JPH0454567A - Inspecting method for external appearance of electronic parts - Google Patents

Abstract

PURPOSE:To attain the accurate investigation of the external appearance of the electronic parts despite the variance of the appearance gradation by obtaining the density distribution of the appearance image of a photographed electronic parts and deciding an optimum quantization level from the density distribution for decision of investigation. CONSTITUTION:The external appearance of the mold resin of an IC 1 is picked up by an image pickup camera 3, and the position of the IC 1 is detected by a slice table memory 11 based on the image pickup data and a fixed slice level. Then the gradation distribution is detected by a mold gradation detecting part 17 based on the position of the IC 1. An investigation deciding optimum quantization level is decided from the gradation distribution characteristic. Based on this quantization level, a comparator 13 decides the investigation for decision of the appearance quality of the IC 1. Thus the external appearance of an electronic parts can be accurately checked despite the variance of the appearance gradation.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Field of Application) The present invention relates to an electronic component appearance inspection method for inspecting the appearance of an electronic component such as a DIP type IC.

(Prior art) The exterior of a DIP type IC is made of molded resin, but in order to ship the IC as a product, in addition to the function and performance of the internal electronic circuit, the exterior is also important as a product. is an element. This IC external appearance inspection is performed by checking the external appearance of the IC.
The D image sensor captures an image, quantizes the captured image data, and then compares it with a predetermined quantization level.

More specifically, in this comparison, the IC portion is detected from the captured image by comparing the captured image data with a fixed quantization level for position detection, and then the image data corresponding to the detected IC portion is It is compared with a fixed quantization level for pass/fail judgment.

(Problems to be Solved by the Invention) Conventional visual inspection is performed by comparing the image data of an IC captured by an image sensor with a fixed quantization level for position detection and a fixed quantization level for quality determination. Since there are variations in shading in the mold resin of the external appearance, comparison using a fixed quantization level like this makes it difficult to detect even if there are scratches on the external appearance of the IC. The problem is that it cannot be done.

The present invention has been made in view of the above, and an object of the present invention is to provide a method for inspecting the appearance of electronic components that can be accurately inspected even if there are variations in shading in the appearance.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, the electronic component appearance inspection method of the present invention images the appearance of the electronic component, determines the density distribution of the captured image, and performs inspection based on this density distribution. The purpose of this paper is to determine the optimal quantization level for judgment.

(Operation) In the electronic component appearance inspection method of the present invention, the density distribution of a captured image of the appearance of the electronic component is obtained, and the optimum quantization level for inspection determination is determined from this density distribution.

(Example) Hereinafter, the present invention will be explained in detail using the drawings.

FIG. 1 is a configuration diagram of an inspection apparatus for carrying out an external appearance inspection method for electronic components according to an embodiment of the present invention. The device shown in the figure is used to transfer IC1 during inspection process, etc. to an IC mold C.
A CD imaging camera 3 captures an image, and a photoelectric conversion circuit 5 converts the captured ICI image signal into an electrical signal, which is then converted to an A/D converter.
A converter 7 converts the data into digital image data and stores it in a molded multi-valued image memory 9.

The image data stored in the multilevel image memory 9 is compared with the fixed slice level for mold position detection from the slice table memory 11 to form a quantized image, and this quantized image is stored in the quantization memory 15. , whereby the position of the ICI is detected.

On the other hand, the image data stored in the multilevel image memory 9 is supplied to the pattern processor unit 19 via the mold density detection section 17, and is quantized corresponding to the position of the ICI stored in the quantization memory 15. The image information is supplied to the pattern processor unit 19, and the pattern processor unit 19 detects the density distribution of the ICI.

The ICI density distribution thus obtained is shown in FIG. The shading distribution shown in the same figure is plotted as a histogram with concentration on the horizontal axis, but the maximum value of this shading distribution is divided into several peaks as shown in the enlarged view of the same figure. Therefore, the center of the position that is several percent lower than the maximum value (MAX) is set as the mold density center value. Then, a density position biased in the density direction by a certain constant value from this density center value is determined as the optimum quantization level for inspection. Note that this optimum quantization level is set at a point where the gradation distribution curve shown in the figure is divided at a ratio of 7:3, that is, a ratio of 7 on the left side and 3 on the right side. and,
A comparator 13 performs a comparison based on this optimum quantization level for inspection, creates a quantization memory image, and performs inspection determination.

In this way, by compensating for variations in the shade of the mold resin using the optimal quantization level determined from the shade distribution of the mold resin that makes up the external appearance of the IC1, it is possible to perform the external appearance inspection of the IC accurately and with high reliability. It is.

FIG. 3 is a flowchart showing the operation of the appearance inspection device shown in FIG. Step 120), then step 1 to detect the density distribution.
30), determine the optimum quantization level for inspection judgment from this density distribution characteristic (step 140), perform inspection judgment based on this optimum quantization level (step 150), and thereby judge whether the appearance of the ICI is good or bad. There is.

FIG. 4 is a perspective view showing the overall appearance of the visual inspection apparatus shown in FIG. 1. The visual inspection apparatus shown in the figure is provided with a plurality of cameras constituting the imaging camera 3 at the top.

Although the above embodiments are described as inspecting the appearance of an IC, the appearance inspection method of the present invention is not limited to this, and can be applied to many electronic components including ICs. It is.

〔Effect of the invention〕

As explained above, according to the present invention, the density distribution of the captured image of the external appearance of an electronic component is obtained, and the optimum quantization level for inspection judgment is determined from this density distribution. By conducting a visual inspection by
Even if there are variations in shading in the appearance, the appearance can be accurately inspected without being affected by this.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an external appearance inspection apparatus that implements an electronic component appearance inspection method according to an embodiment of the present invention, FIG. 2 is a histogram showing the shading distribution of the external appearance of an IC, and FIG. FIG. 4 is a flowchart showing the operation of the appearance inspection apparatus, and FIG. 4 is a perspective view showing the overall structure of the appearance inspection apparatus of FIG. 1...IC. 3... Imaging camera, 9... Multivalued image memory, 11... Slice table memory, 13... Comparator, 15... Quantization memory, 17... Mold density detection section, 19. ...Pattern processor unit.

Claims (2)

[Claims] (1) A method for inspecting the appearance of an electronic component, which is characterized in that the external appearance of the electronic component is imaged, the density distribution of the imaged image is determined, and the optimum quantization level for inspection determination is determined from this density distribution. (2) Claim (1) characterized in that the optimum quantization level is a level on a brighter tail side of the density distribution.
) Appearance inspection method for electronic components as described.