A Patent right is a privilege granted by the State to the first inventor of any new manufacture or invention, that he and his licensees shall have the sole right, during the term of twenty years, from the date of filing the patent application, irrespective of whether it is filed with provisional or complete specification. In India, the The Patents Act, 1970 governs suits relating to patents.
The patentee must be the true and first inventor. If he has acquired the knowledge of the invention in a foreign country and introduces it into India still he will be looked upon as the first inventor.1)
An invention is different from a discovery, and a discovery is not subject-matter for a patent unless it is an addition not only to knowledge, but to known inventions, and produces either a new and useful thing or result, or a new and useful mode of producing an old thing or result.2)
Requisites of a good patent are:
A sufficient description of the nature of the invention and the mode of carrying it into effect, so as to enable ordinarily skilful persons to practise and use it at the end of the term for which the patent is granted must be filled with the proper authorities. If the specification is ambiguous, insufficient, or misleading, the patent will be void.6)
A patent privilege may be infringed in several ways:
A person who has in his possession, for the purpose of sale, an article which is an infringement of a patent thereby renders himself liable for infringement, however innocently he may have acquired the article; as, for instance, by an innocent purchase from an infringing manufacturer; and notwithstanding that he may not have actually exposed it for sale.7)
A patent is a privilege granted by the Crown, but as against subjects only, and not against the Crown; and hence the Crown may, by its officers, servants, or agents, use a patent process without compensating the patentee; but this does not extend to a, tradesman who contracts to do work for the Crown, and in doing it uses the patent process, he becomes liable to the patentee.8) To manufacture abroad according to a process patented in India, and then import the substance for sale in India, is a, violation of the patent.9) Also, importing of such an article, though not for sale yet for the purpose of experiment or instruction, is a user for advantage and an infringement.10) Any one who uses what is an infringement of a patent is liable, though he was only an agent or servant of another who is not himself sued. Thus, the captain of a vessel fitted with pumps which were an infringement of the plaintiff's patent, was held liable, although he was not owner of the vessel.11) Posting at a foreign post-office a parcel addressed a trader in London containing an article patented in England does not constitute an infringement of the patentee's rights on the part of the sender.12)
The plaintiff in a patent action is, strictly speaking, entitled to recover such an amount of damages as will fairly compensate him for the injury which he has sustained by reason of the wrongful acts of the defendant proved at the trial. The measure to be applied in assessing damages for infringement of a patent is the pecuniary loss actually sustained by the patentee through the infringement, and no more.13) In order to recover substantial damages in a patent action, it will be necessary for the plaintiff to give such evidence as will enable the Court to estimate the extent of the loss and injury which he has sustained; and in the absence of such evidence, the plaintiff is not entitled to more than nominal damages.14) The damages are to some extent matter of calculation by taking an account of the profits, which have arisen from the use of the invention, from the person who has pirated the same. Where a patentee has been in the habit of granting licenses at a certain royalty, the measure of damages will be the amount of royalty which ought to have been paid, but it will not include a manufacturing profit.15) A plaintiff cannot pray for an account of profits and for damages. He must elect between the two remedies.
When a patentee can show that he has possession of a patent privilege, under colour of a title, not evidenced merely by his patent, but also supported long and undisputed enjoyment, and can also show that the defendant against whom he is proceeding has violated the privilege, he shall have immediate relief, and the protection of an interlocutory injunction. The injunction which a plaintiff obtains by decree, is not merely temporary, or until further orders, but extends to the whole duration of the patent privilege; and not only applies to the particular mode of infringement proved against the defendant, but to all other modes in which the patent privilege may be violated.