EP0149849A2
Expired / Lapsed
EP
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Pattern detecting apparatus
Assignee: Hitachi Ltd
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Filing: 1984-12-27
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Granted: —
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Expires: 2004-12-27
Abstract
Abstract A pattern detecting apparatus for inspecting a printed wiring board is disclosed in which a fluorescent image formed by the fluorescent light from the substrate of the printed wiring board and an image formed by the reflected light from the wiring pattern of the printed wiring board are both used because a wiring material which is left on an undesired portion of the substrate and has low reflectivity, is detected only at the fluorescent image and a defective portion (6) of the wiring pattern where a surface layer thereof peels off, is detected only at the image formed by the reflected light, the image used for detecting the above defective portion is preferably formed by the reflected infrared light from the wiring pattern for the reason that infrared light is insensitive to a shallow flaw (7) in the surface of the wiring pattern, and the fluorescent image and the infrared image are processed by a detection circuit, and then compared with each other to detect a pattern defect on the basis of a difference between the images thus processed.
Inventors
- 👤 Yasuhiko Hara
- 👤 Koichi Karasaki
- 👤 Noriaki Ujiie
- 👤 Akira Sase
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 09:38
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/84; G01N21/88; G01N21/95; G01N21/956; G01N21/17; G01N21/25; G01N21/31; G01N21/35; G01N21/62; G01N21/63; G01N21/64
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
165 words
A pattern detecting apparatus for inspecting a body which has a wiring pattern on a material capable of generating fluorescent light, comprising: a light source (11, 12, 16) emitting both exciting light (32) for generating the fluorescent light and separable light from said exciting light for producing reflected light (42) from the surface of the wiring pattern; a first mirror (17) for leading light from said light source, to the to-be-inspected body; a filter (18) for transmitting said fluorescent light from said to-be-inspected body and said reflected light from said to-be-inspected body, and for removing said exciting light reflected from said to-be-inspected body; an optical system including a lens (14) and a second mirror (20, 21) for focussing said fluorescent light and said reflected light on a fluorescent-light detector (19) and a reflected-light detector (15'), respectively; and a detection circuit (55, 57; 60, 62; 156, 159, 160, 162, 163) having functions of contracting, enlarging, masking and combining pattern images which are detected by said detectors.
Claim 2
Dependent Claim
165 words
A pattern detecting apparatus for inspecting a body which has a wiring pattern on a material capable of generating fluorescent light, comprising: a light source (11, 12, 16) emitting both exciting light (32) for generating the fluorescent light and separable light from said exciting light for producing reflected light (42) from the surface of the wiring pattern; a first mirror (17) for leading light from said light source, to the to-be-inspected body; a filter (18) for transmitting said fluorescent light from said to-be-inspected body and said reflected light from said to-be-inspected body, and for removing said exciting light reflected from said to-be-inspected body; an optical system including a lens (14) and a second mirror (20, 21) for focussing said fluorescent light and said reflected light on a fluorescent-light detector (19) and a reflected-light detector (15'), respectively; and a detection circuit (55, 57; 60, 62; 156, 159, 160, 162, 163) having functions of contracting, enlarging, masking and combining pattern images which are detected by said detectors.
Claim 3
Dependent Claim
35 words
A pattern detecting apparatus according to Claim 1, whrein said first mirror (17) is a dichroic mirror which reflects said exciting light and transmits said fluorescent light and said reflected light from said to-be-inspected body.
Claim 4
Dependent Claim
62 words
A pattern detecting apparatus according to Claim 2, wherein said first mirror (17) is placed substantially at 45° inclined to a light beam emitted from said light source (11). 4. A pattern detecting apparatus according to Claim 1, wherein said second mirror is an infrared reflecting mirror (20) which transmits said fluorescent light and reflects said reflected light from said to-be-inspected body.
Claim 5
Dependent Claim
25 words
A pattern detecting apparatus according to Claim 4, wherein said second mirror is placed substantially at 45° inclined to the optical axis of said lens.
Claim 6
Dependent Claim
26 words
A pattern detecting apparatus according to Claim 4, wherein said infrared refecting mirror has practical transmittance for light having a wavelength of 400 to 700 nm.
Claim 7
Dependent Claim
31 words
A pattern detecting apparatus according to Claim 1, wherein said second mirror is a cold mirror (21) which reflects said fluorescent light and transmits said reflected light from said to-be-inspected body.
Claim 8
Dependent Claim
25 words
A pattern detecting apparatus according to Claim 7, wherein said second mirror is placed substantially at 45° inclined to the optical axis of said lens.
Claim 9
Dependent Claim
24 words
A pattern detecting apparatus according to Claim 7, wherein said cold mirror (21) practically reflects light having a wavelength of 450 to 650 nm.
Claim 10
Dependent Claim
108 words
A pattern detecting apparatus according to Claim 1, wherein said detection circuit is operated in such a manner that a signal (71) from said fluorescent-light detector (19) is subjected to analog-to-digital conversion and then converted into a binary signal, an image formed by said binary signal is inverted in polarity and contracted to form a polarity-inverted, contracted fluorescent image, a signal (81) from said reflection-light detector (15') is subjected to analog-to-digital conversion and then converted into a digital signal, to form an image based upon said reflected light, and said image based upon said reflected light is masked by said polarity-inverted, contracted fluorescent image, to detect a defect.
Claim 11
Dependent Claim
108 words
A pattern detecting apparatus according to Claim 10, wherein said detection circuit is operated in such a manner that said signal (71) from said fluorescent-light detector (19) is subjected to analog-to-digital conversion and then converted into said binary signal, said image formed by said binary signal is contracted so that the image of said wiring pattern is extinguished, and then enlarged so that the remainder image of a pattern is returned to an original size, and the image having been subjected to the contraction and enlargement processing is used for masking said polarity-inverted, contracted fluorescent image and said image based upon said reflected light, to detect a defect.
Claim 12
Dependent Claim
102 words
A pattern detecting apparatus according to Claim 1, wherein said detection circuit is operated in such a manner that a signal (71) from said fluorescent-light detector (19) is subjected to analog-to-digital conversion and then converted into a binary signal, an image formed by said binary signal is contracted to form a contracted fluorescent image, a signal (81) from said reflected-light detector (15') is subjected to analog-to-digital conversion and then converted into a binary signal, to form an image based upon said reflected light, and said contracted fluorescent image is combined with said image based upon said reflected light, to detect a defect.
Claim 13
Dependent Claim
105 words
A pattern detecting aapparatus according to Claim 1, wherein said detection circuit is operated in such a manner that a signal (71) from said fluorescent-light detector (19) is subjected to analog-to-digital conversion and then converted into a binary signal, an image formed by said binary signal is contracted so that the image of said wiring pattern is extinguished, and then enlarged so that the remainder image of a pattern is returned to an original size, and the image having been subjected to the contraction and enlargement processing is used for masking images based upon said fluorescent light and said reflected light, to detect a defect.
Claim 14
Dependent Claim
53 words
A pattern detecting apparatus according to Claim 1, wherein said fluorescent-light detector (19) is one of an image pickup device having practical sensitivity for light within a wavelength range from 400 to 600 nm or an image pickup device having practical sensitivity for light within a wavelength range from 400 to 700 nm.
Claim 15
Dependent Claim
34 words
A pattern detecting apparatus according to Claim 1, wherein said reflected-light detector (15 1 ) is an image pickup device having practical sensitivity for light within a wavelength range from 400 to 1,000 nm.
References Cited (Backward Citations)
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