JP3070359U - Electronic device having terminal pins attached to a flexible substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new and improved system for attaching an electric terminal such as a terminal pin to a flat flexible substrate or a flexible circuit. An electronic device includes a flat flexible insulating substrate having a round hole having a thickness less than 0.050 inches and a given diameter. This insulating substrate 5
A square or polygonal terminal pin 62 is inserted into the 6 round hole 58. The span 64 between the diametrically opposite corners of the terminal pin 62 is greater than the diameter 66 of the round hole 58. The difference between the crossover dimension 64 of the terminal pin 62 and the diameter 66 of the round hole 58 is on the order of 7% to 67% of the diameter 66 of the round hole 58.

Description

[Detailed description of the invention]

[0001]

[Technical field to which the invention belongs]

 The present invention generally relates to electrical connectors, and more particularly, to an electronic device having terminal pins electrically connected to holes in a flat flexible circuit or board.

[0002]

[Prior art]

 Various electrical connectors have been designed for use with flat flexible circuits, where the flexible circuit is attached directly to the connector or is connected to terminal pins on the connector. Generally, a flat flexible circuit includes a flat flexible insulating substrate having one or more holes for receiving one or more terminal pins. An extensible conductive film or other circuit trace is disposed on at least the area around the hole on the insulating substrate. Terminal pins are inserted into holes in the board to establish an electrical and mechanical connection between the pins and the flat flexible circuit. Usually, the diameter of each hole is smaller than each pin. Alternatively, the pins can be driven into a flat flexible circuit to establish electrical and mechanical connections.

[0003] Solder or other adhesives are often used to ensure good electrical and mechanical connection in these types of electronic devices or electrical connectors. For example, in U.S. Pat. No. 4,970,624 issued Nov. 13, 1990, assigned to the assignee of the present invention, a uniaxial adhesive is provided around a hole through which a terminal pin passes in a flat flexible circuit. Is attached. This adhesive incorporates randomly spaced conductive particles into a non-conductive substrate. When the terminal pins are pushed through the adhesive, a portion of the adhesive is carried between the terminal pins and the flat flexible circuit by the terminal pins. This conveyed portion of the adhesive is compressed to establish contact between the conductive particles and, thus, establishes conduction between the terminal pin and the flat flexible circuit, but the adhesive other than that portion remains non-conductive. Will be left. Such adhesives are often referred to as Z-axis adhesives. These adhesives have been developed to replace soldering techniques that require specific high temperature components and substrates.

[0004] Conductive adhesives are also used in other applications involving flat flexible circuits. For example, in U.S. Pat. No. 5,456,616, issued Oct. 10, 1995, assigned to the assignee of the present invention, the connector housing is formed of a die cast metal material such as magnesium or aluminum. The ductile film of the flat flexible circuit is formed of a different metal material, such as copper, and is actually plated with another metal material, such as a tin / lead alloy. The conductive film of the flat flexible circuit acts as a ground plane for the rear surface of the connector housing. The housing has a plurality of pins projecting through holes in the flat flexible circuit. The use of a Z-axis adhesive between the housing pins and the flat flexible circuit is not only expensive as described above, but also limits the conductive interface between the different metal components to the pressurized area. Thus, the patent teaches an omni-directional conductive adhesive that is applied to the conductive film over the area of the hole, where the conductive adhesive is defined by a metal housing and a conductive film. Spread the conductive interface with the ground plane.

[0005]

[Problems to be solved by the invention]

 The use of conductive adhesives, regardless of whether the adhesive is a Z-axis adhesive or an omni-directional adhesive, fulfills their intended purpose in some applications, but the cost of the adhesive and its use Relatively expensive in both aspects of the method. Furthermore, the use of any type of conductive adhesive is expensive in terms of the secondary operations and costs associated with metal particles, and it goes without saying that the metal particles can clog the adhesive applicator.

Due to these problems associated with the use of conductive adhesives, US Pat. No. 5,384,435, issued Jan. 24, 1995, assigned to the assignee of the present invention, has a unique Is disclosed. This patent teaches that conductive adhesives can be made by establishing a direct electrical connection between the terminal pins and the flat conductor of the flat flexible substrate by controlling various parameters between the terminal pins and the flat flexible substrate. Eliminate related issues. In the system of the '435 patent, the terminal pins have a round cross section and the round terminal pins are inserted into the round holes of a flat flexible substrate. Although this system is quite effective, further improvements are still needed and the present invention is directed to this purpose.

