Patent Description:
Flat-wire, flexible circuits provide a lighter and cheaper alternative to traditional wire harnesses for interconnecting electrical circuits of a vehicle. These flexible circuits may consist of flat-wire conductors that are protected by an insulating body. The insulating body exposes the flat-wire conductors at a connection area. An electrical connector attaches to the connection area of the flexible circuit to connect one or more of the flat-wire conductors to an electrical circuit of a vehicle. Without the insulating body there to protect the connection area, the flat-wire conductors within the connection area are susceptible to moisture that may enter the connection area.

<CIT> disclose a flexible printed circuit board (FPCB) interconnection device that comprises a first FPCB having a first connection terminal, a second FPCB having a second connection terminal connected to the first connection terminal, a casing connecting member for connecting the first and second connection terminals, a cover for covering an opened upper portion of the casing connecting member, and an elastic pressing portion provided on a lower surface of the cover for elastically pressing the first connection terminal and the second connection terminal. Further examples of connectors for connecting terminals to a flexible circuit are known from <CIT>, <CIT>, and <CIT>.

This disclosure describes a watertight electrical connector for connecting to flat-wire conductors of a flexible circuit and a watertight electrical connection system to flat-wire conductors of a flexible circuit. Even without the insulating body there to protect the connection area, the flat-wire conductors within the connection area are protected from moisture by a watertight compression seal that contours to the surface of the connection area. The watertight compression seal does not damage or alter the flexible circuit and is reusable.

Preferred embodiments are the subject matter of the dependent claims.

This summary is provided to introduce simplified concepts for watertight electrical connection systems to flat-wire conductors of flexible circuits, which is further described below in the Detailed Description and Drawings. For ease of description, the disclosure focuses on automotive systems; however, the techniques are not limited to automobiles but apply to flexible circuits of other types of vehicles and systems. This summary is not intended to identify essential features of the claimed subject matter, nor is it intended for use in determining the scope of the claimed subject matter.

The details of one or more aspects of watertight electrical connection systems to flat-wire conductors of flexible circuits are described in this document with reference to the following drawings. The same numbers are used throughout the drawings to reference like features and components:.

This disclosure describes a watertight electrical connector for connecting to flat-wire conductors of a flexible circuit and a watertight electrical connection system to flat-wire conductors of a flexible circuit. While flexible printed circuits are primarily discussed and shown herein, it will be appreciated that the present disclosure is directed to any type of flexible circuit. The conductive circuit traces or "flat-wire conductors" of a flexible circuit, for example, could be applied using any suitable deposition process, including, but not limited to, deposition processes (physical/chemical vapor deposition, sputtering, etc.) and printing processes (screen printing, lithography, inkjet, etc.). An automobile may include many flexible circuits that connect to various types of vehicle electrical circuits, such as lighting systems, climate control systems, automated or assistive driving systems, sensor systems, electrical drive systems, engine control systems, and any other electrical component that connects to a flexible circuit in a vehicle. These flexible circuits include flat-wire conductors made from aluminum or tin-plated copper. The flat-wire conductors are protected by an insulating body formed around the flat-wire conductors. The flexible circuit can have an irregular profile and vary in thickness depending on size and location of the flat-wire conductors it surrounds. For example, areas of the insulating body that surround the flat-wire conductors may be thicker than other areas of the insulating body near the edges or in between conductors where no flat-wires exist.

The insulating body exposes the flat-wire conductors at specific connection areas of the flexible circuit. These connection areas are shaped to accommodate an electrical connector. Seating the electrical connector onto a connection area of a flexible circuit couples connector terminals of the electrical connector to an electric circuit through one or more of the flat-wire conductors of the flexible circuit. Without the insulating body there to protect the connection area, the flat-wire conductors within the connection area are susceptible to moisture that may enter the connection area.

A watertight electrical connection system is described including a watertight electrical connector that houses connector terminals within a cavity. A contact surface of the watertight electrical connector mates with the flat-wire conductors at a connection area on a surface of the flexible circuit. The connection area of the flexible circuit may be of variable thickness in some places. A seal surrounds an opening to the cavity to form a watertight connection between the connector terminals and the flat-wire conductors within the connection area of the flexible circuit. A retainer fits over the flexible circuit and onto the watertight electrical connector to compress the seal to form the watertight connection between the surface of the flexible circuit and the contact surface, which may be of variable thickness. In this way, the connection is impermeable to moisture. Even without the insulating body there to protect the connection area, the flat-wire conductors within the connection area protected from moisture by compression of the seal.

