JPS62191705A - Apparatus for inspecting appearance of electric/ electronic parts - Google Patents

Abstract

PURPOSE:To enhance inspection accuracy and to make it possible to inspect the appearance of a surface state, by providing a light source control circuit, a TV signal processing circuit, an A/D converter circuit, a correction/memory circuit, a binarization circuit, a majority circuit, a counter circuit and a control circuit, etc. CONSTITUTION:A light source control circuit 20 controls a light source 1 to preliminarily irradiate blank paper and a model article 2 to be inspected with light 3 and a correction/ memory circuit 23 stores the light receiving characteristic of the light of a TV camera 4 at the time of the imaging of the blank paper and the characteristic of light irregularity reflected from the model article 2 to be inspected at the time of the irradiation of the model article 2 to be inspected and determines reference brightness to store the same. On and after, the signal of the brightness transmitted through an A/D converter circuit 22 is corrected on the basis of the reference brightness to be transmitted to a TV signal processing circuit 21 and a binarization circuit 24 binarizes this signal. A majority circuit 25 compares binarized data of the circuit 24 corresponding to an inspection place memory 27, for example, A, B, C with the preliminarily stored reference brightness to form and store the binarized data. A counter circuit 31 applies counting processing to the signal transmitted from the circuit 25. A control circuit 26 controls each circuit and the whole of the system.

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to a visual inspection device for electrical/electronic components.

<Conventional technology> Conventionally, electrical and electronic components, especially flat plated parts such as ICJ-de frames, are inspected for spots, gloss, scratches, shape, etc. through visual appearance inspection in the finishing inspection process. Although efforts are being made to improve the quality of products, many of these visual inspections are performed visually, which results in individual differences, which are exacerbated by the degree of fatigue. Therefore, as an external appearance inspection device for electrical/electronic parts that mechanizes this visual inspection, for example, the one shown in Figure 3 is known [--Refer to "Labor Saving and Automation" published by Ohmsha, July 1985 issue. ]. This visual inspection device irradiates light 3 from light #1 onto an inspected object 2 such as electrical or electronic parts, and uses the reflection of this light 3 to visualize the inspected object 2, vertically, vertically, etc.
TV camera 4 as horizontal, subdivided dot-based signals
The signal is transmitted to the video monitor 5 in its original state, that is, in a state of different brightness such as bright or dark. The signal transmitted to the video monitor 5 is compared with a reference brightness set by a computer 6 connected to the video monitor 5, and converted into black or white binary data. That is, the signal reflected by the object 2 to be inspected and transmitted to the video monitor 5 and computer 6 through the television camera 4 will have a blackish tinge if the surface of the object 2 to be inspected has scratches 7 or stains. A signal with low brightness that has been removed, and a signal with high brightness that is whitish in normal conditions with no scratches, are transmitted to the computer 6. Therefore, this signal is binarized so that only black or white remains and is displayed on the video monitor. 5 as a video 8 signal. In this way, when there are scratches 7 or stains on the surface of the object 2 to be inspected, the normal areas appear white on the video monitor 5.
An image 8 of the black part with the scratch 7 is expressed and can be visually confirmed by the shading on the video monitor 5.

Furthermore, the computer 6 counts the number of dots remaining black in the image 8, that is, the scratches 7, and if the size of the dots exceeds a set value, this is determined to be a defect. .

<Problems with the prior art> However, in such a conventional visual inspection device, the light 3 of different brightness (bright or dark) reflected by the inspected object 2 is directly transmitted as a signal, and the brightness and computer Since the brightness was compared with a standard brightness set to 6 and converted into a binary value, the test accuracy could be poor depending on the brightness reception characteristics of the television camera 4 and the shape and condition of the object 2 to be inspected. That is, depending on the television camera 4, the light may be received in a state where the overall brightness is brighter or darker than the actual brightness, or the light may be received in a partially bright or dark state with "unevenness"; If the test object 2 is made by "punching" such as the lead frame (c), there will be unevenness at the edge of the lead part (not shown) of the lead frame due to the punching, and this unevenness will cause the light source 1 to emit light. If there is an angle of incidence of the light 3 and a reflection angle of the light 3 reflected from the object 2 to be inspected, the television camera 4
The light 3 that differs from the actual reflected light may be input, causing the entire area to be illuminated, or the brightness to be different between the surrounding area and the center area (uneven brightness, uneven light). Therefore, there are many uncertainties in the signal itself transmitted to the video monitor 5 through the television camera 4, and therefore, the data obtained by converting this signal into binary data also has many uncertainties.
The accuracy of the image on the video monitor 5 and the count of scratches 7 based on this binarized data becomes uncertain, and the accuracy of the overall visual inspection deteriorates.

