JP5223615B2 - Method and apparatus for detecting floating conveyance state of thin plate - Google Patents

Description

  The present invention relates to a method and an apparatus for detecting a transport state of a thin plate such as a semiconductor substrate or a liquid crystal substrate that is levitated from a transport surface and transported in a transport direction.

  For example, a thin glass plate used for a semiconductor substrate or a liquid crystal substrate is transported by being lifted from the transport surface by air blown from the transport surface to the lower surface in order to prevent scratching during the transport. Therefore, when starting operation of equipment for floating and transporting a thin plate, it is important to confirm beforehand that the thin plate after transport is not actually damaged by contact with the transport surface.

  Confirmation that the thin plate after conveyance is not scratched can, of course, be performed by directly checking the thin plate after conveyance. However, it is difficult to inline by automation. Further, the work for visually confirming the presence or absence of scratches requires a great amount of labor, whether it is human or image processing.

In order to reduce this labor, there is a proposal for electrically detecting contact of the thin plate with the conveying surface. In this proposal, a conductive film is formed on each of the conveyance surface and the lower surface of the thin plate facing the conveyance surface, and electrical conduction between the two films due to contact between both surfaces is detected. In addition, the location of the thin plate which contacted the conveyance surface can also be specified by dividing | segmenting into a plurality the conductive film of the lower surface of a thin plate (for example, patent document 1).
JP 2007-768336 A

  However, in the above proposal, it is necessary to form a conductive film on the conveyance surface and the lower surface of the thin plate, respectively. Therefore, considerable effort is required in advance preparation (pretreatment), and there is still room for improvement. Yes.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to detect the transport state of a thin plate that is lifted from the transport surface and transported in the transport direction without requiring complicated preparation in advance. Another object of the present invention is to provide a method for detecting a floating conveyance state of a thin plate suitable for in-line by automation and an apparatus therefor.

In order to achieve the above object, the method for detecting a floating conveyance state of a thin plate according to the present invention described in claim 1 is a method for detecting a conveyance state of a thin plate that is lifted from a conveyance surface and conveyed in a conveyance direction, At least a part of the thin plate conveyance path is photographed by a plurality of cameras fixedly spaced apart from each other by a predetermined distance, and each image data of the area photographed simultaneously by the cameras passes through the area. A position in a floating direction of the thin plate with respect to the transport surface in the area of the thin plate being transported from a pixel position of a plurality of points set to at least a part of the thin plate and a position of each camera. 3D relative position detects, based on the temporal change of position of the thin in the transport direction of the three-dimensional relative in position the detection of sheet in the conveying comprising There are, and detects the actual conveying speed in the conveying direction of the sheet in the conveyance in the area. Note that the plurality of points may be set in a random arrangement as long as they are distributed to a certain degree of uniform density, or may be positively set in a matrix arrangement at equal intervals.

In order to achieve the above object, the thin plate levitation conveyance state detection device according to the present invention described in claim 4 is a device that detects the conveyance state of the thin plate that is levitated from the conveyance surface and conveyed in the conveyance direction. A plurality of cameras that are fixedly spaced apart from each other and that respectively photograph at least a part of the transport path of the thin plate, and the areas in the image data of the areas that are simultaneously photographed by the cameras. Position in the floating direction of the thin plate with respect to the transport surface in the area of the thin plate being transported from the pixel positions of a plurality of points set in at least a part of the thin plate passing through and the position of each camera and the thin position detecting means for detecting a three-dimensional relative positions including, in 3-dimensional relative position of the thin plate in said conveying analyzed by the thin position analyzing means Based on the temporal change of position of the thin in the conveying direction, characterized in that it comprises the real transport speed detecting means for detecting an actual transport speed in the transport direction of the sheet in the conveyance in the area. Note that the plurality of points may be set in a random arrangement as long as they are distributed to a certain degree of uniform density, or may be positively set in a matrix arrangement at equal intervals.

  According to the method for detecting the floating conveyance state of the thin plate of the present invention described in claim 1 and the apparatus for detecting the floating conveyance state of the thin plate of the present invention described in claim 5, each camera is at least a part of the conveyance path of the thin plate. Shoot each of the areas. Then, the pixel positions of a plurality of points set on the thin plate passing through the area in the image data of the area photographed simultaneously by the cameras are different. The difference in the pixel position of each point is caused by the presence of parallax in each camera that captures the same area from a position spaced apart from each other by a predetermined distance.

