JP2007165033A - Electric connector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric connector to suppress lowering of the characteristic impedance of a transmission line. <P>SOLUTION: In this electric connector equipped with contacts 12, 14 made of a conductor and resin structures 2, 6 supporting the contacts 12, 14, bubbles 18, 19 are contained in the resin structures 2, 6. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electrical connector that suppresses a decrease in characteristic impedance of a transmission line.

  The electrical connector is a connection member for electrically connecting two electrical members. The side attached to one electrical member is called a plug, and the side attached to the other electrical member is called a receptacle.

  In the case of an electrical connector for electrically connecting a circuit board and a cable, the electrical connector attached to the circuit board is a receptacle, and the electrical connector attached to the cable is a plug. In both the plug and the receptacle, the electrical connector includes a contact made of a conductor and a resin structure that supports the contact. The plug-side resin structure and the receptacle-side resin structure are fitted and mechanically coupled to each other. At that time, the contacts are brought into contact with each other to achieve electrical connection.

  As shown in FIG. 5, the receptacle 51 is obtained by supporting a contact (not shown) on the receptacle-side resin structure 2. In the receptacle-side resin structure 2, leads (not shown) for mechanical connection to the circuit board 3 and electrical connection to the conductor 4 on the circuit board 3 are fixed, and the leads are electrically connected. The contactor is fitted to the resin structure 6 of the plug 55 so as to face the contactor of the plug 55 which is a mating connector.

  On the other hand, the plug 55 is obtained by supporting a contact (not shown) on the plug-side resin structure 6. The plug-side resin structure 6 has a cable holding portion 8 that holds the cable 7, and the contact that is conducted to the conductor (not shown) of the cable 7 faces the contact of the receptacle 51 that is the mating connector. Further, it is adapted to be fitted into the resin structure 2 of the receptacle 51.

  The receptacle-side resin structure 2 and the plug-side resin structure 6 have a variety of shapes because they can be fitted by being complementary to each other such that one has a convex portion and the other has a concave portion. . Here, for simplification, as shown in the drawing, both resin structures 2 and 6 have base portions 2a and 6a having the highest height (in the z direction in the drawing) and a predetermined thickness (in the y direction in the drawing), and their bases. The ribs 2b and 6b are connected to the parts 2a and 6a and have the lowest height and have a predetermined thickness, and the hooks 2c and 6c are connected to the ribs 2b and 6b and have an intermediate height and a predetermined thickness. The length (in the x direction in the figure) assumes a uniform L-shaped cross section.

  As shown in FIG. 6, in the receptacle 51, the lead 11 exposed from the lower surface of the base portion 2a of the receptacle-side resin structure 2 is embedded in the rib portion 2b, and the lead 11 is exposed in the thickness direction from the hook portion 2c. The contact 12 is formed. By soldering the lead 11 to the conductor 4 of the circuit board 3, mechanical connection to the circuit board 3 and electrical connection to the conductor 4 on the circuit board 3 can be achieved. Various structures other than those shown in the drawings are known as the bonding structure between the circuit board 3 and the receptacle 51 and the shapes and postures of the leads 11 and the contacts 12.

  The plug 55 is held by inserting the cable 7 into the round hole-shaped cable holding portion 8 formed in the thickness direction of the base portion 6 a of the plug-side resin structure 6, and the conductor 13 exposed from the cable 7 is held. The conductor 13 penetrates through the base portion 6a and is brought into contact with the contact 14 provided along the side surface of the base portion 6a on the rib portion 6b side (which may be soldered) to be conductive. Various structures other than those shown in the drawings are known as the structure for holding the cable 7 and the shape and posture of the contact 14.

  As a material for the contacts 12, 14 and the leads 11, copper or a copper alloy is preferable, for example, phosphor bronze is used.

