JPH1051195A - Mounting apparatus for electronic component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a mounting apparatus by which the tact time of a mounting operation can be shortened when a component whose three-dimensional shape inspection such as a lead levitation inspection or the like is required is mounted by a method wherein height data, in every line, obtained by a line scanning operation by means of a laser beam is used as three-dimensional image data and an image processing operation is executed to the three-dimensional image data. SOLUTION: A component 2 is moved on a 3-D sensor 8, a laser beam 44 is scanned in a direction perpendicular to the movement of the component 2, the laser beam 44 is projected on the bottom face of the component 2, the reflection of the laser beam 44 is coupled to a semiconductor position detecting element, the output of the semiconductor position detecting element is height-computed sequentially, and the three-dimensional image of the component 2 is fetched by an image memory 35. At this time, especially when a lead 45 is levitated, height data 46 with reference to the lead 45 becomes a large value as compared with that of other leads 45. By comparing the data, the three-dimensional shape inspection such as the lead levitation inspection of the lead 45 can be performed. Consequently, the tact time of a mounting operation shortened when the component 2 is mounted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic component mounting apparatus for automatically mounting electronic components on a printed circuit board, a liquid crystal display, a plasma display panel substrate, or the like.

[0002]

2. Description of the Related Art Conventionally, in an electronic component mounting apparatus, when mounting an electronic component such as a QFP connector having a narrow lead pitch and a narrow lead width, the lead floating of the component must be performed before the electronic component is mounted on a printed circuit board. Generally, automatic inspection is performed.

FIG. 9 is a mounting process diagram of a conventional electronic component mounting apparatus. Many conventional electronic component mounting apparatuses mount an electronic component having a narrow lead pitch through a series of processes as shown in FIG.

That is, in the process shown in FIG. 9A, the electronic component 2 stored in the tray 3 is picked up by the head unit 7 of the mounting apparatus. In the step shown in FIG. 9B, an image of the sucked electronic component 2 is picked up by the positioning camera 47 and is positioned by using the image processing device to obtain the positioning information.

In the step shown in FIG. 9 (c), using the positioning information obtained in the step shown in FIG. 9 (b), the electronic component 2 is inspected for lead floating by a transmission type lead floating sensor 48, or The leading edge of the lead or a shadow of the leading end is imaged by the lead lifting inspection camera 49, and the lead lifting inspection is performed by the image processing apparatus.

If there is no abnormality in the result of this inspection, FIG.
In a step shown in FIG. 9D, correction calculation of the printed board 9 and the mounted electronic component 2 is performed based on the positioning information obtained in the step of FIG. Attach in position.

[0007]

However, in the above-described conventional electronic component mounting apparatus, when a component is mounted through a series of processes performed according to the steps shown in FIG.
The camera 47 for positioning in the step shown in FIG.
The lead floating sensor 48 and the lead floating inspection camera 49 in the step shown in FIG. 9C are physically separated from each other, and are drawn by using the positioning information obtained in the step shown in FIG. Since it is necessary to mechanically position the components in the process shown in FIG. 9 (c), the processes in each process cannot be parallelized, and are necessarily serial processes. Movement, stop, vertical movement, etc. are required.

As a result, the processing time of the steps shown in FIGS. 9 (b) and 9 (c), including the operation time of moving, stopping, moving up and down, etc. of the mounted component, is directly useful for the entire mounting time. Therefore, there is a problem that the entire mounting time is increased by the operation time.

[0009] In addition, as shown in FIG.
When the lead floating is inspected by the transmission type lead floating sensor 48, it is necessary to individually scan four sides of the physically mounted component, and the processing time for this is usually about 1 to 3 seconds.
This processing time causes a longer mounting time of such components. This is a significant disadvantage particularly when a large number of QFPs and connectors are mounted.

[0010] On the other hand, when the lead floating inspection is performed using the lead floating inspection camera 49, the lead floating inspection is performed in the same manner as described above due to the focusing of the camera and the capture of divided images due to lack of resolution. It takes a long time, and the problem of mounting tact time also occurs.

SUMMARY OF THE INVENTION In view of the above problems, the present invention can reduce the mounting tact time when mounting a component that requires a three-dimensional shape inspection such as lead floating inspection, Pixel size (resolution) in both horizontal and vertical directions can be guaranteed for an image.
An object of the present invention is to provide an electronic component mounting apparatus that can flexibly cope with high-speed and high-resolution (high-precision) mounting of a narrow-pitch component such as a connector or a connector.

[0012]

An electronic component mounting apparatus according to the present invention includes a control unit for performing image processing on three-dimensional image data of an electronic component, and moves the control unit over three-dimensional image capturing means. A three-dimensional image of the electronic component obtained by laser light scanning in a direction perpendicular to the moving direction of the electronic component is loaded into an image memory, and the operating speed of the moving device for moving the electronic component is configured to be constant. It is possible to reduce the mounting tact time when mounting components that need to be inspected for three-dimensional shapes such as lead floating inspection. Pixel size (resolution) in both directions can be guaranteed, and when mounting narrow-pitch components such as QFPs and connectors, the mounting speed and resolution (high precision) It is possible to flexibly.

[0013]

An electronic component mounting apparatus according to a first aspect of the present invention provides a component supply unit that supplies an electronic component to be mounted on a substrate, a head unit that holds the electronic component, and moves the head unit. A head unit moving device, a three-dimensional image capturing unit disposed below the moving area of the head unit, and performing line scanning by laser light to obtain height data for each line, and a three-dimensional image capturing unit. And an image memory that stores the height data as three-dimensional image data, and a control unit that performs image processing on the three-dimensional image data of the electronic component.

According to this configuration, the three-dimensional image of the mounted component is captured by the three-dimensional image capturing means, and image processing is performed on the three-dimensional image, whereby positioning of the electronic component and three-dimensional image processing are performed.
Inspection of a dimensional part shape can be performed simultaneously.