For example, a terminal pin having a rectangular cross section improves the strength of the support of the terminal pin, and does not change the pitch between the terminal pins in the connector, that is, the pin in the fitting direction (ie, in the axial direction of the pin). Can be reduced. In other words, such large round terminal pins increase the pitch or spacing between adjacent pins when the diameter of the round terminal pins is equal to the dimension between diametrically opposed corners of the square terminal pins. It is necessary to increase the size of the entire connector. On the other hand, a square terminal pin causes a problem of destroying the hole of the substrate unless a specific dimensional relationship exists between the terminal pin and the round hole of the flat flexible substrate. The present invention is directed to resolving these problems or contradictions.

[0008]

[Means for Solving the Problems]

 Accordingly, it is an object of the present invention to provide a new and improved system for attaching electrical terminals, such as terminal pins, to a flat flexible substrate or a flexible circuit.

According to the present invention, an electronic device includes a flat flexible insulating substrate or circuit having a thickness of less than 0.050 inches. This substrate has a round hole of a given diameter. An extensible conductive film is attached to the substrate at least in the area around the hole. Terminal pins are inserted into holes in the substrate. When the terminal pin is inserted into the round hole, the area around the round hole of the flat flexible insulating substrate is deformed together with the extensible conductive film to form a curved area around the terminal pin, and the curved area is formed. The controllable concave surface defined by the step generates a force perpendicular to the terminal pin to form an electrical connection between the conductive film and the terminal pin. The terminal pin has a rectangular or polygonal cross section, and the cross dimension between diametrically opposite corners is larger than the diameter of the round hole. The difference between the terminal pin passing dimension and the hole diameter is about 7% to 67% of the diameter of the round hole. These parameters establish a good connection between the terminal pins and the conductive film of the flat flexible insulating substrate without destroying the flat flexible insulating substrate.

[0010] The round hole of the flat flexible insulating substrate can be formed in advance. The flat flexible insulating substrate is formed of a material such as polyimide, but other materials such as polyester are also suitable. The extensible conductive film is copper or other conductive thick film material. Both the terminal pins and the extensible conductive film can be plated with a common stick material. In one embodiment, the plating material is a tin / lead alloy.

[0011]

[Embodiment of the invention]

 Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 of the accompanying drawings shows a multi-terminal filter type electrical connector assembly 10 of the present invention. As described in detail below, a pair of flexible capacitor filter circuits 20 are mounted at the rear of the connector 12. The plurality of terminals 22 are assembled to the connector 12 through the flexible capacitor filter circuit 20 when the flexible capacitor filter circuit 20 is pressed onto the pins in the direction of arrow A. Each flexible capacitor filter circuit 20 has a plurality of chip capacitors 21 operatively associated with terminals therethrough. Each terminal 22 includes a tail portion 22a. By way of illustration, FIG. 1 shows a group of terminals 22 held on strip holders 24, which are primarily used to hold terminals 22 during the plating process. Although 16 terminals 22 are only shown in four groups, connector 12 can accommodate 80 terminals 22 and more than 200 terminals 22 in a similarly configured connector design. It can also be installed.

Referring also to FIG. 2 in conjunction with FIG. 1, connector 12 includes a housing 26 having an injection molded insulation insert 28. The housing 26 includes a plurality of through passages 30 for receiving the terminals 22 by the insulating insert 28, whereby the front mating ends of the terminals 22 are exposed to the cavities 32 of the housing 26. The cavity 32 is provided for receiving a complementary electrical connector assembly (not shown) having female terminals that interengage with the terminals 22. The housing 26 defines a rear surface 34, a plurality of mounting pins 36 protruding from the rear surface 34 and inserted into mounting holes 37 of the flexible capacitor filter circuit 20, and mounting the capacitor filter circuit 20 to the rear of the housing 26, Establish electrical contact between the housing 26 and the flexible capacitor filter circuit 20. Housing 26 is preferably a die-cast housing, but can also be made of plated plastic or the like.

With further reference to FIGS. 1 and 2, the connector 12, and particularly the housing 26, is made to form a right angle connector that can be attached to a printed circuit board 38, and the terminals 22 are mounted on the printed circuit board 38. It extends in parallel through the passage 30. The terminal 22 is bent at a right angle at 22b, so that the tail portion 22a of the terminal 22 extends perpendicular to the printed circuit board 38 and is inserted into a suitable hole 42 in the printed circuit board 38, and Interconnected to upper circuit traces or holes. Terminals 22 may also be provided in a straight or vertical orientation to form an in-line or vertical connector attachable to printed circuit board 38.

