JP2006161940A - Non-contact supporting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To ensure original effects in a high-accuracy flotation region while suppressing a great increase in cost. <P>SOLUTION: Between a high-accuracy floating suction mixing part 5 having a relatively fixed floating amount and a low-accuracy floating table 3, a porous floating part 4 is provided having medium accuracy. A difference in accuracy between flotation on the floating suction mixing part 5 and flotation on both sides is therefore reduced. Thus, high-accuracy flotation is less influenced by low-accuracy flotation. The provision of the porous floating part less increases cost than the expansion of the floating suction mixing part 5. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a non-contact support device that supports a workpiece in a non-contact state.

  In the manufacturing process of a liquid crystal panel or the like, there is a process for inspecting the surface of the liquid crystal glass. In this step, the liquid crystal glass is disliked from being placed directly on the support device due to its nature, and a non-contact support device for supporting the liquid crystal glass in a non-contact state is used. Some non-contact support devices have been devised to obtain a certain flying height in order to facilitate focusing of an inspection camera that performs surface inspection (Patent Document 1).

  FIG. 7 shows a conventional non-contact support device 51 that obtains such a constant flying height. The non-contact support device 51 includes a static pressure bearing member 52 and a pair of floating tables 53 provided on both sides thereof. The static pressure bearing member 52 includes a negative pressure unit 54 and a pair of static pressure units 55 provided on both sides thereof. The negative pressure unit 54 is formed with a negative pressure groove 56 on which a suction force acts, and the static pressure unit 55 is provided with a porous body 57 from which air is ejected from the upper surface. On the other hand, each levitation table 53 is formed with a large number of ejection holes 58 which are fine holes through which air is ejected.

  In the non-contact support device 51 configured as described above, the glass substrate G first moves in a state of floating from the upper surface of the floating table 53. When the static pressure bearing member 52 is provided in the region (static pressure bearing region), the air blown from the upper surface of the porous body 57 forms an air film between the two, resulting in static pressure. . At the same time, air suction force acts on the glass substrate G in the negative pressure groove 56. Then, from the harmony between the static pressure and the suction force, the static pressure floating rigidity with respect to the glass substrate G can be increased and the flying height can be made constant in the static pressure bearing region. That is, high-precision levitation is performed in this region.

  By the way, as described above, the levitation table 53 is provided adjacent to the hydrostatic bearing area where the levitation is performed with high accuracy. In this levitation table 53, air is merely ejected from the ejection hole 58, which is a simple pore, so that the levitation in that region is unstable and the levitation amount is not constant, that is, the levitation is low precision. Yes. For this reason, in the conventional non-contact support apparatus 51, it can be said that the area | region where the gap of the floating precision of a low precision levitation and a high precision levitation is large is provided adjacently.

In such a conventional non-contact support device 51, the unstable levitation state in the low accuracy region affects the levitation in the high accuracy region, and the effect that should be originally obtained in the high accuracy levitation region, That is, there is a problem that the effect of increasing the static pressure floating rigidity and making the flying height constant cannot be obtained sufficiently.
JP 2004-152941 A

  In order to cope with the above problem, it is conceivable to widen a highly accurate flying region. However, this causes a problem of increasing the cost.

  Therefore, a main object of the present invention is to provide a non-contact support device capable of reliably obtaining the original effect in a highly accurate flying region while suppressing a significant increase in cost.

  Hereinafter, effective means and the like for solving the above-described problems will be described with reference to actions, effects, and more specific means as required. In the following, in order to facilitate understanding, the corresponding configuration in the embodiment of the invention is appropriately shown in parentheses, but is not limited to the specific configuration shown in parentheses.

Means 1. The surface on the workpiece support side is provided with a plurality of adjacent floating regions that support the workpiece (glass substrate G) in a state where the workpiece (glass substrate G) is floated from the surface by pressurized gas (air), and the floating amount is constant in each floating region. The levitation areas are divided so that each levitation area has a high accuracy levitation area (area where the levitation suction mixing unit 5 is provided) and a low accuracy levitation area (the levitation table 3 has a lower accuracy). In the non-contact support device in which the low-precision floating area is arranged on both sides of the high-precision floating area,
A non-precision floating area (an area in which the porous floating portion 4 is provided) having an intermediate accuracy between both high precision floating areas is provided between the high precision floating area and the low precision floating area. Contact support device.

