JP2630034B2 - Lead bending measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention measures the amount of lead bending in a direction in which a plurality of leads extend outward from an outer body of a surface mount integrated circuit device. Also, the present invention relates to a lead bending measuring device for measuring the same flatness (hereinafter, simply referred to as flatness) of a lead end surface.

[Conventional technology]

Conventionally, surface mount type integrated circuit device (hereinafter simply referred to as IC)
Was mounted by soldering the tips of the leads to the pads of the printed wiring board. In recent years, the number of IC leads has been increasing, and the pitch and position accuracy of printed circuit board pads have become stricter. For this reason, strict requirements have been placed on the bending and flatness of the leads. It has been done.

This lead bending measuring device is composed of a measuring device for measuring the lead bending in the direction in which the lead extends, and a bending device for the tip of the lead, that is, a flatness measuring device for the leading end surface of the lead. Have been. In this lead bending measurement inspection, first, one of the measuring devices is used to measure the bending in one direction, and then, the bending of the lead in a direction perpendicular to the one direction is measured. IC with unbent leads if both measured values are less than or equal to the criterion value
As good.

FIGS. 11, 12, and 13 are schematic diagrams each illustrating 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 flatness measuring device for the leading end of a lead, for example, as shown in FIG. Light is projected onto the area 2a, an image is captured by the area sensor camera 1 by the transmitted light, the image data is binarized, and a profile consisting of a group of bright points indicated by each lead 24 and a group of dark points indicated by the surface of the inspection stage 2a , And the maximum value was obtained 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, an image of the gap between the lead 24 and the inspection stage 2a is taken, and this gap is set to a maximum value. There is also a method of obtaining the flatness of a lead by searching.

Further, as shown in FIG. 13, an optical fiber array 34 is inserted between the lead 24 and the inspection stage 2a, the lead 24 is projected with light emitted from the optical fiber array 34, and the projected image is An image was taken by the camera 1 and the flatness of the lead was measured by the method described in the above example.

FIG. 14 is a diagram schematically illustrating an example of a measuring device for measuring a lead bending in a direction in which a lead extends in a conventional lead bending measuring device, and FIG. 15 illustrates an operation of the measuring device of FIG. Flow chart for explanation, FIG. 16 (a)
And (b) is a diagram for explaining the algorithm of the measuring device of FIG. On the other hand, as shown in FIG. 14, for example, as shown in FIG. 14, a measuring device for measuring the bending in the direction in which the lead of the IC is extended is equipped with an IC 3 and an inspection stage 2b made of a conductive glass plate. The light source 21 irradiates light from the back surface of the stage 2b, and the area sensor camera 1 captures an image of the lead 24 projected by light transmitted through the inspection stage 2b and diffused outside.

When measuring the bending of the lead with this measuring device, first, in (setting of windows 3 and 4) of FIG. 16 As shown in FIG.
Set to the imaging area of OW3 and WINDOW4. Then, (each WIND
OW vertical profile creation), area sensor camera 1
Captures the WINDOW area and performs light / dark binarization processing. As a result, as shown in FIG. 16 (b), a profile of the tip portion and the root portion of the lead is obtained. Next, search for the rising and falling points of the profile, e, f, g, and h
16 The coordinate points of e, f, g and h in FIG. Next, the midpoints m1 and m2 in FIG. 16 (b) are determined by the following equation in (calculation of midpoints, m1 and m2). That is, m1 = e + f / 2 and m2 = g + h / 2 were obtained, and then the bending amount of the lead was measured by (bending amount calculation m2−m1).

[Problems to be solved by the invention]

However, in the above-described conventional lead bending measuring apparatus, there is a disadvantage that the apparatus for measuring the bending of the lead and the flatness of the tip of the lead is independent of each other, and therefore the apparatus itself becomes large. In addition, since the measurement is performed twice, the number of contacts between the lead and the inspection stage increases, and there is a disadvantage that the plated surface of the lead is easily damaged.

