JPH0261506A - Inspection apparatus - Google Patents

Abstract

PURPOSE:To rapidly inspect the mount state of an electronic part to a substrate and to enhance the reliability of the inspection result by providing an oblique floodlight projection means, an imaging means, a judge means, a window setting means and a confirmation means. CONSTITUTION:The slanting shadow of an object 3 to be inspected is generated by oblique flood light due to light sources 5, 7 as oblique flood light projection means. The camera 9 of an imaging means is arranged directly above the object 3 to be inspected, and the image of the object to be inspected and that of the slanting shadow thereof are taken to output image data. A control part 15 is equipped with a judge means for comparing the image data inputted from an A/D converting circuit 13 with the reference data stored in a memory part 17 to judge the mount state of the electronic part concerned, a window setting means for setting a window around the electronic part at the mounting position thereof on the basis of the judge result of said judge means and a confirmation means for confirming whether the judge result of the judge means is correct on the basis of the slanting shadow of the electronic part present in the window.

Description

DETAILED DESCRIPTION OF THE INVENTION [Objective of the Invention 1 (Industrial Application Field) The present invention relates to an inspection device for inspecting the mounting state of electronic components such as ICs on a board on which the electronic components are mounted. The present invention relates to an inspection device that improves the accuracy of determination regarding the mounting state of electronic components.

(Prior Art) An electronic device having an electric circuit section incorporates a large number of boards on which various electronic components are mounted.

Conventional inspection apparatuses for inspecting the state of mounting of electronic components on such boards include a method of examining correlation with preset reference data and a method of determining the outline of electronic components.

Specifically, in the method of examining the correlation, reference data regarding the mounting position of the electronic component or the shape and size of the electronic component is stored in advance in a storage device, and the
The electronic component mounted on the board is determined to be the correct part by imaging the entire board or a part of the board on which the electronic component is mounted using the I-image means and checking the correlation between the image of the imaging means and the reference data. Inspections were made to check whether the electronic components were installed correctly and in the correct position.

In addition, in the method of determining the outline of an electronic component, the mounting state of the electronic component is imaged by an imaging means, the center of gravity of the electronic component is determined from the outline of the electronic component based on the image data of the imaging means, and the center of gravity of the electronic component is determined based on the position of the center of gravity. It was intended to determine whether the parts were installed correctly.

(Problem to be Solved by the Invention) However, in the method of examining the mutual correlation of the shapes of electronic components, the processing process is complicated because it is necessary to recognize the shape of the electronic components, and inspection takes time. Ta.

Furthermore, with the method of determining the outline of an electronic component, it may not be possible to distinguish it from other electronic components depending on the lighting conditions around the electronic component mounted on the board or the relative positional relationship of adjacent electronic components. Ta.

The present invention has been made in view of the above, and an object of the present invention is to provide an inspection device that can quickly inspect the state of mounting electronic components on a board and greatly improve the reliability of the inspection results. do.

[Structure of the invention] (Means for solving the problem) - [In order to achieve the object (d), the present invention provides an inspection device that emits light from diagonally above an object to be inspected mounted on a board. an oblique light means that produces a diagonal shadow of the object to be inspected; an imaging means that images the object to be inspected and the oblique shadow of the object to be inspected from vertically above the object to be inspected, and outputs image information; a determining means for determining the mounting state of the object to be inspected based on image information from the imaging means, and a frame-shaped area based on the mounting position of the object to be inspected based on the determination result of the determining means and a confirmation means for confirming whether the judgment result of the judgment means is correct based on the amount of oblique shadow of the object to be inspected existing within the window.

(Function) The present invention has an oblique light means for projecting light obliquely from above onto an object to be inspected mounted on a board, and the oblique light from the oblique light means illuminates the object to be inspected. Causes oblique shadows. Further, an imaging means is disposed vertically above the object to be inspected, and outputs image information by forming an R image of the object to be inspected and the oblique shadow of the object to be inspected. Further, the determining means determines the state of attachment of the object to be inspected based on the image information from the m@ means. It also has a window setting means for setting a window consisting of a frame-shaped area around the object to be inspected at the mounting position of the object to be inspected based on the judgment result of the judgment means, and the confirmation means is within this window. It is confirmed whether the judgment result of the judgment means is correct based on the amount of oblique shadow of the object to be inspected that exists in the object.

(Example) Hereinafter, an example according to the present invention will be described in detail with reference to the drawings.

First, the configuration will be described with reference to FIG. 1. An electronic component 3 is mounted on a board 1.

This substrate 1 is sequentially transferred in the direction F by a transfer means (not shown) while maintaining a horizontal state.

Light sources 5 and 7 are arranged as oblique light means for projecting light obliquely from above onto an electronic component 3, which is an object to be inspected, mounted on a substrate 1. The optical axis 5a of the light source 5 is set at an angle of depression θ with respect to the substrate 1, and the optical axis 5a
is set at an angle of 45° with respect to a plane parallel to the transfer direction F and perpendicular to the substrate 1. Further, the light source 7 is arranged at a position symmetrical to the light source 5. In other words, the optical axis 7 of the light m7
a is set at a depression angle θ with respect to the substrate 1, and the optical axis 7a is set at an angle of 45° with respect to a plane parallel to the transfer direction F and perpendicular to the substrate 1.

