JPH02244800A - Apparatus and method for mounting electronic component - Google Patents

Abstract

PURPOSE:To facilitate secure and accurate positioning of a chip component having an arbitrary shape by a method wherein a captured chip component is brought into contact with a touch sensor and the output signal of the touch sensor is processed to detect the discrepancy of the chip component and the chip component is positioned in accordance with the detection result. CONSTITUTION:The vacuum chuck 4 of a mounting part 3 is made to descend while it attracts a chip component 2 and the mounting surface of the lead on the rear of the component 2 is placed on a touch sensor s. The touch sensor 6 outputs a detected touch signal (a) corresponding to a pressure applied to the mounting surface of the lead to a touch signal processor 7. The touch signal processor 7 detects the discrepancy of the chip component 3 by comparing the touch signal (a) with a reference signal (b) outputted from an NC controller 8 and outputs correction signals (c) for the directions of an X-axis, a Y-axis and an angle theta to the NC controller 8. The NC controller 8 adds the correction values given by the correction signals (c) to the instruction values of a control program to correct the instruction values and outputs the corrected mounting direction signals of the angle theta, the X-axis and the Y-axis to the steping motor 5 of the mounting part 3 and the respective stepping motors of an X-Y table 9.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an electronic component mounting apparatus and method for mounting surface-mountable electronic components, which are components of electronic circuits, on electronic circuit boards.

Conventional electronic components for surface mounting are so-called chip components and surface mounting I.
It is an electronic component called C, and is generally placed on a circuit pattern on a flat printed circuit board, temporarily fixed, and then soldered to complete the circuit.

Conventionally, chip component mounting apparatuses in this field have sucked components with a mounting head at a supply position, as disclosed in Japanese Patent Application Laid-open No. 54-80558 and Japanese Patent Application Laid-open No. 56-24997. , mechanically regulate the position by clamping it with a positioning claw that is integrated with the mounting head or placed separately, and then
By placing the component on the printed circuit board, the component can be mounted in the correct position with respect to the printed circuit board. However, when such mechanical positioning claws are used, it is necessary to prepare several types of chucks depending on the shape and size of the chip component, which is cumbersome to handle. In addition, there was a high demand for mechanical work accuracy in order to ensure the accuracy of the mounting position of chip components on the electronic circuit board by the precision of the positioning of the mechanical positioning claws. This could lead to breakage and damage to chip components.In addition,
In the case of components such as transistors that have protruding terminals, it is not easy to clamp them.

Therefore, in order to solve such problems in mechanical position regulation, as disclosed in Japanese Patent Application Laid-open No. 164.310/1982, the position is detected from an optical image without mechanical position regulation. A method of wearing the device while correcting the position has been used, and one of the inventors of the present invention previously proposed a method of wearing the device while correcting the position.
A mounting head picks up the parts at the supply position, images the picked parts, detects positional deviation from the optical image, corrects the position of at least one of the picked parts and the printed circuit board based on the results, and places the parts. We are proposing a method.

Problems to be Solved by the Invention However, this method of correcting the position by taking an image of the component is not effective to some extent in solving the above-mentioned problems associated with mechanical position control. However, there are problems in the following points.

For example, to image the posture of a part, you can place an imaging device on the opposite side of the placement head and illuminate the part to see the part, or you can use the imaging device at the same position to illuminate the part from the placement head side. There is a way to do this, such as by looking at the image. Among these, the method of viewing images has been adopted as a method that allows easy identification of the contours of parts. However, for example, in a PLCC, the leads are in the shadow of the component body, so depending on the image, it may be difficult to distinguish the positions of the leads.Even if you can see the outline of the image, it may be difficult to distinguish between the actual circuit patterns on the printed circuit board. In some cases, it was difficult to confirm the position of the connecting part. Therefore, some problems arise, such as it being impossible to detect some parts, the exact position of the parts not being detected, the mounting accuracy not being ensured, and the types of parts that can be handled being limited.