Since each camera and transport surface are fixed and their positions are known, by analyzing the difference in pixel position on the pixel data of each point due to the parallax of each camera and the known position of each camera The three-dimensional relative position of each point with respect to the conveyance surface can be obtained. Further, from the three-dimensional relative position of each point, the three-dimensional relative position with respect to the transport surface of the thin plate portion between the points can be obtained by interpolation. Thus, it is possible to detect the three-dimensional relative position including against the conveying surface of the thin plate passing through the area taken by the plurality of cameras, a position in floating direction of the sheet.

Then, based on the detected three-dimensional relative position including the position in the floating direction of the thin plate with respect to the conveying surface of the thin plate, the posture of the thin plate that is levitated from the conveying surface and conveyed in the conveying direction is grasped, and the thin plate is lifted detects a transport state, Ru can be determined by automatically inline whether in good condition. In addition, due to the temporal change of the position of the thin plate in the transport direction in the three-dimensional relative position with respect to the detected transport surface of the thin plate, it is not the transport speed set for the propulsive force in the transport direction applied to the thin plate from the transport surface side. The actual conveyance speed of the thin plate actually conveyed by the driving force can be detected. Thereby, the transmission efficiency of the propulsive force with respect to the floated thin plate can be verified, and the result can be used for fine adjustment of the equipment for improving the transmission efficiency.
Further, the method of detecting the floating conveyance state of the thin plate of the present invention described in claim 2 is the method of detecting the floating conveyance state of the thin plate of the present invention described in claim 1, wherein the analyzed three-dimensional relative of the thin plate being conveyed The presence or absence of meandering with respect to the ideal transport locus of the thin plate being transported in the area based on the temporal change in the position of the thin plate in the width direction of the thin plate perpendicular to the transport direction and the flying direction in the position It is characterized by detecting the quantity.
In addition, the thin plate levitation conveyance state detection device of the present invention described in claim 5 is the thin plate levitation conveyance state detection device of the present invention described in claim 4, wherein the thin plate position analysis means analyzes the medium. Based on the time-dependent change of the position of the thin plate in the width direction of the thin plate orthogonal to the transport direction and the floating direction in the three-dimensional relative position of the thin plate, the ideal transport locus of the thin plate being transported in the area Meandering detection means for detecting the presence or absence of meandering or the amount of meandering.
According to the method for detecting the floating conveyance state of the thin plate of the present invention described in claim 2, the method for detecting the floating conveyance state of the thin plate of the present invention described in claim 1, and also the thin plate of the present invention described in claim 5, According to the levitation conveyance state detection device of claim 4, in the levitation conveyance state detection device for a thin plate of the present invention described in claim 4, both of the conveyance direction and the levitation direction in a three-dimensional relative position with respect to the detected conveyance surface of the thin plate The conveyance trajectory of the thin plate being conveyed can be obtained by a change with time of the position of the thin plate in the width direction of the orthogonal thin plates. Then, it is possible to detect whether or not the obtained transport path of the thin plate meanders with respect to the ideal transport path, or the amount of meander when the meander path is meandered with respect to the ideal transport path. .

Further, the method for detecting a floating conveyance state of a thin plate of the present invention described in claim 3 is the method for detecting a floating conveyance state of a thin plate of the present invention described in claim 1 or 2 , wherein the analyzed 3 of the thin plate being conveyed is analyzed. Detecting, based on the position of the thin plate in the floating direction in a dimension relative position, whether or not the thin plate being transported in the area is in contact with the transport surface where the position in the floating direction is fixed. Features.

A thin plate floating conveyance state detection device according to the present invention described in claim 6 is the thin plate floating conveyance state detection device according to claim 4 or 5 , wherein the thin plate floating conveyance state detection device is analyzed by the thin plate position analyzing means. Based on the position of the thin plate in the floating direction in the three-dimensional relative position of the thin plate being conveyed, the presence or absence of contact with the conveyance surface of the thin plate being conveyed in the area is fixed in the floating direction It is further characterized by further comprising contact detection means for detecting the location.

