PCB transport device

Abstract

To provide a substrate conveying apparatus which can accurately determine a relative position relation between two detection positions set in each of conveyance paths of a substrate, where presence / absence of the substrate is detected.SOLUTION: A substrate conveying apparatus includes: a first sensor for detecting whether or not a substrate exists at a first position of the conveyance path of the substrate; a second sensor for detecting whether or not the substrate exists at a second position on the downstream side of the first position on the conveyance path; and a first calculation part for conveying the substrate along the conveyance path, allowing one of the first sensor and the second sensor to detect the front end or the rear end of the substrate, then conveying the substrate and allowing the other of the first sensor and the second sensor to detect the front end or the rear end of the substrate, and calculating a first separation distance between the first position and the second position on the basis of the conveyance distance between the two detections where the substrate is conveyed.SELECTED DRAWING: Figure 4

Description

Technical Field

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[0001] This specification relates to a substrate transfer device that transfers a substrate along a transfer path.

Background Art

[0002] Techniques for mass-producing substrate products by performing substrate operations on substrates with circuit patterns formed thereon have become widespread. Generally, a substrate operation machine that performs substrate operations includes a substrate transfer device that performs substrate loading, positioning at a stop position, and unloading. Many substrate transfer devices include sensors for detecting the position of the substrate during transfer, and stop the substrate at a predetermined stop position based on the detection results of the sensors. If the position error of the stop position is large, the substrate transfer device re-transfers the substrate to correct the stop position. This enables the performance of substrate operations. One technical example related to this type of substrate transfer device is disclosed in Patent Document 1.

[0003] The substrate conveyor control device of Patent Document 1 includes a first substrate sensor and a second substrate sensor provided in the transfer path of a substrate conveyor that is rotated by the operation of an electric motor to detect specific portions (front end, rear end) of the substrate, a command unit that commands the operation amount of the electric motor based on the detection result of any one of the substrate sensors, and an estimation unit that estimates the stop position of the substrate based on the elapsed time between the detection of the substrate sensor and the stop of the electric motor, or the operation amount of the electric motor between the detections of the two substrate sensors. According to this, it is said that by detecting the substrate with two substrate sensors, the stop position of the substrate can be estimated at low cost, and the estimation results can be utilized in various ways.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Incidentally, the technical example in Patent Document 1 is preferable in that the stopping position of the substrate can be estimated based on the detection results of the first substrate sensor and the second substrate sensor. However, the first and second substrate sensors used are sensors that detect whether or not the detection light is blocked by the substrate. For this reason, when changing the type of substrate, the detection position may be displaced when changing the position of the sensors or adjusting the detection sensitivity. In other words, positional errors may occur at the first position where the first substrate sensor detects and at the second position where the second substrate sensor detects. If positional errors occur, the accuracy of estimating the stopping position of the substrate will decrease.

[0006] Therefore, the problem to be solved in this specification is to provide a substrate transport device that can accurately determine the relative positional relationship between two detection positions set in the substrate transport path for detecting the presence or absence of a substrate. [Means for solving the problem]

[0007] This specification discloses a substrate transport device comprising: a first sensor for detecting whether or not the substrate is present at a first position in the substrate transport path; a second sensor for detecting whether or not the substrate is present at a second position downstream of the first position in the transport path; and a first calculation unit for transporting the substrate along the transport path, causing one of the first and second sensors to detect the front or rear end of the substrate, then transporting the substrate to cause the other of the first and second sensors to detect the front or rear end of the substrate, and calculating a first separation distance between the first position and the second position based on the transport distance the substrate has been transported between the two detections.

[0008] Furthermore, this specification discloses the technical idea of ​​changing "the substrate transport device described in any one of claims 1 to 4" to "the substrate transport device described in any one of claims 1 to 5" in claim 6 of the original application, the technical idea of ​​changing "the substrate transport device described in claim 1" to "the substrate transport device described in any one of claims 1 to 8" in claim 9 of the original application, and the technical idea of ​​changing "the substrate transport device described in any one of claims 1 to 4 or 9 to 12" to "the substrate transport device described in any one of claims 1 to 12" in claim 15 of the original application. [Effects of the Invention]

[0009] According to the substrate transport apparatus disclosed herein, the first calculation unit transports the substrate and causes the first sensor and the second sensor to detect the front or rear end of the substrate, thereby calculating the first separation distance between the first position and the second position based on the transport distance of the substrate. This makes it possible to accurately determine the first separation distance corresponding to the relative positional relationship between the two detection positions. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic plan view showing the overall configuration of a component mounting machine to which the substrate transport device of this embodiment is applied. [Figure 2] This is a front cross-sectional view of the substrate transport device near its stopping position. [Figure 3] This is a side view of the substrate transport device. [Figure 4] This is a schematic plan view showing the first position, second position, and stop position set for the substrate transport device. [Figure 5] This is a block diagram showing the control configuration for a substrate transport device. [Figure 6] This is a diagram illustrating the main operation flow of the substrate transport device. [Figure 7] This is a sub-operation flow diagram illustrating the details of the operation of the first calculation unit in step S3 of Figure 6. [Figure 8] This is a schematic diagram illustrating the operation of the first calculation unit through the transport of a circuit board. [Figure 9]It is a schematic diagram schematically explaining a modification example of step S16 and step S17 in FIG. 7. [Figure 10] It is a diagram of a sub-operation flow explaining the details of the operation of the second calculation unit in step S4 of FIG. 6. [Figure 11] It is a schematic diagram schematically explaining the operation of the second calculation unit. [Figure 12] It is a diagram of a time chart initially set by the stop position adjustment unit. [Figure 13] It is a schematic diagram showing the position of the substrate corresponding to the time chart of FIG. 12. [Figure 14] It is a diagram of a sub-operation flow explaining the details of the operation of the stop position adjustment unit in step S8 of FIG. 6. [Figure 15] It is a diagram of an adjustment time chart explaining the adjustment operation of the stop position by the stop position adjustment unit. [Figure 16] It is a schematic diagram showing the position of the substrate corresponding to the adjustment time chart of FIG. 15 and schematically explaining the adjustment operation of the stop position. [Figure 17] It is a back view of a measurement jig used in place of the substrate.

Embodiments for Carrying Out the Invention

[0011] 1. Overall Configuration of Component Mounter 1 As an example of a substrate processing machine to which the substrate transfer device 2 of the embodiment is applied, a component mounter 1 is illustrated and described with reference to FIG. 1. The component mounter 1 performs a mounting operation of mounting components on a substrate K. The horizontal direction from the left side to the right side of the paper surface in FIG. 1 is the X-axis direction for transporting the substrate K, the horizontal direction from the lower side (front side) to the upper side (rear side) of the paper surface is the Y-axis direction, and the vertical direction is the Z-axis direction. The component mounter 1 is configured by assembling a substrate transfer device 2, a component supply device 3, a component transfer device 4, and a control device (not shown) etc. on a base 10.

