Patent Protection, Technological Change and Wage Inequality

We develop a directed-technological-change model to address the issue of the optimal patent system and investigate how the optimal patent system influences the direction of technological change and the inequality of wage, where patents are categorized as skill- and labor-complementary. The major results are: (i) Finite patent breadth maximizes the social welfare level; (ii) Optimal patent breadth increases with the amount of skilled (unskilled) workers; (iii) Optimal patent protection is skill-biased, because an increase in the amount of skilled workers increases the dynamic benefits of the protection for skill-complementary patents via the economy of scale of skill-complementary technology; (iv) Skill-biased patent protection skews inventions towards skills, thus increasing wage inequality; And, (v) international trade leads to strong protection for skill-complementary patents, hence increasing skill premia.