JPH0480937A - Lead bending measuring device - Google Patents

Abstract

PURPOSE:To enable the bending in the lead extending direction as well as the coplanarity of the bending in the lead extending direction and the end of lead to be simultaneously measured by a method wherein the planarity of the end of multiple leads is counted by the binary data at the projection outline in the lead extending direction while the bending amount in the lead stretching direction is counted by the binary data at the projection outline in the orthgonal direction to the lead extending direction. CONSTITUTION:A CPU 32 is composed of the components enumerated as follows a coplanarity counter 13 counting the planarity of the surface comprising the ends of multiple leads by the binary data at the projection outline in the lead stretching direction; a central value counter 10 and a trigonometric processor 11 comprising a lead bending amount counter 33 counting the bending amount in the lead stretching direction by the binary data at the projection outline in the orthogonal direction to the lead stretching direction; and an acceptability judgement part 14 making the acceptability judgement by making comparison between the results from the coplanarity counter 13 and the bending amount counter 33 and the acceptability judgement reference stored in an outer memory 16.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention measures the amount of lead bending in the extending direction of a plurality of leads extending outward from the outer shell of a surface mount integrated circuit device. The present invention also relates to a lead bending measuring device for measuring the coplanarity (hereinafter simply referred to as flatness) of the tip end surface of a lead.

[Conventional technology]

Conventionally, surface-mounted 4AM circuit devices (hereinafter simply referred to as fC) have been mounted by soldering the tips of leads to pads on a printed wiring board. In addition, recently, the number of IC leads has been increasing, and the pitch spacing and positional accuracy of the pads on printed wiring boards have become stricter.Therefore, strict requirements have also been placed on the bending and flatness of the leads. It has come to be done.

This lead bend measuring device consists of a measuring device that measures lead bending in the direction in which the lead extends, and a measuring device that measures the bending of the lead tip.
That is, it is composed of two types of measuring devices: a flatness measuring device for the tip end surface of a lead. In addition, in this lead bend measurement test, first measure the bend in one direction using one of the measuring devices, then measure the bend of the lead in a direction perpendicular to this one direction, and The measured value was compared with each judgment reference value, and if both of the measured values were less than the judgment reference value, the IC was considered to be a good product as having an unbent lead.

FIGS. 11, 12, and 13 are diagrams each schematically showing an example of a measuring device for measuring the flatness of the tip end surface of a lead in a conventional lead bending measuring device. Conventionally, as an example of this type of lead tip flatness measuring device, as shown in FIG. 2a, the transmitted light is used to capture an image with the area sensor camera 1, and this captured data is binarized to create a profile consisting of bright spot areas indicated by each lead 24 and a dark spot group indicated by the surface of the inspection stage 2a. The distance between the lead and the profile was calculated, and the maximum value was found from all the calculated results, which was taken as the flatness of the lead.

Further, using a measuring device as shown in FIG. 12, for example, the light source 21 is irradiated from the other end side of the IC 3, and
There is also a method of determining the flatness of the lead by imaging the gap between the lead and the inspection stage 2a and searching for the maximum value of this gap.

Furthermore, as shown in FIG. 13, an optical fiber array 34 is inserted between the leads 24 and the inspection stage 2a, and the leads 24 are projected with light emitted from the optical fiber array 34, and this projected image is sent to the area sensor. An image was taken with camera 1, and the flatness of the lead was measured using the method described in the above example.

FIG. 14 is a diagram schematically showing an example of a conventional lead bending measuring device that measures lead bending in the direction in which the lead extends, and FIG. 15 shows the operation of the measuring device shown in FIG. 16 (a> and (b)) are diagrams for explaining the algorithm of the measuring device shown in FIG. 14. On the other hand, in the direction in which the IC leads extend For example, as shown in FIG. 14, a measuring device for measuring bending includes an inspection stage 2b mounted with an IC 3 and made of a conductive glass plate, etc., and a light source 21 that irradiates light from the back side of this inspection stage 2b. and an area sensor camera 1 that captures an image of the lead 24 projected by light transmitted from the inspection stage 2b and diffused to the outside.