On the other hand, the bending measuring apparatus shown in FIG. 14 has a drawback that an error in the measured value occurs due to the setting of the size of the WINDOW area and the amount of bending of the lead. For example, if the lead width is 20
0 μm, the protrusion amount from the outer shell of the lead is 700 μm, and if the actual bending angle is 12 degrees with respect to the direction in which the lead extends, the calculated amount of the measuring device is 140 μm for the actual bending amount of the lead. There is a problem that an error such as measurement of 90 μm occurs, and an erroneous determination of a defective product as a non-defective product occurs.

It is an object of the present invention to provide a lead bending measuring device which overcomes such disadvantages.

[Means for solving the problem]

A feature of the present invention is that a flat tip portion of a lead formed by extending and bending outwardly from the side surface of an outer package of a surface mount type integrated circuit device is placed on the front surface, and light enters from the rear surface side. A conductive white diffusing resin body for diffusing the light out of the other surface; and a space protruding from the front surface of the conductive white diffusing resin body and between the bent portion of the back surface of the lead and the outer body. A projection member for positioning the surface-mounted integrated circuit device, and the light diffused from the surface of the conductive white diffusion resin body is directed in a direction parallel to a direction extending outward of the lead by the projection member. Light splitting means for splitting light into light and light in a direction perpendicular to the direction; an image pickup mechanism for picking up projection images of respective parts of the lead by the light in these two directions; and binarization of image data of these image pickup mechanisms Binarization processing to process A profile processing mechanism for creating a projection contour of the lead by the image data subjected to the binarization processing; and a plurality of binarization data in the projection contour in a direction in which the lead extends by the light in the parallel direction. A first calculating mechanism for calculating the flatness of a plane formed by the tip of the lead, and the lead of the lead based on binarized data in a projection contour perpendicular to a direction in which the lead extends by the light in the vertical direction. A lead bending measuring device having a second calculating mechanism for calculating a bending amount in an extending direction.

Further, it is desirable that the second calculation mechanism performs a trigonometric function operation. Further, it is desirable that the imaging mechanism captures a linear projection image.

〔Example〕

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

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

The main part of the lead bending measuring apparatus in this embodiment is the first part.
As shown in FIG. 2 and FIG. 2, a conductive milky white, which is an inspection stage 2 for mounting the IC 3 on the front surface and receiving light from the light source 21 placed on the rear surface side and diffusing the light outside the other surface of the main body. As shown in FIG. 2, the diffusion resin body branches light into a lead 24 extending from the side surface of the outer body of the IC 3 in a direction in which the light extends and in a direction perpendicular to this direction, and forms these lights with different brightness. In addition, the projected image of each part of the lead 24 projected on the bidirectional light branched from the projection part 7 having an optical prism function formed on the surface of the inspection stage 2 via the prism 6 or the mirror 5 And an area sensor camera 1 which is an image pickup mechanism for picking up images.

Here, the conductive light milky-white diffusion resin 4 and the conductive dark milky-white diffusion resin 22 have different milk turbidities, and the light from the light source 21 passes through the two kinds of milky-white diffusion resins, thereby causing the light on the upper surface of the inspection stage 2. The brightness is changed. That is, if the light parallel to the surface of the inspection stage 2 has lower brightness than the light generated upward, the light emitted upward will cause irregular reflection,
Since the parallel light for measuring the flatness is consumed and an error occurs in the flatness measurement, the turbidity is designed so that the luminance becomes stronger.

Further, the metallic light shielding plate 23 is provided so that unnecessary light does not diverge. Further, the protrusion 7 is shaped so as to enter into the outer body of the IC and the curved portion of the lead 24, so that the IC 3 can be placed without any positional displacement with respect to the area sensor camera 1 and without correcting the angle.

