JPS61294304A - Lead bend detector - Google Patents

Abstract

PURPOSE:To discriminate intervals of center positions of pins with a high precision independently of the number of IC pins by detecting leads of a passing IC for every two pins adjacent to each other. CONSTITUTION:An IC 1 is slid in the direction of an arrow DIR, and optical fiber arrays FAR and FAL are attached in such positions at right angles to the lengthwise direction of leads that parts near front end parts of lead end faces of the IC 1 can be detected. When the lead of the IC 1 traverses the array FAR in accordance with sliding of the IC 1, the light incident on optical fibers corresponding to the lead passing part is intercepted, and a detecting part DT is black in a part corresponding to this interception. Passing of the lead is monitored in an optional position PM of the detecting part to obtain the interval between two pins adjacent to each other by a discriminating part 2.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an apparatus for inspecting the appearance of integrated circuit (hereinafter abbreviated as IC) packages, particularly for inspecting lateral concurrence of leads.

[Conventional technology]

Conventionally, this type of detection device uses a camera that uses a line sensor or an area sensor that temporarily stops the ICI moving in the direction of the arrow DIR as shown in Fig. 4 and is provided on the side of the lead 1α. CA captured the entire image of the lead lcL, and image processing was used to detect horizontal white spots on the lead.

[Problem that the invention seeks to solve]

The conventional detection device described above uses a camera to effectively photograph all leads at once, so when the number of pins on an IC is small,
The lead corresponding to a pin can be taken larger, and when the number of IC pins is large, the lead corresponding to one bin can be taken smaller.

This means that as the number of pins on an IC increases, the number of pixels that can fit into one bin decreases, resulting in poor accuracy and, in the worst case, impossibility of measurement. [mI] This method has the disadvantage of not being able to detect multi-pin ICs.

The present invention provides a lead bending detection device that processes and inspects passing IC leads for two adjacent bins at a time.

[Means for Solving the Problems] The present invention provides an optical fiber array having a structure in which N optical fibers are arranged in a straight line at equal intervals (N is an integer) in the longitudinal direction of the leads of an IC package. A means for detecting the presence or absence of a lead using M arbitrary optical fibers (M is an integer of 1 or more) in an optical fiber array in a device arranged perpendicular to the optical fiber array;
For each optical fiber in the fiber array, we use a means to detect the presence or absence of light, and from the output obtained from the presence or absence of light from each optical fiber, we calculate the center position of each adjacent lead. A lead bending detection device is characterized in that it has means for determining an interval between center positions.

〔Example〕 Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 3 shows an embodiment of an optical fiber array FA constructed by arranging one optical fiber A in a straight line at equal intervals. For light projection in this fiber array, either the commonly used transmission type or reflection type may be used.

Now, DIP (DUAL IN PA Genhiro GE) type IC
This will be explained by taking the lateral same bending as an example. Its appearance is shown in Figure 1.

The optical fiber arrays FAR and FAL are installed at right angles to the longitudinal direction of the IJ-C at a position where the optical fiber array C1 slides in the direction of the DIR and the vicinity of the tip of the side surface of the ICI lead can be detected.
Attach to the left and right. Also, this fiber array FAR,
FAL is assumed to be a transmission type fiber, and light source LT is assumed to be located inside the ICI as shown in FIG.

The operating principle of the present invention will be explained in this state.

The operation of the fiber array FAR on the right side of FIG. 1 will be explained. The plan view of FIG. 1 is shown in FIG. 2, and the detection section DT of the fiber array FAR is shown as white when light is incident from the outside in the drawing, and as black when the light is blocked. When the IC is not in the fiber array FAR section, all light emitted from the light source LT is sent to the fiber array FA.
It enters the R section, and all of the detection sections DT are white. However, when the ICI slides in the direction of the DIR and the ICI lead crosses the fiber array FAR section, the incident light to the optical fiber corresponding to the lead passage section is blocked and the corresponding detection section DT becomes black.

Therefore, paying attention to the arbitrary position of the detection part (PM in Fig. 2),
Its position shall be monitored. That is, the position PM
Monitor the lead as it passes.

In Fig. 2, when the ICI slides in the direction of DIR and the first lead PIR of the IC passes the monitor position PM, the detection part D
T is DT in Fig. 2, lead PlR and lead P2.
The portion blocked by R will be detected as black. That is, this data is latched at -H.

Based on the data obtained here, the determination unit 2 determines the lead PER.
Center position Pc0 of portion PBI corresponding to lead P2R
By finding the center position P(* of the part Pni corresponding to the distance PL), lead PIR and lead P2
The interval PL of R is found. Next, the lead interval between the lead P2R and the lead P3R is determined from the data of the detector DT when the second lead P2B passes the monitor position PM. Thereafter, all lead intervals can be found in the same manner.

The resolution in this case is determined by the distance between the optical fibers, which are arranged at equal intervals.

The same is true for the fiber array knee on the right side. Although the monitor position PM is set to one arbitrary point, two adjacent points or several points spaced apart may be selected to avoid the influence of noise.

In addition, in the example, the light projection was provided externally and the fiber array was used as a transmission type, but a reflection type fiber array was constructed using a single optical fiber as a reflection type, and the reflected light from the lead was detected by a detector and processed. You may also use the method of

〔Effect of the invention〕

As explained above, in the present invention, the leads of the passing IC are processed for two adjacent pins at a time.
Regardless of the number of C bins, there is no need to temporarily stop the IC, and by reducing the cross section of a single optical fiber, highly accurate measurement is possible, and processing is simple, reducing measurement time and reducing costs. There are effects that can be achieved at low cost.

[Brief explanation of the drawing]

FIG. 1 is a layout diagram of a fiber array used in an embodiment of the present invention, FIG. 2 is a top view of FIG. 1, FIG. 3 is a perspective view of a fiber array used in an embodiment of the present invention, and FIG. The figure is a front view of a conventional device. 1...IC, 2...judgment unit, F...one optical fiber, FA, FAR, FAL...optical fiber array, PIR, P2R. P3R, P4R, PNR...IC lead terminal, DT
, DTI...detection section patent applicant NEC Corporation ■ DIR Figure 2

Claims (1)

[Claims] (1) N pieces of one optical fiber (
(where N is an integer) In a device in which an optical fiber array with an array structure is arranged perpendicular to the longitudinal direction of the leads of an integrated circuit package, any M optical fibers in the optical fiber array (where M is an integer greater than or equal to 1) means for detecting the presence or absence of a lead, means for detecting the presence or absence of light for each optical fiber in the fiber array when a lead is detected, and a means for detecting the presence or absence of light for each optical fiber in the fiber array. What is claimed is: 1. A lead bending detection device comprising means for determining the center position of each of the twisted leads and determining the interval between the respective center positions.