A U.S. design patent is a way to protect visual characteristic(s)of a physical product (e.g. bottle or any product). Said another way, a design patent protects certain visual or ornamental features of the way a product looks. In particular, the visual or ornamental characteristics (not the function of the product or how it works). Design patents include essentially images of the product. The novel ornamental features shown in the drawings is what is protected when you obtain a design patent.
Because a design is visual, the subject matter of a design patent application may point to the configuration or shape of the product, to the surface ornamentation applied, or to a combination of both configuration and shape ornamentation. The ornamentation cannot be separated from a product and cannot exist by itself. A design patent protects only the appearance of the product and not the structural or features that make it useful. You can file more than one patent covering the look of a particular product. Conversely, a utility patent only allows for one article per patent. Because utility patents cover function and protect against another from making, using, selling or importing into the United States any products that are covered by the utility patents, these types of patents are far more desirable and stronger. However, if the idea does not have a unique function but just looks different, then you need a design patent. You could also get more than one if the design is different, with all the designs looking differently enough to protect a different embodiment of the design. With multiple design patents, the design patent rights you obtain become stronger and more defensible.
An ornamental design in a design patent application can be embodied in the entire product or only a portion of the product. The design can also be just the surface ornamentation applied to a product. It is essential to have a professional design patent drafts person prepare the drawings as they must be as accurate a possible.
The design patent application contains only a single claim. If the designs are independent and distinct, they must be filed in separate applications because they will then not be supportable by a single claim.
A design for a product that is dictated by its function lacks ornamentality and is therefore not proper subject matter. Conversely, if the design had no unique or distinctive shape or appearance, you design is not considered proper subject matter. A design must be original, and a design that mimics a well-known or naturally occurring object or person is not original.
It should be noted that a design patent should be a part of an overall patent strategy.