GB2027560A - Electrical connector - Google Patents

Abstract

An electrical connector assembly, for making connection with an LCD panel 11, comprises contacts 25 each formed as a pip in a conductor strip 26, moulded in a resilient elastomeric insulator 24. In its upper face the insulator has an aperture 28, closely surrounded by an annular upstanding sealing lip 29. The insulator 24 is received in a rigid base 14, having a support pip 34 underlying each contact 25. When the LCD is pressed towards the base 14 (by clamping means not shown), lip 29 is compressed to provide a seal around the electrical contact area, and the contact is resiliently urged against the LCD by the portion of elastomeric insulator between the contact 25 and the rigid pip 34. <IMAGE>

Description

SPECIFICATION Electrical connector One problem which arises with electrical connectors for electrically connecting two or more sets of electrical conductors, such as plug-in printed circuit board connectors, integrated circuit board connectors, liquid crystal display unit connectors and the like is that, if moisture and hostile atmosphere migrate between the contact surfaces, the quality and reliability of electrical contact rapidly deteriorates, particularly if expensive precious metal contacts are not used. The present invention is concerned with overcoming this problem.

The invention provides, in one of its aspects, an electrical connector for making electrical connection to a substantially rigid body, which electrical connector comprises: a a plurality of electrically conducting contacts; a resilient insulator overlying the contacts and having an aperture opposite each contact; the insulator having a sealing lip or rim surrounding each aperture; whereby when the connector is pressed against the body so that each contact connects to the body through its associated aperture, the sealing lip or rim surrounding that aperture forms a seal against the body and surrounding the contact.

The shape of the sealing lip may be preformed in the resilient insulator e.g. by moulding.

The resilient insulator may be moulded with the electrical contacts embedded therein.

Preferably the arrangement is such that the contact is urged towards the body by resilient means behind it, e.g. by part of the resilient insulator behind the contact.

Where the connector also comprises a substantial- ly rigid backing, preferably a projection or protruberance is provided thereon opposite each contact, to assist in resiliently urging the contact towards the body.

Preferably the relative arrangement of each contact with respect to the overlying resilient insulator is such that, before the resilient insulator is compressed against the body, each contact protrudes through its overlying aperture beyond the surface of the insulator, and the surrounding sealing lip is upstanding from the surface beyond the protruding contact.

The space within the sealing lip and overlying the contact may be filled with an inert substance such as paste or grease, to eliminate air or other gas from that space.

The invention includes a device comprising combination of an electrical connector as aforesaid with a substantially rigid mounttherefor. In one embodiment, the mount has a first part underlying the connector and a second part upstanding therefrom, at least one of the electrical contacts being formed as part of an elongated conductor which protrudes from the resilient insulator and extends through an aperture in the second part of the mount. Preferably the remote end of the elongated conductor is adapted to be connected to a further electrical component (e.g. a printed circuit board). Preferably such connection is also adapted to mechanically connect the component.

Preferably the device further comprises clamping means for pressing a substantially rigid body, to which electrical connection is to be made, against the electrical connector. The substantially rigid body is preferably thereby mounted on the device. Consequently, where the device is supported by a further electrical component as aforesaid, the body is thereby both mounted on, and electrically connected to, the further electrical component.

Preferably the device comprises the combination of two or more connectors as aforesaid with a common substantially rigid mount therefor.

The electrically conducting contact may be of beryllium copper. The resilient insulator may be an elastomer, for example, polyurethane or a silicone rubber.

A specific embodiment of the invention, in the form of a combined mounting and electrical connector device for a liquid crystal display (LCD) panel, will now be described by way of example and with reference to the accompanying drawings, in which :- Figure 1 is a perspective view of part of the assembly showing two adjacent contacts and their sealing lips; Figure 2 is a section through one of the contacts, before compression of the resilient insulator; Figure 3 is similar to Figure 2 but shows the position after compression against the LCD panel; and Figure 4 is a section through the complete assembly.

The LCD 11 (Figure 4) for use with which this device is designed is a rigid glass assembly about Scms long by 3cms wide by 0.2cms thick. A strip along each long side is of reduced thickness to provide mounting and contact flanges 12,13,the underside of each flange carrying twenty electrically conductive contact strips (e.g. metalised strips) spaced apart equally, along the length of the flange.