A camera 9 is arranged vertically above the electronic component 3. That is, the substrate 1 is transferred by a transfer means, and the substrate 1 is positioned by a positioning means (not shown) when the electronic component 3 is located within the field of view of the camera 9.

The intensity of the light emitted from each of the pair of lights #i5 and #i7 arranged symmetrically with respect to the optical axis 9a of the camera 9 is such that, for example, the illuminance on the top surface of the electronic component 3 is equal to each other. is set to . Further, the pair of light sources 5 and 7 operate alternately, for example, in synchronization with the image capturing of the camera 9.

Therefore, oblique light from one of the pair of light sources 5 and 7 is projected onto the electronic component 3. In this way, oblique light projected alternately from the light sources 5 and 7 creates an oblique shadow on the electronic component 3, which is the object to be inspected. The area of this oblique shadow reflects the height of the electronic component 3.

A camera 9 composed of a plurality of pixels such as a CCD sensor (charge-coupled device) or a solid-state image sensor is an image processing device 1
The image processing device 11 is connected to the electronic component 3 and outputs images captured from vertically above the electronic component 3 at predetermined intervals of 1 ffu, that is, image data of the electronic component 3 and image data regarding the oblique shadow of the electronic component 3 described above. Output to.

The image processing device 11 is connected to an input device 21 . This input device 21 is equipped with various operation keys such as a numeric keypad, and outputs data related to the shape, size, mounting position, etc. of a plurality of electronic components to the image processing device 11.

Next, the internal configuration of the image processing device 11 will be explained.

The A/D conversion circuit 13 is connected to the camera 9, and when inputted with image data in an analog quantity from the camera 9, it converts it into a digital signal.

The control unit 15 is connected to the A/D conversion circuit 13, and when inputted with image data converted into a digital signal, performs binarization processing for each pixel. Further, the control section 15 has a built-in performance processing means such as a microcomputer, and executes control processing regarding inspection of the mounting state of electronic components. The control unit 15 is connected to the input device 21 and also to the storage unit 17, and stores reference data input from the input device 21, that is, data regarding the mounting state such as the shape, size, and mounting position of each electronic component. Output to storage unit 17. As a result, the storage unit 17 stores information about multiple electronic components.
Data related to the shape, size, and position of each item are stored as reference data. Also, the control section 15
When image data is input from the A/D conversion circuit 13, the determination means compares the input image data with reference data stored in the storage unit 17 to determine the state of attachment of the corresponding electronic component. It is equipped with Also, the control section 15
The apparatus includes a window setting means for setting a window consisting of a frame-shaped area around the electronic component at the mounting position of the electronic component based on the determination result of the determination means. Furthermore, the control section 15 is provided with confirmation means for confirming whether the judgment result of the judgment means is correct based on the oblique shadow of the electronic component existing within the window.

The display section 19 is connected to the control section 15, and the display section 19 is connected to the control section 15.
Displays judgment results regarding the mounting state of electronic components, confirmation results as to whether or not the judgment results are correct, or information regarding various tests based on information from .

Next, the operation will be explained with reference to FIG.

In step 31, the flag F1 is set to OFF. Further, in step 31, the image data from the camera 9 is binarized for each pixel. Subsequently, in step 33, the position and shape of the center of gravity of the electronic component 3 are detected based on the binarized image data. Specifically, the control unit 15 subtracts the image data obtained when only the light source 7 is turned on from the image data obtained when only the light source 5 is turned on, as shown in FIG. An image 71 is obtained. In other words, since the illuminance on the top surface of the electronic component 3 when the light source 5 is turned on and when the light source 7 is turned on is the same, the difference between the image data of the two parts corresponding to the top surface of the electronic component 3 is zero. , an image 71 is obtained around a component image 73 corresponding to the top surface of the electronic component 3 as shown in FIG.

Further, in step 33, windows such as a long axis window 75 and a short axis window 77 that are orthogonal to each other are set as shown in FIG. Since the portion is equal to the outer shape of the electronic component 3, the shape and center of gravity position of the electronic component 3 are calculated based on these images.

For example, as shown in FIG. 4, if there are three or more images of a predetermined number of times existing within the window, when the distance between each image approximately matches the size of the electronic component 3, this image is It is determined that the image is generated on the outer periphery of the component 3.

As shown in FIG. 4, four images 79a having a predetermined value LA or more
, 79b, 79c and 79d exist. If the inner distance l1llIL2 between the shadow 8I79b and the shadow @79d matches the size of the electronic component 3, then the shadows @7b and 79d is electronic component 3
It is determined that the image is generated on the outer periphery of the image.

Furthermore, as shown in FIG. 5, if there is one or less images that are equal to or greater than the predetermined value LA, the above-described determination is performed including the image 79e that exceeds the predetermined value LA and the images 79f and 79g that are less than the predetermined value LA. do.