[0012] The substrate transfer device 2 has a pair of guide rails 21 that form the transfer path of the substrate K. The substrate transfer device 2 transfers the substrate K carried into the loading end (the left end in FIG. 1) of the guide rail 21 by a substrate loading device or an external transfer device along the guide rail 21 and transfers it to a predetermined stop position ST. The predetermined stop position ST of the substrate K is set at the center in the transfer direction of the transfer path (see FIG. 4). With respect to the substrate K positioned at the stop position ST, the component mounting operation by the component transfer device 4 is performed. After the mounting operation is completed, the substrate transfer device 2 transfers the said substrate K from the stop position ST to the unloading end (the right end in FIG. 1) and unloads it outside the machine. The substrate transfer device 2 will be described in detail later.

[0013] The component supply device 3 is arranged at the front part in the Y-axis direction on the upper surface of the base 10. The component supply device 3 is composed of a plurality of tape feeders 31 arranged side by side in the X-axis direction. Each of the plurality of tape feeders 31 feeds out a carrier tape in which a large number of components are stored in a row toward the supply position 32 on the tip side. The carrier tape supplies the components so that they can be picked up at the supply position 32.

[0014] The component transfer device 4 is composed of a Y-axis moving body 41, an X-axis moving body 42, a mounting head 43, a rotary tool 44, a plurality of suction nozzles 45, a substrate camera 46, and a component camera 47, etc. The Y-axis moving body 41 is formed of a member long in the X-axis direction and is driven by a Y-axis drive mechanism to move in the Y-axis direction. The X-axis moving body 42 is mounted on the Y-axis moving body 41 and is driven by an X-axis drive mechanism to move in the X-axis direction. The mounting head 43 is attached to the front surface of the X-axis moving body 42. The mounting head 43 is driven in two horizontal directions together with the X-axis moving body 42 and moves above the component supply device 3 and above the substrate K. Using the X-Y coordinate system representing the position of the mounting head 43 (or the X-axis moving body 42), the predetermined stop position ST in the substrate transfer device 2 is set.

[0015] A rotary tool 44 is rotatably mounted below the mounting head 43. The rotary tool 44 rotates around a vertical central axis, driven by an R-axis drive mechanism (not shown). The rotary tool 44 has multiple (12 in the example in Figure 1) suction nozzles 45 equidistant from the vertical central axis. The suction nozzles 45 move up and down, driven by a lifting drive mechanism (not shown), and rotate around a vertical axis, driven by a Q-axis drive mechanism (not shown). The suction nozzles 45 are further selectively supplied with negative pressure air and positive pressure air from an air supply mechanism. As a result, the suction nozzles 45 perform a suction process to pick up parts from the parts supply device 3 and a mounting process to mount the parts onto the substrate K. Note that the mounting head 43 may omit the rotary tool 44 and have multiple suction nozzles 45 arranged in a line or in a grid.

[0016] The substrate camera 46 is mounted facing downwards on the X-axis moving body 42, alongside the mounting head 43. The substrate camera 46 captures a position reference mark attached to the substrate K from above. The acquired image data is processed to accurately determine the stopping position of the substrate K. The component camera 47 is mounted facing upwards on the base 10 between the substrate transport device 2 and the component supply device 3. The component camera 47 captures and recognizes components held by the suction nozzle 45 from below while the mounting head 43 is moving from the component supply device 3 to the substrate K. This determines whether the component is correct or incorrect, and also detects the position and orientation of the component relative to the suction nozzle 45, which is then reflected in the mounting process. Examples of substrate cameras 46 and component cameras 47 include digital imaging devices having image sensors such as CCD (Charge Coupled Device) and CMOS (Complementary Metal Oxide Semiconductor).

[0017] The control device, not shown in the figure, is mounted on the base 10, and its placement is not particularly limited. The control device is composed of a computer. The control device may also be composed of multiple CPUs distributed within the machine and connected via communication. Based on mounting work data created for each type of substrate K, the control device controls the substrate transport device 2, the component supply device 3, and the component transfer device 4 to proceed with the component mounting work. The mounting work data is data describing information such as the type of substrate K, the type of component and mounting coordinate position, information such as the tape feeder 31 and suction nozzle 45 to be used, and detailed procedures for the mounting work.

[0018] 2. Configuration of the substrate transport device 2 Next, the configuration of the substrate transport device 2 of the embodiment will be explained with reference to Figures 2 to 4. The transport direction (forward direction) of the substrate K is from the front side to the back side of the paper in Figure 2, and from left to right in Figure 3. The substrate transport device 2 consists of the aforementioned pair of guide rails 21, a pair of conveyor belts 22, a pulse motor 23, a clamping device 24, a first sensor 51, a second sensor 52, a third sensor 53, and a transport control unit 8 (see Figure 5).

[0019] As shown in Figures 2 and 3, a pair of support plates 29 are provided on the upper surface of the base 10, standing upright and positioned parallel to each other at a distance. Guide rails 21 are provided on the upper side of each of the support plates 29. The pair of guide rails 21 constitute the transport path for the substrate K. The distance between the pair of guide rails 21 is set to correspond to the width dimension of the substrate K. This distance can be adjusted variably by sliding one of the support plates 29 along the upper surface of the base 10.

[0020] A belt guide 211 extending in the transport direction is positioned on the inner sides of a pair of opposing guide rails 21. An endless annular conveyor belt 22 is provided so as to be guided along each guide rail 21 and onto the upper surface of the belt guide 211. Two sides of the substrate K, along the transport direction, are placed on the upper surface of the conveyor belt 22. The conveyor belt 22 is one embodiment of a moving member that moves along the transport path (guide rails 21) while holding the substrate K and allowing it to slide in the transport direction.

[0021] As shown in Figure 2, the conveyor belt 22 is engaged with a pair of front and rear transport guide pulleys 222, a pair of front and rear return pulleys 223, a direction changing pulley 224, a drive pulley 225, and a tensioning pulley 226. The tensioning pulley 226 applies tension to the conveyor belt 22 to prevent slack. The drive pulley 225 is supported so as to rotate integrally with the spline shaft 227. The spline shaft 227 extends perpendicular to the transport direction and is fixed to the center of each of the pair of drive pulleys 225. The spline shaft 227 is rotationally driven by a pulse motor 23 via a gear mechanism. The pulse motor 23 is one embodiment of a transport drive unit that moves the moving member (conveyor belt 22).

