If you’re unjustifiably threatened with patent infringement and cease activities as a result, you can in certain circumstances bring an action and recover damages.
That’s precisely what happened here.
Clariant Produkte (Deutschland) GbmH, a well known manufacturer of organic pigments wrote to Sudarshan Chemical Industries Ltd (another such manufacturer) about one of Sudarshan’s products, saying:
“Certainly you will not be interested in continuously effecting a patent infringement, which may involve the most serious penalties to the infringer and his customers”
The Court of Appeal, having found the relevant patent to be invalid, considered the letter to be a groundless threat to Sudarshan’s customers (even though it was only sent to Sudarshan).
It also found that Clariant could not rely on a defence that when it made the threat it did not know that the patent was invalid, by imputing onto Clariant knowledge of its patent attorney and inventor.
A reminder of the risks associated with alleging patent infringement.