JPH04196336A - Floating detector of flat plate type electronic part lead - Google Patents

Abstract

PURPOSE:To enable the floating of leads to be detected with high precision by a method wherein a laser displacement gauge is scanned oppositely to the multiple leads of a flat plate type electrode part. CONSTITUTION:A flat plate type electronic part 10 protruding multiple leads 11 is held by a suction nozzle 2 while a laser displacement gauge 12 is arranged free-oppositely to the multiple leads 11 so that the laser displacement gauge 12 may scan in the passing direction across the multiple leads 11 by the relative movements of the suction nozzle 2 and the laser displacement gauge 12. Through these procedures, the laser displacement gauge 12 can oppositely scan the multiple leads 11 of the flat plate type electronic part 10 so that the gaps between respective leads 11 and the laser displacement gauge 12 i.e., the floating of the leads 11 may be detected with high precision.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is applicable to QFP type IC, SOP type IC, PLCC type I
The present invention relates to a floating detection device for flat electronic component leads suitable for detecting floating of leads of flat electronic components (such as surface-mounted ICs) having a large number of leads such as C and LCC type ICs.

(Summary of the Invention) The present invention provides floating detection of flat electronic component leads for detecting floating of the leads of a flat electronic component (surface-mounted IC, etc.) in which a plurality of leads are protruded along the sides. In the device, a flat electronic component is held by a suction nozzle, a laser displacement meter is fixed to an X-Y table, and relative movement between the suction nozzle and the X-Y table moves the laser displacement meter to the plurality of leads. By scanning in the transverse direction, lead lifting can be detected with high precision and high speed.

(Prior technology) Flat electronic components such as surface-mount ICs have many leads pulled out at minute intervals, and if the leads are bent, misaligned, or lifted, it may cause problems when mounted on a printed circuit board (soldering). connection failures are likely to occur with respect to the pattern on the printed circuit board. It is possible to detect bent or misaligned leads by directly photographing the leads of a flat electronic component with the TV left camera. This is difficult to achieve with a camera-based configuration. Here, lead floating means that when a flat electronic component 10 such as a surface-mounted IC is placed on a printed circuit board l as shown in FIG. This causes the lead IIB to float above the board surface, causing a soldering failure.

Conventionally, a device for detecting lead floating as described above has been proposed by the present applicant in Japanese Patent Laid-Open No. 63-262852. In this device, a flat electronic component is placed on a fiber plate and light is irradiated from an oblique direction. TV
This method focuses on the fact that the left camera image changes.

(Problems to be Solved by the Invention) By the way, it is recognized that the configuration of JP-A No. 63-262852 has a drawback in the measurement accuracy of REET floating.

That is, if the lead lift is large, a discernible change will occur in the TV camera image below the fiber plate, but if the lead lift is slight, it may not be detectable. In particular, when considering the recent narrowing of lead widths and lead arrangement pitches and the miniaturization of patterns on printed circuit boards, even the presence of slight floating leads may cause soldering defects.

SUMMARY OF THE INVENTION In view of the above-mentioned points, it is an object of the present invention to provide a floating detection device for a flat electronic component lead that can quickly and accurately detect floating leads of a flat electronic component.

(Means for Solving the Problems) In order to achieve the above object, the present invention holds a flat electronic component having a plurality of leads protruding along its sides with a suction nozzle, and A laser displacement meter is arranged so as to freely face the suction nozzle, and the laser displacement meter is configured to scan in a direction across the plurality of leads by relative movement between the suction nozzle and the laser displacement meter.

(Function) In the flat electronic component lead floating detection device of the present invention, the distance between each lead and the laser displacement meter is determined by scanning a plurality of leads of the flat electronic component with the laser displacement meter facing each other. In other words, lead floating can be detected with high accuracy. The measurement accuracy is determined by the performance of the laser displacement meter itself, but a resolution of about 20 μm can be obtained. In addition, flat electronic components can be held using a suction nozzle for mounting flat electronic components on a printed circuit board, and scanning with a laser displacement meter can be performed using an X-Y table on which the printed circuit board is mounted. Since it can be implemented, it can be realized with a simple and inexpensive mechanism.

Furthermore, the configuration is configured to amplify the output of the laser displacement meter, sequentially store the measured value at the widthwise center of each lead with the most stable height in a memory, and detect lead floating by mutually comparing the stored contents of the memory. If so, it is possible to quickly detect floating leads even in a flat electronic component having a large number of leads.

