Flexible connector

Abstract

A solder bridge (1) for a vehicle windscreen, the solder bridge (1) comprises a first foot portion (11A) for connection to a vehicle windscreen and a second foot portion (11B) for connection to a vehicle windscreen, the first foot portion (11A) and second foot portion (11B) being interconnected by a flexible electrically conductive body (12).

Claims

1. A solder bridge for a vehicle windscreen, the solder bridge comprising a first major surface and a second major surface and further comprising a first foot portion for electrical connection to a vehicle windscreen and a second foot portion for electrical connection to a vehicle windscreen, the first foot portion and second foot portion being interconnected by a flexible electrically conductive body provided with insulation, wherein the first foot portion and the second foot portion are provided with insulation, a first window in the insulation is provided at the first foot portion on the first major surface and a second window in the insulation is provided at the second foot portion on the first major surface, and at least one aperture is provided in the insulation on the second major surface in or proximate the first and/or second foot portion, wherein the at least one aperture is smaller in cross-sectional area than the corresponding first and/or second window.

2. A solder bridge according to claim 1, wherein the flexible electrically conductive body comprises a connecting portion for providing, in use, an electrical connection from the solder bridge to a source of electrical power, e.g. the vehicle's electrical system.

3. A solder bridge according to claim 2, wherein the flexible electrically conductive body is formed as a unitary body comprising the connecting portion, the first foot portion, and the second foot portion.

4. A solder bridge according to claim 1, wherein the flexible electrically conductive body is fabricated from a metal foil.

5. A solder bridge according to claim 1, wherein the flexible electrically conductive body has a thickness of less than 100 microns.

6. A solder bridge according to claim 1, wherein the insulation is provided as a layer fabricated from a polymer.

7. A solder bridge according to claim 1, wherein the insulation is between 10 to 100 microns thick.

8. A solder bridge according to claim 1, wherein the insulation extends beyond the periphery of the flexible electrically conductive body to provide a border.

9. A solder bridge according to claim 1, further comprising an adhesive tape applied to a major surface.

10. A solder bridge according to claim 1, wherein the first foot portion and the second foot portion extend transversely beyond the periphery of the flexible electrically conductive body.

11. A pane, the pane comprising a transparent substrate having an electrically conductive structure provided thereon and an electrical connector having at least one mounting portion, at least one connecting portion, and a flat electrically conductive body, the electrical connector being secured to the electrically conductive structure at the mounting portion, wherein the mounting portion and the flat electrically conductive body is covered in encompassing insulation material and has an exposed portion on a first major surface of the electrical conductor and an aperture is provided in or proximate the at least one mounting portion on a second major surface of the electrical conductor, the aperture having a smaller cross-sectional area than the exposed portion, wherein the mounting portion extends transversely beyond the periphery of the flat electrically conductive body.

12. A pane according to claim 11, wherein the electrical connector is fabricated from a conductive material, for example, a metal foil.

13. A pane according to claim 11, wherein the flat electrically conductive body of the electrical connector has a thickness of between 40 to 100 microns.

14. A pane according to claim 11, wherein the insulation material comprises polyimide.

15. A pane according to claim 11, wherein the insulation material is between 10 to 100 microns thick.

16. A pane according to claim 11, wherein the insulation material extends beyond the mounting portion and connecting portion to provide a border.

17. A pane according to claim 11, wherein the total thickness of the flat electrically conductive body comprising encompassing insulation is between 100 microns and 500 microns thick.

18. A solder bridge according to claim 1, wherein a solder preform is applied to the first foot portion and the second foot portion in the region of the window, and the solder preform is larger than the window to provide environmental protection to the underlying foot portion.

19. A solder bridge according to claim 1, further comprising an opening in the insulation of the flexible electrically conductive body for providing, in use, an electrical connection between the solder bridge and a source of electrical power.

20. A solder bridge for a vehicle windscreen, the solder bridge comprising a first major surface and a second major surface and further comprising a first foot portion for electrical connection to a vehicle windscreen and a second foot portion for electrical connection to a vehicle windscreen, the first foot portion and second foot portion being interconnected by a flexible electrically conductive body provided with insulation, a first window in the insulation is provided at the first foot portion on the first major surface and a second window in the insulation is provided at the second foot portion on the first major surface, and wherein a solder preform is applied to the first foot portion and the second foot portion in the region of the window, and the solder preform is larger than the window to provide environmental protection to the underlying foot portion.

