JPH07120875B2 - Electronic component mounting apparatus and method thereof - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic component mounting apparatus and method for mounting a surface mounting electronic component, which is a component of an electronic circuit, on an electronic circuit board.

Conventional technology Electronic components for surface mounting are so-called chip components and surface mounting ICs.
This is an electronic component generally called a device that is placed on a circuit pattern on a flat printed circuit board and temporarily fixed and then soldered to complete the circuit.

Conventionally, in the chip component mounting apparatus in such a field, as disclosed in JP-A-54-80558 and JP-A-56-24997, components are sucked by a mounting head at a supply position, The position is mechanically regulated by sandwiching it between the mounting head and a positioning claw that is separate or separately mounted, and then mounted on the printed circuit board so that the component can be mounted in the correct position on the printed circuit board. There is. However,
If such a mechanical positioning claw is used, it is necessary to prepare several kinds of chucks depending on the difference in the shape and size of the chip component, which is troublesome to handle.
Further, there has been an increasing demand for machining accuracy in order to secure the mounting position accuracy of the chip component on the electronic circuit board due to the positioning accuracy of the mechanical positioning claw. Further, the mechanical positioning of the components sandwiches the components, which causes damage or damage to the chip components. Besides, in the case of a component such as a transistor having a protruding terminal, it is not easy to sandwich it.

Therefore, in order to solve such a problem in the mechanical position regulation, as disclosed in JP-A-57-164310, the position is detected from the optical image and the position is detected without performing the mechanical position regulation. A method of mounting with correction is being carried out, and one of the inventors of the present invention was previously disclosed in
As disclosed in Japanese Laid-Open Patent Publication No. 152100/1982, a component is sucked by a mounting head at a supply position, an image of the sucked component is picked up, a positional shift is detected from an optical image, and as a result, the sucked component and the printed circuit board are It proposes a method in which at least one position is corrected and then placed.

However, the method of correcting the position by picking up the image of the part as described above has a certain effect in solving the above-mentioned problems associated with the mechanical position regulation. Although it works, there are problems in the following points.

For example, as a method of imaging the posture of a component, an imaging device is arranged on the opposite side of the mounting head to illuminate the component to see the image, or the imaging device illuminates the component at the same position from the mounting head side. There is a method of seeing the image of. Above all, the method of viewing the image has been adopted as a method for easily distinguishing the contours of the parts. However, for example, in PLCC, since the lead part becomes a shadow of the component body, it is difficult to distinguish the lead positions depending on the image.For example, the outline of the image can be confirmed, but the circuit pattern on the printed circuit board is actually confirmed. In some cases, it was difficult to confirm the position of the part to be connected to and connected to. Therefore, there are inconveniences such that some parts cannot be detected, the accurate position cannot be detected, the mounting accuracy cannot be secured, and the types of parts that can be handled are limited.

An object of the present invention is to provide an electronic component mounting apparatus and method that can solve such problems.

Means for Solving the Problems The present invention is an electronic component mounting apparatus for adsorbing a chip component supplied from a component supply unit by a vacuum chuck and pressing the chip component onto a positioned electronic circuit board to mount the chip component on the vacuum chuck. Touching the lead terminal by sequentially scanning the flat touch sensor that touches all the contact portions of the lead terminals of the held chip component on the electronic circuit board, and the cross points of the electrodes provided on the touch sensor. Touch signal processing means for detecting the positional deviation of the chip component with respect to the vacuum chuck and outputting a positional deviation correction signal, and control for correcting the relative position of the vacuum chuck and the electronic circuit board. And means,
The relative position of the chip component held by the vacuum chuck and the electronic circuit board is corrected based on the correction signal obtained by the touch signal processing means, and then the chip component is pressed and mounted. And

Further, the present invention is an electronic component mounting method for capturing a chip component supplied from a component supply unit, and pressing and mounting the chip component on an electronic circuit board that has been positioned, wherein an electronic circuit of a lead terminal of the captured chip component. Data is obtained by aligning touching portions on the substrate, touching a flat touch sensor, sequentially scanning cross points of electrodes provided on the touch sensor, and detecting the touch of the lead terminal in association with two-dimensional coordinates. By processing, a positional deviation correction signal indicating a positional deviation of the captured chip component from the capture reference position is generated, and the relative position between the captured chip component and the electronic circuit board is based on the positional deviation correction signal. The target position is corrected and then the chip component is pressed and mounted.