[0015] In the prior art, as shown in FIG. 9, the positioning by the camera and the three-dimensional shape inspection such as the lead floating inspection are serial (separate processes).
As shown in FIG. 10, the simultaneous processing of the positioning and the three-dimensional inspection is enabled, and as a result, the component mounting time is significantly reduced. Here, the present invention and FIG.
The differences from the prior art shown in FIG.

In FIG. 10, reference numeral 2 denotes an electronic component to be mounted, 3 denotes a tray on which the electronic component 2 is placed, 7 denotes a head for moving the electronic component 2, and 8 denotes a three-dimensional image.
A three-dimensional sensor 9 as a three-dimensional image capturing means is a printed circuit board on which the electronic component 2 is mounted.

In the step shown in FIG.
Is picked up (adsorbed) from the tray 3 by the head unit 7. In the step shown in FIG. 10B, when the electronic component 2 moves on the three-dimensional sensor 8 as the head unit 7 moves, the moving operation and the scanning by the laser light 8a emitted from the three-dimensional sensor 8 are performed. The three-dimensional image of the bottom surface 2a of the electronic component 2 being sucked and moved is taken into the image memory M1 in the image processing device G1, and the image is processed to perform positioning and three-dimensional shape inspection of the electronic component 2. And do both. In the step shown in FIG. 10C, the electronic component 2 is mounted on the printed circuit board 9 based on the positioning information obtained by the image processing of the image processing device G1.

According to a second aspect of the present invention, there is provided an electronic component mounting apparatus, wherein the main control unit according to the first aspect stores, in an image memory, a three-dimensional image obtained by laser light scanning in a direction perpendicular to the moving direction of the electronic component. It is characterized in that the operation speed of the head moving device for moving the electronic component is kept constant while taking in the electronic component.

According to this configuration, with respect to the electronic component mounting apparatus according to the first aspect, the operating speed of the moving device is fixed, and unnecessary stoppage of components during the mounting operation before and after the moving device is eliminated. Enables shortening of tact time during mounting operation.

According to a third aspect of the present invention, there is provided an electronic component mounting apparatus for moving an electronic component to be mounted on a substrate, a polygon mirror disposed below the moving device, and the polygon mirror. A semiconductor laser that emits a laser beam, one or more position detecting elements disposed around the polygon mirror, and an image of the laser light that strikes the bottom surface of the electronic component on the position detecting element. An imaging lens for causing the semiconductor laser to be disposed such that the laser light is reflected by the rotating polygon mirror and hits the bottom surface of an electronic component passing over the polygon mirror, and the semiconductor laser is arranged by the moving device. Based on the passing operation of the electronic component on the polygon mirror and the laser scanning generated by the rotational movement of the polygon mirror, Position capture a three-dimensional image of the electronic component detecting device can be obtained by calculating the data to be output to the image memory, and performs positioning with the parts shape inspection of the electronic component in the three-dimensional image.

According to this configuration, the three-dimensional image of the electronic component is captured by the three-dimensional image capturing means including the polygon mirror, the semiconductor position detecting element, and the semiconductor laser, and the positioning of the electronic component and the three-dimensional shape are performed. Inspection and inspection can be performed simultaneously.

According to a fourth aspect of the present invention, in the electronic component mounting apparatus according to the third aspect, the electronic component moving device receives a rotation amount signal of a polygon mirror and a movement amount detection circuit for calculating a movement amount of the electronic component moving device from a reference position. A rotation amount detection circuit that calculates a rotation amount of the polygon mirror from a reference position; and a first comparison circuit that compares a movement amount of the electronic component moving device with a rotation amount of the polygon mirror. As a result of comparison in the circuit, if the difference between the two is within an allowable range, the data recorded in the image memory is treated as valid data, and if the difference is outside the allowable range, the data is invalidated. .

According to a fifth aspect of the present invention, in the electronic component mounting apparatus according to the third or fourth aspect, a moving speed detection circuit for calculating a moving speed of the electronic component moving device at each time, and a rotation amount signal of a polygon mirror are provided. And a second comparison circuit for comparing the rotation speed of the polygon mirror with the rotation speed of the electronic component moving device. , Second
As a result of comparison by the comparison circuit, if the difference between the two is within an allowable range, the data recorded in the image memory is treated as valid data, and if the difference is outside the allowable range, the data is invalidated. And

According to this configuration, the moving amount of the moving device for moving the electronic component to be mounted and the rotating amount of the polygon mirror, or one or both of the moving speed of the moving device and the moving speed of the polygon mirror are monitored in a circuit. The three-dimensional image captured by the scanning movement of both the moving device and the polygon mirror that are independently moving is secured (the image aspect ratio is matched without partial distortion), and the three-dimensional image is processed. Guarantees the accuracy and reliability of the operation results obtained by

According to a sixth aspect of the present invention, there is provided the electronic component mounting apparatus according to the third to fifth aspects, further comprising a clock speed changing means for changing a speed of a basic clock for capturing the three-dimensional image. On the other hand, when a high resolution is required, the basic clock is increased by the clock speed changing means, the moving speed of the electronic component moving device is reduced, and a high speed is required for capturing the three-dimensional image. Is characterized in that the basic clock is reduced by the clock speed changing means and the moving speed of the electronic component moving device is increased.

According to this configuration, the speed (frequency) of the basic clock for capturing the three-dimensional image is changed, and at the same time, the moving speed of the moving device for moving the object is accelerated / decelerated to operate. When locating electronic components and performing three-dimensional component shape inspection according to the mounted components without impairing the normality of the components, the resolution is improved when importance is placed on the accuracy of positioning and inspection, and when importance is placed on speed, Switching to improve the scanning speed is easily realized.