  In the receptacle 51, the upper surface and both side surfaces of the base portion 2a are covered with the shield 15. The plug 55 is covered with a shield 16 on the upper surface over the base portion 6a, the rib portion 6b, and the hook portion 6c, the outer side surface of the base portion 6a, and the outer side surface of the hook portion 6c. The material of the shields 15 and 16 is preferably copper or a copper alloy, for example, phosphor bronze.

  As shown in FIG. 7, the receptacle 51 and the plug 55 are fitted by being overlapped so that one rib portion and the other hook portion face each other. At this time, since the contact 12 exposed from the receptacle-side resin structure 2 and the contact 14 along the side surface of the plug-side resin structure 6 are in close contact with each other, electrical connection between both contacts can be achieved. The conductor 13 of the cable 7 and the conductor 4 of the circuit board 3 are electrically connected.

  When the receptacle 51 and the plug 55 are fitted, the shield 15 of the receptacle 51 and the shield 16 of the plug 55 are in close contact with each other. At this time, the shields 15 and 16 are preferably grounded.

  Here, the receptacle-side resin structure 2 and the plug-side resin structure 6 are made of, for example, an LCP (Liquid Crystal Polymer) resin. LCP resin is a general term for polymers having a liquid crystal structure. The LCP resin has a liquid crystallinity (property of molecular chains aligned in the flow direction) and a rigid molecular structure when in solution or when melted. The LCP resin has properties such as high strength, high elastic modulus, high heat resistance and excellent dimensional stability. There is a fully aromatic polyamide as a lyotropic that exhibits liquid crystallinity in a solution state, and an aromatic polyester as a thermotropic that exhibits liquid crystallinity when melted.

  The LCP resin has a temperature of 275 ° C. at which thermal deformation starts. Since this temperature is higher than the melting point of solder (about 260 ° C.), when the lead 11 of the receptacle 51 is soldered to the conductor 4 of the circuit board 3, or the conductor 13 of the cable 7 is soldered to the contact 14 of the plug 55. There is an advantage that heat does not adversely affect the resin structures 2 and 5.

JP-A-6-44831 JP 2000-68006 A JP 2002-352916 A

  When an electrical connector is used for high frequency transmission of 1 GHz to 2 GHz or more, the characteristic impedance at the joint may be a problem. For example, this is the case when the liquid crystal panel of a mobile phone is electrically connected to the main board.

  The characteristic impedance at the junction of the electrical connector will be described with reference to FIG. FIG. 8 is a graph showing temporal changes in characteristic impedance in a transmission line (conductor of circuit board, both contacts, cable conductor) in the vicinity of the electrical connector, with time on the horizontal axis and characteristic impedance on the vertical axis. It is. The temporal change can be regarded as a distribution in the distance direction along the transmission line. That is, the range of the transmission line in the electrical connector shown attached to the graph (the range sandwiched by the alternate long and short dash line) corresponds to a predetermined time range in the graph. This characteristic is calculated with the dielectric constant of the LCP resin as 3.7.

  As can be seen from this graph, the characteristic impedance decreases at the junction of the electrical connector due to impedance mismatch of the transmission line and the like.

  When the relative position of the contact 12 of the receptacle 51 and the contact 14 of the plug 55 shifts, the characteristic impedance changes. Therefore, the resin structures 2 and 6 are rigidly held by the resin structures 2 and 6 so that the contacts 12 and 14 maintain a predetermined position, respectively. It is supported. The resin structures 2 and 6 are obtained by filling the space with resin. That is, the contacts 12 and 14 are fixedly supported by filling the resin around the contacts 12 and 14. The resin is not only an insulator, but also has excellent heat resistance during soldering as described above, and an LCP resin is preferable.

