Insights into Chinese patent claim construction rules in draft judicial interpretation

As China’s scientific and technological innovation advances, patent infringement disputes have become increasingly diverse and complex, posing challenges to existing judicial rules. Against this backdrop, the Draft Judicial Interpretation (III) on Several Issues Concerning the Application of Law in the Trial of Patent Infringement Disputes (the Exposure Draft) released by the Supreme People’s Court (SPC) duly addresses new demands and issues arising in patent infringement judicial practice.

Consisting of 31 articles, the Exposure Draft covers jurisdiction, standing to sue, claim construction, infringement evaluation, non-infringement defences, bad-faith litigation, damages, and other matters, aiming to unify adjudication standards and respond to emerging needs in the judicial protection of patents amid technological innovation.

The claim construction rules established in articles 10 and 11 of the Exposure Draft underscore the judicial trend towards a more refined and rigorous determination of the scope of patent protection, while also raising professional standards for patent attorneys.

Patent attorneys are expected to not only fully command patent examination rules applicable to prosecution and invalidation proceedings but also gain an in-depth understanding of claim construction rules in infringement litigation. They must proactively identify potential risks, precisely delineate the technical boundaries of inventions to be protected at the drafting stage, and balance the breadth of protection and stability of claims when making amendments and arguments at later stages. This serves to prevent the subsequent narrowing of the patent scope caused by drafting oversights or improper procedural acts.

Focusing on the pivotal issue of claim construction, this article analyses articles 10 and 11 of the Exposure Draft with reference to landmark SPC judicial cases to provide insights for industry discussion.

Article 10 stipulates: “Where the accused technical solution has the prior art defect(s) intended to be overcome by the patent as recited in the Description, the courts shall determine that the technical solution does not fall within the scope of protection of the patent right.”

This provision establishes the prior art defect exclusion rule in claim construction, thereby incorporating the purpose of the patented invention as a factor in determining the scope of patent protection. It expressly excludes from the protection scope technical solutions that replicate the prior art defect the patent seeks to overcome, to ensure that the protection aligns with the patent’s actual technical contribution.

Two core conditions must be met for its application:

• The accused technical solution replicates the prior art defect recited in the Description; and

• The defect is precisely what the relevant patented technical solution aims to resolve to achieve its object.

In practice, careful determination is required as to whether the prior art defect is the one targeted and addressed by the patented solution.

Specifically, not all prior art defects recited in the Description should automatically be deemed the defect that the patented solution aims to resolve. In particular, where the Description mentions certain irrelevant prior art defects due to drafting oversights, or recites multiple prior art defects at different levels, and the patent encompasses multiple patented solutions, the correspondence between each patented solution and each prior art defect must be determined concretely by reference to the Description’s disclosure regarding the prior art defects, the patented solutions, and their improvements over the prior art.

The above judicial logic is reflected in earlier SPC precedents. For example, in Case (2021) SPC IP Civil Final No. 860, the court held that to overcome defects in the background art, the patent adopts the improved solution of “forming a stepped deformation at the edge of the first clamping member”. The court further held that the accused product still forms deformation at the edges of both clamps, which shows no substantive difference from the technical solution disclosed in the background part of the patent and exhibits the defect intended to be overcome by the patent.

The court therefore concluded that the accused technical feature does not constitute an equivalent of the corresponding feature of the patent.

Nevertheless, in the application of Article 10, certain issues require further clarification.

First, its coordination with the all elements rule – the fundamental principle for patent infringement determination – has yet to be clarified. If it permits the courts to deny infringement solely on the ground that the accused technical solution reproduces the prior art defect the patent intends to overcome, the all elements rule may be undermined.

Second, the identification of the defect intended to be overcome by the patent involves subjectivity, and may give rise to disputes where the Description lists multiple defects that may be overcome or fails to clearly specify the defect addressed by the patent.

Third, it remains unclear whether a finding that an accused technical solution “has the prior art defect” requires its corresponding technical means to be identical or substantially identical to that of the prior art. Focusing solely on defects rather than technical means may enable abuse of the rule to circumvent patent protection, thereby undermining patent rights.

Article 11 stipulates: “Where the accused infringer can prove that a restrictive amendment or statement made by the patent applicant or patentee to the Claims, Description, or Drawings during patent prosecution or invalidation proceedings was not expressly denied, the courts shall not allow the reintroduction of the abandoned parts into the scope of protection.”

