Metal working – Method of mechanical manufacture – Electrical device making
Reexamination Certificate
2000-10-23
2002-10-01
Fulton, Christopher W. (Department: 2859)
Metal working
Method of mechanical manufacture
Electrical device making
C033S645000, C382S151000, C438S016000
Reexamination Certificate
active
06457232
ABSTRACT:
BACKGROUND OF INVENTION
1. Field of Invention
The present invention relates to a jig for use in measuring an accuracy with which a mounting device mounts at least one member on a substrate and a method of measuring, with the jig, the accuracy.
2. Related Art Statement
Recently, there has been a strong demand to improve an accuracy with which electric components (ECs) are mounted on a printed-wiring board (PWB), so as to meet such requirements to shorten a pitch at which each EC has its lead wires and increase a density at which the ECs are mounted on the PWB. To this end, first, it is needed to measure a positional error of each EC mounted on the PWB. An example of a positional-error measuring device is disclosed in Japanese Patent Document No. 4-344411. This positional-error measuring device includes (a) a plurality of standard chips, (b) a jig on which the chips are mounted by an EC mounting device, (c) an image taking device which takes respective images of the chips mounted on the jig, and (d) a computer which compares image data representing each of the respective images of the chips taken by the image taking device, with reference image data, and determines at least one positional error of each of the chips mounted on the jig by the EC mounting device. This positional-error measuring device may be provided as an independent device for exclusive use in measuring the positional error, or as an integral portion of the EC mounting device.
The positional-error measuring device sequentially takes the respective images of the chips mounted on the jig, compares a batch of image data representing each of the taken images of the chips, with a batch of reference image data which are prepared in advance, and determines at least one positional error of each chip. The batches of image data representing the respective images of the chips are obtained by repeating (a) feeding, relative to the image taking device, the jig in a direction parallel to the opposite major surfaces of the jig and (b) taking an image of each chip being positioned at an image-take position. However, the thus measured positional error of each chip contains not only a mounting error of the EC mounting device but also a feeding error of a feeding device which feeds the jig relative to the image taking device. To solve this problem, the feeding error of the feeding device is measured in advance, and this feeding error is subtracted from the above-indicated measured positional error, to determine finally a mounting error of the EC mounting device. More specifically described, in order to measure a feeding error of the feeding device, a jig having a reference mark is prepared, and the jig is fed by the feeding device in the same manner as that in which the images of the chips are taken, so that an image of the reference mark is taken and, based on the taken image, the feeding error of the feeding device is determined. Based on this feeding error, the above-indicated measured positional error is corrected to determine finally the mounting error of the EC mounting device.
Thus, the conventional positional-error measuring device cannot help measuring a mounting error containing a feeding error and, to avoid this problem, the feeding error is measured in advance to correct the measured mounting error. Therefore, it needs a long time to finally obtain the corrected mounting error, and it is difficult to improve the accuracy of measurement of the mounting error. Moreover, since the mounting error containing the feeding error, and the feeding error itself are measured at different times, the jig used to measure the mounting error, and the jig used to measure the feeding error may be set, on the EC mounting device, at different positions, which may lead to producing a setting error which may, in turn, be contained in the above-indicated, measured positional error.
SUMMARY OF INVENTION
The present invention provides a jig, a standard chip, a jig set, an accuracy measuring method, an accuracy-measuring-program recording medium, and a mounting apparatus which have one or more of the following technical features that are described below in respective paragraphs given parenthesized sequential numbers (1) to (27). Any technical feature that includes another technical feature shall do so by referring, at the beginning, to the parenthesized sequential number given to the latter feature. Thus, two or more of the following features may be combined, if appropriate. Each feature may be accompanied by a supplemental explanation, as needed. However, the following features and the appropriate combinations thereof are just examples to which the present invention is by no means limited. In addition, in the case where one technical feature recites a plurality of items, it is not essentially required that all of those items be simultaneously employed. That is, it is possible to select and employ only a portion (one, two, . . . , but not all) of those items of that technical feature
(1) According to a first feature of the present invention, there is provided a jig for use in measuring an accuracy with which a mounting device mounts at least one proper member on a proper substrate, wherein the improvement comprises that the jig is set, in place of the proper substrate, on the mounting device, that at least one standard chip is mounted on the jig by the mounting device, and that the jig has at least two reference marks at respective positions which assure that respective images of the reference marks and an image of at least a portion of the standard chip mounted on the jig are simultaneously taken by a single image taking device, so that the accuracy is determined based on the images taken by the image taking device. The standard chip has the standard dimensions of the proper member and accordingly, when an image of at least a portion of the standard chip mounted on the jig is taken, the taken image can be used to determine the accuracy. Each proper member may be used as the standard chip, because each proper member should have the standard dimensions.
In the case where the standard chip is mounted on the jig according to the first feature (1) and the respective images of the reference marks of the jig and the image of the portion of the standard chip mounted on the jig are simultaneously taken by the single image taking device, at least one relative position of the standard chip relative to the jig can be determined and, based on the thus determined at least one relative position, at least one positional error of the standard chip relative to the jig can be determined. The at least one positional error may comprise at least one of respective positional errors of the chip relative to the jig along an X axis and a Y axis perpendicular to each other and an angular (i.e., rotation-positional) error of the chip relative to the jig about a Z axis perpendicular to the X and Y axes. The thus determined positional error of the chip does not contain the above-indicated feeding error that is contained in the mounting error measured by the conventional positional-error measuring device. Thus, owing to the jig according to the first feature (1), the mounting accuracy of the mounting device can be measured with high reliability or accuracy. In addition, since it is not needed to measure the feeding error in advance or remove the feeding error from the preliminarily measured mounting error, the mounting accuracy can be measured with high efficiency. Meanwhile, the mounting accuracy may be measured by an exclusive mounting-accuracy measuring device, independent of the mounting device, in such a manner that at least one standard chip is mounted on a jig set on the exclusive device. However, in the case where the mounting device is provided with the image taking device and a moving device which moves one of the image taking device and the jig relative to the other, the mounting device can measure its mounting accuracy. In this case, it is not needed to use the exclusive mounting-accuracy measuring device, which leads to reducing the cost needed to measure the mo
Isogai Takeyoshi
Katsumi Hiroshi
Murai Masaki
Fuji Machine Mfg. Co., LTD
Fulton Christopher W.
Oliff & Berridg,e PLC
LandOfFree
Jig for use in measuring mounting accuracy of mounting... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Jig for use in measuring mounting accuracy of mounting..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Jig for use in measuring mounting accuracy of mounting... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2942863