  According to the means 1, since the high-accuracy flying region is limited to a part of the range, an increase in cost is suppressed accordingly. Further, by providing the medium-accuracy levitation region, it is possible to reduce the levitation accuracy gap in which the levitation amount is constant between the levitation in the high-accuracy levitation region and the levitation on both sides thereof. Thereby, the influence which the levitation | floating in a high precision levitation | floating area receives from the levitation | floating of the lower precision is also reduced. In addition, providing a medium-precision floating area can reduce the cost increase more than expanding the high-precision area. As a result, it is possible to reliably obtain the originally intended high-accuracy levitation while suppressing a significant increase in cost. In addition, as an arrangement configuration of each floating area, more specifically, a medium-precision area is arranged on both sides of the high-precision floating area along the workpiece conveyance direction, and a low-precision area is arranged on the outside thereof. .

Mean 2. It is composed of a static pressure generating part (porous body 23) for ejecting pressurized gas (air) and a suction part (negative pressure groove 33), and a static pressure generated by the static pressure generating part and a suction force generated by the suction part. In a non-contact support device provided with a floating suction mixing unit that causes the workpiece to float by acting on the workpiece (glass substrate G) at the same time,
At least two floating parts (the floating table 3 and the porous floating part 4) that float the work in a state in which the floating amount is lower than that of the floating suction mixing part on both sides along the workpiece conveyance direction of the floating suction mixing part. The non-contact support device is characterized in that the floating accuracy is relatively higher in each floating portion as it is closer to the floating suction mixing portion.

  According to the means 2, the levitation suction mixing unit, which is more accurate than the levitation at the two levitation parts, is limited to a part of the range, so that an increase in cost is suppressed accordingly. Moreover, the accuracy which makes floating amount constant is so high that it is close to a mixing part among at least two floating parts provided in the both sides of the floating suction mixing part. For this reason, the gap of the floating accuracy can be reduced by the floating at the floating suction mixing unit that floats the workpiece with the highest accuracy and the floating by the floating portions on both sides thereof. As a result, the influence of high-accuracy levitation in the levitation suction mixing unit from levitation with lower accuracy is also reduced. Providing at least two floating parts can suppress the increase in cost lower than expanding the high precision region. As a result, it is possible to reliably obtain the originally intended high-accuracy levitation while suppressing a significant increase in cost.

Means 3. A static pressure generating section (porous body 23) for ejecting pressurized gas (air) and a suction section (negative pressure groove 33); a static pressure generated by the static pressure generating section and a suction force generated by the suction section; Levitation suction mixing unit that causes the workpiece to float by simultaneously acting on the workpiece (glass substrate G),
A pair of porous floating parts that are arranged adjacent to both sides of the floating suction mixing unit, generate a static pressure by ejecting pressurized gas from the porous body, and float the workpiece by the static pressure,
A pair of simple floating portions (floating tables 3) that are disposed adjacent to the porous floating portion on the side opposite to the floating suction mixing portion and cause the workpiece to float by ejecting pressurized gas from the ejection holes. A non-contact support device.

  According to the means 3, the levitating accuracy for keeping the floating amount of the workpiece constant is relatively highest in the levitating suction mixing portion, and decreases in order of the porous levitating portion and the simple levitating portion. First, in the levitation suction mixing section, the static pressure levitation rigidity is increased by the harmony between the suction force and the separation force due to the static pressure, and the levitation amount becomes substantially constant. In that respect, it can be said that it is highly accurate. And since the levitation suction mixing part in which high-precision levitation is performed is limited to a part of the range, an increase in cost is suppressed. On the other hand, in the simple floating part, only the pressurized gas is ejected from the ejection hole, and the floating amount there is not constant. In that respect, it can be said that the accuracy is low. Since the pressurized gas is uniformly ejected from the upper surface of the porous body at the porous floating part, the generated static pressure acts uniformly on the workpiece. For this reason, the accuracy of making the flying height constant is higher than that of floating at the simple floating part. In that respect, it can be said to be medium accuracy.

