From the September 1999 issue of Entrepreneur

Almost every good idea evolves over time. Take the airplane. It started as a one-man, open-air flying machine. But gradually changes occurred, making it better and more complex in form. Not surprisingly, thousands of patents have been granted on airplane improvements. And airplanes aren't the only invention to benefit from improvements made over time: According to Mark Gilbreth, a patent attorney at Gilbreth and Strozier in Houston, more than 90 percent of all patents granted today are improvement patents. So if you improve an existing product, it's very possible to receive a patent on that improvement. However, before you file your patent application, here's some important information you should know.

Passing the Tests

To receive an improvement patent, your idea must pass four tests:

Test #1: Is your idea patentable? To be considered patentable, the idea must fit into one of five "statutory" categories: process, machine, manufacture, composition or "new use" of one of the other four. Fortunately, these categories are extremely broad, so this part of the test is easy to pass. The few ideas that don't pass this first test include laws of nature and processes that use only the mind, such as meditation.

Test #2: Is the improvement useful? It's almost always possible to come up with a useful purpose for an invention. However, if your improvement is deemed immoral, illegal or unsafe, the U.S. Patent and Trademark Office (PTO) could refuse to award it a patent. For example, improving a shopping bag by lining it with lead for the purpose of protecting stolen items from security sensors wouldn't pass the test; that use is for illegal activity. Or if you improved pill capsules but the change caused cancer, your improvement would be deemed unsafe.

Test #3: Is your improvement new? This is called the novelty test. When a patent is denied on an improvement, most of the time it's because it didn't pass this test. In order to pass, your improvement must differ from all prior developments. (In patent law, this is called "prior art.") To prove your improvement is novel, you must collect all the information related to your improvement and explain why your idea is different from the previous ones. One way to do this is to perform a patent search on all existing patents to see if your improvement has been mentioned. If you can prove your improvement is indeed novel, you'll pass this test.

Test #4: Does your improvement provide a new and unexpected result? This test is awkwardly dubbed the unobviousness test. You must show that your improvement isn't obvious to someone with ordinary skill in the area of your improvement. For example, if you improved a piece of jewelry by replacing the garnet with a diamond, a jeweler would not find this improvement new and unexpected. But if your improvement allowed the piece of jewelry to be used as a can opener, that wouldn't be obvious to a jeweler and could qualify as patentable.

Don't Give Up

If your improvement doesn't pass the four tests, it's still possible to get patent protection, according to Robert M. Chiaviello Jr. and Jerry W. Mills, intellectual property attorneys at Baker & Botts LLP in Dallas. They say you can receive a patent for combining two elements. Here's their example: A charm bracelet and a miniature radio are each items that can't receive new patents. However, you could patent the idea of a charm bracelet that worked as a miniature radio (assuming the combination has not already been patented). Their point is that it may be possible to receive a patent for combining two nonpatentable items if the combination isn't obvious. "As long as the combination is novel and unexpected, there's a good chance you can receive a patent," says Mills.

Case in Point

Receiving a patent for your improvement doesn't mean you automatically have the right to sell your idea. If your improvement patent involves the use of an existing patented product, you may need a licensing agreement from the dominant patent holder.

I have firsthand experience with this issue. After I invented the TopsyTail, another inventor obtained a patent on an improvement to my idea. He added a sliding device to my product that adjusted the size of the loop. He then began selling his improved TopsyTail knock-off. I sued him for patent infringement. He had invented an improvement, but his product incorporated a TopsyTail and my method for turning a ponytail inside out, so he infringed on my patent. To legally sell his product, he first needed to obtain a licensing agreement from me.

Now, if this inventor's improvement to my product had been an accessory that could be attached to a TopsyTail, he could have sold it without obtaining my permission. After all, you'd need to own a TopsyTail to use his accessory, and I would have been compensated. His mistake was selling a product that was simply an improved version of my patented invention.

The lesson here is obvious: An improvement that can be added to an existing patented product without changing the original product is allowed; however, if you make or hire someone else to make the original patented product with your improvement incorporated into the design, you need a licensing agreement. It's always simpler, therefore, to make and sell an improvement as an accessory rather than as a modification to an existing product.

Room for Improvement

Make no mistake, creating an improvement to an existing idea is definitely inventive. Keep in mind, however, that when the PTO issues your patent, it doesn't classify your patent as a dominant or improvement patent. That means the responsibility rests on your shoulders to make sure you understand what you can and can't do regarding the marketing of your idea. As Chiaviello says: "To avoid possible litigation, it's best to sell an improvement product as an accessory. And, if your improvement alone is not patentable, combining it with another product can create a strong patent and additional protection."

Next Step

In addition to conducting a patent search, it's a good idea to consult with experts to verify your improvement is truly novel. Here's a list of people to talk to:

  • Salespeople and buyers in stores that sell the original device
  • Educators doing research in the field of your improvement
  • Engineers and technicians in companies in the same field as your improvement
  • Family and friends "in the business"

Picture This

If your invention is an improvement to a previously patented product, the drawings should show the improved portion disconnected from the original product. You should also show as little of the original product as necessary to illustrate how your improvement fits with it.


Tomima Edmark, the woman famous for her Topsy Tail invention has now turned her creative talents to the competitive retail arena of intimate apparel, HerRoom and HisRoom.