JPH05249050A - Apparatus for inspecting external appearance of component - Google Patents

Abstract

PURPOSE:To inspect accurately the shape of the lateral side of a component. CONSTITUTION:A part except the fore end face 3 of a lead of IC 1 to be inspected is illuminated and only the fore end face 3 of the IC 1 is picked up as a dark image by a TV camera 6. As the result, an image not affected by the nonuniformity of the cut shape of the fore end face 3 of the IC 1 or a curve of the lead 2 is obtained and the lead 2 can be inspected accurately.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a visual inspection device for components, and more particularly to a device for visual inspection of leads, pitch, bending, floating, etc., of an IC package having lateral lead groups.

[0002]

2. Description of the Related Art In an IC package, it is required in terms of quality that the arrangement of lead groups on the side thereof be constant. Therefore, various types of devices for visually inspecting the appearance of the leads have been proposed.

7 and 8 conceptually show a conventional IC package (hereinafter simply referred to as IC) appearance inspection apparatus.

In the apparatus of FIG. 7, light is emitted from the light sources 24, 24 toward the tip cut surface 22 of the lead 21 to be inspected of the IC 20 mounted on the inspection stage 23. When this is imaged by the television camera 25, as shown in FIG. 9, each cut surface 22a, 22b, 22c captures an image that is a bright image due to reflected light, and an inspection is performed based on this image.

Further, in the apparatus of FIG. 8, the inspection stage 23
Light is emitted from the light source 24 toward the opposite side of the IC 21 mounted on the surface of the IC 20 from the lead 21 to be inspected. The inspection stage 23 'is made of a material that transmits light. Therefore, light is emitted from the lower surface of the IC 20 and the upper surface 23 'of the stage 23'.
While passing through the inspection stage 23 ′, the television camera 25 captures an image in which the entire lead 21 is a dark image as shown in FIG.

[0006]

By the way, each lead 2
The shapes of the tip cutting surfaces 22a, 22b, 22c of No. 1 have variations due to the non-uniformity of the cutting processing direction. 22 on the image (FIG. 9) captured by the device of FIG.
As shown by a, 22b, and 22c, it becomes noticeable, and it is difficult to accurately measure the pitch between the leads 21 based on this image. Although the apparatus of FIG. 8 does not have such a problem, since the entire lead 21 is obtained as a dark image (FIG. 10), when the lead 21 is largely bent as shown by an arrow A, the lead width on the image is large. It becomes larger than the actual lead width and leads 21
A measurement error such as a pitch between them will occur.

Further, when measuring the floating amount of the lead 21 or the like, it is necessary to set a reference line to be a reference.
In this case, in the apparatus shown in FIG. 8, since the inspection stage 23 ′ is made of a material that transmits light, the line indicating the upper end 23′a of the inspection stage 23 ′ to be the reference is clearly visible on the image. Don't come

For this reason, not the line showing the upper end of the side surface of the inspection stage 23 'on the image but the reference line mechanically fixed in advance is provided. However, during the actual inspection, the IC 20 moves up and down due to the influence of the vibration of the transfer device on the inspection stage 23 ', and the relative position between the fixedly set reference line and the lead 21 is displaced. .. Therefore, an accurate inspection may not be performed.

The present invention has been made in view of the above circumstances, and provides an apparatus capable of inspecting more accurately than before when inspecting a side surface of a component including a lead tip surface of an IC. That is the purpose.

[0010]

Therefore, according to the present invention,
The side surface of the component placed on the inspection table and the line indicating the upper end or the lower end of the inspection table are simultaneously imaged by the image pickup means, and the side surface shape of the component whose line is the reference line is used as a reference line. Accordingly, in a component appearance inspection device for inspecting a defect in the appearance of the component, each part of the component except the side face so that only the side face of the component imaged by the image capturing unit is obtained as a dark image by the image capturing unit. To illuminate.

[0011]

That is, according to such a configuration, each part of the component except the side face of the component to be inspected is illuminated, and only the side face of the component is obtained as a dark image by the image pickup means. As a result, if the side surface of the component is, for example, the tip end surface of the IC, an image that is not influenced by the uneven cutting shape or the bending of the lead is obtained, and the lead can be inspected accurately.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of a component visual inspection apparatus according to the present invention will be described below with reference to the drawings. In the embodiment, it is assumed that the appearance of the leads of the IC is inspected.

FIG. 1 conceptually shows the construction of the embodiment apparatus.

Flat package type IC 1 to be inspected
Are placed on the inspection stage 4. This inspection stage 4
Is made of a material such as acrylic or glass having a property of diffusing light, that is, transmitting incident light. I
C1 has a lead group including a plurality of leads 2 on its side surface, and the tip end surface 3 of the lead 2 is imaged by the television camera 4. Light sources 5a, 5a for illuminating each part of the IC1 excluding the tip surface 3 so that only the tip surface 3 of each part of the IC1 is obtained as a dark image by the camera 6.
b and 5c are arranged around the inspection stage 4. It should be noted that columns (not shown) that support the stage 4 are provided at the four corners of the lower surface of the inspection stage 4, and the lower light source 5 is provided.
The lower surface of the inspection stage 4 is irradiated with the light from b.