According to a seventh aspect of the present invention, in the electronic component mounting apparatus according to any one of the third to sixth aspects, the electronic component is mounted at a time from when the electronic component is located at the image capturing start position to when it is located at the laser beam scanning start position. Calculating means for calculating a moving distance of the electronic component, and positioning the electronic component on a three-dimensional image in consideration of the distance calculated by the calculating means.

According to this configuration, if the components are positioned based on the calculation result calculated by the calculation means, it is possible to prevent a decrease in positioning accuracy due to a variation in timing shift, and to perform positioning. Can be performed with higher accuracy.

Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings. FIG. 1 shows an electronic component mounting apparatus according to an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a mounting apparatus main body of an electronic component mounting apparatus, 2 denotes an electronic component (hereinafter abbreviated as a component) mounted by the present apparatus, 3 denotes a tray on which the component 2 is mounted, and 4 denotes a tray mounted on the tray 3. Tray supply unit as a component supply unit that automatically supplies the component 2 that has been mounted,
A head section 5 for sucking and mounting the head section 7 moves the head section 7 in the x-axis direction, and a robot on the x-axis side (hereinafter abbreviated as an x-axis robot) constituting a part of the xy robot;
6a and 6b constitute a part of the xy robot that moves the head unit 7 in the y-axis direction together with the x-axis robot 5.
Axis side robot (hereinafter abbreviated as y axis robot), 8
Denotes a three-dimensional (hereinafter abbreviated as 3D) sensor, which captures a height image of the component 2. 9 is a printed circuit board on which the component 2 is mounted.

The component 2 placed on the tray 3 is
When moving along the x-axis robot 5 on the 3D sensor 8 sucked by the 3D sensor 8, the 3D sensor 3
A D (height) image is captured. The (height) image obtained by the 3D sensor 8 is subjected to software processing to perform 3D shape inspection such as positioning of the component 2 and lead floating, and the component 2 is positioned at a predetermined position on the printed circuit board 9 according to the positioning information. Be attached.

FIG. 2 shows the capture of a three-dimensional image.
In FIG. 2, reference numeral 2 denotes a component moving by the operation of the x-axis robot 5, reference numeral 8 denotes a three-dimensional sensor, reference numeral 44 denotes a laser beam scanned by a polygon mirror, and reference numeral 45 denotes one of the leads of the component 2; Leads 46 that are bent (floating) on the opposite side are height data when the lead 45 is imaged by the 3D sensor 8.

FIGS. 2A to 2C show that the component 2 is moved over the 3D sensor 8 and the laser light 44 is scanned in a direction perpendicular to the movement of the component 2 so that the laser light 4
4 is projected, the reflection of the laser light 44 is imaged on the semiconductor position detecting element, and the output of the semiconductor position detecting element is sequentially subjected to height calculation, whereby the three-dimensional image of the component 2 is stored in the image memory 35. This shows a state in which capture is performed.

The data captured in each horizontal row of the image memory 35 is stored in the 3D sensor 8 of the object (in this case, the lead of the component 2 or the package portion) on each of the laser scanning lines whose height has been calculated by the above method. The height data from the side, X
-It becomes like a Y sectional view.

FIGS. 2D to 2F show the state of the image memory 35 when the component 2 has finished passing over the 3D sensor 8. In particular, if the lead 45 is floating, In the ZW sectional view, the height data 46 corresponding to the lead 45 has a larger value than those of the other leads. By this data comparison, a three-dimensional shape inspection such as a lead floating inspection of a lead becomes possible.

Further, since two-dimensional image data of the component 2 is input to the image memory 35, if this information is subjected to image processing, there is a difference between luminance data and height data.
The components can be positioned in the same manner as when performing image processing using an imaging device such as a camera.

FIG. 3 shows the mounting operation. In FIG. 3A, the trajectory represented by each arrow from point A to point B, point B to point C, and point C to point D indicates that the electronic component mounting apparatus of the present embodiment From the 3D sensor 8, and the 3D sensor 8
This represents a series of operations of capturing a two-dimensional image, performing image processing on the image data, performing component positioning / inspection, performing correction calculation of a mounting position, and mounting the component 2 at a required position on the printed circuit board 9. ing.

FIGS. 3B and 3C show changes in acceleration and deceleration of the movement of the robot in the x-axis direction and the y-axis direction corresponding to the locus of the part 2 shown in FIG. It shows the state of. Here, the part 2 passes over the 3D sensor 8 during the movement in the x-axis direction between the point B and the point C,
Here, a three-dimensional image is captured. During this time, the operation speed of the x-axis robot is constant, and the y-axis robot is stopped.

As for the remaining operations, in order to minimize the total mounting time, the operation between the points A and B is changed to the operation between the points B and C, and the operation between the points B and C is changed to the point. Acceleration / deceleration operations that involve a temporary stop at the speed switching point, which is an operation between C and D, are eliminated, and the speed of the machine mounting operation is increased.

The configuration and operation of the 3D sensor 8 will be described in detail below. FIG. 4 is a view of the 3D sensor 8 viewed in the x-axis direction, and FIG. 5 is a view of the 3D sensor 8 viewed in the y-axis direction. 4 and 5, reference numeral 10 denotes a semiconductor laser that emits laser light, 11 denotes a condensing / shaping lens that condenses / shapes the laser light, and 12 denotes a polygon mirror that scans the laser light hitting a mirror surface by mechanical rotation. , 13 are half mirrors that allow a part of the laser light to pass and partially reflect the laser light, and 14 is a mirror that reflects the light.

Reference numeral 15 denotes an F-.theta. Lens for converting the optical path of the laser light mechanically shaken by the polygon mirror 12 so that the laser light is projected perpendicularly onto the component 2 as an object.
Is an imaging lens that forms an image of the reflection (scattered light) of the laser light hitting the component 2, and 17a and 17b are position detections where the reflected light of the laser light that hits the component 2 is imaged through the imaging lenses 16a and 16b. It is a semiconductor position detecting element (hereinafter abbreviated as PSD) as an element, and has a function of generating an electric signal correlated with the position of an imaged light. 18
a and 18b are output signals of the PSDs 17a and 17b.