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

Means for Solving the Problems The present invention provides an electronic component mounting apparatus that places and mounts chip components onto an electronic circuit board. a sensor, a detection means for detecting a positional deviation of a chip component by data processing of an output signal of the touch sensor, and at least one of the chip component and an electronic circuit board sucked by the vacuum chuck based on the output signal of the detection means. The present invention is characterized in that it has a correction means for correcting one position, and the chip component is released from the vacuum chuck at the corrected position and mounted on the electronic circuit board.

The present invention also provides an electronic component mounting method for positioning and mounting a chip component on an electronic circuit board, in which a chip component is captured, the captured chip component is brought into contact with a touch sensor, and the chip component is brought into contact with the chip component. The present invention is characterized in that the output signal of the touch sensor is processed to detect the positional deviation of the chip component, and the captured chip component is positioned and mounted on the electronic circuit board based on the detection result.

Operation According to the present invention, the technical means that constitutes the electronic component mounting apparatus and method operates as follows.

The vacuum chuck works to attract a chip component to its tip, and the touch sensor works to come into contact with the chip component attracted to the tip of the vacuum chuck. The detection means works to data-process the output signal of the touch sensor and detect a positional deviation from the center of the chip component or a positional deviation in an angular direction. The correction means operates to correct the position of the chip component or the electronic circuit board attracted to the vacuum chuck based on the output signal of the detection means.

The chip component is then released from the vacuum chuck at the corrected position and mounted on the electronic circuit board.

In general, chip components that are surface-mounted electronic components and printed circuit boards that are electronic circuit boards have the following characteristics.

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 protrude at least slightly from the main body of the component so as to be in contact with the flat surface of the component. Focusing on this feature, the present invention places an electronic component on a flat touch sensor while holding it in a vacuum chuck, and uses the touch sensor to check and detect the contact area of the component with respect to the coordinates. By checking the presence or absence of contact from a two-dimensional plane, it is possible to detect contact with the printed circuit board.
Detects misalignment of the connecting part, that is, the lead terminal. In this way, the position of the lead etc. of a chip component is reliably and accurately detected by the touch sensor without being limited by the type, size, shape, etc. of the chip component. It is possible to solve the problems of

Embodiments Next, the present invention will be described in more detail with reference to embodiments of the present invention based on the accompanying drawings.

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 section 1. As shown in FIG. In the component supply section 1, tapes 1 and a, in which a plurality of chip components 2 are sandwiched between two or three tapes and fixed at approximately equal intervals, are sent one pitch at a time from a tape reel 1b to a take-out section IC. Furthermore, the parts supply R1 is
The cover tape is peeled off and the chip parts are taken out one by one from the take-out opening on the top surface of the take-out part IC using a vacuum chuck 4, which will be described later. The mounting section 3 is supported movably in the transport direction of the chip component 2 and in the vertical direction by a transport device (not shown), and parts are supplied by controlling a step motor of the transport device based on a control signal from an NC control device 8, which will be described later. It reciprocates from the take-out position of the section 1 through the contact position of a touch sensor 6, which will be described later, to the mounting position of the χY table 9, which will be described later, and also moves up and down at the take-out position and the mounting position. The mounting section 3 includes a vacuum chuck 4 that sucks the chip component 2 with air, and a step motor 5 that controls the angular orientation of the vacuum chuck 4 in the angle θ direction. The vacuum chuck 4 has a tip that attracts the chip component 2, and also includes a photosensor (not shown) that detects the presence or absence of the chip component 2 at the tip.

The step motor 5 transmits its power from the Boo IJ 5 a fixed to the rotating shaft of the step motor 5 to the Boo + J 5 b fixed to the rotating shaft which rotates the vacuum chuck 4 in the angle θ direction via a bell) 5 c. By transmitting this, the vacuum chuck 4 is controlled to have an angular orientation corresponding to a control signal from an NC control device 8, which will be described later.

The electronic component mounting apparatus of the embodiment shown in FIG. 1 is equipped with a touch sensor 6, and this touch sensor 6 is connected to an XY table 9, which will be described later, on which a component mounting section 1 and an electronic circuit board 10 to be mounted are placed. It is provided at a predetermined position between the two, and comes into contact with the chip component 2 attracted to the tip of the vacuum chuck 4, and outputs a touch signal a without indicating the posture of the component.

