关键词: 技术创新, 分布结构, 演变, 专利, 美国, technological innovation, distribution structure, evolution, patent, the U.S.

Abstract: This paper constructs an analysis framework of time-filed, and analyzes the distribution structure evolution of the U.S. technological innovation base on the patent data of 1963-2008. Firstly, the result shows that the distribution structure of the U.S. technological innovation fields gradually concentrates on just a few technology fields from 1963 to 2008 with the approach of rank-frequency and concentration ratio. In recent years, it always maintains in the “5-55” pattern. That is to say, the patents of top 5 technology fields which have the most utility patents account for about 55% of all the utility patents in the U.S.. Then, according to the total patents and the relative growth rate of each technology innovation field, we divide them into 4 development patterns which are leading-growth, emerging-growth, leading-maturity and germinative (recession)-sluggish. The result of CV (coefficient of variation) indicates that leading-growth and emerging-growth patterns develop unstably and the leading-maturity pattern develops relatively stably.