The Intersection of Design and Utility Patents: Navigating Concurrent Protection and Double Patenting Challenges

I. Introduction

The United States patent system provides inventors with distinct pathways to protect their innovations through both utility and design patents. While utility patents protect the functional aspects of an invention, design patents safeguard the ornamental features. This bifurcated approach to patent protection creates a complex landscape where the boundaries between functional utility and ornamental design often blur. Inventors frequently seek concurrent protection through both regimes, raising important questions about overlap, distinction, and the potential for impermissible double patenting.

This article examines the jurisprudential framework governing the interplay between design and utility patents, analyzes the evolving standards for determining double patenting in the design-utility context, and explores strategic considerations for practitioners seeking to maximize protection for their clients' innovations. Recent developments in Federal Circuit jurisprudence suggest a more permissive approach to concurrent protection, while maintaining vigilance against improper extension of patent monopolies.

II. Concurrent Protection Through Design and Utility Patents

A. Legal Basis for Concurrent Protection

There is no per se prohibition against applying for both a design and a utility patent on the same article.[^1] This fundamental principle recognizes that a single innovation may embody both functional and ornamental aspects deserving of protection under different statutory schemes. Accordingly, a device patentable as a manufacture may also give rise to a patentable design.[^2] Courts have consistently affirmed that a design patent and a utility patent may be issued on the same physical structure.[^3]

The coexistence of design and utility patents finds its statutory basis in the distinct requirements and purposes articulated in Title 35 of the United States Code. While 35 U.S.C. § 101 establishes utility as a prerequisite for patentability under the utility patent regime, 35 U.S.C. § 171 requires that designs be "ornamental" to qualify for design patent protection. These distinct statutory foundations provide the legal architecture for concurrent protection.

B. Illustrative Examples of Concurrent Protection

The courts and the Patent and Trademark Office have recognized numerous instances where both utility and design patents appropriately protect different aspects of the same physical embodiment. For example, both utility and design patents were obtained for color striations on the backer sheet of roofing shingles for the purpose of creating an appearance or illusion of depth in a flat shingle.[^4] The design patent protected the ornamental appearance of the striations, while the utility patent covered the functional aspects of creating an illusion of depth.

Other examples of successful concurrent protection include:

• Ergonomic handle designs that combine both functional gripping benefits and aesthetically pleasing contours
• Electronic device housings with both functional cooling elements and distinctive ornamental appearances
• Container closures with both innovative sealing mechanisms and unique visual designs
• Furniture pieces with both novel structural systems and distinctive ornamental features

C. Federal Circuit's Permissive Approach to Different Statutory Classes

The Federal Circuit has adopted a generally permissive approach to concurrent protection, taking the position that there can be no double patenting where the patents cover different statutory classes.[^5] This bright-line rule provides clarity for practitioners but has been subject to qualification in subsequent decisions.

More recently, the Federal Circuit refined its approach in In re Dembiczak, holding that the phrase "having facial indicia thereon" found in the claims of a pending utility application was not a reference that is "basically the same as the claimed design," the claimed design depicting particular details of facial indicia. Thus, the claims of the design patent were not obvious variants of the utility patent application for purposes of an obviousness-type double patenting rejection.[^6] This decision demonstrates the court's nuanced analysis of the relationship between design and utility claims.

III. Determining Impermissible Double Patenting in the Design-Utility Context

A. Evolution of Double Patenting Standards

Earlier decisions of other courts developed a more complex analytical framework, looking to whether the design and utility patents claimed separate, distinct patentable inventions. Under this approach, each such patent must claim a separate, distinct patentable invention. The mere use of the same design patent as the vehicle for describing the utility claimed in the utility patent is not dispositive.

The standards for determining impermissible double patenting in the design-utility context have evolved significantly over time. The historical approach focused on whether there was an improper extension of the patent monopoly beyond the statutory term. Modern jurisprudence has refined this analysis to focus on the relationship between the novel aesthetic effect and the novel function.

B. The "Identity of Features" Test

A key test that has emerged from the jurisprudence is what might be termed the "identity of features" test. Impermissible double patenting has been said to exist if the feature in which the novel aesthetic effect resides is the identical feature which produces the novel function, such that a structure embodying the utility invention would of necessity embody the design, and vice versa.

This test recognizes that when the same features serve both ornamental and functional purposes, allowing separate patents could effectively extend the monopoly on those features beyond the statutory term of either patent type alone. The test provides a principled basis for distinguishing between permissible concurrent protection and impermissible double patenting.

C. Corollary Principles and Their Application

Cases have articulated several corollary principles that guide the double patenting analysis:

1. Double patenting exists if the design claimed in the first-to-issue patent cannot be employed without infringing the utility patent, and
2. Double patenting has not occurred if the second-to-issue utility patent encompasses designs other than identical subject matter if one of the claims being compared could be literally infringed without literally infringing the other.

