A 10-year-old lawsuit over a CCD manufacturing patent will go back before a judge after a federal appeals court said that the lower court had erred in ruling the patent invalid.The US Court of Appeals for the Federal Circuit said Loral Fairchild Corp. raised valid issues about whether it was using the technology in US Patent No. 3,931,674 before the publication of an article that Sony Corp., Toshiba Corp. and NEC Corp. used to weaken the patent case.In 1991, Loral sued about two dozen companies, alleging that they were infringing its patent, which covers manufacturing CCDs by applying layers of insulation material, gate electrodes and barriers on a semiconductor substrate.Patent in questionIn 1996, a jury found that the patent was valid and that Sony had infringed it. A district court judge, however, decided that "no reasonable jury" could have made that decision. Among the judge's reasons: Sony's manufacturing process was slightly different (in the order that the various layers were deposited) from the process that the Loral patent described. A December 1973 journal article by Darrel Erb preceded Loral's February 1974 patent filing.The appeals court affirmed the judge's ruling without addressing whether the Erb article was prior art that could invalidate the Loral patent.In response, Loral dropped its complaints against the remaining companies, except Toshiba and NEC, which it believed were more precisely following the patented CCD "recipe."In April 2000, Toshiba and NEC asked the court to make the same judgment in their cases as it had made in the Sony case. A district judge did so, saying that the Erb article was clearly prior art.Loral appealed the judgments, claiming that the inventor named in the patent, Gilbert Amelio, conceived the invention and used it in practice before the Erb article was published.The appeals court said Loral's argument raises a genuine issue of fact and sent the case back to the lower court for further proceedings.