SINGAPORE - A company which makes synthetic diamonds in Singapore has won a patent case against a member of the international De Beers Group, ending a seven-year court battle over the methods used in growing the gemstones.

Britain-based Element Six Technologies had sued Singapore firm IIa Technologies in 2016, alleging that the latter had infringed two of its patents registered in Singapore.

IIa (pronounced 2A) denied infringing the patents. The company also disputed the validity of the patents and sought to revoke them in a counterclaim.

One patent was revoked by the High Court in 2020.

Last Friday, in a landmark decision which addressed novel points of patent law, the Court of Appeal ordered the second patent to be revoked as it was not sufficiently clear and complete.

The revocation of the patents means that Element Six, which describes itself as a global leader in the design, development and production of “synthetic diamond supermaterials”, cannot stop others from using the process.

The legal proceedings come at a time when there is growing interest in lab-grown diamonds.

The Straits Times reported earlier in February that a report by Allied Market Research projected that the global market for lab-grown diamonds will reach US$49.9 billion (S$66.8 billion) by 2030.

Element Six is part of the De Beers Group, one of the largest diamond producers in the world, which, in turn, is a subsidiary of global mining company Anglo American.

The court case centres on the production of synthetic diamonds using a process known as chemical vapour deposition.

The process involves placing a substrate, which is also known as a diamond seed, in a reactor containing a mixture of gases including methane and hydrogen.

Upon exposure to high energy, the gaseous molecules break up into plasma containing carbon atoms. The carbon atoms are then deposited on the substrate, growing the synthetic diamond layer by layer.

Element Six alleged that IIa had produced diamonds using the method in its patents.

One patent, identified as SG 508, relates to a method of changing the colour of a lab-grown diamond by heat treatment.

The other, SG 872, relates to a method of growing a new type of diamond with certain properties.

In February 2020, after a six-week trial, the High Court ruled that SG 508 was invalid, but that SG 872 was valid and had been infringed by IIa.

IIa – represented by Mr Tony Yeo, Ms Meryl Koh and Mr Javier Yeo from Drew & Napier – and Senior Counsel Davinder Singh from Davinder Singh Chambers, then appealed.

In a rare move underscoring the complexity of the case, the appeal judges asked parties to prepare a “primer” document and conduct a technical tutorial to help them in “coming to grips with the difficult material”.

Last Friday, the court, comprising Chief Justice Sundaresh Menon and Justices Judith Prakash and Steven Chong, issued a 126-page judgment, ordering SG 872 to be revoked.

Under the Patents Act, a patent is valid only if it discloses the invention “in a manner which is clear and complete”.

The court found that the patent was not sufficiently clear, as it did not set out the method to allow a skilled person reading the patent to grow the lab-grown diamond.

The court found that the patent was also insufficient because it was “uncertain” – even if a skilled person grew a diamond, he would not know whether that diamond infringed Element Six’s patent.