Electrical connectors – Including elastomeric or nonmetallic conductive portion – Adapted to be sandwiched between preformed panel circuit...
Reexamination Certificate
1999-06-17
2001-12-18
Gaffin, Jeffrey (Department: 2841)
Electrical connectors
Including elastomeric or nonmetallic conductive portion
Adapted to be sandwiched between preformed panel circuit...
C174S251000, C174S261000, C361S767000, C361S792000
Reexamination Certificate
active
06331118
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an electrode spacing conversion adaptor to be used to properly connect test points on a fine-pitch conductor pattern of a printed wiring board to external test equipment for automatic board testing.
2. Discussion of the Related Art
For automatic testing of a conductor side of a printed wiring board, it has conventionally been required to connect one or more pairs of test points on the conductor side to an external board tester by using a pair of contact probes.
Each contact probe includes a sleeve and a contact pin which is slidably housed in the sleeve and forced toward a far end of the sleeve by a spring fitted in the sleeve. A lead connected to the contact pin emerges from inside the sleeve for external connection. A pair of such spring contact probes directed to the conductor side of the printed wiring board are moved to desired test points and brought into contact therewith, and connections between the test points and the external board tester are established.
With printed circuit conductor patterns becoming more and more finely pitched nowadays, a problem often encountered with contact probe technique of the prior art has been that the contact pins of two probes tend to contact each other when probing nearby test points, making it impossible to properly perform the board testing.
SUMMARY OF THE INVENTION
In view of the aforementioned problem of the prior art, it is an object of the invention to provide an electrode spacing conversion adaptor which facilitates automatic testing of a printed wiring board carrying a fine-pitch conductor pattern. It is a more specific object of the invention to provide an electrode spacing conversion adaptor which is formed by laminating a plurality of angled sheet elements and carries electrodes arranged with different spacings on top and bottom surfaces of the adaptor so that electrical connections can be easily established from nearby test points on a fine-pitch conductor pattern of a printed wiring board to external test equipment.
According to a main feature of the invention, an electrode spacing conversion adaptor is formed of a plurality of sheet elements having top and bottom electrodes arrayed at different intervals along upper and lower ends of each sheet element, respectively, wherein the top electrodes are individually connected to their corresponding bottom electrodes by conductors, and the individual sheet elements are angled in such a way that the upper portions carrying the top electrodes are stacked in the direction of the thickness of the sheet elements at intervals different from intervals at which the lower portions carrying the bottom electrodes are stacked.
Since the top and bottom electrodes are arrayed at different intervals and the sheet elements are angled such that the upper portions carrying the top electrodes and the lower portions carrying the bottom electrodes can be stacked at different intervals in the direction of their thickness in this construction, the top electrodes are arranged at intervals different from the intervals at which the bottom electrodes are arranged in two horizontal directions when the sheet elements are stacked to form a single structure. More specifically, the sheet elements can be stacked in such a way that the bottom electrodes are arrayed at small intervals and the top electrodes are arranged at large intervals, for example. When the bottom electrodes of the electrode spacing conversion adaptor of this example are positioned in close contact with a conductor pattern of a printed wiring board, test points on the conductor pattern electrically connected to the corresponding top electrodes. Even when individual conductors of the conductor pattern are finely pitched, the geometric arrangement of the test points is enlarged at the top electrodes. This electrode spacing conversion feature of the adaptor makes it easier to connect the printed wiring board to external measuring equipment or to matrix circuit devices for electrical testing between specified test points.
In one aspect of the invention, the thickness of the upper portion of each sheet element carrying the top electrodes may be made different from the thickness of the lower portion of each sheet element carrying the bottom electrodes.
If the upper portion of each sheet element is formed to a thickness larger than that of the lower portion, for example, the top electrodes can be arranged at larger intervals than the bottom electrodes in the stacking direction of the individual sheet elements, without using any specially made spacers.
According to the invention, the electrode spacing conversion adaptor may be produced by laminating the sheet elements into a single laminated piece, or by laminating the sheet elements into a plurality of laminated pieces and further laminating the laminated pieces together with spacers to form a plurality of laminar blocks which can be assembled into a single structure.
The electrode spacing conversion feature can be achieved with each laminated piece regardless of whether it is produced by laminating the sheet elements alone or by laminating the sheet elements together with the spacers to obtain convenient shapes. If a plurality of laminar blocks produced by laminating a plurality of laminated pieces together with the spacers are assembled to form a large-sized boxlike shape, for example, it is possible gather the bottom electrodes arranged at small intervals in a central area of a bottom surface of the electrode spacing conversion adaptor and distribute the top electrodes arranged at large intervals in a broader top surface area of the electrode spacing conversion adaptor.
In another aspect of the invention, the electrodes arrayed at greater intervals may be clustered to form a specified number of electrode groups.
In this construction, the electrodes distributed in the individual electrode groups can be arrayed such that the electrode groups correspond to the individual matrix circuit devices without providing an additional fixture between the electrode spacing conversion adaptor and the matrix circuit devices.
In a further aspect of the invention, an insulating sheet may placed on one side of each sheet element to cover one side of the conductors which are exposed on both sides of each sheet element. The conductors and the remaining part of each sheet element may be made of an electrically conductive rubber material and an electrically nonconductive rubber material, respectively.
In this construction, conductors exposed on one side of the each successive sheet element can be insulated and, therefore, it is not necessary to apply a dielectric coating on each sheet element before laminating the sheet elements.
These and other objects, features and advantages of the invention will become more apparent upon reading the following detailed description in conjunction with the accompanying drawings.
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patent: 2276502 (1994-09-01), None
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Hirano Masanori
Ono Hiroaki
Alcala Jose' H.
Gaffin Jeffrey
Kabushiki Kaisha Linear Circuit
Smith Patent Office
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