Electricity: conductors and insulators – Insulators
Reexamination Certificate
2001-09-27
2003-05-27
Reichard, Dean A. (Department: 2831)
Electricity: conductors and insulators
Insulators
C174S13800J, C174S14900R, C174S176000
Reexamination Certificate
active
06570097
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to connectors, and more particularly, to a connector suitable for high-speed signal circuits in which crosstalk is inhibited and impedance matching can easily be established.
2. Related Art
In recent years, as electronic information devices grow more sophisticated, the rate of signals treated with electronic circuits is increasing very rapidly. Moreover, circuits are being densified and integrated, and a distance between signal lines is being shortened. Because of such increase in the rate of signal transmission and miniaturization of devices, to secure packaging technology and wiring technology which can control noises and delay is increasing in importance to such an extent that it becomes a governing condition of the whole system.
In light of such a present situation, there have been made a variety of suggestions for dealing well with high-speed, high-density signal circuits also in the field of connectors. What is important for connectors for high-speed, high-density signal circuits is crosstalk control and impedance matching. Crosstalk is a failure associated with an electromagnetic behavior of signals in a high-frequency circuit and refers to a phenomenon that signal lines arranged side by side interfere with each other. With reduction in a distance between signal lines resulting from densification of a circuit, the crosstalk control is becoming an important challenge. Impedance matching refers to a procedure to cause signal circuits mutually connected to have a predetermined impedance (usually standardized at 50 &OHgr;, 75 &OHgr; or 90 &OHgr;) since if the circuits have impedances mismatched, reflection of signals and the like will occur at connecting portions thereof. To reduce an electrical transmission efficiency or to control the generation of reflected waves by establishing impedance matching is becoming an important challenge for achieving the increase in signal transmission velocity (the increase in frequency). Moreover, impedance mismatching itself will cause crosstalk.
As means for solving such problems, Japanese Patent Laid-Open No. 243936(1994) discloses a composition wherein an earthed conductor is disposed between signal terminals. In such a composition, however, a connector structure becomes complicated and its applicable range will be restricted. Japanese Patent Laid-Open No. 96814(1994) provides means for ensuring impedance matching by adjusting the area of the main body parts of terminals. This approach is unique as an impedance matching method, but is not suitable for a small production because to design the optimum shape requires the adjustment involving the change of a mold. Japanese Patent Laid-Open No. 162227 (1996) proposes to adjust the area facing the adjoining contact to reduce impedance, thereby adjusting it. This approach, however, can not deal with those having impedances lower than the predetermined impedances due to limitations in design.
Japanese Patent Laid-Open No. 215819(1994) discloses means for establishing impedance matching by reducing impedance through providing, to paired conductor portions, such plane parts that can be given predetermined capacitances. However, also this approach requires much labor to form conductor portions of special shapes and the designing of the shapes of the plane parts is difficult.
Other various suggestions have been made in this technical field, but any means sufficiently simple and effective is not known, yet.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a connector which can match impedances easily and a method for matching the impedance of a connector.
The connector of the present invention is that comprising an insulator and two or more conductor portions provided side by side within the insulator. The insulator is characterized by being formed of a composition obtained by incorporating, to a matrix resin, 5 to 85% by weight of a ceramic dielectric powder having a dielectric constant of 30 or more determined at 25° C. and 1 MHz.
In the present invention, the dielectric constant, determined at 25° C. and 1 MHz, of the resin composition constituting the insulator is preferably 5 to 20, and more preferably 7 to 15.
Moreover, in the present invention, it is preferable that the insulator is substantially homogeneous in the dielectric constant throughout the insulator.
The method for impedance matching of the present invention is that in which the impedance of an impedance matching-type connector is matched and is characterized by constituting the insulator of a connector by using a resin composition having a dielectric constant of 5 to 20 determined at 25° C. and 1 MHz.
The resin composition constituting the insulator of the present invention is that obtained by incorporating, to a matrix resin, 5 to 85% by weight of a ceramic dielectric powder having a dielectric constant of 30 or more determined at 25° C. and 1 MHz.
The matrix resin can be selected appropriately from various kinds of thermoplastic resins and thermosetting resins. However, from the viewpoints of moldability, heat resistance and mechanical strength, desirably used are polycarbonate resin, polyethylene terephthalate resin (PET resin), polybutylene terephthalate resin (PBT resin), polyamide resin such as polyamide 46, polyamide 6T, polyamide 6/6T, polyamide 6, polyamide 66, polyamide 11 and polyamide 12, polyphenylenesulfide resin, polyethersulfone resin, poly 1,4-cyclohexane-dimethylene-terephthalate resin (PCT resin), polyamideimide resin, polyphenylene ether resin (including polyphenylene oxide or the like), modified polyphenylene ether resin, polyphenylene ether resin including alloy resin made of polyphenyl ether resin and polyetherimide resin, polystyrene resin (particularly, syndiotactic polystyrene resin is preferred), 5-methylpentene resin, cyclic polyolefin resin, heat resistant ABS resin, aromatic polysulfone resin, polyether imide resin, polyether ketone resin, polyether ether ketone resin, polyether nitrile resin, thermotropic liquid crystal polyester resin (LCP), melt-resistant fluororesin, thermoplastic polyimide resin and the like.
Furthermore, the thermosetting resins are exemplified by triazine resin, thermosetting polyphenylene ether resin, epoxy resin and the like.
These resins can be used alone or after the mixing of two or more of them.
As the ceramic dielectric powder having a dielectric constant of 30 or more determined at 25° C. and 1 MHz (this may, hereinafter, be referred simply to as “a ceramic dielectric powder”), there can be employed powders of various kinds of ceramics known as ferroelectrics typified by divalent metal salts of titanic acid typified by alkaline earth metal titanates such as barium titanate, lead titanate, strontium titanate, calcium titanate, barium-strontium titanate and barium-calcium titanate; metal zirconates such as barium-lead zirconate and lead zirconate; vanadic acid compounds such as sodium vanadate; metal niobates such as sodium niobate, potassium niobate, lead niobate and cadmium niobate; metal tantalates such as lithium tantalate, sodium tantalate, potassium tantalate, rubidium tantalate and lead tantalate; metal oxides such as titanium oxide, molybdenum oxide and tungsten oxide; and complex oxides such as lead titanate zirconate. Such a powder may be those having various shapes such as granular material, fibrous material and squamous material. Among them, fibrous powder and squamous powder are preferable because these can contribute also to the improvement in strength. Those having a dielectric constant of 100 or more determined at 25° C. and 1 MHz are particularly preferable. These may be employed either alone in a single sort or in combination of two or more sorts. Preferred specific examples of them include metal titanates represented by a general formula MO TiO
2
(in the formula, M denotes one kind or at least two kinds of metal selected from Ba, Sr, Ca, Mg, Co, Pd, Be and Cd) such as barium titanate, strontium titanate, calcium titanate, magnesium titanate, ba
Kawakami Shogo
Monde Hiroyuki
Tabuchi Akira
Lee Jinhee J
Otsuka Chemical Co. Ltd.
Reichard Dean A.
Townsend & Banta
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