FLEXIBLE MULTILAYER ENCAPSULATION OF ELECTRICAL CONNECTIONS

Abstract

An electrical connection encapsulation device for electrically connecting a flexible flat cable to discrete electrical wires. The device includes a flexible flat cable with a dielectric, planar, flexible carrier and at least one electrically conductive line attached to at least one surface, first and second flat, soft and pliable material layers attached to the first surface and the second surface of the flexible carrier, respectively, by adhesive bonds, at least one electrical connector member that is electrically connectable to a discrete electrical wire at one end and to the at least one electrically conductive line with the other end. The first and second layers are arranged to at least partially overlap the at least one electrically conductive line in the connecting end region in the perpendicular direction, and to extend beyond the end of the at least one electrical connector member that is facing away from the connecting end region.

Claims

1. An electrical connection encapsulation device for electrically connecting a flexible flat cable to discrete electrical wires, comprising: a flexible flat cable having a connecting end region and including at least one dielectric, planar, flexible carrier having a first surface and an opposite second surface arranged in parallel to the first surface, wherein at least one out of the first surface and the second surface is equipped with at least one electrically conductive line, being attached to the respective surface and extending at least within the connecting end region, a first flat, soft and pliable material layer that is attached to the first surface of the flexible carrier at the connecting end region by an adhesive bond, a second flat, soft and pliable material layer that is attached to the second surface of the flexible carrier at the connecting end region by an adhesive bond, at least one electrical connector member that is electrically connectable to a discrete electrical wire with one end facing away from the connecting end region, and whose other end is facing towards the connecting end region and is arranged to partially overlap the at least one electrically conductive line in a direction that is perpendicular to the surfaces of the flexible carrier for providing an electrical contact to the at least one electrically conductive line at least in an operational state, wherein the first flat, soft and pliable material layer and the second flat, soft and pliable material layer are arranged to at least partially overlap the at least one electrically conductive line in the connecting end region in the perpendicular direction, and to extend beyond the end of the at least one electrical connector member that is facing away from the connecting end region.

2. The electrical connection encapsulation device as claimed in claim 1, further comprising at least a first flat, stiff material layer that is attached by an adhesive bond to the first flat, soft and pliable material layer or to the second flat, soft and pliable material layer, to a surface facing away from the flexible carrier.

3. The electrical connection encapsulation device as claimed in claim 2, further comprising at least a second flat, stiff material layer that is attached by an adhesive bond to an open surface of the first flat, soft and pliable material layer or the second flat, soft and pliable material layer that is facing away from the flexible carrier.

4. The electrical connection encapsulation device as claimed in claim 1, wherein at least one of the adhesive bonds is provided by a layer of adhesive material.

5. The electrical connection encapsulation device as claimed in claim 1, wherein at least one of the adhesive bonds is provided by a double-sided adhesive tape

6. The electrical connection encapsulation device as claimed in claim 1, wherein an adhesive material of at least one of the adhesive bonds is formed by a pressure-sensitive adhesive.

7. The electrical connection encapsulation device as claimed in claim 1, wherein the second flat, soft and pliable material layer, which has a surface that is facing towards the surface of the planar, flexible carrier that is equipped with the at least one electrically conductive line, comprises at least one aperture that is configured for taking up, in an operational state, at least a portion of the at least one electrically conductive line or at least a portion of the at least one electrical connector member.

8. The electrical connection encapsulation device as claimed in claim 1, wherein at least one of the flat, soft and pliable material layers is made at least for a most part from a soft polymeric foam, a synthetic textile or a combination of both.

9. The electrical connection encapsulation device as claimed in claim 1, wherein the at least one dielectric, planar, flexible carrier is made at least for a most part from a material that is selected from a group of materials formed by polyethylene terephthalate, polyimide, polyetherimide, polyethylene naphthalate, polyether ether ketone and selected combinations of at least two of these materials.

10. A flexible flat cable-to-electrical wire encapsulated connector device, comprising an electrical connection encapsulation device as claimed in claim 1, the flexible flat cable having a plurality of electrically conductive lines, the flexible flat cable-to-electrical wire encapsulated connector device further including a plurality of discrete electrical wires, wherein each of the discrete electrical wires is electrically connected to at least one of the electrical connector members.