That is, when the distance between each image matches the size of the electronic component 3, it is determined that the corresponding image is an image generated on the outer periphery of the electronic component.

Conversely, if the distance between the images does not match the size of the electronic component, it is determined that the mounted electronic component 3 is an incorrect component.

Next, in step 35, the angle of the electronic component 3 is detected, that is, the inclination in the horizontal direction is detected. , To be more specific, the sixth
As shown in the figure, windows 81 and 83 are arranged parallel to each other at a predetermined interval, and the inclination of the electronic component 3 is determined by comparing the area values of the image 71 existing within each window.

In step 37, the size of the shape of the electronic component 3 calculated in step 33 is corrected by accurately calculating the external shape of the electronic component. Subsequently, in step 39, it is checked whether the above-mentioned corrected size regarding the shape of the electronic component 3 is correct.

In step 41, a deviation in the mounting position of the electronic component 3 to the substrate 1 is detected. For example, whether the calculated center of gravity position of the electronic component 3 deviates from the reference data stored in the storage unit 17, that is, whether the deviation values of both are within a preset tolerance range, [Tsuku.

Next, in step 43, redundancy determination and standing determination are performed. Specifically, if the width (L2) of the image obtained from the camera 9 is less than or equal to a predetermined width, a determination is made as to whether the electronic component 3 has fallen, that is, is standing. Furthermore, if the width (L2) of the image is equal to or greater than a predetermined value, a determination is made as to whether or not an image due to an electronic component has been added, that is, an excess determination.

Subsequently, in step 45, it is determined whether the part is standing or missing based on the size of the area of the image around the part. In other words, when a part is standing, the shadow becomes longer, and as a result, the area of the shadow increases.
In the case of missing items, the area of the shape is smaller.

Specifically, as shown in FIG. 7, a window W@ consisting of a frame-shaped area is set around a component image 73 corresponding to an image of the top surface of the electronic component 3.

This window W is set in a frame shape surrounded by an outer frame 91 and an inner frame 93. This outer frame 91 is set to a predetermined size in consideration of the shape and height of the electronic component 3. Similarly, the inner frame 93 is set to have the same shape as the outer shape of the electronic component 3. Therefore, depending on the area value of the image 71 existing within the window W, it is checked whether the electronic component 3 is definitely present, that is, whether the various determination results described above are correct. For example, if the area of the shadow @71 existing within the window W is less than a predetermined value 81, it is determined that the electronic component 3 is out of stock;
If the area is 82 or more, which is larger than the predetermined value S1, it is determined that the noise is caused by an image of another electronic component. Further, if the area of the image 71 existing within the window W is within the range of the predetermined values S1 and 82, °electronic component 3
Confirm that it definitely exists and that the above judgment result is correct.

The process then proceeds to step 51 via S2. Step 51
Now, if all the confirmation results in steps 39, 41, 43 and 45 described above are OK, proceed to step 53.
Then, it is determined that the electronic component 3 is a good product.

Conversely, if the result is not OK, the process advances from step 51 to step 55.

In step 55, it is determined whether the flag F1 is ON. If the flag F1 is ON, the process proceeds to step 57, where it is determined that the electronic component 3 is defective.

Further, if the 7-lag F1 is not ON in step 55, the process advances to step 5. In step 5, the image data obtained from the camera 9 is binarized again. Subsequently, in step 61, the flag F1 is set to ON. Subsequently, the process returns to step 33 via steps 61 to 81, and the above-described determination and confirmation operations are repeated.

As described above, when it is determined that the product is defective, the determination operation is repeated and executed again, so that the accuracy of the determination result regarding the attachment of electronic components is further improved.

[Effects of the Invention] As explained above, according to the present invention, a window consisting of a frame-shaped area is set around the object to be inspected at the mounting position of the object to be inspected, and the objects existing within this window are Since the determination result of the determination means is confirmed based on the oblique shadow of the inspection object, inspection processing regarding the mounting of electronic components can be performed quickly, and the reliability of the inspection results can be greatly improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the overall configuration of an inspection device to which the present invention is applied, and FIG. 2 is a diagram showing the control flow in the control section of FIG. 1. , Figure 5,
6 is an explanatory diagram showing various determination operations in FIG. 2, and FIG. 7 is an explanatory diagram showing the window W and the image 11 existing within the window W. 1... Board 3... Electronic component 5.7... Light source 9... Camera 11... Image processing device 15... Control unit

Claims (1)

[Scope of Claims] Oblique light projecting means for projecting light from diagonally above an object to be inspected mounted on a board to produce an oblique shadow of the object to be inspected; an imaging means for photographing an oblique shadow of an object and the object to be inspected and outputting image information; a determining means for determining a state of attachment of the object to be inspected based on the image information from the imaging means; window setting means for setting a window consisting of a frame-shaped area based on the mounting position of the object to be inspected based on the determination result of the means; An inspection device comprising: confirmation means for confirming whether the judgment result of the judgment means is correct or incorrect;