According to the method for detecting a floating conveyance state of a thin plate of the present invention described in claim 3 , the method for detecting a floating conveyance state of a thin plate of the present invention described in claim 1 or 2 , and the present invention described in claim 6. According to the apparatus for detecting the levitation conveyance state of the thin plate, the levitation conveyance state detection apparatus for the thin plate of the present invention according to claim 4 or 5 , wherein the levitation direction in the three-dimensional relative position with respect to the detected conveyance surface of the thin plate The presence or absence of contact of the thin plate with respect to the conveyance surface can be detected by determining whether the position of the thin plate overlaps with the position of the fixed conveyance surface. Or, depending on which part of the thin plate the position of the thin plate in the floating direction in the three-dimensional relative position with respect to the detected conveyance surface of the thin plate and the position of the conveyance surface where the position in the floating direction is fixed overlap. The contact location with respect to the surface can be detected.

  In this way, it is determined whether or not the thin plate is being lifted and transported accurately, or if it is not performed accurately, the position is specified, and this is useful for maintenance to be performed accurately. Can do.

According to levitation transportation state detecting method and apparatus for thin plate of the present invention, the position in the flying direction of the thin plates against the conveying surface of the fixed thin plate, and detects the three-dimensional relative positions including the position in the floating direction of the sheet Thus, the posture of the thin plate that is levitated from the conveyance surface and conveyed in the conveyance direction is grasped, the floating conveyance state of the thin plate is detected, and whether or not it is in a good state automatically Judgment can be made inline.

  DESCRIPTION OF EMBODIMENTS Hereinafter, a thin plate floating conveyance state detection apparatus according to an embodiment of the present invention to which a thin plate floating conveyance state detection method according to the present invention is applied will be described with reference to the drawings.

  First, about a schematic configuration of a levitation conveyance apparatus in which the thin plate levitation conveyance state detection apparatus according to the present embodiment is used, a principal part enlarged plan view of FIG. 6, a side view of FIG. 7, and a principal part enlarged sectional view of FIG. It will be briefly described with reference to the above.

  The levitation conveyance device indicated by reference numeral 10 in FIG. 6 is for levitating a glass thin plate W used for a semiconductor substrate or a liquid crystal substrate and conveying it in the conveyance direction X. The levitation transport apparatus 10 includes a support base B, a pair of transport units 11 and 11 disposed on the support base B at an interval in a width direction Y orthogonal to the transport direction X of the thin plate W being transported, A plurality of chambers 25 arranged in the conveyance direction X between the conveyance units 11 and 11 of the table B, and a plurality of floating units 37 respectively arranged in a matrix in a standing manner in each chamber 25. Yes.

  Each transport unit 11 includes a plurality of transport rollers 13 arranged at equal intervals in the transport direction X, a transport motor 23 that rotationally drives each transport roller 13, and power that transmits the power of the transport motor 23 to each transport roller 13. And a transmission mechanism 15. The power transmission mechanism 15 includes a plurality of worm wheels 17 that rotate integrally with the transport rollers 13, a plurality of worms 21 that mesh with the worm wheels 17, and a drive shaft 19 to which these worms 21 are attached. ing. The drive shaft 19 is connected to the output shaft of the transport motor 23.

  As shown in FIG. 7, both edges in the width direction Y of the thin plate W transported in the transport direction X by the floating transport device 10 are respectively placed on the transport rollers 13 of the transport units 11. When the transport motor 23 of each transport unit 11 is driven, each transport roller 13 is rotated in the same direction by the power transmitted by the power transmission mechanism 15. Thereby, the thin plate W mounted on each conveyance roller 13 is conveyed in the conveyance direction X shown in FIG.

  As shown in FIG. 8, each chamber 25 is formed in a hollow shape and has a plurality of intake ports 27. A fan 31 is attached to each intake port 27 by a bracket 33, and air is sent from each fan 31 into the chamber 25.

  Each levitation unit 37 has a levitation unit leg 43 erected from the chamber 25 and a levitation unit body 39 attached to the upper part of the levitation unit leg 43. The interior of each floating unit 37 is formed hollow. The interior of each floating unit 37 communicates with the interior of the chamber 25 through a through hole 29 formed in the chamber 25. Further, as shown in FIG. 6, slits 41 are respectively formed on the upper surface of each floating unit main body 39. Air is sent into each levitation unit 37 from the chamber 25 through the through hole 29. The air that has been sent in is ejected from the above-described slit 41 toward the top of each floating unit 37.

