Patent EP0390110A2 successfully refreshed from Google Patents.
EP0390110A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Method of and apparatus for inspecting conductive pattern on printed board
Assignee: Dainippon Screen Manufacturing Co Ltd
•
Filing: 1990-03-28
•
Granted: —
•
Expires: 2010-03-28
Abstract
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 (PI m ), while the hole image is magnified at different magnification factors to obtain magnified hole images (HI n , HI n-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.
Inventors
- 👤 Ryuji C/O Dainippon Screen Mfg. Co. Ltd Kitakado
- 👤 Hironobu C/O Dainippon Screen Mfg. Co. Ltd. Yano
- 👤 Hiroaki C/O Dainippon Screen Mfg. Co. Ltd Kakuma
- 👤 Tetsuo C/O Dainippon Screen Mfg. Co. Ltd. Hoki
- 👤 Takao C/O Dainippon Screen Mfg. Co. Ltd. Kanai
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 17:08
CPC Classifications
H; H05; H05K; H05K13/00; H05K13/08; G; G06; G06T; G06T7/00; G06T7/0002; G06T7/0004; G06T7/0006; H05K13/06; G06T2207/00; G06T2207/30; G06T2207/30108; G06T2207/30141
Claims Analysis
Total Claims: 32
Claim 1
Independent Claim
178 words
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.
Claim 2
Independent Claim
178 words
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.
Claim 3
Dependent Claim
57 words
A method of claim 1, wherein; the step (c-3) includes the steps of: (c-3-1) magnifying said pattern image and thereby obtaining said first image; and (c-3-2) magnifying said hole image at different two magnification factors and thereby obtaining first and second magnified hole images, respectively, said second image consisting of said first and second magnified hole images.
Claim 4
Dependent Claim
57 words
A method of claim 2, wherein: the step (d) includes the steps of: (d-1) calculating a difference between said first and second magnified hole images and thereby obtaining a ring image; and (d-2) comparing said first image with said ring image to detect said positional relation and determining said parameter value in accordance with said positional relation.
Claim 5
Dependent Claim
51 words
A method of claim 3, wherein: the step (d-2) includes the steps of: (d-2-1) obtaining an overlapped region image representing an overlapped region on which said first image and said ring image overlap each other; and (d-2-2) comparing said overlapped region image with said ring image to detect said positional relation.
Claim 6
Dependent Claim
71 words
A method of claim 4, wherein: the step (d-2-2) includes the steps of: (d-2-3) counting a first number of pixels included in said overlapped region image; and (d-2-4) counting a second number of pixels included in said ring image, said parameter value including said first and second numbers; said method further including the step of: (d-3) comparing a ratio of said first number to said second number with said reference value.
Claim 7
Dependent Claim
46 words
A method of claim 5, wherein: the step (d-3) includes the steps of: (d-3-1) multiplying said second number by said reference value to obtain a reference pixel number, said reference value being smaller than one; and (d-3-2) comparing said first number with said reference pixel number.
Claim 8
Dependent Claim
68 words
A method of claim 4, wherein: the step (d-2-2) includes the steps of: (d-2-3) obtaining a first position representing a location of said ring image on an image plane; (d-2-4) obtaining a second position representing a location of said overlapped region image on said image plane; and (d-2-5) calculating a distance between said first and second positions and determining said parameter value as a function of said distance.
Claim 9
Dependent Claim
46 words
A method of claim 7, wherein: the step (d-2-3) includes the step of: calculating a center position of said ring image as said first position; and the step (d-2-4) includes the step of: calculating a center-of-mass position of said overlapped region image as said second position.
Claim 10
Dependent Claim
46 words
A method of claim 7, wherein: the step (d-2-3) includes the step of: calculating a center-of-mass position of said ring image as said first position; and the step (d-2-4) includes the step of: calculating a center-of-mass position of said overlapped region image as said second position.
Claim 11
Dependent Claim
31 words
A method of claim 4, further comprising the step of: (f) detecting a center position of said hole image to specify a location of said non-allowable defect on said printed board.
