DE102005026630A1 - Identical objects, e.g. electronic printed circuit boards, inspecting method, involves recording, storing and displaying image of printed circuit board to be inspected after inspection of another board to be inspected - Google Patents

Abstract

The method involves recording and storing a reference image of a correct object e.g. printed circuit board (8). An image of an object to be inspected is recorded from the same line of vision and is stored. The reference image and the image of the object to be inspected are alternatively displayed on an optical display unit in the same position. An image of proximate object to be inspected is recorded, stored and displayed after the inspection of former object to be inspected. Independent claims are also included for: (1) a device for optical inspection of identical objects in nominal condition; and (2) an application of a device for optical inspection of identical objects in nominal condition.

Description

The The invention relates to a method for optically checking in its nominal state identical objects, a device for optical checking and a use of this device.

In In the electrotechnical industry there are applications where manually determined components in a prescribed pattern attached to the printed circuit boards. This happens, for example, by Pressing. So far, it is customary the correct assembly visually inspect such printed circuit boards. This happens like this that, for example, the person who made the assembly, the Checked result using a correct pattern or template. there then becomes component for Component checked. This does not lead only to a very fast fatigue the person concerned, but also to easily overlook mistakes become.

Also known are elaborate Automated optical inspections, but with the disadvantage that setting up for a particular subject is time consuming and the devices themselves are high Investment costs need.

Of the Invention is based on the object, a simple einzurichtende and easy to perform possibility to create objects to check for accuracy, the are identical in their nominal state and where a deviation is visually recognizable from the nominal state. In particular, it should be at the items to be checked for circuit boards to act with components in which the absence of a component or the use of a different in its size or color Component represents an error.

to solution this task strikes the invention a method with the features mentioned in claim 1 and / or a device with the features mentioned in claim 11 and / or a use with the features mentioned in claim 18 in front. Further developments of the invention are the subject of the respective dependent Claims.

The Invention is based on the idea, first of all an object Manually and visually check for correctness. This can also take a lot of time be used as this review for a whole Series of objects to be checked only performed once must become. From this object now recognized as correct a reference picture was taken and saved. The storage must be kept as long as such items are checked. Not from the next one more manually checked item is also an image taken from the same direction and at least temporarily stored. Then the pictures are both objects namely the image of the reference object and the picture just taken of the object to be checked now, alternately displayed on a display device. The frequency The change is set so that the images in the human Eye can not be recognized as a single image. Because the reference object and the object to be checked represented by their respective pictures, and the pictures displayed in the same position appears at the user then when the two items are the same, just a picture. Missing but with an object to be checked a component, or has it a different color or size, this leads to it to blink at the point where the error is. The user not only recognizes immediately that an error exists, but He will immediately be notified of the location of the item the error is present. He can fix the error immediately, or but mark the spot where the defect exists is.

To the review of a Item and the eventual correction of the error can then next Subject to be treated in the same way without again a reference image of a reference object would have to be produced.

Around ensure that identical items also have identical images arise, according to the invention in training be provided that the items before taking the pictures be geometrically aligned, so for example at a same Place to be placed in the same position.

It but is also possible and is within the scope of the invention that prior to taking the pictures the camera opposite aligned to the objects becomes. This can lead to the same result.

A Another possibility proposed by the invention is the Pictures during or after the recording electronically aligned, which is especially true possible is when the objects For example, have clear and defined contours.

As an example of a possible frequency of alternately displaying the images, a Be rich of at least 10 frames per second.

When Display device can in the invention, a computer screen serve, meaningfully stored the images in a computer become. A video camera can then be used to record the pictures. which is connected directly to the computer.

at the use of computers for the recording and saving of images as well as for viewing of course, the alternating pictures can be a computer program also be used to carry out further actions that facilitate the recognition of mistakes. So is the invention For example, the pictures before the display and / or electronically modify before saving, for example the To display pictures as a negative picture. It is also proposed for example, individual color channels to modify.

In repeated development of the invention can be provided, too to change the frequency of the change of images to certain personal characteristics as well the user to consider can.

