Motorola Inc. v. InterDigital Technology Corporation

Motorola, Inc. v. InterDigital Technology Corporation

Citation: 121 F.3d 1461 (Fed. Cir. 1997).


The patents involved in this case include:
1) 4,675,863 (the ‘863 patent)
2) 4,817,089 (the ‘089 patent)
3) 4,921,705 (the ‘705 patent)
4) 5,121,391 (the ‘391 patent)
5) 5,022,024 (the ‘024 patent)
6) 5,119,375 (the ‘375 patent)

The patents derive from a single parent application, filed on March 20, 1985 and describe digital wireless technology that utilizes a base station and subscriber stations, which tie into the land-tied public telephone network. The patents describe time division multiple access (TDMA), which is a method for sharing a single radio frequency between the base and subscriber stations. TDMA conserves available radio frequencies for digital data communication.

Issue: Whether ITC’s patents are valid and infringed and whether the jury correctly cited previous art work for the obviousness claims


The controversy between Motorola, Inc. (“Motorola”) and InterDigital Technology Corporation (“ITC”) began when Motorola sued ITC for a declaration of non-infringement and invalidity of the six ITC patents listed above on October 8, 1993. ITC countersued Motorola for infringement on the same six patents. ITC dropped the infringement claims for the ‘391 patent and the ‘024 patent before the trial began. ITC pursued twenty-four claims from the remaining four patents.

ITC argued Motorola infringed by contributory action and by inducement through Motorola’s participation in the manufacture, use or sale of four cellular phone systems: United States Digital Cellular (USDC), Japanese Digital Cellular (JDC), Groupe Special Mobile (GSM), and Mobile Integrated Radio System (MIRS).

District Court’s Findings:

The jury returned an unanimous verdict in favor of Motorola and found all of ITC’s claims not infringed and invalid. ITC filed a motion for judgment as a matter of law (JMOL) that the jury’s determinations were unsupported by substantial evidence. ITC alternatively asked for a new trial, and Motorola filed a motion for an award of attorney’s fees. The district court denied ITC’s and Motorola’s motions except it granted ITC’s motion for JMOL on the validity of claims 8, 9, and 11 of the ‘089 patent.

Appellate Court’s Analysis & Conclusion:

On appeal, Motorola contested (1) the district court’s grant of JMOL of non-obviousness of claims 8, 9, and 11 of the ‘089 patent, and (2) the district court’s denial of an award for attorney’s fees. In response, ITC filed a cross-appeal contesting (1) the district court’s refusal to grant a new trial, and (2) the district court’s denial of JMOL on the validity of the remaining twenty-one patent claims. ITC did not appeal the judgment of no infringement.

For claims 8, 9, and 11 of the ‘089 patent, the district court asked the jury to indicate the “specific prior art which renders such claim obvious.” The jury listed four prior art references, and Motorola conceded that these references alone were legally insufficient to prove the claims obvious because it lacked any teaching concerning modulation techniques. However, there was an art reference, Kinoshita (1979), which could have supported the obviousness claim if the jury had listed it. Because the jury did not list the Kinoshita (1979) art work, the district court correctly granted ITC’s motion of JMOL on claims 8,9, and 11 of the ‘089 patent.

The appellate court affirmed the district court’s grant of JMOL that Motorola failed to prove invalid claims 8, 9, and 11 of the ‘089 patent. The appellate court also affirmed the district court’s denial of attorney’s fees for Motorola. Additionally, the appellate court affirmed the district court’s denial of ITC’s motion for a new trial because testimony was sufficient to reconcile the jury’s inconsistent findings.

On appeal, ITC argued three general challenges to the jury’s findings of obviousness on the remaining twenty-one patent claims: (1) The Kinoshita (1981 Japan) prior art reference, on which the jury relied for each of its obviousness verdicts, is not enabling; (2) the district court improperly ignored evidence of secondary considerations in each of its obviousness determinations; and (3) no substantial evidence supports the jury’s implicit finding of a suggestion to combine prior art references for the various obviousness verdicts. Unfortunately, ITC did not raise the Kinoshita (1981 Japan) art reference enabling argument until appeal; therefore, appellate review is limited. The appellate court rejected all of ITC’s arguments and found the jury’s obviousness findings generally acceptable.

The appellate court reversed the district court’s denial of JMOL on the validity of claim 1 of the ‘705 patent and claim 178 of the ‘375 patent in favor of ITC. Claim 1 of the ‘705 patent is valid because the jury referred to the Kinoshita (1981 Japan) art work, which does not describe synchronization. Claim 178 of the ‘375 patent is valid because the jury failed to reference art work that described the half-duplex operation. The appellate court affirmed all of the remaining district court findings.

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