Method and Arrangement for the Connection of a Multipole Connector to a Circuit Board

The invention relates to a method and apparatus for coupling the terminals of a multipole connector to a circuit board.

Up until now, connectors, for example 96-pole connectors or the like, have usually been coupled to circuit boards by soldering the connector terminals to plated through holes in the circuit board. However, new surface connection techniques give rise in particular to the problems discussed below for the connection of such connectors. The bonding of electronic components and the like may be carried out by a type of bonding known as "surface mount" by means of so-called gull wings or "J" wings, not requiring any wave soldering; instead, soldering is performed by a reflow of soldering paste which has been previously deposited. If the customary form of hole bonding is utilized for the connection of a normal connector, this gives rise to the necessity, which is undesirable from the production point of view, that a so-called solder wave is required just for the connector terminals. This is obviously undesirable in a manufacturing process.

In order to avoid wave soldering, it has already been proposed to attach the connectors mechanically, for example by riveting, in the edge region and to allow the terminals to rest more or less freely, with just a slight contact pressure, on the intended contact points of the circuit board and to carry out bonding by the reflow solder method. However, this may also entail difficulties in that the many contacts do not necessarily rest with precisely the same preload pressure on the intended contact points. For instance, it is possible that one metal lead rests on its contact point with a relatively high pressure and another is not in contact at all, so that absolute contact reliability cannot be insured. If, on the other hand, the terminals of a multipole connector are provided with a certain resilient preload, it may easily happen that the circuit board is distorated slightly by the preload pressure exerted by the terminals, for example by 0.3 to 1 mm. This means that the desirable easy insertion of a circuit board into its intended position is no longer guaranteed.

The invention is therefore based on the desire of creating a means of connection for connectors which makes it possible to couple the connector to a circuit board by the solder reflow method, in other words without wave soldering, but nevertheless to guarantee a reliable connection and ensure a force-free tolerance compensation for the position of the connector terminal ends.

The method according to the invention for the connection of a multipole connector, preferably to the edge region of a circuit board utilizes a plurality of blind holes which do not extend completely through the circuit board and which are equivalent in number to and matching the location of the terminals extending out of the connector housing. The blind holes are filled with solder paste, the connector housing is positioned relative to the circuit board in such a way that the free ends of the terminals project into the blind holes, and the mechanical and electrical connection of the terminals to the circuit board is carried out by a reflow soldering method.

The main advantages of the type of connection according to the invention compared with the conventional technique utilizing plated through holes which extend completely through the circuit board may be briefly summarized as follows:

1. Conductor paths may be routed on the bottom of the circuit board underneath the blind holes.

2. The solder paste cannot escape from the bottom of the blind holes; rather, a sure supply of solder and thus satisfactory bonding is insured.

3. Compared with the customary surface mount terminals (gull wings or "J" wings), a greater tolerance range of the lengths of the terminals is possible without subjecting the circuit board to preload forces, which is particularly advantageous in the case of large multipole connectors.

It is accordingly an object of the invention to provide a terminal connection arrangement between a multipole connector and a circuit board characterized in that the circuit board is provided with a plurality of blind holes, equivalent in number to and matching the location of the terminals extending out of the connector housing wherein the ends of the terminals project into the blind holes and are soldered by a reflow soldering technique.

An exemplary embodiment of the invention will be explained in more detail below with reference to the drawing figure.

The FIGURE shows an end view, partly in section, of a terminal connection arrangement between a multipole connector adn a circuit board according to the invention.

The FIGURE shows a connector housing 2 which is mated to the edge region of a circuit board 1 (positively fitted in the example shown). Protruding laterally from the connector housing 2 in the example shown are three rows of terminals 4, which are bent downwardly in the direction of the circuit board as shown. The circuit board 1 is provided with a plurality of blind holes 3 equivalent to the number of terminals 4. Each of the blind holes 3 contains a quantity of soldering paste 5. The connector housing is mounted in the correct position on the circuit board 1, so that the free ends of the bent terminals 4 project into the blind holes 3. The free ends of the terminals 4 can be soldered together with all other electronic and electrical components and modules (not shown) on the circuit board 1 using the reflow solder method.

From a manufacturing point of view, the invention offers clear cost advantages and ensures a reliable mechanical and electrical connection between the circuit board 1 and connector housing 2 without any fear of the circuit board being deformed, since the free ends of the terminals 4 project into the blind holes 3 but are not required to exert a preload force on the circuit board.

Having thus described the invention, various alterations and modifications will be apparent to those skilled in the art, which alterations and modifications are intended to be within the scope of the invention as defined by the appended claims.