The The device proposed by the invention contains a Recording, where each a single object are arranged can, which is then recorded by a camera of the device. The camera creates a picture of this object, which is then in a Memory is stored. The memory is such that he can at least save the pictures of two objects. The device contains Furthermore, a display device connected to the memory to the To be able to visually display an image of an object. Farther contains the device is a switching device, with the help of which alternately Pictures of two objects in short intervals being represented.

The Device can have a positioning device in a further development, around the camera opposite the recording or better said that arranged in the recording Position the object in at least two directions. For a third Direction may under certain circumstances, which is also suggested, the camera have a zoom, so that they compensate for this direction without mechanical change of their position can.

According to the invention, in Further development, the device have a device to the To position the object in the recording, that is, all objects of one To arrange the series in the same position. This may be depending on the shape of the object to be checked, to deal with an attack that fixes the object in two directions. The third direction may be defined by the shot itself.

in the Normally, the receptacle is formed horizontally, so that the Object can be hung up easily. The camera can then be vertically above the Recording arranged.

Especially beats the invention to arrange the device in the workplace, where the item is completed so far that it is checked can. If it is the object to be checked a stocked Printed circuit board, the device is so at the placement workstation arranged.

It can be provided that the inclusion of the object in which a Picture is produced by him, at the same time the picture shows, in the object populated becomes.

The The device proposed by the invention is used as follows. It is inserted into the recording a correct object and from this correct object generates a reference image in a permanent memory is stored. This storage as Reference image can be effected by a special key or a command become. This reference image remains in memory and is used for each object to be checked as comparison. The images of the then check items need only be stored as long until the item is checked.

It is natural also conceivable that one for later documentation purposes the images of all checked items continue holds.

Especially It makes sense to use the verification device so to use that review immediately after completion of the object, and that immediately after checking also the Correction done.

Further Features, Details and Benefits The invention results from the claims and abstract, their wording by reference to the content of the description is made, the following description of a preferred embodiment the invention and with reference to the drawing. Hereby show:

1 the front view of an apparatus for performing the method according to the invention;

2 the side view of the arrangement of 1 ;

3 the top view of the arrangement of 1 and 2 ; and

4 the top view of a modified embodiment.

In the very simplified representation of 1 is a tabletop 1 present on which a stop 2 is appropriate. The stop 2 is provided with two wings that enclose a right angle between them. In the area of the back of the table top, so in the back 1 , is a base 3 attached, at the top of a stand 4 sticks up. At the top of the stand 4 is a boom 5 attached, which protrudes forward. At the bottom of the front end of the jib 5 is a camera 6 arranged, whose lens 7 pointing down.

On the tabletop 1 is a circuit board 8th put on and moved so that these on the two wings of the stop 2 is applied. The circuit board 8th has on its top a variety of components 9 on. The tabletop 1 forms together with the stop 2 the recording for the circuit board 8th which represents the object to be checked in the example shown here. In the position in which the circuit board is located here, it is in the field of view of the camera 6 , If a number of printed circuit boards is to be checked, which is smaller or larger than the printed circuit board shown here, so the camera 6 be changed in their position so that this circuit board is then in their field of view, in such a way that the circuit board then fills the field of view to the edges. For this purpose, the camera 6 on the boom 5 in the direction of the arrow 10 movable, see 2 while the boom 5 even in the direction of the arrow 11 can be changed in the vertical direction.

The 3 now shows a plan view from which also can be seen that the circuit board in two directions by the angled stop 2 is positioned while the third direction through the table top 1 given is.

The Details of images on a computer screen will be explained in detail not shown, as this is actually a matter of course is that does not need a graphical representation.

In 4 shows a possibility, as in place of a rigid arm 5 , which is adjustable only in height, a boom 15 can be used, which is composed of two parts pivotable about vertical axes. Here is the camera 6 at the front end of the second part 16 For example, be guided by a parallelogram so that it always produces an image whose side edges parallel to the edges of the attack 2 run.

The swiveling holder is designed to quickly and easily vertical Positioning the camera over to allow the center of the assemblies (to reduce Distortions and to enable the screen-filling Presentation). Since different sized assemblies to one and the same Stop struck at different positions their center The swivel arm offers the comfortable option of positioning quickly change the camera to be able to.

As already mentioned, the camera to be seen in the figures is 6 connected to a computer using a cable. A software installed on the computer records the image transmitted by the camera.

