JP2006041260A - Method for correcting nozzle position of electronic component mounting apparatus - Google Patents

Abstract

To position a nozzle with higher accuracy.
SOLUTION: A base 104, a head 110 provided with a suction nozzle 111, an X-axis guide 121 for guiding the head along the X-axis direction, and a Y-axis guide 122 for guiding the X-axis guide along the Y-axis direction. In the nozzle position correction method of the electronic component mounting apparatus 100, including the mark display unit 130 on which a plurality of recognition marks M1 to Mn are displayed, and the first and second cameras 112 and 113 provided on the head. An imaging process for imaging each recognition mark with two cameras, a displacement amount obtaining process for obtaining an imaging position deviation amount for each camera, and a Y-axis direction imaging position deviation amount for two recognition marks respectively captured by the two cameras A Y-axis misalignment specifying step for calculating the amount of misalignment in the Y-axis direction of the nozzle from the relative positional relationship between each camera and the nozzle; And a positioning step.
[Selection] Figure 12

Description

  The present invention relates to a nozzle positioning correction method for an electronic component mounting apparatus that moves a head for mounting an electronic component along a guide.

Conventional electronic component mounting for mounting an electronic component on a substrate by a head mounted with a nozzle for sucking the electronic component and an XY movement mechanism that enables the head to be positioned at an arbitrary position on the XY plane In the apparatus, an error may occur in the mounting position with respect to the target position coordinates due to various causes (for example, processing accuracy of parts, assembly accuracy, thermal expansion, etc.).
In order to correct such an error, a measurement board in which reference marks with known position coordinates are scattered on the surface is installed at the substrate holding position, and each reference is obtained by imaging with a camera mounted on the head. The imaging position error of the mark is acquired. Further, when mounting electronic components, a prior art that corrects an imaging position error by regarding that an imaging position error of a reference mark close to the mounting target position coordinate is approximated to an error in nozzle positioning is disclosed. (For example, refer to Patent Document 1).
JP-A-8-16787

However, in the above conventional example, when the camera and the nozzle mounted on the head are separated from each other in the XY plane, the posture and orientation change due to the movement of the head (for example, the deflection of the guide that supports the head). Etc.) has an inconvenience that an error caused by this cannot be corrected.
An object of the present invention is to correct an error caused by a change in posture and orientation of the head due to movement.

  According to the first aspect of the present invention, there is provided a base having a substrate holding part for mounting an electronic component on a substrate, a head having a nozzle for adsorbing an electronic component mounted on the substrate, and a substrate held by the substrate holding part. An X-axis guide that guides the head along the X-axis direction parallel to the electronic component placement surface, and an X-axis guide that guides the X-axis guide along the Y-axis direction parallel to the electronic component placement surface. Two Y-axis guides provided and a plurality of Y-axis guides provided on the base side, arranged in a line, and each position coordinate in the XY coordinate system having the arrangement direction as the X-axis direction is known In a nozzle position correction method for an electronic component mounting apparatus, comprising: a mark display portion on which a recognition mark is displayed; and first and second cameras that are arranged on the head along the X-axis direction and image the base side. For each of the first and second cameras Then, the imaging center position is positioned at a known position coordinate in the XY coordinate system, and each recognition mark is imaged in each of the imaging process for imaging each recognition mark and each of the first and second cameras. A shift amount acquisition step for obtaining a shift amount of the imaging position from the center of the image based on the captured image, and two recognition marks close to the X coordinate of the first and second cameras when the nozzle is positioned at the target position coordinate Based on the Y-axis shift amount specifying step of calculating the Y-axis shift amount of the nozzle from the imaging position shift amount in the Y-axis direction and the relative positional relationship between each camera and the nozzle, and the Y-axis shift amount And a positioning step of positioning the nozzle at the target position coordinates while performing correction.

In the above configuration, for example, when the X-axis guide is bent in the Y-axis direction, if the head moves along the X-axis guide, an error in the Y-axis direction is caused according to each position on the X-axis guide. Will occur.
Accordingly, when a plurality of recognition marks arranged along the X-axis direction are sequentially imaged according to the respective known position coordinates, the Y-axis direction component of the imaging position shift amount of each recognition mark is moved in the Y-axis direction of the X-axis guide. It is calculated as the amount of bending.
As a result, when the nozzle is positioned at the target position coordinates, the amount of imaging position deviation in the Y-axis direction for the two recognition marks close to the X coordinates of the first and second cameras is obtained. The amount of deviation in the Y-axis direction at the point (two camera positions) can be approximately obtained.
In addition, if the relative positional relationship between each camera on the head and the nozzle is known, the nozzle is generated depending on the arrangement ratio of the “nozzle and the first camera” and the “nozzle and the second camera” in the X-axis direction. The amount of deviation in the Y-axis direction can be calculated.

  In addition, it is desirable to select the closest recognition mark for "two recognition marks close to the X coordinate of the first and second cameras", but there are recognition marks on both sides across the camera position. In addition, a recognition mark that is always located on the left (or right) may be selected. This makes it unnecessary to determine which of the two recognition marks located on both sides is closer. Even in this case, the first or second closest recognition mark is selected.

  The invention described in claim 2 has the same configuration as that of the invention described in claim 1, and is close to the X coordinate of one of the first and second cameras when the nozzle is positioned at the target position coordinate. A first X-axis misalignment specifying step for identifying the imaging position misalignment amount of the recognition mark in the X-axis direction as the misalignment amount of the nozzle in the X-axis direction is provided. In the positioning step, correction based on the misalignment amount in the X-axis direction The nozzle is positioned at the target position coordinates while performing the above.

