## Facts

- British Telecommunications PLC (BT) owned U.S. Patent No. 4,873,662 (the Sargent patent) claiming a “digital information storage, retrieval and display system.”
- The asserted claims required, among other elements, (1) a “central computer” and (2) “plural blocks of information,” each block having a contiguous display portion and a contiguous non-display portion containing “complete addresses” of other blocks.
- BT alleged Prodigy Communications Corp., an Internet service provider, infringed by providing Internet access that enabled subscribers to retrieve and display web pages and follow hyperlinks.
- In a prior claim-construction ruling, the court construed “central computer” as a single device in one location serving as the system hub to which all remote terminals connect, and construed “plural blocks of information” to require contiguous display and non-display portions stored together within each block.
- After claim construction, Prodigy moved for summary judgment of noninfringement.

## Issues

1. Whether Prodigy’s Internet services literally satisfied the asserted claims’ “central computer” and “plural blocks of information” limitations.
2. If not, whether Prodigy’s services infringed under the doctrine of equivalents.
3. Whether Prodigy could be liable for contributory infringement or inducement based on alleged subscriber infringement.

## Decision

- The court granted Prodigy’s motion for summary judgment of noninfringement.
- The court held there was no literal infringement because the accused Internet system lacked (1) a single, hub-like “central computer” and (2) the claimed contiguous “plural blocks of information” structure.
- The court held there was no infringement under the doctrine of equivalents because treating the distributed Internet and HTML structure as equivalents would vitiate key claim limitations and, as to certain scope, was limited by prosecution-history estoppel.
- The court held there was no contributory infringement or inducement because there was no underlying direct infringement by Prodigy or its subscribers.

## Legal Principles

- After claim construction, summary judgment of noninfringement is proper where no reasonable jury could find the accused system practices each claim limitation.
- A claim limitation requiring a “central computer” construed as a single device in one location is not met by a distributed network of many independent computers and servers.
- A claim requiring “blocks of information” with contiguous display and non-display portions is not met by HTML code in which displayable content and non-display elements (e.g., tags and link markup) are interleaved rather than separated into contiguous portions.
- The doctrine of equivalents cannot be used to eliminate or effectively read out an express claim limitation; substantial architectural differences defeat equivalence.
- Contributory infringement and inducement require an underlying act of direct infringement; absent direct infringement, secondary liability fails as a matter of law.

## Conclusion

The court entered summary judgment for Prodigy, concluding that neither Prodigy’s Internet services nor subscriber use of HTML hyperlinks met the patent’s construed “central computer” and “plural blocks of information” limitations, and that the doctrine of equivalents and secondary-liability theories could not supply infringement without direct infringement.


British Telecommunications PLC v. Prodigy Communications Corp., 217 F. Supp. 2d 399 (S.D.N.Y. 2002)