Design Patent Claim Construction

Design patent claims protect the ornamental design of an article of manufacture. Unlike a utility patent, which covers functional aspects, a design patent focuses on the visual appearance, including the shape, configuration, or surface ornamentation of the claimed design. A design patent has a single claim that refers to the design patent drawings that illustrate the design, which serve as the primary basis for determining the scope of protection.

Infringement of a design patent occurs when an unauthorized party makes, uses, sells, or imports an article embodying a design that is substantially similar to the claimed design in the eyes of an ordinary observer. The primary test for design patent infringement is the "ordinary observer" test, established by the Supreme Court in Gorham Co. v. White. Under this test, if an ordinary observer, familiar with the prior art, would be deceived into thinking that the accused product is the same as the patented design, then infringement has occurred.

The Federal Circuit in Egyptian Goddess, Inc. v. Swisa, Inc. reaffirmed that the ordinary observer test is the sole test for determining design patent infringement. This approach focuses on the overall visual impression of the design rather than specific differences, ensuring that minor variations do not circumvent patent protection. Therefore, to avoid infringing a design patent, a competing design must create a distinctly different visual impression to an ordinary observer. The infringement is analyzed after the scope of the design patent claim is determined by a claim construction process.

Federal Circuit Guidance on Design Patent Claim Construction


This article provides explanation of design patent claim construction and the impact of the Federal Circuit decision in Curver Luxembourg SARL v. Home Expressions Inc.

Key Points:

  1. Claim Language Importance: The article stresses that the words of a design patent claim can limit the scope and should not be ignored. This is a departure from the previous approach where the drawings primarily determined the patent's scope.
  2. Impact on Design Patent Practice: The decision could make it easier to procure and defend design patents with broader scope but complicate enforcement against infringing products that do not match the specified article of manufacture.
  3. Prosecution History: The prosecution history played a crucial role in limiting the patent's scope in this case. The amendments made during prosecution to specify the article of manufacture (chair) were decisive in the court's ruling.
  4. Future Implications: The decision is expected to lead to more detailed and potentially contentious claim construction arguments based on the language of design patent claims, not just the drawings.

Practical Guidance:

  • Patent practitioners should ensure that the description of the article of manufacture in a design patent application accurately reflects the intended scope of protection and aligns with the drawings.
  • During prosecution, careful consideration must be given to any amendments to avoid unintended limitations on the scope of the claimed design.

Claim Construction Process

Design patent claim construction involves interpreting the scope and meaning of a design patent's claim to determine the extent of its protection. This design patent claim construction process is conducted by the district court judge in design patent litigation. The district court examines the design patent claim, considering the visual disclosure of the design provided in the design patent drawings. The claim scope is primarily defined by the visual elements of the design drawings. However, in the context of a patent trial, the district court also considers the impact of functional features of the design on the scope of the claimed design. Functional aspects are generally not protectable in a design patent. Therefore, the court distinguishes between functional features and ornamental design elements to ensure that the claim scope is appropriately limited to non-functional aspects.

Role of Prior Art

Prior art also plays a significant role in design patent claim construction. The district court evaluates prior art to ascertain the novel aspects of the claimed design. During patent litigation, if the prior art discloses similar designs, the court may narrow the claim scope to avoid overlap of the design with the prior art, ensuring that the patented design is novel and distinct from the prior art.

Federal Circuit Decision in Egyptian Goddess

In Egyptian Goddess, the Federal Circuit explained and reinforced that the "ordinary observer" test is the test for infringement. This test requires considering whether an ordinary observer, familiar with the prior art, would find the claimed design and the accused design to be substantially similar. The ordinary observer is assumed to be familiar with the prior art. Thus, the district court defines the claim scope in a manner that accurately reflects the ornamental nature of the design while excluding functional features and features that were previously disclosed in the prior art to provide an appropriately narrow construction. Design patent claim construction thus involves a detailed analysis of the visual disclosure, consideration of functional features, and evaluation of prior art.

