JPS61233304A - Inspecting method for electronic parts lead - Google Patents

Abstract

PURPOSE:To discriminate whether an electronic parts lead is indefectible or not in accordance with the output waveform of an optical sensor which is provided for detecting the deformation of the lead by the reflection of light. CONSTITUTION:An optical sensor 2 is so set that the light from this sensor 2 is projected at about right angles to front ends of leads L1-L5 in one side of an LSI flat package 1, and the sensor 2 is moved to a position 2' in parallel in the direction of an arrow 7 from the lead L1 toward the lead L4. The voltage indicated on a discriminator is a maximum value V3 when the optical sensor 2 is placed just above the lead L3, and it is a minimum value V4 when the optical sensor 2 is placed just above the lead L4. Consequently, the distance between the lead L3 and the optical sensor 2 is shortest, and that between the lead L4 and the optical sensor 2 is longest. This LSI flat package is discriminated as defective goods if Vmax-Vmin>Va is true when the voltage determined by the allowable value of the variation of height of leads is denoted as Va, and it is discriminated as indefectible goods with respect to deformation of height of leads if Vmax-Vmin<=Va. Thus, it is discriminated surely whether electronic parts leads are indefectible or not.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention inspects the deformation of the leads of electronic components such as LSI flat packages before mounting them on a printed circuit board, and identifies those whose deformation exceeds the allowable value and which are non-defective. This invention relates to an electronic component lead inspection method used for identification methods, etc.

Conventional Technology When mounting an LSI flat package as shown in Figure 1 at a predetermined position on a printed circuit board, conventionally the deformation of the leads of the LSI flat package was visually sorted into good and defective products, or using a computer. Pass/fail was determined using advanced recognition technology.

Problems to be Solved by the Invention However, with the conventional visual inspection method, it is difficult to accurately distinguish between good and defective products based on the allowable value of deformation. The work of making the distinction forced the examiner to become extremely fatigued.

In addition, the method of shape recognition using a computer requires a lot of time and money for software development, and has the problem that the inspection device becomes expensive.

Means for Solving the Problems In order to achieve the above object, the present invention provides an optical sensor that detects the deformation of the lead of an electronic component by reflecting light, and an optical sensor that detects the deformation of the lead of an electronic component based on the output of the optical sensor, based on the allowable limit value of the deformation. , a discriminator is installed to distinguish between good and defective products, and vague visual inspection is not required (
Therefore, according to the present invention, an optical sensor is used in place of the human eye, and a discriminator is used in place of the human brain to automatically determine whether the quality is good or bad. This has the effect of making it possible to discriminate.

Embodiment FIGS. 1 and 2 show an embodiment of the present invention. 1 is an LSi flat package, and 2 is an optical sensor that emits projected light 3 and receives projected light 4. Here, optical sensor 2
The device can detect changes in the strength of the reflected light 4 depending on the distance between the optical sensor 2 and the lead L that reflects the projected light. 6 is a discriminator with optical sensor 2 and cable 5
The strength of the reflected light is received as a change in voltage through photoelectric conversion, and the quality is determined based on the magnitude of the change.

Now, as shown in FIG. 2, the optical sensor 2 is set so that the tips of the lead group L-L on one side of the LSi flat package 1 are projected at a nearly right angle, and the arrow is directed from the lead L to the lead L. Translate it parallelly as shown in 7 and move it to the 2゛ position. At that time, the voltage displayed on the discriminator 6 is as shown in FIG. 3, for example.

In other words, the voltage when the optical sensor is directly above lead L is V
, when directly above L is below V, similarly, 12
When it is directly above jlL5, it becomes V. In this example, v3 is the maximum value and ■ is the minimum value, thus indicating that the distance between the lead L3 and the optical sensor 2 is the shortest, and the distance between the lead L3 and the optical sensor is the longest. Here, if the voltage determined from the allowable value of variation in the height of the lead L is V, then V - V, >
If V, then this LSi flat package is a defective product.
If V-V, ≦V, the product is considered to be good in terms of lead height deformation.

On the other hand, the optical sensor 2 is moved at a constant speed in the direction of the arrow shown in FIG.
1x, x are leads L and L, L and LlL, respectively.
Tori, L (!: L's Sen + 22 3
3 4 4 5riClSC2
, C3, and C4. Therefore, time 1X in Figure 3
l and 1 are a and a in FIG. 2, respectively.

+23 12
Corresponds to a. Therefore, the horizontal deformation of the lead is 1
Xl It can be determined by the size of Xl.

In addition, s
It represents the time equivalent to a distance of 445 degrees.

4 and 5 show examples of waveforms tested in the same manner. If the peaks of the waveform are flat and the valleys are sharp, as shown in Figure 4, 1. 1. 1
If the peaks of the waveform are sharp and the valleys are flat, as shown in FIG. 5+23, it is better to judge the quality by S 1S XS XS. The waveform shown in FIGS. 3, 4, and 5 is determined by the type of optical sensor and the lead dimensions of the LSi flat package. In the above embodiment, the optical sensor receives and detects the reflected light that is almost parallel to the reflected light, but the same function can be achieved with an optical sensor that receives reflected light that is diffusely reflected and is not parallel to the reflected light. Of course.

Effects of the Invention As is clear from the above embodiments, the present invention includes an optical sensor that detects changes in reflected light due to distance, and a discriminator that converts the light into electricity and determines whether it is good or bad based on the maximum value of its intensity. Because of this, the equipment configuration is simple and the price is low, and it is possible to reliably distinguish between good and bad without the problems of uncertainty and worker fatigue that are associated with visually distinguishing between good and bad. .

[Brief explanation of drawings]

Fig. 1 is a configuration diagram of an embodiment of the present invention, Fig. 2 is a detailed diagram of the embodiment, Figs. 3 to 5 are signal waveform diagrams of the embodiment, and Fig. 6 is a general integrated circuit flat diagram. FIG. 7 is a perspective view of the package, FIG. 7 is a top view of the general example, and FIG. 8 is a front view of the general example. 1... Integrated circuit, 2... Optical sensor, 3
...Projected light, 4...Reflected light, 5...
... Cable, 6... Discriminator. Name of agent: Patent attorney Toshio Nakao and one other person Figure 1
7. Collecting circuit No. 3rM No. 47 Fig. 5

Claims (1)

[Claims] An optical sensor that projects light onto the lead of an electronic component and detects the displacement of the lead using the reflected light is moved so that light is projected onto multiple leads sequentially, and the waveform output from the optical sensor detects the displacement of the electronic component. An electronic component lead inspection method that determines whether the lead shape is good or bad.