[0022] The pulse motor 23 is controlled by input drive pulses, which rotates the spline shaft 227, causing the pair of conveyor belts 22 to rotate via the pair of drive pulleys 225. As a result, the pair of conveyor belts 22 rotate (move) synchronously, holding the substrate K on their upper surface and transporting it. The substrate K is simply placed on the conveyor belts 22 and is not locked in place. Therefore, the substrate K may slide (move relative to) the conveyor belts 22 in the transport direction if the acceleration or deceleration of the conveyor belts 22 is large when they move. Note that the sliding of the substrate K can also be caused by factors other than acceleration and deceleration, such as vertical movement during transport or the momentum when it is brought into the input end from the outside.

[0023] The pulse motor 23 rotates forward by a predetermined angle upon input of a positive pulse (a drive pulse of positive polarity) and reverses by a predetermined angle upon input of a negative pulse (a drive pulse of negative polarity). The forward or reverse rotation of the pulse motor 23 by a predetermined angle causes the conveyor belt 22 to rotate in the forward or reverse direction by a predetermined unit distance. The number of positive and negative pulses input to the pulse motor 23 is counted by the pulse counter 84 (see Figure 5). By multiplying the effective pulse count, obtained by subtracting the number of negative pulses from the number of positive pulses, by the unit distance, the amount of rotation of the conveyor belt 22 in the forward direction, i.e., the distance traveled in the forward direction, can be determined. Furthermore, the distance traveled by the conveyor belt 22 during a certain period can be determined based on the change in the effective pulse count during that period. A positive change in the effective pulse count indicates that the substrate K was transported in the forward direction, and a negative change indicates that the substrate K was transported in the reverse direction.

[0024] The clamping device 24 is positioned below the stop position ST. The clamping device 24 consists of a plurality of support pins 241, a base 242, a plurality of pilot bars 243, and a fluid pressure cylinder 244. The plurality of support pins 241 are mounted upright on the upper surface of the rectangular plate-shaped base 242. The number and arrangement of the plurality of support pins 241 are adjusted as appropriate according to the type of substrate K to be transported. The base 242 is supported and guided so as to be vertically movable by the plurality of pilot bars 243. The base 242 is driven to move up and down by the fluid pressure cylinder 244.

[0025] The clamping device 24 operates after the substrate K has been transported to near the stop position ST and has come to a stop. In detail, the fluid pressure cylinder 244 raises the base 242. The support pins 241, which rise together with the base 242, push the substrate K upward (see the dashed line in Figure 2). The substrate K is clamped and positioned at a height KK between the retaining portion 218, which extends inward from the top of the guide rail 21, and the support pins 241 (clamping operation). After the component mounting work by the component transfer device 4 is completed, the fluid pressure cylinder 244 lowers the base 242, releasing the clamped state of the substrate K (release operation). As a result, the substrate K is placed back on the conveyor belt 22, making it possible to transport it to the end of the conveyor belt and to remove it from the machine.

[0026] As shown in Figures 3 and 4, the first sensor 51 is positioned so that the upstream input end of the conveying path where the conveyor belt 22 performs its conveying function is the target detection position. The second sensor 52 is positioned so that the stopping position ST set in the center of the conveying path is the target detection position. The third sensor 53 is positioned so that the downstream output end of the conveying path is the target detection position. The first sensor 51, the second sensor 52, and the third sensor 53 detect whether or not a substrate K is present at their respective detection positions. The first sensor 51, the second sensor 52, and the third sensor 53 have the same configuration and consist of a light-emitting unit 6 and a light-receiving unit 7, etc.

[0027] As shown in Figures 2 and 4, the light-emitting unit 6 is provided on one guide rail 21, and the light-receiving unit 7 is provided on the other guide rail 21. The light-emitting unit 6 emits detection light LD in a generally horizontal direction toward the light-receiving unit 7, and the light-receiving unit 7 receives the detection light LD. The detection light LD is preferably one with a stable diameter and excellent straight-line propagation. When the detection light LD is blocked by the substrate K, the light-receiving unit 7 does not receive the detection light LD, and at this time detects the presence of the substrate K. The light-receiving unit 7 outputs an ON signal during the blocking period when the substrate K is detected, and an OFF signal during the receiving period when the substrate K is not detected.

[0028] Therefore, the point of change from an ON signal to an OFF signal signifies the end of the passage of the substrate K during transport. On the other hand, the point of change from an OFF signal to an ON signal signifies the start of the entry of the substrate K during transport. As can be seen from the above explanation, it is possible to detect the front end KF and rear end KR of the substrate K based on the point of change of the output signals of the first sensor 51, the second sensor 52, and the third sensor 53, as well as the transport direction of the substrate K (forward or reverse).

[0029] The first sensor 51, the second sensor 52, and the third sensor 53 are each mounted to target the desired detection position, but in reality, positional errors may occur in the mounting positions. Also, during setup changes when changing the type of substrate K, when one of the support plates 29 and guide rails 21 is slid to accommodate differences in the width dimension of the substrate K, the light-emitting unit 6 or the light-receiving unit 7 moves along with it. As a result, the light-emitting unit 6 or the light-receiving unit 7 may be displaced in the transport direction. Furthermore, the light beam of the detection light LD of the light-emitting unit 6 or the light-receiving sensitivity of the light-receiving unit 7 may be adjusted to accommodate differences in the thickness of the substrate K before and after setup changes, or the presence or absence of components mounted on the front end KF or rear end KR of the substrate K. In this case, the detection position may shift even if the sensor does not move.

[0030] In other words, the first position P1, which corresponds to the detection position of the first sensor 51, is set at the input end of the transport path with a position error to be tolerated. The second position P2, which corresponds to the detection position of the second sensor 52, is set at the stop position ST of the transport path with a position error to be tolerated. The third position P3, which corresponds to the detection position of the third sensor 53, is set at the output end of the transport path with a position error to be tolerated. To make the following explanation easier to understand, the position error between the second position P2 and the stop position ST is exaggerated in Figures 4, 8, 9, 11, 13, and 16. Note that the stop position ST is the position where the center KM of the transport direction of the substrate K is stopped. The first sensor 51 and the second sensor 52 may be mounted to target different target detection positions than those described above. In this embodiment, the upstream detection position closer to the input end becomes the first position P1, and the downstream detection position closer to the stop position ST becomes the second position P2.

[0031] In the conventional technology, the transport control unit 8 controlled the transport of the substrate K by assuming that the first position P1 coincided with the loading end and the second position P2 coincided with the stopping position ST, without considering the positional error described above. As a result, when the substrate camera 46 confirmed the actual stopping position of the substrate K, there were cases where the actual stopping position was not within the allowable error range (e.g., ±1 mm) from the predetermined stopping position ST, or the frequency of such cases was increasing. In such cases, it became necessary to release the clamping device 24, re-transport the substrate K closer to the stopping position ST, re-clamp the clamping device 24, and re-imaging the substrate camera 46. This resulted in a significant decrease in the production efficiency of the component mounting machine 1.

