JPH09113238A - Quality inspection method and its device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively inspect visually a product through more inexpensive structure than heretofore, eliminate overlooking of inspection items as well as variance of judgment standard, and to quickly cope with the production line for many kinds and small quantity. SOLUTION: A picture of an object 4 to be inspected which is sensed by an image sensing device 1 and a picture of a quality sample for the object 4 are alternately displayed on the same screen 3 by a controller 2. Then, when both pictures are displayed on the same screen at the sametime, they are laid overlapping each other so as to compared the object 4 with the quality sample thereof.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for visually determining the quality of products and an apparatus therefor.

[0002]

2. Description of the Related Art In any industrial field, quality inspection is often required for products produced in the industry. In addition, the contents and items of quality inspections are quite different depending on the industrial field and products, but
It can be said that the inspection method for judging the quality of a product based on its appearance is an important method in common. For example, in the field of agriculture, forestry and fisheries, visually inspecting the appearance of harvested products is extremely important for various purposes such as price determination and prevention of outflow of defective products. In addition, in the industrial field such as metal parts processing, in addition to design dimensions of products, there are cases where it is required to inspect appearances due to dents, plating defects, and the like. Further, even in a field where a large number of electronic components are mounted on a substrate to produce circuit components, there are cases where an appearance inspection determines an item that cannot be detected only by an in-situ electrical characteristic inspection in a process. For example, there are mounting defects / drops of components such as heat sinks, scratches in wiring, and solder defects.

[0003]

The visual inspection of the product is
A visual inspection by a human is common. However, the visual inspection by humans usually does not require expensive equipment costs, but there are problems peculiar to the sensory inspection such as oversight of inspection items, oversight of defects, and change of judgment criteria.

As a method of inspecting the appearance of a product, a method is known in which an image of the appearance of the product is loaded into a computer, various image processing is performed, and the computer itself determines the quality. For example, in the field where the above-mentioned circuit component is produced, an example in which an image of a non-defective product of the circuit component is stored in advance and the difference between the image of the product and the image of the non-defective product is processed and judged by software can be given.

However, there is a problem that such an appearance inspection apparatus by image processing using a computer becomes a very expensive system including quality judgment software.
Further, in such a conventional appearance inspection apparatus, it is usually difficult to set conditions for quality judgment, so that it is not possible to quickly cope with high-frequency switching of the production line in a production system for a large number of small products. There is.

An object of the present invention is to efficiently inspect the quality of a product by visual inspection with a less expensive device configuration than the conventional one, and overlook inspection items, overlook inspection items, and change judgment criteria. It is an object of the present invention to provide a quality inspection method capable of suppressing the above-mentioned problems and capable of quickly responding to a production line of a wide variety of products in small quantities. Another object of the present invention is to provide an apparatus capable of carrying out the quality inspection method of the present invention.

[0007]

The quality inspection method of the present invention has the following features. (1) An image of an object to be inspected and an image of a quality sample of the object to be inspected are alternately and temporally switched and displayed on the same display screen, and these are displayed in the same position. A quality inspection method characterized by comparing an inspected object with a quality sample of the inspected object by displaying them at positions where they coincide with each other and overlap each other when they are simultaneously displayed on a screen.

(2) The quality inspection method according to (1), wherein the inspection object is a substrate on which electronic components are mounted.

(3) The time during which the image of the object to be inspected and the image of the quality sample of the object to be inspected are displayed on the display screen for 0.01 seconds to 10 seconds, respectively, while switching between these images. The time that neither image is displayed in 0.0
The above (1) to (2), which exists for 01 to 10 seconds
The quality inspection method described.

(4) The above-mentioned (1) to (3), wherein the display screen is a color display screen, and the image of the inspection object and the image of the quality sample of the inspection object are displayed in color. Quality inspection method.

(5) A method of comparing the image of the object to be inspected with the image of the quality sample of the object to be inspected by an arithmetic unit to inspect the quality of the object to be inspected is further added and used together. The quality inspection method according to items 1 to 4.

