The treatment of functional features in design patents was discussed in the recent Federal Circuit case for Sport Dimension, Inc. v. The Coleman Company, Inc., Case No. 15-1553 (Fed. Cir. 2016).  The Court rejected the district court’s claim construction, which completely removed functional features.

As noted by the Court, “[a] design patent cannot claim a purely functional design—a design patent is invalid if its overall appearance is ‘dictated by’ its function. But as long as the design is not primarily functional, ‘the design claim is not invalid, even if certain elements have functional purposes.'”  Id, at 5. “Where a design contains both functional and nonfunctional elements, the scope of the claim must be construed in order to identify the non-functional aspects of the design as shown in the patent.”  Id, at 6.

The district court adopted claim construction that eliminated the left and right armbands and the side torso tapering, and also found the armbands, armband attachments, shape of the armbands, tapering of armbands, and tapering of the side torso to be elements that were functional rather than ornamental.  Id, at 4. The Patent Owner’s design and the competitor’s design are shown below:

Figs. 1 & 2

United States Design Patent No. D623,714 (Id, at 2).


Life vest front   Life vest back





Competitor’s Design (Id, at 3).

In three prior cases, courts used claim construction to “assist a finder of fact in distinguishing between functional and ornamental features,” but none of these cases entirely eliminate a structural element (that also had a functional purpose) from the claimed ornamental design.  Id, at 7.  The Court noted that while the following factors are for determining whether a claimed design is dictated by function and invalid, they may provide useful guidance to claim construction functionality:

  • whether the protected design represents the best design
  • whether alternative designs would adversely affect the utility of the specified article
  • whether there are any concomitant utility patents
  • whether the advertising touts particular features of the design as having specific utility
  • whether there are any elements in the design or an overall appearance clearly not dictated by function

Id, at 8.