That is, the light for illumination is emitted from the light source 5b toward the upper side thereof and the lower surface of the inspection stage 4. Therefore, the irradiated light is incident on the lower surface of the inspection stage 4, passes through the inspection stage 4, and irradiates the lower surface of the lead 2. The light for illumination is emitted from the light source 5a under the lead 2
Is irradiated toward the upper surface of. On the other hand, illumination light is horizontally projected from the light source 5c toward the lead 2'on the side opposite to the lead 2 to be inspected. Here, the center of the optical axis of the light source 5c is set on the upper surface 4a of the inspection stage 4. The light illuminates the opposite side surface of the IC 1 and also passes through the stage 4. Furthermore, the lower surface of the lead 2 and the upper surface 4 of the stage 4
Pass between a. As a result, in the TV camera 6,
As shown in FIG. 3, only the lead tip surface 3 of the IC 1 becomes a dark image, and the image below the lower surface 4b of the inspection stage 4 becomes a dark image. The other part is a bright image due to the irradiated light.

The image data obtained by the television camera 6 is input to the image processing device 7. The television monitor 8 displays the captured image on the screen. As will be described later, the image processing device 7 includes a design dimension value relating to the IC 1 to be inspected,
A data input device 9 to which data for inspection such as an inspection reference value is input is connected. The image processing device 7
Based on the data input from the data input device 9, the process shown in FIG. 2 described later is performed to determine whether or not the IC1 is a non-defective product.

The processing executed by the image processing apparatus 7 will be described below with reference to the flowchart shown in FIG.

First, among the design dimension values of the IC 1 to be inspected,
Data indicating the pitch pt between the leads 2, the width ld of the leads 2, the thickness 1h of the leads 2, the number ln of the lead groups 2 ... Is input to the data input device 9. Further, the plate thickness h of the inspection stage 4 and the lead pitch allowable value dp, that is, the lead 2
Data about the tolerance of the pitch pt between them, the lead flatness allowable value dd, that is, the allowable value of the distance between the lead 2 and the inspection stage upper surface 4a is similarly input (step 101). Then, among the input data, ld and lh
Based on the above, the model image 14 of the lead 2 is generated as shown in FIG. It should be noted that the image of the lead 2 serving as a model may be cut out from the actually captured image and registered as a model image (step 10).
2).

Next, the image data of the IC 1 to be inspected is input from the television camera 6 (step 103). FIG. 3 illustrates an image captured by the camera 6, in which the X axis is set in the horizontal direction and the Y axis is set in the vertical direction. And 1
Lower surface 4 of inspection stage 4 as shown at 2a and 12b
A region including a line indicating b is cut out at two places on the left and right of the stage 4. Then, as shown in FIG. 5, the Y-axis position of the lower surface 4a of the stage 4 is detected.

That is, as shown in FIG.
The gradation levels of each pixel are added over the width r of 2a. In this case, the data indicating the bright gradation is added as valid data. FIG. 5B is a graph showing the added value q for each position on the Y-axis, and it can be seen that the value rapidly changes at the stage lower surface 4b position where the dark image is switched to the bright image. Therefore, if this graph is differentiated, it becomes as shown in FIG. 5 (c), and the differential value q'is at the peak.
Is determined as the Y coordinate position of the coordinate position 13a of the lower surface 4b of the inspection stage 4. The X-axis position of the coordinate position 13a is the center position of the area 12a. Similar processing is performed in area 12
This is also performed for b, and its coordinate position is determined. Then, a line segment connecting these left and right coordinate positions is determined as the lower surface 4b of the stage 4 and is used as a reference line for inspecting the lead 2. As described above, since the bright image is above the stage lower surface 4b and the dark image is below the stage lower surface 4b, it can be seen that the reference line is reliably determined with good contrast (step 104).

Next, as shown in FIG.
The tip surface 3 of each lead 2 that includes a and is an inspection target
A region 11 including a, 3b, 3c, 3d and 3e is cut out. Then, in the area 11, the above step 10 is performed.
In 2, the pattern matching with the already registered model image 14 is performed, and the coordinate position of each lead tip surface is detected. Here, there are various methods of pattern matching, but for example, a correlation method using a correlation coefficient is effective. The pattern 14 is matched with the lead tip surfaces 3a ... And the coordinate position having the best correlation is set as the coordinate position of each lead tip surface 3a. Here, since only the lead tip surfaces 3a ... Are obtained as a dark image and the periphery thereof is a bright image, an image that is not affected by the nonuniform cutting shape or the bending of the leads is obtained. The coordinate position of the tip surface can be accurately obtained. Also, the lower surface 4 of the stage
Since the dark image is below b, this and the lead tip surface 3
Image processing can be reliably performed without the possibility that the dark images of a ... Overlap with each other (step 105).

Next, based on the coordinate position of the stage lower surface 4b detected in step 104 and the coordinate position of each lead tip surface 3a detected in step 105, each tip surface 3a.
And the lead pitch are calculated.

