A design patent application protects the ornamental appearance of an article of manufacture. Design patents do not cover how the invention works, rather how the invention looks. Rather than an involved detailed description of the invention, a design patent application relies exclusively on drawings of the invention’s appearance. Design patents can be used to protect, for example, the shape of a beverage bottle, the appearance of an electric guitar, the tread pattern on a shoe, etc. When a product is innovated in appearance and function, that product can be protected by both utility and design patents.
Rather than an involved detailed description of the invention, design patent applications rely exclusively on drawings of the invention’s appearance for the description and claims. As a result, the most important portion of a design patent application is the drawings themselves. The test for determining whether a design patent is infringed is whether the accused product would appear “substantially the same” as the patented design from the point of view of an ordinary observer.
Design patent applications are generally considered to be relatively narrow in scope and have a shorter lifespan than utility patents (15 years rather than 20 years). Despite these limitations, design patents are very effective tools for protecting products having innovative appearance, in that they prevent your competitors from copying the appearance of your products. Product appearance can often be as important, or even more important, to your customers as the functionality itself.