CA1132213A

CA1132213A - Printed circuit board connector

Info

Publication number: CA1132213A
Application number: CA347,672A
Authority: CA
Inventors: Matthew Pobog
Original assignee: GERMAR INDUSTRIAL GROUP
Current assignee: GERMAR INDUSTRIAL GROUP
Priority date: 1979-04-02
Filing date: 1980-03-14
Publication date: 1982-09-21
Also published as: FR2453509B1; DE8008351U1; KR830002411A; DE3011744A1; GB2048582B; DE3011744B2; FR2453509A1; KR830001556B1; DE3011744C3; GB2048582A

Abstract

SPECIFICATION
FOR
PRINTED CIRCUIT BOARD CONNECTOR
BY
MATTHEW POBOG

ABSTRACT

A resilient, flexible, insulative substrate with an insulative adhesive on a major surface has a plurality of conductors arranged in mutually spaced relationship on the adhesive surface of the substrate. The spacing of the conductors is such as to permit aligning and contacting conductive pads on a printed circuit board or other apparatus to which interconnection is to be made. The conductors include a conductive adhesive on the outer surface for securing with the pads. In use, part of the connector is pressed onto the edge of the printed circuit board so that the conductors are adhesively interconnected one-for-one to the pads on the board. The remainder of the connector is then pressed onto terminals of, say, another board or other electrical circuits or equipment.

Description

~32Z~3 The present invention relates generally to an electrical connector, and, more particularly, to an electrical connector for making connection to flat-surfaced contact areas such as are found on printed circuit boards, liquid crystal displays and the like.

BACKGR UN OF THE INVENTIOI~

A long-standing and difficult problem in the electronic fabrica.tion art has been t.hat of effecting interconnections to a printed circuit board or a liquid crystal display, where the interconnections are able to withstand the shocks and vibrations encountered during manufacture and use. A printed circuit board typically includes an insulative base or substrate on which are mounted various electrical and electronic components, all inter-connected by wires and~or deposited leads on the substrate. .
Terminals for interconnecting the printed circuit board with other apparatus conventionally consist of a plurality of flat-. surfaced, deposited pads or lands formed along one or moreedges of the board.
:::
Prior connectors for making interconnection with the terminals of such board.s have consisted of metallic spring-like members clamped onto the circuit board edge margin effecting contact with the terminal pads through spring action.
These spring metal connectors have not been completely - ~ ' illi~
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~l~32~:~3 satisfactory from several standpoints, the first o~ which being that they tend to develop loose connections with the terminal pads. This is primarily the result of the relatively low amount of spring pressure that has to be used per contact since such connectors usually include means for providing a large number of individual connections (e.g., as many as 40 is not uncommon). That is, to keep the total magnitude of the connector insertion force within a manageable range, the sprina pressure of each contact must be kept low. Not infrequently, one or more of the connector spring contacts becomes bent during fabrication or assembly resulting in either failure to connect or the creation of a "high-resistance"
connection, both of which are undesirable.

In an effort to insure the achievement of yood and ` reliable connection using a spring connector, these connectors are sometimes secured in place through the use of an epoxy or other suitable adhesive material. However, when this is done, the connectors cannot be removed without substantial risk of destroying the connector, the board, or both.

;~ SUMMARY OF THE INVENTION
_ _ "

The connector of this invention includes a resilient, flexible, insulative base or substrate having an insulative adhesive on a major surface thereof. A plurality of conductors are arranged in mutually spaced relationship on the adhesive , . :

~3,'Z2J~3 surface of the resilient substrate. The conductors are of predetermined arrangement to permit individually contacting a corresponding number of terminal pads on, say, a printed circuit board to which interconnection is desired to be made.
~ The material forming the conductors preferably includes an electrically conductive adhesive incorporated therein for providing conductive securement between the conductors and terminal pads. Optionally, the conductive adhesive may be applied as a separate coating or film onto the conductors.

In use, part of the connector is pressed onto the edge of the printed circuit board so that the conductors thereof are adhesively interconnected one-for-one to the terminal pads on the board. The remainder of the connector is then pressed onto another set of terminal pads of, say, another board, other electrical circuits of equipment, or other components.

DESCRIPTION OF THE DR~WING
~` . .
Figure 1 is a perspective view of a connector of this invention shown interconnectino a circuit board to other apparatus.

~; ~igure 2 is an enlarged plan view of a connector made in accordance with this invention.

,. . ..

, ~32Z~3 Figure 3 is a sectional, elevational view taken along the line 3-3 of Figure 1.

Figure 4 is a perspective view of the connector formed into a roll.

Figure 5 shows a connector strip removed from the roll of Figure 4.

