How do patents differ from trade secrets?
There is a tension between the notion of trade secrets and patents. One approach to protecting intellectual property is to hold everything as a trade secret. The decision to apply for a patent includes necessarily a decision to take some fraction of one’s trade secrets and to give them away, in return for the grant of a patent.
The decision to apply for a patent does not necessarily require giving up all of one’s trade secrets, however. One might have trade secrets on inventions A, B, and C, and applying for a patent on C might not require giving up the trade secret status of A and B. However, to obtain a U.S. patent on C, it is necessary that the application contain (1) enough to enable one skilled in the art to practice C and (2) the best mode known to the applicant for practicing C. This might require revealing A and B in the application. If so, it would probably make sense to seek patent protection on A and B as well as on C. Depending on the time sequence, one could patent an invention and simultaneously keep secret an improved version of the invention. For example, if a patent application for invention A is filed, and if an improvement A+ is conceived after the filing of the patent application on A, the improvement A+ could be kept secret.
One should keep in mind, however, that it is difficult to keep information “secret” at a public institution. Generally, we do not deal with trade secrets. Also, the U.S. Patent Office has announced plans to begin publishing patent applications 18 months after filing.