Interdigital Technology Corporation & Ors v Lenovo Group Limited & Ors

In a computer-implemented means-plus-function patent claim, means for performing a function may require apparatus adapted or programmed to perform it, but continuous operation is not required. A claim requiring data to be limited to the next smaller permitted format requires that format to be identified and used as the limitation. It is insufficient that the data happens to fit within it as an incidental result of another process. For novelty, anticipation requires disclosure of the claimed selection-and-limitation scheme, not merely the same end result in particular circumstances. Claim construction is assessed by the claim language, the specification and the inventor’s purpose. A construction which causes a claim to cover prior art acknowledged in the specification should be approached with caution.

InterDigital appealed from Mellor J’s decision in the Patents Court, reported at [2022] EWHC 10 (Pat), revoking a European patent concerning multiplexing and transport-format selection in enhanced uplink telecommunications. The judge held that the patent would be essential to the relevant standard and infringed if valid, but lacked novelty over Filiatrault, including on the basis of an illustrative document called DXX/14. The appeal concerned the construction of the claim requirement to limit multiplexed data to the largest E-TFC smaller than the data allowed by the grants, and whether DXX/14 established anticipation. Lenovo also challenged essentiality and infringement through a respondents’ notice.

Arnold LJ gave the leading judgment, with Asplin and Lewison LJJ agreeing. The appeal was allowed.

1. Construction. In a computer-implemented means-plus-function feature, means for performing the stated function meant means adapted or programmed to perform it. The apparatus claims and equivalent method claims did not require the claimed means or method to operate continuously. They could apply in some transmission intervals and not others. Lenovo’s contrary construction was rejected.
2. The relevant claim integers required the next smaller E-TFC to be identified, selected or chosen and then used as the multiplexing limit. It was not enough that, after a different process using the grants as the limit, the data happened to fit within that E-TFC. The conclusion followed from the claim language, the specification’s description of the inventive scheme and the purpose of avoiding excess padding.
3. The Court accepted that the construction advanced on appeal was not procedurally barred. Claim construction was an issue of law, and a party could advance a different construction on appeal unless doing so caused procedural unfairness or prejudice. The adopted construction did not alter the judge’s conclusions on essentiality and infringement.
4. Novelty. Filiatrault did not disclose the additional selection step required by the claims. DXX/14 showed only that particular MAC-d PDU sizes and grants could produce the claimed result. It did not show that the next smaller E-TFC was selected and used as the multiplexing limit. The judge had therefore treated an incidental result as disclosure of the claimed method and had failed to perform the corresponding cross-check by reference to the method claim.
5. The Court regarded the late emergence of DXX/14 and the reasoning in Hickman v Andrews [1983] RPC 147 as supporting caution against constructing anticipation by ex post facto synthesis. It also applied the principle in Virgin Airways Ltd v Premium Aircraft Interiors UK Ltd [2009] EWCA Civ 1062; [2010] RPC 8 that claim construction should lean against covering prior art acknowledged in the specification. The High Court’s anticipation finding was consequently overturned.

• Court of Appeal (Civil Division): Arnold LJ, with Asplin and Lewison LJJ agreeing, allowed the appeal against the Patents Court’s anticipation finding: [2023] EWCA Civ 105.
• High Court of Justice, Patents Court: Mellor J ordered revocation of European Patent (UK) No. 3 355 537 on 29 April 2022 for the reasons in his judgment dated 6 January 2022: [2022] EWHC 10 (Pat).