11. A method for producing a flexible flat cable-to-electrical wire encapsulated connector device as claimed in claim 10, the method comprising at least the following steps: preparing a first subassembly unit that comprises the flexible flat cable and the plurality of discrete electrical wires being electrically connected to the plurality of electrical connector members, preparing a second subassembly unit comprising at least the second flat, soft and pliable material layer and a layer of adhesive material or the double-sided adhesive tape, preparing a third subassembly unit comprising at least the first flat, soft and pliable material layer and a layer of adhesive material or the double-sided adhesive tape, arranging the first subassembly unit on a conveyor unit, by operating the conveyor unit, transporting the first subassembly unit to a first laminating station , pressing the first subassembly unit and the second subassembly unit against each other, with the layer of adhesive material or the double-sided adhesive tape facing the plurality of discrete electrical wires, for establishing an adhesive bond, by operating the conveyor unit, transporting the bonded-together first subassembly unit and second subassembly unit to a second laminating station, and pressing the bonded-together first subassembly unit and second subassembly unit and the third subassembly unit against each other, with the layer of adhesive material or the double-sided adhesive tape of the third subassembly unit facing the surface of the planar, flexible carrier opposite of the surface with the plurality of discrete electrical wires, for establishing an adhesive bond.

12. The method as claimed in claim 11, wherein the conveyor unit comprises means to provide sufficient reaction force during execution of the steps of pressing.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Further details and advantages of the present invention will be apparent from the following detailed description of not limiting embodiments with reference to the attached drawing, wherein:

[0060] FIG. 1 schematically illustrates a flexible flat cable-to-electrical wire encapsulated connector device in an operational state, comprising an electrical connection encapsulation device in accordance with an embodiment of the invention, in a perspective view;

[0061] FIG. 2 schematically illustrates another embodiment of an electrical connection encapsulation device in accordance with the invention, in a sectional side view;

[0062] FIG. 3 schematically shows a setup for executing the method pursuant to FIG. 3;

[0063] and

[0064] FIG. 4 is a flow chart of a method for producing the flexible flat cable-to-electrical wire encapsulated connector device pursuant to FIG. 2.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0065] FIG. 1 schematically illustrates a flexible flat cable-to-electrical wire encapsulated connector device 10 in an operational state, comprising an electrical connection encapsulation device 12, in a perspective view.

[0066] The electrical connection encapsulation device 12 includes a flexible flat cable 14. The flexible flat cable 14 comprises a dielectric, planar, flexible carrier 16 that has a first surface 18, which is facing upwards in the illustration of FIG. 1, and an opposite second surface 20, which is facing downwards in the illustration of FIG. 1, and is arranged in parallel to the first surface 18.

[0067] In this specific embodiment, the dielectric, planar, flexible carrier 16 is completely made from polyetherimide (PEI) and has a thickness of about 75 μm. In other embodiments, the dielectric, planar, flexible carrier may be made at least for a most part from a material that is selected from a group of materials formed by polyethylene terephthalate (PET), polyimide (PI), polyethylene naphthalate (PEN), polyether ether ketone (PEEK) and selected combinations of at least two of these materials. In other embodiments, a thickness of the dielectric, planar, flexible carrier may be selected in a range between 75 μm and 0.35 mm.

[0068] The second surface 20 of the flexible flat cable 14 is equipped with a plurality of four electrically conductive lines 22, 24, 26, 28. The four electrically conductive lines 22, 24, 26, 28 are attached to the second surface 20 in a spaced manner and run parallel to a direction of extension 42 of the dielectric, planar, flexible carrier 16. The four electrically conductive lines 22, 24, 26, 28 may be attached to the second surface 20 by applying electrically conductive ink comprising silver or copper in a screen printing or ink jet printing process in combination with a curing process, or, alternatively, by laminating copper foil onto the second surface 20, or by any other method that appears to be suitable to those skilled in the art. A thickness of the four electrically conductive lines 22, 24, 26, 28 in a direction 44 that is perpendicular to the surfaces 18, 20 of the flexible carrier 16 (in the following also referred to as “perpendicular direction 44”) may range between 10 μm and 30 μm and in this specific embodiment is selected to be about 20 μm.

[0069] The flexible flat cable 14 comprises a connecting end region 40. The four electrically conductive lines 22, 24, 26, 28 extend to an outer end of the connecting end region 40, where each one of the four electrically conductive lines 22, 24, 26, 28 is ending in a terminal pad 30. The electrical connection encapsulation device 12 further includes a plurality of four electrical connector members 32, 34, 36, 38, which in this specific embodiment are designed as crimp connectors, arranged to partially overlap the electrically conductive lines 22, 24, 26, 28 in the perpendicular direction 44.

[0070] The flexible flat cable-to-electrical wire encapsulated connector device 10 further includes a plurality of two discrete electrical wires 46, 48 made from copper. Each of the two discrete electrical wires 46, 48 is electrically connected by crimping to an end of one of the electrical connector members 32, 38 that is facing away from the connecting end region 40. The other ends of the electrical connector members 32, 38 that are facing away from the electrical wires 46, 48 match to the terminal pads and partially overlap the respective electrically conductive line 22, 28 in the perpendicular direction 44. Each of these other ends provide an electrical contact between one of the discrete electrical wires 46, 48 and one of the electrical conductive lines 22, 28 that are arranged close to outer edges of the flexible flat cable 14.