This touch sensor 6 detects the presence or absence of contact or the strength of contact pressure two-dimensionally.As a specific example, a linear shape is formed in a shape that crosses the front and back of a sheet of pressure-sensitive conductive rubber. There are devices that detect contact by providing electrodes and detecting continuity or contact resistance at their cross points.

Pressure-sensitive conductive rubber contains gold in the base material.
When pressure is applied, the rubber deforms and the contact between the particles becomes stronger, resulting in a lower resistance. In general, it is known that materials mixed with metals and metals exhibit on-off type characteristics, and materials mixed with carbon exhibit pressure-sensitive characteristics. The thinner the pressure-sensitive conductive rubber sheet is, the better the resolution, but at present, a sheet of pressure-sensitive conductive rubber with a thickness of about 0.2 mm has a rate of 5 sheets/mm.
However, it is not sufficient to accurately detect the lead positions of all surface-mounted electronic components. Existing touch sensors can only be effectively applied to electronic products with relatively large terminals, but as the resolution of touch sensors increases, the number of electronic components to which the present invention can be applied will increase.

The touch signal processing device 7 processes the touch signal a from the touch center t-6 to measure the contact position, width, etc. of the chip component 2, and also performs NC! II':
By comparing the reference position based on @reference signal 1 from device 8 with the measured position of the measurement result, positional deviation 4 of the chip component is detected and correction signals C in the X, Y, and θ directions are output.

FIG. 2 is a block diagram showing the internal configuration of the touch signal processing device 7. As shown in FIG. As shown in FIG. 2, the touch signal processing device 7 includes a preprocessing section 11, a two-way signal conversion section 12, and an identification determination section 13. The preprocessing section 11 is
The touch signal a from the touch sensor 6 is subjected to pre-processing such as amplification, and then output to the two-way signal conversion section 12 . The binary signal conversion unit 12 is composed of a comparator or the like, and outputs a binary touch signal obtained by comparing the human touch signal with a slice level to the identification determination unit 13 .

To explain this point in more detail, the touch signal processing device 7 sequentially scans the cross points of the electrodes provided on the touch sensor 6 and detects the contact of the cross points in association with the coordinates. For sheets with on-off type characteristics, there is no need for two-way signal conversion processing such as that performed by the two-way signal conversion unit 12, but the strength of detection can be adjusted by adjusting the pressure with which the lead of the electronic component is pressed against the touch sensor. Adjust. In a sheet with pressure sensitive characteristics, that is, a resistance value that is proportional to pressure,
Requires processing of corporate bond issue. For example, this conversion into a 2-level signal is performed by setting a slice level and determining whether the electrical signal corresponding to the resistance value is 2 or lower. In this case, in addition to adjusting the pressure to press the lead of the electronic component against the touch sensor 6 to adjust the strength of detection,
Since the pressure level to be picked up can be selected by adjusting the slice level, the C identification determination unit 13, which can electrically adjust the strength of detection, associates the above-mentioned binarized signal with the coordinates and marks and records it in the memory. , Ki. The identification determination unit 13 uses a touch signal representing a pressure cover turn outputted from the touch sensor 6 due to contact of the chip component 2 accurately attracted to the reference position of the vacuum chuck 4 as a reference signal, and determines N in advance.
It is stored in the C control device 8. Then, using the computer circuit and the operation block diagram, the identification determination unit 13 performs the following:
When we receive such a reference signal from the NC control unit @8, we compare the value stored in the memory of the binarized signal just taken in,
Chip component 2 from the reference position relative to the vacuum chuck 4
A recognition calculation is performed to detect positional deviations in the directions of the X-axis, Y-axis, and angle θ, and a correction signal at for correcting the positional deviation in the directions of the X-axis, Y-axis, and angle θ is output to the NC control device 8. .