Here, the laser light emitted by the semiconductor laser 10 is condensed and shaped by the condensing lens 11, passes through the half mirror 13, and passes through the mirror 14.
And strikes the polygon mirror 12. The polygon mirror 12 is rotating at a constant speed, and the laser light hitting the mirror surface is swung. Further, the laser light whose optical path has been converted by the F-θ lens 15 is applied to the component 2 vertically, and the reflected light is imaged on the PSDs 17a and 17b via the imaging lenses 16a and 16b to form an image.
7b generates output signals 18a and 18b which can measure the height of the laser reflecting surface of the component 2.

In FIG. 5, reference numeral 19 denotes an optical sensor for detecting that light has been input, and reference numeral 20 denotes a signal for notifying that light has been input to the optical sensor 19 to the outside. It changes when the surface comes to a predetermined angle, which is equivalent to the origin signal (surface origin) of each surface of the polygon mirror 12. Further, for example, in the case of an 18-sided polygon mirror 12, a signal 18 times in one rotation is
It is output when each is rotated by an angle of equal intervals (every 20 degrees for 18 planes). This is called a rotation amount signal of the polygon mirror 12.

The 3D sensor 8 in this embodiment is
It has two systems of PSD circuits, but the main reason for this is that in one system, when laser light hits components, reflected light may not return to the PSD angularly in some cases. Provided for the purpose. In some cases, it is more effective to provide three or more systems, but technically, it is the same.
It will be explained in the system.

Here, the semiconductor position detecting element (PS)
D) An example of the method of measuring the height above the component 2 which is the measurement target by 17a and 17b is described below using the semiconductor position detecting element 17a.
The case (1) will be described with reference to FIG.

In FIG. 11, a laser beam that is scanned from the F-θ lens 15 in the direction perpendicular to the paper and projected onto the component 2 is irregularly reflected from the component 2. In this case, the point projected is assumed to be a and B ₁ point height H A ₁ point height 0 on the bottom surface of the component 2 from the bottom surface.

The irregularly reflected laser beam is applied to the imaging lens 16.
a, and each is collected by the semiconductor position detecting element 1
An image is formed at points A ₂ and B ₂ above 7a. As a result, A ₂
Electromotive force is generated at the point and the point B _2, and the currents I ₁ and I ₂ are extracted from the point C, and the currents I ₃ and I ₄ are extracted from the point D.

The currents I ₁ and I ₃ are determined by resistance components proportional to the distance x _A between the points A ₂ and C and the distance between the points A ₂ and D, and the currents I ₂ and I ₄ Is determined by a resistance component proportional to the distance x _B between the points B ₂ and C and the distance between the points B ₂ and D. Therefore, if the length of the semiconductor position detecting element 17a is L, x _a in FIG. 11, x _B is determined as follows.

X _A = LI ₃ / (I ₁ + I ₃ ) x _B = LI ₄ / (I ₂ + I ₄ ) Therefore, A on the semiconductor position detecting element 17a of FIG.
The distance between the _two points and the B ₂ points H 'is determined by the following equation.

H ′ = x _A −x _B The height H is determined based on the height H ′ above the PSD thus obtained.

Next, the mechanism for capturing a 3D image is shown in FIG.
This will be described with reference to FIG. In FIG. 6, reference numeral 21 denotes a main control unit of the electronic component mounting apparatus;
A reference position sensor 23 for notifying the main control unit 21 of a reference position for capturing the D image, a reference position signal 23 for notifying the main control unit 21 when the head unit 7 has passed this reference position sensor 22, Is an encoder of a motor for moving the x-axis robot 5, and 25 is an encoder 24
Is the encoder signal that is output.

When the component 2 picked up from the tray 3 moves on the x-axis by the x-axis robot 5, the encoder 24 always outputs an encoder signal (AB phase, Z phase or a signal equivalent thereto) 25 to the main control unit. Since the reference position signal 23 is given to the main control unit 21 when the component 2 passes through the reference position sensor 22,
The main control unit 21 can calculate the relative position of the component 2 from the reference position on the x-axis based on these two signals.

On the other hand, the rotation amount of the polygon mirror 12 in the 3D sensor 8 is always given to the main control unit 21 as the rotation amount signal 20 while the polygon mirror 12 is rotating. The amount of rotation of the mirror 12 after passing through the reference position can be calculated.

Here, the amount of rotation of the polygon mirror 12 increases in proportion to its speed, and the same applies to the amount of movement of the x-axis robot 5. On the other hand, the 3D sensor 8 in the present embodiment is based on the premise that the polygon mirror 12 and the x-axis robot 5 at the time of capturing a 3D image rotate and go straight at a constant speed. If this condition is disturbed, the resolution (pixel size) per pixel in the horizontal and vertical directions of the captured 3D image will vary according to the speed unevenness. This is an error factor in measurement accuracy. Therefore, in the electronic component mounting apparatus according to the present embodiment, the 3D sensor 8 having the above-described configuration captures a 3D image into the image memory 35 in the main control unit 21, and the polygon mirror 12 that basically rotates at a constant speed. In order to monitor and control the consistency of the operation between the head units 7 driven by a motor such as a servomotor, the rotation amount signal 20 of the polygon mirror 12 and the encoder signal 25 of the motor are used.