Referring to FIG. 3, the terminal pins 22 c are inserted into holes 44 of the flexible capacitor filter circuit 20. This system is based on the known technique disclosed in the aforementioned US Pat. No. 5,384,435, in which the hole 44 is round and the terminal pin 22c is round in cross section. The flexible capacitor filter circuit 20 includes a flat flexible insulating substrate 46 having an extensible conductive film 48. The hole 44 is formed in the capacitor filter circuit 20 in advance. The thickness of the flat flexible insulating substrate 46 is less than 0.050 inch. Round terminal pins 22c are inserted into holes 44 to establish an electrical connection with conductive film 48.

The known system of FIG. 3 uses a principle referred to as controlled meniscus, indicated at 50 in FIG. In other words, in order to eliminate the use of solder, adhesives, epoxies, etc., a specific interference is established between the round terminal pin 22c and the flexible capacitor filter circuit 20 in the curved area 50, Reference numeral 50 denotes a deformed peripheral region of the flexible capacitor filter circuit 20, which applies a force perpendicular to the direction of arrow C to the terminal pin 22c when the terminal pin 22c is inserted in the direction of arrow D. It has been found that this area 50 and interference force is controlled by controlling the relative diameter of the round terminal pin 22c and the round hole 44. In practice, it has been found that a good electrical connection can be maintained when the difference between the diameter of the terminal pin 22c and the diameter of the hole 44 is on the order of 5% to 50% of the diameter of the hole. This is called an interference parameter.

The known system of FIG. 3 performs secondary tasks such as soldering terminal pins to the flat conductors of a flat-flexible circuit or using epoxy or other adhesive between the terminal pins and the flexible circuit. It shows that it can be completely eliminated and that a good electrical connection can be maintained between the terminal pins and the flat conductor (film) of the flexible circuit. However, the present invention provides further improvements to these concepts, as shown in FIG.

More specifically, it has been found that the post strength of the terminal pins can be significantly increased by using a square terminal pin without increasing the pitch or spacing between the terminal pins. However, square terminal pins conventionally pose the problem of cracks in the square corners due to the terminal pin geometry relative to the hole diameter and the alignment between them. The present invention solves this problem in the system described below. FIGS. 4 and 5 show an electronic device 52 that can be applied with terminal pins of a connector 12, such as the electrical connector assembly 10 of FIGS. Also in this system, the flat flexible circuit 54 includes a flat flexible insulating substrate 56, which has a round hole 58 and an extensible conductive film 60. A rectangular terminal pin 62 is inserted into the hole 58 of the flat flexible insulating substrate 56 to establish an electrical connection with the conductive film 60. The square terminal pin 62 has a cross dimension between the diametrically opposed corners greater than the diameter of the hole 58. More specifically, the difference between the span of the square terminal pin 62 and the diameter of the round hole 58 is on the order of 7% to 67% of the diameter of the hole 58.

The above relationship is best illustrated in FIG. 5, in which the span between the diametrically opposed corners of the square terminal pin 62 is indicated by a double arrow 64. The diameter of the round hole 58 of the flat flexible substrate 56 is indicated by a double arrow 66. Therefore, the difference between diameter 64 and diameter 66 is on the order of 7% to 67% of diameter 66. These parameters represent a controlled meniscus, indicated at 68 in FIG. 4, and the deformed periphery of the flat flexible circuit 54 when the square terminal pin 62 is inserted in the direction of arrow F. The region applies a force perpendicular to the direction of arrow E to the terminal pin 62 having a square shape.

The interface between the conductive film 60 and the terminal pins 62 may be made of the same material or different materials. For example, the conductive film 60 is copper and the terminal pins 62 are plated with tin or a tin / lead alloy. The copper film itself can be plated with a tin / lead alloy, and the terminal pins 62 can be plated with a similar tin or tin / lead alloy to form a similar metal interface, or the terminal pins 62 can be plated with a similar metal interface. Different metals can be plated. Of course, other alloys such as nickel could be used. The flat flexible insulating substrate 56 may be made of various materials such as polyimide and polyester materials. Also, the corners of the terminal pins 62 can be rounded to further eliminate destruction of the flat flexible insulating substrate 56 due to alignment problems associated with assembling the flat flexible circuit 54 and the connector 12.

[0020]

[Effect of the invention]

 As is apparent from the above description, the present invention provides a new and improved electronic device for attaching an electric terminal such as a terminal pin to a flat flexible insulating substrate or a flexible circuit.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a multi-terminal filter type electrical connector assembly of the present invention.