Description

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

(1) The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee.

(2) Embodiments of the invention will now be described by way of example only with reference to the accompanying drawings in which:

(3) FIG. 1A is a plan view of the first major surface of a solder bridge according to a first embodiment of the invention;

(4) FIG. 1B is a plan view of the second major surface of the solder bridge of FIG. 1A;

(5) FIG. 1C is a cross-sectional view of the solder bridge of FIG. 1A;

(6) FIG. 2 is a plan view of the first major surface of an electrical connector according to a second embodiment of the invention;

(7) FIG. 3 is a plan view of a solder bridge according to a third embodiment of the invention;

(8) FIG. 4 is a schematic of a vehicle windscreen comprising the solder bridge of FIG. 1A, or FIG. 3, or the electrical connector of FIG. 2;

(9) FIG. 5 is a graph showing the critical stress area of a connector according to an Example of the invention;

(10) FIG. 6 is a graph showing the critical stress area of a connector according to a Comparative Example of the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

(11) Referring now to FIGS. 1A to 1C, there is shown a solder bridge 1 according to a first embodiment of the invention. The solder bridge 1 comprises a first major surface 1A (shown in FIG. 1A) for facing a substrate, for example a windscreen pane, in use, and a second major surface 1B (shown in FIG. 1B).

(12) The solder bridge 1 comprises a first foot portion 11A, a second foot portion 11B, a conductive portion 12, encapsulating insulation 13, and a connecting portion 14.

(13) The first foot portion 11A, second foot portion 11B and conductive portion 12 are integrally formed as a unitary body. As shown, the first foot portion 11A, second foot portion 11B and conductive portion 12 provide a dumb-bell-type shape, each of the first and second foot portion 11A, 12A extending transversely beyond the periphery of the conductive portion 12. The first foot portion 11A and second foot portion 11B are shown as being rectangular, e.g. square, in plan although other shapes (circular, triangular and so on can be deployed). As above, in each case the foot portions 11A, 11B will preferably extend transversely beyond the conductive portion 12.

(14) The first foot portion 11A comprises a first window 15A through the insulation 13, and the second foot portion 11B comprises a second window 15B through the insulation 13, both on the first major surface 1A of the solder bridge 1. The first window 15A is provided with a first solder deposit 16A, and the second window 15B of the second foot portion 11B is provided with a second solder deposit 16B, both on the first major surface 1A of the solder bridge 1.

(15) As shown in FIG. 1A, the solder deposit 16A, 16B is larger than the corresponding first window 15A, and second window 15B, although it may be smaller or the same size. Preferably each of the solder deposits 16A, 16B covers a respective window 15A, 15B to prevent (or at least inhibit) any environmental or other damage to the underlying foot portion 11A, 11B.

(16) The insulation 13 provides a border B that extends beyond the periphery of the first and second foot portions 11A, 11B and the conductive portion 12 to provide protection to the conductive portion 12 from damage by the external environment. The insulation 13 comprises a first aperture 17A, a second aperture 17B, and an opening 18 on the second major surface 1B of the solder bridge 1.

(17) In FIG. 1C, there is shown a view of the cross-section A of the solder bridge 1 shown in FIG. 1B. The insulation 13 encloses or encompasses the conductive portion 12 of the solder bridge 1, such that the conductive portion 12 is exposed at the locations of the first and second windows 15A, 15B, the first and second apertures 17A, 17B, and the opening 18 only.

(18) In this embodiment, the conductive portion 11 forms a flexible electrically conductive body and the solder bridge 1 is flat.

(19) The first and second foot portions 11A, 11B are, in use, each secured directly to an electrically conductive structure (not shown) of, say, a windscreen, via the solder deposits 16A, 16B.

(20) The opening 18 in the insulation 13 exposes the conductive portion 12 at the connecting portion 14 of the solder bridge 1, which provides, in use, an electrical connection from the solder bridge 1 to a source of electrical power. The connecting portion 14 may be connected to a cable (not shown) to provide an electrical connection from the electrical system of the vehicle to the electrically conductive structure (not shown).