  In addition, a medium-precision porous floating part is provided on both sides (both sides in the conveying direction) of the floating suction mixing part that floats with high accuracy, instead of a low-precision simple floating part. For this reason, the gap of the floating accuracy can be reduced by the floating in the floating suction mixing unit that floats the workpiece with high accuracy and the floating on both sides thereof. Thereby, the influence which the highly accurate levitation | floating in a levitation suction mixing part receives from the levitation | floating of a lower precision is also reduced. Further, providing a simple floating part and a porous floating part can suppress the cost increase lower than expanding the floating suction mixing part.

  As a result, it is possible to reliably obtain the originally intended high-accuracy levitation while suppressing a significant increase in cost.

  Means 4. The non-contact support apparatus according to means 3, wherein the porous floating part is configured by combining a plurality of porous units.

  According to the means 4, the porous floating part can be changed to various sizes by appropriately changing the number of the porous units. For this reason, it can respond to the apparatus of various sizes, and versatility increases.

  Means 5. The non-contact indicating device according to any one of means 1 to 4, wherein a floating amount in the high-precision region or the floating suction mixing unit is set to be larger than a floating amount in another region. .

  According to the means 5, the influence by the difference between the floating amount of the workpiece in the high accuracy region or the floating suction mixing portion and the floating amount in the middle / low accuracy region, or the porous floating portion and the simple floating portion is reduced. Desired high-accuracy levitation can be obtained more easily. According to the means 1 to 4, the influence due to the difference in the stability of the flying height can be reduced, but together with this, it becomes easier to obtain the highly accurate flying that was originally desired.

  Here, the non-contact indication device described in the means 5 preferably includes the following configuration. That is, a pressure adjusting means (electropneumatic regulator 43) for adjusting a pressurized gas supplied to a location constituting a medium-accuracy floating region, a floating portion adjacent to the floating suction mixing portion or a porous floating portion to a set pressure, and a workpiece From the time when the tip of the head is introduced into the high-precision levitation region or the region of the levitation suction mixing unit until it covers the entire upper surface (at the time of introduction), and the rear end begins to pass through the region of the high-precision levitation region or levitation suction mixing unit The pressure adjusting means so as to lift the workpiece in the high-precision floating area or the floating suction mixing section to the set floating amount in the high-precision floating area or the floating suction mixing section until it is completely removed (at the time of derivation). Control means (controller 44) for controlling the set pressure.

  According to this configuration, the control unit controls the set pressure of the pressure adjusting unit, so that the leading end portion or the rear end portion of the workpiece is set in the high-precision floating region or the floating suction mixing unit at the time of introduction / derivation. Can be lifted up to the flying height. Then, at the time of introduction / derivation, even if the floating action in the high-accuracy floating region or the floating suction mixing unit is not sufficient, the leading end portion or the rear end portion of the workpiece floats to the set flying height. Thereby, when a workpiece | work passes over the high precision floating area | region or the floating suction mixing part, the displacement of a floating amount can be decreased through the whole from the front-end | tip to a rear end.

  Further, the control by the control means is specifically performed as follows. First, a set pressure in which the flying height is smaller than that of the floating suction mixing unit is set as a normal set pressure (pressure Pa). At the timing (t1) when the tip of the workpiece is introduced into the area of the levitation suction mixing unit, the set pressure is increased from the normal set pressure so that the levitation amount of the tip increases to the set levitation amount in the mixing unit (pressure Pb), and then gradually lower until the entire upper surface of the levitation suction mixing unit is covered (until timing t2) to the normal set pressure. While the workpiece covers the entire upper surface of the floating suction mixing unit, the normal set pressure is maintained. At the timing (t3) when the rear end of the workpiece starts to escape from the area of the levitation suction mixing portion, the set pressure starts to be gradually increased from the normal setting pressure, and then when the workpiece is completely removed from the levitation suction mixing portion (timing t4). The set pressure is set so that the flying height at the rear end increases to the set flying height at the mixing section (referred to as pressure Pb).

  Hereinafter, an embodiment embodying the present invention will be described with reference to the drawings. In the present embodiment, the case where the non-contact support device is used in a workpiece surface inspection device is embodied. 1 is a plan view showing a non-contact support device, FIG. 2 is a cross-sectional view taken along line AA in FIG. 1, and FIG. 3 is a cross-sectional view taken along line BB in FIG.