[0032] 3. Configuration related to the control of the substrate transport device 2 In this embodiment, as a countermeasure to the above-mentioned problems, the transport control unit 8 is provided with a first calculation unit 81, a second calculation unit 82, and a stop position adjustment unit 83. This countermeasure can be implemented by updating the software and does not require any hardware changes. Therefore, this countermeasure can be easily applied not only to newly manufactured component mounting machines 1 but also to component mounting machines 1 that have already been delivered to users. The configuration of the control of the substrate transport device 2 will be described below with reference to Figure 5.

[0033] The conveying control unit 8 is configured using a computer device with a CPU that operates using software. The conveying control unit 8 receives output signals from the first sensor 51, the second sensor 52, and the third sensor 53. The conveying control unit 8 also controls the clamping and releasing operations of the clamping device 24. Furthermore, the conveying control unit 8 controls the direction of movement, acceleration, speed, and deceleration of the conveyor belt 22 by controlling the positive and negative polarity and time interval (frequency of occurrence) of the drive pulses input to the pulse motor 23. The conveying control unit 8 controls the direction of movement, acceleration, speed, and deceleration of the conveyor belt 22. The low-speed movement speed VL used by the first calculation unit 81 and the normal movement speed VH used by the stop position adjustment unit 83 are used interchangeably as the movement speed of the conveyor belt 22. The normal movement speed VH is set to the maximum movement speed corresponding to the rated output state of the pulse motor 23. Alternatively, the normal movement speed VH is set between the low-speed movement speed VL and the maximum movement speed.

[0034] At the low-speed travel speed VL, the acceleration and deceleration before and after the speed can be made relatively small, so the slippage of the substrate K in the transport direction is less likely to occur compared to transporting the substrate K at the normal travel speed VH. The first calculation unit 81 can improve the accuracy of calculating the first separation distance D1 by using the low-speed travel speed VL (described later). On the other hand, at the normal travel speed VH, the acceleration and deceleration before and after the speed are relatively large, so there is a possibility of slippage of the substrate K in the transport direction. Nevertheless, the stop position adjustment unit 83 improves transport efficiency by shortening the transport time required to transport the substrate K by using the normal travel speed VH.

[0035] The transport control unit 8 is directly connected to the transfer control unit 9 via communication, or indirectly connected via the aforementioned control device or other parts. The transfer control unit 9 controls the mounting operation of the component transfer device 4. Specifically, the transfer control unit 9 controls the movement of the Y-axis moving body 41 and the X-axis moving body 42 to control the position of the mounting head 43. The transfer control unit 9 also controls the operation of the R-axis drive mechanism, lifting drive mechanism, Q-axis drive mechanism, and air supply mechanism. Furthermore, the transfer control unit 9 controls the imaging operation of the substrate camera 46 and component camera 47.

[0036] The transfer control unit 9 includes an image processing unit 91 that processes image data acquired by the substrate camera 46. A typical image processing unit 91 detects the position of the position reference mark of the substrate K in the image data to detect the stopping position of the substrate K. In this embodiment, the image processing unit 91 is further equipped with the function of detecting the position of the edges of the front end KF and rear end KR of the substrate K in the image data to detect the stopping position of the substrate K. The second calculation unit 82 of the transport control unit 8 utilizes parts of the component transfer device 4 and the transfer control unit 9 (described later).

[0037] The first calculation unit 81, the second calculation unit 82, and the stop position adjustment unit 83 are configured using software from the computer device that constitutes the transport control unit 8. The substrate transport device 2 is capable of both forward operation, which transports the substrate K from the input end to the stop position ST, and reverse operation, which transports the substrate K from the output end to the stop position ST. The following description will focus on the case where the first sensor 51 and the second sensor 52 are used in forward operation. For reverse operation, the first sensor 51 and the first position P1 in the following description can be read as the third sensor 53 and the third position P3, and the front end KF and rear end KR of the substrate K can be read as the same, and the forward and reverse directions of the transport path can be reversed.

[0038] The first calculation unit 81 first transports the substrate K along the transport path and causes one of the first sensor 51 and the second sensor 52 to detect the front end KF or rear end KR of the substrate K. The first calculation unit 81 then transports the substrate K and causes the other of the first sensor 51 and the second sensor 52 to detect the front end KF or rear end KR of the substrate K. Next, the first calculation unit 81 calculates the first separation distance D1 (see Figures 8 and 9) between the first position P1 and the second position P2 based on the transport distance the substrate K has traveled between the two detection points.

[0039] As described above, the order of detection by the first sensor 51 and the second sensor 52 does not matter; either sensor can be used first. Also, the transport direction of the substrate K between the two detections can be either forward or reverse. Furthermore, the detection targets for the two detections can be any of the following: (1) detecting the front end KF of the substrate K twice, (2) detecting the rear end KR of the substrate K twice, (3) detecting the front end KF of the substrate K followed by the rear end KR, or (4) detecting the rear end KR of the substrate K followed by the front end KF.

[0040] The first calculation unit 81 controls the pulse motor 23 to move the conveyor belt 22 and transport the substrate K, and determines the transport distance of the substrate K based on the distance the conveyor belt 22 moves between the two detections. More specifically, in this embodiment, the first calculation unit 81 uses a low-speed VL that is less likely to cause slippage of the substrate K than the normal-speed VH. The first calculation unit 81 determines the distance the conveyor belt 22 moves by multiplying the change in the effective number of drive pulses input to the pulse motor 23 between the two detections by a unit distance. Furthermore, the first calculation unit 81 can use the distance the conveyor belt 22 moves as the transport distance of the substrate K. In this way, by using a low-speed VL that is less likely to cause slippage of the substrate K than the normal-speed VH, the transport distance of the substrate K can be determined accurately and easily.

[0041] The specific method by which the first calculation unit 81 calculates the first separation distance D1 varies depending on which of (1) to (4) the detection target is. In cases (1) and (2), the first calculation unit 81 can use the transport distance of the substrate K as the first separation distance D1. In cases (3) and (4), the first calculation unit 81 calculates the first separation distance D1 by adding or subtracting the length dimension LK of the substrate K in the transport direction to the transport distance of the substrate K. The transport control unit 8 may acquire information on the length dimension LK in advance, or it may measure the length dimension LK using the substrate K. In the case of measurement, the transport control unit 8, for example, transports the substrate K in the forward direction using a low-speed VL, and calculates the length dimension LK by multiplying the number of positive pulses input to the pulse motor 23 from the time the second sensor 52 detects the front end KF until it detects the rear end KR by a unit distance.