This provision, together with Article 13 of the Judicial Interpretation (II) on Several Issues Concerning the Application of Law in the Trial of Patent Infringement Disputes (2016), refines the doctrine of prosecution history estoppel and forms a complete regulatory framework. Specifically, Article 13 of Judicial Interpretation (II) clarifies that restrictive amendments or statements expressly denied by the examination authority shall be exempt from estoppel, whereas the aforementioned Article 11 confirms that estoppel applies where such amendments or statements are not expressly denied.

Three key prerequisites govern the application of Article 11:

• The patentee has made a restrictive amendment or statement during patent prosecution or invalidation proceedings;

• The amendment or statement was not expressly denied by the examination authority, including where the examination authority tacitly accepted it, or granted the patent or maintained its validity based on such restriction; and

• The accused infringer has discharged its burden of proof with regard to the foregoing facts.

The core spirit of this provision has already been reflected in prior judicial practice, and several typical cases have further clarified the boundaries for the application of the rule.

In Case (2023) SPC IP Civil Final No. 1747, the court held that the patent in suit was immediately granted after the patent applicant made a restrictive statement, and the statement was not expressly denied by the examination authority. The court therefore concluded that the statement constituted surrender of the relevant technical solution and that the patentee’s attempt to include that solution within the scope of patent protection in infringement litigation was estopped.

In Case (2017) SPC Civil Review No. 1826, the court held that to determine whether a restrictive statement has been expressly denied, it is necessary to conduct an objective and comprehensive review of the examination history of the relevant technical feature during patent prosecution and invalidation proceedings, focusing on whether the statement was accepted by the examination authority and whether it contributed to the grant of the patent or the maintenance of its validity. The court further held that if a restrictive statement made during prosecution was expressly denied and that finding was not overturned in invalidation proceedings, the statement shall be deemed not to constitute surrender of the relevant technical solution – even if the examination authority offered no comment on it during invalidation – and estoppel shall not apply.

In Case (2011) SPC Civil Retrial No. 306, the court held that estoppel applies only to technical solutions as to which the patentee has made a voluntary surrender. The court further held that where an independent claim is declared invalid and the patent is maintained valid on the basis of a dependent claim, and the patentee has not voluntarily surrendered the relevant technical solution, the criteria for finding surrender of the technical solution shall be strictly applied. If the additional technical feature defined in the dependent claim is not encompassed by the independent claim, it shall not be presumed that all technical solutions other than the one incorporating the additional technical feature have been wholly surrendered.

Furthermore, in Case (2021) SPC IP Civil Final No. 836, the court also held that not all restrictive amendments or statements constitute surrender of a technical solution; only those made to overcome validity challenges during prosecution and invalidation proceedings – and that were not expressly denied – will give rise to estoppel.

This provision reinforces the principle of good faith in the patent system, holding patentees accountable for their acts in administrative proceedings. However, using only “not expressly denied” as the criterion for finding surrender of a technical solution may readily lead to the abuse of prosecution history estoppel in practice, prejudicing the patentee’s legitimate rights.

The primary purpose of prosecution history estoppel is to prevent the patentee from ‘having it both ways’ – obtaining a patent grant or maintaining its validity by surrendering technical solutions during prosecution or invalidation proceedings, then reincorporating those surrendered technical solutions into the scope of patent protection under the doctrine of equivalents in infringement litigation.

For estoppel to apply, the patentee’s restrictive amendments or statements must genuinely constitute surrender of the relevant technical solutions. Such a finding requires a comprehensive assessment of the specific contents of the restrictive amendments or statements and their actual impact on patent prosecution and invalidation proceedings.

To better align with the essence of estoppel, further revisions to Article 11 may be necessary. A requirement that the restrictive amendments or statements have materially contributed to the grant or maintenance of the patent may be added as a prerequisite for estoppel, alongside the requirement of not being expressly denied, to ensure that estoppel applies only where the patentee has surrendered the relevant technical solution through such amendments or statements and has actually derived a benefit therefrom.

Alternatively, exceptions may be introduced – such as technical solutions unforeseeable at the time of the restrictive amendments or statements – drawing on the judicial practice of other jurisdictions, to enhance the flexibility and reasonableness of applying prosecution history estoppel.

In summary, articles 10 and 11 of the Exposure Draft both set forth exclusion rules relating to the scope of patent protection. Article 10 takes the “prior art defect” recited in the Description as the basis for determination, focusing on the inherent technological advancement of the patent, whereas Article 11 takes the “restrictive amendments or statements” made during patent prosecution and invalidation proceedings as the basis for determination, focusing on the patentee’s procedural good-faith obligation.

The two provisions directly address long-standing controversies in judicial practice and further elaborate relevant adjudicative rules. Nevertheless, they require further refinement to effectively balance the interests of patentees and the public in application and to better suit the demands of patent judicial protection in an era of technological innovation.