In FIG. 7, reference numeral 26 denotes an encoder signal 2
5, a movement amount detection circuit for calculating the movement amount (distance) of the x-axis robot 5 from the reference position, and a movement speed 27 for receiving the encoder signal 25 and calculating the movement speed of the x-axis robot 5 at each time. The detection circuit 28 is a polygon mirror 12
The rotation amount detection circuit 29 receives the rotation amount signal 20 and calculates the rotation amount of the x-axis robot 5 from the reference position, and receives the rotation amount signal 20 and calculates the rotation speed of the polygon mirror 12 at each time. A speed detection circuit for comparing a movement amount between the operation of the x-axis robot and the rotation of the polygon mirror;
A comparison circuit 31 for comparing the movement speed between the operation of the x-axis robot and the rotation of the polygon mirror;
Reference numerals 2 and 33 denote storage circuits for storing the comparison results of the comparison circuits 30 and 31, respectively; 34, a processor circuit for controlling and monitoring the entire main control unit 21; and 35, a 3D image (height image) which is fetched and stored. An image memory 36 stores a timing generation circuit for generating various timing signals for capturing the PSD outputs 18a and 18b sent from the 3D sensor 8 into the image memory 35, and 37 designates a PSD output 1
An interface circuit for the main control unit 21 to receive 8a and 18b, and a height calculation circuit 38 for converting and correcting the PSD outputs 18a and 18b to a height signal.

The PSD output 18 generated by the 3D sensor 8
a and 18 b are input to the main controller 21 by the interface circuit 37. The input PSD output 18a,
Basic signals 18b are the original signals output from the PSDs 17a and 17b. In order to perform software processing on the height image, various operations such as height conversion and correction operations are performed on the PSD outputs 18a and 18b. And the height calculation circuit 38 does this. The signal calculated by the height calculation circuit 38 is taken into the image memory 35 as height data, and subjected to various software processes by the processor circuit 34.

The height data is taken into the image memory 35 sequentially for each horizontal line in the image memory 35. The rotation amount signal 20 of the polygon mirror 12 is used as a synchronization signal (reference signal) for each polygon surface. It is used.

In such a series of imaging operations, the operation of the x-axis robot 5 (that is, the movement of the part to be imaged) and the operation of the polygon mirror 12 are performed independently, and the operation of the x-axis robot 5 is performed based on the encoder signal 25. The movement amount / speed is calculated by the movement amount detection circuit 26 and the movement speed detection circuit 27, respectively, and the rotation amount / speed of the polygon mirror 12 is calculated based on the rotation amount signal 20 of the polygon mirror 12.
8 and the rotation speed detection circuit 29, respectively, and compares the movement amount and the movement speed of the x-axis robot 5 and the polygon mirror 12 with the comparison circuits 30 and 31, and stores the comparison result in the storage circuits 32 and 33. This monitors or controls the synchronous operation of both the movement of the x-axis robot 5 and the rotation of the polygon mirror 12.

As an example of monitoring, the comparison circuit 30,
In each of the comparing circuits 31, if the difference is within the allowable range as a result of the comparison, the data recorded in the image memory is treated as valid data, while if the difference is outside the allowable range, the data is invalidated. If the comparison error is larger than a certain value, it is determined that the image is defective, and the image is retaken, or the 3D image in the image memory 35 is provided with software or an additional circuit to perform normalization and correction processing by referring to the comparison result. Conceivable.

Here, an example of converting the rotation amount of the polygon mirror 12 into the movement amount will be described. Now, suppose that the polygon mirror 12 is a dodecahedron and the polygon mirror 12 is 30 °.
(= 360 ° ÷ 12) While rotating, part 2
It is assumed that it is designed to move by 0 μm. At this time, assuming that the rotation amount of the polygon mirror 12 after the start of image capturing is 125.5 rotations, the component 2 has 125.5 (rotation) × 12 (plane / rotation) × 40 (μm) = 60240
(Μm).

In order to realize this in a circuit, the number of pulses of the rotation amount signal 20 from the polygon mirror 12 (the number of signals from the plane origin which is the reference point of each plane of the polygon mirror 12)
May be counted during image capture. In the above example, 125.5 (rotation) when 125.5 rotation is performed
× 12 (number of plane origins) = 1506, the plane origin is counted.

Therefore, the number of pulses of the rotation amount signal 20 is 15
When the number reaches 06, it can be considered that the component 2 has moved by 40 μm, and the rotation amount of the polygon mirror 12 can be converted into the movement amount.

FIG. 8 is a diagram showing the internal configuration of the height calculating circuit 38. Reference numeral 41 denotes an A / D conversion circuit for A / D converting the PSD outputs 18a and 18b; 42, a clock generation circuit;
Is a clock selection circuit as a clock speed changing means for selecting one from a plurality of clocks generated from a clock generation circuit 42 and providing a clock of one speed (frequency) to the A / D conversion circuit 41 and the image memory 35. , 44 is PS
A height conversion circuit 45 that calculates the D outputs 18a and 18b based on the principle of triangulation, and corrects a non-linear relationship between the position of light that forms an image on the surface of the PSDs 17a and 17b and the position of laser light that strikes a measurement target. This is a height correction circuit. In this case, two or more kinds of clocks generated by the clock generation circuit 42 are selected by the clock selection circuit 43, and this signal is required in the main control unit 21. The selected circuit is supplied to a required circuit such as the A / D conversion circuit 41 and the image memory 35, and at the same time, the operating speed of the x-axis robot is accelerated / decelerated in inverse proportion to the speed of the clock, thereby providing a special circuit. It is possible to change the resolution while keeping the horizontal and vertical pixel sizes of the captured image (3D image) equal without adding.

For example, it is assumed that the A / D conversion is performed at 4 MHz and the pixel size in the horizontal and vertical directions is equal to 50 μm when the x-axis robot 5 is moved at 100 mm / s. At this time, an 8 MHz clock is selected and given to each required circuit, and if the x-axis robot is moved at 50 mm / s, the pixel size (resolution) of the captured image is obtained.
Can be 25 μm pixels.

At this time, the data amount per row (horizontal row) is doubled, and the same can be said for the vertical direction. Therefore, in order to obtain an image with double resolution for the same visual field size, the capacity of the image memory 35 is quadrupled. For this, the image memory 35
It is a choice of whether to select a larger capacity or to limit the field of view when improving the resolution.