[0042] Meanwhile, the second calculation unit 82 controls a detection unit capable of detecting the substrate K located in the transport path to detect the position of the substrate K when the second sensor 52 detects the front end KF or rear end KR of the substrate K. Furthermore, based on the detection result, the second calculation unit 82 calculates a second separation distance D2 (see Figure 11) between a predetermined stop position ST and the second position P2. As described above, when the second sensor 52 detects the front end KF or rear end KR of the substrate K, the front end KF or rear end KR is stopped at the second position P2. The second calculation unit 82 indirectly detects the second position P2 by detecting the position of the substrate K using an imaging device consisting of a substrate camera 46 and an image processing unit 91 as the detection unit.

[0043] Specifically, the second calculation unit 82, in cooperation with the transfer control unit 9, controls the substrate camera 46 to move to the desired position and perform an imaging operation of the substrate K to acquire image data. This image data is processed by the image processing unit 91 to determine the position of the front end KF or rear end KR of the substrate K, i.e., the second position P2. This image processing is performed using the XY coordinate system of the component transfer device 4. On the other hand, the stop position ST is set using the same XY coordinate system. Therefore, the second calculation unit 82 can accurately calculate the second separation distance D2. The second separation distance D2 can be a positive value (the second position P2 is upstream of the stop position ST), zero, or a negative value (the second position P2 is downstream of the stop position ST).

[0044] The transport control unit 8 controls the pulse motor 23 based on the calculated first separation distance D1 and second separation distance D2 to move the conveyor belt 22 and stop the substrate K at the stop position ST. The stopping position of the substrate K is adjusted by the stop position adjustment unit 83. In order to ensure high transport efficiency, the stop position adjustment unit 83 controls the transport of the substrate K in the forward direction using the normal travel speed VH and, in principle, does not control the transport of the substrate K in the reverse direction.

[0045] The stop position adjustment unit 83 transports the substrate K in the forward direction and determines the actual travel distance Mrl of the conveyor belt 22 required from the time the first sensor 51 detects the rear end KR of the substrate K until the second sensor 52 detects the front end KF of the substrate K. Specifically, the stop position adjustment unit 83 calculates the actual travel distance Mrl by multiplying the number of positive pulses input to the pulse motor 23 between the two detections by a unit distance. Next, the stop position adjustment unit 83 calculates the theoretical travel distance Mth by subtracting the length dimension LK of the substrate K in the transport direction from the first separation distance D1. Then, the stop position adjustment unit 83 calculates the difference distance △M between the actual travel distance Mrl and the theoretical travel distance Mth (see Figure 16). In this embodiment, the stop position adjustment unit 83 uses a clock 85 that measures time and elapsed time to calculate the difference distance △M in a different way than described above (described later).

[0046] The difference distance △M corresponds to the amount of slip (relative movement) of the substrate K in the transport direction. Therefore, it is possible to estimate the degree of slip of the substrate K based on the difference distance △M. For example, the slip ratio can be calculated by dividing the difference distance △M by the actual movement distance Mrl.

[0047] The stop position adjustment unit 83 adjusts the travel distance MR of the conveyor belt 22 after the second sensor 52 detects the front end KF of the substrate K, based on the difference distance ΔM. The specific method for adjusting the travel distance MR is changed according to the detailed structure and operating characteristics of the substrate transport device 2, as well as its compatibility with the substrate K. For example, the stop position adjustment unit 83 adjusts the travel distance MR assuming that the slip rate described above will continue to occur at roughly the same rate thereafter.

[0048] Generally, the component mounting machine 1 repeats the mounting operation on multiple identical circuit boards K. The first calculation unit 81 and the second calculation unit 82 can accurately calculate the first separation distance D1 and the second separation distance D2 by operating on the first circuit board K. The stop position adjustment unit 83 can improve the positional accuracy of the stopping position where the circuit board K actually stops by using the calculated first separation distance D1 and second separation distance D2 for the second and subsequent circuit boards K. The first calculation unit 81, the second calculation unit 82, and the stop position adjustment unit 83 will be described further in the following operation description.

[0049] 4. Operation of the substrate transport device 2 Next, the operation of the substrate transport device 2 will be explained with reference to Figures 6 to 15. The main operation flow shown in Figure 6 is mainly controlled by the transport control unit 8, with some involvement from parts of the component mounting machine 1 other than the substrate transport device 2 and the operator. In step S1 of Figure 6, a setup change operation is performed to change the type of substrate K from the current substrate type to the next substrate type. The operator slides one of the support plates 29 and guide rails 21 to match the width dimension of the substrate K of the next substrate type, and adjusts the light emitter 6 and light receiver 7 to fit the substrate K of the next substrate type. At this point, the exact values ​​of the first separation distance D1 and the second separation distance D2 become unknown. Meanwhile, the tape feeder 31, rotary tool 44, and suction nozzle 45 are replaced as needed, and the control device acquires the mounting operation data for the next substrate type.

[0050] In the next step S2, the first substrate K is loaded into the loading end of the transport path. In the next step S3, the first calculation unit 81 operates. Details of step S3 are shown in the suboperation flow in Figure 7, the schematic diagram in Figure 8, and the schematic diagram of a modified example in Figure 9. As shown in step S12 of Figures 8 and 9, the substrate K is loaded into the machine by the substrate loading device or external transport device, with its front end KF placed on the conveyor belt 22 and its rear end KR positioned outside the machine beyond the first position P1 near the loading end. At this point, the transport control unit 8 does not know the exact position of the substrate K.

[0051] In step S11 of Figure 7, the first calculation unit 81 sets a low-speed movement speed VL and uses it until step S16 is completed. In the next step S12, the first calculation unit 81 transports the substrate K in the forward direction AJ, passes the first position P1, and stops it. In this operation, it is sufficient that the rear end KR of the substrate K passes the first position P1 and moves to the downstream side; precise position control is not required. In the next step S13, the first calculation unit 81 transports the substrate K in the reverse direction AG. In the next step S14, the first calculation unit 81 uses the first sensor 51 to detect the rear end KR of the substrate K at the first position P1.

[0052] In the next step S15, the first calculation unit 81 again causes the substrate K to be transported in the forward direction AJ. In the next step S16, the first calculation unit 81 causes the second sensor 52 to detect the front end KF of the substrate K at the second position P2. In the next step S17, the first calculation unit 81 determines the travel distance M1 of the conveyor belt 22 between the two detections in steps S14 and S16. Specifically, the travel distance M1 is obtained by multiplying the number of positive pulses of the pulse motor 23 required from step S14 to step S16 by the unit distance. The travel distance M1 of the conveyor belt 22 can be considered equal to the transport distance of the substrate K because the possibility of slippage of the substrate K is low. As shown in step S17 of Figure 8, the first calculation unit 81 calculates the first separation distance D1 by adding the length dimension LK to the transport distance of the substrate K.