(21) During manufacture of a vehicle windscreen, the first major surface 1A of the solder bridge 1 is presented against an electrically conductive structure (not shown) on a fragile substrate such as a windscreen (not shown). Heat energy is applied to the first and second apertures 17A, 17B, which is transmitted to the solder deposits 16A, 16B causing the solder deposits 16A, 16B to melt and flow between the fragile substrate and the conductive portion 12 at the first and second windows 15A, 15B located on the first and second foot portions 11A, 11B of the solder bridge 1. The heat energy is then removed from the first and second apertures 17A, 17B, causing the solder deposits 16A, 16B to solidify and hence secure the solder bridge 1 to the electrically conductive structure of the fragile substrate. The connecting portion 14 may then be connected to the source of electrical power within the vehicle.

(22) In a most preferred embodiment, the solder bridge 1 is formed from a copper foil, e.g. thickness of 70 micron, encased in an insulation 13 provided by a polyimide layer on each side of the solder bridge with e.g. thickness of 25 microns, such that the solder bridge 1 has a total thickness of approximately 120 microns. In a preferred embodiment, the solder bridge 1 has a length of approximately 60 mm and a width of approximately 10 mm.

(23) Preferably the solder deposits 16A, 16B are lead free. For example, a suitable solder composition consists of 96.5% tin, 3% silver, and 0.5% copper (e.g. marketed as SAC305 by AIM Solder of Luton, UK).

(24) Preferably, the solder deposits 16A, 16B are approximately 5 mm in diameter, and approximately 100 to 200 microns thick, such that the volume of solder is relatively small.

(25) Advantageously, the selection of material types and thicknesses used to form the solder bridge 1 enable the solder bridge 1 to be flexible, i.e. it is capable of bending easily without breaking or being damaged. Advantageously, this enables the solder bridge 1 to provide an electrical connection to a transparent substrate whilst substantially reducing stress when they are soldered onto the transparent substrate.

(26) More advantageously, the conductive portion 12 of the solder bridge 1 is thin, which enables rapid heat transferal from the first and/or second apertures 17A, 17B through the conductive portion 12, and into the solder deposits 16A, 16B. In addition, the solder deposits 16A, 16B are thin (e.g. between 100 to 200 microns) and of low volume. The thin conductive portion 12 enables heat to be transferred rapidly to melt the solder to secure the solder bridge 1 to a fragile substrate during manufacture. The solder deposit 16A, 16B are of low volume, which means that the solder will rapidly cool. This, the heat energy applied to secure the solder bridge 1 to a windscreen is low and the thermal insult to the fragile substrate is low.

(27) The solder bridge 1 may further comprise an adhesive portion (e.g. an adhesive tape) to help secure the solder bridge to a substrate in use. The adhesive portion may surround the first window 15A and/or the second window 15B and/or be located between the first and second foot portions 11A, 11B.

(28) Referring now to FIG. 2, there is shown an electrical connector 2 according to a further embodiment of the invention. Only the first major surface is shown 2A, which is the substrate-facing surface, for example a transparent-substrate-facing surface.

(29) The electrical connector 2 comprises a first end 21A and a second end 21B.

(30) The electrical connector 2 comprises a flat electrically conductive body 22, a mounting portion 23, a connecting portion 24, and insulation 25.

(31) The mounting portion 23 and the connecting portion 24 are both located on the first major surface 2A of the electrical connector 2. The mounting portion 23 is located at the first end 21A and the connecting portion 24 is located at the second end 21B of the electrical connector 2.

(32) The flat electrically conductive body 22, the mounting portion 24, and the connecting portion 25 are formed as a unitary body.

(33) The insulation 25 comprises a window 26, located at or proximate the mounting portion 23.

(34) The mounting portion 23 is provided with a solder deposit 27 on the first major surface 2A of the electrical connector 2. The solder deposit 27 preferably covers the window 26 so as to ensure that the otherwise exposed part of the foot portion 11A is not exposed.

(35) The insulation 25 further comprises an window or opening 28 located at or proximate the connecting portion 24 on the first major surface 2A of the electrical connector 2.

(36) The connecting portion 24 may further comprise a potting compound 29 to provide protection to the electrical connection formed between the electrical connector 2 and the electrically conductive structure of the transparent substrate of the pane.

(37) The insulation 25 extends beyond the periphery of the electrically conductive body 22, mounting portion 23, and connecting portion 34 to define a border B′ and such that the mounting portion 23 and connecting portion 34 are exposed via the second window 26 and the window or opening 28 only, for example to provide protection to damage from the external environment.

(38) In this embodiment, the insulative portion 25 is further provided with an adhesive tape 29. Advantageously, addition of the adhesive tape 29 increases pull-strength of the electrical connector 2.