<FIG> illustrates an example of a watertight electrical connector <NUM> for connecting to flat-wire conductors of a flexible circuit. The watertight electrical connector <NUM> includes a first portion <NUM>-<NUM> that supports connector terminals <NUM>, and a second portion <NUM>-<NUM> that houses the connector terminals <NUM> within a cavity <NUM>. A contact surface <NUM> of the second portion <NUM>-<NUM> is configured to mate with one or more of the flat-wire conductors within a connection area on a surface of a flexible circuit.

The connector terminals <NUM> protrude slightly through an opening of the cavity <NUM> that passes through the contact surface <NUM> of the watertight electrical connector <NUM>. A seal <NUM> surrounds the opening to the cavity <NUM> to form a watertight connection between the connector terminals <NUM> housed within the cavity <NUM> and one or more flat-wire conductors within a connection area on a surface of a flexible circuit (not shown). In some examples, a structure <NUM> maintains the seal <NUM> around the opening to the cavity <NUM> while allowing for lateral expansion of the seal <NUM> caused by vertical compression of the seal <NUM> when the seal <NUM> is compressed by the retainer.

The seal <NUM> is a silicon ring that is shaped to be larger than the opening to the cavity <NUM>, but smaller than the perimeter of the contact surface <NUM>. The seal <NUM> is not limited to silicon and may be made from other suitable materials that can compress around the edges of a flexible circuit, adjust to a variable thickness of the flexible circuit, and return to uncompressed form. While the seal <NUM> may be attached to the contact surface <NUM>, e.g., using an adhesive, the seal <NUM> does not adhere to the flexible circuit when the watertight electrical connector <NUM> is attached. That is, the seal <NUM> does not damage or leave any residue behind when disconnected from the flexible circuit. The seal <NUM> may be reusable this way.

The watertight electrical connector <NUM> forms a watertight connection when a retainer (not shown) is fitted over the flexible circuit and attached to the watertight electrical connector <NUM> to compress the seal <NUM> and form the watertight connection between flat-wire conductors of the flexible circuit and the connector terminals <NUM> protruding through the contact surface <NUM>. <FIG> illustrate a sequence of states <NUM>-<NUM> through <NUM>-<NUM> that an example watertight electrical connection system <NUM> is in when connecting to flat-wire conductors of a flexible circuit. <FIG> shows the watertight electrical connection system <NUM> in state <NUM>-<NUM> where the connector terminals <NUM> are inserted through a cavity <NUM> and seated into the watertight electrical connector <NUM>. Once the connector terminals <NUM> are seated inside the cavity <NUM>, the watertight electrical connection system <NUM> is in state <NUM>-<NUM>.

A seal <NUM> is inserted within the structure <NUM> of the watertight electrical connector <NUM> in state <NUM>-<NUM>. The structure <NUM> may include a groove, a channel, a notch, a cutout, or indentation in the contact surface <NUM> surrounding the cavity <NUM>. The structure <NUM> contains the lateral expansion of the seal <NUM> due to vertical compression caused by a retainer compressing the flexible circuit and the seal <NUM>.

<FIG> shows the watertight electrical connection system <NUM> in state <NUM>-<NUM> where the watertight electrical connector <NUM> is mated to a connection area <NUM> of a flexible circuit <NUM>. In this state, the connector terminals <NUM> contact the flat-wire conductors exposed in the connection area <NUM>.

In <FIG>, a retainer <NUM> is lowered over the flexible circuit <NUM> and attached to the watertight electrical connector <NUM> during state <NUM>-<NUM>. Protrusions <NUM> from the contact surface <NUM> of the watertight electrical connector <NUM> align the connection area <NUM> of the flexible circuit <NUM> with the retainer <NUM> and the watertight electrical connector <NUM>.

In <FIG>, the watertight electrical connection system <NUM> is in state <NUM>-<NUM> where the retainer <NUM> compresses the flexible circuit <NUM> against the seal <NUM> seated at the contact surface <NUM> of the watertight electrical connector <NUM>. The state <NUM>-<NUM> provides a watertight connection between the connector terminals <NUM> and the flat-wire conductors exposed in the connection area <NUM>. The seal <NUM> laterally expands due to vertical compression from the force of the retainer <NUM> pressing on the flexible circuit <NUM>.

<FIG> illustrates a cross-sectional view of an example watertight electrical connection system <NUM> when connected to flat-wire conductors of a flexible circuit. In the example of <FIG>, the watertight electrical connection system <NUM> is in the state <NUM>-<NUM> as illustrated in <FIG>. A watertight connection <NUM> is formed when the retainer <NUM> is fitted over the flexible circuit <NUM> and attached to the watertight electrical connector <NUM>. This compresses the seal <NUM> to make the connection between the flexible circuit <NUM> and the contact surface <NUM> of the watertight electrical connector <NUM> watertight.