The NC control device 8 controls the entire apparatus based on a control program that instructs the component mounting order, component mounting direction, etc., the output signal of the photo sensor of the vacuum chuck 4, and the correction signal C of the evening and border redundancy processing unit 7. It is something to control. In other words, this NC! If ill device M 8 controls the step motor of the electric transmission device to move the vacuum chuck 4 of the mounting section 3 according to the control program, and sends the mounting direction control signal corrected by the correction signal C to the step motor 5 and
It is output to the Y table 9 to control the mounting direction. The XY table 9 has the electronic circuit board 10 to be mounted on its upper surface, and an and a step motor for YM positioning.

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

Mounting section 3 located at the initial setting position near component supply section 1
When the vacuum chuck 4 is moved to the position of the take-out opening of the component take-out section 1C of the component supply section 1 according to instructions from the NC control device 8, it is lowered and sucks the chip component 2 to its tip. At this time, the NC control device 8 confirms that the chip component 2 has been attracted to the tip of the vacuum chuck 4 based on the output signal of the photosensor of the vacuum chuck 4, and instructs the transfer device to continue the transfer operation. . The vacuum chuck 4 of the mounting unit 3 moves up with the chip component adsorbed at its tip, and stops above the touch sensor 6. At this position, the vacuum chuck 4 of the mounting unit 3 moves up with the chip component 2 adsorbed. Descending 4,
The lead attachment surface on the lower surface of the component 2 is placed on the touch sensor 6. The touch sensor 6 outputs a detected touch signal a corresponding to the pressure on the mounting surface of the lead of the component to the touch signal processing device 7 by scanning the electrode of the touch sensor 6 .

In this case, the mounting surface of the lead of the component is not completely one surface, but is actually irregular, and the quality is controlled to the extent that it can be mounted on a printed circuit board to form a circuit. For this reason, if the touch sensor 6 is flexible, such as a sheet of pressure-sensitive conductive rubber, it can more accurately detect the arrangement of the surface on which the lead is attached. However, if you want to get more flexibility, you can make the sheet thicker or add another layer, but this will make the sheet too thick and reduce the resolution. Furthermore, the response speed also decreases. - In this example, a sheet is added to the bottom layer of the pressure-sensitive conductive rubber sheet, and its thickness is adjusted by selecting whether it is hard or soft.

Furthermore, in the method of pressing the electronic component against the touch sensor 6, it is important 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 attach the empty vacuum chuck to the touch sensor 6.
The other method is to lower the chuck at a stop position above the chuck and determine the positional relationship by detecting the outer diameter of the chuck.Another method is to mechanically determine the positional relationship when installing each other and assemble the chuck. It is. In addition, in order to be able to accurately determine the position of the component in the present invention, the posture of the electronic component 2 attracted to the vacuum chuck 4 must be different from when it is placed on the touch sensor 6 and when it is raised again and placed on the printed circuit board. Although it is assumed that the position of the component 2 with respect to the vacuum chuck 11 has not changed since it was placed, the experimental results show that it is possible to simulate the state in which it will be placed on the printed circuit board beforehand. . It is convenient to be able to adjust the pressure with which the electronic component is pressed against the touch sensor 6, since the detection state can be adjusted over a wider range. It is simple and effective to move the vacuum chuck 4 of the mounting head up and down using an air cylinder.

In addition, in the explanation of the above-mentioned embodiment, the movement of the mounting head was stopped for one month above the predetermined position of the touch sensor, and the electronic component was pressed against the touch sensor. However, when the mounting head stops, the touch sensor may rise and touch the electronic item.Also, while the mounting head and the touch sensor move at the same speed, the vacuum chuck 4 moves up and down or the touch sensor Touch detection may be performed while moving up and down.

The touch signal processing device 7 detects the positional deviation of the chip component 2 from the touch signal a and the reference signal from the NC control device 8, and generates a correction signal C in the X-axis, Y-axis, and angle θ directions.
C output to control device 8.