  As shown in FIGS. 1 to 3, the non-contact support device 1 includes a base 2 that supports each member described later, and the base 2 is supported by legs (not shown). On the base 2, a pair of floating tables 3, a pair of porous floating portions 4, and a floating suction mixing unit 5 are provided and fixed to the base 2 by appropriate fixing means. In each of these members, first, the porous floating portion 4 is disposed on both sides of the floating suction mixing unit 5, and the floating table 3 is further disposed on the outside thereof.

  The levitation table 3 as a simple levitation portion is provided with a concave portion 11 on the lower surface (joint surface with the base 2) over almost the entire area. For this reason, a pair of internal spaces 12 are formed by the recess 11 of each floating table 3 and the upper surface of the base 2. The internal space 12 is supplied with air as pressurized gas through a port and a passage (not shown) provided in the base 2. A seal is applied between the upper surface of the base 2 and the lower surface of each floating table 3 by, for example, a metal seal.

  In addition, each floating table 3 is formed with an ejection hole 13 that opens on the upper surface and communicates the internal space 12 with the outside. A large number of ejection holes 13 are formed in a lattice shape over the entire region where the recesses 11 are formed. The air supplied to the internal space 12 is ejected from the ejection hole 13. In addition, although the ejection hole 13 is illustrated in an enlarged manner, it is actually formed as a pore.

  Here, each floating table 3 is formed of a metal material that is easy to obtain and process, such as aluminum. Thereby, since formation of the said recessed part 11 and the said ejection hole 13 becomes easy, the floating table 3 can be manufactured cheaply.

  Next, the porous floating part 4 is composed of a number of porous units 21. And in each porous floating part 4, a plurality of porous units 21 are juxtaposed so as to form a row along the transport direction of the glass substrate G as a workpiece, and the row is the width of the glass substrate G (the transport direction). Are arranged side by side in accordance with the width in the direction orthogonal to the vertical direction. In the present embodiment, four rows composed of two porous units 21 are provided. The porous unit 21 includes a unit main body 22 and a porous body 23 fixed to the base 2. An accommodation groove 24 is formed on the upper surface of the unit body 22, and the porous body 23 is accommodated in the accommodation groove 24 so as to form the same plane on both upper surfaces. In addition, you may accommodate so that the upper surface of the porous body 23 may protrude a little. A flow groove 25 is formed on the bottom surface of the housing groove 24. Then, air is supplied into the flow groove 25 through a flow path (not shown) provided in the base 2 and an air passage 26 provided in the unit main body 22.

  On the other hand, the porous body 23 is made of a fluororesin such as a sintered trifluoride resin or a sintered tetrafluoride resin. When air is supplied to the flow groove 25, the air passes through the fine holes of the porous body 23 and is ejected from the upper surface. The porous body 23 may be made of a synthetic resin material such as sintered nylon resin or sintered polyacetal resin, a metal material such as sintered aluminum, sintered copper or sintered stainless steel, sintered carbon, It may be formed of sintered ceramics.

  Next, the levitation suction mixing unit 5 includes a large number of porous units 31 and suction units 32. And these many units 31 and 32 are arrange | positioned so that it may not mutually adjoin, and each is being fixed to the base 2. As shown in FIG. About the porous unit 31, it is the structure similar to the porous unit 21 which comprises the porous floating part 4 mentioned above. For this reason, description is abbreviate | omitted and the code | symbol which shows each component is attached | subjected the same code | symbol as the previous porous unit 21. FIG. On the other hand, the suction unit 32 has a negative pressure groove 33 formed on the upper surface thereof. The negative pressure groove 33 is connected to a suction port (not shown) through a suction passage 34 and a suction passage (not shown) provided in the base 2. For this reason, when a suction force acts on the suction port by evacuation or the like, the suction force acts around the opening of the negative pressure groove 33.

  In the non-contact support device 1 configured as described above, the glass substrate G is held in a non-contact manner as follows. The glass substrate G is transported by transport means (not shown) and moves above the apparatus 1. Further, the glass substrate G is transported while being supported in contact with a portion that is not required to be non-contact, for example, both ends in the width direction.

  First, in each floating table 3, air is supplied to the internal space 12 and ejected from the ejection holes 13. Thereby, a positive pressure is generated between the upper surface of the floating table 3 and the glass substrate G, whereby the substrate G is held in a non-contact state. However, this positive pressure is only generated by air ejection from the ejection holes 13 which are simple pores, and the ascent in the area where the levitation table 3 is provided is the most ascending compared to the levitation in other areas. The amount is not constant and stable. Therefore, levitation in this area can be said to be low-accuracy levitation compared to levitation in other areas.