The quality inspection device of the present invention has the following features. (6) An apparatus for performing the quality inspection method according to any one of (1) to (5), comprising: (a) a photographing device; and (b) an image of the inspection object photographed by the photographing device and the inspection object. A quality inspection device comprising at least a control device capable of temporally alternately switching and displaying an image of a quality sample on a display screen, and (c) a display screen.

(7) The quality inspection device according to the above (6), which has any of the following features. (D) The number of photographing devices is one, and the control device has a storage device that holds, as data, the image of the photographing object photographed by the photographing device, and the images displayed by the control device are alternately switched in time. The image of the object to be photographed by the photographing device at that time and the image of the object to be photographed held as data in the storage device. (E) An image displayed by the plurality of image capturing devices, which are alternately switched by the control device in time, is an image of the image capturing target imaged by the plurality of image capturing devices at that time.

(8) An arithmetic unit capable of inspecting the quality of the object to be inspected by performing image processing on the image of the object to be inspected and the image of the quality sample of the object to be inspected and comparing is added. The quality inspection device according to (6) or (7).

[0015]

By displaying the image of the inspection object and the image of the quality sample by alternately switching them as described above, the difference between the inspection object and the quality sample, such as the presence or absence of parts and the difference in external shape and appearance, Only the part appears on the display screen as if it were blinking. Hereinafter, such an action is generically referred to as a "blinking action". Due to this blinking effect, the difference between the inspected object and the quality sample is emphasized more easily and can be found more easily.

According to the present invention, when the image of the inspection object and the image of the quality sample are alternately displayed on the same display screen,
Positionally, when these are displayed on the same display screen at the same time, they are displayed at positions where they coincide with each other and overlap, but in that case, "match with each other and overlap" means
Not only the theoretical perfect match, but the deviation may be included within the range where the above-mentioned blinking action is obtained. Switching between images means not only that one image disappears at the same time as or after the other image disappears, but also that the other image appears before one image disappears. It also includes the switching of images so that they temporarily overlap.

By displaying the image of the object to be inspected and the image of the quality sample in color, the difference between the object to be inspected and the quality sample may be further emphasized. For example, when the object to be inspected is a board on which electronic components are mounted, the electronic components often have a colorful appearance. When one of such colored parts is missing, the presence / absence of the part on the display screen more markedly shows a blinking action.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION The quality inspection apparatus of the present invention will be exemplified below, and the quality inspection method according to the present invention will be described. FIG. 1 is a diagram schematically showing an example of the configuration of a quality inspection device according to the present invention. As shown in the figure, the quality inspection device according to the present invention has at least a photographing device 1, a control device 2, and a display screen 3. In the example of the figure, the number of image capturing devices is one, and the control device 2 has a storage device (not shown) that holds, as data, an image of an image capturing target captured by the image capturing device. Further, 4 is an inspection object,
It is a board on which electronic components are mounted. The substrate is hatched for clarity.

Using the apparatus having the above structure, quality inspection is performed according to the following procedures. . A quality sample (not shown) of the object to be inspected is photographed by the photographing device 1, the image is captured as data, and this is stored in the storage device of the control device. . The object to be inspected is photographed by the photographing device 1. The shooting location is
The quality sample and the inspected object are in the same place. Further, when these images are displayed on the display screen at the same time, the photographing position is determined so that these images match and overlap each other on the display screen. . By the control device, an image of the object to be imaged (object to be inspected) that the imager is currently taking, and an image of the object to be imaged (quality sample) held as data in the storage device,
They are displayed alternately on the same display screen 3 by switching them temporally. . The inspector looks at the display screen. If there is a difference between the inspected object and the quality sample, that part appears as the blinking action on the display screen. The inspection can be completed by easily detecting the difference in external appearance and external shape.

FIG. 2 is a diagram schematically showing another example of the structure of the quality inspection device according to the present invention. The example in the figure is an example in which two image capturing devices are used and the control device 2 has a function of alternately switching the images sent from the two image capturing devices in time. Further, in the figure, 4 is an inspection object, and 4a is a quality sample of the inspection object.

