Sued for patent infringement by a leading Chinese research institute, the client retained Kangrui to handle infringement defense and pursue full invalidation. Multi-channel, back-to-back prior-art searches, a Patent Reexamination Board oral hearing, and first-instance administrative litigation at the Beijing IP Court — all claims of the asserted patent invalidated.
The client is a U.S. LED semiconductor leader, sued for invention-patent infringement by a top Chinese research institute. After preliminary risk assessment, the client retained Kangrui to handle infringement defense in parallel with full-scope invalidation of the asserted patent.
Between the product's technical solution and the patent's claim scope, we needed to identify the claims that posed actual infringement risk and concentrate prior-art searches on them.
Interpretations the patentee makes during invalidation can be used in the follow-on infringement litigation under prosecution history estoppel.
For the must-invalidate claims, we ran a multi-channel, simultaneous back-to-back search strategy, ultimately locating reference documents that strongly affected inventive step.
At the Patent Reexamination Board oral hearing, we argued that the distinguishing features between the asserted claims and the cited references constituted general knowledge in the field, and forcefully rebutted the opposing counsel's point-by-point counter-arguments — steering the patentee into narrowing interpretations on certain key features.
Invalidation: The Patent Reexamination Board accepted all of our invalidation grounds and invalidated the asserted patent in full.
Administrative litigation: The opposing side challenged the invalidation decision before the Beijing IP Court; after hearing, the court held the facts and reasoning supporting the invalidation decision sufficient and affirmed the decision. No further appeal was taken and the ruling became final.
Related effect: With the asserted patent fully invalidated, the underlying infringement suit lost its basis automatically — the client was relieved of further infringement-litigation burden.
This is a textbook defensive invalidation in an infringement context. The search strategy and the oral-hearing cadence were both designed around the ultimate goal of the infringement litigation — even where full invalidation cannot be obtained, steering the patentee into narrowing interpretations of key features lays a beneficial estoppel foundation for the infringement defense.
For foreign-related enterprises, parallel "defense + counter-attack" capacity is standard in Chinese IP litigation. This case offers a reusable methodology.