JPH02290504A - Method for detecting curve of ic lead - Google Patents

Abstract

PURPOSE:To detect the curve of an IC lead from whether or not there are generated pulses and their intervals at a high speed with high accuracy by making a light beam scan a lead arrays and cutting off the laser beam by the leads. CONSTITUTION:When an IC 13 is conveyed in a set direction at a constant speed, the laser beam from a laser light source for flotation detection makes an irradiation scan relatively along a straight line 16B set at a proper position outside a straight lines 16A connecting the tips of the leads in the normal state. At the same time, the laser beam from a laser light source for sinking detection makes an irradiation scan relatively along a straight line 16C set at a proper position inside the straight line 16A. At the same time, the laser beam from the laser light source for flotation detection is photodetected by a photodetecting element for flotation detection without being cut off by the leads 14A - 14D unless the leads 14A - 14D curve upward or downward. At the same time, the laser beam from the laser light source for sinking detection is cut off when striking on the leads 14A - 14D and their shadows appear on the photodetecting element.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for detecting bending of an IC lead, and particularly to a method of detecting bending of an IC lead by using a light beam to detect bending of an ICU lead (up, down, down) and left/right (lead). The present invention relates to a detection method for quickly detecting bending in the column direction with high accuracy.

[Conventional technology]

FIG. 9 is a diagram of a conventional IC lead bending inspection device.

In the figure, l is a surface mount type IC (semiconductor integrated circuit device) whose leads are bent in two stages, and 2 is the rc1.
3 is a light source for illumination;
4 is a TV camera.

In this detection device, ICI is guided and transferred by a guide 2,
When it enters the field of view of TV camera 4, the image will be seen by TV camera 4.
is loaded into. This image is binarized and the coordinates of the tip of each lead of the IC are calculated to detect vertical and horizontal bending of the lead.

[Problem to be solved by the invention]

In this way, conventionally, lead bending is detected from the IC image obtained with a TV camera, so the accuracy is limited by the TV camera's depth of focus, resolution, and lead surface condition, and high-speed processing is required. The problem was that it was not possible.

The present invention was made to solve the above problems, and
[An object of the present invention is to provide a detection method that can detect bends in C leads with high precision and high speed.

[Means to solve the problem]

To this end, the present invention provides a sunken detection light beam that relatively scans a straight line set inside a straight line connecting the tips of a plurality of IC leads arranged in a row when they are in a normal shape, and A floating detection light beam that relatively scans a straight line set on the outside is used to detect the downward bending of the IC lead and the floating detection light beam because the sunken detection light beam is not blocked by the IC lead. The upward bending of the I C +J lead was detected by blocking the detection light beam by the IC lead.

〔Example〕

Hereinafter, a method for detecting bending of an IC lead according to an embodiment of the present invention will be described. FIG. 1 is an explanatory diagram of a detection device for carrying out the detection method. In the figure, 10 is a laser light source fixed to a support, II is a laser beam emitted from the laser light source 10 (for example, wavelength 780 nm, spot diameter 50 μm) 12 is a light receiving element that receives the laser beam 11, and 13 is a light receiving element in the figure. Guided transfer in the direction that intersects the paper surface (
For example 3 5. 8 mm/s) with an IC that allows
Each side of the IC package has a plurality of (4 in this example)
lead 14 (14A-D and 14E~ in Figure 2)
H) is arranged in a protruding manner.

The pair of laser light source 10 and light receiving element 12 constitutes one set of detection section. In this example, this detection part is used for floating detection,
Two sets for sinking detection are provided along both sides of the IC, for a total of four sets. The one for floating detection is provided on the outside, and the one for sinking detection is provided on the inside. In FIG. 1, only two sets are shown, one on each side of the IC, and the others are omitted.

FIG. 3 is an enlarged side view of the IC 13. Now lead 14
If it is bent upward as shown in Fig. 3 (bl) by l4°, its tip will be on the outside, that is, the IC buff cage l.
biased away from 5. On the contrary, in Fig. 3 (sign 1 in Cl)
When it is bent downward as shown by 4'', its tip is biased inward, that is, toward the IC path cage 15 side. The relationship between the amount of change in the vertical direction and the amount of deformation in the X direction (horizontal direction) is shown in FIG.

In FIG. 4, for the lead 14 on the white circle lead 14A-D row side, the black circle lead 14E-H row side lead 1
4, and the amount of X indicates the horizontal distance from the tip of the normal lead. For example, lead 14
When the tip of the glue 14 on the A-D row side deforms upward by h1, the amount of X becomes X,.

In this example, the bending of the lead is detected from this amount of X, and those whose bending exceeds a certain limit value are judged to be defective. The defective limit value for ups and downs in the vertical direction is 1/2 of the lead thickness (0.15 mm). In addition,
For the left and right directions to be described later, the lead width (0.35 mm) is 172.