  The thin plate W transported in the transport direction X by each transport unit 11 described above is transported on the transport surface S of the thin plate W by the upper surface of each levitation unit body 39 by the air jetted upward from each levitation unit 37 (see FIG. 8). Emerge from. This levitation acts so as to reduce the load of the thin plate W applied to each transport roller 13 as much as possible within a range that does not impair the contact between each transport roller 13 of each transport unit 11 and the thin plate W. Thereby, the thin plate W is efficiently conveyed in the conveyance direction X by the rotational force transmitted from each conveyance roller 13 without the center in the width direction Y being bent downward by its own weight.

  Note that reference numeral 35 in FIG. 6 is an opening existing between the chambers 25 adjacent in the transport direction X. Each opening 35 communicates with the installation surface of the levitation conveyance apparatus 10, and the air for levitation is not ejected from the opening 35. Therefore, the thin plate W transported in the transport direction X by the transport unit 11, when straddling each opening 35, and each floating unit 37 erected in the chamber 25 located on the upstream side of the transport direction X, and the transport direction X Ascending by the air ejected from both of the levitation units 37 provided upright in the chamber 25 located on the downstream side.

  Next, a thin plate levitation conveyance state detection device according to an embodiment of the present invention that detects the state of the thin plate W that is levitation conveyance by the above-described levitation conveyance device 10 will be described. FIG. 1 is an explanatory diagram schematically showing a schematic configuration of a levitation conveyance state detection apparatus according to an embodiment of the present invention, and FIG. 2 is an electrical outline of the levitation conveyance state detection apparatus according to an embodiment of the present invention. It is a block diagram which shows a structure.

  The floating conveyance state detection apparatus of the present embodiment indicated by reference numeral 1 in FIG. 1 analyzes two cameras 3L and 3R arranged above the floating conveyance apparatus 10 and images taken by these cameras 3L and 3R. And a controller 5 (see FIG. 2).

  The cameras 3L and 3R are respectively attached to an arch-shaped frame 7 disposed across the levitation conveyance device 10, and both the cameras 3L and 3R are disposed at a predetermined interval in the width direction Y. Yes. In the present embodiment, each of the cameras 3L and 3R is configured by a digital camera. From each of the cameras 3L and 3R, image data for one frame of a photographed image converted into an electrical signal by an individual image sensor incorporated therein is periodically output.

  The shooting range of each camera 3L, 3R is set in a partial area A that is common to the transport path of the thin plate W that is transported in the transport direction X by the levitation transport device 10, as indicated by the phantom line in FIG. Yes. However, since the cameras 3L and 3R capture the area A from different positions with a predetermined interval in the width direction Y, the image data of the area A captured by the respective cameras 3L and 3R includes both parallaxes. The pixel position on the frame differs depending on

  When the controller 5 analyzes the image data of the area A photographed by the cameras 3L and 3R described above to detect the floating conveyance state of the thin plate W, since the thin plate W is a transparent glass substrate, the controller 5 In order to facilitate the image processing in the above, a plurality of markers 9 with equal intervals in the transport direction X and the width direction Y are attached to the thin plate W.

  As shown in FIG. 2, the controller 5 includes a CPU 5a, a RAM 5b, and a ROM 5c. In addition to the RAM 5b and ROM 5c, cameras 3L and 3R are connected to the CPU 5a. The RAM 5b has a data area for storing various data and a work area used for various processing operations. The ROM 5c stores a control program for causing the CPU 5a to perform various processing operations. Then, the CPU 5a analyzes the image data from the cameras 3L and 3R according to the control program stored in the ROM 5c.

  In addition, in the data area of the RAM 5b, the coordinate conversion necessary for calculating the three-dimensional position coordinate values of specific elements in the images photographed by the cameras 3L and 3R from the image data from the cameras 3L and 3R by calculation. Data is stored.

  Further, a frame memory area for storing image data from the cameras 3L and 3R in units of frames is secured in the work area of the RAM 5b. Two frame memory areas may be secured for each of the cameras 3L and 3R. In that case, image data is alternately written in the two frame memory areas. While image data is being written to one frame memory area, analysis is performed in parallel on the previous image data that has already been written to the other frame memory area that is not used for writing image data. Can do.

  Next, an outline of analysis processing of image data from the cameras 3L and 3R, which is executed by the CPU 5a of the controller 5 according to a program stored in the ROM 5c, will be described with reference to flowcharts of FIGS.

