In general, "patent fee" refers to the annual fee of a patent, that is, the annual fee that a patent needs to pay from the time it is granted the patent right to the end of the patent protection period.
Patent application is generally to obtain a "patent right", which is an exclusive right, that is, the "exclusive right" granted by the state to the patentee. The patentee has the right to prohibit others from using his patented technology, the patentee has the right to demand economic compensation from those who use his patented technology, the patentee has the right to sign an implementation license contract with others to allow others to use his patented technology, and then get a certain royalty. The patentee can buy and sell his patented technology and get a certain economic return, but the premise of having the above rights is that the patentee makes his patented technology public. The specific way is that China National Intellectual Property Administration publishes the authorized patent documents online. In the language of the patent law, the above content is "changing the protection of this area for a certain period of time by announcement".
However, these rights are beneficial to the patentee. If the patentee wants to have these rights, he needs to pay a certain fee to the state, that is, the "annual fee", to ensure that when the patentee wants to use the above rights, the state will safeguard the patentee's rights in accordance with the corresponding laws. If the patentee thinks that the technology is not advanced and doesn't want to protect it in a certain year after the patent is granted, he can no longer pay the annual fee, which also means that the patentee gives up all the above rights and everyone can use his patented technology for free according to his published patent documents.
The design of patent annual fee also fully considers the income of the patentee. The cost in the first three years is relatively low, and then it is slightly higher in the fourth to sixth years, and then it will be increased. The purpose is that the patentee will not get much income in the next few years after authorization, so the annual fee will be less. With the extension of authorization time, it should get more and more income, so it should pay more and more fees to safeguard its patent right, so the annual fee will also increase.
In my opinion, if the patentee can't even pay the "annual fee" of the patent, or thinks it is an economic burden, it proves that the patentee has not made full use of his own patent to obtain economic benefits, which is not in line with the original intention of patent law legislation. In this case, it is not necessary for the patentee to continue to pay the annual fee, but to let the patented technology enter the public domain and let the public use the patented technology, thus promoting the technological development of society.