(Example) Hereinafter, an example of the floating detection device for a flat electronic component lead according to the present invention will be described with reference to the drawings.

FIG. 1 shows the overall configuration of the embodiment. 1 is an X-Y table for positioning and holding a printed circuit board, 2 is a suction nozzle for sucking and holding electronic components, and 3 is the current position of the X-Y table. 4 is an AC servo motor for driving the X-Y table, 5 is a servo drive for driving the X-Y table, and 6 is an NC controller, which are used to mount electronic components on a printed circuit board. It is also the main component of the machine. The encoder, servo motor, and servo drive are respectively provided for the X-axis and Y-axis of the X-Y table.

A laser displacement meter 1 is mounted on the X-Y table 1 so as to be able to freely face each lead 11 protruding along each side of the flat electronic component 10 such as a QFP that is suction-held by the suction nozzle 2.
2 is fixed. The output of this laser displacement meter 12 is amplified by a displacement meter controller 13 and input to an analog sample controller 14 . The analog sample controller 14 includes a laser displacement meter 12 and each lead 11.
The distance from the center in the width direction of the lead (that is, the measured value including lead float information) is converted into a digital value and stored, and when the detection data for all the leads is collected, the detection data is sent to the computer in the NC controller 6. is transmitted via the VME bus. The laser displacement meter 12
The details of the configuration and operation of the analog sample controller 14 will be described later.

FIG. 2 shows an example of the basic configuration of the laser displacement meter 12.
Laser light source 20 for generating infrared laser light, etc.
, the projection lens 21, the condensing lens 22, and the one-dimensional P
S D 23 (Po5ition Sensitive
Light Detector: Semiconductor level 1 detection element). This one-dimensional PSD 2B is an element that can detect the position of the focused spot because the inter-electrode resistance changes depending on the position of the focused spot.

In the configuration shown in FIG. 2, the distance from the center of the projection lens 21 to the object is detected using the principle of triangulation. That is, the range of distance β to be measured is from Jl1mw+ to I!
ztt+wn, the distance between the optical axes of the light projecting lens 21 and the condensing lens 22 is Bmm, and the distance between the condensing lens 22 and the PSD light receiving surface is fmm, then the distance is 1+.

PSD light receiving surface (full length) at I2) x
,,x2 is Xl: B-f! .

X2=B f I2, and it can be seen that the focused spot moves according to the distance, and as the focused spot moves, the resistance between the electrodes of the one-dimensional PSD 23 changes, and the current 1. , I2 changes. Therefore,
Distance from the currents II and I2 to the object, that is, the lead 11 of the flat electronic component 10 that is hit by the laser beam (distance from the projection lens 21 to the lead 11: approximately 30 mm)
It turns out that it is possible to detect.

The displacement meter controller 13 is the one-dimensional PSD 23 described above.
The current change is amplified and a voltage signal of plus or minus several volts approximately proportional to the distance between the laser displacement meter 12 and the lead is output.

FIG. 3 shows details of the analog sample controller 14, which includes an A/D converter 30 that A/D converts the amplified output of the laser displacement meter, that is, the analog input from the displacement meter controller 13, and a flat electronic component. An X-axis force 9 protruding from each side of the lead 11 defines the sample position for the lead along the X-axis direction.
31, a Y-axis counter section 32 that defines the sample position for the leads with respect to the side along the Y-axis direction, a memory 33 that stores the distance measurement value after digital signal conversion for each lead, and a memory 33 that stores the total number of sampling data. A total number counter 34 for counting, a start address designation counter 35 for designating a memory write start address, and a data selector 36 for sequentially switching memory addresses.
, a data buffer 37, a status read latch 38, a control output write latch 39, and a busy F/F (flip-flop >40) that generates a busy output indicating that memory writing is in progress. a timing adjustment section 41 for adjusting the conversion timing of the /D converter 30; an encoder interface 42 for receiving and receiving signals about the X-axis and Y-axis of the rotary encoder 3 on the side of the X-Y table 1; N.C.
VME for connecting to the VME bus on the controller 6 side
It includes a bus interface 43, a decoder 44, various gates, and the like.