Operation According to the present invention, the technical means constituting the electronic component mounting apparatus and the method thereof operate as follows. The vacuum chuck works to attract the chip component to its tip, and the touch sensor works to contact the chip component attracted to the tip of the vacuum chuck. The detection means performs data processing on the output signal of the touch sensor to detect the positional deviation of the chip component from the center and the angular positional deviation. The correction means works so as to correct the position of the chip component or the position of the electronic circuit board sucked by the vacuum chuck, based on the output signal of the detection means. Then, the chip component is released from the vacuum chuck at the corrected position and mounted on the electronic circuit board.

Generally, a chip component, which is an electronic component for surface mounting, and a printed circuit board, which is an electronic circuit board, have the following features.
That is, the printed circuit board has a flat plate shape, and the connection portion of the lead of the component to the printed circuit board circuit pattern is made to project at least slightly from the main body of the component so as to be in contact with the plane. Focusing on this feature, the present invention places the electronic component on the flat touch sensor while adsorbing the electronic component by the vacuum chuck, and confirms and detects the contact portion of the component with respect to the coordinates by the touch sensor. The contact with the printed circuit board by grasping the presence or absence of contact on the second plane.
The displacement of the connecting part, that is, the lead terminal is detected. In this way, the positions of the leads of the chip parts are
It is not limited to the type, size, shape, etc. of the chip component,
As it is detected accurately by the touch sensor,
According to the present invention, the above-mentioned conventional problems can be solved.

EXAMPLES Next, the present invention will be described in more detail with reference to the accompanying drawings with reference to the examples of the present invention.

FIG. 1 is a connection diagram showing an embodiment of an electronic component mounting apparatus and method according to the present invention. As schematically shown in FIG. 1, the electronic component mounting apparatus of this embodiment includes a component supply unit 1. To the component supply unit 1, a tape 1a having a plurality of chip components 2 sandwiched between two or three tapes and fixed at substantially equal intervals is sent from the tape reel 1b to the take-out unit 1c by one pitch. Further, the component supply unit 1 is provided so that the cover tape can be peeled off and the chip components can be taken out one by one by the vacuum chuck 4 described later from the taking-out port on the upper surface of the taking-out unit 1c. The mounting unit 3 is supported by a transfer device (not shown) so as to be movable in the transfer direction and the vertical direction of the chip component 2, and the parts are supplied by the control of a step motor of the transfer device based on a control signal from an NC control device 8 described later. While reciprocating from the take-out position of the unit 1 through the contact position of the touch sensor 6 described later to the mounting position of the XY table 9 described later, at the take-out position and the mounting position,
Move up and down. The mounting portion 3 includes a vacuum chuck 4 for sucking the chip component 2 with air and an angle θ of the vacuum chuck 4.
A stepper motor 5 for controlling the angular orientation of the direction. The vacuum chuck 4 has a tip end portion for sucking the chip component 2 and a photo sensor (not shown) for detecting the presence or absence of the tip component 2 at the tip end portion. The step motor 5 is a pulley fixed to the rotation shaft of the step motor 5.
By transmitting the power from 5a to the pulley 5b fixed to the rotary shaft that rotates the vacuum chuck 4 in the angle θ direction via the belt 5c, the angular orientation corresponding to the control signal from the NC control device 8 described later is obtained. The vacuum chuck 4 is controlled.

The electronic component mounting apparatus according to the embodiment shown in FIG. 1 includes a touch sensor 6, and the touch sensor 6 mounts the component mounting portion 1 and an electronic circuit board 10 to be mounted, which will be described later.
It is provided at a predetermined position between the XY table 9 and the tip part of the vacuum chuck 4 and comes into contact with the chip part 2 to output a touch signal a indicating the attitude of the part.

