Method and apparatus for visually examining an array of objects disposed in a narrow gap
First Claim
1. A method for visually examining a plurality of objects disposed to extend transversely of a gap approximately 1.5 mm defined between first and second generally parallel, spaced plates having respective, substantially flat inner surfaces facing the gap, the first plate being light transmissible and having an outer surface generally parallel to the inner surface thereof, comprising the steps of:
- illuminating the outer surface of the first plate to produce diffused light within the gap which illuminates the objects and is emitted from an edge of the gap,deflecting the light emitted from the edge of the gap in a direction substantially perpendicular to the inner surface of the first plate; and
focusing the emitted light to form an image of a selected number of the objects.
1 Assignment
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Accused Products
Abstract
A method of and apparatus for visual inspection of the condition of soldered connections between connector pads of a wiring pattern provided on a circuit board and tips of conductor pins of an IC package mounted thereby on the circuit board. The back, or bottom surface of the circuit board is illuminated by a flood of light to produce diffused, or scattered, light in the gap between the circuit board and the IC package, which diffused light is emitted from the edge of the gap. The emitted light is deflected by a small prism disposed adjacent the edge of the gap into a focusing means, such as a stereoscopic microscope having a long focal distance and an optical axis oriented substantially perpendicularly to the surface of the circuit board. Images of the soldered connections are observeable through the eyepiece of the microscope, or are detected by a photoelectric transducer such as a video camera for display on a video screen.
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Citations
21 Claims
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1. A method for visually examining a plurality of objects disposed to extend transversely of a gap approximately 1.5 mm defined between first and second generally parallel, spaced plates having respective, substantially flat inner surfaces facing the gap, the first plate being light transmissible and having an outer surface generally parallel to the inner surface thereof, comprising the steps of:
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illuminating the outer surface of the first plate to produce diffused light within the gap which illuminates the objects and is emitted from an edge of the gap, deflecting the light emitted from the edge of the gap in a direction substantially perpendicular to the inner surface of the first plate; and focusing the emitted light to form an image of a selected number of the objects. - View Dependent Claims (2, 3, 4)
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5. An apparatus for visually examining a plurality of objects disposed to extend transversely of a gap approximately 1.5 mm defined between first and second, generally parallel, spaced plates having respective, substantially flat inner surfaces facing the gap, the first plate being light transmissible and having an outer surface generally parallel to the inner surface thereof, comprising:
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means for illuminating the outer surface of the first plate to produce diffused light within the gap which illuminates the objects and is emitted from an edge of the gap; means for deflecting the light emitted from the edge of the gap in a direction substantially perpendicular to the inner surface of the first plate; and means for focusing the emitted light to form an image of a selected number of the objects. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12)
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13. Apparatus for visually examining soldered connections formed between conductor leads of an integrated circuit package and corresponding connector pads of a printed circuit board, wherein the respective, opposing surfaces of the integrated circuit package and the printed circuit board are substantially flat and spaced apart to define a gap therebetween, the printed circuit board is light transmissible and has an outer surface generally parallel to the inner surface thereof, the conductor leads extend transversely across the gap from the inner surface of the integrated circuit package, and the connector pads are formed on the inner surface of the printed circuit board in positions corresponding to the conductor leads, comprising:
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means for supporting a printed circuit board having an integrated circuit package mounted thereon, with the inner surfaces of the package and the printed circuit board parallel to a first plane; means for illuminating the outer surface of the printed circuit board to produce diffused light within the gap, which illuminates the soldered connections and is emitted from an edge of the gap; first deflecting means selectively positionable in a plane parallel to said first plane and adjacent the inner surface of a printed circuit board, so as to receive light emitted from the gap and to deflect same in a direction substantially perpendicular to said first plane; and means for receiving and focusing said light transmitted in said substantially perpendicular direction, for forming an image of the soldered connections between the corresponding conductor leads and pads. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21)
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Specification