[0071] The electrical connection encapsulation device 12 further includes a first flat, soft and pliable material layer 50 of rectangular shape that is attached to the first surface 18 of the flexible carrier 16 at the connecting end region 40 by an adhesive bond. The first flat, soft and pliable material layer 50 is arranged to partially overlap the four electrically conductive lines 22, 24, 26, 28 in the connecting end region 40 in the perpendicular direction 44 and to extend beyond the ends of the four electrical connector members 32, 34, 36, 38 that are facing away from the connecting end region 40, covering a portion of the two discrete electrical wires 46, 48. In this specific embodiment, the adhesive bond is provided by a double-sided adhesive tape. In other embodiments, the adhesive bond may be provided by a layer of adhesive material. In both cases, the adhesive may be formed by a pressure-sensitive adhesive. A thickness of the adhesive bond may range between 50 μm and 1.0 mm. Adhesive bonds provided by a double-sided adhesive tape may tend to be closer to the upper limit, whereas adhesive bonds provided by a layer of adhesive material may tend to be closer to the lower limit.

[0072] The electrical connection encapsulation device 12 further comprises a second flat, soft and pliable material layer 52 of rectangular shape that is attached to the second surface 20 of the flexible carrier 16 at the connecting end region 40 by an adhesive bond. The second flat, soft and pliable material layer 52 is arranged to partially overlap the four electrically conductive lines 22, 24, 26, 28 in the connecting end region 40 in the perpendicular direction 44 and to extend beyond the ends of the four electrical connector members 32, 34, 36, 38 that are facing away from the connecting end region 40, covering a portion of the two discrete electrical copper wires 46, 48. In this specific embodiment, the adhesive bond is provided by a double-sided adhesive tape. In other embodiments, the adhesive bond may be provided by a layer of adhesive material. In both cases, the adhesive may be formed by a pressure-sensitive adhesive.

[0073] The first 50 and the second flat, soft and pliable material layer 52 have same outer dimensions and are arranged to completely overlap each other in the perpendicular direction 44. In this specific embodiment, they are completely made from a soft polymeric foam, namely expanded polyethylene foam (EPE foam), which is readily commercially available. In other embodiments, though, they may be made, at least for a most part, also from a synthetic textile or from a combination of a soft polymeric foam and a synthetic textile. A thickness of the first flat, soft and pliable material layer 50 and the second flat, soft and pliable material layer 52 in the perpendicular direction 44 may be selected in a range between 0.1 mm and 5.0 mm. The thickness of the first flat, soft and pliable material layer 50 and the thickness of the second flat, soft and pliable material layer 52 may be chosen to be equal, but they may as well be chosen to be different, depending on the specific application.

[0074] The second flat, soft and pliable material layer 52, which has a surface that is facing towards the surface 20 of the planar, flexible carrier 16 that is equipped with the plurality of four electrically conductive lines 22, 24, 26, 28, comprises an aperture 54 (or through-hole) that in this specific embodiment is square-shaped, and that is configured for taking up, in the operational state, an end portion of two 34, 36 of the plurality of four electrical connector members 32, 34, 36, 38, which are electrically connected to electrically conductive lines 24, 26 that are arranged in a middle region of a width of the flexible flat cable 14. During a manufacturing process, the aperture 54 provides access to the two 34, 36 of the plurality of four electrical connector members 32, 34, 36, 38 and further provides installation space for installing bulk electrical components such as a resistor 56, as indicated in FIG. 1, which is electrically connected between the two electrical connector members 34, 36 that, in turn, are electrically connected to the electrically conductive lines 24, 26 that are arranged in the middle region of the width of the flexible flat cable 14.

[0075] FIG. 2 schematically illustrates an alternative embodiment of an electrical connection encapsulation device 12′, in a sectional side view. In order to avoid unnecessary repetitions, only differences with respect to the first embodiment pursuant to FIG. 1 will be described. For features in FIG. 2 that are not described in context with the alternative embodiment, reference is made to the description of the first embodiment.

[0076] In comparison to the embodiment shown in FIG. 1, the electrical connection encapsulation device 12′ pursuant to FIG. 2 further comprises a first flat, stiff material layer 58 that is attached by an adhesive bond to a surface of the first flat, soft and pliable material layer 50 that is facing away from the flexible carrier 16. The electrical connection encapsulation device 12′ also includes a second flat, stiff material layer 60 that is attached by an adhesive bond to an open surface of the second flat, soft and pliable material layer 52 that is facing away from the flexible carrier 16.

[0077] In this specific embodiment, the first flat, stiff material layer 58 and the second flat, stiff material layer 60 are completely made from polyethylene terephthalate (PET). In other embodiments, the first flat, stiff material layer and the second flat, stiff material layer may be made, at least for a most part, from a material that is selected from a group of materials formed by polyimide (PI), polyetherimide (PEI), polyethylene naphthalate (PEN), polyoxymethylene (POM), acrylonitrile butadiene styrene (ABS), polycarbonate (PC), polyether ether ketone (PEEK), metal foil and selected combinations of at least two of these materials.