Claim 12
Dependent Claim
160 words
A method of claim 10, wherein: the step (f) includes the steps of: (f-1) providing an assumed center line to said first magnified hole image and dividing said first magnified hole image into first and second parts with said assumed center line, said assumed center line crossing a contour of said first magnified hole image at two points; (f-2) counting respective areas of said first and second parts within a range between said two points; (f-3) calculating a difference between said respective areas; (f-4) comparing said difference between said respective areas with a predetermined threshold value; (f-5) repeating the steps (f-1) through (f-4) while relatively moving said assumed center line and said first magnified hole image until said difference between said respective areas becomes smaller than said threshold value; and (f-6) determining said center position of said hole image as a function of said assumed center line when said difference between said respective areas becomes smaller than said threshold value.
Claim 13
Dependent Claim
32 words
A method of claim 11, wherein: the step (f-6) includes the step of: (f-6-1) calculating a center point between said two points and thereby obtaining said center position of said hole image.
Claim 14
Dependent Claim
127 words
A method of claim 12, wherein: the step (d-2-2) includes the step of: (d-2-3) comparing said overlapped region image with said ring image within said range between said two points and generating said parameter value while relatively moving said assumed center line and said first magnified hole image; and the step (e) includes the step of: (e-1) comparing said parameter value with said reference value and obtaining a result of a judgement regarding whether said conductive pattern has a non-allowable defect or not every time it is concluded that said difference between said respective ares is smaller than said threshold value, whereby a plurality of results of said judgement are obtained; and (e-2) selecting one result from said plurality of results according to a predetermined selection rule.
Claim 15
Dependent Claim
160 words
A method of claim 1 wherein: the step (d) includes the steps of: (d-1) obtaining a center line of said second image; (d-2) defining a reference point on said center line; (d-3) calculating a first distance from said reference point to a contour of said first image as measured in a reference direction which is not in parallel to said center line; (d-4) calculating a second distance from said reference point to a contour of said second image as measured in said reference direction; (d-5) comparing said first and second distances with each other; (d-6) repeating the steps (d-2) through (d-5) while changing a position of said reference point on said center line, whereby a plurality of comparison results are obtained in the step (d-5); (d-7) calculating a length of a break in said conductive pattern as a function of said plurality of comparison results; and (d-8) determining said parameter value as a function of said length of said break.
Claim 16
Dependent Claim
142 words
A method of claim 14, wherein: the step (d-1) includes the steps of: (d-1-1) providing an image plane on which said first and second images are defined; and (d-1-2) dividing said image plane into first and second partial planes by said center line; the step (d-6) includes the step of: (d-6-1) performing the steps (d-2) through (d-5) on each of said first and second partial planes and thereby obtaining said plurality of comparison results for each of said first and second partial planes; the step (d-7) includes the step of: (d-7-1) calculating said length of said break on each of said first and second partial planes; and the step (d-8) includes the step of: (d-8-1) summing up respective length of said break on said first and second partial planes and determining said parameter value as a function of a summation thus obtained.
Claim 17
Dependent Claim
40 words
A method of claim 15, wherein: the step (d-8-1) includes the steps of: (d-8-2) calculating a circumference of said second image; and (d-8-3) calculating a ratio of said summation to said circumference of said second image as said parameter value.
Claim 18
Dependent Claim
38 words
A method of claim 16, wherein: the step (d-8-2) includes the steps of: defining a square circumscribing said second image; and calculating a circumference of said square as an approximate value of said circumference of said second image.
Claim 19
Independent Claim
264 words
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) obtaining an overlapped region image representing an overlapped region on which said first and second images overlap each other; (e) defining a two-dimensional radial operator having unit operators which extend from a radiant center point to different directions; (f) detecting end points of said overlapped region image by applying said radial operator to said overlapped region image while relatively moving said radial operator and said overlapped region image; (g) detecting a center point of said second image; (h) calculating an aperture angle of said conductive pattern as a function of positional relation between said end points and said center point of said second image; and (i) comparing said aperture angle with a predetermined reference angle and thereby judging whether said conductive pattern has a non-allowable defect or not.