[0053] In the modified example shown in step S16 of Figure 9, the first calculation unit 81 causes the second sensor 52 to detect the rear end KR of the substrate K at the second position P2. In step S17 of this embodiment, the first calculation unit 81 can use the travel distance M2 of the conveyor belt 22 between the two detections in steps S14 and S16 as the transport distance of the substrate K and use it as the first separation distance D1. After the first separation distance D1 is calculated, the execution of the operation flow returns to step S4 in Figure 6.

[0054] In step S4, the second calculation unit 82 operates. Details of step S4 are shown in the sub-operation flow in Figure 10 and the schematic diagram in Figure 11. At the time the second calculation unit 82 operates, the position of the substrate K at the end of step S16 is maintained, as shown in Figure 11. That is, the front end KF of the substrate K is stopped at the second position P2.

[0055] In step S21 of Figure 10, the second calculation unit 82 moves the substrate camera 46 to align its optical axis 461 with a predetermined stop position ST. In the next step S22, the second calculation unit 82 causes the substrate camera 46 to image the substrate K and acquire image data. In the next step S23, the second calculation unit 82 causes the image processing unit 91 to perform image processing on the image data to detect the position of the front end KF of the substrate K, i.e., the second position P2. In the next step S24, the second calculation unit 82 calculates the second separation distance D2 between the stop position ST and the second position P2.

[0056] Note that the position where the substrate camera 46 takes an image does not need to coincide with the stop position ST; it is sufficient if it is a position where the front edge KF of the substrate K can be detected by image processing. Nevertheless, by having the substrate camera 46 take an image at the stop position ST, which is the target detection position of the second sensor 52, the front edge KF will be positioned approximately in the center of the imaging field, thereby improving the position detection accuracy of the second position P2. If the substrate camera 46 were to take an image at a position other than the stop position ST, the front edge KF of the substrate K may not be within the imaging field, or the image processing error may increase due to imaging the front edge KF from diagonally above (for example, if the substrate K is warped). After the second separation distance D2 is calculated, the execution of the operation flow returns to step S5 in Figure 6.

[0057] In step S5, the transport control unit 8 moves the conveyor belt 22 at a low speed VL by a distance equal to half the length dimension LK plus the second separation distance D2, and stops the first substrate K at the stop position ST. Next, the component transfer device 4 performs the component mounting operation on the first substrate K. After that, the transport control unit 8 transports the first substrate K to the discharge end and discharges it out of the machine.

[0058] In the next step S6, the stop position adjustment unit 83 performs initial setup of the time chart used for transport control of the second and subsequent substrates K. This time chart is shown in Figure 12 and is set based on the calculated first separation distance D1 and second separation distance D2, with the assumption that no slippage of the substrate K occurs while using the normal travel speed VH. The horizontal axis in Figure 12 shows the passage of time T. The upper graph shows the output signal of the first sensor 51, the middle graph shows the output signal of the second sensor 52, and the lower graph shows the travel speed of the conveyor belt 22. Since there is an assumption that no slippage of the substrate K occurs, the travel speed and travel distance of the conveyor belt 22 match the transport speed and transport distance of the substrate K. The positions of the substrate K corresponding to times T0, T1, T2, and T6 in Figure 12 are shown in Figure 13.

[0059] As shown in Figure 12, at time T0, when the second and subsequent substrates K are brought to the input end, the first sensor 51 outputs an ON signal and the second sensor 52 outputs an OFF signal. The conveyor belt 22 begins moving at an unspecified time, but normally transports the substrates K in the forward direction AJ at a moving speed VH. At time T1, the ON signal of the first sensor 51 switches to an OFF signal, and the rear end KR of the substrate K is detected. At time T2, the OFF signal of the second sensor 52 switches to an ON signal, and the front end KF of the substrate K is detected. The area of ​​the rectangular region A, shown by the upward-sloping hatching, between time T1 and time T2, corresponds to the theoretical travel distance Mth, which is obtained by subtracting the length dimension LK from the first separation distance D1. Time T2 is set relative to time T1 so that this relationship holds. In other words, time T2 is set to be delayed relative to time T1 by the amount of time obtained by dividing the theoretical travel distance Mth by the normal travel speed VH.

[0060] The conveyor belt 22's speed (the transport speed of the substrate K) is maintained at its normal speed VH until time T4, which is later than time T2. After time T4, it is decelerated at a constant rate, becoming zero at time T6. At time T6, the substrate K stops at a predetermined stopping position ST. The area of ​​the trapezoidal region B, indicated by the downward-sloping hatching between time T2 and time T6, corresponds to the transport distance the substrate K is transported from the time the second sensor 52 detects the front end KF of the substrate K, i.e., the distance MR the conveyor belt 22 moves. This distance MR is the sum of half the length dimension LK of the substrate K and the second separation distance D2. A constant deceleration is set so that this relationship holds, and times T4 and T6 are set to be delayed relative to time T2. Note that even if the deceleration is not constant and is represented by a predetermined curve, times T4 and T6 can still be set.

[0061] In the next step S7, the second substrate K is loaded into the loading end of the transport path. In the next step S8, the stop position adjustment unit 83 operates to adjust (correct) the initially set time chart to adjust the stop position. Details of step S8 are shown in the sub-operation flow in Figure 14, the adjustment time chart in Figure 15, and the schematic diagram in Figure 16. The horizontal axis of the adjustment time chart shows the same elapsed time T as the initially set time chart in Figure 12. In addition, the region B of the time chart is divided into a rectangular region B1 indicated by horizontal hatching lines and a trapezoidal region B2 indicated by downward sloping hatching lines in the adjustment time chart. Furthermore, a parallelogram region C indicated by vertical hatching lines is added to the adjustment time chart.

[0062] In step S31 of Figure 14, the stop position adjustment unit 83 sets the normal movement speed VH and uses it for transporting the substrate K. In the next step S32, the stop position adjustment unit 83 resets the clock 85 and starts. In the next step S33, the stop position adjustment unit 83 transports the substrate K in the forward direction AJ using the conveyor belt 22. In the next step S34, the stop position adjustment unit 83 uses the first sensor 51 to detect the rear end KR of the substrate K at the first position P1. The operations up to this point correspond to the time T0 to time T1 of the adjustment time chart and are no different from the initially set time chart. Also, the position of the substrate K at time T0 and time T1 in the schematic diagram of Figure 16 is no different from the schematic diagram of Figure 13.

[0063] In the next step S35, the stop position adjustment unit 83 continues the forward transport AJ of the substrate K, and the second sensor 52 detects the front end KF of the substrate K at the second position P2. If slippage occurs in the transport direction of the substrate K, the time T3 at which the second sensor 52 detects the front end KF of the substrate K will be shifted from the initial time T2. The following explanation will use the case where slippage occurs upstream (opposite to the direction of travel) of the substrate K between time T1 and time T3 as an example. Note that if slippage occurs downstream of the substrate K between time T1 and time T3, the following explanation can be appropriately modified and applied.

