THE ROLE OF EXPERIMENTAL DATA AND
PRIOR ART COMBINATION IN PATENT OBVIOUSNESS

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KEY FACTS OF PRESENT CASE:

The Appellant, Saint Gobain Glass France's patent application as a national phase entry under the Patent Cooperation Treaty, claiming priority from a 2015 French filing, was rejected by the Controller of Patents after a pre-grant opposition by Asahi India Glass.

CASE SET UP BY APPELLANT:

The appellant appealed the refusal of their patent application for a material comprising a stack of thin layers on glass designed to achieve specific optical properties, such as high external reflection, neutral transmission colors, and solar control. The appellant argued that the Controller of Patents improperly applied the inventive step test by combining prior art documents in hindsight, and contended their invention demonstrated a technical advancement through optimized layer thickness and configuration, supported by experimental data and expert affidavits. The appellant amended their claims to distinguish the invention from prior art, asserting it was not an obvious improvement but a genuine inventive step deserving patent protection.

CASE SETUP BY THE RESPONDENTS:

The respondents, including the Assistant Controller of Patents and Asahi India Glass, argued that Saint Gobain's patent application lacked an inventive step under the Patents Act, 1970. The assessment was based on the 5-step inventive step analysis method laid out in the landmark case F. Hoffmann-La Roche Ltd. v. Cipla Ltd. (2008) by the Delhi High Court. They maintained that the invention merely involved routine optimization of known parameters and the optical improvements were considered predictable to a person skilled in the art. The Controller found the comparative experimental data insufficient and inconsistent with the amended claims and relied on the pre-grant opposition by Asahi to support the refusal. The respondents also emphasized that the French patent grant had no bearing on Indian patentability, given the territorial nature of patent law.

OBSERVATION OF THE BENCH

The bench found that the claimed technical improvements, such as changes in layer thickness and material combinations, were routine optimizations that a person skilled in the art would predictably make rather than a true inventive advancement. The court upheld the Controller’s refusal, stating that the comparative experimental data provided was insufficient and incomplete to establish any significant or surprising improvement over prior art. It confirmed that combining prior art references to assess obviousness is a legitimate approach and rejected the appellant’s objection based on hindsight. The decision reinforced the high threshold for inventive step in India and clarified that foreign patent grants do not impact Indian patentability assessments.

KEY TAKEAWAYS

The court reaffirmed that patents in India require a genuine inventive step beyond routine optimization. Combining related prior art references to assess obviousness is valid and not hindsight. Comparative experimental data must be complete, consistent, and directly support the invention, as incomplete data weakens the claim. Patent decisions in one country do not affect patentability in another, reflecting the territorial nature of patents. Overall, the judgment underscores the high standard of clear technical advancement and non-obviousness needed for patent approval, especially in technology optimization cases.