Claim 20
Independent Claim
264 words
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) obtaining an overlapped region image representing an overlapped region on which said first and second images overlap each other; (e) defining a two-dimensional radial operator having unit operators which extend from a radiant center point to different directions; (f) detecting end points of said overlapped region image by applying said radial operator to said overlapped region image while relatively moving said radial operator and said overlapped region image; (g) detecting a center point of said second image; (h) calculating an aperture angle of said conductive pattern as a function of positional relation between said end points and said center point of said second image; and (i) comparing said aperture angle with a predetermined reference angle and thereby judging whether said conductive pattern has a non-allowable defect or not.
Claim 21
Dependent Claim
102 words
A method of claim 18, wherein: each of the steps (c-2) and (c-3) includes the step of magnifying said hole image at different two magnification factors and thereby obtaining first and second magnified hole images, respectively, said second image consisting of said first and second magnified hole images; and the step (d) includes the steps of: (d-1) calculating a difference between said first and second magnified hole images and thereby obtaining a ring image; and (d-2) generating an image which represents a region on which said first image and said ring image overlap each other, whereby said overlapped region image is obtained.
Claim 22
Dependent Claim
150 words
A method of claim 18, wherein: the step (f) includes the steps of: (f-1) obtaining a logical pattern in which a result of applying said radial operator to said overlapped region image is represented by a radial arrangement of arms each of which is a chain of bits being at first and/or second logical levels; (f-2) within said arms, detecting a first arm only including said first logical level and a detecting a second arm including said firstd logical level at only one bit, said second arm extending in a direction reverse to said first arm; (f-3) identifying one of said end points by a current position of said radiant center point at which both of said first and second arms are detected; and (f-4) repeating the steps (f-2) and (f-3) while relatively moving said radial operator and said overlapped region image until all of said end points are identified.
Claim 23
Independent Claim
238 words
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 first pattern image representing said conductive pattern and a hole image representing said through hole; (c) obtaining a second pattern image by selectively performing one of the steps of: (c-1) defining said second pattern image by said first pattern image itself; and (c-2) magnifying said hole image to obtain a magnified hole image and then obtaining said second pattern image by an overlapped region image representing an overlapped region on which said first pattern image and said magnified hole image overlap each other; (d) detecting a center point of said hole image; (e) defining a two-dimensional radial operator having unit operators which extend from a radial center point to different directions; (f) applying said radial operator to said second pattern image under the condition where said radiant center point is positioned at said center point of said hole image; (g) calculating an aperture angle of said second pattern image as a function of an application result of said radial operator obtained in the step (f); and (h) comparing said aperture angle with a predetermined reference angle and thereby judging whether said conductive pattern has a non-allowable defect or not.
Claim 24
Independent Claim
238 words
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 first pattern image representing said conductive pattern and a hole image representing said through hole; (c) obtaining a second pattern image by selectively performing one of the steps of: (c-1) defining said second pattern image by said first pattern image itself; and (c-2) magnifying said hole image to obtain a magnified hole image and then obtaining said second pattern image by an overlapped region image representing an overlapped region on which said first pattern image and said magnified hole image overlap each other; (d) detecting a center point of said hole image; (e) defining a two-dimensional radial operator having unit operators which extend from a radial center point to different directions; (f) applying said radial operator to said second pattern image under the condition where said radiant center point is positioned at said center point of said hole image; (g) calculating an aperture angle of said second pattern image as a function of an application result of said radial operator obtained in the step (f); and (h) comparing said aperture angle with a predetermined reference angle and thereby judging whether said conductive pattern has a non-allowable defect or not.
Claim 25
Dependent Claim
83 words
A method of claim 21, wherein: said radial operator is a logical gate operator; the step (g) includes the steps of: (g-1) obtaining a logical pattern in which said application result is represented by a radial arrangement of arms each of which is a chain of bits being at first and/or second logical levels; and (g-2) counting a number of said arms only including said first logical level and then obtaining said aperture angle as a function of said number of said arms.