It is to these strips that the individual electrical connections have to be made.

The assembly comprises a rigid rectangular base frame 14 which, in this example, is madefrom an acetal homopolymer material available under the name DELRIN (R.T.M.). the base frame has a recess in its upper face, providing along each long side a first part underlying the connector in the form of an upwardly facing surface 15, 16, and, outside the latter, a second part in the form of an upstanding wall 17, 18. On each surface 15, 16 lies an elongated electrical connector 19, 21. The connectors 19, 21 are sandwiched between the underlying backing surface 15, 16 of the frame and the overlying flange 13, 12 of the LCD. The LCD is urged towards the base 14 by means of a bezel retainer 22.This is releasably secured to the frame by integral downwardly extending flanges 23 along its long sides, which are pushed through slots 32 in the base frame, outside the walls 17, 18. The bottom of each flange 23 has a barb-like bead 36 which engages the bottom edge of a rail 30 defining the outside of the slot 32. Engagement and disengagement are possible because of slight resilience in the flanges 23 and the rails 30 of the base frame.

The individual electrical contacts in each connector 19, 21 are arranged to connect with the twenty conductive strips on the LCD flange above it. As shown more clearly in Figures 1 and 2, the connector 19 comprises a resilient insulator in the form of an elongated strip 24 of polyurethane. Incorporated into the insulatorwhen it is formed by moulding are twenty contacts 25. Each contact is formed by a substantially part-spherical pip, deformed upwardly in an electrical conductor 26 comprising a strip of beryllium copper extending transversely across the insulator and embedded in it about half way down.

The upper face 27 of the insulator has a circular aperture 28 overlying the contact 25 through which the latter protrudes so that the top of the contact is above the surface 27 of the insulator 24.

The insulator strip 24 is formed with an integral sealing lip 29 of circular shape closely surrounding each aperture, the lip being formed in the moulding of the strip. As shown in Figures 1 and 2, the lip is of triangular section and projects above the strip surface to a greater height than does the top of the contact 25.

The beryllium copper conductor 26 extends out of the strip 24 and through an aperture 31 in the upstanding side wall 17 of the frame. The conductor is then bent downwardly through the slot 32 in which the bezel retainer latching flange 23 will be inserted. All the conductors 26, in this example, extend downwardly and below the bottom of the frame 14to connect to a further electrical component in the form of a printed circuit board 33, shown in Figure 4. These connections may be both electrical and mechanical, so that the connector assembly containing the LCD is supported by the printed circuit board, and, for example, the LCD may thereby be mounted in an aperture in a case panel 35.

The upper support face 15 of the frame 14 is formed with rigid part-spherical protruberance, in the form of a pip 34, immediately below each contact 25.

In use, the LCD is inserted into the recess in the upper face of the base frame, in which it is located both longitudinally and laterally by the end and side walls respectively of the frame. The LCD is pressed downwards into the base frame recess by the bezel retainer 22, the beads 36 on the bottoms of flanges 23 latching under the rails 30 to hold the bezel down.

The resilient insulator strip 24 is thereby compress ed, and Figure 3 illustrates what happens to the contact and its sealing lip.

The underside of the LCD flange 13 contacts the top of the annular sealing lip 29 and compresses it downwards. The whole connector is pushed downwards towards the surface 15 of the base. The rigid support pip 34 under the contact compresses the elastomer of the insulator under the contact, thus exerting a resilient upwards force on the contact 25.

The lip 29 is compressed so far that the contact 25 meets the conductive strip above it on the underside of LCD flange 13. The LCD is held in this position (illustrated in Figure 3) by the latching flanges 23 on the bezel retainer (not shown in Figure 3).

The contact 25 is urged against the LCD conductive strip by the resilience of the elastomer insulator immediately underneath it, compressed between it and the support pip 34. The sealing lip is also resiliently compressed against the LCD flange, to seal around the actual area of electrical contact and protect it from the outside atmosphere, with only a small volume of atmosphere trapped within the seal.

In order to eliminate from the contact area even this small volume of atmosphere, when the connection is made as aforesaid, that space may be filled (before the LCD is fitted) with an inert paste or grease, for example a silicone-based grease; suitable examples are those commercially available from 1 .C.1. Ltd. under the designation M 494 and from the British Central Electric Co. under the designation MS4.