  Next, in each porous floating portion 4, air is supplied to the air passage 26 of the unit body 22, and air is ejected from the upper surface of the porous body 23. Thereby, a static pressure is generated between the upper surface of the porous body 23 and the glass substrate G, whereby the substrate G is held in a non-contact state. Since air is uniformly ejected from the upper surface of the porous body 23, the static pressure generated at this time acts equally on the glass substrate G. Since the glass substrate G is levitated by such a static pressure, the levitating amount is more stable than the low-precision levitating by the levitating table 3 described above. Therefore, the levitation in the region where the porous levitation portion 4 is provided can be said to be a medium-accuracy levitation in comparison with the levitation in other regions.

  Next, in the levitation suction mixing unit 5, air is supplied to the passage 26 provided in the unit main body 22 of the porous unit 31, and air is ejected from the upper surface of the porous body 23. Thereby, a static pressure is generated between the upper surface of the porous body 23 and the glass substrate G, whereby the substrate G is held in a non-contact state. At the same time, a suction force is applied to the suction passage 34 of the negative pressure unit 32. Then, the negative pressure groove 33 becomes negative pressure. Thereby, a suction force acts on the periphery of the opening portion of the negative pressure groove 33, and the glass substrate G is attracted to the upper surface of the floating suction mixing unit 5. Due to the harmony between this attracting force (suction force) and the force (separation force) that causes the glass substrate G to move away from the upper surface of the floating suction mixing unit 5 by the static pressure generated between the porous body 23 described above, The static pressure levitation rigidity is increased between the levitation suction mixing unit 5 and the substrate G. In the levitation suction mixing unit 5, the glass substrate G is held in a non-contact manner by the static pressure bearing with increased rigidity. As a result, the glass substrate G floats with a substantially constant flying height with respect to the upper surface of the floating suction mixing unit 5 and becomes stable floating. Therefore, it can be said that the levitation in the region where the levitation suction mixing unit 5 is provided is more accurate than the levitation in the two regions described above in that the levitation amount is substantially constant.

  The non-contact support device 1 is arranged in parallel with the floating table 3, the porous floating part 4, the floating suction mixing part 5, the porous floating part 4, and the floating table 3 in this order from the conveyance direction end. . For this reason, the glass substrate G reaches high-precision levitation sequentially through low-precision levitation and medium-precision levitation, and then is sent out through medium-precision levitation and low-precision levitation. An inspection camera CA is installed above the floating suction mixing unit 5 (see FIG. 4), and the surface of the glass substrate G that floats with high accuracy is inspected by the inspection camera CA. In a highly accurate flying state, the flying height is substantially constant, and the camera CA can be easily focused, so that surface inspection can be performed reliably.

  In the present embodiment, the floating table 3 is provided on both sides of the levitation suction mixing unit 5 for levitating the glass substrate G with high accuracy, and is levitated with low accuracy on both sides thereof. It is set as the structure which provided. That is, the areas where the flying accuracy of the glass substrate G is extremely different are not provided adjacent to each other, but are provided with an area where the flying precision is intermediate between them. For this reason, the gap of the floating accuracy is reduced by the high-precision floating in the floating suction mixing unit 5 and the floating in the regions on both sides thereof. As a result, the influence of high-accuracy levitation in the levitation suction mixing unit 5 from levitation with lower accuracy is reduced, and the originally intended high-accuracy levitation can be reliably obtained.

  Here, if the flying height at the porous floating portion 4 and the floating table 3 is set to be approximately the same as or larger than the floating height at the floating suction mixing unit 5, the floating in these regions gives high-precision floating. The influence becomes large, and it becomes difficult to obtain the highly accurate levitation that was originally desired. Therefore, in the non-contact support device 1, the flying height at the floating suction mixing unit 5 is usually set to be larger than the flying height at the porous floating portion 4 and the floating table 3. In this case, the levitation suction mixing unit 5 is set by adjusting the number and arrangement of the porous units 31 and the negative pressure units 32, the air supply pressure, and the like. Moreover, regarding the porous floating part 4 and the floating table 3, it sets by adjusting the air pressure supplied to each. This is the normal control state.