On the other hand, in addition to the main part, as shown in FIG. 3, an image capturing unit 8 for capturing a projection image from the area sensor camera 1, an image memory 9 for temporarily storing the projection image data, and And a profile creation unit 12 that creates a projection contour of the lead 24 based on the binarized image data.
And a CPU 32 comprising an arithmetic processing unit and a storage unit.

The CPU 32 further includes a coplanarity calculation unit 13 that calculates the flatness of a surface formed by a plurality of tips of the leads based on the binarized data in the projected contour in the direction in which the leads extend,
A center value calculator 10 and a triangular calculator 11 which are lead bend calculators 33 for calculating the amount of bend in the direction in which the lead extends in accordance with the binarized data in the projected contour perpendicular to the direction in which the lead extends; Calculation unit 13 and bending amount calculation unit
The quality determination unit 14 determines the quality by comparing the result of 33 with the quality determination criterion stored in the external storage device 16.

Further, the CPU 32 has the I / O 1
External storage devices 15 and 16 for storing via the 7a and 17b, and a CRT 18 and a printer 19 for displaying the I / O 17c and 17d and printing out the calculation results and the determination results.
And a keyboard 20 for inputting determination criteria to the external storage device 16 via the I / O 17d.

FIG. 4 is a diagram for explaining an algorithm for calculating the flatness of the lead bending measuring device of FIG. 1, and FIGS.
Up to the figure, a flowchart for explaining a method of calculating a measured value, and FIG. 8 is a diagram for explaining a method of calculating a flatness.

Next, a measurement procedure and a measurement value calculation method of the lead bending measurement device will be described. First, a projected image by the light transmitted through the IC 3 is imaged by each area sensor camera 1.
Next, the projected image is captured by the image capturing unit 7, processed as, for example, 6-bit, 64-gradation multi-valued data, and temporarily stored in the image memory 9. Next, the stored multi-value data is binarized at a preset threshold level, and is stored again in the image memory 9 as binary data.

Next, to measure the flatness, the flatness is calculated from the images obtained by the area sensor cameras 1 at the four corners of the IC3.
To do this, as shown in FIG.
Profile and metal shading plate 23 (inspection stage surface)
Are stored in the image memory 9 as a group of dark points and as a group of bright points between the lead 24 and the inspection stage surface. Next, the profile creating unit 12 creates a bright spot group profile 35 composed of a bright spot group for each window 5 corresponding to each lead. Next, the coplanarity calculation unit 13 first searches 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 sets this as the flatness.
Next, this flatness value is stored in the external storage device 1 through the I / O 17a.
5 and sent to the pass / fail judgment unit 14 at the same time. Next, it is compared with a flatness determination criterion stored in the external storage device 16 to determine pass / fail.

Next, measurement of bending in the direction in which the lead extends will be described. As described above, first, the imaging areas WINDOW1 and WINDOW2 by the area sensor camera 1 are set in advance in step A of FIG. Next, in step B, the center value calculating unit 10 calculates the fourth value from the binarized image data.
FIG, WINDOW1 of one side L ₁ (a coordinate value WG1y) the intersection of the lead 24 a, and b, WINDOW2 of side L ₂ (coordinate values WG2y
) And the lead 24 are determined.

Next, the midpoints WG1, WG2 shown in FIG.
And the coordinates of point d.

 That is, WG1 (WG1x, WG1y) and WG2 (WG2x, WG2y) are obtained.

Next, in step C of FIG. 5, the bending angle θ shown in FIG. 4 is calculated.

That is, Ask for.

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

The calculation flow for obtaining the coordinates of STP and SBP is calculated by the triangular operation unit 11 using the trigonometric function from the bending angle θ, as shown in FIGS. 6 and 7.

The bending amount of each lead determined in this way is I / O 17a
And is stored in the external storage device 15. The maximum value of the bending amounts of the leads is sent to the pass / fail judgment unit 14. Next, the external storage device 16 for standard data accumulates the judgment reference value of the lead bending amount and the judgment reference value of the flatness input from the keyboard 20 via the I / O 17d.