This invention was developed in view of the above points, and the signal transmitted to the video monitor 5 through the television camera 4 is adjusted to the light receiving characteristics of the television camera 4 and the light unevenness of the object 2 to be inspected. An appearance that improves inspection accuracy even for the inspected object 2 with uneven light by correcting it according to the unevenness of light using the standard value of the brightness of the inspected object 2 and converting the corrected signal into a binary value. The purpose is to provide inspection equipment.

<Means for Solving the Problems> The structure of the present invention for achieving the above object will be explained using FIGS. 1 and 2, which correspond to embodiments. The visual inspection apparatus of the present invention mainly includes a light source control circuit 20, a television camera 4, a television signal processing circuit 21, an analog-to-digital conversion circuit 22 (hereinafter simply referred to as an AD conversion circuit), and a correction/storage circuit 23.2. Value conversion circuit 24, majority decision circuit 25,
It is comprised of a counting circuit 31, a control circuit 26, and an inspection location memory 27 that stores an arbitrary preset inspection location.

The light source control circuit 20 is a circuit for controlling the light source 1 so as to uniformly irradiate the inspection object 2 with the light 3.

The television signal processing circuit 21 is a circuit that processes a signal of the brightness of the reflected light 3 from the object to be inspected 2 transmitted via the television camera 4 .

The AD conversion circuit 22 is a circuit that converts the signal from the television camera 4 transmitted via the television signal processing circuit 21 from analog to digital.

The correction/storage circuit 23 stores a blank sheet and a model inspected object in advance.
(not shown) are irradiated with the light 3 from the light source control circuit 20, and the light 3 is visualized by the television camera 4. When creating a blank image, the light receiving characteristics of the light 3 of the television camera 4 and the model When the object to be inspected is irradiated, the characteristics of the light unevenness reflected from the model object to be inspected are memorized and corrected based on the characteristics of the model object to be inspected and the light receiving characteristics of the light 3 from the television camera 4 to set the standard brightness in advance. Determine and memorize. This is a circuit for correcting a luminance signal transmitted thereafter via the A-D conversion circuit 22 using the reference luminance, and transmitting the corrected luminance signal to the television signal processing circuit 21.

The binarization circuit 24 is a circuit that binarizes a plurality of corrected luminance signals transmitted from the television signal processing circuit 21 into black or white, and is a circuit that binarizes a plurality of corrected luminance signals transmitted from the television signal processing circuit 21 into black or white. In the example, W.

(24W, 24x,
24 V, 24 z).

The majority circuit 25 compares each of the binarized data A, B, and C of the binarization circuits 24w, 24x, 24y, and 24z corresponding to the inspection location memory 27 with a pre-stored reference brightness. This is a circuit that creates and stores binarized data based on a majority vote.

The counting circuit 31 receives a signal transmitted from the majority circuit 25,
In other words, it is a circuit that counts and processes binary data that indicates pass/fail for each dot on the screen.
, B, C [31a, 3 l b,
31 c) Provided.

The control circuit 26 is a circuit that controls each of the circuits and the entire system.

<For production> This invention will be explained in detail.

Setting the reference brightness: First, a blank sheet of paper is irradiated with light 3 and the reflected light is photographed with a television camera 4. When creating a blank image, the brightness characteristics of the television camera 4, that is, the state of uneven light such that light is received with partially different brightness, is stored in the correction/storage circuit 23.

Next, light 3 is irradiated onto the model test object, which is intact and has accurate gloss, plating areas, etc., and the characteristics of the reflected light are determined, i.e., which parts of the model test object are bright or dark. The state corresponding to the reflected light is memorized.

Then, correction is made based on the characteristics of the reflected light of the model object to be inspected and the characteristics of the light unevenness of the television camera 4, and a reference brightness is determined in advance and stored in the correction/storage circuit 23.