By Actuate a key on the PC saves the software this image. First saves So they are a reference image of a reference object, the before manually or visually for correctness. Subsequently, will the reference object taken from the recording and by the next object to be checked replaced. By pressing the button again on the PC, which can serve another key, this is also transmitted Image saved.

Subsequently, poses the software on the monitor of the PC the two stored images alternately. Both images are shown in the same position. This is done at a frequency of, for example, 10 frames per Second. Due to this frequency, the viewer, due conditional the inertia of the human eye, only a picture true, in which case, when the both items are identical, no difference is recognizable. But is a difference existing between the two pictures, this difference appears as blinking.

On In this way, the user does not need every feature against the template to consider, but he is pointed to the difference by the flashing, and also to the place where the difference exists.

in the Course of reviewing one whole series of objects to be checked remains the first picture, the reference picture, always received, and it will be only the following pictures have been exchanged.

For optimal presentation, the subject should be displayed filling the monitor screen become. To accomplish this, the subject's field of view must be fully filled by the camera. When inspecting objects of different dimensions, the field of view filling the field of view can be achieved by the use of zoom lenses. For the use of cameras without zoom lens, the invention proposes the inclusion of the camera in the holder shown with movable or variable axes. It makes sense to always arrange the camera so that it is directed exactly downwards so as not to create distortions.

Of the Stop must be mounted on the table top so that it stops remains. This can be done either by a heavy weight, with metallic table tops by the use of magnets or otherwise by positive attachment happen.

Claims (21)

Method for visually checking objects that are identical in nominal state ( 8th 1.2, a reference image is taken and stored by a correct object, 1.2 an image is taken from the object to be examined from the same viewing direction and at least buffered, 1.3 the reference image and the test image are alternately on an optical display device in the 1.4 after checking the instantaneous item, the process steps 1.2 and 1.3 repeated for the next item. Method according to Claim 1, in which, prior to taking the pictures, the objects ( 8th ) are aligned geometrically. A method according to claim 1 or 2, wherein prior to taking the images, the camera ( 6 ) against the objects ( 8th ) is aligned. Method according to one of the preceding claims, in the images are aligned electronically. Method according to one of the preceding claims, in in which the alternating frequency of the images is selected in the display such that a viewer clearly recognizes the difference between the two pictures can. Method according to one of the preceding claims, in the pictures are displayed on a computer screen. Method according to the preceding claims, in the recorded images are stored in a computer. A method according to claim 7, wherein the images are before the display and / or before saving electronically modified become. The method of claim 8, wherein individual color channels are manipulated become. Method according to one of the preceding claims, in the frequency of alternation between the representations of the Pictures is changed. Device for optical checking of identical objects in the nominal state ( 8th ), with 11.1 a shot for a single object ( 8th ), 11.2 a camera ( 6 ) for producing an image of the object arranged in the receptacle ( 8th ), 11.3 a memory for storing at least the images of two objects ( 8th ), 11.4 a display device for optical display of the image of each item ( 8th ), and with 11.5 a switching device for alternately displaying the images of two objects ( 8th ) at short intervals. Device according to Claim 11, having a positioning device for positioning the camera ( 6 ) relative to the object arranged in the receptacle ( 8th ) in at least two directions. Apparatus according to claim 11 or 12, comprising means for positioning the article ( 8th ) in the recording. Device according to one of Claims 11 to 13, in which the camera ( 6 ) has a zoom. Device according to one of claims 11 to 14, wherein the receptacle is formed horizontally and the camera ( 6 ) is arranged vertically above the receptacle. Device according to one of claims 11 to 15, in which the Device at a placement workplace for electronic Printed circuit boards is arranged. Device according to one of claims 11 to 16, in which the reception of the device at the same time the receptacle for the completion of the object ( 8th ). Use of a device according to one of claims 11 to 17 for checking objects that are identical in the nominal state ( 8th ). Use according to claim 18, wherein an image of a correct article is stored in a persistent store and checked as a reference against each subsequent article ( 8th ) is used. Use according to claim 18 or 19, in which the inspection is carried out immediately after the completion of the object to be checked ( 8th ) he follows. Use according to any one of claims 18 to 20, in which immediately after the examination of the object to be checked ( 8th ) the correction of an object identified as defective ( 8th ) he follows.