When measuring the bending of a lead with this measuring device, first, the imaging area of the root of the lead 24 and the imaging area of the tip of the lead are set to As shown in Figure 16 (a), set the imaging areas of WINDOW 3 and WINDOW 4 for the lead 24.Next, in (Creating 10 vertical files for each WINDOW), image the WINDOW area with the area sensor camera 1 and set the bright and dark areas. The 16th
As shown in Figure (b), the 7th order (rise of the profile,
16(b)
Find the coordinate points e, f, g, and h of (midpoint,
ml, m2 calculation), and the midpoints m1 and m of Fig. 16(b)
2 is calculated using the following formula. That is, m l = e 10f, /2, m 2 = g +
Find h/' 2, then (calculate the amount of bending m2 - m1)
I was measuring the amount of bending of the lead.

[Problem to be solved by the invention]

However, the conventional lead bending measuring device described above has a drawback that the device itself becomes large because the devices that measure the bending of the lead and the flatness of the tip of the lead are independent. In addition, since the measurement is carried out in two parts, the number of times the lead contacts the inspection stage increases, and the plated surface of the lead is easily damaged.

On the other hand, in the bending measuring device shown in FIG.
There is a drawback that errors in measurement values occur due to the setting of the size of the W area and the bending of the lead. For example, the width of the lead is 200μm, and the amount of protrusion from the lead outer shell is 700μm.
m, the actual bending angle is 12
If this were the case, there would be an error in that the calculated amount of the measuring device would measure 90 μm compared to the actual bending amount of the lead of 140 μm, resulting in a problem that a defective product would be erroneously judged as a non-defective product.

An object of the present invention is to provide a lead bending measuring device that eliminates such drawbacks.

[Means to solve the problem]

1. The first lead bending measuring device of the present invention includes an inspection stage that places an IC on the front surface of a main body, enters light from the back surface, and diffuses the light outside the other surface of the main body, and an optical mechanism formed on the surface of the inspection stage, which splits the light into two directions in the direction in which the lead extends from the side surface and in a direction perpendicular to this direction, and forms these lights with different brightness; an imaging mechanism that captures projected images of each part of the lead projected in the direction of light; a binarization processing mechanism that binarizes the image data of these projected images; a profile processing mechanism that creates a projected contour of the lead based on image data; and a profile processing mechanism that calculates the flatness of a surface formed by the distal end surfaces of the plurality of leads using binarized data on the projected contour in the extending direction of the lead. and a second calculation mechanism that calculates the amount of bending in the extending direction of the lead based on binarized data on the projected contour in the direction perpendicular to the extending direction of the lead. There is.

2. The second lead bending measuring device of the present invention is characterized in that the second calculation mechanism performs trigonometric function calculations.

3. The third lead bending measuring device of the present invention has a shape in which the optical mechanism is inserted into a bent part between the tip end of the lead and a part protruding from the outer shell, and protrudes from the surface of the inspection stage. It is characterized by certain things.

4. The fourth lead bending measuring device of the present invention is characterized in that the imaging mechanism captures a linear projected image.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a perspective view showing the structure of the main part of a lead bend measuring device showing one embodiment of the present invention, FIG. 2 is a diagram for explaining the optical path in the lead bend measuring device shown in FIG. 1, and FIG. 2 is a block diagram showing the overall configuration of the lead bending measuring device shown in FIG. 1. FIG.

As shown in FIGS. 1 and 2, the main parts of the lead bending measuring device in this embodiment include an IC 3 placed on the front surface and light entering from a light source 21 placed on the back surface of the main body. As shown in FIG. 2, there is a conductive milky white diffusion resin body which is the inspection stage 2 that diffuses the light out of the plane, and a lead 24 extending from the side surface of the outer body of the IC 3 in the direction in which it extends and at right angles to this direction. A protrusion 7 having an optical prism function is formed on the surface of the inspection stage 2 to split light in different directions and form the light into different brightnesses, and a lead is projected onto the light in these two directions. It has an area sensor camera 1 which is an imaging mechanism that captures a projected image of each part of 24 through a prism 6 or a mirror 5.