Inspection of the object 2 to be inspected; irradiates the object 2 sent after setting the reference brightness with light 3, converts the reflected light from the object 2 into a signal, and sends the signal to the television signal processing circuit 21-A-D conversion circuit. 22-Correction/memory circuit 23
Here, the signal is corrected by the reference brightness, and the signal of the object 2 to be inspected, which is in a state of uneven light, and the light reception characteristics of the television camera 4 are changed to a TV signal in a state without uneven light. It will be transmitted to the processing circuit 21.

Binarization of signal; The signal transmitted from the television signal processing circuit 21 is binarized into black or white in the binarization circuit 24. The signals to be binarized here are a plurality of signals whose light unevenness has been corrected.
- Judgment of quality of the inspected object 2; each location W, X stored in the inspection location memory 27.

Binarization circuits 24w, 24x, 24y, corresponding to Y and Z,
Binarized data A, B, and C are compared every 24z in a majority decision circuit 25, and binarized data is created and stored by majority decision. Since the binarized data A, B, and C created here are signals with light unevenness corrected, appropriate binarization can be performed even if the state of reflection of the light 3 on the inspected object 2 is not uniform. It is what it is.

Furthermore, by setting the inspection location memory 27 to any position with different brightness, areas that are shiny and difficult to perform a normal inspection or areas that cannot be judged due to different brightness are corrected, and the equalized signal becomes a binary value. Since it is possible to inspect the "surface" condition easily. Then, the number of defective locations compared by the majority circuit 25 is counted for each inspection location memory 27 by the corresponding counting circuits 31a, 31b, and 31c, and finally, the number of defective locations is greater than the reference value. If it exceeds the value, the object to be inspected 2 is determined to be defective.

<Embodiment> An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. Incidentally, parts that are the same as or common to the conventional ones are indicated by the same reference numerals in the drawings, and redundant explanations will be omitted. This inspection device mainly includes a light source control circuit 20, a television camera 4
, a television signal processing circuit 21, an analog-digital conversion circuit 22 (hereinafter simply referred to as an A-D conversion circuit), a correction/storage circuit 23, a binarization circuit 24, a majority circuit 25, a counting circuit 31, a control circuit 26, and a It is composed of an inspection location memory 27 that stores arbitrarily set inspection locations.

The light source control circuit 20 is a circuit for controlling the light source 1 so as to uniformly irradiate the inspection object 2 with the light 3.

The television signal processing circuit 21 converts the state of the reflected light 3 from the inspected object 2 transmitted via the television camera 4, that is, the state of different brightness such as bright or dark, into a signal and performs A-D conversion. The signal is transmitted to the circuit 22. or,
A signal from a correction/storage circuit 23, which will be described later, is converted to a binarization circuit 2.
This circuit also has the role of transmitting information to 4.

The AD conversion circuit 22 is a circuit for AD converting the signal from the television camera 4 transmitted via the television signal processing circuit 21 and transmitting the converted signal to the connected correction/storage circuit 23.

The correction/storage circuit 23 stores a blank sheet and a model inspected object in advance.
(not shown) are irradiated with the light 3 from the light source control circuit 20, and the light 3 is visualized by the television camera 4. When creating a blank image, the light receiving characteristics of the light 3 of the television camera 4 and the model When the object to be inspected is irradiated, the characteristics of the light unevenness reflected from the model object to be inspected are memorized and corrected based on the characteristics of the model object to be inspected and the light receiving characteristics of the light 3 from the television camera 4 to set the standard brightness in advance. Determine and memorize. This is a circuit for correcting a luminance signal transmitted thereafter via the A-D conversion circuit 22 using the reference luminance, and transmitting the corrected luminance signal to the television signal processing circuit 21. Specifically, first, light 3 is irradiated onto a blank sheet of paper, and the reflected light is visualized using a television camera 4 to create a close-up image. The state of light unevenness, such as the light being received differently, is stored in the correction/storage circuit 23, and then the light 3 is irradiated onto the model test object, which is intact and has accurate gloss, plating areas, etc., and the light is reflected. The characteristics of the light, that is, which parts of the model to be inspected are bright or dark (that is, the state depending on the reflected light of uneven light) are memorized.The characteristics of the reflected light of this model to be inspected and the television camera 4 The standard brightness is determined in advance and stored in the correction/storage circuit 23, and the test object 2 is the edge of the lead part (not shown) of the IC lead frame. Since the width size is a number 1 or a comma number, as in the case of the lead part, even if the entire end part is illuminated due to the reflection of the light 3 irradiated into the gap at the tip of the reed part, the peripheral part and the center part are even different. Even if the brightness is different, the brightness signal subsequently transmitted to the correction/storage circuit 23 is corrected and binarized using the reference brightness. The signal No. 2 is transmitted to the television signal processing circuit 21 in a state with no unevenness of light due to the correction described above, and the provision of this correction/storage circuit 23 is one of the major features of the present invention. Note that this correction/storage circuit 23 performs the correction multiple times for one location [in the illustrated example, A, B, and C
3 times] and the signal is repeatedly transmitted to the binarization circuit 24 via the television signal processing circuit 21. The correction/storage circuit 23 is also equipped with a filter (not shown) that corrects noise in the signal from the television camera 4 transmitted via the television signal processing circuit 21.

