Abstract: International convergence of patent protection breadth implies the standards of patent protection in each region would converge to the same level. This paper extends the model of optimal patents to explain the exist motives of this equilibrium and its convergence path. Firstly, the patent protection breadth is quantified to demonstrate its impact on innovative benefits, the amount of innovation and social welfare etc., and then in accordance with national selection, the reaction function of patent protection breath is calculated to obtain the Nash equilibrium result. The conclusion show that the optimal breath in a country is different with the variance of market size and innovative ability; meanwhile, the unified high standards of patent protection is the second-optimum results of the game among countries, which is propitious to countries advanced in technology to increase innovation earnings from overseas while it is detrimental to global welfare; the optimal protection standards maximizing global welfare is at an intermediate level of each region.

Key words: patent breadth, international convergence, innovation incentives, game equilibrium