These corollaries merely state extensions of the basic standard and can only be properly applied with reference to it. Courts have emphasized that double patenting in the design-utility situation cannot turn on niceties of precise ornamentation, but rather must turn on the presence or absence of design features which produce the novel function claimed in the utility patent.

If narrow decorative variations which contribute in no way to the novel function were allowed to enter the inquiry, it would become virtually impossible to ever find double patenting in the design-utility situation.[^7] The Seventh Circuit's decision in Ropat Corp. v. McGraw-Edison Co. provides a particularly cogent analysis of this principle, emphasizing the need to focus on substantive overlap rather than superficial distinctions.

D. The "Cross-Reading" Approach

In more recent jurisprudence, the Federal Circuit has articulated the concept that impermissible double patenting in design/utility situations exists if the two patents "cross-read."[^8] This approach asks whether each patent would necessarily infringe the other, focusing on the essential claimed features rather than incidental aspects.

The cross-reading approach represents a pragmatic attempt to distill the complex relationship between design and utility patents into a workable standard. However, its application requires careful consideration of the scope of the claims and the essential features protected by each patent.

IV. Judicial Application: Examples of Double Patenting Cases

A. Cases Finding Impermissible Double Patenting

Courts and the Patent Office have found impermissible double patenting in various contexts where the design and utility patents protected essentially the same innovation. These cases illustrate the application of the principles discussed above:

1. Rejection of utility claims for a fluorescent light bulb has been sustained in view of a previously issued design patent for the same device.[^9] In Application of Thorington, the Court of Customs and Patent Appeals found that the utility claims covered the same essential features as the design patent.

2. Rejection of utility claims for a finger ring in view of an earlier issued design patent has been sustained.[^10] The Application of Phelan decision emphasized that the utility claims did not add any substantive innovation beyond what was already protected by the design patent.

3. Rejection of a design claim for a flashlight cap and hanger ring in view of a utility patent has been sustained.[^11] In In re Barber, the court found that allowing both patents would effectively extend the monopoly on the same essential features.

4. Rejection of utility claims covering a balloon tire construction has been sustained in view of an earlier issued design patent.[^12] The In re Hargraves decision illustrates the application of double patenting principles to tire technology.

B. Cases Finding Permissible Concurrent Protection

Not all cases involving both design and utility patents result in findings of double patenting. Courts have allowed concurrent protection where the patents protect distinct aspects of the same physical embodiment:

1. The mere fact that a utility patent illustrates its claims with designs covered by a design patent was held not in and of itself dispositive of double patenting.[^13] This principle from Adidas Fabrique De Chaussures De Sport v. Andmore Sportsware Corp. recognizes that illustrations in patents do not necessarily indicate claim scope.

2. Several decisions have upheld concurrent protection where the design patent protects ornamental features that are separate and distinct from the functional innovations protected by the utility patent.

3. The Federal Circuit's recent jurisprudence has generally been more permissive of concurrent protection, particularly where the patents issue from applications filed at different times.

V. Strategic Considerations for Patent Practitioners

A. Priority Claims Between Design and Utility Applications

Understanding the relationship between design and utility applications extends beyond double patenting concerns to priority claims. A claim for priority under 35 U.S.C.A. § 120 may be made in a utility application based upon an earlier filed design application, provided that the design application satisfies the statutory condition. Of particular pertinence is the condition that the disclosure of the design application must meet the requirements of the first paragraph of 35 U.S.C.A. § 112 as applied to the claims of the utility application.[^14]

This principle has significant strategic implications for practitioners seeking to establish an earlier priority date for utility applications. However, practitioners must carefully consider whether the design application provides adequate written description and enablement support for the utility claims.

B. The "Same Invention" Analysis

Utility and design patents need not each claim every incidental feature of the other in order for them both to claim the "same invention."[^15] This principle from Transmatic, Inc. v. Gulton Industries, Inc. recognizes that patents may claim the "same invention" for double patenting purposes even if the claims do not perfectly mirror each other.

The "same invention" analysis requires a careful comparison of the essential features claimed in each patent rather than a mechanical comparison of claim language. This nuanced approach allows courts to identify substantive overlap while acknowledging the different claiming conventions in design and utility patents.

C. Functional vs. Ornamental Considerations

That the shape or configuration of a design is compatible with a functional objective does not in and of itself preclude its patentability as a design, at least so long as there are a myriad of alternatives and variables.[^16] This principle acknowledges the reality that design features often serve both ornamental and functional purposes.

The existence of alternative designs that could achieve the same functional result provides strong evidence that a design is not dictated solely by function. Practitioners should document and preserve evidence of alternative designs to bolster arguments for the ornamental nature of design features.