The electrical connector described in the foregoing example is advantageous in that it seals each electrical contact against entry of the surrounding atmosphere, and reduces to a very small volume or eliminates completely the volume of atmosphere trapped around each contact within its seal when the connection is made. Furthermore the contacts on the connector and the LCD (or other rigid body) meet by movement perpendicular to themselves so that negligible scraping abrasion of contact surfaces occurs, and the sealing lip which also engages the rigid body is soft and will not damage it.

It will be apparent that, although the beryllium copper strip of the conductors 26 is flexible to a certain extent, it may be necessary to make the apertures 31 in the base frame side wail of appropriate dimensions to allow the conductors 26 to move nearer the base face 15, between the positions illustrated respectively in Figures 2 and 3.

It will be seen that the underside of the LCD panel is supported in an upward direction only by the resilient urging of the elastomeric insulator 24, although the upper side of the LCD panel is held by the bezel retainer 22. The flexibility inherent in the shape and material of the conductors 26 may give a certain amount of flexibility to the mounting of the connector assembly on the printed circuit board.

These features provide a certain amount of buffering of the LCD panel against mechanical shock.

The invention is not restricted to the details of the foregoing example.

Claims (20)

1. An electrical connector for making electrical connection to a substantially rigid body, which electrical connector comprises: a plurality of electrically conducting contacts; a resilient insulator overlying the contacts and having an aperture opposite each contact; the insulator having a sealing lip or rim surrounding each aperture; whereby when the connector is pressed against the body so that each contact connects to the body through its associated aperture, the sealing lip or rim surrounding that aperture forms a seal against the body and surrounding the contact.

2. An electrical connector as claimed in Claim 1, in which the shape of the sealing lip is preformed in the resilient insulator.

3. An electrical connector as claimed in Claim 2, in which the lip is preformed by moulding.

4. An electrical connector as claimed in any of the preceding claims, in which the resilient insulator is moulded with the electrical contacts embedded therein.

5. An electrical connector as claimed in any of the preceding claims, in which the arrangement is such that the contact is urged towards the body by resilient means behind it.

6. An electrical connector as claimed in Claim 5, in which the resilient means is provided by part of the resilient insulator behind the contact.

7. An electrical connector as claimed in Claim 6, in which the connector also comprises a substantially rigid backing, and in which a projection or protruberance is provided thereon opposite each contact to assist in resiliently urging the contact towards the body.

8. An electrical connector as claimed in any of the preceding claims, in which the relative arrangement of each contact with respect to the overlying resilient insulator is such that, before the resilient insulator is compressed against the body, each contact protrudes through its overlying aperture beyond the surface of the insulator, and the surrounding sealing lip is upstanding from the surface beyond the protruding contact.

9. An electrical connector as claimed in Claim 8, in which the space within the sealing lip and overlying the contact is filled with an inert substance.

10. An electrical connector as claimed in any of Claims 1 - 9, in which the electrical conducting contact is of beryllium copper.

11. An electrical connector as claimed in any of Claims 1 - 10, in which the resilient insulator is an elastomer.

12. The combination of two or more electrical connectors as claimed in any of Claims 1 - 11, with a common substantially rigid mount therefor.

13. An electrical connector, substantially as hereinbefore described with reference to, and illustrated in, the accompanying drawings.

14. The combination of an electrical connector as claimed in any of the preceding claims with a substantially rigid mount therefor.

15. The combination as claimed in Claim 14, in which the mount has a first part underlying the connector and a second part upstanding from the first part, at least one of the electrical contacts being formed as part of an elongated conductor which protrudes from the resilient insulator and extends through an aperture in the second part of the mount.

16. The combination as claimed in Claim 15, in which the remote end of the elongated conductor is adapted to be connected to a further electrical component.

17. The combination as claimed in Claim 16, in which such electrical connection is also adapted to mechanically connect the component.

18. The combination as claimed in Claim 17, further comprising clamping means for pressing a substantially rigid body, to which electrical connection is to be made, against the electrical connector.

19. The combination as claimed in Claim 18, in which the clamping means mounts the substantially rigid body on the electrical connector and its mount.

20. The combination of an electrical connector with a substantially rigid mounttherefor, substantially as hereinbefore described with reference to, and illustrated in, the accompanying drawings.