Annual Maintenance of a Patent
If you want to protect your invention you should maintain patent annually (pay official annual fee) till the end of 20 years period of its validity
Payment of Annual Fee
To maintain your patent you need to pay the state official annual fee.
If the fee is not paid, the patent becomes invalid and any person can start using it within the period of its invalidity and get the right of subsequent use.
The patent can be renewed within three years period of non-payment of annual fee.