In the above configuration, for example, when the X-axis guide is bent in the direction perpendicular to the XY plane (hereinafter referred to as the Z-axis direction), when the head moves along the X-axis guide, At both ends of the direction, a difference in height occurs in the Z-axis direction, and an inclination centering on the Y-axis direction occurs. As a result, the tip of the nozzle facing the base side will cause an error in the X-axis direction. Similarly, since each camera is also directed to the base side, an error in the X axis direction occurs at the imaging center.
Therefore, when a plurality of recognition marks arranged along the X-axis direction are sequentially imaged according to the respective known position coordinates, the X-axis direction component of the imaging position shift amount of each recognition mark is moved in the Z-axis direction of the X-axis guide. It is calculated | required as an error amount of the X-axis direction resulting from bending | flexion.
Thereby, by obtaining the imaging position shift amount in the X-axis direction for two recognition marks close to the X coordinate of the first or second camera when the nozzle is positioned at the target position coordinate, The amount of deviation in the X-axis direction can be obtained approximately. Note that the tilt angle around the Y-axis direction generated in the head due to the deflection of the X-axis guide in the Z-axis direction is not so large that the X-axis guide is visibly bent. Since the amount of misalignment in the X-axis direction that occurs in each of the first camera, the second camera, and the nozzle is almost uniform as long as it is on the head, the error in one of the cameras can be approximated to the nozzle. It can be regarded as an error that occurs.

  It should be noted that the “recognition mark close to the X coordinate of either camera” is preferably the closest recognition mark, but if there are recognition marks on both sides of the camera position, it is always left You may select the recognition mark located in (or right side). This makes it unnecessary to determine which of the two recognition marks located on both sides is closer. Even in this case, the first or second closest recognition mark is selected.

  The invention described in claim 3 has a configuration similar to that of the invention described in claim 1 or 2, and is a set of two recognition marks separated by a distance approximately equal to the distance between the two cameras in the X-axis direction on the head. A plurality of images are extracted, the difference in the imaging position deviation amount in the X-axis direction that occurs in each camera with the two recognition marks in each group is obtained, the difference in the imaging position deviation amount in the X-axis direction of each group is averaged, and the imaging The inter-camera distance specifying step for correcting the distance between the two cameras in the X-axis direction based on the average value of the positional deviation amount, the two inter-camera distances in the X-axis direction, and each camera and nozzle And a second X-axis shift amount specifying step for calculating the displacement amount of the nozzle in the X-axis direction based on the relative positional relationship. In the positioning step, correction based on the shift amount in the X-axis direction is performed. While the nozzle at the target position coordinates It adopts a configuration that, for positioning.

In the above configuration, for example, the influence of the change in the length in the X-axis direction of the head is calculated from the distance between the two cameras based on the influence of the temperature change as an example. In other words, two recognition marks with a distance approximately equal to the distance between the two cameras (a pair of recognition marks equal to the distance between the two cameras is preferable, but if they do not match, the closest recognition mark pair or the second closest recognition mark) ) And the imaging position deviation amount of each recognition mark at each camera is obtained. As a result, the amount of X-axis direction deviation generated around each camera position is obtained, and the amount of expansion / contraction generated in the head at the distance between the two cameras is calculated by subtracting these X-axis direction deviation amounts.
Similarly, select multiple pairs of other recognition marks that are separated by the distance between the two cameras, determine the amount of expansion / contraction that occurred in the head at the distance between the cameras, and average them, thereby affecting the effects of variation. A value with reduced is extracted.
By using the inter-camera distance determined in this way for calculating the X-axis shift amount generated in the nozzle in the positioning step, the X-axis shift amount can be calculated more precisely.

  The invention described in claim 4 has the same configuration as that of the invention described in claim 1, 2, or 3, and in the imaging step, each recognition mark is imaged by each camera at a plurality of temperatures, and the amount of deviation is acquired. In the process, for each camera, the amount of imaging position deviation is obtained for each temperature, and before the positioning process, a temperature detection process for detecting the temperature in the apparatus is provided, and under a temperature closer to the detection temperature in the temperature detection process The image pickup position deviation amount is referred to.

  In the above configuration, by performing imaging at each temperature, an imaging position shift amount generated at each temperature is determined as a Y-axis shift amount specifying step, a first X-axis shift amount specifying step, and a second X-axis shift amount specifying. It can be reflected in the process or the inter-camera distance specifying process, and various misalignment corrections can be performed in consideration of the influence of temperature.

  The invention according to claim 1 occurs at any two camera positions along the X-axis direction by imaging a plurality of recognition marks arranged along the X-axis direction whose position coordinates are known with two cameras. The amount of deviation in the Y-axis direction can be obtained approximately. Further, since the Y-axis direction deviation amount at the nozzle is obtained from the Y-axis direction deviation amount generated at two points of the head, the position error due to head posture and orientation variation can be obtained more accurately, and by correcting this, Electronic components can be mounted with higher accuracy.

  According to the second aspect of the present invention, the plurality of recognition marks arranged along the X-axis direction whose position coordinates are known are imaged by any one of the cameras provided on the same head as the nozzle, so that the X-axis direction is obtained. The amount of deviation in the X-axis direction that occurs at any camera position along can be acquired approximately. Furthermore, when the amount of deviation in the X-axis direction is caused by the deflection of the X-axis guide in the Z-axis direction, the amount of imaging position deviation in the X-axis direction is approximately equal to the amount of deviation in the X-axis direction that occurs at the nozzle tip. Therefore, the position error due to head posture and orientation variation can be obtained more accurately, and by correcting this, electronic components can be mounted with higher accuracy.