When scanning the laser displacement meter 12 in the X-axis direction by moving the X-Y table 1 in the X-axis direction, the A counter 31A for specifying a sample start position that counts the distance to the center in the width direction of the leads 11, a counter 31B for specifying a sample pitch indicating the distance 1fi L p between the centers in the width direction of adjacent leads, and a sample pitch in the X-axis direction. It also has a sampling number indicating counter 31C for indicating the number of samples. Similarly, the Y-axis force 9 Fu 2 part 32 is
When scanning the laser displacement meter 12 in the Y-axis direction by moving the table 1 in the Y-axis direction, the first lead 11 in the Y-axis direction is A counter 32A for specifying a sample start position for counting the distance to the center in the width direction, a counter 32B for specifying the sample pitch indicating the distance Lp between the centers in the width direction of adjacent leads, and a counter 32B for specifying the sample pitch for indicating the number of samples in the Y-axis direction. It has a counter 32C for indicating the number of samples.

Next, the operation of the embodiment will be explained according to the flowchart shown in FIG. First, in Step #1 "Pickup", the suction nozzle 2 picks up and holds the desired flat electronic component 10 from the electronic component supply section, and in Step #2 [Move to the imaging position], the suction nozzle 2 picks up the desired flat electronic component 10 from the electronic component supply section. Imaging means (move to the imaging position of the TV left camera. Step #3 "Image processing analysis")
Now, as shown in FIG. 5, the rotation (direction deviation amount) Δ in the horizontal plane of the flat electronic component 10 that is attracted by the suction nozzle 2 that is stationary.
θ, the amount of deviation ΔX, ΔY in the X-axis and Y-axis directions between the center of the suction nozzle and the center of the component, and the position of the first lead 11 (for example, the center of the lead tip) F(X, Y) are determined. Step #4
In "Correction rotation of θ", Δ
The suction nozzle 2 performs a correction rotation so as to offset θ and assume a correct posture. Step #5 "Determine the detection start and end positions" is performed from the position F (X, Y) of the first lead 11 of the flat electronic component 10 after correction rotation to the scanning start position of the laser displacement meter 12 as shown in FIG. (Lead floating detection start position) St (X, Y) is determined. This St is also the scan end value 1. Note that the calculations and control processing in steps #1 to #5 are executed on the NC controller 6 side.

The number of leads, lead width Lw, and lead pitch Lp for the sucked flat electronic component 10 are stored in the table on the NC controller 6 side. 14, parameters such as the first lead position fiF (X, Y), scanning direction, lead pitch Lp, and number of leads after Δθ correction in FIG.
Enter via bus. 1st lead position F (X, Y)
is preset in the sample start position designation counter 31A of the X-axis force 972 section 31, and similarly, 1 in the Y-axis direction
The th read position is preset in the sample start position designation counter 32A of the Y-axis force 9F2 section 32. X
The lead pitch Lp in the axial direction is preset in the sample pitch instruction counter 31B of the X-axis force 972 section 31, and the lead pitch Lp in the Y-axis direction is preset in the sample pitch instruction counter 32B of the Y-axis force 972 section 32. . The number of leads in the X-axis direction is preset in the counter 31C for indicating the number of samples of the X-axis force 972 section 31, and the number of leads in the Y-axis direction is preset in the counter 32C for indicating the number of samples of the Y-axis force 972 section 32, respectively. Further, the total number of leads is preset in the total number counter 34.

In step #7 "laser displacement meter movement data sampling", the suction bottle 2 side is fixed, and the laser displacement meter 12 is scanned from the scanning start point St in the X-axis direction, )'-axis direction, X-axis direction, Y-axis direction, as shown in FIG. Scanning is performed at a constant speed along the four sides of the flat electronic component 10 in the axial direction. The distance measurement signal after the laser displacement meter output is amplified by the displacement meter controller 13 (signal indicating the distance between the laser displacement meter and the door 11 hit by the laser beam of the laser displacement meter) is shown in FIG. It can be seen that the distance measurement signal when the laser beam of the laser displacement meter hits the center of the lead 11 in the width direction is stable and highly reliable. Therefore, when sampling the distance measurement signal from the displacement meter controller 13 using the analog sample controller 14, each lead 11
The distance measurement signal corresponding to the center in the width direction is A/D converted and written into the memory 33.

The operation of step #7 will be explained using FIG. 3.