[0064] In the next step S36, the stop position adjustment unit 83 obtains the difference time ΔT1 measured by the clock 85. The difference time ΔT1 represents the time by which time T3 is delayed from time T2 due to the upstream slip of the substrate K. Here, the actual travel distance Mrl of the conveyor belt 22 required from time T1 to time T3 is greater than the theoretical travel distance Mth by the difference distance ΔM, as shown in Figure 16. The difference distance ΔM is shown in Figure 15 as the area of ​​region B1 of the conveying speed of the conveyor belt 22 corresponding to the difference time Δ1 (between time T2 and time T3). Therefore, in step S37, the stop position adjustment unit 83 calculates the difference distance ΔM by multiplying the difference time ΔT1 by the normal travel speed VH. This method using the clock 85 simplifies the calculation process compared to the method of counting the drive pulses of the pulse motor 23.

[0065] In the next step S38, the stop position adjustment unit 83 adjusts the travel distance (MR1~MR3) to move the conveyor belt 22 after time T3 based on the difference distance ΔM. The adjustment method involves delaying the initially set deceleration start time T4 and stop time T6 to time T5 and time T7, respectively, to add a travel distance corresponding to region C. The specific method for adjusting the travel distance (MR1~MR3) varies depending on the detailed structure and operating characteristics of the substrate transport device 2, as well as its compatibility with the substrate K. For this reason, the stop position adjustment unit 83 selectively uses the following methods 1) to 3). It is preferable to conduct experiments or simulations to improve the accuracy of the adjusted travel distance (MR1~MR3).

[0066] Method 1) If the slip rate obtained by dividing the difference distance △M by the actual travel distance Mrl is expected to occur at a similar rate from time T3 onward, set a travel distance MR1 that is larger than the initial travel distance MR. In other words, set the time difference ΔT2 between time T4 and time T5, and the time difference ΔT2 between time T6 and time T7, to be larger than the difference time △T1, thereby making the area of ​​region C larger than the area of ​​region B1.

[0067] Method 2) If it is assumed that no slippage of the substrate K occurs after time T3, set the travel distance MR2 to be equal to the initial travel distance MR. In other words, set the difference time ΔT2 to be equal to the difference time ΔT1, and make the area of ​​region C equal to the area of ​​region B1. This method is applied, for example, when the absolute value of the deceleration when using the normal travel speed VH is smaller than the acceleration, and the substrate K slips upstream but not downstream.

[0068] Method 3) When it is assumed that the substrate K will slip downstream after time T3, set a travel distance MR3 that is smaller than the initial travel distance MR. In other words, set the difference time ΔT2 to be smaller than the difference time ΔT1, making the area of ​​region C smaller than the area of ​​region B1. This method is applied, for example, when the substrate K slips upstream due to the initial acceleration when using the normal travel speed VH, and then slips downstream due to the subsequent deceleration.

[0069] In the next step S39, the stop position adjustment unit 83 moves the conveyor belt 22 by the travel distance (MR1 to MR3) set in step S38 to transport and stop the substrate K. After stopping, the substrate K is positioned by the clamping operation of the clamping device 24. In the next step S40, the substrate camera 46 and image processing unit 91 operate to detect the actual stopping position of the substrate K. The stop position adjustment unit 83 determines whether the actual stopping position is within the tolerance range from the predetermined stopping position ST. If it is not within the tolerance range, in step S41, the stop position adjustment unit 83 re-transports the substrate K to correct the actual stopping position. In this case, the stop position adjustment unit 83 controls the transport of the substrate K in the reverse direction as needed. After the completion of step S41, and if it is within the tolerance range in step S40, the execution of the operation flow returns to step S9 in Figure 6.

[0070] In step S9, the component transfer device 4 performs the component mounting operation on the second substrate K. Next, the transport control unit 8 transports the second substrate K to the discharge end and discharges it outside the machine. In the next step S10, the transport control unit 8 determines whether the mounting operation on the last substrate K among multiple substrates K of the same type has been completed. If it is not the last, the execution of the operation flow returns to step S7, and the operation on the third and subsequent substrates K is repeated. Note that the transport and discharge of the second substrate K from the stopping position ST in step S9 and the loading and loading of the third substrate K to the stopping position ST in the next step S7 may occur simultaneously. If it is the last substrate K in step S10, the operation flow ends.

[0071] In the prior art, the first separation distance D1 and the second separation distance D2 were fixed values. However, in this embodiment, each time the type of substrate K is changed, the substrate K is transported and the first separation distance D1 and the second separation distance D2 are calculated (measured). Therefore, in this embodiment, transport control can be performed based on accurate first and second separation distances D1 and D2, and the frequency of executing step S41 can be reduced compared to the prior art. This reduces the number of times the substrate K is re-transported, and in addition, by setting the maximum transport speed as the normal transport speed VH, the transport efficiency of the substrate K can be increased. Ultimately, the production efficiency of the component mounting machine 1 can be increased.

[0072] According to the substrate transport device 2 of this embodiment, the first calculation unit 81 transports the substrate K and causes the first sensor 51 and the second sensor 52 to detect the front end KF or rear end KR of the substrate K, thereby calculating the first separation distance D1 between the first position P1 and the second position P2 based on the transport distance of the substrate K. Therefore, the first separation distance D1, which corresponds to the relative positional relationship between the two detection positions, can be accurately determined.

[0073] 5. Application Examples In this embodiment, even when the conveyor belt 22 moves at a low speed VL, there is a concern that the substrate K may slip due to unforeseen factors. For this reason, in this application example, a measuring jig ZK, as illustrated in Figure 17, is used instead of the substrate K. The measuring jig ZK has the same length LK, width, and thickness dimensions as the substrate K. Furthermore, the measuring jig ZK has a slip prevention portion ZS on the back surface that contacts the conveyor belt 22 to reduce slippage. The slip prevention portion ZS is formed using, for example, a friction material with a high coefficient of friction with respect to the conveyor belt 22, an adhesive material that adheres to the conveyor belt 22, or a locking material that locks the conveyor belt 22.

[0074] In the application example, the first calculation unit 81 can accurately calculate the first separation distance D1 because the measuring jig ZK is less likely to slip than the substrate K, even when using the normal moving speed VH. The second calculation unit 82 can calculate the second separation distance D2 with the same accuracy as in the embodiment using the substrate K. The stop position adjustment unit 83 can perform transport control and stop position adjustment from the first substrate K among a plurality of substrates K of the same type. The effects that occur in the application example are the same as in the embodiment, so a description is omitted.