Now, in this example, the detection of the presence or absence of bending of the IC lead 14 is as follows.
This is done simultaneously for both the lead 14A-D row and the lead 14E-H row, so in the following explanation, the lead i4A-D row will be explained, and the lead 14E-H row will be explained.
Columns are omitted.

First, when the rc13 is moved at a constant speed in the set direction, as shown in FIG. A laser beam from a laser light source for floating detection is relatively irradiated and scanned. At the same time, a laser beam from a laser light source for sinkage detection is relatively irradiated and scanned along a straight line 16C set at an appropriate position (limit value position) inside the straight line 16A.

At this time, if each lead 14A-D is not bent in the vertical direction, the laser beam from the laser light source for floating detection will not be blocked by each lead 14A-D, and will be directly received by the lead 14A-D. The light is received by the element. At the same time, the laser beam from the laser light source for sinkage detection is interrupted (when irradiated) with each lead 14A to D, and its shadow appears on the light receiving element.

FIGS. 5 to 8 are waveform diagrams in which such shadows are converted into pulse counts. In FIG. 5, it can be seen that there is no vertical bending in each lead 14A-D. In other words, straight line 16
When the laser beam was scanned relatively along B, no pulse was generated in the light receiving element for floating detection (Fig. 5 fal)
, when scanning along the straight line 16C, four pulses are generated in the light-receiving element for sinking detection (FIG. 5(bl)), which indicates that there is no vertical bending in each lead 14'A-D.

Next, if each of the leads 14B, C, and D has an upward bend exceeding a limit value, the laser beam from the laser light source for floating detection is blocked by these leads B, C, and D.
3 pulses are generated (Fig. 6(a)), and leads 14B, C
, D has a defective upward bend.

In addition, if the lead 14A is bent downward by more than the limit value, the lead 14A will sink and will not block the laser beam from the laser light source for detection and will not generate pulses (see Figure 3). See C).

As a result, as shown in FIG. 6(b), only three pulses are generated, with the pulse from lead 14A missing.
It can be seen that there is a bending defect.

Next, the horizontal bending of the lead 14 is detected simultaneously by comparing the pulse interval obtained by the above detection with a set value (normal value). That is, each lead 14
If there is no bend in the left-right direction in A-D, the intervals between the pulses generated by the beam interruption from the sink detection laser light source are equal (Fig. 7 (b)), and each lead A-D has no bend in the left-right direction. It can be seen that there is no bend.

On the other hand, if the lead 14B has a rightward bend, as shown in FIG. 8(b), the first and second leads from the left (first)
The distance between the second and third pulses is wide, and the distance between the second and third pulses is narrow, resulting in uneven intervals. This shows that there is a lead that curves in the left and right direction.

Note that the present invention can also be applied to a bending type IC lead such as a DIP type.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to scan a light beam relative to a lead array, and detect whether the lead is bent or not based on the presence or absence of a pulse generated when the lead blocks the laser beam and the pulse interval. . As a result, even if the lead position changes three-dimensionally, it is not subject to the limitations of depth of focus as in conventional detection, and is not affected by the lead surface condition, making it possible to improve detection accuracy. ．． Furthermore, since signal processing becomes simple, detection speed can be increased.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of an IC lead bend detection device according to an embodiment of the present invention, FIG. 2 is a plan view showing the relationship between the laser beam scanning line and the IC, and FIG. 3 is a side view of the RC. Figure 4 is the IC
A coordinate diagram showing the position of the tip due to the bending of the lead, Figures 5 to 8 are waveform diagrams showing the interruption of the laser beam detected by the light receiving element as a pulse count, and Figure 9 is a diagram showing the position of the tip of the conventional IC.
FIG. 2 is a perspective view of a lead bend detection device. IO...Laser light source, l1...Laser beam, 12
... Light receiving element, l3... IC, 14A-148...
・Lead, 15...rc path cage, 16A, 16B
, 16C... Straight line (relative scanning line of laser beam) Agent Patent attorney Tsuneaki Nagao Figure 2 Figure 4 Figure 5 Figure 7 Figure 1L4'' Figure 8

Claims (2)

[Claims] (1) A sinking detection light beam that relatively scans a straight line set inside the straight line connecting the tips of multiple IC leads arranged in a row when they are in normal shape, and a light beam set outside the straight line connecting the tips. The floating detection light beam relatively scans a straight line, and since the sinking detection light beam is not blocked by the IC lead, the downward bending of the IC lead can be detected, and the floating detection light beam can detect the downward bending of the IC lead. A method for detecting bending of an IC lead, characterized in that upward bending of the IC lead is detected by being interrupted by the IC lead. (2) The IC according to claim 1, wherein the relative scanning of the sunken detection light beam is performed at a constant speed, and the horizontal bending of the IC lead is detected based on the length of the pulse interval. Method for detecting lead bends.