  When the controller 5 is activated by turning on the power, the CPU 5a, as shown in the flowchart of FIG. 3, captures image data from the cameras 3L and 3R (step S1) and analyzes the captured image data. (Step S3), the position detection process (Step S5) of the thin plate W based on the analysis result, and the floating conveyance state detection process (Step S7) of the thin plate W based on the detected position of the thin plate W are periodically performed. Run.

  Among these, in the image data capturing process in step S1, the CPU 5a stores two pieces of image data from the cameras 3L and 3R in the RAM 5b corresponding to the cameras 3L and 3R. Write to either. In the analysis processing in step S3, the CPU 5a performs analysis processing on image data in a frame memory area that is not used for writing image data in step S1.

  FIG. 4 is a flowchart showing detailed contents of the analysis processing executed in step S3 of FIG. In this analysis process, the CPU 5a first extracts markers present in the images of the cameras 3L and 3R based on the image data (step S31). Extraction of a marker in each image can be performed using a known image processing logic such as an edge extraction method or a pattern recognition method. Next, the CPU 5a checks whether or not there are more markers than are necessary for specifying the three-dimensional position of the thin plate W (step S33). When the necessary number of markers or more are not present in each image (NO in step S33), the CPU 5a ends the analysis process.

  On the other hand, if more than the necessary number of markers are present in each image (YES in step S33), the CPU 5a identifies the position of the pixel corresponding to each marker in each image (step S35), and identifies The three-dimensional position coordinate value of each marker is determined from the pixel position of each marker in each image (step S37). The three-dimensional position coordinate value of each marker can be determined by calculation based on the difference in the pixel position of the same marker that occurs between the images due to the parallax of each camera 3L, 3R, and its amount and direction. For this calculation, coordinate calculation data stored in the data area of the RAM 5b is used. Note that the three-dimensional position coordinate value of each marker determined by this calculation may be a coordinate value in the world coordinate system or a coordinate value in the local coordinate system. Thereafter, the CPU 5a ends the analysis process.

  In the position detection process in step S5 of FIG. 3, the CPU 5a determines the three-dimensional position coordinate value (coordinate value) of the lower surface of the thin plate W facing the transport surface S from the three-dimensional position coordinate value of each marker determined in step S35. Group). The three-dimensional position coordinate value (coordinate value group) of the thin plate W is estimated by data interpolation of the three-dimensional position coordinate value (coordinate value group) of the upper surface of the thin plate W existing between two adjacent markers. Detection can be performed by calculating the thickness and surface dimensions of the known thin plate W. Subsequently, the CPU 5a performs the floating conveyance state detection process in step S7 using the three-dimensional position coordinate value (coordinate value group) of the lower surface of the thin plate W detected in step S5.

  FIG. 5 is a flowchart showing detailed contents of the floating conveyance state detection process executed in step S7 of FIG. In this floating conveyance state detection process, first, the CPU 5a first detects the three-dimensional position coordinate value (coordinate value group) of the lower surface of the thin plate W detected in step S5 and the three-dimensional position coordinate value (coordinate value group) of the known conveyance surface S. ), The presence / absence of the lower surface of the thin plate W in contact with the transport surface S and the contact location are detected (step S71). This detection is performed by, for example, comparing the three-dimensional position coordinate value of the lower surface of the thin plate W with the three-dimensional position coordinate value of the conveyance surface S in which the coordinate values in the conveyance direction X and the width direction Y are the same. That is, when the coordinate value in the height direction Z (see FIG. 7) of the lower surface of the thin plate W is equal to or lower than the coordinate value in the height direction Z of the transport surface S to be compared, the thin plate W The lower surface is in contact with the transport surface S.

  Next, the CPU 5a compares the three-dimensional position coordinate value of the lower surface of the thin plate W detected in step S5 with the three-dimensional position coordinate value of the lower surface of the thin plate W previously detected in step S5, thereby comparing the actual conveyance speed of the thin plate W. Is detected (step S73). Specifically, from the amount of change in the coordinate value in the transport direction X among the current and previous three-dimensional position coordinate values of the lower surface of the thin plate W detected in step S5, and the cycle in which the CPU 5a performs the position detection process in step S5. The actual conveyance speed in the conveyance direction X of the thin plate W is detected.