This touch sensor 6 detects the presence or absence of contact or the strength of contact pressure in a two-dimensional manner. As a specific example, the front and back of a pressure-sensitive conductive rubber sheet are linearly crossed with each other. There is a method in which the contact is detected by providing the electrode of and the conduction of the cross point or the contact resistance is detected. Pressure-sensitive conductive rubber is a silicon rubber matrix in which conductive particles such as metal and carbon are dispersed.When pressure is applied, the rubber deforms and the contact between particles becomes stronger.
As a result, the resistance is lowered. It is generally known that a mixture of metals exhibits on-off type characteristics, and a mixture of carbon exhibits pressure-sensitive characteristics. The thinner the pressure-sensitive conductive rubber sheet is, the more the resolution is improved, but at present, it is only about 5 mm / mm with a thickness of about 0.2 mm to 10 electrodes / mm with a thickness of about 0.1 mm. It is not satisfactory to accurately detect the lead position of the surface mounting electronic component. The existing touch sensor can be effectively applied only to an electronic component having a relatively large terminal, but as the resolution of the touch sensor is improved, the present invention should be applied to increase the effective electronic component.

The touch signal processing device 7 measures the contact position and width of the chip component 2 by performing signal processing on the touch signal a from the touch sensor 6, and at the same time determines the reference position based on the reference signal b from the NC control device 8. The positional deviation of the chip component is detected by comparing the measurement result with the measurement position, and the correction signal c in the X, Y, and θ directions is output. FIG. 2 is a block diagram showing an internal configuration of the touch signal processing device 7. As shown in FIG. 2, the touch signal processing device 7
Is composed of a preprocessing unit 11, a binary signal conversion unit 12, and an identification determination unit 13. The preprocessing unit 11 includes the touch sensor 6
Pre-processing such as amplifying the touch signal a from
Output to the value signal conversion unit 12. The binary signal conversion unit 12 is composed of a comparator or the like, and compares the input touch signal with the slice level, and outputs the binary touch signal to the identification determination unit 13.

Explaining this point in detail, the touch signal processing device 7
Scans the cross points of the electrodes provided on the touch sensor 6 sequentially and detects the contact of the cross points in association with the coordinates. The on-off type sheet does not require the binary signal processing such as the binary signal conversion unit 12, but the strength of the detection can be improved by adjusting the pressure of pressing the lead of the electronic component against the touch sensor. Adjust. A sheet having a pressure-sensitive characteristic, that is, a resistance value proportional to the pressure, needs a binary signal conversion process by the binary signal conversion unit 12. For example, this binary signal conversion is performed by setting a slice level and determining whether the electrical signal corresponding to the resistance value is above or below it. In this case, the pressure level to be picked up can be selected by adjusting the slice level in addition to adjusting the pressure of pressing the lead of the electronic component against the touch sensor 6 to adjust the detection strength. The strength can be adjusted. The identification determination unit 13 stores the binarized signal described above in a memory in association with the coordinates. The identification determination unit 13 uses the touch signal representing the pressure pattern output from the touch sensor 6 due to the contact of the chip component 2 that is accurately attracted to the reference position of the vacuum chuck 4 as a reference signal, and then uses the NC controller 8 in advance.
To remember. Then, by the computer circuit and the operation program, the identification determination unit 13 compares such a reference signal b from the NC control device 8 with the stored value of the binarized signal that has just been fetched in the memory, and the vacuum is determined. A recognition calculation is performed to detect the positional deviation of the chip component 2 in the directions of the X axis, the Y axis and the angle θ from the reference position with respect to the chuck 4, and X is calculated.
A correction signal c for correcting the positional deviation in the directions of the axis, the Y axis and the angle θ is output to the NC control device 8.

The NC control device 8 controls the entire device based on a control program for instructing the mounting order of components, the mounting direction of components, etc., the output signal of the photosensor of the vacuum chuck 4 and the correction signal c of the touch signal processing device 7. is there. That is, the NC control device 8 controls the step motor of the carrying device according to the control program to control the vacuum chuck 4 of the mounting unit 3.
Is moved and the mounting direction control signal corrected by the correction signal c is output to the step motor 5 and the XY table 9 to control the mounting direction. The XY table 9 mounts the electronic circuit board 10 to be mounted on the upper surface, and positions the X-axis and the Y-axis of the chip component based on the mounting direction control signal from the NC control device 8, respectively. It has a step motor for axis positioning.

Next, the operation of the apparatus of this embodiment will be described in order.