  However, if the normal control state is maintained even during the introduction / extraction to the levitation suction mixing unit 5 during the conveyance of the glass substrate G, the following problems occur. That is, at the time of introduction / derivation, the separation force and the suction force are insufficient for the glass substrate G in the region of the levitation suction mixing unit 5, so the levitation amount is larger than the set levitation amount in the levitation suction mixing unit 5. Get smaller. The flying height is smaller as it is introduced and immediately before derivation. The closer to the state where all the upper surfaces of the floating suction mixing unit 5 are covered (during high-precision flying), the closer to the set flying height and the higher the flying height. For this reason, the displacement of the floating amount in the floating suction mixing unit 5 becomes large at the time of introduction / derivation (see FIG. 6, and FIG. 6 will be described later). For example, as a test result, a difference of 180 μm is generated. In this case, focusing becomes difficult at the front end portion and the rear end portion of the glass substrate G passing under the inspection camera CA at the time of introduction / derivation, and inspection with the inspection camera CA cannot be performed sufficiently.

  Specifically, the time of introduction refers to a period from when the conveyance direction tip of the glass substrate G is introduced into the region of the floating suction mixing unit 5 until the upper surface of the mixing unit 5 is completely covered by the glass substrate G. In addition, the time of derivation refers to a period from when the rear end of the glass substrate G in the transport direction starts to escape from the region of the floating suction mixing unit 5 until it completely exits.

  Therefore, in the non-contact support device 1 of the present embodiment, the porous unit 21 of the porous floating part 4 is designed to reduce the flying height displacement of the glass substrate G in the region of the floating suction mixing unit 5 at the time of introduction / derivation. It is comprised so that the supply pressure of the air ejected from may be controlled.

  First, the specific configuration will be described based on the circuit diagram of FIG. In FIG. 4, for easy understanding, the floating suction mixing unit 5 is indicated by shading, and the porous floating portion 4 is indicated by white. Further, the air supply path to the levitation suction mixing unit 5 is omitted.

  As shown in FIG. 4, an electropneumatic regulator 43 as a pressure adjusting means is provided between each pipe 41 connected to the supply port to both porous floating parts 4 and the air supply source 42. The electropneumatic regulator 43 controls the output side pressure to a set pressure based on a command signal from the controller 44 as a control means. Then, the air having the set pressure is supplied to the porous floating portion 4.

  Further, a substrate detection sensor S is provided above the boundary between the porous floating portion 4 and the floating suction mixing portion 5. The substrate detection sensor S is connected to the controller 44 (not shown). When the substrate detection sensor S detects the presence of the glass substrate G, a substrate detection signal is input to the controller 44. When a signal from the introduction side substrate detection sensor S-1 is input, the controller 44 determines that the tip of the glass substrate G has entered the region of the floating suction mixing unit 5 (timing t1). Further, when a signal from the substrate detection sensor S-2 on the derivation side is also input, the controller 44 determines that the entire upper surface of the floating suction mixing unit 5 is covered with the substrate G (timing t2). Thereafter, when there is no signal input from the substrate detection sensor S-1 on the introduction side, the controller 44 determines that the rear end of the glass substrate G has started to come out of the floating suction mixing unit 5 (timing t3). Then, when there is no signal input from the substrate detection sensor S-2 on the derivation side, the controller 44 determines that the rear end of the glass substrate G is completely removed from the levitation suction mixing unit 5 (timing t4).

  Next, specific pressure control by the controller 44 will be described based on the pressure fluctuation time chart shown in FIG.

  First, the controller 44 is electropneumatic so that the supply pressure to each porous floating portion 4 becomes the pressure Pa in the normal control state until the tip in the transport direction of the glass substrate G enters the region of the floating suction mixing unit 5. A command signal is output to the regulator 43. Thereafter, the movement of the glass substrate G proceeds, and at the timing t1 when the tip enters the region of the floating suction mixing unit 5, the controller 44 outputs a command signal to the electropneumatic regulator 43 so as to increase the supply pressure to the pressure Pb. Here, the floating amount in the floating suction mixing unit 5 is maintained in the normal control state. The pressure Pb is a pressure necessary for lifting the tip portion of the glass substrate G existing in the levitation suction mixing unit 5 to the set levitation amount in the mixing unit 5. It is preset from the relationship with the quantity.

