Epistar Corp. v. International Trade Commission

566 F.3d 1321, 91 U.S.P.Q. 2d (BNA) 1180, 2009 U.S. App. LEXIS 10881, 2009 WL 1424448
CourtCourt of Appeals for the Federal Circuit
DecidedMay 22, 2009
Docket2007-1457
StatusPublished
Cited by53 cases

This text of 566 F.3d 1321 (Epistar Corp. v. International Trade Commission) is published on Counsel Stack Legal Research, covering Court of Appeals for the Federal Circuit primary law. Counsel Stack provides free access to over 12 million legal documents including statutes, case law, regulations, and constitutions.

Bluebook
Epistar Corp. v. International Trade Commission, 566 F.3d 1321, 91 U.S.P.Q. 2d (BNA) 1180, 2009 U.S. App. LEXIS 10881, 2009 WL 1424448 (Fed. Cir. 2009).

Opinion

RADER, Circuit Judge.

The United States International Trade Commission (“ITC” or “Commission”) found that Epistar Corporation (“Epistar”) infringed U.S. Patent No. 5,008,718 (“the '718 patent”). In reaching this determination, the Commission estopped Epistar from challenging the validity of the '718 patent. The Commission also construed the claim terms “transparent window lay *1324 er” and “substrate” of claims 1 and 6. After finding infringement, the Commission issued a limited exclusion order (“LEO”) prohibiting the importation of Epistar’s downstream light emitting diode (“LED”) products, regardless of the manufacturer or importer of these products. Because the Commission erred in estopping Epistar from arguing invalidity of the '718 patent when asserted against its products, but correctly construed the claim terms, this court affirms-in-part, reverses-in-part, and remands to the ITC with instructions to permit reconsideration of validity arguments. This court also vacates the LEO and remands to the Commission for reconsideration.

I.

Intervenor Philips Lumileds Lighting Company (“Lumileds”) owns the '718 patent, titled “Light-Emitting Diode with an Electrically Conductive Window.” The patent claims an LED with a special electrically conductive, transparent window layer on top of active LED layers of the semiconductor device. '718 patent col.5 1.32-col.6 1.45. The transparent window layer enhances current spreading with less light absorption, thereby providing a brighter light output and improved efficiency. '718 patent at col.2 11.4-8. The invention includes a semiconductor substrate, an electrical contact to the substrate, active layers of AlGalnP overlying the substrate, a transparent window layer of semiconductor different from AlGalnP overlying the active layers, and an electrical contact on top of the window layer. Id., col.2 1.48-col.3 1.5. The transparent window layer has a higher electrical conductivity and lower resistivity than AlGalnP. Id., col.2 11.11-18, 57-59; col.3 11.6-10.

Prior art surface — emitting LEDs, as depicted by figure 1 of the '718 patent shown below, generally comprise an absorbing substrate 10 on which several epitaxial layers 11-13 are grown to form the LED. These epitaxial layers may include an n-type confining layer 11 of AlGalnP grown on top of the substrate 10, followed by an active layer 12 of the same material, and a p-type confining layer 13 of the same material topping the active layer. This technological field refers to the combination of the p-type confining layer 13, active layer 12, and n-type confining layer 11 as the “p-n junction.” The LED generally provides a front, opaque electrical contact 14 on the front or emitting face of the LED, and a back electrical contact 15 on the substrate. Id., fig. 1; col.1 11.17-32.

*1325 [[Image here]]

For efficient operation, this type of LED injects current from the front metal contact and spreads it out laterally to the edges of the LED chip to generate uniform light across the “p-n junction.” However, when the sheet resistance of the upper p-type confining layer is not low enough, the current will not spread. Instead, the current will tend to flow directly down beneath the front contact toward the back contact. This defect results in most of the light being generated under the opaque front contact, referred to as “current crowding.” When current crowding occurs, “much of the light generated in this region is blocked and absorbed within the LED chip, thereby severely limiting the efficiency of the device.” '718 patent col.l 11.33-46.

According to the '718 patent specification, the prior art did not effectively solve this current crowding problem because the metal patterns that spread the current continued to block light emission. Transparent front contacts comprised of indium-tin oxide (“ITO”) were also unsatisfactory because they did not adequately spread the current. Id., col.l 1.57-col.21.3.

To solve these prior art difficulties of current crowding and high resistivity, the claimed invention teaches a transparent window layer with a higher electrical conductivity, and lower resistivity, than AlGalnP. This transparent window layer overlays the active AIGalnP LED layers and distributes current from the front contact to the active layers. The invention thus generates more uniform emission of light throughout the p-n junction and improves the efficiency of the device. Id., col.211.4-30.

*1326 The specification describes and illustrates two exemplary embodiments of an LED, constructed according to the principles of the claimed invention. Id., col.2 11.48-50, 60; col.4 11.36-56. Particularly, as shown in figure 2 below, the specification describes an LED “having active p-n junction layers [21-23] of AlGalnP overlain by a transparent window layer [24] of semiconductor different from AlGalnP, with a low resistivity and a bandgap greater than the active layers, so that the overlying layer is transparent to light emitted by the p-n junction.” Id., col.2 11.11-19. The specification describes this first embodiment as “[a]n exemplary light emitting diode (LED) constructed according to principles of this invention [that has] an n-type substrate” 20 with overlying active layers 21-23 and a transparent window layer 24 overlying the active layers. Id., col.2 1.48-col.3 1.5.

[[Image here]]

The alternative embodiment in figure 3 below fabricates an LED by “epitaxially growing active AlGalnP layers [32-34] on a GaAs temporary substrate [31], epitaxially growing on the active layers a layer of semiconductor [35] having a crystal mismatch with GaAs and a bandgap greater than the bandgap of the active layers, and selectively removing the GaAs temporary substrate.” Id., eol.2 11.21-26. The specification states, “this leaves a layer of transparent semiconductor [35] adjacent to the *1327 active layers [32-34] which has sufficient thickness to provide the strength of a substrate.” Id., col.2 11.26-30.

*1328 A.

Epistar merged with United Epitaxy Company (“UEC”) sometime before this litigation. Before that merger, both companies had a history of litigation with Lumileds over the '718 patent. In 1999, Lumileds brought suit against UEC in the Northern District of California, alleging that UEC’s products infringed the '718 patent. See United Epitaxy Co. v. Hewlett-Packard Co., No. C-00-2518-CW (N.D.Cal. Sept. 7, 1999). In response, UEC challenged the patent’s validity. In June 2001, District Judge Claudia Wilken granted Lumileds’ motion for summary judgment that the '718 patent claims were not indefinite, anticipated, or unenforceable due to inequitable conduct. Id., No. C-00-2518-CW, slip op. at 18-19, 23-24. The district court further denied UEC’s cross-motion for summary determination of non-infringement, indefiniteness, obviousness invalidity, and misjoinder of an inventor. Id., No. C-00-2518-CW, slip op. at 6-23, 25.

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566 F.3d 1321, 91 U.S.P.Q. 2d (BNA) 1180, 2009 U.S. App. LEXIS 10881, 2009 WL 1424448, Counsel Stack Legal Research, https://law.counselstack.com/opinion/epistar-corp-v-international-trade-commission-cafc-2009.