D. Judicial Recognition of Analytical Challenges

At least one court, in recognizing the difficulties involved in segregating design from utility aspects of an article, has indicated that the standard for determining whether there is impermissible double patenting in a design/utility context should not be too rigorous.[^17] This recognition in Wahl v. Rexnord, Inc. acknowledges the inherent challenges in applying double patenting doctrine to the design-utility interface.

The court's recognition of these challenges suggests a degree of judicial humility in approaching these complex determinations. Practitioners may find courts receptive to nuanced arguments that acknowledge the difficulty of precisely delineating ornamental and functional aspects.

VI. The Distinct but Overlapping Protection Regimes

A. The Proper Scope of Design Patent Protection

While design patents are not intended to protect mechanical function, or to secure a monopoly in any given mechanism or manufacture as such, it is immaterial that the subject of a design may embody a mechanical function, provided that the design per se is pleasing, attractive, novel, useful, and unobvious. It is the design that is patented, not the mechanism dressed in the design.[^18]

This principle from J. G. Furniture Co. v. Liton Bus. Systems, Inc. establishes that the mere presence of functional aspects does not disqualify a design from protection. Instead, the focus remains on whether the design, considered as a whole, presents an ornamental appearance worthy of protection.

B. Cross-Application of Prior Art

Although there are different statutory bases and standards for utility and design patents, no similar distinction exists when determining what constitutes relevant prior art for these types of patents. Consequently, a design patent may be applied as prior art against the claims of a utility patent application.[^19] This principle from Application of Aslanian has significant implications for prior art searches and patentability analyses.

The cross-application of prior art between design and utility patents reflects the reality that the prior art landscape does not neatly divide into ornamental and functional categories. Practitioners must consider both design and utility patents when conducting prior art searches, regardless of which type of protection they seek.

C. Terminal Disclaimers as a Practical Solution

In cases where double patenting concerns arise, terminal disclaimers often provide a practical solution. By disclaiming the terminal portion of the later-expiring patent, the patentee can eliminate concerns about extending the patent monopoly while still maintaining both patents.

The use of terminal disclaimers has become increasingly common in the design-utility context, particularly as the Federal Circuit has refined its approach to obviousness-type double patenting. Practitioners should consider proactively filing terminal disclaimers to address potential double patenting rejections.

VII. Recent Developments and Future Trends

A. Impact of Design Patent Term Extension

The extension of the design patent term from 14 years to 15 years following the implementation of the Hague Agreement has introduced new considerations in the double patenting analysis. The longer term for design patents may increase concerns about patent term extension through concurrent filing.

Practitioners should carefully consider the implications of the different terms for design and utility patents when developing filing strategies. In some cases, the extended design patent term may provide advantages over utility patent protection.

B. International Harmonization Considerations

As the United States continues to harmonize its patent system with international norms, the treatment of design and utility patents may evolve. Many foreign jurisdictions employ different approaches to the design-utility interface, potentially influencing domestic jurisprudence.

The implementation of the Hague Agreement represents a significant step toward international harmonization in design protection. Future developments may further align U.S. practice with international standards, potentially affecting the analysis of concurrent protection.

C. Emerging Technologies and New Challenges

Emerging technologies, such as graphical user interfaces, artificial intelligence-generated designs, and 3D printing, present new challenges for the design-utility interface. These technologies often blur the boundaries between ornamental and functional aspects in novel ways.

Courts and the Patent Office will likely need to adapt existing doctrines to address these new technological contexts. Practitioners should stay abreast of developments in these areas to effectively advise clients on protection strategies.

VIII. Conclusion

The interface between design and utility patents represents a complex area of patent law where careful navigation is required. While concurrent protection is generally permissible, practitioners must be vigilant about potential double patenting issues, particularly where the same features serve both ornamental and functional purposes.

The evolving jurisprudence in this area reflects the courts' ongoing efforts to balance the legitimate interests of inventors in securing comprehensive protection against the public interest in preventing improper extensions of patent monopolies. By understanding the principles and tests that have emerged from this jurisprudence, practitioners can develop effective strategies for maximizing protection while avoiding double patenting pitfalls.

As technology continues to evolve and the boundaries between form and function become increasingly blurred, the importance of a sophisticated understanding of the design-utility interface will only grow. This area of patent law will likely continue to develop in response to new technological challenges and international harmonization efforts.

[^1]: Liqui-Box Corp. v. Reid Valve Co., Inc., 16 U.S.P.Q.2d (BNA) 1848, 1855, 1990 WL 261394 (W.D. Pa. 1990) (six-gallon rectangular polycarbonate bottle).