The NC controller 6 outputs a signal to the X-Y table driving servo drive 5 to move the X-Y table 1 in the X-axis direction, and at the same time, the control output writing latch 38 in the analog sample controller 14 also starts operating. A signal is sent out. As a result, the operation of the laser displacement meter 10 is turned on, and the busy F/F 40 is turned on.
A busy output indicating that memory is being written is output. As a result, the X-axis count pulse indicating the movement of the X-Y table 1 in the X-axis direction is transmitted from the rotary encoder 3 on the X-Y table side to the counter 31A for specifying the sample start position in the X-axis counter section 31 and for indicating the sample pitch. It is added to the counter 31B as a clock (CLK).

The sample start position designation counter 31A detects that the X-Y table 1 has moved by the distance from the scan start point St to the widthwise center of the first lead 11 by counting the clock (CLK), and starts X samples. The start signal is sent to the A/D via the gate and timing adjustment section 41.
Add to converter 30. As a result, the distance measurement value at the widthwise center of the first lead 11 (output of the displacement meter controller 13) is A/D converted and written into the memory 33. At this time, the write address of the digitized distance measurement data into the memory is controlled by the start address designation counter 35 and the data selector 36. The distance measurement data corresponding to the widthwise center of the second and subsequent leads 11 is written to the memory using the sample pitch instruction counter 31.
By B counting the clock (CLK), X-Y
It is detected that the table 1 has moved by the distance Lp between the centers of adjacent leads in the width direction, and an X sample start signal is sent to the A/D converter 3 via the gate and timing adjustment section 41.
This is done by adding 0 to 0 corresponding to each lead.

The sample count instruction counter 31C receives the X sample start signal as a clock (CLK), counts the number of samples in the X-axis direction, detects that all the leads in the X-axis direction (one side) have been sampled, and then outputs the sample. An operation stop signal (ATE) is output to the start position designation counter 31A and the sample pitch designation counter 31B.

Next, when the scanning of the laser displacement meter 12 reaches the scanning end point in the X-axis direction, the NC controller 6 sends a signal to the X-Y table driving servo drive 5 to move the X-Y table 1 in the Y-axis direction. The Y-axis count pulse that indicates the movement of the X-Y table 1 in the Y-axis direction is output from the rotary encoder 3 on the X-Y table side, and the Y-axis force 9 is applied to the rotary encoder 3.
A clock (CL) is applied to the sample start position designation counter 32A and the sample pitch designation counter 32B in 2.
K). The sample start position designation counter 32A counts the clock (CLK) so that the X-Y table 1 determines the width of the first lead 11 in the Y-axis direction from the scanning start point in the Y-axis direction (scanning end point in the X-axis direction). When it is detected that the distance to the center of the direction has been moved, an X sample start signal is applied to the A/D converter 30 via the gate and timing adjustment section 41. As a result, the distance measurement value (
(output of the displacement meter controller 13) is A/D converted and written into the memory 33. The distance measurement data corresponding to the widthwise center of the second and subsequent leads 11 in the Y-axis direction is written to the memory by the sample pitch instruction counter 32B counting clocks (in CL).
Distance 1fi between the centers of adjacent leads in the width direction of Y table 1
This is carried out by detecting that the shift by Lp has occurred and applying an X sample start signal to the A/D converter 30 via the gate and timing adjustment section 41 in correspondence to each lead. The sampling number instruction counter 32C receives the X sample start signal as a clock (CLK), counts the number of samples in the Y-axis direction, detects that all the leads in the Y-axis direction (one side) have been sampled, and then outputs the sample. An operation stop (GATE) signal is output to the start position designation counter 32A and the sample pitch designation counter 32B.

The next scanning and sampling operation of the laser displacement meter 10 in the X-axis direction and the scanning and sampling operation of the laser displacement meter 10 in the Y-axis direction are performed in the same manner as in the above case.

Each time the A/D converter 30 converts the analog input from the displacement meter controller 13 into a digital signal, it applies a conversion completion signal as a clock (CLK) to a total number counter 34 that counts the total number of sampled data. As a result,
The counter 34 outputs a reset signal to the busy F/F 40 when the counted value matches the total number of reads. As a result, the busy output disappears, indicating that writing of the measurement data to the memory 33 has been completed.

In step #8 "measurement data extraction", the measurement data of the memory 33 corresponding to all the reads are sequentially read out and transferred to the NC controller 6 side via the VME bus.

