Design patents are based on the ornamental aspects of surface decoration, aesthetic configuration, appearance and shape of an item. In contrast to a utility patent, a design patent is issued for aesthetic features for a new or an improved outward appearance; however, the subject claimed in the design patent should have some practical utility.
To be eligible for a design patent, the subject must satisfy the ornamental standards and be novel. When viewed through the eyes of an imaginary designer skilled in the art, the design must be non-obvious compared to any previously available design. Also, a design patent cannot be obtained for ornamental configurations that are not visible when the product is in use.
The prior art search for a design patent requires a close look at the ornamental aspects in any existing designs similar to the new design attempting to be patented. In essence, it is a visual search through volumes of classification binders at the USPTO. Due to the fact that design patents have minimal words defining the aspects of the design, a prior art search mainly involves design class codes and only broad keywords gathered after the typical USPTO design patent claim of “The ornamental design for…”
It is possible to obtain a design patent as well as a utility patent for the same invention if each patent type fulfills the respective patent standards. In such cases separate utility and design searches have to be performed.
An object with a design that is substantially similar to the design claimed in a valid design patent cannot be made, used, sold, copied or imported into the United States. A substantially similar copy is liable for patent infringement. In the case of a conflict, to detect infringement, evaluation of a patented design compared to an accused design involves satisfying the "Ordinary Observer" test, which was introduced by the United States Supreme Court case Gorham Co. v. White, 81 U.S. 511 (1871).
According to Gorham’s “Ordinary observer” test, there is infringement "if in the eye of an ordinary observer, giving such attention as a purchaser usually gives, two designs are substantially the same, the resemblance is such as to deceive such an observer, inducing him to purchase one supposing it to be the other."
This "ordinary observer" test is similar to the trademark infringement conditions i.e. whether there is a "likelihood of confusion." The patented and accused designs in the case of Gorham Co. v. White were both silverware handle designs. The attempts of the defendant, White, to establish the dissimilarity between the two designs was eventually ignored
Originating with Litton Systems, Inc. v. Whirlpool Corporation, 728 F.2D1423 (1984), the Federal Circuit added to Gorham’s “ordinary observer” test a second test i.e. "point of novelty" test required to deal with design patent infringement suits. i.e. the accused device contains 'substantially the same points of novelty as the patented design that differentiated the patented design from the prior art’.
On September 22, 2008, the Court of Appeals for the Federal Circuit in Egyptian Goddess, Inc. v. Swisa, Inc. (Fed. Cir. Dkt. No. 2006-1562) added conditions to the "ordinary observer" test established by the Supreme Court in 1871. The Federal Circuit provided guidance that will likely benefit design patent plaintiffs. Egyptian Goddess suit alleged that Swisa had infringed its U.S. Design Patent No. 467,389 that claims a design for a nail buffer, consisting of a rectangular, hollow tube having a generally square cross-section and featuring buffer surfaces on three of its four sides.
However, Swisa’s product consists of a rectangular, hollow tube having a square cross-section, but featuring buffer surfaces on each of its four sides.
The Federal Circuit observed that the difference of buffer surfaces in three sides in the design patent and buffer surfaces in all four sides in the Swisa buffers cannot be considered minor.
Much to the relief of many practitioners, the Federal Circuit found it difficult to implement the “point of novelty” test to a design patent because of the fact that it is difficult to provide a detailed verbal description of the claimed design. The Federal Circuit giving the decision for non-infringement unanimously held that the "ordinary observer" test was the sole test to determine design patent infringement, with the limitation that the ordinary observer is one with knowledge of the prior art. The ordinary observer test requires one to look for substantial similarity between the patented design and the accused design; but familiarity with the prior art is needed if the observer is to meaningfully compare the accused devices to the patented claim to evaluate the differences from previous designs.