Claim 26
Dependent Claim
55 words
A method of claim 22, further comprising the steps of: (i) detecting a size of said hole image; (j) compressing said second pattern image at a compression ratio which is selected as a function of said size and thereby obtaining a compressed image which is employed in the step (f) as said second pattern image.
Claim 27
Independent Claim
160 words
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: (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 hole; (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.
Claim 28
Independent Claim
160 words
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: (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 hole; (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.
Claim 29
Independent Claim
263 words
An apparatus for inspecting a printed board for pattern defects, said printed board being provided with an electrically-conductive pattern and a through hole therein, said apparatus comprising: (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 hole; (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 obtaining an overlapped region image representing an overlapped region on which said first and second images overlap each other; (e) logic circuit means for defining a two- dimensional radial operator having unit operators which extend from a radiant center point to different directions; (f) means for serially supplying respective parts of said overlapped region image to said logic circuit means; (g) means for detecting end points of said overlapped image as a function of output signals of said logic circuit means; (h) means for detecting a center point of said second image; (i) means for calculating an aperture angle of said conductive pattern as a function of positional relation between said end points and said center point of said second image; and (j) means for comparing said aperture angle with a predetermined reference angle and thereby judging whether said conductive pattern has a non-allowable defect or not.
Claim 30
Independent Claim
263 words
An apparatus for inspecting a printed board for pattern defects, said printed board being provided with an electrically-conductive pattern and a through hole therein, said apparatus comprising: (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 hole; (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 obtaining an overlapped region image representing an overlapped region on which said first and second images overlap each other; (e) logic circuit means for defining a two- dimensional radial operator having unit operators which extend from a radiant center point to different directions; (f) means for serially supplying respective parts of said overlapped region image to said logic circuit means; (g) means for detecting end points of said overlapped image as a function of output signals of said logic circuit means; (h) means for detecting a center point of said second image; (i) means for calculating an aperture angle of said conductive pattern as a function of positional relation between said end points and said center point of said second image; and (j) means for comparing said aperture angle with a predetermined reference angle and thereby judging whether said conductive pattern has a non-allowable defect or not.
Claim 31
Independent Claim
215 words
An apparatus for inspecting a printed board for pattern defects, said printed board being provided with an electrically-conductive pattern and a through hole therein, said apparatus comprising: (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 hole; (c) means for magnifying said hole image and thereby obtaining a magnified hole image; (d) means for obtaining an overlapped region image representing an overlapped region on which said pattern image and said magnified hole image overlap each other; (e) means for detecting a center point of said hole image; (f) logic circuit means for defining a two-dimensional radial operator having unit operators which extend from a radial center point to different directions; (f) means for supplying said overlapped image to said logic circuit means such that said radiant center point is positioned at said center point of said hole image; (g) means for calculating an aperture angle of said overlapped region image as a function of outputs of said logic circuit means; and (h) means for comparing said aperture angle with a predetermined reference angle and thereby judging whether said conductive pattern has a non-allowable defect or not.
Claim 32
Independent Claim
215 words
An apparatus for inspecting a printed board for pattern defects, said printed board being provided with an electrically-conductive pattern and a through hole therein, said apparatus comprising: (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 hole; (c) means for magnifying said hole image and thereby obtaining a magnified hole image; (d) means for obtaining an overlapped region image representing an overlapped region on which said pattern image and said magnified hole image overlap each other; (e) means for detecting a center point of said hole image; (f) logic circuit means for defining a two-dimensional radial operator having unit operators which extend from a radial center point to different directions; (f) means for supplying said overlapped image to said logic circuit means such that said radiant center point is positioned at said center point of said hole image; (g) means for calculating an aperture angle of said overlapped region image as a function of outputs of said logic circuit means; and (h) means for comparing said aperture angle with a predetermined reference angle and thereby judging whether said conductive pattern has a non-allowable defect or not.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.