  Subsequently, the CPU 5a compares the three-dimensional position coordinate value of the lower surface of the thin plate W detected in step S5 with the three-dimensional position coordinate value of the lower surface of the thin plate W previously detected in step S5, and the presence / absence and amount of meandering. Is detected (step S75). Specifically, when the coordinate value in the width direction Y of the current and previous three-dimensional position coordinate values of the lower surface of the thin plate W detected in step S5 has changed by a predetermined amount or more, the thin plate W meanders. Can be recognized. Thereafter, the CPU 5a ends the floating conveyance state detection process.

  As described above, in the present embodiment, the plate thickness and surface dimensions of the thin plate W and the three-dimensional position coordinate values (coordinate value group) of the transport surface S are known. Therefore, in the position detection process in step S5 of FIG. 3, detecting the three-dimensional position coordinate value (coordinate value group) of the lower surface of the thin plate W means that the dimensional relative position of the thin plate W with respect to the transport surface S is detected. It will be to. Therefore, in the present embodiment, the position detection process in step S5 in FIG. 3 is a process corresponding to the thin plate position detection means in the claims.

  Further, as is clear from the above description, in the present embodiment, step S71 in FIG. 5 is processing corresponding to the contact detection means in the claims. Furthermore, in this embodiment, step S73 in FIG. 5 is a process corresponding to the actual conveyance speed detection means in the claims. Moreover, in this embodiment, step S75 of FIG. 5 is a process corresponding to the meandering detection means in the claims.

  Next, the operation of the levitation conveyance state detection apparatus 1 of the present embodiment configured as described above will be described. First, when the transport state of the thin plate W transported by the levitation transport device 10 is detected by the levitation transport state detection device 1, the upper surface of the thin plate W is spaced at equal intervals in the transport direction X and the width direction Y. The markers 9 are attached in a matrix. The marker 9 is affixed to the upper surface of the thin plate W because the thin plate W is made of glass and it is difficult to extract its outline on the image data. The marker 9 facilitates extraction of the upper surface of the thin plate W on the image data. And the thin plate W which stuck the marker 9 on the upper surface is conveyed in the conveyance direction X by the levitation conveyance apparatus 10. FIG.

  In the levitated conveyance state detection device 1, when the thin plate W conveyed by the levitating conveyance device 10 and passing through the area A is photographed by the two cameras 3L and 3R, the image analysis is performed by using the presence of the marker 9 as a clue. The three-dimensional position coordinate value (coordinate value group) of the thin plate W is detected. And the position corresponding to the coordinate value of the conveyance direction X and the width direction Y that the coordinate value of the conveyance direction X and the width direction Y is the same value or the value lower than the coordinate value of the height direction Y of the same conveyance surface S , The lower surface of the thin plate W is in contact with the transport surface S.

  Further, the floating conveyance state detection apparatus 1 detects the actual conveyance speed of the thin plate W, the presence / absence of meandering, and the amount of meandering from the change over time of the detected three-dimensional position coordinate value (coordinate value group) of the thin plate W. .

  Note that the levitation conveyance apparatus adjustment process may be performed after the levitation conveyance state detection process in step S7 of FIG. And in this levitation conveyance apparatus adjustment process, the adjustment process of the ejection amount of the air with respect to the thin plate W for the purpose of the contact prevention with respect to the conveyance surface S of the thin plate W can be performed. In this adjustment process, for example, according to the contact location of the thin plate W with respect to the conveyance surface S detected in step S71 of FIG. The process which adjusts the ejection amount of air can be performed per unit 37 unit.

  Further, in the levitation conveyance device adjustment process, it is possible to perform an adjustment process of the amount of air ejected onto the thin plate W for the purpose of improving the conveyance efficiency of the thin plate W in the conveyance direction X by the conveyance unit 11. In this adjustment process, for example, the actual transport speed in the transport direction X of the thin plate W detected in step S73 of FIG. 5 is set for each transport unit 11 in the area A photographed by the cameras 3L and 3R. To the target transport speed in the transport direction X. Then, the amount of air blown to the thin plate W is increased in a range where the actual conveyance speed does not fall below the target conveyance speed by a predetermined value or more.

  Thereby, while maintaining the power transmission efficiency from the transport unit 11 to the transport direction X with respect to the thin plate W, the load applied to the transport unit 11 from the thin plate W is reduced to increase the transport efficiency of the thin plate W in the transport direction X. It can be carried out. In this process, the process of adjusting the air ejection amount can be performed in each chamber 25 unit corresponding to the area A that can be photographed by the cameras 3L and 3R or in each floating unit 37 unit.

