The scope of a design patent claim must be construed to identify the ornamental and functional aspects of the design, and applying the ordinary observer test, the trier of fact must determine whether the deception that arises is a result of the similarities in the overall design, not of similarities in ornamental features in isolation.

Richardson v. Stanley Works, Inc., No. 2009-1354 (Fed. Cir. Mar. 9, 2010).

The district court construed the scope of a design a patent and, after a bench trial, entered a judgment of non-infringement. On claim construction, the district court factored out the functional aspects of the design and then concluded that the overall visual effect of the alleged infringer’s tools was not substantially similar to that of the patentee’s design. The Federal Circuit affirmed.

Although ordinarily, it is preferable not to construe a design patent, the distinction between ornamental and functional aspects of the design can be helpful to the trier of fact. A design patent, unlike a utility patent, limits protection to the ornamental aspects of the design, not the functional aspects. In this case, the design contains both ornamental and functional aspects, and thus, the design patent scope is limited to those ornamental aspects alone and does not extend to any functional aspects of the design. Thus, the district court properly factored out the functional aspects of the patentee’s design as part of its claim construction.

The ordinary observer test serves as the sole test for design patent infringement. Under the ordinary observer test, the patentee must establish that an ordinary observer, familiar with the prior art designs, would be deceived into believing that the accused product is the same as the patented design. In evaluating infringement, the courts must determine whether “the deception that arises is a result of the similarities in the overall design, not of similarities in ornamental features in isolation.” Using this test, the Federal Circuit agreed with the district court’s finding that “[f]rom the perspective of an ordinary observer familiar with the prior art, the overall visual effect of the [alleged infringing tools] is significantly different from the [patentee’s design].”

A copy of the opinion can be found here.