基于一般均衡模型的最优专利保护期限分析与模拟

General Equilibrium Analysis and Simulation to the Optimal Duration of Patents

基于一般福利理论,将专利保护期限作为变量纳入到一般均衡分析模型中,对专利保护期限变化带来的社会福利、生产者剩余与消费者剩余变化进行数理分析。提出最优专利保护期限的一种实现条件和计算方法,并对最优专利保护期限的影响因素进行剖析,找到了上述计算方法与之前学者提出的比率检验法之间的关系。在此基础上,结合具体参数进行数值模拟验证。研究发现:社会福利水平随着专利保护期限的增加先提高在达到最大值后开始降低;最优专利保护期限是有限的,当边际社会福利等于边际净损失时,专利带来的社会净利润达到最大;最优专利保护期限与专利产品的供给、需求弹性有关,与需求的价格弹性成反比。不同类型专利的最优保护期限不同,产品技术更新快、生命周期短的专利技术应采用较短的保护期限,反之则应采用较长的保护期限;可通过控制专利保护期限和垄断价格来遏制企业非法垄断行为和不正当竞争行为。

Based on welfare theory, a mathematical analysis is carried out to the influences caused by patent duration changes on social welfare, producer and consumer surpluses, treating patent duration as a variable in the general equilibrium model. An achieving way and calculation method to the optimal patent duration is studied, so as the optimal patent duration＇s influential factors. The relation between the calculation method proposed and the existing ratio test method was found. All the mathematical findings are proved by numerical simulations by given parameters. The research find： Social welfare increases first and decreases then by the patent duration＇s improvement, and reaches its maximum at some point; The optimal patent duration is finite, social profit reaches maximum when the marginal social welfare equals marginal social cost; Due to the elasticity of patent＇s supply and demand, optimal duration has an inverse relation with the price elasticity of demand. The faster market updating speed and the shorter product life cycle of the patent, the shorter optimal duration should be; apart from these, illegal patent＇s monopoly and unfair competition can be regulated by law and practice through the patent duration and monopoly prices using the analysis of this paper.