Each measurement data stored in the memory 33 is the absolute value of the distance between the laser displacement meter 10 and the lead (the inclination of the flat electronic component 10 being sucked by the suction nozzle 2 is not taken into consideration). , Step #9 "Inclination calculation/averaging process" calculates the inclination of the flat electronic component 10 from all measurement data (for example, using the least squares method), and calculates the amount of change caused by the inclination included in the measurement data for each lead. Find relative value data by removing .

Step #10 ``Tolerance check'' checks the allowable range of the relative value data of each lead obtained in step #9, and in the next step #11 'No/GOJ, if there is a lead outside the allowable range (No ), the flat electronic component is mounted and the recovery process (processing such as lead correction of the flat electronic component) is performed. In addition, if the relative value data of all the leads is within the allowable range (in other words, if there is virtually no floating of the leads), the next step #12rX, Y
"Correction" and set the X-Y table 1 to ΔX in FIG.

The flat electronic component 10 is moved in a direction to offset ΔY, and the flat electronic component 10 is mounted on the printed circuit board by the downward movement of the suction nozzle 2 in step #13 "Component mounting".

The above steps #9 to #12 are executed under the control of the NC controller 6.

In the above embodiment, a case has been described in which the flat electronic component 10 moves to the imaging position of the imaging means in step #2, but the imaging means may move the imaging position to take an image of the flat electronic component 10. You can also do it.

Also, in step #7, the flat electronic component 10 was fixed and the laser displacement meter 10 moved, but conversely, the laser displacement meter 10 was moved.
There is no problem even if the 0 side is fixed and the flat electronic component 10 side is movable.

(Effects of the Invention) As explained above, according to the flat electronic component lead floating detection device of the present invention, by scanning a plurality of leads of a flat electronic component with a laser displacement meter facing each other, each The distance between the lead and the laser displacement meter, in other words, the floating of the lead can be detected with high precision (for example, about 20 μ-). In addition, flat electronic components can be held using a suction nozzle for mounting flat electronic components on a printed circuit board, and scanning with a laser displacement meter can be performed using an X-Y table on which the printed circuit board is mounted. Since it can be implemented, it can be realized with a simple and inexpensive mechanism. Furthermore, among the distance measurement values obtained by the laser displacement meter, the measurement value at the widthwise center of each lead, which has the most stable value, is sampled and sequentially stored in a memory, and floating of the lead is detected by mutually comparing the stored contents of the memory. With this configuration, lead floating can be detected at high speed even for flat electronic components having a large number of leads.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram showing an embodiment of a floating detection device for a flat electronic component lead according to the present invention, Fig. 2 is a diagram explaining the principle of a laser displacement meter, and Fig. 3 is an illustration of an analog sample controller used in the embodiment. A block diagram, FIG. 4 is a flowchart for explaining the operation of the embodiment, and FIG. 5 is a plan view showing a state before correction of Δθ, ΔX, and ΔY of a flat electronic component sucked and held by a suction nozzle. Figure 6 is a plan view showing the flat electronic component after Δθ correction, Figure 7 is an explanatory diagram showing the relationship between the laser displacement meter scanning direction and the distance measurement signal, and Figure 8 is the flat type electronic component with floating leads. FIG. 2 is a front view showing an example of an electronic component. 1... X-Y table, 2... Suction nozzle, 6...
・NC controller, 10...Flat type electronic component, 11
...Lead, 12...Laser displacement meter, 13...
Displacement meter controller, 14... Analog sample controller, 20... Laser light source, 23... One-dimensional PSD, 30... A/D converter, 31... X-axis counter section, 32... Y-axis counter section, 33...memory.

Claims (3)

[Claims] (1) A flat electronic component with a plurality of leads protruding along its sides is held by a suction nozzle, a laser displacement meter is placed so as to freely face the plurality of leads, and the suction nozzle and the laser displacement 1. An apparatus for detecting floating of a flat electronic component lead, characterized in that the laser displacement meter is scanned in a direction across the plurality of leads by relative movement of the meter. (2) A flat electronic component with multiple leads protruding along its sides is held by a suction nozzle, a laser displacement meter is fixed to an X-Y table so as to freely face the multiple leads, and the suction A floating detection device for flat electronic component leads, characterized in that the laser displacement meter is scanned in a direction across the plurality of leads by relative movement between a nozzle and the X-Y table. (3) The output of the laser displacement meter is amplified, the measured value at the center in the width direction of each lead is sequentially stored in a memory, and floating of the lead is detected by mutual comparison of the stored contents of the memory. The floating detection device for flat electronic component leads described above.