That is, as shown in FIG. 4, with respect to the tip surface 3a, the distance l1 between the reference line 4b and the lower surface of the tip surface 3a.
Is calculated, and the floating amount d1 is obtained by subtracting the plate thickness h of the stage 4 from the calculated value l1. Similarly, the floating amount d2 between the adjacent tip surfaces 3b is also obtained based on the distance l2. On the other hand, the lead pitch p1 for the adjacent leads 2 and 2 is obtained as a deviation between the X-axis coordinate position of the tip surface 3a and the X-axis coordinate position of the tip surface 3b (steps 107 and 108).

Next, it is judged whether or not the calculated floating amounts d1 and d2 are less than or equal to the allowable value dd input in step 101. As a result, the lead 2 having the allowable value dd or less
Is a "good product", and the lead 2 larger than the allowable value dd is a "bad" product. Also regarding the calculated lead pitch p1, p1 is equal to or less than a value obtained by adding the allowable value dp also inputted to the lead pitch pt inputted at step 101 and is not less than a value obtained by subtracting the allowable value dp from the lead pitch pt. It is determined whether or not it is within the range. In this case, if it is within the above range, it is determined as "non-defective", and if it is out of the range, it is determined as "defective" (step 109). The above calculation and determination processing is performed for each lead 2 (determination YE in step 110).
S) If all the leads 2, that is, the processes for the number ln are completed (NO at step 110), the inspection is completed. In this case, if it is determined in step 109 that all pins 2 ... Are "good", IC1 is determined as "good". On the contrary, if there is even one determination of "bad", IC1 is determined as "bad".

In the embodiment, the light is emitted from three directions as shown in FIG. 1. However, the present invention is not limited to this, and the illumination is appropriately omitted depending on the material of the inspection stage. Is also possible. The point is that the illumination method is such that only the lead tip surface 3 of each portion of the IC 1 is obtained as a dark image.

In the embodiment, the lower surface 4 of the inspection stage 4 is also used.
Although b is used as the reference line, it is also possible to use the upper surface 4a as the reference line. In this case, if the inspection stage 4 is made of a material that does not transmit light and the light sources 3a and 3c are used, the inspection stage 4 becomes a dark image, and the upper surface 4a can be captured as a light-dark boundary line.

Further, in the embodiment, an image including the entire lead tip portion is generated as the model image 14, but only the lower surface and side surface of the lead tip portion are included as shown in 14 'of FIG. 6 (b). The image may be used as a model.

Although the IC is assumed to be inspected in the embodiments, the present invention is not limited to this and can be applied to the inspection of various parts.

[0029]

As described above, according to the present invention, each part of the component except the side face of the component to be inspected is illuminated, and only the side face of the component is obtained as a dark image by the image pickup means. Therefore, if the side surface of the component is, for example, the tip end surface of the IC, an image that is not affected by the uneven cutting shape or the bending of the lead can be obtained, and the inspection can be performed accurately.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of an appearance inspection apparatus for parts according to the present invention.

FIG. 2 is a flowchart illustrating a process executed by the image processing apparatus shown in FIG.

FIG. 3 is a diagram showing an image captured by the television camera shown in FIG.

FIG. 4 is a diagram illustrating an arithmetic process according to an embodiment.

FIG. 5 is a diagram illustrating image processing according to an embodiment.

FIG. 6 is a diagram showing a model image used for pattern matching in the embodiment.

FIG. 7 is a diagram showing a configuration of a conventional inspection device.

FIG. 8 is a diagram showing a configuration of a conventional inspection device.

9 is a diagram showing an image captured by the apparatus shown in FIG.

10 is a diagram showing an image captured by the device shown in FIG.

[Explanation of symbols]

 1 IC Package 2 Lead 3 Lead Tip Surface 4 Inspection Stage 5a Light Source 5b Light Source 5c Light Source 6 Television Camera 7 Image Processing Device

Claims (4)

[Claims] 1. A side surface of a component placed on an inspection table and a line indicating an upper end or a lower end of the inspection table are simultaneously imaged by an image pickup means, and the line obtained by the image pickup is used as a reference line. In a component appearance inspection apparatus for inspecting a defect in the appearance of the component according to a side surface shape of the component, in the component, only the side face imaged by the image capturing unit is obtained as a dark image by the image capturing unit. Appearance inspection device for parts that illuminates each part of the removed parts. 2. The material of the inspection table is a material that transmits light for illumination, and is a side surface opposite to the upper surface of the component, the lower surface of the inspection table, and the side surface of the component imaged by the imaging means. 2. The visual inspection apparatus for a component according to claim 1, wherein the component is inspected for the external appearance of the component by irradiating each of them with light for illumination and using the line indicating the lower end of the inspection table as a reference line. 3. A material of the inspection table is a material that does not transmit light for illumination, and is used for illumination toward a side surface opposite to a top surface of the part and a side surface of the part imaged by the imaging means. 2. The visual inspection apparatus for a component according to claim 1, wherein the visual inspection of the component is performed by irradiating the above light and using the line indicating the upper end of the inspection table as a reference line. 4. The visual inspection apparatus for a component according to claim 1, wherein the component is an IC package having a lead group on a side, and a side surface of the component obtained as a dark image by the image pickup means is a tip end face of the lead. ..