Legal analysis: 1. After the patent exceeds the protection period (the term of invention patent is 20 years, the term of utility model patent is 10 year, and the term of design patent is 15 year), the patent right is lost; 2. After the patent right is lost, the original technical scheme can be innovated or improved, and a new application for patent protection can be made.
Legal basis: According to Article 42 of the Patent Law of People's Republic of China (PRC), the term of invention patent is 20 years, the term of utility model patent is 10 year, and the term of design patent is 15 year, all of which are counted from the date of application.