance between the glass substrate and the vibrating body is kept relatively large. There is no danger of both people coming in contact with each other. The levitation force can be generated, for example, by blowing compressed air from the lower side of the glass substrate or the like, but in this method, in addition to the device for injecting compressed air, in order to continue supplying compressed air. Ancillary equipment such as a compressor is required, resulting in an increase in cost. In the case of utilizing ultrasonic vibration as in the present invention, as long as an apparatus for generating ultrasonic waves is provided, the other problems are only power consumption.

[Brief description of the drawings]

FIG. 1 is a perspective view of an essential part of a substrate transfer apparatus as a first embodiment of the present invention.

2 is a main part of the substrate transfer device shown in FIG.
It is a front view containing a partial cross section.

FIG. 3 is a front view of a main part including a partial cross section showing a situation in which the glass substrate is prevented from being bent in the substrate transfer device shown in FIGS.

FIG. 4 is a diagram for explaining a relationship between a sound wave actually radiated from a flexible diaphragm and a pseudo standing wave.

FIG. 5 is a front view showing a measuring device for measuring the levitation force applied by the sound field formed by the pseudo standing wave.

FIG. 6 is a schematic perspective view showing a state in which a floating object is surrounded by an aluminum plate.

FIG. 7 is a graph showing the results of examining changes in the levitation force when the distance between the diaphragm and the levitation body is changed.

FIG. 8 is a graph showing the value of the levitation force when the levitation object is fixed at a half wavelength of the pseudo standing wave from the diaphragm and the amplitude of the diaphragm is changed.

FIG. 9 is a graph showing the relationship between the input power of a vibrator and the levitation force.

FIG. 10 is a perspective view of a main part of a substrate transfer device as a second embodiment of the present invention.

FIG. 11 is a perspective view of an essential part of a substrate transfer device as a third embodiment of the present invention.

FIG. 12 is a perspective view of a main portion of a levitation device as a fourth embodiment of the present invention.

FIG. 13 shows a state where a glass substrate is being conveyed by a roller conveyor as a first conventional example,
It is a longitudinal cross-sectional view perpendicular to the transport direction.

14 is a perspective view showing a main part of the roller conveyor shown in FIG. 13 and a glass substrate.

FIG. 15 is a front view including a partial cross-section showing a situation in which the amount of bending of the glass substrate is being measured.

16 is an enlarged view of a portion E in FIG.

FIG. 17 shows a state where a glass substrate is being conveyed by a roller conveyor as a second conventional example,
It is a longitudinal cross-sectional view perpendicular to the transport direction.

18 is a perspective view showing a main part of the roller conveyor shown in FIG. 17 and a glass substrate.

[Explanation of symbols]

 1 Drive Roller 2 Driven Roller 3 Glass Substrate 4 Belt 11 Vibrator 12 Ultrasonic Vibration Generator 13 Oscillator 16 Horn 18 Transducer 20 Connection Cable 22 Case 25 Movable Platform 31 (of Stationary Platform) Carrier

Claims (8)

[Claims] 1. A vibrating body and an ultrasonic wave exciting means for exciting the vibrating body, wherein a levitation force is applied by the energy of a node of a pseudo-standing wave based on a sound wave emitted by the vibrating body. Levitation device. 2. A support means for supporting an object, a vibrating body, and an ultrasonic wave exciting means for exciting the vibrating body, wherein the energy of a node of a pseudo-standing wave based on a sound wave emitted by the vibrating body is used. A levitation device, which applies a levitation force to an object to prevent the object from bending. 3. The levitating apparatus according to claim 2, wherein the object is a substrate, and the supporting means supports the outer peripheral portion by making the substrate substantially horizontal. 4. A transport means for transporting a substrate, a vibrating body, and an ultrasonic wave exciting means for exciting the vibrating body, wherein the energy of a node of a pseudo standing wave based on a sound wave emitted by the vibrating body is used. A substrate transfer apparatus, wherein a levitation force is applied to a substrate to prevent the substrate from bending. 5. The substrate transfer apparatus according to claim 4, wherein the transfer unit transfers the substrate while making the substrate substantially horizontal and supporting an outer peripheral portion thereof. 6. The substrate transfer apparatus according to claim 4, wherein the vibrating body moves in synchronization with the transfer of the substrate by the transfer unit. 7. The substrate transfer apparatus according to claim 4, wherein the vibrating body is elongated and extends over substantially the entire area of the substrate transfer path. 8. The substrate transfer apparatus according to claim 4, wherein a plurality of the vibrating bodies are arranged in parallel along a transfer path of the substrate.