What is a "stealth" invention?

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Patents for technologies that are buried deep within a product (stealth inventions) are often not useful, since it may be impossible to determine whether anyone is actually infringing the patent. For the patent to be valuable, it should not only cover features that provide a business advantage or distinguish a product from a competitor’s product; it should also cover features that have characteristics detectable by the patent owner. It is important to be able to determine relatively easily whether a competitor’s product utilizes the patented technology and thus infringes the patent.

For example, a computer program may execute a series of incredibly efficient calculations that produces some result. Although this calculation may be extremely novel and unique, having a patent on this calculation would not be useful if it was impossible to determine whether the computer was actually implementing the calculation. Although it is true that the patent owner would have the right to exclude others from practicing this stealth invention, it might be extremely difficult, if not impossible, for him to ever know whether an actual infringement was occurring. On the other hand, if as a result of the calculation a specific display was produced on the computer screen in which the display could only have been produced by the calculation, then patenting the calculation would be useful since it would be possible on simple inspection to know, by virtue of the display, whether the calculation was being infringed upon. So, an important aspect of deciding what to patent is the feasibility of detecting whether others are in fact infringing upon the patent.

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About the Author

John Ferrell is a founding partner of Carr & Ferrell LLP, one of Silicon Valley's foremost technology law firms, and specializes in patent and intellectual property law matters. He is the Chair of the firm's Intellectual Property Practice Group.