Method of and apparatus for inspecting conductive pattern on printed board
First Claim
1. A method of inspecting a printed board for pattern defects, said printed board being provided with an electrically-conductive pattern and a through hole thereon, said method comprising the steps of:
- (a) photoelectrically reading an image of said printed board;
(b) dividing said image of said printed board into a pattern image representing said conductive pattern and a hole image representing said through hole;
(c) obtaining first and second images by selectively performing one of the steps of;
(c-1) obtaining said first image by magnifying said pattern image and defining said second image with said hole image itself;
(c-2) defining said first image with said pattern image itself and obtaining said second image by magnifying said hole image; and
(c-3) obtaining said first and second images by magnifying said pattern image and said hole image, respectively;
(d) detecting positional relation between said first and second images and representing said positional relation with a parameter value; and
(e) comparing said parameter value with a predetermined reference value and thereby judging whether said conductive pattern has a non-allowable defect or not.
1 Assignment
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Accused Products
Abstract
A printed circuit board (11) is provided with a conductive pattern (P, R) and a through hole (H) thereon. Respective images of the conductive pattern and a through hole are photoelectrically read with an image reader (20). The conductive pattern image is magnified in size to obtain a magnified pattern image (PIm), while the hole image is magnified at different magnification factors to obtain magnified hole images (HIn, HIn-i). A ring image (RP) is defined by the difference of the magnified hole images. The overlapped region (WR) on which the ring image and the magnified pattern image overlap each other is then calculated, and a defect or an opening of the conductive pattern is detected by calculating the aperture angle (θ) of the overlapped image.
52 Citations
18 Claims
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1. A method of inspecting a printed board for pattern defects, said printed board being provided with an electrically-conductive pattern and a through hole thereon, said method comprising the steps of:
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(a) photoelectrically reading an image of said printed board; (b) dividing said image of said printed board into a pattern image representing said conductive pattern and a hole image representing said through hole; (c) obtaining first and second images by selectively performing one of the steps of; (c-1) obtaining said first image by magnifying said pattern image and defining said second image with said hole image itself; (c-2) defining said first image with said pattern image itself and obtaining said second image by magnifying said hole image; and (c-3) obtaining said first and second images by magnifying said pattern image and said hole image, respectively; (d) detecting positional relation between said first and second images and representing said positional relation with a parameter value; and (e) comparing said parameter value with a predetermined reference value and thereby judging whether said conductive pattern has a non-allowable defect or not. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. An apparatus for inspecting a printed board for pattern defects, said printed board being provided with an electrically-conductive pattern and a through hole thereon, said apparatus comprising:
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(a) image reader means for photoelectrically reading an image of said printed board; (b) means for dividing said image of said printed board into a pattern image representing said conductive pattern and a hole image representing said through hold; (c) means for obtaining first and second images as a function of said pattern image and said hole image, respectively, where at least one of said first and second images is magnified in size as compared with corresponding one of said pattern image and said hole image; (d) means for detecting positional relation between said first and second images and representing said positional relation with a parameter value; and (e) means for comparing said parameter value with a predetermined reference value and thereby judging whether said conductive pattern has a non-allowable defect or not.
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Specification