Figure 6 is a sectional, elevational view taken along the line 6-6 of Figure 5.
.,; ' `' ' :
` 15 DESCRIPTION OF PREFERRED EMBODIMENTS

With reference now to the drawings, and particularly Figure 1, a printed circuit board to which interconnections are to be effected in accordance with the subject invention ~ is identified generally as at 10 and is seen to include J~ generally a rectangular insulative base 11 on which a ;~ microcircuit. discrete components or the like represented :~ schematically as at 1~, are mounted and interconnected in accordance with he circuit desired. The printed circuit board 10 is conventionally interconnected with other circuit boards or other electrical apparatus via terminals arranged along the board edge margin and consisting of a plurality of deposited, flat-surfaced conductive pads 13. ~hese pads or ' . . , - . . ":, :., , ~13;~

lands can be formed in a number of known ways such as, for example, sil~screenina and vacuum deposition. The base or substrate 11 can be constructed of glass, ceramic or other good insulative material posses,ing sufficient rigldity to serve as a circuit base. Although interconnections may be accomplished between the printed circuit board 10 and other electrical apparatus of great variety, for convenience, the connector of this invention will be described as effecting connections with liquid crystal display 14 on which the lo board 11 rests, which display has a set of connection pads 15 on one of its edges of respective spacing the same as that of pads 13. It is to be noted that the circuit board pads 13 are on a different level from the liquid crystal display pads 15 with a right ar.gle s~ep or shoulder 16 therebetween.

~ 15 3 -`
With reference no~ additionally to Figure ~, the connector 17 includes a generally rectangular strip 18 of insulative material which is highly flexible and resilient as, for example, a woven textile material. On a major surface of the strip 18 there is provided an insulative adhesive layer~ldentlfled as at 19. A plurality of elongated, generally parallel conductors 20 are arranged to extend completely across the narrow width of the strip in mutually spaced relatior,ship. Preferably, the conductors 20 are conductive, adhesive and flexible so that, as will be more particularly shown later, in use the entire connector may be flexed or formed about a sharp corner or be submitted to wide range of deEormations without destroying or substantially .

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impairing the conductive characteristics of the conductors.
That is, it is preferred that the conductors 20 be constructed of a material that incorporates a conductive adhesive that form the desired adhesive film~21 on the outer surface when the conductor is laid down on the strip 18.

Optionally, conductors 20 may be separately coated with a conductive adhesive to form the adhesivé coating or film 21.

In use, the described connector is laid onto the printed circuit board 11 with a portion of the connector overlying the set of terminal pads 13. Pressure is then applied onto the connector so that the conductors 20 adheringly contact corresponding pads and the insulative adhesive 19 : secures the suhstrate 18 to the non-conductive board 11 lyinq between and adjacent to the pads 13. The connector . is then shaped to fit into the corner 16 adheringly contacting the edge of the board 11 and immediately adjacent parts of 14.
Finally, the remainder of the connector 17 is pressed into contact with the pads 15 on the display 14 thereby providing the desired interconnection between respective pairs of pads 13 and 15. When in final operative relation, as shown ~: in Figures 1 and 3, the connector is anchored in position over the pads and adjacent insulative portions of the boards 11 : and 14 thro~lgh combined effect of the insulative adhesive 19 and the concluctive adhesive 21. If it becomes necessary to remove the connector, it can be simply peeled off with no ,~ .

: -7-Z21.3 deleterious effect to either the underlying pads or the bc,ards, and the same connector or a new one may be applied as before.

Although other materials may be found useful, it is considered that a cloth or other woven textile is best for constructing the connector substrate 18 in that repeated and extreme bending or deformation does not destroy it; and it also does not have a memory (as certa n plastic materials do) which could provide so-called "creep" tending to break electrical connections completely or form an undesirable high-resis'ance connection. An alternative material which may be found suitable for this purpose is a plastic, such *
~ ~ as Mylar, which is resilient and can be readily coated with ~; ., ` 15 adhesives.
;' .
- An excellent material for making the conductors 20 that nas both the qualities of conduction and conductive adhesiveness, is a silver filled polymer manufactured and sold by Emerson & Cuming, Inc. of Canton, Massachusetts 02021.

This conductive adhesive has good qualities of conduction, is both resilient and flexible and maintains a surface tackiness or conductive adhesive property after setting up for purposes already described. Using this material, the conductors may be formed in any number of different ways, such as by silk-screening, brushing, roller coating' spraying, or dipping, all of which are well-known production techniques. It is important to emphasize that conductors formed by this material ~ , , ' : ' . - -' .'' ~ ', ~

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are highly flexible permitting substantial deformation of the final product carrying conductors made therefrom without destroying the conductors or causing separation of the conductors from the substrate on which they are laid.

As an alternate, there is a silver paint sold by Micro-Circuits Company of New Bu~falo, Michigan, under the trade designation SC18-0.04 consisting of silver particles suspended in a resilient rubber carrier which can be used to make the conductors 20. ~ resilient conductive epoxy made commercially available by Micro-Circuit Company of New Buffalo, Michigan, can be applied directly over these conductors to form the desired conductive layer, coating or film 21.

There is provided in accordance with the practice of the present invention, a connector which establishes interconnection between terminals quickly and easily, and is inexpensive and simple to manufacture. It is also an advantage of the described connector that it easily conforms to surface or object irregularities, or relative arrangements of the circuit apparatus to be interconnected without requiring change in the shape, conctruction, or manner of operation of the connector. For example, if it should be desired that two circuit boards to be interconnected should be arranged ; 25 at 90 to one another, the same connector strip could be used, the inherent flexibility and resilience of the strip easily accommodating the 90 flex without suffering any impairment of function or operation.