Next, the pass / fail judgment unit 14 compares the lead bending amount and flatness sent from the triangular operation unit 11 and the coplanarity calculation unit 13 with the judgment reference value of the external storage device 16 sent via the I / O 17b. , The quality of the measurement result is determined. Then, the quality is stored in the external storage device 15. Also, CR
At T18, the printer 19 displays and outputs data and measurement results from the external storage devices 15 and 16 via the I / Os 17c and 17d.

FIG. 9 is a diagram for explaining a main part of a lead bending measuring device showing another embodiment of the present invention, and FIG. 10 is a block diagram showing an entire configuration of the lead bending measuring device of FIG.
As shown in FIGS. 9 and 10, the lead bending measuring device in this embodiment is a line sensor camera instead of the area sensor camera described in the above embodiment. Then, the line sensor camera 25 is moved from the lead 24 on one end side of the IC 3 to the lead 24 on the other end side, scans each lead surface, receives linear transmission light, captures an image, and This is to measure the bending of the lead in the direction in which the lead extends and the flatness of the tip of the lead by binarizing the imaging data and performing arithmetic processing in the same manner as in the above-described embodiment.

For this reason, as shown in FIG. 9, two line sensor cameras 25 for imaging the leads on one side of IC3 are housed in one block, and a ball screw 31 for moving this block along the side of IC3. And a nut, and a servomotor 27 for rotating the ball screw 31 is attached. Further, a linear scale 26 and a servomotor 27 for detecting the position of the line sensor camera 25, a decoder 29 for reading the linear scale 26, 29 by 28 driver
And a controller 30 for controlling the

Of course, in this drawing, the leads 24
Are projected, so that four pairs of blocks and drive mechanisms for moving the line sensor camera 25 are provided. In addition, in order to accommodate the line sensor camera for imaging the lead 24 in the same block, a prism 6a, 6b, 6c and a mirror 5a are provided in front of the line sensor camera 25 for imaging the lead surface in order to change the optical path. Is provided. In FIG. 9, the direction of the ball screw 31 is shifted by 90 degrees from the actual direction due to space limitations.

Further, in this lead bending measuring apparatus, a controller 30 for controlling the position of the line sensor camera 25 is connected to a CPU 32, as shown in FIG. Otherwise, the configuration including the image capturing unit 8 is the same as that of the above-described embodiment.

Next, the operation of the lead bending measuring device will be described. First, one of the transmission images at the lead 24 of the IC 3 is a mirror 5
The other transmitted image enters one of the line sensor cameras 25 via the prisms 6a, 6b, 6c and the mirror 5a, and is picked up. At this time, the block containing the line sensor camera 25 is
It is sent in one direction by 27 and a ball screw 31, and each lead 24 is sequentially imaged. Next, these projection images are captured by the image capturing unit 7 and binarized by the binarization processing unit 8a. Next, similarly to the above-described embodiment, data processing and calculation are performed, the bending of the lead and the flatness are measured, and the pass / fail is determined by comparison with a criterion.

The lead bending measuring apparatus of this embodiment is different from that of the above-described embodiment in that the width in the scanning direction is set as a slit-shaped line and a line sensor camera having a high horizontal resolution is used instead of imaging the area. This has the advantage that the measurement accuracy of the lead bending amount can be further improved. Also, since it is not limited by the field of view of the sensor camera,
There is also an advantage that it can be applied to larger ICs.