[^2]: Application of Dubois, 46 C.C.P.A. 744, 262 F.2d 88, 120 U.S.P.Q. (BNA) 198 (1958). Compare In re Barber, 23 C.C.P.A. 834, 81 F.2d 231, 28 U.S.P.Q. (BNA) 187 (1936). See also Ex Parte Schlumbohm, 94 U.S.P.Q. (BNA) 393, 1952 WL 4876 (Pat. & Trademark Office Bd. App. 1952); Anchor Hocking Corp. v. Eyelet Specialty Co., 377 F. Supp. 98, 183 U.S.P.Q. (BNA) 87 (D. Del. 1974); Mr. Hanger, Inc. v. Cut Rate Plastic Hangers, Inc., 372 F. Supp. 88, 181 U.S.P.Q. (BNA) 850 (E.D. N.Y. 1974).

[^3]: Clark Equipment Co. v. Keller, 197 U.S.P.Q. (BNA) 83, 121, 1976 WL 21027 (D.N.D. 1976), judgment aff'd in part, rev'd in part on other grounds, 570 F.2d 778, 197 U.S.P.Q. (BNA) 209 (8th Cir. 1978). See, generally, Mesley, "Design and Mechanical Patents Relating to the Same Subject Matter," 44 J. Pat. Off. Soc'y 309 (1962); Gambrell, "Mechanical and Design Inventions: Double Patenting Rejections and the Doctrine of Election," 45 N.Y.U. L. Rev. 441 (1970).

[^4]: Elk Corp. of Dallas v. GAF Bldg. Materials Corp., 45 U.S.P.Q.2d (BNA) 1011, 1997 WL 796004 (N.D. Tex. 1997). See U.S. Patent No. 5,369,929; U.S. Des. Patent No. 344,144.

[^5]: Studiengesellschaft Kohle mbH v. Northern Petrochemical Co., 784 F.2d 351, 228 U.S.P.Q. (BNA) 837 (Fed. Cir. 1986), cert. dismissed, 478 U.S. 1028, 106 S. Ct. 3343, 92 L. Ed. 2d 763 (1986).

[^6]: In re Dembiczak, 175 F.3d 994, 1002, 50 U.S.P.Q.2d (BNA) 1614, 1619 (Fed. Cir. 1999).

[^7]: Ropat Corp. v. McGraw-Edison Co., 535 F.2d 378, 382, 191 U.S.P.Q. (BNA) 556, 558-59 (7th Cir. 1976).

[^8]: Carman Industries, Inc. v. Wahl, 724 F.2d 932, 939–40, 220 U.S.P.Q. (BNA) 481, 487 (Fed. Cir. 1983).

[^9]: Application of Thorington, 57 C.C.P.A. 759, 418 F.2d 528, 163 U.S.P.Q. (BNA) 644 (1969).

[^10]: Application of Phelan, 40 C.C.P.A. 1023, 205 F.2d 183, 98, 98 U.S.P.Q. (BNA) 156 (1953).

[^11]: In re Barber, 23 C.C.P.A. 834, 81 F.2d 231, 28 U.S.P.Q. (BNA) 187 (1936).

[^12]: In re Hargraves, 19 C.C.P.A. 784, 53 F.2d 900, 11 U.S.P.Q. (BNA) 240 (1931).

[^13]: Adidas Fabrique De Chaussures De Sport v. Andmore Sportsware Corp., 578 F. Supp. 1569, 1574–75, 223 U.S.P.Q. 1109, 1111 (S.D.N.Y. 1984).

[^14]: Ex Parte Duniau, 1 U.S.P.Q.2d (BNA) 1652, 1654, 1986 WL 83327 (Bd. Pat. App. & Interferences 1986). See § 15:6, infra.

[^15]: Transmatic, Inc. v. Gulton Industries, Inc., 442 F. Supp. 911, 196 U.S.P.Q. (BNA) 788 (E.D. Mich. 1977), judgment rev'd on other grounds, 601 F.2d 904, 202 U.S.P.Q. (BNA) 559 (6th Cir. 1979).

[^16]: John O. Butler Co. v. Block Drug Co., Inc., 620 F. Supp. 771, 226 U.S.P.Q. (BNA) 855, 859 (N.D. Ill. 1985); Bergstrom v. Sears, Roebuck and Co., 496 F. Supp. 476, 489, 207 U.S.P.Q. (BNA) 481, 494-95 (D. Minn. 1980).

[^17]: Wahl v. Rexnord, Inc., 624 F.2d 1169, 1181, 206 U.S.P.Q. (BNA) 865, 872 (3d Cir. 1980).

[^18]: J. G. Furniture Co. v. Liton Bus. Systems, Inc., 436 F. Supp. 380, 388, 194 U.S.P.Q. (BNA) 483, 490-91 (S.D. N.Y. 1977).

[^19]: Application of Aslanian, 590 F.2d 911, 200 U.S.P.Q. (BNA) 500 (C.C.P.A. 1979).