HIGH DENSITY FLEX CONNECTOR SYSTEM

Abstract: Photodefined guide arrangements (24,26) on a connector (12) and a printed wiring board (10) are used to obtain an alignment between the connector (12) and the printed wiring board (10). A clamp fixed to the connector housing squeezes the connector contact fingers (22) to the connector pads (20) of the board to engage pads (20) and fingers (22) which have been guided into an overlapping position by the guide arrangements (24,26).

Description: This invention is directed to the alignment of a connector to a printed wiring board (PWB). The preparation and alignment of connectors to a PWB has been generally carried out by a complex, exacting process using the PWB edges for positioning the connector fingers relative to the PWB contact pads. The known positioning systems are not capable of positioning connector on centers of much less than 50 mils. This invention has been developed for reducing the complexity and increasing the reliability of the alignment of such connections. The invention provides an assembly capable of accurately aligning the connector fingers of a high density flex connector system with pads of a printed wiring board. GB 2059187 discloses an apparatus for connecting arrays of electrical conductors arranged on corresponding substrates including a clamp for squeezing the connector parts together and a means for facilitating the alignment of the arrays of conductors. The present invention is characterised in having an alignment means comprising a photodefined first and second guides located at each side of the array of pads and fingers, respectively, said first and second guides being shaped such that, as said connector fingers are guided into said overlapping position by longitudinal movement in the plane of contact between the connector and printed wiring board, the first and second guides interengage to laterally guide and align said fingers with said pads into a precisely aligned position from non-aligned positions. Preferably meshing guides located slightly ahead of said first and second guides and with greater longitudinal and lateral travel during meshing than the first and second guides are provided to provide a coarse alignment prior to engaging of the first and second guides. Fig. 1 is a perspective view of a connecting device that utilizes the invention. Fig. 2 is a sectioned view of the device of Fig.1 with the pivoting levers open taken along line 2-2. Fig. 3 is a sectioned view of Fig. 1 taken along line 3-3. Fig. 4 is an enlarged view of a portion of Fig. 3. Fig. 5 is an enlarged partial plan view of the overlap connection between the PWB and the flex connector. Fig. 6 is an enlarged partial view of Fig. 5. Referring now to Fig. 1, the embodiment chosen for purposes of illustration includes a printed wiring board 10 and a flex connector 12 joined together in an overlapping relationship within clamping connector housing 14. The overlapping relationship is best shown in Figs. 2, 5 and 6 wherein PWB 10 and flex connector 12 have photodefined traces 16, 18 respectively applied to opposed surfaces 16 a , 18 a in a manner well known in the art. The traces 16 terminate in an array of connector pads 20 while the traces 18 terminate in an array of fingers 22. The means for aligning the PWB with the flex connector includes guide arrangements attached both to the PWB and the flex connector. More particularly, referring to Fig. 5,vee-shaped first guides 26 are located at each side of the array of connector pads 20 on PWB 10 and wedge -shaped second guides 24 are located at each side of the array of fingers 22 of the flex connector 12. The guides 24, 26 are photodefined at the time the trades, pads and fingers are photodefined, i.e., all in one operation. In addition to guides 24, 26 slotted third guides 28 are located at each side of the array of fingers 22 on the flex connector 12 at its leading edge 12 a . These guides 28 have a slot 28 a in them to accept an alignment pin 30 mounted at each side of the array of pads 20 on PWB 10. The guides 28 are photodefined on connector 12 while pins 30 are made of steel and are inserted in holes on PWB 10. Guides 28 and pins 30 form a coarse alignment arrangement to bring guides 24, 26 to approximate alignment before they mesh to provide precise alignment of the fingers 22 with the pads 20. Since the pads and fingers overlap, the guides 24, 26 are plated to a thickness of the overlap so they will engage as the PWB overlaps the flex connector in housing 14 (See Fig.4). Electrical traces 31,32 located on flex connector 12 and PWB 10 respectively provide an electrical path to the edges of the flex connector and PWB to enable electroplating up of the guides 24,26,28. In addition these traces provide vertical positioning of the flex connector relative to the PWB during the joining process so that the fingers 22 properly overlap the pads 20. The housing 14 is used to squeeze PWB 10 and flex connector 12 together to make contact between pads 20 and fingers 22. Flexible connector 12 enters housing 14 through a slot 15 in end wall 17 of the housing and is clamped in place by pivoting lever 19 which locks in place under a lip 21 of wall 17. The PWB enters housing 14 through a slot 23 in end wall 25 of the housing. Slot 23 has enlargements 27 to allow pins 30 on PWB 10 to pass through. When the PWB is in position overlapping connector 12 as shown with surfaces 16 a , 18 a facing each other, a pivoting lever 32 squeezes them together to make contact between the pads 20 and fingers 22. The lever locks in place under a lip 21 a of wall 25. Since the alignment guides 24, 26 and the traces with fingers and pads on the connector and PWB are photodefined in one operation, an absolute positioning reference system is established which permits positioning of connector pads on much closer centers on the PWB than previously possible.

Claims: An assembly for connecting a photodefined array of connector pads (20) on a printed wiring board (10) with a matching array of photodefined connector contact fingers (22) of a high density flex connector system (12) including said printed wiring board (10) and connector system (12) and a clamp (14) for squeezing the connector (12) into contact with the printed wiring board (10) and a means for aligning said contact fingers (22) with said pads (20) as the connector contact fingers (22) are guided into an overlapping position with said pads (20) within said clamp (14) characterised by said alignment means comprising: a photodefined first guide (26) located at each side of the array of connector pads (20); and a photodefined second guide (24) located at each side of the array of fingers (22), said first (26) and second (24) guides being shaped such that, as said connector fingers (22) are guided into said overlapping position by longitudinal movement in the plane of contact between the connector (12) and printed wiring board (10), the first (26) and second (24) guides interengage to laterally guide and align said fingers (22) with said pads (20) into a precisely aligned position from non-aligned positions. The assembly of Claim 1 wherein said first guides (26) are shaped like a vee-block and said second guides (24) are shaped like a wedge to fit to together with the vee-block. The assembly of Claim 1 or 2, including a third slotted guide (28a) located at the leading edge of the connector (12) at each side of the array of fingers (22) and a pin (30) mounted on said printed wiring board (10) on each side of the array of said pads (20), said pins (30) engaging said slotted guides (28a) to approximately align said first (26) and second (24) guides. The assembly of Claim 3 wherein said third guide (28a) is photodefined on said connector (12).

Inventors: ELCO, RICHARD ALVA, VANDEGRIFF, HUGH RIEGEL
Applicants: E.I. DU PONT DE NEMOURS AND COMPANY
Application year: 1987
Main classification: H01R9
IPC codes: H01R12, H05K1, H05K3