FIG. 2 is an enlarged vertical sectional view showing a state where the electrical connector assembly is mounted on a printed circuit board.

FIG. 3 is an enlarged sectional view showing an interconnection between a terminal pin and a flat flexible circuit according to a known technique.

FIG. 4 is an enlarged cross-sectional view showing the interconnection between the terminal pin and the flat flexible circuit according to the present invention.

FIG. 5 is a sectional view taken along line 5-5 in FIG. 4;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Electric connector assembly 12 Connector 20 Capacitor filter circuit (flat flexible circuit) 21 Chip capacitor 22 Terminal 22a Tail part 22c Terminal pin 24 Strip holder 26 Housing 28 Insulation insert 30 Penetration path 32 Cavity 36 Mounting pin 37 Mounting hole 38 Printed circuit board 52 Electronic device 54 Flat flexible circuit 56 Flat flexible insulating substrate 58 Round hole 60 Extensible conductive film 62 Terminal pin

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Harry N. Eters United States Illinois Plainfield Primrose Circle 24142 (72) Inventor Robert M. Faith United States Illinois Maple Park Landrose Lane 2N 625 (72) Inventor Todd A Hoster United States Montgomery Fox Mead Circle, Illinois United States 1750 (72) Inventor Fred Love Krebier United States Chicago, Illinois Unite 9 North Lasin 2222

Claims (14)

[Utility model registration claims] 1. A flat flexible insulation having a thickness of less than 0.050 inch and having a round hole 58 of a given diameter and an extensible conductive film 60 at least in the area around said hole 58. And a terminal pin 62 inserted into the round hole 58 of the flat flexible insulating substrate 56. When the terminal pin 62 is inserted into the round hole 58, Is deformed together with the extensible conductive film 60 to form a curved area around the terminal pin 62, and a force at right angles to the terminal pin 62 by the controlled concave surface 68 defined by the curved area. In the electronic device, the electrical connection is formed between the conductive film 60 and the terminal pin 62, The crossover dimension 64 between the diametrically opposed corners is made larger than the diameter 66 of the round hole 58, and the crossover dimension 64 of the square terminal pin 62 and the crossover dimension of the round hole 58 are formed. An electronic device characterized in that the difference between the diameter 66 and the diameter 66 is about 7% to 67% of the diameter 66 of the round hole 58. 2. The flat flexible insulating substrate 56
The electronic device according to claim 1, further comprising an extensible conductive film in at least a region around one side surface of the hole. 3. The electronic device according to claim 1, wherein the corners of the square terminal pins are rounded. 4. The electronic device according to claim 1, wherein the square terminal pins are plated with a conductive material. 5. The electronic device according to claim 1, wherein the square terminal pins are plated with a tin / lead alloy. 6. The flat flexible insulating substrate 56
The electronic device according to claim 1, wherein the electronic device is formed of a polyimide material. 7. The flat flexible insulating substrate 56
The electronic device according to claim 1, wherein is formed of a polyester material. 8. The flat flexible insulating substrate 56
The electronic device according to claim 1, wherein the hole 58 is a hole formed in advance. 9. A flat flexible insulation having a thickness of less than 0.050 inches and having a round hole 58 of a given diameter and an extensible conductive film 60 at least in the area around said hole 58. And a terminal pin 62 inserted into the round hole 58 of the flat flexible insulating substrate 56. When the terminal pin 62 is inserted into the round hole 58, Is deformed together with the extensible conductive film 60 to form a curved area around the terminal pin 62, and a force at right angles to the terminal pin 62 by the controlled concave surface 68 defined by the curved area. In the electronic device, the terminal pins 62 are formed to have an electric connection between the conductive film 60 and the terminal pins 62. Square terminal pins 62,
The crossover dimension 64 between the diametrically opposed corners is greater than the diameter 66 of the round hole 58, and the difference between the crossover dimension 64 of the polygonal terminal pin 62 and the diameter 66 of the round hole 58. Is about 7% to 67% of the diameter 66 of the round hole 58. 10. The electronic device according to claim 9, wherein the corners of the polygonal terminal pin 62 are rounded. 11. The flat flexible insulating substrate 5
The electronic device according to claim 9, wherein the electronic device includes an extensible conductive film in at least a region around one side surface of the hole. 12. The electronic device according to claim 11, wherein the extensible conductive film 60 and the terminal pins 62 are plated with a common conductive plating material. 13. The electronic device according to claim 9, wherein the terminal pins are plated with a conductive plating material. 14. The electronic device according to claim 13, wherein the terminal pins are plated with a tin / lead alloy.