  Furthermore, in the levitation conveyance device adjustment process, it is possible to perform an adjustment process of the amount of air blown to the thin plate W for the purpose of suppressing meandering in the width direction Y of the thin plate W conveyed in the conveyance direction X. In this adjustment process, for example, each chamber 25 unit or each floating unit 37 unit so that the meandering is eliminated according to the amount of meandering in the width direction Y of the thin plate W detected in step S75 of FIG. Thus, it is possible to perform a process of adjusting the amount of air ejection.

  The adjustment process of the air ejection amount is performed especially when the thin plate W is transported from the upstream side to the downstream side in the transport direction X across the opening 35 and the downstream of each floating unit 37 in the chamber 25 on the upstream side of the opening 35. It may be useful to do so with each floating unit 37 of the side chamber 25. This is because the amount of air ejected from each levitation unit 37 is not balanced between the upstream side and the downstream side of the opening 35, which causes meandering in the width direction Y of the thin plate W. When it is, it appears prominently.

  As described above, according to the floating conveyance state detection device 1 of the present embodiment, the two cameras 3L and 3R in which the marker 9 attached to the thin plate W conveyed by the floating conveyance device 10 is disposed above the conveyance surface S are provided. Are extracted from the image data of the area A photographed respectively, and the three-dimensional position coordinate value (coordinate value group) of the thin plate W is detected from the three-dimensional position coordinate value to detect the presence or absence of contact with the transport surface S and the contact location. It was set as the structure to do.

  For this reason, it is determined whether or not the levitation conveyance of the thin plate W is accurately performed by the levitation conveyance device 10, or when the levitation conveyance device 10 is not accurately performed, the position thereof is specified so as to be accurately performed. Can be useful for maintenance.

  In the present embodiment, since the thin plate W is a transparent glass substrate, a plurality of markers 9 are attached to the upper surface of the thin plate W at equal intervals in the transport direction X and the width direction Y, respectively. The markers 9 in the images photographed by the cameras 3L and 3R are extracted by image processing. However, if it is possible to extract points at equal intervals in the conveyance direction X and width direction Y of the thin plate W from the images photographed by the cameras 3L and 3R, respectively, the marker 9 may be omitted.

  Further, regardless of whether or not the marker 9 is attached, in the present embodiment, a plurality of points set on the thin plate W are arranged in a matrix shape with equal intervals in the conveyance direction X and the width direction Y of the thin plate W. It was supposed to be. However, a plurality of points may be set on the thin plate W not at regular intervals but in a random arrangement as long as they are distributed at a uniform density that does not hinder the specification of the three-dimensional position of the thin plate W.

  Furthermore, regardless of whether it arrange | positions at equal intervals or arrange | positions at random, in this embodiment, the point was set over the whole upper surface of the thin plate W. FIG. However, when the regularity is recognized in the posture of the thin plate W being conveyed by the levitation conveyance device 10, that is, when the posture of a part of the thin plate W is repeated also in the peripheral region, You may make it set a point only to an area | region.

  Further, in the present embodiment, the case where the floating conveyance state of the thin plate W is detected from the images captured by the two cameras 3L and 3R has been described. However, the floating conveyance state of the thin plate W by the plurality of images captured by the plurality of cameras. It is good also as a structure which detects.

  Further, in the present embodiment, the case where the levitation conveyance device 10 is configured to convey the thin plate W in the conveyance direction X by the conveyance roller 13 is described, but for conveying the thin plate W in the levitation conveyance device 10 in the conveyance direction X. The configuration is not limited to the configuration described in the present embodiment, and may be another configuration.