Using the apparatus having the configuration shown in FIG. 2, quality inspection is performed by the following procedures. . The quality sample 4a of the inspection object is photographed by the photographing device 1a. . The inspection object 4 is photographed by the photographing device 1. The order of and may be reversed. In addition, the shooting location is the same as that described in FIG. . By the control device, the image of the inspection object 4 photographed by the photographing device 1 and the image of the quality sample 4a photographed by the photographing device 1a are temporally alternately switched and displayed on the same display screen 3. indicate. . Similar to the description of FIG. 1 above, the inspection operator looks at the display screen, detects the difference between the inspection object and the quality sample, and completes the inspection.

The above-mentioned photographing device may be one that can transmit a photographed image as a signal to the control device, for example, a so-called image pickup camera such as a general home video camera or a CCD camera. Further, the photographing device may be one that continuously outputs the video signal in real time while photographing the photographing target, or may be one that outputs only the still image at the moment. Further, it may be one that can be magnified and photographed like a micrograph. The signal of the image captured by the camera is
Data may be converted into data on either the photographing device side or the control device side, and the type of the signal is not limited. For example, general analog video signals such as NTSC, YC, RGB, and various digital signals can be used. As in the configuration example shown in FIG. 2, when the control device temporally alternately switches and displays the images sent from the two image capturing devices, the storage device that holds the images as data can be deleted. Is.

The control device has at least a function of alternately switching the image of the object to be inspected and the image of the quality sample on the display screen in time. Other functions of the control device change depending on what kind of signal source is used for the image of the object to be inspected and the image of the quality sample. For example, a storage device is required in the mode shown in FIG. From the viewpoint of freely recording and reading image data to and from the storage device in a short time, it is preferable to add a computer function to the control device. Further, as shown in FIG. 2, when switching images from a plurality of photographing devices, the control device can be configured with a simple switching function.

When the image of the object to be inspected and the image of the quality sample are displayed on the same display screen, the description of the above operation will be made depending on the timing and the temporal ratio at which they are alternately switched. Since the blinking action changes as described above, it may be appropriately adjusted according to the inspection object and the situation. The time for displaying the image of the object to be inspected and the image of the quality sample on the display screen is preferably about 0.01 seconds to 10 seconds, and particularly in the actual inspection step, 0.05 seconds to
About 0.3 seconds is a preferable time. On the other hand, on the other hand,
The timing of image switching may be left to the operation of the inspection operator to manually switch the images.

When switching between the image of the object to be inspected and the image of the quality sample, a method of temporarily overlapping these images with each other on the display screen and switching between these images is mainly used. The method may be arbitrarily selected up to the method of switching so that there is a time when the image is not displayed. When there is a time when neither image is displayed, the blinking action becomes weaker as the time becomes longer. Therefore, the time during which neither image is displayed is preferably about 0.001 seconds to 10 seconds, and in the actual inspection step, it is preferably set to 0.001 seconds or more, which is as short as possible.

The time relating to image switching may be manual, by a timer element, or created by computer software. As a circuit relating to image switching, a circuit corresponding to the type of image signal to be switched is used.

FIG. 3 schematically shows an example of a circuit relating to switching when a video signal of an object to be inspected and image data of a quality sample stored in a memory are switched and displayed on a display screen. FIG. In the example shown in the figure, an image of a work, which is an object to be inspected, is sent to the image memory board as an NTSC signal, is once converted as image data, and is stored in the frame memory 1. on the other hand,
The image data of the quality sample acquired in advance is read from the hard disk by the computer, sent to the data compression / expansion board by the bus line 1 to release the state of the compressed data, and further sent to the image memory board, and the frame It is stored in the memory 2. The image data held in the frame memories 1 and 2 of the image memory board is switched by a computer command through the bus line 2 and is output as an analog RGB signal to the monitor. The data compression / decompression board is a device that compresses the image signal captured by the video camera into a small amount of data when writing it to the storage device (hard disk in the figure) and restores it to the original data when reading it. This is preferable in order to utilize the capacity of the storage device more effectively.

As another example, when a plurality of image pickup devices are used at the same time, if the image signals sent from each are switched, they are switched using a switch, a relay, a contactless switching element, or the like. You can send it to a TV receiver.