Here, the conductive milky-white diffusion resin 4 and the conductive milky-white diffusion resin 22 have different emulsities, and the light from the light source 21 passes through the two types of milky-white diffusion resin 2 and reaches the upper surface of the inspection stage 2. The brightness of the image is changed. That is,
If the light parallel to the surface of the inspection stage 2 is weaker in brightness than the light emitted above, it will cause diffuse reflection with the light emitted above, and the parallel light used to measure flatness will be eaten up, causing problems in flatness measurement. , to make the brightness stronger, as this will cause an error.
The turbidity is designed.

Further, the metallic light shielding plate 23 is provided to prevent unnecessary light from being emitted. Furthermore, the protrusion 7 has a shape that fits into the curved part of the outer body of C and the lead 24, and the IC 3 can be placed thereon without positional deviation or angle correction with respect to the area sensor camera 1.

On the other hand, in addition to this main part, as shown in FIG. Consists of a binarization processing unit 8a that binarizes data, a profile creation unit 12 that creates a projected contour of the lead 24 from these binarized image data, and a CPU 32 that includes an arithmetic processing and storage unit. be done.

The CPU 32 also operates a coplanarity calculation unit 13 that calculates the flatness of a surface formed by the distal end surfaces of a plurality of leads using binarized data on projected contours in the extending direction of the leads.
and a center value calculation unit 1 which is a lead bending calculation unit 33 that calculates the amount of bending in the lead extension direction based on binary data on the projected contour in the direction perpendicular to the lead extension direction.
0 and trigonometric calculation unit 11, and a quality determination unit 14 that determines quality by comparing the results of the coplanarity calculation unit 13 and the curved violet calculation unit 33 with the quality determination criteria stored in the external storage device W16.
It consists of

Furthermore, this CPU 32 has an I
/017a and 17b to store the calculation results and judgment results in the external storage devices 15 and 16 and I/017.
It has a CRT 18 for displaying and printing out 017c and 17d, a printer, and a keyboard 20 for inputting judgment criteria into the external storage device 16 via 110L7d.

FIG. 4 is a diagram for explaining the algorithm for calculating the flatness of the lead bending measuring device shown in FIG. FIG. 8 is a diagram for explaining a method for calculating flatness.

Next, the measurement procedure and measurement value calculation method of this lead bending measuring device will be explained. First, a projected image of light transmitted through the IC 3 is captured by each area sensor camera 1.

Next, this projected image is captured by the image capturing section 7, processed as, for example, 6-bit, 64-gradation multivalued data, and then stored in the image memory 9. Next, this accumulated multivalued data is binarized at a preset threshold level, and is again stored in the image memory 9 as binary data.

Next, to measure the flatness, the flatness is calculated using images obtained by the area sensor cameras 1 at the four corners of the IC 3.

As shown in FIG. 8, the profile of the lead 24 in the WINDOW 5 and the metallic light-shielding plate 23 (inspection stage surface) are imaged as a group of dark fish, and the area between the lead 24 and the inspection stage surface is imaged as a group of bright points. It is stored in memory 9. Next, the profile creation unit 12 creates a bright point group profile 35 consisting of a bright point group for each WINDOWS corresponding to each lead. Next, the coplanarity calculation unit 13 first searches for the minimum value of the vertical height for each WINDOW 5, extracts the maximum value among the minimum values for all the WINDOWs 5, and uses this as the flatness. Next, this flatness value is stored in the external storage device 15 through l1017a and simultaneously sent to the quality determining section 14. Next, it is compared with the flatness criteria stored in the external storage device 16 to determine whether it is good or bad.

Next, measurement of bending in the direction in which the lead extends will be explained. Also, as mentioned above, the imaging areas WINDOW1 and WINDOW2 by the area sensor camera 1 are set in advance in step A of FIG. 5, and then in step B.
From the binarized imaging data, the center value calculation unit 10 calculates the intersections a, b, and
Find the intersections C and d between one side L2 (coordinate value WG2y) of IND-〇W2 and the lead 24.

Next, the midpoints WGI and WG2 shown in FIG. 4 are set to the above a and b.
, calculated from the coordinates of points c and d.

That is, WG 1 (WG 1 x, WG 1 y >, WG 2
Find (WG2x, WG2y).

Next, in step C of FIG. 5, the bending angle θ shown in FIG.
Calculate.

That is, WG 2 x - WG l x θ=a rctan WG2y-WGly seek.