It is explanatory drawing which shows typically schematic structure of the levitation conveyance state detection apparatus which concerns on one Embodiment of this invention. It is a block diagram which shows the electrical schematic structure of the levitation conveyance state detection apparatus which concerns on one Embodiment of this invention. It is a flowchart which shows the outline of the process which CPU of the controller of FIG. 2 performs according to the control program stored in ROM. It is a flowchart which shows the outline of the process which CPU of the controller of FIG. 2 performs according to the control program stored in ROM. It is a flowchart which shows the outline of the process which CPU of the controller of FIG. 2 performs according to the control program stored in ROM. It is a principal part enlarged plan view which shows schematic structure of the levitation conveyance apparatus in which the levitation conveyance state detection apparatus of the thin plate which concerns on one Embodiment of this invention is used. It is a side view which shows schematic structure of the levitation conveyance apparatus in which the levitation conveyance state detection apparatus of the thin plate which concerns on one Embodiment of this invention is used. It is a principal part expanded sectional view which shows schematic structure of the levitation conveyance apparatus in which the levitation conveyance state detection apparatus of the thin plate which concerns on one Embodiment of this invention is used.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Levitation conveyance state detection apparatus 3L, 3R Camera 5 Controller 5a CPU (Thin plate position detection means, contact detection means, actual conveyance speed detection means, meander detection means)
5b RAM
5c ROM
7 Frame 9 Marker (point)
DESCRIPTION OF SYMBOLS 10 Levitation conveyance apparatus 11 Conveyance unit 13 Conveyance roller 15 Power transmission mechanism 17 Worm wheel 19 Drive shaft 21 Worm 23 Conveyance motor 25 Chamber 27 Intake 29 Through-hole 31 Fan 33 Bracket 35 Opening 37 Levitation unit 39 Levitation unit main body 41 Slit 43 Levitation Unit leg A Area B Support stand S Conveying surface W Thin plate X Conveying direction Y Width direction Z Height direction

Claims (6)

A method for detecting a conveyance state of a thin plate that is levitated from a conveyance surface and conveyed in a conveyance direction,
Photographing at least a part of the transport path of the thin plate with a plurality of cameras fixedly spaced apart from each other by a predetermined distance,
In the image data of each of the areas simultaneously photographed by the respective cameras, the pixel positions of a plurality of points set on at least a part of the thin plate passing through the area and the positions of the respective cameras are being conveyed. Detecting a three-dimensional relative position in the area of the thin plate, including a position in the floating direction of the thin plate with respect to the transport surface ;
Detecting an actual conveyance speed in the conveyance direction of the thin plate in the area based on a change over time of the position of the thin plate in the conveyance direction in the detected three-dimensional relative position of the thin plate in conveyance;
A method for detecting a floating conveyance state of a thin plate. The thin plate being transported in the area based on a change over time of the position of the thin plate in the width direction of the thin plate perpendicular to the transport direction and the flying direction in the detected three-dimensional relative position of the thin plate being transported 2. The method for detecting a floating conveyance state of a thin plate according to claim 1, wherein the presence / absence of the meandering or the amount of meandering with respect to the ideal conveyance trajectory is detected . Based on the position of the thin plate in the floating direction in the detected three-dimensional relative position of the thin plate being conveyed, the position of the thin plate being conveyed in the area is in contact with the conveyance surface where the position in the floating direction is fixed 3. The method for detecting a floating conveyance state of a thin plate according to claim 1 , wherein the presence or absence or the contact location is detected . An apparatus for detecting a conveyance state of a thin plate that is levitated from a conveyance surface and conveyed in a conveyance direction,
A plurality of cameras that are fixedly spaced apart from each other and that respectively image at least a portion of the transport path of the thin plate;
In the image data of each of the areas simultaneously photographed by the respective cameras, the pixel positions of a plurality of points set on at least a part of the thin plate passing through the area and the positions of the respective cameras are being conveyed. A thin plate position detecting means for detecting a three-dimensional relative position including a position in the floating direction of the thin plate with respect to the transport surface in the area of the thin plate;
Based on the change over time of the position of the thin plate in the transport direction in the three-dimensional relative position of the thin plate being transported analyzed by the thin plate position analyzing means, the actual state of the thin plate being transported in the area in the transport direction. An actual conveyance speed detection means for detecting the conveyance speed;
An apparatus for detecting a floating conveyance state of a thin plate, comprising: Based on the time-dependent change in the position of the thin plate in the width direction of the thin plate perpendicular to the transport direction and the flying direction in the three-dimensional relative position of the thin plate being transported analyzed by the thin plate position analyzing means 5. The apparatus for detecting the state of floating of a thin plate according to claim 4, further comprising meandering detecting means for detecting the presence or amount of meandering with respect to an ideal transport trajectory of the thin plate being transported. Based on the position of the thin plate in the floating direction in the three-dimensional relative position of the thin plate being transported analyzed by the thin plate position analyzing means, the position of the thin plate being transported in the area is fixed in the floating direction. 6. The apparatus for detecting a floating conveyance state of a thin plate according to claim 4 , further comprising contact detection means for detecting the presence or absence of contact with the conveyance surface or a contact location.

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