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Although as described above, the connectors 17 can be made individually according to the final size desired, it is also contemplated that the connector strip may be made ln the form of a large rectangular sheet 22 with the conductors e~tending parallel to the long edges, and when it is desired to provide an individual connector, the desired amount of connector may be merely cut off the end of the sheet tFigure 4).
The sheet 22 may also be formed into a roll 23 for storage and ease of use, if desired. Preferably, the sheet would include an insulative protective layer 24 provided over the conductors and peeled off when the connector is to be used.

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Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A multiple lead connector of a certain length selected to interconnect corresponding spaced pairs of relatively flat conductive pads, comprising:
a flexible extent of an insulative material having a flat surface;
a plurality of flexible conductors adhered to the flat surface of said insulative material in mutually spaced relation and running the complete length of said connector;
an insulative adhesive adheringly contacting the insulative material between the flexible conductors running the full length of said connector and forming a continuous mass of insulative adhesive between adjacent conductors; and stripes of conductive adhesive material arranged in respective one-on-one continuous covering relation to each conductor and running the complete length of said conductors, said stripes being further arranged mutually spaced and said insulative adhesive extending between and substantially filling the intervening spaces between adjacent flexible conductors.

2. A multiple lead connector as in claim 1, in which said conductive adhesive material is a conductive epoxy.

3. A multiple lead connector as in claim 1, in which there is further provided a removable protective layer adhered over the conductors and peelable therefrom prior to use.

4. A multiple lead connector as in claim 1, in which the conductive adhesive stripes and the insulative adhesive have outwardly directed surfaces that are substantially coplanar.

5. A pressure operated electrical connector of a certain length selected to interconnect a plurality of respective paired spaced electrodes, comprising:
a flexible insulative strip having a generally smooth surface;
a plurality of elongated flexible mutually spaced conductors adhered to the insulative strip smooth surface running the entire length of the connector; and an adhesive covering the outwardly directed parts of the flexible conductors and insulative strip smooth surface between said conductors in a continuous manner forming a substantially planar surface running the entire length of said connector, the adhesive outwardly opposite the conductors being electrically conductive and the adhesive outwardly opposite the insulative strip surface between conductors being electrically insulative between adjacent conductors, the insulative adhesive adheringly contacting the strip smooth surface between the conductors and lateral portions of the conductors.

6. An adhesive tape-like connector of a certain length selected for making bonded electrical connections between spaced conductive terminal pads, said connector comprising:
a plurality of electrically conductive flexible stripes running the entire length of the connector;
and an electrically insulating web supporting and holding the electrically conductive stripes in spaced electrically insulated relation; at least the outer layer of said electrically conductive stripes comprising an electrically conductive adhesive running the entire length of said stripes by which the stripes can be conductively bonded to a substrate at all points along the length of the stripes.

7. A connector as in claim 6, in which said electrically conductive stripes comprise a conductive layer and a layer of conductive adhesive coated over the conductive layer.

8. A connector as in claim 6 or 7, in which an insulative adhesive fills the space between adjacent electrically conductive stripes.

9. A connector construction for interconnecting spaced pairs of relatively flat conductive terminal lands, comprising:
a flexible insulative sheet; and a plurality of parallel spaced conductors deposited onto said insulative sheet, said conductors being constructed of a material making the outer surface of the conductors conductively adhesive.

10. A connector as in claim 9; in which there is further provided an insulative adhesive layer on the insulative sheet surface between the conductors, said insulative adhesive substantially filling the spaced between adjacent conductors.

11. A connector and cable construction for interconnecting first and second spaced pairs of relatively flat conductive terminals, comprising:
a flexible insulative sheet of generally rectangular construction, a first pair of parallel edges having a spacing at least equal to the spacing of said first and second pairs of conductive terminals;
a plurality of mutually spaced substantially parallel conductors deposited on a major surface of said insulative sheet and extending between said first pair of sheet parallel edges;
a stripe of conductive adhesive over the outwardly directed surface of each conductor, each said stripe being spaced from adjacent stripes and extending continuously along a conductor for the complete length of said conductor; and insulative adhesive on said sheet between the conductors and conductive adhesive stripes, said layers substantially filling the spaces between adjacent conductors.

12. A connector and cable construction as in claim 11, in which the insulative sheet is constructed of Mylar.

13. A method of making a connector and cable construction for use in interconnecting first and second pairs of relatively flat conductive terminals, comprising the steps of:
forming a rectangular sheet of a flexible insulative synthetic plastic material having a major surface;
depositing a plurality of conductive stripes on the major surface of the sheet in mutually spaced relation and extending continuously between two parallel edges of said sheet; and covering at least part of the width of each conductive stripe throughout the full length of the conductive stripe with a conductive adhesive.

14. A method as in claim 13, including the further step of filling the spaces between adjacent conductive stripes with an insulative adhesive.