The image of the object to be inspected and the image of the quality sample are
When displaying on the same display screen, it is preferable to display the positions of these images at the same position on the display screen, but as described in the explanation of the above operation, within the range where a blinking operation can be obtained. Therefore, it may include a deviation from each other. The range of the deviation depends on the content of the object to be inspected, but it is preferable that the deviation is within about 3 mm on the display screen. In order to display the image of the object to be inspected and the image of the quality sample at the same position on the same display screen, the actual object to be inspected and the quality sample can be set at a fixed position with respect to the imaging device. Alternatively, a specific jig or XY table may be manufactured. Further, after capturing these images as data, the display position on the display screen may be corrected to the same position by processing the data by the computer.

The storage device is not particularly limited in its storage medium and storage method such as digital or analog.
It is only necessary that the image of the object to be photographed can be held as data for a desired time, and the data can be reproduced as an image on the display screen again. For example, the control device may be a simple signal switching device and the storage device may be an external video recorder. Further, if the control device is mainly composed of a computer, as the storage device, all storage devices connectable to the computer such as a memory such as a RAM and a disk device can be used.

A preferable display screen may be determined by an output signal of the control device, and a general television receiver, various monitors used for displaying a terminal of a computer, and the like are used. Further, as described in the above description of the operation, a color display screen may be used as the display screen, and the inspection object and the image of the quality sample may be displayed in color.

The contents to be displayed on the display screen may be not only the images to be compared, but also characters and symbols may be displayed in an overlapping manner so as to further clarify the point of interest. For example, even when a substrate on which a large number of components are mounted is used as an object to be inspected, it is often the case that the inspection is practically limited to specific important components. In such a case, the number is displayed at the position of the part to be inspected on the display screen, and each time the inspection operator presses the switch, the numbers are sequentially erased or numbered so that the inspection object is guided to the inspection object in the order of the number. For example, blinking.

Ancillary functions for assisting the judgment on the display screen, a function for managing the contents of the judgment as data, and a function for statistically processing the data may be added freely. . Further, the operation panel is preferably set according to the type of the inspection object. For example, it is possible to preset a switch for an item of defective content that frequently occurs in advance to make the determination result input more efficient.

The object to be inspected is not particularly limited from industrial products to products and catches in the agriculture, forestry and fisheries industry, but in addition to the board on which electronic parts are mounted, as in the above example,
Products that can be produced in the same shape according to the design value, such as parts manufactured by machining and molding, are preferable because the blinking effect becomes remarkable.

As a quality sample, a non-defective sample of the inspection object,
A sample indicating a boundary between a good product and a defective product (a limit sample), a defective product sample, or the like may be freely selected according to what is to be determined. The quality sample may be selected many times for each production lot, or only the quality sample may be selected as the quality sample.
Further, for each different product, all the quality sample images may be stored in advance in the storage device, and may be called out for use.

The quality inspection method according to the present invention may be further used in combination with a method of processing image data by an arithmetic device and automatically determining the quality of a specific item. For example, it is used in combination with a method of inspecting the quality of the inspection object by comparing the image of the inspection object with the image of the quality sample by image processing by a computer. Therefore, the control device may have a function capable of automatically determining such quality internally, or may be linked with an external computer. Therefore, in constructing the quality inspection apparatus according to the present invention, the automatic quality inspection function may be provided internally, or data may be exchanged and linked as an external apparatus. In such a case, which part of the inspection object is displayed on the display screen and which part is to be assigned to the automatic quality inspection function may be determined according to the application.

[0037]

EXAMPLES The present invention will be more specifically described below with reference to examples. In this embodiment, a quality inspection device was actually manufactured, applied to the appearance inspection process of the production line, and used to inspect the mounting state of components on the board. FIG. 4 shows the display screen 3 of the quality inspection device, the control device 2, and the operation panel unit 2 of the control device.
It is a figure which shows only a. Illustrations of the imaging device and production line are omitted.

As shown in the figure, the display screen 3 shows an area to be inspected on a substrate which is an object to be inspected. There are a total of seven mounted parts of the object to be inspected, such as an IC, a capacitor, a resistor, and a transistor, and the contents of the inspection are mainly the missing of the parts and the soldering quality of the terminals of the IC and the lead parts of the elements. Numbers from 1 to 7 are displayed on the display screen corresponding to each part, and the numbers are sequentially erased from 1 each time the button for determining OK or ... Let A comment is displayed below the display screen 3 to display information such as the product model and lot. As shown in the figure, the operation panel has push button switches arranged to count and classify the appearance defects that often occur in this product. Push button switches include "missing" for "missing", "short" for "short circuit", "scratch",
Characters indicating fault content such as "distortion" are entered.