  As the glass substrate G moves from the timing t1 and the upper surface of the levitation suction mixing unit 5 is sequentially covered, the effects of the separation force and the suction force also increase sequentially. For this reason, the controller 44 adjusts the electropneumatic regulator 43-so that the supply pressure is gradually lowered to the pressure Pa in the normal control state until the timing t 2 when the upper surface of the levitation suction mixing unit 5 is entirely covered with the glass substrate G. 1 outputs a command signal. Thereafter, the supply pressure is maintained at the pressure Pa until the timing t3 when the rear end of the glass substrate G starts to escape from the region of the levitation suction mixing unit 5.

  At the timing of t3, the controller 44 outputs a command signal to the electropneumatic regulator 43-2 in order to increase the supply pressure to the porous floating part 4-2 on the outlet side from the pressure Pa in the normal control state. Then, the pressure is gradually increased so that the pressure Pb is reached again at the timing t4 when the glass substrate G is completely removed from the region of the floating suction mixing unit 5.

  Thereafter, when the glass substrate G is completely removed from the region of the levitation suction mixing unit 5, the controller 44 sends a command signal to the electropneumatic regulator 43 so as to return the supply pressure from the pressure Pb to the pressure Pa in the normal control state. Output. And whenever glass substrate G is newly conveyed, control of the supply pressure mentioned above is performed repeatedly.

  FIG. 6 is a schematic diagram showing how the substrate G floats at the time of introduction / derivation and at high precision. As in FIG. 4, the floating suction mixing unit 5 is indicated by shading, and the porous floating portion 4 is indicated by white. Moreover, the area division | segmentation by a virtual line is also a typical thing.

  As shown in FIGS. 6 (a) and 6 (b), the tip of the glass substrate G in the region of the levitation suction mixing unit 5 is controlled by controlling the supply pressure to the porous levitation unit 4 at the time of introduction and derivation. The portion (shown by a solid line) is lifted from a low flying state as shown by a two-dot chain line to a set flying height shown by a one-dot chain line. For this reason, the flying height displacement of the glass substrate G at the time of introduction / derivation becomes small. For example, as a result of a test performed in the same situation as the above-described test (where a displacement of 180 μm occurred), the displacement could be reduced to 70 μm by controlling the supply pressure. In addition, as shown in FIG.6 (c), at the time of high precision levitation, the glass substrate G in the area | region of the levitation suction mixing part 5 is levitated by the set levitation amount. For this reason, when the glass substrate G passes above the levitation suction mixing unit 5, the displacement of the levitation amount decreases from the front end to the rear end.

  As described above in detail, the present embodiment has the following excellent effects.

  On both sides of the levitation suction mixing unit 5 that levitates with high accuracy, medium-precision porous levitation portions 4 are provided instead of the low-accuracy levitation table 3. For this reason, it is possible to reduce the influence of the high-accuracy levitation from the levitation adjacent thereto, and to reliably obtain the originally intended high-accuracy levitation. Moreover, since the supply pressure to the porous levitation portion 4 is adjusted to suppress the displacement of the levitation amount at the time of introduction / derivation to the levitation suction mixing unit 5, the displacement of the levitation amount is small from the front end to the rear end. Thereby, the focusing by the inspection camera CA is facilitated from the front end to the rear end of the glass substrate G passing therebelow, and the inspection by the inspection camera CA can be reliably performed.

  Thereby, it is not necessary to provide the whole non-contact support device 1 with a structure for obtaining high-precision levitation such as the levitation suction mixing unit 5. In the first place, the levitation suction mixing unit 5 allows a high static pressure levitation rigidity to be obtained by causing a large amount of air to be ejected from the porous body 23 and simultaneously exerting a suction force, and makes the levitation amount constant. For this reason, it is expensive in terms of the composite of the porous unit 31 and the negative pressure unit 32, and the running cost is also expensive in that a large amount of air is consumed. Compared with that, if it is the structure which provided only the floating suction mixing part 5 like this Embodiment, both the manufacturing cost and the running cost can be reduced significantly. Moreover, the inconvenience of limiting high-precision levitation to a part by the above-described configuration and control of supply pressure is sufficiently eliminated. Therefore, the required high-accuracy levitation can be reliably obtained while greatly suppressing an increase in cost.

  In addition, embodiment is not limited to said content, For example, you may implement as follows.

