The difference between a design patent and a utility patent is that a design patent protects the ornamental design, configuration, improved decorative appearance, or shape of an invention. This patent is appropriate when the basic product already exists in the marketplace and is not being improved upon in function but only in style. For example, designer eyeglass frames, the original Coca-Cola bottles, and "Pet Rocks" would have all been protected with design patents. A U.S. design patent lasts for 14 years.
A utility patent protects any new invention or functional improvements on existing inventions. This can be to a product, machine, a process, or even composition of matter. For example, going from LED technology to OLED would call for a new utility patent. In this case the material of the light emitting diodes has gone from the synthetic material used in LEDs to organic material in OLEDs. Other examples would be a better carburetor, a new type of self-fastening diaper or a new recipe.
The life of a U.S. utility patent lasts 20 years from the date of filing assuming the patent is granted, but the owner of the patent must pay maintenance fees to the United States Patent and Trademark Office (USPTO) to keep a utility patent from expiring. These fees are due at 3½, 7½, and 11½ years and amount to roughly $3500 U.S. dollars for individuals and small businesses.
Before filing for a utility patent you might consider filing for a provisional utility application, which will set a filing date for the utility patent one year hence. This allows you a year to test interest in your invention or raise capital. If in a year you decide not to follow through, the application simply expires. If you want to go forward you will file a non-provisional utility patent, which is the same thing as a utility patent. This route essentially provides an additional year of patent pending status and protects you from spending money on a patent for an invention that isn't viable.
Once you've applied for a non-provisional patent -- whether following a provisional patent or not -- you will be issued patent pending status until the patent is granted, which can take up to 24 months.
Some ideas might require multiple patents, including both a utility and a design patent, or even multiple utility patents if, for instance, several functional improvements are made in a process or product.
To protect your invention in other countries you will need to file an international patent application under the Patent Cooperation Treaty (PCT). Though this does not provide you with an international patent it delays the expense of filing in other countries allowing you more time to access the feasibility of selling your invention abroad. Laws under the PCT allow you to file a single international patent application that will temporarily protect your invention in up to 117 countries for as long as 2½ years. Foreign patents should be discussed with a registered patent attorney.
Many people looking to obtain patents are tempted to use so-called "idea companies" that charge a fee to develop potential leads for your invention. Most patent attorneys will warn you away from the vast majority of these companies, as will consumer watchdog groups. Instead, once an invention is protected by patent pending status, or patent, many insiders suggest attending trade shows with a prototype to seek viable leads yourself.
Patents can protect the inventor from losing millions of dollars, should an invention be successful. For this reason it is recommended that anyone seeking a patent secure the services of a registered patent attorney, whose first step will be conducting a thorough search to see if someone has already patented your idea or invention.
To conduct a preliminary search yourself, you can visit the search section of the USPTO (http://www.uspto.gov/patft/). Enter a keyword to bring up results, then click on a patent to view it. By reading a few patents you can get an idea for how involved they are and why an attorney is a good idea. The USPTO can also help you find patent attorneys in your area.
Obtaining utility patents are rather expensive and can cost up to $8000 U.S. dollars or more, with attorneys fees. Design patents will be less. the USPTO website includes the fee schedule (but this does not include attorney's fees).