Forcing Patent Claims

46 Pages Posted: 21 Aug 2012 Last revised: 12 Feb 2015

See all articles by Tun-Jen Chiang

Tun-Jen Chiang

George Mason University School of Law

Date Written: August 16, 2012


An enormous literature has criticized patent claims for being ambiguous. In this Article, I explain that this literature miscomprehends the real problem. The fundamental concern with patent claims is not ambiguity (which may, or may not, lead to overbroad rights) but the fact that claims are drafted by patentees, who have self-serving incentives to write claims in a manner that will certainly lead to overbroad rights. To the best of my knowledge, no one has ever asked why the patent system permits self-interested patentees to have the leading role in delineating the scope of their own patent.

This Article makes two contributions to the literature. First, it explicitly frames the problem with patent claims as one of patentee mal-intent, rather than the intrinsic ambiguity of language. Second, it provides a counter-intuitive answer to the question of why the patent system relies on patentee-drafted claims. Although giving patentees the power of claim drafting undoubtedly leads to overbroad patent rights, this allocation of drafting power is nonetheless socially efficient. The reason is that the PTO and courts do not have enough information to determine the correct scope of a patent in the first instance. Requiring patentees to write claims forces them to take a position, which discloses some of the patentee’s private information and makes subsequent decision-making by courts and the PTO less complex. While patentees will over-claim, they cannot over-claim too much, and relying on an imperfect claim is better than having a court or the PTO make an uninformed guess in the first instance. The Article then explains the implications of this insight for the debate over claim interpretation.

Keywords: claim interpretation, patent scope, central claiming, peripheral claiming, adhesion contracts, Pacific Gas, Autogiro

JEL Classification: O34

Suggested Citation

Chiang, Tun-Jen, Forcing Patent Claims (August 16, 2012). 113 Michigan Law Review 513 (2015), George Mason Law & Economics Research Paper No. 12-51, Available at SSRN: or

Tun-Jen Chiang (Contact Author)

George Mason University School of Law ( email )

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