The binarization circuit 24 is a circuit that binarizes the corrected luminance signal transmitted from the television signal processing circuit 21 into black or white, and the signal to be binarized here has light unevenness corrected. For example, even if the entire portion is illuminated, appropriate binarization can be performed. Moreover, the binarization circuit 24 is provided [24w, 24x, 24y, 24z] corresponding to the arbitrarily set inspection location memory 27 [in the illustrated example, four locations W, X, Y, and Z]. be.

The majority decision circuit 25 compares the respective plurality of binarized data A, B, and C of the binarized circuits 24W, 24x, 24y, and 24z corresponding to the inspection location memory 27, and determines the binarized data by majority decision. This is the circuit to create.

The counting circuit 31 receives a signal transmitted from the majority circuit 25,
In other words, it is a circuit that counts and processes binary data that indicates pass/fail for each dot on the screen.
, B, C [31a, 3 l b,
31C) is provided, the number of defective locations is counted, and if the number of defective locations exceeds the reference value, the object to be inspected 2 is determined to be defective.

The control circuit 26 is a circuit that controls each of the circuits and the entire system.

In addition, 28 is a holder that sends out the object 2 to be inspected at predetermined intervals;
Reference numeral 29 represents a holder for inspected non-defective products, and 30 represents a holder for inspected defective products, and the control circuit 26 also controls the delivery from the holder 28 or the distribution of the inspected objects 2 to the respective holders 29 and 30 after the quality determination. It is something to do.

Next, the usage condition of the visual inspection device will be explained.

Setting the reference brightness; Checking the characteristics of the television camera 4; First, the light 3 is irradiated onto a blank sheet of paper, the reflected light is photographed by the television camera 4, and when this blank sheet is visualized, the characteristics of the brightness of the television camera 4, that is, partially The state of light unevenness such that light is received with different brightnesses is stored in the correction/storage circuit 23.

Check for light unevenness on the model test object; Next, light 3 is irradiated on the model test object that is intact and has accurate gloss, plating areas, etc., and the characteristics of the reflected light are checked. The state corresponding to the reflected light of uneven light is memorized, such as which part becomes brighter or darker.

Then, correction is made based on the characteristics of the reflected light of the model object to be inspected and the characteristics of the light unevenness of the television camera 4, and a reference brightness is determined in advance and stored in the correction/storage circuit 23. In this way, the reference brightness that has been corrected for the light unevenness, that is, the state where the lead part of the IC lead frame shines, the state where the center part is a little darker than the surrounding part, and the light receiving characteristics of the television camera 4 is corrected. This value will be stored as the reference value of the brightness of the inspection object 2.

Inspection of the inspected object 2; The inspected object 2 sent out from the holder 27 at predetermined intervals is irradiated with the light 3, and the reflected light from the inspected object 2 is converted into a signal to be sent to the television signal processing circuit 21-A-D conversion circuit 22. - The signal is transmitted to the correction/storage circuit 23, where the signal is corrected by the reference luminance, and the signal of the object 2 to be inspected, which is in a state of light unevenness, is changed to the TV signal processing circuit 23 in a state where there is no light unevenness due to the correction. It will be transmitted to

Binarization of signal; The signal transmitted from the television signal processing circuit 21 is binarized into black or white in the binarization circuit 24. The signals to be binarized here are A and B with light unevenness corrected.

This is the signal of C three times.

Judgment of quality of inspected object 2; Each location W and X stored in the inspection location memory 27.

