As the density of circuitry on cards and boards increases, thus increasing the density of connections necessary, the distance between adjacent pads as well as the size of the pads becomes smaller, thus requiring increasingly precise alignment of the connectors which contact the connecting pads. One of the present technologies used for making connections to pads on boards and cards is by utilizing flexible circuit with various flexible circuit mounting technologies. In certain instances, this precision can be accomplished by precise positioning during factory assembly of a single board to a single card or assembling flexible circuit precisely on a single card or a limited number of cards using alignment fixtures and the like.
However, for certain connection functions precise alignment is difficult to achieve. One instance where precise alignment is difficult to achieve in which high density pad-to-pad connections are required is in the "plugging in" of I/O cards on computers. In particular, I/O cards are inserted into I/O card slots provided for this purpose in computers, especially personal computers, wherein the I/O card joins with the planar or mother board. This is sometimes referred to as a card-to-board interconnection or daughter card to mother board interconnection. This type of card-to-board connection is called a "blind" connection since there is no eye or other instrument to "see" how the alignment of the pads is matching up. In such instance, the card is slid into the slot, and at the end of the slot, the connector pads on the mother board are connected by flexible circuit technology to connector pads on the daughter card. With conventional prior art practices of pin and hole connections (as opposed to flexible circuit technology), the connection would, to a great extent, be self-aligning in that the pins would physically plug into the holes. However, with present day technology utilizing pad-to-pad connection, i.e., connecting pads on flexible circuit in compressive engagement with pads formed on the mother board, there is no such "self-aligning" feature available. Hence, during the insertion process, alignment of the daughter card has to be maintained relatively precisely so that the proper pads on the flexible circuit which forms a portion of the connector properly align with the pads on the board to which connections are to be made. With relatively less dense array in which the pads are relatively larger, an appreciable amount of mismatch can be tolerated. However, miss alignment poses an ever increasing problem with the ever increasing density of pad connections without self-aligning features.
Other instances wherein precise alignment is difficult or tedious to achieve include those where a series of cards or family of cards is to be interconnected, e.g., in a parallel configuration, where the cards are to be connected serially back-to-front in adjacent positions. In these instances, precise alignment often can be obtained by hand by an operator precisely aligning the components. Nevertheless, it is time-consuming and, as the number of cards in the stack increase, the time necessary for precise alignment increases and the precise alignment becomes more difficult.