Next, in step E, the coordinate values of STP in FIG. 4 are determined. Subsequently, the coordinate values of SBP are determined using step F. Then, in step G, the amount of bending is calculated.

Note that the calculation flow for determining the respective coordinates of STP and SBP is as shown in FIGS. 6 and 7, in which the trigonometric calculation unit 11 calculates the coordinates from the bending angle θ using trigonometric functions.

The amount of bending of each lead obtained in this way is: ■/'01
−/a is returned and stored in the external storage device 115. Further, the maximum value among the amounts of bending of each lead is sent to the quality determining section 14. Next, the external storage device 16 for standard data is
The lead surface level determination reference value and the flatness determination reference value inputted from the keyboard 20 via 1017d are accumulated.

Next, the pass/fail determining section 14 calculates the bending amount and flatness of the lead sent from the trigonometric calculation section 11 and the coplanarity calculation section 13, and the external storage device W16 sent via T1017b.
The quality of the measurement results is determined by comparing them with the determination reference values. Then, the quality information is stored in the external storage device 15. Further, the CRT 18 and printer 19 display and output data and measurement results from the external storage devices 15 and 16 via I, 1017c and 17d.

FIG. 9 is a diagram for explaining the main parts of a lead surface measuring device showing another embodiment of the present invention, and FIG. 10 is a block diagram showing the overall configuration of the lead surface measuring device shown in FIG. be.

The lead surface measuring device in this embodiment, as shown in FIGS. 9 and 10, uses a line sensor camera instead of the area sensor camera described in the previous embodiment.

Then, the line sensor camera 25 is moved from the lead 24 at one end of the IC 3 to the lead 24 at the other end, scans each lead surface, and images the linear transmitted light. The purpose of this method is to measure the bending of the lead in the direction in which the lead extends and the coplanarity of the tip of the lead by converting the imaged data into values and performing arithmetic processing in the same manner as in the above-described embodiments.

Therefore, as shown in FIG. 9, two line sensor cameras 25 that image the leads on one side of the IC 3 are housed in one block, and a ball screw 31 moves this block along the side of the IC 3. and a nut, and a servo motor 27 for rotating this ball screw 31 is attached.Furthermore, a linear scale 26 and a servo motor 27 for detecting the position of the line sensor camera 25, a decoder 29 for reading this linear scale 26, and this decoder are provided. 29 and a controller 30 for controlling the driver 28.

Of course, in this drawing, leads 2 are connected from each of the four corners of IC3.
4 protrudes, so four pairs of blocks and drive mechanisms for moving this line sensor camera 25 are provided. Furthermore, in order to accommodate the line sensor camera that images the lead 24 in the same block, prisms 6a, 6b, 6C and a mirror 5a are installed in front of the line sensor camera 25 that images the lead surface in order to change the optical path. It is provided. In addition, in FIG. 9, the direction of the ball screw 31 is shown shifted by 90 degrees from the actual direction due to space limitations.

Furthermore, as shown in FIG. 10, in this lead bending measuring device, a controller 30 that controls the position of the line sensor camera 25 is connected to a CPU 32. Other than that,
The subsequent configuration including the image capturing section 8 is the same as the previous embodiment.

Next, the operation of this lead bend measuring device will be explained. First, one of the transmitted images in the IC3 board 24 is sent to one of the line sensor cameras 25 via the mirror 5, and the other transmitted image is sent to the other line sensor via the prisms 6a, 6b, 6c and the mirror 5a. The light enters the camera 25 and is imaged. At this time, the block housing the line sensor camera 25 is sent in one direction by the servo motor 27 and the ball screw 31 to sequentially image each lead 24. Next, these projected images are captured into the image capturing section 7, and the binarization processing section 8a
It is binarized by Next, as in the previous embodiment, data is processed, calculations are performed, bending and flatness of the lead are measured, and the results are compared with criteria to determine quality.

The lead bending measuring device of this embodiment differs from that of the previous embodiment in that it uses a slit-like line with a certain width in the scanning direction, and uses a line sensor camera with high horizontal resolution, rather than imaging an area. , there is an advantage that the measurement accuracy of the amount of lead bending can be further improved. Also,
Since it is not limited by the field of view of the sensor camera, it also has the advantage of being applicable to larger RCs.