Next, the relationship between each signal in the image processing operation from the image capture by the main control unit 21 will be described with reference to FIG.
And FIG. 8, FIG. 12, and FIG. The motor is built in the x-axis robot 5 that moves the head unit 7 that adsorbs the component 2, and an AB-phase signal indicating a normal movement distance and a fixed position ( And a Z-phase signal representing a certain rotation angle of the motor).

The Z-phase signal and a position detection sensor for detecting a reference position (a photo sensor,
When both the position detection sensor signal and the position detection sensor signal are received, the image data capturing operation is started.

The time from when both the Z-phase signal and the position detection sensor signal are received until the start of image data capture is very short.
As shown in FIG. 13, in synchronization with a rotation amount signal indicating the surface origin of the polygon mirror 12, a series of operations of laser emission and image data capture are automatically performed by hardware without a processor circuit. , The timing generation circuit outputs image data fetch timing.

With this output, for example, image data for 1000 lines is fetched. In this way, the point in time when the rotation amount signal 20 is captured is treated as a reference position (surface origin) of each surface of the polygon mirror 12 and is used as a reference for starting image data capture. And, for example, 1000 per part
In the case where the image data of a row is taken in, when the image data of 1000 rows is taken in, the image taking in for the part concerned is automatically terminated.

As described above, two analog signals are input from the PSD outputs 18a and 18b, and are amplified by the amplifier circuit 202 as shown in FIG.
The two analog signals are A / D converted by the A / D conversion circuit 41 of the height calculation circuit 38 via the interface circuit 37. Thereafter, the above-described height calculation is performed based on each of the two digitized signals of the PSD outputs 18a and 18b to calculate the height position of the lead. Here, if the value of the digitized signal is within the allowable range, the subsequent processing is performed as normal data. If the value is out of the allowable range, the subsequent processing is stopped as abnormal data. That is, two P
In the SD outputs 18a and 18b, if the value of one of the outputs is within the allowable range, only the PSD output within the allowable range is used, and if the values of both outputs are within the allowable range, the average value of both is taken. If both output values are out of tolerance, both P
The subsequent processing for the SD output is not performed, and processing is performed assuming that an error has occurred.

After calculating the lead height data in this way, the height correction circuit 45 performs height correction. This height correction is performed because the position on the PSDs 17a and 17b does not change linearly even if the position of the incident light with respect to the PSDs 17a and 17b changes linearly. The calculated height data is stored and corrected to obtain accurate height data.

The height data corrected in height is input to the image memory circuit 35, and the timing obtained from the timing generation circuit 36 is stored as an address. And
It is determined from the data stored in the storage circuit 32 as a result of the comparison between the rotation amount detection circuit 28 and the movement amount detection circuit 26 by the comparison circuit 30 whether or not the image data is within the allowable range. If not, the image data stored in the image memory circuit 35 is treated as invalid. If it is within the allowable range, the processor circuit 34 sends the image memory circuit 3
5 is read out, and image processing such as positioning of components is performed.

An example of the flow of the image capturing operation for the one component 2 and the processing operation of the captured image will be described in more detail with reference to FIG. First,
In step # 60, the image of the component 2 is captured.

Next, in step # 61, the positioning of the lead of the component 2 from which the image has been captured is performed. There are various methods (algorithms) for this positioning, but a representative one will be described here.

First, as shown in FIG.
For example, the inclination of the lead on one side of the rectangular electronic component 2 is roughly detected. Next, as shown in FIG. 15B, the positions of two leads arbitrarily selected from the detected leads are roughly detected.

Finally, as shown in FIG. 15C, the lead position is accurately detected based on the roughly detected lead position. When the position of the lead on one side of a quadrangular component such as QFP is detected in this way, the lead on the other side is determined based on this lead position as shown in FIG.
The lead position may be detected with high accuracy as shown in FIG.

Next, it is determined at # 62 whether or not the lead pitch is appropriate. If it is appropriate, the height of each lead is calculated in step # 63 as described above. The calculation of this height is
As shown in FIG. 17, from the lead position information obtained in step # 61, the leading end 204 of each lead is obtained.
By averaging the height information (this is the data itself stored in the image memory) of a plurality of pixels (corresponding to small squares in FIG. 17) around (hatched portions in the figure), the read is performed. Height is required. Information (x _i , y _i , z _i ) obtained by adding the height of each lead to the position of each lead obtained by positioning is the three-dimensional position of each lead. Here, i = 1,..., N, and n is the number of leads.
Next, a virtual plane (seating plane) is calculated in step # 64. Here, the virtual plane will be described.

In general, when a component having a plurality of leads such as a QFP is mounted on a board, a part of the leads may be separated from the electrode portion of the board, that is, a so-called lead floating state may occur. The process for detecting the floating of the lead of the component before mounting the component is the detection of the floating of the lead performed in step # 65. If this process is to be performed in a state where the component is sucked by the nozzle, FIG. Since there is a possibility that the component 2 is inclined and adsorbed to the nozzle 7a as shown in (2), it is not possible to accurately determine the height of each lead simply by determining the height of each point of the lead. Therefore, it is necessary to obtain a virtual plane that becomes a ground plane when components are mounted, obtain a distance from the virtual plane to each lead, and evaluate the floating amount of the lead.

In FIG. 16A, reference numeral 201 denotes a reference plane, and reference numeral 200 denotes an error (H ₁ −H ₂ ) between the heights of the two leads due to an inclination generated in the component 2 due to the suction of the nozzle 7a.
Is shown.

The virtual plane 202 is a plane composed of three lead positions of the component 2, and a plane satisfying the following two conditions can be a constituent point of the virtual plane 202. (1) As shown in FIG. 16B, all lead positions are located above or on the virtual plane 202.

(2) As shown in FIG. 16C, a point where the center of gravity of the part 2 is projected on the virtual plane 202 (center of gravity projected point)
203 exists in the triangle generated by the three points of the lead positions constituting the virtual plane 202.