The mounting unit 3 located at the initial setting position near the component supply unit 1
When the vacuum chuck 4 moves to the position of the take-out port of the component take-out section 1c of the component supply section 1 according to the instruction of the NC control device 8, the vacuum chuck 4 descends and sucks the chip part 2 at the tip. At this time, the NC control device 8 uses the output signal of the photosensor of the vacuum chuck 4 to attach the chip component 2 to the tip of the vacuum chuck 4.
After confirming that is adsorbed, the transfer device is instructed to continue the transfer operation. The vacuum chuck 4 of the mounting portion 3 moves up with the tip part adsorbing the chip component, and stops at a position above the touch sensor 6. At this position, the mounting unit 3 lowers the vacuum chuck 4 while sucking the chip component 2 to
The mounting surface of the lead on the lower surface of is placed on the touch sensor 6. The touch sensor 6 outputs a detected touch signal a corresponding to the pressure of the mounting surface of the lead of the component to the touch signal processing device 7 by scanning the electrodes of the touch sensor 6. In this case, the lead mounting surface of the component is not completely one surface, but is actually uneven. The quality is controlled to the extent that it can be mounted on a printed circuit board to form a circuit. Therefore, if the touch sensor 6 is flexible like a sheet of pressure-sensitive conductive rubber, it is possible to detect the placement of the lead mounting surface more accurately. However, if you want to gain a lot of flexibility, you can either increase the thickness of the sheet or add a sheet to another layer.However, if you do this, the sheet becomes too thick, the resolution decreases, and the response speed also increases. descend. In one example, a sheet is added to the lower layer of the pressure-sensitive conductive rubber sheet, and the thickness thereof is adjusted by selecting hard and soft.

Further, what is important in the method of pressing the electronic component against the touch sensor 6 is to first determine the relationship between the center of the vacuum chuck 4 and the reference position of the touch sensor 6. One method is to lower an empty vacuum chuck at a stop position on the touch sensor 6 to detect the outer diameter of the chuck and determine the positional relationship. The mechanical relationship is to determine the positional relationship before assembly. In addition, in order to accurately determine the position of the component in the present invention, the posture of the electronic component 2 sucked by the vacuum chuck 4 rises again when the electronic component 2 is placed on the touch sensor 6 and is placed on the printed circuit board. It is premised that the position of the component 2 with respect to the vacuum chuck 4 does not change when placed. However, according to the result of the experiment, the state of placing on the printed circuit board can be simulated before that. It is convenient that the pressure for pressing the electronic component against the touch sensor 6 can be adjusted so that the detection state can be adjusted more widely. It is simple and effective to raise and lower the vacuum chuck 4 of the mounting head with an air cylinder.

In the description of the above-described embodiment, the movement of the mounting head is temporarily stopped on the predetermined position of the touch sensor, and the electronic component is pressed against the touch sensor, but the present invention is not limited to this. Alternatively, when the mounting head stops, the touch sensor may move up to touch the electronic component. Further, while the mounting head and the touch sensor move at the same speed, the vacuum chuck 4 is moved up and down or the touch sensor is moved up and down. Touch detection may be performed while moving.

The touch signal processing device 7 uses the touch signal a and the NC control device 8
The positional deviation of the chip component 2 is detected from the reference signal b from the above, and the correction signal c in the X-axis, Y-axis and angle θ direction is output to the NC control device 8. The NC controller 8 uses this correction signal c
The correction value indicated by is added to the command value of the control program to correct the command value. Corrected angle θ direction and X axis, Y
A mounting direction signal in the axial direction is output to the step motor 5 of the mounting unit 3 and each step motor of the XY table 10. Therefore, the vacuum chuck 4 of the mounting portion 3 is controlled by the step motor 5 to have an angular orientation corresponding to the mounting direction control signal in the angle θ direction, and is further moved to the mounting position of the XY table 9. Also, the XY table 9 has the corrected X
Based on the mounting direction control signals in the axis and Y-axis directions, the step motors move to positions in the X-axis and Y-axis directions to be mounted, and the X-axis and Y-axis on the electronic circuit board 10 placed on the upper surface portion. Position in the axial direction. XY table 9
The vacuum chuck 4 of the mounting portion that has moved to the mounting position descends and presses and mounts the tip part 2 on the electronic circuit board 10 on which the adhesive is applied at a predetermined position. next,
The vacuum chuck 4 lowers the pressure level of air and rises by the force of a spring (single-acting air cylinder type) or switches and rises (double-acting air cylinder type). At this time, the NC control device 8 confirms that the chip component 2 is mounted on the electronic circuit board 10 based on the output signal of the photosensor of the vacuum chuck 4, and then the vacuum chuck 4 of the mounting part 3 is connected to the component supply part 1. After moving to the position of the ejection port, the next chip component 2 mounting operation is performed by the same mounting procedure. The above operation is repeated to mount all the chip components 2 to be mounted on the electronic circuit board 10.