<FIG> illustrates a watertight connection <NUM> formed within an example watertight electrical connection system for connecting to flat-wire conductors of a flexible circuit. <FIG> illustrates portions of the watertight electrical connection system <NUM> in two different states.

In a first state <NUM>-<NUM>, a connection area <NUM> exposes the flat-wire conductors <NUM> that are running through a connection area <NUM> of the flexible circuit <NUM>. The connection area <NUM> is aligned with the contact surface <NUM> of the watertight electrical connector <NUM>. In a second state <NUM>-<NUM>, the connection area <NUM> of the flexible circuit <NUM> is brought into contact with the seal <NUM> to form watertight connections <NUM> around the cavity <NUM> that houses the connector terminals <NUM>. The retainer <NUM> squeezes the seal between the connection area <NUM> of the flexible circuit <NUM> and the contact surface of the watertight electrical connector <NUM>.

<FIG> illustrates an additional example of a watertight electrical connection system <NUM>-<NUM> for connecting to flat-wire conductors of a flexible circuit. In state <NUM>-<NUM>, the watertight electrical connection system <NUM>-<NUM> is formed by placing the flexible circuit over the cavity of the watertight electrical connector <NUM> and in contact with the seal <NUM>. In state <NUM>-<NUM>, the retainer <NUM> is attached to the watertight electrical connection system <NUM>-<NUM>. The retainer <NUM> may include tabs that clip into protrusions <NUM> to hold the retainer <NUM> in place over the flexible circuit <NUM>. In state <NUM>-<NUM>, the watertight electrical connection system <NUM>-<NUM> forms a watertight connection <NUM>, even between the contact surface <NUM> and portions of the flexible circuit <NUM> with a variable thickness.

The watertight compression seal <NUM> does not damage or alter the flexible circuit <NUM> and is reusable if detached from the flexible circuit <NUM> and reused elsewhere. With a single compression seal <NUM> beneath the flexible circuit <NUM>, and the force of the retainer <NUM> pressing down on the flexible circuit <NUM>, the watertight electrical connection system <NUM> creates an impermeable watertight connection <NUM> between a flat or even irregular surface of the flexible circuit <NUM> (as shown) and the seal <NUM>.

In some implementations of the electrical connector, the spring terminal may be integrated within an electrical device, thereby eliminating the need for the split blade terminal portion of the connector. In yet other implementations of the electrical connector, the split blade terminal portion of the connector may be replaced with a single blade terminal, a pin terminal or a socket terminal.

Claim 1:
A watertight electrical connector (<NUM>) for connecting to flat-wire conductors (<NUM>) of a flexible circuit (<NUM>), the watertight electrical connector comprising:
a first portion (<NUM>-<NUM>) that supports connector terminals (<NUM>);
a second portion (<NUM>-<NUM>) that houses the connector terminals (<NUM>) within a cavity (<NUM>), the second portion (<NUM>-<NUM>) having a contact surface (<NUM>) configured to mate with one or more of the flat-wire conductors (<NUM>) within a connection area (<NUM>) on a surface of the flexible circuit (<NUM>); and
a seal (<NUM>) surrounding an opening to the cavity (<NUM>) to form a watertight connection between the connector terminals (<NUM>) housed within the cavity (<NUM>) and the one or more of the flat-wire conductors (<NUM>) within the connection area (<NUM>) on the surface of the flexible circuit (<NUM>)
the watertight electrical connector being configured to form the watertight connection when a retainer (<NUM>) is fitted over the flexible circuit (<NUM>) and attached to the watertight electrical connector (<NUM>) to compress the seal (<NUM>) and form the watertight connection between the surface of the flexible circuit (<NUM>) and the contact surface (<NUM>) of the watertight electrical connector (<NUM>), wherein the connector terminals (<NUM>) protrude slightly through an opening of the cavity (<NUM>) that passes through the contact surface (<NUM>) of the watertight electrical connector (<NUM>),
characterized in that
the contact surface (<NUM>) comprises outer protrusions (<NUM>) that receive the retainer (<NUM>) and are configured to contain edges of the flexible circuit (<NUM>) to ensure alignment between the connector terminals (<NUM>) housed within the cavity (<NUM>) and the one or more of the flat-wire conductors (<NUM>) within the connection area (<NUM>) on the surface of the flexible circuit (<NUM>).