  In the above embodiment, as the porous unit 31 constituting the levitation suction mixing unit 5, those having two kinds of planar shapes as shown in FIG. 1 are used, but the planes of the porous unit 31 and the negative pressure unit 32 are used. All shapes may be unified. Further, the planar shape of the porous body 23 and the negative pressure groove 33 is not limited to a circular shape, and may be other shapes such as an oval shape. Furthermore, the number and arrangement of the porous units 31 and the negative pressure units 32 are not limited to those shown in FIG. 1, and may be appropriately changed depending on the weight of the glass substrate G, the required flying height, and other factors. .

  In the above embodiment, the porous unit 21 constituting the porous floating portion 4 has a different planar shape from the porous unit 31 constituting the floating suction mixing unit 5, but both may be unified. Further, the planar shape of the porous body 23 is not limited to a circular shape. Further, the porous floating part 4 may be constituted by one member instead of being constituted by a large number of porous units 21.

  In the above embodiment, the pressure Pb for increasing the supply pressure of the porous floating part 4 at the time of introduction / derivation is set in advance. However, the glass substrate G can be obtained by a laser displacement meter or the like provided above the porous floating part 4. It is good also as a structure which detects the flying height of this and performs feedback control which makes the flying height in the floating suction mixing part 5 the target value.

  In the above embodiment, the glass substrate G is taken as an example of the workpiece, but the glass substrate G is not limited as long as it is a thin plate.

  In the said embodiment, although air was mentioned as an example as a pressurized gas supplied to the non-contact support apparatus 1, other gases, such as nitrogen, may be used besides air.

The top view which shows a non-contact support apparatus. AA sectional view taken on the line AA of FIG. FIG. 3 is a sectional view taken along line BB in FIG. 1. The circuit explanatory view showing the supply route of the air to the porous floating part. The time chart which shows the pressure fluctuation of the air supplied to a porous floating part. The schematic diagram which showed the mode that the glass substrate floated. The top view which shows the conventional non-contact support apparatus.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Non-contact support apparatus, 3 ... Levitation table as simple floating part, 4 ... Porous floating part, 5 ... Levitation suction mixing part, 23 ... Porous body, 33 ... Negative pressure groove, 43 ... As pressure adjustment means Electropneumatic regulator, 44... Controller as control means.

Claims (5)

The work support side surface is equipped with a plurality of flotation areas that support the work piece in a state where it is lifted from the surface by pressurized gas, and each flotation area is configured to have a different accuracy to keep the flotation amount constant. In the non-contact support device in which each levitation region is divided into a high accuracy levitation region with relatively high accuracy and a low accuracy levitation region with low accuracy, and the low accuracy levitation regions are arranged on both sides of the high accuracy levitation region,
A non-contact support device, wherein a medium-accuracy levitation region having an intermediate accuracy between both the high-accuracy levitation regions and the low-accuracy levitation regions is provided. A floating suction mixing system that consists of a static pressure generating part that ejects pressurized gas and a suction part, and that causes the static pressure generated by the static pressure generating part and the suction force generated by the suction part to act on the work at the same time. In the non-contact support device provided with a portion,
At least two levitation parts are provided on both sides of the levitation suction mixing unit along the workpiece conveyance direction so that the workpiece is levitated with a lower accuracy than that of the levitation suction mixing unit. A non-contact support device characterized in that the levitation accuracy is relatively higher as it is closer to the suction mixing unit. A floating suction mixing unit that has a static pressure generating unit and a suction unit for ejecting pressurized gas, and causes the workpiece to float by causing the static pressure generated by the static pressure generating unit and the suction force generated by the suction unit to simultaneously act on the workpiece. When,
A pair of porous floating parts that are arranged adjacent to both sides of the floating suction mixing unit, generate a static pressure by ejecting pressurized gas from the porous body, and float the workpiece by the static pressure,
The porous levitation unit is disposed adjacent to the levitation suction mixing unit on the side opposite to the levitation suction mixing unit, and includes a pair of simple levitation units for ejecting pressurized gas from the ejection holes to float the workpiece. Non-contact support device.   The non-contact support device according to claim 3, wherein the porous floating portion is configured by combining a plurality of porous units.   The non-contact instruction according to any one of claims 1 to 4, wherein a flying height in the high-precision area or the floating suction mixing unit is set to be larger than a flying height in another area. apparatus.

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