[0075] 6. Applications and Variations of Embodiments Although the detection light LDs of the first sensor 51, second sensor 52, and third sensor 53 are projected in the width direction (horizontal direction) of the substrate K, the detection light LDs may also be projected in the thickness direction (vertical direction) of the substrate K. Furthermore, the first sensor 51, second sensor 52, and third sensor 53 may be reflection detection type sensors that detect when the detection light LDs are reflected by the substrate K. In addition, the third sensor 53 on the discharge end side of the transport path may be omitted. Moreover, the moving member that holds and moves the substrate K is not limited to the conveyor belt 22, but may be a shuttle member that moves back and forth along the transport path. The predetermined stopping position ST may be the position where the front end KF or rear end KR of the substrate K stops.

[0076] Furthermore, in the sub-operation flow shown in Figure 14, the stop position adjustment unit 83 individually determines the difference time △T1 and difference distance △M for all substrates K from the second onward. Alternatively, the stop position adjustment unit 83 may apply the difference time △T1 and difference distance △M determined for the second substrate K to the third and subsequent substrates K. In other words, in this embodiment, a difference time △T2 that differs for each individual substrate K is used, but in this alternative method, the operation of the stop position adjustment unit 83 can be simplified by using a constant difference time ΔT2. In addition, the substrate transport device 2 of this embodiment can be applied to other types of substrate handling machines other than the component mounting machine 1. Various other applications and modifications are possible for this embodiment and application example. [Explanation of Symbols]

[0077] 1: Component mounting machine 2: PCB transport device 21: Guide rail 22: Conveyor belt 23: Pulse motor 24: Clamping device 3: Component supply device 4: Component transfer device 46: PCB camera 51: First sensor 52: Second sensor 53: Third sensor 6: Light emitter 7: Light receiver 8: Transport control unit 81: First calculation unit 82: Second calculation unit 83: Stop position adjustment unit 84: Pulse counter 85: Clock 9: Transfer control unit 91: Image processing unit K: PCB KF: Front end KR: Rear end KM: Center LK: Length dimension P1: First position P2: Second position ST: Stop position D1: First separation distance D2: Second separation distance M1, M2, MR, MR1, MR2, MR3: Travel distance △M: Difference distance △T1: Difference time VL: Low-speed travel speed VH: Normal travel speed ZK: Measurement jig ZS: Anti-slip part

Claims

1. A first sensor that detects whether or not the substrate is present at the first position in the substrate transport path, A second sensor that detects whether or not the substrate is present at a second position downstream of the first position in the transport path, A first calculation unit transports the substrate along the transport path, causing one of the first and second sensors to detect the front or rear end of the substrate, then transports the substrate again, causing the other of the first and second sensors to detect the front or rear end of the substrate, and calculates a first separation distance between the first and second positions based on the transport distance the substrate travels between the two detections. A substrate transport device equipped with the following features.

2. The substrate transport device is A moving member that moves along the transport path while holding the substrate and allowing it to slide in the transport direction, The system includes a transport drive unit for moving the aforementioned moving member, The first calculation unit controls the transport drive unit to move the moving member and transport the substrate, and determines the transport distance of the substrate based on the distance traveled by the moving member. The substrate transport apparatus according to claim 1.

3. The substrate transport device according to claim 2, wherein the first calculation unit moves the moving member at a slow moving speed that makes it difficult for the substrate to slip, and the moving distance of the moving member is defined as the transport distance of the substrate.

4. The substrate transport device according to claim 2, wherein the first calculation unit uses a measuring jig having the same dimensions as the substrate and having a slip-preventing portion for reducing slippage instead of the substrate, and the travel distance of the moving member is defined as the transport distance of the measuring jig.

5. The moving member is a conveyor belt that moves along the transport path while rotating, The transport drive unit is a pulse motor that rotates the conveyor belt by control using drive pulses, The first calculation unit determines the travel distance of the conveyor belt based on the number of pulses of the drive pulse. A substrate transport apparatus according to any one of claims 2 to 4.

6. The first calculation unit transports the substrate in the forward direction, passes it through the first position, then transports the substrate in the reverse direction, causes the first sensor to detect the rear end of the substrate, and then transports the substrate in the forward direction, causing the second sensor to detect the front or rear end of the substrate. A substrate transport apparatus according to any one of claims 1 to 4.

7. The substrate transport device according to claim 6, wherein the first calculation unit causes the first sensor to detect the rear end of the substrate and the second sensor to detect the front end of the substrate, and calculates the first separation distance by adding the length dimension of the substrate in the transport direction to the transport distance of the substrate between the two detections.

8. The substrate transport device according to claim 6, wherein the first calculation unit causes the first sensor to detect the rear end of the substrate and the second sensor to detect the rear end of the substrate, and the transport distance of the substrate between the two detections is defined as the first separation distance.

9. The system includes a detection unit that controls a detection unit capable of detecting the substrate located in the transport path, causing the second sensor to detect the position of the substrate when it detects the front or rear end of the substrate, and a second calculation unit that calculates a second separation distance between a predetermined stopping position for stopping the substrate and the second position based on the detection result. The substrate transport apparatus according to claim 1.

10. A moving member that moves along the transport path while holding the substrate, A transport drive unit that moves the aforementioned moving member, A transport control unit controls the transport drive unit based on the first separation distance and the second separation distance to move the moving member and stop the substrate at the stop position, A substrate transport apparatus according to claim 9, comprising:

11. The moving member allows the substrate it holds to slide in the transport direction, When the transport control unit transports the substrate in the forward direction and stops it at the stop position, it adjusts the distance the transport member moves after the second sensor detects the front end of the substrate, based on the difference between the actual distance the moving member travels from the time the first sensor detects the rear end of the substrate until the second sensor detects the front end of the substrate, and the theoretical distance traveled by subtracting the length dimension of the substrate in the transport direction from the first separation distance. The substrate transport apparatus according to claim 10.

12. The transport control unit calculates the difference distance by multiplying the moving speed of the moving member by the difference time between the time when the second sensor detects the front end of the substrate and the time when the moving member has moved by the theoretical distance. The substrate transport apparatus according to claim 11.

13. The substrate transport apparatus according to any one of claims 9 to 12, wherein the detection unit is an imaging image processing device that detects the position of the substrate by performing predetermined image processing on an image obtained by imaging the substrate.

14. A substrate transport apparatus according to any one of claims 10 to 12, wherein the first calculation unit and the second calculation unit operate with respect to the first of a plurality of substrates of the same type, and the transport control unit operates with respect to the second and subsequent substrates.

15. The first position is set at the loading end of the transport path, allowing for positional errors. The second position is set to a predetermined stopping position on the transport path that stops the substrate in the transport direction, allowing for a positional error. A substrate transport apparatus according to any one of claims 1 to 4 or 9 to 12.

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