Next, based on the height calculated in step # 63 and the virtual plane obtained in step # 64, it is determined in step # 65 whether the float of the lead is within an allowable range. The lifting of the leads is performed by calculating the distance from the three-dimensional position of the leads to the virtual plane determined for all the leads. This distance is the amount of lead lift of each lead from the virtual plane, and if this value is within the allowable range, the image processing operation ends. If it is out of the allowable range, the image processing operation is terminated in step # 67 as a lead floating error. If the lead pitch is outside the allowable range in step # 62, the image processing operation is terminated as a pitch error in step # 66.

Next, an example of a process for correcting a shift in image capture timing will be described. FIG. 12 is a diagram showing the relationship between the main control unit 21 of FIG.
6 to 29, comparison circuits 30 and 31, storage circuits 32 and 33,
The processor circuit 34 is shown as one polygon mirror control unit 200. FIG. 13 is a timing chart showing the image capture timing.

In FIGS. 12 and 13, when the component 2 is located at a specific position in accordance with the movement of the head 7, the three-dimensional sensor 8 outputs the position detection sensor signal, and the encoder output 1 of the motor for moving the component. The polygon mirror controller 200 enters a preparatory operation for taking in image data at the timing when the Z phase comes out.

After the preparation operation is started, actual image data is taken in line by line in synchronization with the operation of detecting the plane origin of the polygon mirror 12. That is, when the rotation amount signal 20 indicating the plane origin of the polygon mirror 12 is detected and the laser light of the semiconductor laser 10 is emitted, the image is taken in at the same time.

At this time, as shown in FIG. 13, there is a time lag from when the head section 7 is positioned at the image data fetching start position to when the image data fetching operation is actually started. This time lag is caused by the head 7 and the polygon mirror 1
2 is asynchronous, the amount of movement t of the component 2 by the time the image is captured, and the delay of a fixed time “preparation period” due to circuit setup. .

After the time lag, one frame's worth of image is captured in synchronization with the polygon mirror 12. Therefore,
By moving the component by the distance that the component 2 moves in the time from when the component 2 is located at the image capturing start position of the three-dimensional sensor 8 to when the polygon mirror 12 of the three-dimensional sensor 8 is located at the scanning start position. The encoder output (AB phase) of the motor is counted and obtained in a circuit by a counting circuit 300,
Output to the processing circuit 34. If the positioning of the component 2 is performed based on the result, it is possible to prevent a decrease in the positioning accuracy due to a variation in the timing shift, and to perform the positioning with higher accuracy.

In the above embodiment, the case where the head 7 sucks one electronic component 2 with one suction nozzle has been described. However, the present invention is also applicable to the case where the head 7 has a plurality of nozzles. Applicable. Further, when positioning and component shape inspection are continuously performed in such a state that a plurality of components are sucked by a plurality of nozzles, for example, when it is assumed that 1000 rows of image data are taken in for each component, 4
Each nozzle takes in 4000 rows of image data,
It is handled as image data of one component for every 1000 lines.

The time required for component positioning and three-dimensional shape inspection in the tact time is extremely long. However, according to the present invention, when a plurality of components are successively captured with a 3D sensor by a plurality of nozzles and a three-dimensional image is successively mounted, the time required for component movement from the removal of the component to the mounting target board is one. Regardless of whether it is a single part of a nozzle or a multiple part of a plurality of nozzles, it is substantially constant, and the effect is particularly great in terms of shortening the tact time.

In the head unit 7 having a plurality of nozzles as described above, the image processing order can be appropriately changed in consideration of the mounting order of the electronic components 2 as shown in FIG. That is, for example, four nozzles (No. 1 to N
o. No. 4) picks up the component 2 in this order and loads the image data into the image memory circuit 35, while No. 4 picks up the image data. 4-No. When four nozzles are mounted on the board in the order of 1, every time image data of each component is captured, image processing of the captured image data is prioritized over image processing of image data of other components. It is also possible to judge whether or not to perform the process, and to prioritize the image processing of the component to be given the highest priority.

In such a case, since the image processing is performed in order from the earliest mounting, if the image processing is completed,
Mounting can be performed even during image processing of another component. Further, as is clear from the above description, in order to increase the resolution, it is necessary to reduce the speed of the x-axis robot 5 at the same time as improving the clock speed.

In any case, in order to cope with the narrow pitch of components such as QFPs and connectors, it is indispensable to increase the resolution of an image. You want to take an image. In such a case, the means for increasing the resolution is very effective.

In the above-described embodiment, the output of the encoder 24 is used to detect the relative position of the head unit 7 from the reference position on the x-axis robot 5.
By applying a linear scale directly to the axis robot 5, the position of the head unit 7 can also be detected.

[0093]

As described above, according to the present invention, a height image is captured by using the three-dimensional image capturing means, and image processing is performed on the three-dimensional image captured by the three-dimensional image capturing means. In one step, positioning of an electronic component to be mounted and three-dimensional component shape inspection typified by lead floating inspection can be performed simultaneously.

Therefore, it is possible to reduce a mounting tact time when mounting a component that requires a three-dimensional shape inspection such as a lead floating inspection. In addition, the operation speed of a head unit moving device (for example, an x-axis or y-axis robot) for moving the head unit is kept constant, and during the mounting operation before and after this, the movement of the components is not stopped, and the two-axis basically asynchronous. (For example, a driving axis and a polygon motor axis along the moving direction of the moving device) are mechanically operated to capture a three-dimensional image by the three-dimensional image capturing means, so that the pixel size (resolution) in both the horizontal and vertical directions is reduced. The system can be guaranteed.

Therefore, it is possible to guarantee the pixel size (resolution) in both the horizontal and vertical directions with respect to the captured image at the time of component mounting. Also, when mounting a narrow pitch component such as a QFP or a connector, a high-resolution image is captured in a captured image of the mounted component, while when mounting a component that can be measured with a somewhat coarse resolution, the mounting is performed. In the captured image of the component, the resolution can be reduced while maintaining the normality of the pixel (compared to the case where the resolution is increased), and the image can be captured by fast scanning.