  According to the third aspect of the present invention, in the two recognition marks that are separated by the same distance from the two cameras, the amount of expansion / contraction of the head generated between the two cameras is obtained from the amount of imaging position shift generated in each camera, and a plurality of the same. Since a number of expansion / contraction amounts are obtained from the set of recognition marks and averaged, the expansion / contraction amount of the head in the X-axis direction can be determined more precisely. Furthermore, since the precise expansion / contraction amount of the head in the X-axis direction is reflected in the calculation of the deviation amount in the X-axis direction at the nozzle position, the nozzle position can be more accurately positioned in the X-axis direction.

  In the invention of claim 4, by performing imaging at each temperature, the imaging position deviation amount generated at each temperature is determined as the Y-axis deviation amount specifying step, the first X-axis deviation amount specifying step, and the second X-axis. It can be reflected in the deviation amount identification process or the inter-camera distance identification process, and it is possible to perform various deviation amount corrections that take into account the effects of temperature, so that electronic components can be mounted more accurately at each temperature. It becomes possible.

(Overall configuration of the embodiment)
An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a perspective view of an electronic component mounting apparatus 100 according to the present embodiment.
The electronic component mounting apparatus 100 mounts various electronic components on a substrate. As shown in FIG. 1, a base 104 that supports each component described later and a plurality of electronic components to be mounted are provided. An electronic component feeder 101 (only one is shown in FIG. 1 but actually a plurality of electronic component feeders 101 are arranged along the X-axis direction to be described later), a feeder bank 102 that holds a plurality of electronic component feeders 101 side by side, A substrate transport means 103 for transporting a substrate in a certain direction, a mounting work section for performing electronic component mounting work on a substrate provided in the middle of the substrate transport path by the substrate transport means 103, and a plurality of removable suction nozzles A head 110 serving as a component holding unit that holds 111 and holds an electronic component, and a head moving hand that drives and conveys the head 110 to an arbitrary position within a predetermined range And X-Y gantry 120 as, and an operation control unit 10 for controlling the operation of each of the above structures.
In the following description, one direction orthogonal to each other along the horizontal plane is referred to as an X-axis direction, the other direction is referred to as a Y-axis direction, and a vertical vertical direction is referred to as a Z-axis direction.

(Substrate transport means)
The substrate transport unit 103 includes a transport belt (not shown), and transports the substrate along the X-axis direction by the transport belt.
Further, as described above, a mounting operation unit for mounting electronic components on the substrate is provided in the middle of the substrate transport path by the substrate transport means 103. The substrate transport unit 103 transports the substrate to the mounting work unit and stops, and holds the substrate by a holding mechanism (not shown). That is, a stable electronic component mounting operation is performed while the substrate is held by the holding mechanism.
In this embodiment, the technique related to the position correction of the suction nozzle 111 for mounting the electronic component on the substrate will be mainly described. Therefore, in FIG. 1, the jig substrate 130 used for the position correction is mounted. The state hold | maintained by the holding mechanism in the part is illustrated.

(Electronic parts feeder)
The feeder bank 102 includes a plurality of flat portions along a plurality of XY planes, and a plurality of electronic component feeders 101 are arranged and mounted on the flat portions along the X-axis direction.
In addition, the feeder bank 102 includes a contact portion along the XZ plane that contacts the tip portion of each electronic component feeder 101, and the contact portion is provided at the tip portion of the electronic component feeder 101. A plurality of positioning holes into which the engaging protrusions are inserted are provided along the enclosing direction of the electronic component feeder 101 (not shown).
Further, each electronic component feeder 101 is provided with a latch mechanism for clamping with an elastic force. By engaging the outer end portion of the flat portion of the feeder bank 102 with the latch mechanism, the above-described engaging projections are inserted into the positioning holes. The inserted state is maintained, and the electronic component feeder 101 can be fixed to the feeder bank 102 in a desired posture.

  The electronic component feeder 101 holds a tape reel wound with a tape in which an infinite number of electronic components are encapsulated at a uniform interval on the rear end side, and a transfer portion for electronic components to the head 110 is formed in the vicinity of the front end portion. Has been. Then, in the state of being attached to the feeder bank 102, the tape is transported to the electronic component delivery unit, and the electronic component is supplied to the head 110 positioned at the delivery unit. .

(XY gantry)
FIG. 2 is a plan view of the XY gantry 120. As shown in FIG. 2, two Y-axis guide rails 122 as Y-axis guides mounted on and parallel to the upper surface of the base 104 whose upper surface is parallel to the XY plane, and the two An X-axis guide rail 121 as an X-axis guide supported in a state of being spanned on the Y-axis guide rail 122, and the head along the X-axis direction that guides the head 110 in the Y-axis direction together with the X-axis guide rail 121 An X-axis motor 123 that is a drive source that moves 110 and a Y-axis motor 124 that is a drive source that moves the head 110 in the Y-axis direction via an X-axis guide rail 121 are provided. By driving the motors 123 and 124, the head 110 can be transported to almost the entire region between the two Y-axis guide rails 122.
Further, due to the necessity of the electronic component mounting work, both the feeder bank 102 and the mounting work unit 104 described above are disposed within the transportable area of the head 110 by the XY gantry 120.

Each of the Y-axis guide rails 122 is arranged along the Y-axis direction, and supports both ends of the X-axis guide rail 121 via linear guides. Thereby, the X-axis guide rail 121 can be slid along the Y-axis direction.
The Y-axis motor 124 can move and position the X-axis guide rail 121 along the Y-axis direction via a known transmission mechanism (such as a belt mechanism or a ball screw mechanism).

The X-axis guide rail 121 is disposed along the X-axis direction, and supports the head 110 via a linear guide. Thereby, the head 110 can be slid along the X-axis direction.
The X-axis motor 123 can move and position the X-axis guide rail 121 along the X-axis direction via a known transmission mechanism (such as a belt mechanism or a ball screw mechanism).
The motors 123 and 124 each have their rotation amount detected by a detection means (not shown) and output to the operation control means 10, and are controlled so as to have a desired rotation amount. The suction nozzle 111 and first and second cameras 112 and 113 to be described later are positioned.
Further, each of the motors 123 and 124 may be a linear motor instead of a rotational drive type.

(head)
As shown in FIG. 2, the head 110 has four suction nozzles 111 that hold electronic components by air suction at the tip, and a Z-axis motor that is a drive source that drives these suction nozzles 111 in the Z-axis direction. 114 (see FIG. 4) and a rotation motor 115 (see FIG. 4), which is a rotation drive source for rotating the electronic component held via the suction nozzle 111 around the Z-axis direction.

The respective suction nozzles 111 are supported by the head 110 side by side along the X-axis direction, and each is supported with its longitudinal direction aligned with the Z-axis direction.
Further, each suction nozzle 111 is connected to a negative pressure generation source, and suction and suction of electronic components are performed by performing suction suction at the tip of the suction nozzle 111.
That is, with these structures, at the time of mounting work, the electronic component is sucked from the predetermined electronic component feeder 101 at the tip of the suction nozzle 111, and the suction nozzle 111 is lowered toward the substrate at the predetermined position by the movement of the head 110 and sucked. The mounting operation is performed while adjusting the orientation of the electronic component by rotating the nozzle 111.

  The first and second cameras 112 and 113 are disposed at both ends of the head 110 in the X-axis direction with the suction nozzles 111 interposed therebetween. Each of the cameras 112 and 113 is mounted on the head 110 with its optical axis directed in the Z-axis direction, and performs substrate origin alignment while being positioned at a predetermined position by the XY gantry 120. For this purpose, a positioning mark is imaged. In addition, it is used for various types of imaging for recognizing the state below the head 110 in order to position each suction nozzle 111. Furthermore, it is also used for imaging the jig substrate 130 for correcting the position of the suction nozzle 111 described later.

(Jig substrate)
FIG. 3 is a plan view of the jig substrate 130 as a mark display portion. The jig substrate 130 is mounted on the mounting operation portion of the substrate transfer means 103 only during the preparatory work for position correction of the suction nozzle 111 (details will be described later), and is removed when the electronic component is mounted.
The jig substrate 130 has the recognition marks M1 to Mn displayed at uniform intervals along the straight line at the center thereof. It is desirable that each of the recognition marks M1 to Mn be along a straight line with higher accuracy, but strictly, there is a slight deviation depending on the formation accuracy. Therefore, each of the recognition marks M1 to Mn is measured in advance precisely by a three-dimensional measuring device, and the relative positional relationship is acquired in advance. That is, coordinate data having the origin recognition mark M1 as the origin and the straight line connecting the recognition marks M1 and Mn at both ends as one coordinate axis of the orthogonal coordinate system is obtained by the measurement, and the operation control means 10 performs the processing. It is prepared as data that can be used.
Note that the jig substrate 130 is mounted on the mounting operation portion of the substrate transport unit 103 so that the rows of the recognition marks M1 to Mn are substantially along the X-axis direction when used. In addition, when mounting, the length of each row of the recognition marks M1 to Mn in the X-axis direction is a range in which the electronic component is mounted on the board, and a range in which the electronic component is received from each electronic component feeder 101. The posture detection means 105 is set to a length that can cover the X-axis direction. That is, since the jig substrate 130 is used to correct the positioning position of each suction nozzle 111, it is necessary to cover all the positions where the suction nozzle 111 can be positioned in the X-axis direction.
Note that the jig substrate 130 is made of a material (for example, a glass plate) that hardly changes in expansion due to a temperature change.

(Operation control means)
FIG. 4 is a block diagram showing a control system of the electronic component mounting apparatus 100. As shown in FIG. 4, the operation control means 10 mainly includes an X-axis motor 123 of the XY gantry 120, a Y-axis motor 124, and a Z-axis motor 114 that actually raises and lowers each suction nozzle 111 in the head 110. Is provided individually for each suction nozzle 111, but only one is shown in FIG. 4), but a rotation motor 115 for rotating the suction nozzle 111 (actually provided for each suction nozzle 111 individually). 4, only one is shown), and the operation of the first camera 112 and the second camera 113 provided on the head 110 is controlled and the temperature sensor 106 provided on the XY gantry 120 controls the XY gantry. 120 operating environment temperatures are detected.
The operation control means 10 stores a CPU 11 that executes various processes and controls in accordance with a predetermined control program, a system ROM 12 that stores programs for executing various processes and controls, and various data. A RAM 13 serving as a work area for various processes, an I / F (interface) 14 for connecting the CPU 11 to various devices, an operation panel 15 for inputting data required for various settings and operations, It has a non-volatile storage device 17 made of, for example, an EEPROM or the like in which data for executing various processes and controls is stored, and a display monitor 18 for displaying the contents of various settings and the results of inspections to be described later. Yes. Each of the motors 114, 115, 123, and 124 described above is connected to the I / F 14 via a motor driver (not shown).

The storage device 17 stores mounting position coordinate data indicating the mounting position of each electronic component on the substrate, and position coordinate data indicating the receiving position of the electronic component to be mounted.
Then, the CPU 11 moves the head 110 to a preset position when the substrate is held in the mounting operation unit of the substrate transport unit 103 by a predetermined mounting program, and the reference of the substrate is detected by any of the cameras 112 and 113. Operation control for imaging the value mark is performed. Further, the CPU 11 calculates the origin position of the board from the captured image, acquires the position coordinates of the origin position in the coordinate system of the electronic component mounting apparatus 100, and each position coordinate of the mounting position stored in the storage device 17. Data is converted into the coordinate system of the electronic component mounting apparatus 100. Then, the CPU 11 drives the X-axis motor 123 and the Y-axis motor 124 by a predetermined driving amount to position the suction nozzle 111 on the head 110 at each mounting position, and sequentially executes the mounting operation of the electronic components. .
Further, the CPU 11 controls the operation of the Z-axis motor 114 and adjusts the tip of the suction nozzle 111 to an appropriate height when receiving and mounting the electronic component.

Further, although not shown in FIG. 1, the electronic components held upward and held by the respective suction nozzles 111 are imaged from below at a predetermined position within the movable range of the head 110 on the upper surface of the base 104. Attitude detection means 105 is provided. The posture detection unit 105 images the electronic component held by the suction nozzle 111 from below and outputs the image to the operation control unit 10.
On the other hand, the CPU 11 positions the suction nozzle 111 immediately above the posture detection unit 105 after receiving the electronic component and before mounting it, images the electronic component by the posture detection unit 105, and determines from the captured image. While determining the orientation of the electronic component, the drive control of the rotary motor 115 is executed so that the orientation is appropriate.

(Cause of misalignment of suction nozzle)
Here, the cause of the positioning error of the suction nozzle 111 will be described with reference to FIGS.
First, problems of the XY gantry 120 will be described. FIG. 5 is an explanatory view of the XY gantry 120 viewed from above (Z-axis direction), and FIG. 6 is an explanatory view of the XY gantry 120 viewed from the front (Y-axis direction).
Since the X-axis guide rail 121 is moved in the Y-axis direction, an aluminum alloy is used to reduce the material weight. On the other hand, since the base 104 and the Y-axis guide rail 122 are made of iron or an alloy thereof, the X-axis guide rail 121 is caused by the difference in the expansion coefficient of each part due to an increase in the ambient temperature around the electronic component mounting apparatus 100. In some cases, bending in the Y-axis direction may occur as shown in FIG.
When the head 110 moves along the X-axis guide rail 121 having such a bend, the nozzle position is displaced in the Y-axis direction at each position in the X-axis direction as indicated by ΔY shown in FIG. It will be.
For the same reason as described above and the weight of the head 110, the X-axis guide rail 121 may bend in the Z-axis direction as shown in FIG. When the head 110 moves along the X-axis guide rail 121 having such a bend, the nozzle position is deviated from the vertical direction at each position in the X-axis direction as θ1 and θ2 shown in FIG. As a result, the tip position of the suction nozzle 111 is displaced in the X-axis direction.
Further, since the degree of bending of the X-axis guide rail 121 varies depending on the use environment temperature of the electronic component mounting apparatus 100, it is difficult to complete the correction at the stage before the mounting is started by obtaining the deviation amount in advance. .
Further, the head 110 may expand in the X-axis direction due to a temperature change, resulting in a positional shift.
In order to suppress such various displacements, various methods described below are performed.

(Creation of correction tables used for various corrections)
Based on FIGS. 7 to 9, a process of creating a correction table T used for various corrections will be described. FIG. 7 is an explanatory diagram showing a coordinate system developed for each of the recognition marks M1 to Mn of the jig substrate 130, and FIG. 8 shows a deviation amount of the recognition marks M1 to Mn imaged from the camera center position at the time of imaging. FIG. 9 is an explanatory diagram showing a correction table T used for various corrections. Such processing is performed prior to the electronic component mounting operation.

[1] First, when the jig substrate 130 is mounted on the mounting work section of the substrate transport means 103, the CPU 11 positions the first camera 112 of the head 110 at an approximate position by a predetermined correction processing program. Operation control for imaging the recognition marks M1 and Mn located at both ends is performed.
[2] Then, the CPU 11 recognizes the accurate positions of the recognition marks M1 and Mn from the camera center position, and sets a straight line connecting the recognition marks M1 and Mn to the X-axis with the recognition mark M1 as the origin. XY coordinate system is formed.
[3] Further, the CPU 11 converts the coordinate data indicating the relative positional relationship between the recognition marks M1 to Mn stored in advance in the storage device 17 into the XY coordinate system, and (X1, Y1) in the correction table T. , (X2, Y2), (X3, Y3),... (Xn, Yn) are stored in the RAM 13. Since the recognition mark M1 is the origin and the recognition marks M1 and Mn are located on the X axis, X1 = 0, Y1 = 0, and Yn = 0.

[4] Next, the CPU 11 determines the first camera based on the position coordinate data (X1, Y1), (X2, Y2), (X3, Y3),... (Xn, Yn) of the respective recognition marks M1 to Mn. An operation control is performed in which 112 is positioned on each of the recognition marks M1 to Mn and imaging is performed.
[5] Further, the CPU 11 calculates the shift amount of each of the recognition marks M1 to Mn from the camera center position C from the captured image of each of the recognition marks M1 to Mn by using the X component and the Y component (see FIG. 8), and corrects them. (XL1, YL1), (XL2, YL2), (XL3, YL3),... (XLn, YLn) in the table T are stored in the RAM 13.
That is, in an ideal state where the X-axis guide rail 121 is not bent, (XL1, YL1), (XL2, YL2), (XL3, YL3),... (XLn, YLn) are all (0 , 0), however, the amount of positional deviation that occurs in the first camera 112 in the head 110 due to the deflection of the X-axis guide rail 121, the expansion of the head 110, etc. is (XL1, YL1),... (XLn, YLn). Will appear.

[6] Next, the CPU 11 determines the second camera based on the position coordinate data (X1, Y1), (X2, Y2), (X3, Y3),... (Xn, Yn) of the recognition marks M1 to Mn. The operation control is performed in which 113 is positioned on each of the recognition marks M1 to Mn and imaging is performed.
[7] Further, similarly to the case of the first camera 112, the CPU 11 also calculates the amount of XY deviation of each of the recognition marks M <b> 1 to Mn in the case of the second camera 113, and the correction table T (XR1, YR1), (XR2, YR2), (XR3, YR3),... (XRn, YRn) are stored in the RAM 13.
As a result, the positional deviation amount generated in the second camera 113 in the head 110 appears in (XR1, YR1),... (XRn, YRn).
[8] Further, the CPU 11 performs the processes [1] to [7] for each predetermined temperature (for example, every 1 degree Celsius), and acquires the correction table T for each temperature. In order to obtain the correction table T for each temperature, a temperature adjusting means may be provided in the apparatus. However, in this embodiment, the CPU 11 starts the warm-up operation of the XY gantry 120 from the start of the main power supply. The operation control to be performed is performed, the temperature detected by the temperature sensor 106 is watched, and each time the temperature rises once, the processes [1] to [7] are executed.

(Correction processing for head expansion / contraction)
Using the correction table T acquired for each temperature, the camera center distance D0 between the first camera 112 and the second camera 113 caused by expansion and contraction in the head 110 due to temperature change, the camera of the first camera 112 Distance D1 from the center to the nozzle center of the first suction nozzle 111a, distance D2 from the camera center of the first camera 112 to the nozzle center of the second suction nozzle 111b, from the camera center of the first camera 112 Changes ΔD0 to ΔD4 that occur in the distance D3 to the nozzle center of the third suction nozzle 111c and the distance D4 from the camera center of the first camera 112 to the nozzle center of the fourth suction nozzle 111d are calculated. The process will be described with reference to FIG. FIG. 10 is an explanatory diagram showing the arrangement of the cameras 112 and 113 and the suction nozzles 111a to 111d in the head 110 and the relationship between the distances D0 to D4.

[1] First, it is assumed that the initial values of the distances D0 to D4 are precisely measured and stored in the storage device 17 in advance. The distances D0 to D4 are preferably measured by the same method under the same environment as the measurement of the recognition marks M1 to Mn on the jig substrate 130.
When determining the amount of change in each of the distances D0 to D4 at a certain temperature, the CPU 11 uses the predetermined correction processing program to calculate two recognition marks having a distance equal to the distance D0 (or closest to the distance D0). A process of selecting a set {M1, M (α + 1)}, {M2, M (α + 2)} {M3, M (α + 3)}... (Where α = D0 / interval of each recognition mark) is performed.
Note that the number of recognition mark pairs to be selected is arbitrary and follows a preset number. A minimum of one pair is also acceptable.
[2] Then, the CPU 11 determines from the target temperature correction table T that the X component shift amount XR (α + 1) of the second camera 113 at one recognition mark M (α + 1) in the set and the other recognition mark in the set. The deviation XL1 of the X component of the first camera 112 at M1 is read out, and the difference between them is calculated. That is, a calculation is performed in which the left component is subtracted from the right component in the chart of FIG.
It should be noted that the above calculation is performed for all selected recognition mark pairs. The difference value calculated for each group corresponds to the change amount ΔD0 of the distance between the centers of the cameras 112 and 113.
[3] Then, the CPU 11 performs an operation of averaging the plurality of variations ΔD0 of the calculated distances between the centers of the cameras 112 and 113. Further, ΔD1 is calculated by multiplying the averaged change amount ΔD0 obtained by the interval ratio D1 / D0. Similarly, other change amounts ΔD2, ΔD3, and ΔD4 are also calculated (shift amounts in the X-axis direction of the nozzles 111a to 111d are calculated from the relative positional relationship between the cameras 112 and 113 and the nozzles 111a to 111d. To do).
In this way, the amounts of change ΔD0 to ΔD4 under a certain temperature are obtained, and when it is necessary to calculate the distances D0 ′ to D4 ′ under the same temperature, ΔD0 to ΔD4 are subtracted from D0 to D4. An operation is performed.
Note that the change amounts ΔD0 to ΔD4 are calculated for each temperature when the correction table T under each temperature is acquired, and are stored in the storage device 17 as a change amount table indicating the change amounts ΔD0 to ΔD4 under each temperature. You may memorize | store, and when need arises, you may perform the process which calculates variation | change_quantity (DELTA) D0- (DELTA) D4 only about required temperature each time.

(Correction process for Y axis direction deflection of X axis guide rail)
Based on FIG.12 and FIG.13, the correction | amendment process of the Y component in positioning of the suction nozzle 111 resulting from the Y-axis direction bending of the X-axis guide rail 121 is demonstrated. FIG. 12 is an explanatory diagram showing a correspondence relationship between the cameras 112 and 113 and the suction nozzles 111 and the recognition marks M1 to Mn. FIG. 13 is a diagram for obtaining a positional shift amount generated in the suction nozzle 111a from the positions of the two cameras 112 and 113. It is explanatory drawing of.
Such correction processing is executed when each suction nozzle 111 is positioned with respect to the receiving position, mounting position, posture detecting means 105, etc. of the electronic component during the actual mounting operation of the electronic component.

[1] First, when positioning any one of the suction nozzles (here 111a as an example) at the position coordinates (Xa, Ya), the CPU 11 detects the current temperature by a predetermined processing program.
[2] Next, the CPU 11 calculates the X coordinate of each of the cameras 112 and 113 when the suction nozzle 111a is positioned at the position coordinate (Xa, Ya).
That is, for the first camera 112, Xa−D1 is calculated, and further, the correction value ΔD1 at the current temperature is corrected, and the X component of the center position of the first camera 112 is calculated.
Similarly, for the second camera 113, correction values ΔD1 and ΔD0 at the current temperature are corrected with respect to Xa + D0−D1, and the X component at the center position of the second camera 112 is calculated.
[3] Next, the CPU 11 selects the recognition mark Mi closest to the X component of the first camera 112 obtained in [2] from the correction table T at the detected temperature, and Y of the deviation amount at the recognition mark Mi. The component YLi is read from the table T. The YLi value is the amount of misalignment in the Y-axis direction that will occur at the position of the first camera 112 in the head 110 when the suction nozzle 111a is positioned at the target position.
Similarly, the CPU 11 selects the recognition mark M (α + i) closest to the X component of the second camera 113 obtained in [2] above from the correction table T at the detected temperature, and at the recognition mark M (α + i). The Y component YR (α + i) of the deviation amount is read from the table T. The value of YR (α + i) is the amount of misalignment in the Y-axis direction that will occur at the position of the second camera 113 in the head 110 when the suction nozzle 111a is positioned at the target position.
[4] Next, the CPU 11 sucks each camera 112, 113 from the Y-axis direction shift amount at each center position of the first camera 112 and the second camera 113 in the head 110 obtained in [3]. Based on the relative positional relationship between the nozzles 111a, a Y-axis direction shift amount ΔY generated in the suction nozzle 111a is calculated.
That is, as shown in FIG. 13, the Y-axis direction deviation amount ΔY of the suction nozzle 111a can be calculated from the arrangement ratio by the following equation.
ΔY = {YR (α + i) −YLi} * {(D1 + ΔD1) / (D0 + ΔD0)}

[5] Then, the CPU 11 adds ΔY obtained in [4] above to Ya, which is the Y component of the target position coordinates of the suction nozzle 111a, so that the Y component of the target position coordinates becomes Ya + ΔY. The drive amount of the shaft motor 124 is controlled.
For the other suction nozzles 111b to 111d, the deviation amount ΔY can be similarly obtained by using the distances D2 to D4 and the change amounts ΔD2 to ΔD4.

(Correction process for Z-axis direction deflection of X-axis guide rail)
Based on FIG. 14, the X component correction process in the positioning of the suction nozzle 111 due to the Z-axis direction deflection of the X-axis guide rail 121 will be described. FIG. 14 is an explanatory diagram showing the correspondence between the first camera 112 and each suction nozzle 111 and the recognition marks M1 to Mn.
Such correction processing is executed when each suction nozzle 111 is positioned with respect to the receiving position, mounting position, posture detecting means 105, etc. of the electronic component during the actual mounting operation of the electronic component. That is, it is executed before or after the Y component correction processing described above or in parallel.

[1] First, when positioning any one of the suction nozzles (here 111a as an example) at the position coordinates (Xa, Ya), the CPU 11 detects the current temperature by a predetermined processing program.
[2] Next, the CPU 11 calculates the X coordinate of the first camera 112 when the suction nozzle 111a is positioned at the position coordinate (Xa, Ya).
That is, for the first camera 112, Xa−D1 is calculated, and further, the correction value ΔD1 at the current temperature is corrected, and the X component of the center position of the first camera 112 is calculated.
Since the processing up to this point is the same as the Y component correction processing described above, the processing can be made common and the subsequent processing can be performed separately for the Y component correction processing and the X component correction processing. good.
[3] Next, the CPU 11 selects the recognition mark Mi closest to the X component of the first camera 112 obtained in [2] from the correction table T at the detected temperature, and the amount X of the deviation amount at the recognition mark Mi. The component XLi is read from the table T. The value of XLi is the amount of deviation in the X-axis direction that will occur at the center position of the first camera 112 in the head 110 when the suction nozzle 111a is positioned at the target position.
The X-axis direction shift amount XLi of the first camera 112 can be approximated to the X-axis direction shift amount ΔX generated in the suction nozzle 111a.
[4] Accordingly, the CPU 11 adds ΔX (= XLi) obtained in [3] above to Xa which is the X component of the target position coordinate of the suction nozzle 111a, and the X component of the target position coordinate becomes Xa + ΔX. The process of adding is executed. Then, the CPU 11 controls the drive amount of the X-axis motor 123 so as to be Xa + ΔX + ΔD1 reflecting the deviation amount ΔD1 in the X-axis direction of the suction nozzle 111a due to the expansion and contraction of the head described above.
For the other suction nozzles 111b to 111d, the drive amount of the X-axis motor 123 is controlled to reflect the deviation amount ΔX and ΔD2 to ΔD4.
The camera used is not limited to the first camera 112 but may be the second camera 113.

(Effect of electronic component mounting device)
In the electronic component mounting apparatus 100, the plurality of recognition marks M <b> 1 to Mn arranged along the X-axis direction whose position coordinates are known are imaged by the two cameras 112 and 113, so that an arbitrary along the X-axis direction is obtained. The amount of deviation in the Y-axis direction that occurs at each position of the two cameras 112 and 113 can be obtained approximately. Further, since the Y-axis direction deviation amount at the nozzle 111 is obtained from the Y-axis direction deviation amount generated at two points of the head 110, the position error due to the posture and orientation variation of the head 110 can be obtained more accurately, and this is corrected. This makes it possible to mount electronic components with higher accuracy.

  Further, by capturing the plurality of recognition marks M <b> 1 to Mn with the first camera 112 provided on the same head 110 as the nozzle 111, the amount of deviation in the X-axis direction that occurs at an arbitrary camera position along the X-axis direction. Can be obtained approximately. Further, when the amount of deviation in the X-axis direction is caused by the bending of the X-axis guide rail 121 in the Z-axis direction, the amount of deviation of the imaging position in the X-axis direction is caused by the amount of deviation in the X-axis direction that occurs at the tip of the nozzle 111. The position error due to a change in the orientation and orientation of the head 110 can be obtained more accurately, and by correcting this, electronic components can be mounted more accurately.

  Furthermore, at two recognition marks Mi and M (α + i) that are separated by an equal distance from the two cameras 112 and 113, the X-axis direction of the head 110 that occurs between the two cameras from the amount of imaging position shift that occurs in the cameras 112 and 113, respectively. In addition to obtaining the amount of expansion / contraction, similarly, since the number of expansion / contraction amounts is obtained and averaged from a set of a plurality of recognition marks Mi, M (α + i), the amount of expansion / contraction of the head 110 in the X-axis direction can be obtained more precisely. It becomes possible.

  Further, the correction table T is acquired for each temperature by performing imaging at each temperature, and the imaging position deviation amount generated at each temperature is calculated as the Y-axis deviation amount, the X-axis deviation amount, or the head 110. This can be reflected in the calculation of the inter-camera distance, makes it possible to perform various misalignment corrections in consideration of the influence of temperature, and it is possible to mount electronic components more accurately at each temperature.

It is a perspective view of the electronic component mounting apparatus which is embodiment of invention. FIG. 2 is a plan view of the XY gantry disclosed in FIG. 1. It is a top view of the jig | tool board | substrate as a mark display part disclosed by FIG. It is a block diagram which shows the control system of an electronic component mounting apparatus. It is explanatory drawing which looked at XY gantry from upper direction (Z-axis direction). It is explanatory drawing which looked at the XY gantry from the front (Y-axis direction). It is explanatory drawing which shows the coordinate system developed with respect to each recognition mark of a jig | tool board | substrate. It is explanatory drawing which shows the deviation | shift amount of the recognition mark imaged from the camera center position at the time of imaging. It is explanatory drawing which shows the correction table T used for various correction | amendments. It is explanatory drawing which shows the relationship between the arrangement | positioning of each camera and each suction nozzle in a head, and each distance. It is a graph which shows the relationship between each recognition mark corresponding to two cameras, respectively, and the imaging position shift amount of the X-axis direction which arises in the said recognition mark. It is explanatory drawing which shows the correspondence of each camera and each suction nozzle, and a recognition mark. It is explanatory drawing for calculating | requiring the positional offset amount which arises in a suction nozzle from the position of two cameras. It is explanatory drawing which shows the correspondence of a 1st camera and each suction nozzle, and a recognition mark.

Explanation of symbols

10 Operation control means 11 CPU
100 Electronic Component Mounting Device 104 Base 110 Head 112 First Camera 113 Second Camera 121 X-axis Guide Rail 122 Y-axis Guide Rail 130 Jig Substrate (Mark Display Unit)
M1-Mn recognition mark

Claims (4)

A base having a substrate holder for mounting electronic components on the substrate;
A head having a nozzle for sucking an electronic component mounted on the substrate;
An X-axis guide for guiding the head along an X-axis direction parallel to the electronic component placement surface of the substrate held by the substrate holding unit;
Two Y-axis guides provided on the base for guiding the X-axis guide along the Y-axis direction parallel to the electronic component placement surface;
A mark display unit that is provided on the base side and is formed in a row and displays a plurality of recognition marks each having a known position coordinate in the XY coordinate system in which the alignment direction is the X-axis direction When,
In the nozzle position correction method for an electronic component mounting apparatus, which is disposed along the X-axis direction on the head and includes first and second cameras that image the base side.
For each of the first and second cameras, an imaging step of positioning the imaging center position at a known position coordinate in the XY coordinate system and imaging each recognition mark;
For each of the first and second cameras, a deviation amount obtaining step for obtaining an imaging position deviation amount from the imaging center based on a captured image of each recognition mark;
The imaging position shift amount in the Y-axis direction for two recognition marks close to the X coordinate of the first and second cameras when the nozzle is positioned at a target position coordinate, each camera and the nozzle, Y-axis misalignment specifying step of calculating a misalignment amount of the nozzle in the Y-axis direction from the relative positional relationship of
And a positioning step of positioning the nozzle at the target position coordinate while performing correction based on the amount of deviation in the Y-axis direction. When the nozzle is positioned at a target position coordinate, the imaging position shift amount in the X-axis direction for the recognition mark close to the X coordinate of either the first or second camera is set as the X axis of the nozzle. A first X-axis misalignment specifying step for identifying the misalignment in the direction,
2. The nozzle position correcting method for an electronic component mounting apparatus according to claim 1, wherein in the positioning step, the nozzle is positioned at the target position coordinates while performing correction based on a shift amount in the X-axis direction. A plurality of sets of two recognition marks separated by a distance substantially equal to the distance between the two cameras in the X-axis direction on the head are extracted, and the X-axis direction generated in each camera by the two recognition marks of each set is extracted. The difference between the imaging position deviation amounts is obtained, the difference between the imaging position deviation amounts in the X-axis direction of each set is averaged, and the distance between the two cameras in the X-axis direction is calculated based on the average value of the imaging position deviation amounts. An inter-camera distance specifying step for correcting
A second X-axis shift amount of the nozzle that calculates a shift amount of the nozzle in the X-axis direction from the distance between the two cameras in the X-axis direction and the relative positional relationship between the cameras and the nozzle. With a specific process,
3. The nozzle position correcting method for an electronic component mounting apparatus according to claim 1, wherein in the positioning step, the nozzle is positioned at the target position coordinates while performing correction based on the amount of deviation in the X-axis direction. In the imaging step, each recognition mark is imaged with each camera at a plurality of temperatures,
In the deviation amount acquisition step, for each camera, the imaging position deviation amount is obtained for each temperature,
Before the positioning step, a temperature detection step for detecting the temperature in the apparatus is provided,
4. The method for correcting the nozzle position of an electronic component mounting apparatus according to claim 1, wherein an amount of imaging position shift under a temperature closer to a detected temperature in the temperature detecting step is referred to.

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