In this embodiment, the number of image pickup devices is one, and the image data is held in the internal memory of a good sample of the object to be inspected as a quality sample in advance.

In the inspection, the time during which the image of the object to be inspected and the image of the quality sample were displayed on the display screen was set to 0.1 seconds. Further, the time during which neither image is temporarily displayed while switching between these images is 0.
It was less than 01 seconds.

When the appearance of 100 pieces was inspected by the device having such a specification, a blinking action was well shown for the missing parts due to a mounting error, and it was possible to check without oversight. In addition, since quality samples related to soldering can be seen without moving the line of sight from the object to be inspected, it is possible to always make stable judgment criteria, and the difference from the good sample is emphasized. Was done and could be done easily. Further, it was found that the inspection was completed in about 50% of the time compared with the normal visual inspection, and the efficiency was good.

[0042]

According to the quality inspection method and the apparatus thereof of the present invention, it is possible to efficiently inspect with a structure of an apparatus which is cheaper than the conventional one, and to overlook inspection items, overlook inspection items and change judgment criteria. Became. In addition, it has become possible to quickly respond to production lines for a wide variety of products in small quantities.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing an example of the configuration of a quality inspection device according to the present invention.

FIG. 2 is a diagram schematically showing another example of the configuration of the quality inspection device according to the present invention.

FIG. 3 is a diagram schematically showing an example of a circuit relating to switching of images to be displayed in the quality inspection device according to the present invention.

FIG. 4 is a diagram schematically showing a part of the configuration of the quality inspection device manufactured in the embodiment of the present invention.

[Explanation of symbols]

 1 Imaging Device 2 Control Device 3 Display Screen 4 Inspected Object

Claims (8)

[Claims] 1. An image of an object to be inspected and an image of a quality sample of the object to be inspected are alternately and temporally switched and displayed on the same display screen, and they are positionally the same. The method for quality inspection is characterized by comparing the inspected object with a quality sample of the inspected object by displaying them at positions which coincide with each other and overlap each other when they are simultaneously displayed on the display screen. 2. The quality inspection method according to claim 1, wherein the inspection object is a substrate on which electronic components are mounted. 3. The time during which the image of the inspection object and the image of the quality sample of the inspection object are displayed on the display screen is 0.
01 seconds to 10 seconds, and the time during which neither image is displayed while switching between these images is 0.001
3. The quality inspection method according to claim 1, wherein the quality inspection method is present for 10 seconds to 10 seconds. 4. The quality inspection method according to claim 1, wherein the display screen is a color display screen, and the image of the inspection object and the image of the quality sample of the inspection object are displayed in color. . 5. A method for inspecting the quality of the inspected object by comparing the image of the inspected object with the image of the quality sample of the inspected object by an arithmetic unit is further added and used together. The quality inspection method described in 1 to 4. 6. An apparatus for performing the quality inspection method according to claim 1, comprising: (a) a photographing device; and (b) an image of the inspection object photographed by the photographing device and the quality of the inspection object. A control device capable of temporally alternately switching and displaying a sample image on a display screen described later; and (c) a display screen,
A quality inspection device having at least the following. 7. (d) The photographic device is singular, the control device has a storage device for holding, as data, an image of the photographic object photographed by the photographic device, and the control device switches alternately in time. The image to be displayed is the image of the object being photographed by the image capturing device at that time and the image of the image capturing object held as data in the storage device, or (e) there are multiple image capturing devices. Then, the image displayed by the control device by alternately switching in time is the image of the image-capturing target imaged by the plurality of image-capturing devices at that time.
The quality inspection device according to claim 6. 8. An arithmetic unit capable of inspecting the quality of an inspected object by performing image processing on an image of the inspected object and an image of a quality sample of the inspected object and comparing them. 6
Or the quality inspection device described in 7.