中文摘要：

在有专利情况下，开发了一个R＆D投资模型，结合R＆D投资过程的特点，把R＆D投资过程分为两个阶段，一个是研究阶段被模型为欧式期权，另一个是开发阶段被模型为永生美式期权，从而把R＆D项目投资机会模型为复合期权，给出了R＆D期权价值的解析评价公式和最优投资决策规则，并讨论专利宽度（Patent Breadth）R＆D期权价值和R＆D项目投资决策的影响。以及申请专利的条件．

英文摘要：

The investment model of R＆D project with patent is developed in the paper. The R＆D investment process divides into two stages by the characteristics of R＆D investment process. The research stage is considered as an European option. The development stage is considered as an American perpetual option. Therefore the investment opportunity in R＆D can be thought of as a compound option. The analytic valuation formula for the R＆D option and optimal investment policy are derived. It is discussed that the effect of the patent breadth on the R＆D option value and R＆D investment policy, and presents the condition to apply for a patent.