  However, generally, in the resin structure, when the filling rate of resin (ratio of the weight of the resin constituting the resin structure to the volume of the space occupied by the resin structure) increases, the dielectric constant increases. Therefore, also in the electrical connector, when the resin filling rate in the resin structures 2 and 6 increases, the dielectric constant of the resin structures 2 and 6 surrounding the transmission lines such as the contacts 12 and 14 increases, and as a result, the transmission lines The characteristic impedance decreases greatly. When the reduction in the characteristic impedance of the transmission line increases, the reflection coefficient increases, the signal return loss increases, and the transmission performance decreases.

  The conventional electrical connector has a problem that since the filling rate of the resin in the resin structure is high, the characteristic impedance of the transmission line is greatly reduced and the transmission performance is deteriorated.

  Therefore, an object of the present invention is to provide an electrical connector that solves the above-described problems and suppresses a decrease in characteristic impedance of a transmission line.

  In order to achieve the above object, the present invention provides an electrical connector including a contact made of a conductor and a resin structure that supports the contact, in which bubbles are included in the resin structure.

  Bubbles may be contained in the resin structure by generating the bubbles by reducing the pressure when the resin in which the gas is dissolved in advance is formed in the resin structure.

  The resin structure may be configured by mixing a gas-filled micro container in advance with the resin.

  The resin structure has a cable holding portion for holding a cable, and a plug that fits the resin structure of the mating connector with the contact that is conducted to the conductor of the cable facing the contact of the mating connector It may be a side resin structure.

  In the resin structure, a lead for mechanical connection to a circuit board and electrical connection to a conductor on the circuit board is fixed, and the contact connected to the lead is connected to a mating connector. It may be a receptacle-side resin structure that faces the child and fits into the resin structure of the mating connector.

  The present invention exhibits the following excellent effects.

  (1) A decrease in characteristic impedance of the transmission line can be suppressed.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  As shown in FIG. 1, a receptacle 1 according to the present invention is such that a contact 12 is supported on a receptacle-side resin structure 2, and bubbles 18 are included in the receptacle-side resin structure 2. is there. The plug 5 according to the present invention is such that the contact 14 is supported on the plug-side resin structure 6 and the plug-side resin structure 6 includes bubbles 19. The receptacle 1 and the plug 5 have the same structure as the conventional receptacle 51 and the plug 55 shown in FIGS. 5 and 6 except that the bubbles 18 and 19 are included in the resin structures 2 and 6. The explanations made are omitted.

  The manufacturing method of the electrical connector of the present invention will be described with reference to FIG. 2. The heated and pressurized resin 22 flows in the direction of the arrow in the extruder 21. A gas flows into the extruder 21 from a gas inlet 23 inserted into the extruder 21. The gas is a gas having high solubility in the resin, for example, a hydrocarbon. The introduced gas is dissolved in the resin 22. In this way, when the resin 22 in which the gas is dissolved is ejected from the tapered tip of the extruder 21 to the outside of the low pressure, since the resin 22 is decompressed, the dissolved gas is separated and the bubbles 24 are separated. Will occur. In this way, the resin 22 containing the bubbles 24 is filled in the ejection destination. That is, the resin 22 containing the bubbles 24 is filled in the mold for the receptacle 1 and the plug 5, and after solidification, the resin structures 2 and 6 containing the bubbles 18 and 19 are formed. Contacts 12 and 14 and leads 11 are supported on the objects 2 and 6.

  In the present invention, since the bubbles 18 and 19 are contained in the resin structures 2 and 6, the resin filling rate in the resin structures 2 and 6 is low. Therefore, the dielectric constants of the resin structures 2 and 6 are reduced, the decrease in the characteristic impedance of the transmission line is suppressed, and the transmission performance is improved.

  The improvement of characteristic impedance according to the present invention will be described with reference to FIG. The graphs (a) to (c) in FIG. 3 are graphs in which time is plotted on the horizontal axis and the characteristic impedance is plotted on the vertical axis, as in FIG. 8, but the distribution in the distance direction along the transmission line. Can be considered.