Binarization circuits 24w, 24x, 24 corresponding to y and z
Binarized data A, B, C for every y, 24z is passed to the majority decision circuit 2.
5 and create binarized data by majority vote. Then, the counting circuits 31a, 31b, and 31c respectively count and process the binarized data for each dot transmitted from the majority circuit 25, and finally, if the defective location exceeds the reference value, the target This indicates that the object to be inspected 2 is defective.

Since the binarized data A, B, and C used for this quality judgment are signals with light unevenness corrected, appropriate binarization is possible even for parts that are completely illuminated, such as the end of a lead. This is something that can be done.

Moreover, if the inspection location memory 27 is set to an arbitrary position that has a different brightness from, for example, the edge of the island, the periphery and center of the lead, it is possible to separate Areas that could not be judged due to differences in brightness can be binarized using a uniform signal, so even planar island areas can be inspected easily and with high precision. This means that defects in overall shape and misalignment of plating relative to the part to be plated can also be inspected. In addition, since the lead part in the illuminated state is corrected and the signal in the non-lit state can be binarized, it is also possible to inspect cases where the lead part is bent in the direction perpendicular to the light irradiation. .

Further, the counting circuit 31 performs a counting process to count the number of defective locations, and the binary data of the multiple locations are treated as if they were one inspected object 2 by majority vote, and finally the defective locations are counted. If the value exceeds the reference value, the object to be inspected 2 is determined to be defective, and the object to be inspected 2 is distributed to the holder 30 by known means.

<Effects> Since the appearance inspection apparatus for electric/electronic parts according to the present invention has the content as described above, even if a signal with uneven light with different brightness is transmitted from the object to be inspected, the correction/memory circuit can It is corrected multiple times using the reference brightness stored in , and is transmitted to the binarization circuit without unevenness in bright or dark areas, allowing for proper binarization.
Even if any part of the object to be inspected is inspected, a signal corrected by the reference brightness can be extracted, making it possible to inspect the appearance of the surface. Since it is treated like an object, accuracy is improved, and since it is now possible to visually inspect the surface condition, it has the excellent effect of being able to inspect for defects in the overall shape, misalignment of plating, etc.

[Brief explanation of drawings]

FIG. 1 is an overall schematic perspective view of an appearance inspection apparatus for electric/electronic components according to the present invention, FIG. 2 is a functional block explanatory diagram showing the configuration of the present invention,
FIG. 3 is a functional block explanatory diagram showing a conventional example. 1- Light source 2- Object to be inspected (electrical/electronic parts) 3- Light 4- Television camera 5-/Video monitor 6- Computer 7... Scratch 8- Image 20-/ Light source control circuit 21- Television signal processing circuit 22 - Analog-digital conversion circuit 23 - Correction/memory circuit 24 - Binarization circuit 25 - Majority circuit 26 - Control circuit 27 - Inspection location memory

Claims (1)

[Scope of Claims] A light source control circuit that controls a light source to uniformly irradiate light onto an object to be inspected such as electrical/electronic parts, and a television camera that images and photographs the light irradiated from the object to be inspected. , a television signal processing circuit that processes the light brightness signal from the television camera; an analog-to-digital conversion circuit that converts the signal from the television signal processing circuit from analog to digital; When photographing a blank sheet, the light receiving characteristics of the TV camera are stored, and when the model object is irradiated with light, the characteristics of the light reflected from the model object are stored. The reference brightness is determined and stored in advance by correcting it based on the light characteristics of the model test object and the light receiving characteristics of the television camera, and thereafter the light signal transmitted via the analog-to-digital conversion circuit is corrected using the reference brightness. a correction/storage circuit that transmits the signals to the television signal processing circuit; and a correction/storage circuit that binarizes and stores the plurality of corrected luminance signals transmitted from the television signal processing circuit and a pre-stored reference luminance, and The binarized data of each of the binarized circuits provided corresponding to the inspection location memory that stores the inspected location memory and the binarized data of the binarized circuits corresponding to the inspection location memory are compared, and the binary data is determined by a majority vote. An electrical/electronic device comprising: a majority circuit that creates digitized data; a counting circuit that counts the data processed by the majority circuit for each inspection location memory; and a control circuit that controls the entire system including each of the circuits. Appearance inspection equipment for parts.