〔The invention's effect〕

As described above, the present invention provides an optical mechanism that simultaneously generates light that is transmitted in the direction in which the lead extends and light that is transmitted in a direction perpendicular to this direction, and two imaging devices that capture a projected image of the lead using these transmitted light. A mechanism is provided for binarizing the image data, calculating the image data in one direction to obtain the flatness of the tip of the lead, and performing the trigonometric function operation on the image data in the other direction to calculate the direction in which the lead extends. There is an effect that a small lead bending measuring device capable of simultaneously measuring the bending, the bending in the direction in which the lead extends, and the same flatness of the tip of the lead, and more accurately determining the bending can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view showing the structure of a main part of a lead bending measuring apparatus showing an embodiment of the present invention, FIG. 2 is a view for explaining an optical path in the lead bending measuring apparatus of FIG. 1, and FIG. FIG. 4 is a block diagram showing the overall configuration of the lead bending measuring device of FIG. 1, FIG. 4 is a diagram for explaining an algorithm for calculating the flatness of the lead bending measuring device of FIG. 1, and FIGS. Up to the figure, a flowchart for explaining a method of calculating a measured value, FIG. 8 is a diagram for explaining a method of calculating flatness, and FIG. 9 is a lead bending measurement showing another embodiment of the present invention. FIG. 10 is a diagram for explaining the main part of the device, FIG. 10 is a block diagram showing the entire configuration of the lead bending measuring device of FIG. 9, and FIGS. 11, 12, and 13 are conventional lead bending measuring devices. Of an example of a measuring device for measuring the flatness of the tip end surface of a lead in Each diagram showing an outline of a fit, 14
FIG. 1 is a diagram schematically illustrating an example of a measuring device for measuring lead bending in a direction in which a lead extends in a conventional lead bending measuring device. FIG. 15 illustrates the operation of the measuring device in FIG. FIGS. 16 (a) and (b) are diagrams for explaining the algorithm of the measuring apparatus of FIG. 1 area sensor camera, 2, 2a, 2b inspection stage, 3 IC, 4 conductive milky white diffusion resin, 5 5a
...... Mirror, 6, 6a, 6b, 6c ... Prism, 7 ... Protrusion, 8 ... Image capturing unit, 8a ... Binarization processing unit, 9 ...
Image memory, 10: Central value calculation unit, 11: Triangular operation unit,
12: profile creation unit, 13: coplanarity calculation unit, 14: pass / fail judgment unit, 15, 16 ... external storage device, 17
a, 17b, 17c, 17d …… I / O, 18 …… CRT, 19 …… Printer, 20 …… Keyboard, 21 …… Light source, 22 …… Conductive dark 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, 30
…… Controller, 31 …… Ball screw. 32 …… CPU, 33
…… lead bending calculator, 34 …… optical fiber array, 35…
… Bright point cloud profile.

Claims (3)

(57) [Claims] 1. A flat end portion of a lead, which is extended and bent from the side surface of an outer package of a surface mount type integrated circuit device, is placed on the front surface, and light enters from the rear surface side. A conductive white diffusion resin body for diffusing the light out of the other surface, and a space protruding from the surface of the conductive white diffusion resin body and entering the space between the bent portion of the back surface of the lead and the outer shell; A projection member for positioning the surface-mounted integrated circuit device, and the light diffused from the surface of the conductive white diffusion resin body is directed in a direction parallel to a direction extending outward of the lead by the projection member. A light branching means for branching light into a direction perpendicular to the direction, an image pickup mechanism for picking up an image of each part of the lead by the light in these two directions, and a binarization process of image data of the image pickup mechanism. Binarization processing machine A profile processing mechanism for creating a projected contour of the lead by the image data subjected to the binarization processing; and a plurality of the binary data in the projected contour of the lead extending direction by the light in the parallel direction. A first calculating mechanism for calculating the flatness of a plane formed by the tip of the lead; and the lead extending by the binary light in a projection contour perpendicular to the direction in which the lead extends by the vertical light. And a second calculating mechanism for calculating a bending amount in a direction. 2. The lead bending measuring apparatus according to claim 1, wherein said second calculating mechanism performs a trigonometric function operation. 3. The lead bending measuring apparatus according to claim 1, wherein the imaging mechanism captures a linear projection image.