  FIG. 3A shows a case where the filling rate of the LCP resin in the resin structures 2 and 6 is made the lowest and the dielectric constant is set to 2 by increasing or increasing the number of bubbles. The characteristic impedance is 69Ω where the characteristic impedance is the lowest.

  FIG. 3B shows a case where the dielectric constant is set to 3 by slightly increasing the filling rate of the LCP resin in the resin structures 2 and 6 by slightly reducing bubbles. The characteristic impedance is 53Ω where the characteristic impedance is the lowest.

  FIG. 3C shows a case where the filling rate of the LCP resin in the resin structures 2 and 6 is the same as that in the conventional case, that is, there is no bubble and the dielectric constant remains 3.7 of the LCP resin alone. The characteristic impedance is 45Ω where the characteristic impedance is the lowest.

  From these comparisons, it was proved that a decrease in characteristic impedance is suppressed by increasing or increasing the number of bubbles 18 and 19 contained in the resin structures 2 and 6.

  FIG. 4 shows the relationship between the dielectric constant and foaming degree of the resin structures 2 and 6 using the LCP resin. Here, the degree of foaming (%) is 100− (resin density after foaming / resin density before foaming) × 100. In the resin structures 2 and 6 having a high degree of foaming, gas components due to the bubbles 18 and 19 occupy a large volume, and the weight of the resin is light. That is, the resin filling rate is low.

  In the embodiments so far, bubbles 18 and 19 are included in the resin structures 2 and 6 by generating the bubbles 24 by reducing the pressure when the resin 22 in which the gas is dissolved in advance is formed in the resin structures 2 and 6. However, in the present invention, since the resin structures 2 and 6 need only contain the bubbles 18 and 19, the manufacturing method may be different. For example, a micro container filled with gas in advance may be mixed into the resin, and the resin structures 2 and 6 may be configured with the gas mixed resin. As the micro container, there is a hollow sphere made of glass.

  In the embodiments described so far, the electrical connector is a receptacle attached to a circuit board and a plug attached to a cable. The invention is applicable.

It is sectional drawing of the electrical connector which shows one Embodiment of this invention. It is sectional drawing of the extruder used for manufacture of the electrical connector of this invention. (A), (b), (c) is a graph which shows the time change of the characteristic impedance in the electrical connector which varied the filling rate of resin. It is a graph which shows the relationship between the dielectric constant of a resin structure in this invention, and a foaming degree. It is a perspective view of an electrical connector. It is sectional drawing of the conventional electrical connector. It is sectional drawing at the time of the fitting of the conventional electrical connector. It is the graph which showed the characteristic impedance distribution of the distance direction along the transmission line of the conventional electrical connector by the time change of the characteristic impedance.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Receptacle 2 Receptacle side resin structure 3 Circuit board 4 Circuit board conductor 5 Plug 6 Plug side resin structure 7 Cable 11 Lead 12, 14 Contact 13 Cable conductor 18, 19 Air bubbles

Claims (5)

  An electrical connector comprising a contact made of a conductor and a resin structure that supports the contact, wherein the resin structure contains air bubbles.   2. The electrical connector according to claim 1, wherein when the resin in which gas is dissolved in advance is formed in the resin structure, the resin structure contains bubbles by reducing pressure to generate the bubbles. .   2. The electrical connector according to claim 1, wherein a micro container filled with gas in advance is mixed into the resin, and the resin structure is constituted by the gas mixed resin.   The resin structure has a cable holding portion for holding a cable, and a plug that fits the resin structure of the mating connector with the contact that is conducted to the conductor of the cable facing the contact of the mating connector The electrical connector according to claim 1, wherein the electrical connector is a side resin structure. In the resin structure, a lead for mechanical connection to a circuit board and electrical connection to a conductor on the circuit board is fixed, and the contact connected to the lead is connected to a mating connector. The electrical connector according to any one of claims 1 to 3, wherein the electrical connector is a receptacle-side resin structure that faces a child and fits into a resin structure of a mating connector.

Images