Manufacturers generally understand the importance of utility and trademark patents in protecting their designs from unfair competition and customer confusion. But the power of the design patent is sometimes overlooked. While the United States Patent Office has issued over ten million numbered utility patents, it has yet to reach one million design patents. My suggestion to manufacturers: Consider both for any new product, as recent federal decisions may be worth it.
Design patents lie at the intersection of regular utility and trademark patents. Like trade dress, a patentable design must be non-functional. But like utility patents, a design patent is granted as compensation for advancement in the technical arts, more specifically the art of product design. In other words, a competitor can infringe a design patent even though a customer would not be confused as to the origin of the product. Design patents are also generally difficult to invalidate, but it comes at a cost to establish infringement. In order to prove the infringement of a design patent, it must be shown that an ordinary observer familiar with the prior art would believe that the design of the product is substantially the same as the design illustrated in the figures of the patent. 
So what is the value of a design patent, then, if a competitor has to get so close to the design that an ordinary observer might believe they are much the same? For the most part, design patents protect against counterfeits or closely related competitors. In many industries, especially those facing global competition, such protection has significant value in itself. But perhaps just as important is that design patents can be used to protect a manufacturer’s aftermarket.
Once a manufacturer sells a product protected by a utility patent commercially, the manufacturer’s patent rights are said to be “exhausted”. Indeed, a patent holder is only entitled to benefit once from the sale of a patented product and must generally allow customers to freely repair the product and replace its parts without further authorization from the patent holder. . As the Supreme Court said: “In order to bring into play the monopoly conferred by the grant of the patent, it must, in effect, be a second creation of the patented entity…. Mere replacement of individual non-patented parts, one at a time, whether it is the same part over and over or successively different parts, is nothing more than the owner’s legitimate right to repair his property. However, while a utility patent covering only one part of a patentable device can be very difficult to obtain, a design patent is usually handy. By protecting the rooms of a patented device with design patents, a patentee can prevent competitors from marketing such parts on the patentee’s aftermarket.
At least that was the recent Federal Circuit held on July 23, 2019 in Automobile Body Parts Association c. Ford Global Technologies, LLC. In this case, Ford obtained a design patent covering the headlight of one of its cars. The Auto Body Parts Association wanted the court to declare the patent invalid so that it could market its own headlights to repair Fords already on the road. The Association argued that Ford’s design patent was invalid because it was primarily functional in that a replacement headlight would have to look the same to match the car. The court rejected this argument, finding that the need for replacement parts to match the rest of the vehicle is not the type of functionality that would render a design patent invalid. Ford retained its exclusive right to market matching headlights for its cars by skillfully using the design patent system.
Thus, design patents can fill a critical gap left by utility patents in order to protect a manufacturer’s aftermarket. This is just one of the reasons why I think design patents are destined to gain increasing importance in the years to come. Indeed, it is no coincidence that design patents took center stage in Apple v. Samsung’s most high-profile and largest patent litigation in recent years. This case went to the Supreme Court, resulting in an important opinion on damages related to design patents. While that move may be debated on another day, suffice it to say that the design patent star is certainly on the rise.