〔Effect of the invention〕

As explained above, the present invention includes an optical mechanism that simultaneously splits and generates light transmitted in the direction in which the lead extends and light transmitted in a direction perpendicular to this direction, and two imaging systems that capture a projected image of the lead using these transmitted lights. A mechanism is installed to binarize these imaging data, calculate the flatness of the lead tip by processing the imaging data in one direction, and calculate the flatness of the lead tip by trigonometrically processing the imaging data in the other direction. This has the effect of providing a compact lead bend measuring device that can simultaneously measure the bend, the bend in the direction in which the lead extends, and the coplanarity of the tip of the lead, and can more accurately determine the bend.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the structure of the main part of a lead bend measuring device showing one embodiment of the present invention, FIG. 2 is a diagram for explaining the optical path in the lead bend measuring device shown in FIG. 1, and FIG. is a block diagram showing the overall configuration of the lead bending measuring device shown in FIG. 1, FIG. 4 is a diagram for explaining an algorithm for calculating the flatness of the lead bending measuring device shown in FIG. The figures up to the figure are flowcharts for explaining the method of calculating measured values, Fig. 8 is a figure for explaining the method of calculating flatness, and Fig. 9 is a lead bending measurement showing another embodiment of the present invention. A diagram for explaining the main parts of the device, FIG. 10 is a block diagram showing the overall configuration of the lead bending measuring device of FIG. 9, and FIGS. 11, 12, and 13 are diagrams of the conventional lead bending measuring device. Fig. 14 is a diagram schematically showing an example of a measuring device for measuring the flatness of the tip end surface of a lead in a conventional lead bending measuring device. FIG. 15 is a schematic diagram for explaining an example of the device; FIG. 15 is a flow chart diagram for explaining the operation of the measuring device in FIG. 14;
Figures 6 (a> and (b) are diagrams for explaining the algorithm of the measuring device in Figure 14. ■...Area sensor camera, camera, 2.2a, 2b...
Inspection stage, 3...-IC14... Conductive milky white diffusion resin, 5.5 a-Mirror, 6.6a, 6b, 6c
... Prism, 7... Protrusion, 8... Image capture section, 8a... Binarization processing section, 9-... Image memory, 1
o... Center value calculation unit, 11... Trigonometric calculation unit, 12.
... Profile creation section, 13... Coplanarity calculation section, 14... Quality determination section, 15.16... External storage device, 17a, 17b, 17c, 17d-Ilo, 1
8-CRT, 19... Printer, 20... Keyboard, 21... Light source, 22... Conductive milky white diffusion resin, 23... Metallic light shielding plate, 24...- Lead, 25...
...Line sensor camera, 26...Linear scale,
27... Servo motor, 28... Driver, 29...
... Decoder, 3o... Controller, 31... Ball connection. 32... CPU, 33... Lead bend calculation unit, 34... Optical fiber array, 35... Bright point group profile.

Claims (1)

[Claims] 1. An inspection stage that places a surface-mounted integrated circuit device on the front surface of a main body, enters light from the back surface, and diffuses the light outside the other surface of the main body; and the surface-mounted integrated circuit. An optical system that splits the light into two directions in the direction in which the lead extends from the side surface of the outer body of the apparatus and in a direction perpendicular to this direction, and forms these lights with different brightness, and is formed on the surface of the inspection stage. a mechanism, an imaging mechanism that captures projected images of each part of the lead projected by light in these two directions, and a binarization processing mechanism that binarizes image data of these projected images; a profile processing mechanism that creates a projected contour of the lead using digitized image data; and a profile processing mechanism that creates a projected contour of the lead in the direction in which the lead extends; and a second calculation mechanism that calculates an amount of bending in the extending direction of the lead based on binary data on a projected contour in a direction perpendicular to the extending direction of the lead. A lead bending measuring device featuring: 2. The lead bending measuring device according to claim 1, wherein the second calculation mechanism performs trigonometric function calculations. 3. Claims 1 and 2 characterized in that the optical mechanism has a shape that is inserted into a bent part between the tip end of the lead and a part protruding from the outer body and protrudes from the surface of the inspection stage. lead bend measurement device. 4. The lead bending measuring device according to claims 1, 2, and 3, wherein the imaging mechanism captures a linear projection image.