Vehicles today incorporate a large number of electronic components useful to operate, activate or control many devices. For example, electronic components in an automobile door can control the operation of the windows, locks, speakers or lights. Several components for controlling the devices located in the vehicle are also incorporated in the dashboard, such as data displays (speed, temperature, state of the lights, etc.), music equipment control, telephone, clock, activation of the various switches or buttons, etc.
The electronic components are usually arranged on a rigid integrated circuit board (Printed Circuit Board, PCB) which is housed inside a protective casing, such as a rigid plastic casing, or inside a part so that said board is always protected. The aforementioned casing is usually provided with a series of connectors allowing the connection of the corresponding electrical cables extended to the equipment that is to be controlled.
However, rigid integrated circuit boards or PCBs have a series of drawbacks: On one hand, they occupy a large space, which is a great drawback in the event of integration in vehicles, in which the available space is very limited. On the other hand, since PCBs are rigid, they need a planar base for their attachment. For example, the support surfaces in a door or dashboard usually include curved or stepped areas where a planar PCB board cannot be directly attached, rather configurations are required so that the board can be supported on the same plane or the board must be broken up into several segments. For the same reason, the use of this type of boards in the ceiling of vehicles, for example in light consoles, is conditioned by the lack of space. So as to not take up usable space, these designs must include deep-drawings to house the board. The rigid casing furthermore takes up a certain volume or thickness, such casing usually being formed by two halves which are joined together, for example, by snap-fitting. The manufacture of both parts and the subsequent assembly, which casing internally houses the PCB, has a relatively high cost. Finally, the weight of the assembly is relatively high, which is a serious problem in the automotive field because weight savings entails fuel savings and reduced pollution.
To solve these drawbacks some vehicles incorporate flexible printed circuits (FPC) on which the corresponding electronic components are assembled. This type of printed boards is implemented on a flexible printed circuit board which is formed by a substrate, which is usually a plastic sheet on which a sheet of metal, such as copper, is deposited, on which sheet of metal the necessary electrical strips or paths are formed by means of etching. Later on a protection sheet is added.
Patent document U.S. Pat. No. 6,088,241-A describes a connection system for automobiles using flexible printed circuit (FPC) technology. This patent document describes a flexible printed circuit board having two parts: a part on which the necessary conductive strips are formed and on which the different active or passive elements, such as integrated circuits, resistors, etc., are formed, and a part without electronic components, on which the conductive strips designed to be connected to the different devices of the vehicle to be controlled are formed. As a result of the flexibility of the flexible printed circuit board (FPC), it is possible to adapt it to the curve of the vehicle door in question. As indicated in U.S. Pat. No. 6,088,241-A, several of these flexible printed circuit boards are manufactured on a single substrate surface, each connection system being separated by means of perforated lines that allow them to be easily separated. To facilitate the coupling to curved surfaces such as that of a vehicle door, the part of the board on which the conductive strips are formed incorporates fold lines that can be folded as needed in order to fold the board and make the end of each conductive strip match up with the device they are going to be connected to and to adapt the assembly to the shape of the door.
However, the connection system provided by U.S. Pat. No. 6,088,241-A has a series of drawbacks: First, incorporating both the part with the electronic components and the conductive connection lines for the connection with the remote devices on the same flexible board entails a huge economic expense, since the manufacture of flexible boards has a high cost. Furthermore, their manufacture may require a specific design for each application since the end of the conductive strips must match up with each device that each of said conductive strips is to be connected to. Additionally, since it is a relatively large board on which as many electronic components as conductive strips are placed, there are frequently problems with the dimensional tolerances of the board and with the position of said electronic components on it. Finally, even though flexible printed circuits (FPC) provide certain capacity to adapt to curved surfaces due to the previously mentioned fold lines, the manipulation that must be carried out to fold them may damage the electronic components, making the board extremely sensitive.
German utility model DE-20116828-U1 describes an electrical connection system connecting several devices or functional areas constructed from a flexible connection board. The system described in DE-20116828-U1 has the same problems as the connector of U.S. Pat. No. 6,088,241-A, since it requires a large flexible board, having a specific design for each application and limited by the dimensions and design of the structure on which it is incorporated, and having a relatively high manufacturing cost.
Flexible flat cables such as those described in EP-1383215-A1, which have been used in the automotive industry, are additionally known.