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Murata Manufacturing Co., Ltd. v. Bel Fuse

March 12, 2008


The opinion of the court was delivered by: Joan B. Gottschall United States District Judge

Judge Joan B. Gottschall

Magistrate Judge Jeffrey Cole


Defendants Bel Fuse, Inc. et al. (collectively "Bel") have filed a motion seeking summary judgment of invalidity against plaintiff Murata Manufacturing Co., Ltd.'s ("Murata") U.S. Patent No. 5,069,641 ("the '641 patent-in-suit") based on grounds of obviousness. Murata has cross-moved for summary judgment of nonobviousness of the '641 patent-in-suit. For the reasons set forth below, both Bel's motion and Murata's cross-motion for summary judgment are denied.


Jacks and plugs are the familiar connectors by which telephones, computers and other such information processing and transfer devices are connected with wires or cables in order to receive and transmit information from and to external sources. A constant problem for such connectors, however, is electromagnetic interference ("EMI") generated by electrical sources both intrinsic and extrinsic to the device in question. Such EMI can degrade and interfere with the electrical signals passing into and out of the machine via the connectors. To address this problem, filters, or "noise suppression" devices have been devised that "screen out" the undesirable EMI and improve the signal-to-noise ratio of information passing through the connectors.

Traditionally, such filters have been mounted on the device's circuit board as part of the rest of the device's circuitry. Unfortunately, these filters occupy space on the circuit board, and as the exponential trend towards miniaturization of electrical devices has proceeded apace, internal space for components has come at an ever increasing premium. One solution to this problem has been to integrate the noise filter directly into the connector itself, and it is this approach that brings the court to the subject matter of the instant case.

Murata's '641 patent-in-suit discloses "a compact and economical modular jack*fn1 which also functions as a noise suppressor." '641 patent-in-suit. The modular jack "has a printed board containing a noise suppressing electronic element in an insulating housing." Id. "A contactor for contacting with a plug and a terminal for connecting with a circuit board are electrically connected with the electronic element by wires on the printed board." Id. Thus, "it is possible to obtain a compact modular jack containing a noise suppressing electronic element, which modular jack hardly receives external noise." Id. The '641 patent-in-suit issued on December 3, 1991; the inventors of record are listed as Yukio Sakamato, Toshio Hori, and Iwao Fukutani, and the sole assignee of the patent is Murata.

The prior art, as disclosed in the '641 patent-in-suit, consisted of U.S. Patent No. 5,015,204 (and German Patent No. DE-AS-202342) (the "'204 patent"), which also disclosed a modular jack with a noise suppressing element. However, the '204 patent, which was patented by the same inventors and also assigned to Murata, disclosed a different type of noise suppressing element. The noise suppressing element of the '204 patent comprised a "common mode choke coil" which consists of a "ring shaped core and two coils coiled thereon" rather than having the noise suppressing elements mounted on a circuit board within the jack. '204 patent. The pairs of coils are wrapped in opposite turnings around the ring-shaped core, so any common mode interference (externally generated noise that is present in both coiled wires) induces opposing electromagnetic fields which subtract from, and thus cancel, each other (this is known as common mode rejection).

Importantly, one end of the coil wire is made to be a contactor in the jack for a plug from a cable or wire, and the other end is used as a terminal for connecting the jack to the rest of the circuit board. Id. Thus, electrical current entering from the plug flows continuously through the wire, which is coiled around the ring-shaped core, and directly to the internal circuitry of the device, without any intervening elements (unlike the '641 patent-in-suit, which teaches wires connecting to and from the integral circuit board, as well as wires on the board contacting the noise suppressing elements).

Not disclosed in the '641 patent-in-suit, but cited by Bel in its motion for summary judgment, is another U.S. Patent, No. 4,789,847 (the "'847 patent"), also issued to Messrs. Sakamato, Hori, and Fukutani, and assigned to Murata. The '847 patent discloses a "filter connector," rather than the modular jack disclosed in both the '204 and '641 patents. Both parties have acknowledged that the filter connector disclosed in the '847 patent is of a type generally known as a D-subminiature connector ("D-sub connector"). Sub-D connectors are familiar to anyone who has examined the back of a computer; the plug and jack are typically roughly "D-shaped" when viewed from the connector surface. The '847 patent discloses a female type filter connector with an integral noise suppression element on a "printed circuit board" upon which are mounted the "filter elements." '847 patent. The circuit board is connected to a first terminal pin that connects to the pin of the incoming wire, and also to a second terminal pin, which in turn connects to the circuitry of the device in which the connector is mounted. Id.

Thus, there are three principal patents that concern the court in this case: (1) the '204 patent, which teaches a modular jack with an integral noise suppression element consisting of an uninterrupted wire connecting the jack's input and output (the common mode choke coil); (2) the '847 patent, which teaches a D-sub connector with an integral noise suppression element mounted on a circuit board and connected by conducting pins to the connector's inputs and outputs; and (3) '641 patent-in-suit, the patent at issue in this case, which teaches a modular jack with an integral noise suppression (as in the '204 patent); which element is mounted on a circuit board and connected to the inputs and outputs of the jack via conducting elements, as well as at least one wire on the circuit board (as in the '847 patent).

In 1999, Stewart Connector Systems, Inc. ("Stewart") (Bel's predecessor in interest) became aware of Murata's '641 patent-in-suit. Bel's Mot. for Summ. Judg. 2. Stewart had been developing its own modular jack with an integral noise suppression element (known as the MagJack(r)) and on August 20, 1999 Stewart contacted Murata by letter initiating negotiations for a licensing agreement. Id.

Negotiations had almost borne fruit, when, Bel alleges, Stewart initiated its own study of the validity of the '641 patent-in-suit, and discovered the '847 patent, which was not disclosed in the '641 patent-in-suit. Id. On January 29, 2001, Stewart's counsel furnished Stewart with a detailed opinion letter stating, inter alia, that Murata's '641 patent-in-suit would likely be found invalid as obvious in view of the two prior art references owned by Murata (the '847 and '204 patents), all ...

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