(39) In use, the mounting portion 23 is secured directly to an electrically conductive structure (not shown) of a transparent substrate of a pane via the solder deposit 27.

(40) The window or opening 28 in the insulation 25 exposes the connecting portion 24 of the electrical connector 2, which provides, in use, an electrical connection from the electrical connector 2 to a source of electrical power. The connecting portion 24 may each be connected to a cable (not shown) to provide an electrical connection from the electrical system of the vehicle to the electrically conductive structure (not shown).

(41) In embodiments, the electrical connector 2 may be provided with one or more openings or apertures (not shown) located on the opposite side of the electrical connector 2 to the solder deposit 27. The electrical connector 2 may be connected during manufacture to the electrically conductive structure of the transparent substrate of the pane via the solder deposit 27 at the mounting portion 23 in a like-manner to that described for the solder bridge 1 of FIGS. 1A,1B.

(42) Advantageously, the selection of material types and thicknesses used to form the electrical connector 2 enable the electrical connector 2 to be flexible, i.e. it is capable of bending easily without breaking or being damaged. Advantageously, this enables the electrical connector 2 to provide an electrical connection to a transparent substrate whilst substantially reducing stress when they are soldered onto the transparent substrate.

(43) Referring now to FIG. 3, there is shown a solder bridge 3 according to a third embodiment of the invention. The solder bridge 3 has many features in common with the solder bridge 1 of FIGS. 1A-1C, and like-references are designated with a prime (′) and will not be described further. Only the features that differ from those described for solder bridge 1 of FIGS. 1A-1C are further described.

(44) In this embodiment, the solder bridge 3 comprises a conductive portion 32 that is substantially T-shaped. The solder bridge 3 comprises a connecting portion 34, which is located towards the base portion or foot 33 of the T-shaped conductive portion 32.

(45) The solder bridge 3 is shown to be electrically connected by the connecting portion 34 to a cable 41 via a plug 42. In use, the connecting portion 34 is connected to the vehicle's electrical system via the cable 41.

(46) Referring now to FIG. 4, there is shown a vehicle windscreen 4 comprising a pane 43 which is a fragile and transparent substrate. The pane 43 comprises an electrically conductive structure 44 and the solder bridge 1 of FIG. 1A-1C, or FIG. 3, or the electrical connector of FIG. 2. It is shown that the solder bridge 1 or the electrical connector 2 is connected to the electrically conductive structure 44 by the first and second foot portions (not shown).

(47) To further exemplify the invention, reference is made to the following non-limiting Examples.

Example 1

(48) An electrical connector was fabricated in accordance with the above description and as shown in FIG. 2. The electrical connector was formed from a copper foil of a thickness of 70 micron, encased in an insulative layer provided by a polyimide Kapton® tape, of a thickness of 25 microns. The solder deposit was provided as SAC305 by AIM Solder of Luton, UK in a thickness of 100 microns.

(49) The electrical connector has a total thickness of approximately 120 microns, a length of approximately 105 mm, and a width of approximately 9 mm.

(50) Referring now to FIG. 5, there is shown a von Mises stress model 3 for the electrical connector fabricated in Example 1 when connected to a fragile substrate, e.g. glass. It is shown that the critical stress area for the electrical connection between the electrical connector and the transparent substrate is 2.91×10.sup.−4 mm.sup.2.

Comparative Example 1

(51) A prior art solder bridge was fabricated. The electrical connector had a thickness of 0.4 mm and was rigid. The solder deposit was provided as SAC305 by AIM Solder of Luton, UK in a thickness of 200 microns.

(52) Referring now to FIG. 6, there is shown a von Mises stress model 4 for the electrical connector fabricated for Comparative Example 1 when connected to a fragile substrate, e.g. glass. It is shown that the critical stress area for the electrical connection between the electrical connector and the transparent substrate is 8.69×10.sup.−4 mm.sup.2.

(53) The results show a 67% reduction in the critical stress area at the solder-glass interface for Example 1 in comparison with Comparative Example 1.

(54) It will be appreciated by those skilled in the art that several variations to the aforementioned embodiments are envisaged without departing from the scope of the invention. It will also be appreciated by those skilled in the art that any number of combinations of the aforementioned features and/or those shown in the appended drawings provide clear advantages over the prior art and are therefore within the scope of the invention described herein.