[0078] A thickness of the first flat, stiff material layer 58 and the second flat, stiff material layer 60 in the perpendicular direction 44 may be selected in a range between 10 μm and 3.0 mm. The thickness of the first flat, stiff material layer 58 and the thickness of the second flat, stiff material layer 60 may be chosen to be equal, but they may as well be chosen to be different, as indicated in FIG. 2, depending on the specific application.

[0079] The electrical connection encapsulation device 12′ comprises a dielectric protection layer 62 that is arranged to cover and to be in direct contact with a portion of the plurality of four electrically conductive lines 22, 24, 26, 28 in the connecting end region 40. The dielectric protection layer 62 extends beyond the first flat, soft and pliable material layer 50 and the second flat, soft and pliable material layer 52 in a direction away from the connecting end region 40. The dielectric protection layer 62 may be made for a most part or completely from polyurethane or any other material that appears to be suitable to those skilled in the art. A thickness of the dielectric protection layer 62 in the perpendicular direction 44 may be selected in a range between 10 μm and 80 μm.

[0080] The aperture 54 in the second flat, soft and pliable material layer 52 in this specific embodiment is arranged for taking up, in the operational state, end portions of the plurality of four electrically conductive lines 22, 24, 26, 28.

[0081] In the following, a method for producing a flexible flat cable-to-electrical wire encapsulated connector device with the electrical connection encapsulation device 12′ pursuant to FIG. 2 will be described with reference to FIGS. 2, 3 and 4, which schematically show a production setup in FIG. 3 for executing the method as show in a flow chart in FIG. 4.

[0082] The production setup includes a conveyor unit 72 comprising a linear conveyor belt 74 and a controllable electric drive (not shown) for driving the conveyor belt 74. The setup further comprises a pick and place station 76, a first laminating station 78 and a second laminating station 80. The linear conveyor belt 74 is configured to move items to at least these three stations 76, 78, 80 along one conveying direction 82. At the first laminating station 78 and at the second laminating station 80 the production setup further comprises a pressure stamp (not shown) for applying a mechanical load from above or from below, respectively, and also a sufficiently rigid platform (not shown) that is extendable during stops of the linear conveyor belt 74 to provide sufficient reaction force against a mechanical load applied by the respective pressure stamp.

[0083] A first subassembly unit 84 that comprises the flexible flat cable 14 and the plurality of two discrete electrical copper wires 46, 48 that are electrically connected to the plurality of two electrical connector members 32, 38 is prepared in a preparatory step 90. As an alternative step 90′, a plurality of first subassembly units 84 can also be prepared in advance, held in stock and procured for production.

[0084] As a second subassembly unit 86, a sandwiched assembly of the second flat, stiff material layer 60, a double-sided adhesive tape 70, the second flat, soft and pliable material layer 52, and another double-sided adhesive tape 68 is prepared in a preparatory step 92. As an alternative step 92′, a plurality of second subassembly units 86 can also be prepared in advance, held in stock and procured for production.

[0085] As a third subassembly unit 88, a sandwiched assembly of a double-sided adhesive tape 66, the first flat, soft and pliable material layer 50, another double-sided adhesive tape 64 and the first flat, stiff material layer 58 is prepared in a preparatory step 94. As an alternative step 94′, a plurality of third subassembly units 88 can also be prepared in advance, held in stock and procured for production.

[0086] In a next step 96 of the method, the first subassembly unit 84 is arranged at the pick and place station 76. By operating the conveyor unit 72, the first subassembly unit 84 is transported to the first laminating station 78 in another step 98. There, the first subassembly unit 84 and the second subassembly unit 86 are pressed against each other in a next step 100, with the double-sided adhesive tape 68 facing the plurality of discrete electrical wires 46, 48, for establishing an adhesive bond by operating the pressure stamp to apply a predetermined mechanical load from above and by extending a sufficiently rigid platform from below.

[0087] By operating the conveyor unit 72 in a next step 102, the bonded-together first 84 and second subassembly unit 86 are transported to the second laminating station 80. There, the bonded-together first 84 and second subassembly unit 86 and the third subassembly unit 88 are pressed against each other in a next step 104, with the double-sided adhesive tape 66 of the third subassembly unit 88 facing the surface 18 of the planar, flexible carrier 16 opposite of the surface 20 with the plurality of discrete electrical wires 46, 48, for establishing an adhesive bond by operating the pressure stamp to apply a predetermined mechanical load from below and by extending a sufficiently rigid platform from above.

[0088] While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive; the invention is not limited to the disclosed embodiments.

[0089] Other variations to be disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality, which is meant to express a quantity of at least two. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting scope.