The NCC control device 8 adds the correction basket indicated by the supplementary iF signal C to the command value of the control program to correct the command value. The corrected angle θ direction and mounting direction signals in the X-axis and Y-axis directions are sent to the step motors 5 and
Output to each step motor of Y table 10. Therefore, the vacuum chuck 4 of the mounting section 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 on the XY table 9. In addition, the XY table 9 is moved to the position in the X-axis and Y-axis directions to be mounted by each step motor based on the corrected mounting direction control signals in the X-axis and Y-axis directions, and is placed on the top surface. Positioning in the X-axis and Y-axis directions on the electronic circuit board 10 is performed. The vacuum chuck 4 of the mounting section, which has been moved to the mounting position on the XY table 9, is lowered and presses and mounts the chip component 2 at its tip onto the electronic circuit board 10 coated with adhesive at a predetermined position. next,
The vacuum chuck 4 lowers the air pressure level and rises by the force of a spring (single-acting air cylinder type) or by switching (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 photo sensor of the vacuum chuck 4, and transfers the vacuum chuck 4 of the mounting section 3 to the component supply section 1. Then, the next chip component 2 is mounted using the same mounting procedure.

All the chip components 2 to be mounted on the electronic circuit board 10 are mounted by repeating the above operations.

In the present invention, the contact point of the lead of the component with the printed circuit board is detected by detecting the contact with the touch sensor, but since it is grasped in a quadratic plane, the detection result is processed on a CRT etc. in the same way as in the processing of captured images. It is also possible to display it visually on a display device.

Furthermore, in the above-mentioned embodiment, the positioning of the chip component 2 was described as being performed 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. It's okay. Or
An angular positioning means may be added to the XY table 9 side.

Furthermore, although the positioning control means has been described using simple oven loop control using a step motor, closed loop control may also be used, or closed loop control may be performed using a servo motor or the like.

Furthermore, as another modification, a marker for position regulation such as magnetic paint is applied to the center of the reserved chip component, and a detector such as a magnetic sensor for detecting this is provided on or near the vacuum chuck 4. The chip component may be positioned after the pick 4 is controlled to attract the center of the chip component to reduce the displacement of the chip component.

Effects of the Invention Since the present invention has the above-described configuration, the following special effects can be obtained.

(1) Taking advantage of the fact that the chip component, which is a surface-mountable electronic component, has a structure in which the lead portion is connected to the flat surface, the chip component is connected by bringing the lead portion into contact with the flat surface of the touch sensor. Since positional deviations are detected, any type of chip component can be reliably and accurately positioned.

(2) The state of mounting on the printed circuit board and the temporary state (lead position and touch state) can be simulated in advance using a touch sensor, so based on that information, it is possible to make appropriate corrections to the mounting position and predict mounting defects in advance. It is possible to dispose of parts that have been removed, reinstall them, etc., and improve the quality of the installed parts.

(3) Most of the signal processing for touch sensors is pattern processing, which can be used in the same way as image processing. Moreover, unlike images, contact information from touch sensors does not require background processing and is not affected by lighting. Since there are no unstable factors, it is stable, more reliable lead position information can be obtained, and more accurate positioning and installation can be achieved.

[Brief explanation of drawings]

FIG. 1 is a connection diagram showing an embodiment of an electronic component mounting apparatus and method according to the present invention, and FIG. 2 is a diagram showing an internal configuration of the touch signal processing apparatus of FIG. 1. 1...Component supply section, 2...Chip components, 3...Mounting section, 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) In an electronic component mounting device that positions and mounts chip components on an electronic circuit board, a vacuum chuck that sucks the chip components, a touch sensor that comes into contact with the sucked chip components, and data on the output signal of the touch sensor are used. a detection means for detecting positional deviation of the chip component through processing;
and a correction means for correcting the position of at least one of the chip component and the electronic circuit board adsorbed to the vacuum chuck based on the output signal of the detection means, and the chip component is released from the vacuum chuck at the corrected position. An electronic circuit mounting device characterized in that the electronic circuit mounting device is mounted on an electronic circuit board. (2) In an electronic component mounting method that positions and mounts a chip component on an electronic circuit board, the chip component is captured,
The captured chip component is brought into contact with a touch sensor, and the output signal of the touch sensor obtained by contacting the chip component is data processed to detect the positional shift of the chip component, and the captured chip component is detected based on the detection result. An electronic component mounting method characterized by positioning and mounting an electronic component on an electronic circuit board.