Role of Claim Language

The scope of a design patent claim is also defined by the claim language of the design patent. In teh Curver Luxembourg case, the Federal Circuit held that the claim language, not just the drawings, limits the scope of a design patent. This decision emphasizes that the claim language, and also the title and text of the design patent can restrict the application of the design to a specific article of manufacture, such as a chair, even if the drawings do not depict the article itself.

Case Summary:

The case revolves around the design patent D677,946, owned by Curver Luxembourg SARL, which claims an "ornamental design for a pattern for a chair." The dispute arose when Home Expressions Inc. marketed baskets with a similar overlapping Y-shaped design pattern as claimed in Curver's patent. Curver alleged design patent infringement, but the district court dismissed the case, and the Federal Circuit affirmed the dismissal.

Design Patent Drawing

Key Holdings:

  1. Claim Language Limitation: The court held that the claim language "ornamental design for a pattern for a chair" limits the scope of the design patent to chairs only. The baskets marketed by Home Expressions, which incorporated the same design pattern, did not infringe the patent as they were not chairs.
  2. Patent Scope Determination: The decision marked a shift by emphasizing that the claim language, not just the drawings, limits the scope of a design patent. This ruling underscores the importance of the words used in a design patent claim.
  3. Historical Precedent: The decision aligned with long-standing precedent that design patents are granted for designs applied to specific articles of manufacture, not for designs in the abstract.
  4. Prosecution History Estoppel: The prosecution history indicated that Curver amended the claim and title to specify a chair to meet the article of manufacture requirement, further cementing the limitation of the design to chairs.

Implications Claim Scope and Design Patent Infringement:

The Federal Circuit decision in the Curver Luxembourg case places new emphasis on the interpretation of claim language of a design patent. While decision ensures that design patents are tied to specific articles of manufacture, it may complicate infringement analysis, in which the district court may find a precise meaning of claim language. A design patent claim is traditionally a formal requirement that simply refers to the design patent drawings. Patent practitioners must now carefully draft the design patent claim to address the article of manufacture requirement.

Prosecution of Design Patents at the United States Patent and Trademark Office

The Curver Luxembourg case has significant implications for prosecuting design patent applications at the United States Patent and Trademark Office (USPTO). This case emphasizes the importance of clear claim language in design patent applications. The Curver Luxembourg case illustrated that claim language specifying the article of manufacture can limit the scope of the design patent, even if the article is not depicted in the drawings. A patent examiner must ensure that the design claim aligns with the specific article described in the design patent specification.

Patent law, particularly 35 U.S.C. 112, requires that the design patent application provides a written description that clearly identifies the article of manufacture. For example, a design patent for a two-dimensional surface ornamentation must clearly specify the article of manufacture it is applied to, preventing overly broad interpretations of the design's scope. This clarity helps the patent examiner evaluate the novelty and non-obviousness of the claimed design in light of prior art. For example, had the patent application discussed a woven textile as the article of manufacture, the claim scope may have been broader than it was construed in the Curver Luxembourg case. Therefore, patent practitioners must carefully define the article of manufacture in a design patent application to avoid limitations on the claim scope. Patent examiners, guided by this case, will scrutinize the consistency between the design claim and the drawings, ensuring compliance with the requirements highlighted by the Federal Circuit in the Curver Luxembourg case.

The Curver Luxembourg case reinforces the necessity for a carefully considered definition of the article of manufacture in a design patent application. This definition guides the patent examiner in their assessment of compliance with 35 U.S.C. 112 and a carefully defined article of manufacture may allow for a favorable determination of the design patent claim.


The Curver Luxembourg case and the accompanying analysis underscore the critical role of claim language in design patent claims. The Federal Circuit's decision to limit the scope based on the specified article of manufacture (a chair) rather than the abstract design has significant implications for how design patents are prosecuted and enforced. Practitioners should take heed of this ruling to draft clear and deliberate descriptions of the article of manufacture in a design patent and carefully navigate the prosecution history to avoid restrictive interpretations of the patent's scope.

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