Therefore, when mounting a narrow-pitch component such as a QFP or a connector, it is possible to flexibly cope with an increase in the speed and resolution (high accuracy) of the mounting.

[Brief description of the drawings]

FIG. 1 is an overall schematic diagram of an electronic component mounting apparatus according to an embodiment of the present invention.

FIG. 2 is an explanatory view of capturing a three-dimensional image in the embodiment.

FIG. 3 is an explanatory diagram of a component mounting operation in the embodiment.

FIG. 4 is a cross-sectional view of the configuration of the 3D sensor according to the embodiment in the x-axis direction.

FIG. 5 is a sectional view of the configuration of the 3D sensor according to the embodiment in the y-axis direction.

FIG. 6 is an explanatory diagram of an output signal from a 3D sensor according to the embodiment.

FIG. 7 is an internal configuration diagram of a main control unit in the embodiment.

FIG. 8 is an internal configuration diagram of a height calculation circuit according to the embodiment;

FIG. 9 is a mounting process diagram in a conventional electronic component mounting apparatus.

FIG. 10 is a mounting process diagram in the electronic component mounting apparatus according to the embodiment of the present invention.

FIG. 11 is an explanatory view showing an example of a height measuring method in the embodiment.

FIG. 12 is an explanatory diagram showing a relationship between a main control unit and each device in the embodiment.

FIG. 13 is a timing chart showing image capture timing in the embodiment.

FIG. 14 is a flowchart showing an operation from image capture to image processing in the embodiment.

FIG. 15 is an explanatory diagram showing an algorithm as an example regarding recognition of leads of an electronic component.

FIG. 16 is an explanatory diagram relating to measurement of the height of floating of a lead of an electronic component.

FIG. 17 is an explanatory diagram of calculating the height of each lead of an electronic component.

FIG. 18 is a timing chart of an embodiment in a case where image capturing and image processing of a plurality of electronic components are performed.

[Explanation of symbols]

 Reference Signs List 4 tray supply unit 5 x-axis robot 6a, 6b y-axis robot 7 head unit 8 three-dimensional sensor 10 semiconductor laser 12 polygon mirror 17a, 17b semiconductor position detecting element (PSD) 16a, 16b imaging lens 21 main control unit 26 moving amount Detection circuit 27 Moving speed detection circuit 28 Rotation amount detection circuit 29 Rotation speed detection circuit 30 First comparison circuit 31 Second comparison circuit 35 Image memory 43 Clock selection circuit

Claims (7)

[Claims] A component supply unit that supplies an electronic component to be mounted on a substrate; a head unit that holds the electronic component; a head unit moving device that moves the head unit; And a three-dimensional image capturing unit that obtains height data for each line by performing line scanning with a laser beam, and an image that stores the height data from the three-dimensional image capturing unit as three-dimensional image data An electronic component mounting apparatus, comprising: a memory; and a control unit that performs image processing on the three-dimensional image data of the electronic component. 2. The control unit according to claim 1, wherein a three-dimensional image obtained by laser beam scanning in a direction perpendicular to a moving direction of the electronic component is taken into an image memory, and an operation speed of a head unit moving device for moving the electronic component is kept constant. The electronic component mounting apparatus according to claim 1, wherein: 3. An electronic component moving device for moving an electronic component to be mounted on a substrate, a polygon mirror disposed below the moving device, and a semiconductor laser that emits laser light to the polygon mirror. And one or more position detecting elements disposed around the polygon mirror; and an imaging lens for forming an image of the laser light impinging on the bottom surface of the electronic component on the position detecting element; The laser is arranged so that the laser light is reflected by the rotating polygon mirror while rotating, and hits the bottom surface of the electronic component passing on the polygon mirror, and the moving device passes the electronic component on the polygon mirror. The data output by the position detecting element is calculated based on the laser scanning generated by the rotational movement of the polygon mirror. The captures 3-dimensional image of the electronic component in the image memory obtained Te, an electronic component mounting apparatus and performs positioning and the part shape inspection of the electronic component in the three-dimensional image. A moving amount detecting circuit for calculating a moving amount of the electronic component moving device from a reference position; A first comparison circuit that compares the amount of movement of the electronic component moving device with the amount of rotation of the polygon mirror. If the difference between the two is within an allowable range, 4. The electronic component mounting apparatus according to claim 3, wherein the data recorded in the image memory is treated as valid data, and the data is invalid if the data is outside the allowable range. 5. A moving speed detecting circuit for calculating a moving speed of an electronic component moving device at each time, and a rotating speed detecting device for receiving a rotation amount signal of a polygon mirror and calculating a rotating speed of the polygon mirror at each time. A second comparison circuit that compares a moving speed of the electronic component moving device with a rotation speed of the polygon mirror. If a difference between the two is within an allowable range as a result of the comparison by the second comparing circuit, 5. The electronic component mounting apparatus according to claim 3, wherein the data recorded in the image memory is treated as valid data, and the data is invalid if the data is outside the allowable range. 6. A clock speed changing means for changing a speed of a basic clock for taking in a three-dimensional image, wherein when a high resolution is required for the three-dimensional image, the clock speed changing means changes the basic clock. And moving the electronic component moving device at a low speed,
If high speed is required to capture the three-dimensional image,
6. The electronic component mounting apparatus according to claim 3, wherein the clock speed changing unit lowers the basic clock and increases the moving speed of the electronic component moving device. 7. A calculating means for calculating a moving distance of the electronic component during a time from when the electronic component is positioned at the image capturing start position to when it is positioned at the scanning start position by laser light, The electronic component mounting apparatus according to any one of claims 3 to 6, wherein the electronic component is positioned in a three-dimensional image in consideration of the distance calculated by: