The decision of the Delhi High Court in Trident Limited vs Controller of Patents [C.A.(COMM.IPD-PAT) 162/2022] addresses a recurring issue in Indian patent cases, as to how inventive step under Section 2(1)(ja) of the Patents Act, 1970 is to be assessed, particularly in cases where an invention emerges from a known technological field but claims a distinct technical outcome. The judgment examines whether an invention can be dismissed as obvious merely because it employs known processes or materials, or whether the technical effect and outcome achieved by the invention must be independently evaluated.
The judgment further examines how it is crucial to clearly establish obviousness when common general knowledge points away from the claimed invention. At the heart of the dispute were allegations of hindsight bias in patent examination and the failure of the Patent Office to demonstrate a clear and reasoned pathway from the prior art to the claimed invention, as the impugned order was silent on how the cited prior art provided any teaching that would lead to the blended yarn as claimed in the subject patent application.
Facts of the Case
The patent application No. 1867/DEL/2010 by Trident Limited titled “Air Rich Yarn and Fabric and its Method of Manufacturing” was refused by the respondent Controller on the ground of lack of inventive step in view of the cited prior art documents D1–D4, which disclosed yarns and fabrics made using blends of water-soluble and non-soluble fibres. Aggrieved by the rejection, the appellant filed an appeal before the Delhi High Court challenging the impugned order of refusal.
Arguments by the Appellant
The appellant submitted that the invention relates to yarns and fabrics possessing a homogeneous porous structure, achieved by blending base material fibres with water-soluble fibres in specific proportions and under defined processing conditions. Upon dissolution of the water-soluble fibres during fabric treatment, the resulting yarn exhibited pores homogeneously distributed across its radial cross-section.
The appellant contended that the claimed invention was not merely the use of water-soluble fibres in yarns, which is a concept admittedly known in the art, but the achievement of a homogeneous distribution of pores across the radial cross-section of the yarn. According to the appellant, this structural characteristic resulted in superior absorbency, faster drying, and increased thickness of the fabric, making it particularly suitable for terry towels and similar applications.
It was argued that none of the cited prior art documents disclosed or even suggested homogeneous radial distribution of pores, which constituted the defining feature of the invention. The appellant contended that process similarity does not necessarily imply product identity, particularly where the invention claims a specific structural outcome. According to the appellant, conventional techniques resulted in PVA fibres migrating towards the yarn core, leading to hollow or blind pores. In contrast, the claimed invention produced through-pores uniformly distributed throughout the yarn structure, a technical outcome not disclosed in the prior art.
The appellant further submitted that the claims specifically recited homogeneous distribution of pores formed between the base material slivers, and not homogeneous distribution of fibres. The respondent’s finding that “a homogeneous distribution of fibres along the radial cross-section of the yarn is the ultimate goal for any blending of fibres” was therefore characterised as misleading and based on an incorrect test. It was contended that none of documents D1 to D4 taught or contemplated homogeneous distribution of pores or water-soluble fibres across the radial cross-section of a yarn.
Reliance was placed on Enercon (India) Limited vs Aloys Wobben, 2013 SCC OnLine IPAB 91; Pharmacyclics, LLC vs Controller General of Patents, Designs, Trademarks and Geographical Indications, 2020 SCC OnLine IPAB 37; and Avery Dennison Corporation vs Controller of Patents and Designs, 2022 SCC OnLine Del 3659, to submit that even after a hindsight analysis, where a combination of prior art documents fails to provide the result claimed in the invention, such prior art must be considered as teaching away.
Finally, the appellant submitted that the Controller had relied on overlapping ranges of fibre composition without explaining why a PSITA would be motivated to select the specific range claimed. They also highlighted detailed examples and process parameters disclosed in the specification, demonstrating deliberate technical measures taken to achieve the claimed outcome, none of which were addressed in the impugned order.
Response of the Respondent Controller
The respondent Controller defended the refusal of the patent application by contending that homogeneous blending of fibres is a routine objective in spinning technology and that the claimed outcome was an expected result of known processes. It was submitted that the application lacked experimental validation demonstrating homogeneous pore distribution and that the claims were based on qualitative assertions rather than a demonstrable technical advancement.
The respondent further argued that the standards for assessing inventive step under Indian patent law differ from those applied in jurisdictions such as the United States and Europe, and cautioned against importing foreign doctrines into the Indian framework. It was maintained that the cited prior art documents, when read together, provided sufficient motivation for a person skilled in the art to arrive at the claimed invention.
Analysis and Findings of the Court
The Delhi High Court undertook a detailed analysis of the claims, the specification, and the cited prior art. It was observed that the Controller had failed to identify any specific disclosures in prior art documents D1 to D4 that taught or suggested homogeneous pore distribution across the radial cross-section of a yarn. The Court noted that merely stating that uniform blending is a general objective in spinning technology does not establish obviousness of the claimed structural outcome.
The Court observed that, in light of the publications placed on record by the appellant, it became crucial to clearly establish obviousness, particularly where common technical knowledge taught away from the claimed invention. The Court found that the impugned order was silent on how the cited references D1 to D4 provided any teaching that would lead a skilled person to select water-soluble fibres in the range of 8% to 25% of the total weight of the blended yarn, as claimed under Claims 1 and 8 of the subject application.
The Court held that the Controller’s reasoning was internally inconsistent. While the impugned order acknowledged homogeneous distribution of water-soluble fibres, it simultaneously concluded that no special measures had been adopted to achieve such distribution. This contradiction, coupled with the failure to analyse the examples and process parameters disclosed in the specification, rendered the refusal order unsustainable.
Relying on precedents such as Enercon, Pharmacyclics, and Avery Dennison, the Court ruled that hindsight-driven reconstruction of an invention using prior art is impermissible. The Court observed that inventive step analysis must focus on what the invention achieves, not merely how it is made. Even if individual process steps are known, a novel and non-obvious technical result can confer inventiveness. The Court accepted the appellant’s argument that common technical knowledge in fact taught away from homogeneous pore distribution due to natural fibre migration tendencies.
Decision of the Court
The Delhi High Court set aside the impugned order and remanded the matter to the Patent Office for fresh consideration. It directed that the application be re-examined by a different Controller, with due consideration of the specification, examples, and auxiliary claims submitted by the appellant. The Court emphasised that the assessment must be conducted uninfluenced by earlier observations and strictly in accordance with the law.
Conclusion
This judgment sets new paradigms for inventive step analysis by the Controller. Where a combination of two prior art documents fails to provide the result claimed in an invention, such prior art must be considered as teaching away. The Controller must clearly demonstrate that the cited prior art provides any teaching that would lead a skilled person to the claimed invention. It must also explain how a person skilled in the art (PSITA) could arrive at the invention without prior knowledge of the invention itself.
Authors: Manisha Singh and Shivi Gupta
First Published by: Mondaq here