In the present invention, the contact location of the lead of the component with the printed circuit board is detected by detecting the contact by the touch sensor. However, since it is grasped in a quadratic plane, the detection result is displayed on a CRT or the like like the captured image processing. It is also possible to display it on the device in a form that can be visually observed.

Furthermore, in the above-described embodiment, the chip component 2 is positioned by the XY table 9 and the vacuum chuck 4, but the present invention is not limited to this, and all positioning is performed on the vacuum chuck 4 side. May be. Or XY
An angular positioning means may be added to the table 9 side.

Further, although the positioning control means has been described as a simple open loop control by a step motor, it may be closed loop control or closed loop control by a servo motor or the like.

Furthermore, as another modified example, a position regulating marker such as magnetic paint is applied to the center of the chip component in advance, and a detector such as a magnetic sensor for detecting the marker is provided in or near the vacuum chuck 4, and the vacuum chuck The position of the chip component may be determined after controlling the position of the chip component 4 so as to suck the center of the chip component to reduce the displacement of the chip component.

EFFECTS OF THE INVENTION Since the present invention is configured as described above, the following special effects can be obtained.

(1) Utilizing the fact that the chip component, which is an electronic component for surface mounting, has a structure in which the lead portions are connected to a flat surface. Since the positional deviation is detected, the chip components of any type can be reliably and accurately positioned.

(2) Since the mounting state (lead position and touch state) on the printed circuit board can be simulated by a touch sensor in advance, appropriate correction of the mounting position and prediction of mounting failure can be predicted based on the information. The parts can be discarded, the mounting can be redone, and the mounting quality can be improved.

(3) Most of the signal processing of the touch sensor is the pattern processing, and the same processing as the image processing can be diverted. Moreover, unlike the image, the contact information of the touch sensor does not need the background processing, and the influence of the illumination is exerted. Since there is no such unstable element, stable and more reliable lead position information can be obtained, and more accurate positioning and mounting can be performed.

[Brief description of drawings]

FIG. 1 is a connection diagram showing an embodiment of an electronic component mounting device and method according to the present invention, and FIG. 2 is a diagram showing an internal configuration of the touch signal processing device of FIG. 1 ... Component supply unit, 2 ... Chip component, 3 ... Mounting unit, 4 ... Vacuum chuck, 5 ... Step motor, 6 ... Touch sensor, 7 ... Touch signal processing device, 8 ... NC control Device 9 ... XY table, 10 ... Electronic circuit board.

Claims (2)

[Claims] 1. An electronic component mounting apparatus for sucking a chip component supplied from a component supply unit by a vacuum chuck and pressing the chip component onto a positioned electronic circuit board to mount the chip component on the electronic circuit board. A planar touch sensor that touches all the contact portions of the lead terminals on the electronic circuit board and a cross point of electrodes provided on the touch sensor are sequentially scanned to associate the touch of the lead terminals with two-dimensional coordinates. A touch signal processing unit that detects a positional shift of the chip component with respect to the vacuum chuck and outputs a positional shift correction signal; and a control unit that corrects the relative position of the vacuum chuck and the electronic circuit board, Based on the correction signal obtained by the touch signal processing means, the phase of the chip component held on the vacuum chuck and the electronic circuit board An electronic component mounting apparatus, characterized in that the chip component is pressed and mounted after the relative position is corrected. 2. An electronic component mounting method for capturing and mounting a chip component supplied from a component supply unit on a positioned electronic circuit substrate, the electronic circuit substrate of a lead terminal of the captured chip component. Data processing is performed by aligning the parts that come in contact with the top, touching a flat touch sensor, and sequentially scanning the cross points of the electrodes provided on the touch sensor to detect the touch of the lead terminal in association with two-dimensional coordinates. By doing so, a positional deviation correction signal indicating the positional deviation of the captured chip component from the capture reference position is generated, and the relative position between the captured chip component and the electronic circuit board is based on the positional deviation correction signal. An electronic component mounting method, characterized in that the chip component is pressed and mounted after the position is corrected.