What is reissue?
Patent law states "On taking up an application for examination or a patent in a reexamination proceeding, the examiner shall make a thorough study thereof and shall make a thorough investigation of the available prior art relating to the subject matter of the claimed invention." This means that prior art could disqualify your application for a patent.How To Conduct a Patent Search
you can do a patent search online. The U.S. Patent and Trademark Office (1790 - Present) and Delphion (1974 - Present) both provide free online databases. You can searching using keywords or phrases that describes your invention. Look for common terms describing the invention and its function, effect, end-product, structure, and use. The results will list the title and number of all patents related to your keywords (l976 forward only). The title link will take you to the full text of the patent. You will not be able to do a complete search online for a pre-1976 patent unless you know the exact patent number. With online patent be sure to examine other referenced patents that the inventor has listed.Direct-Hire Professional Search
If you want to save lawyer fees and mark-ups, consider going directly to a patent search firm. Searchers are best found through inventor grapevines, inventor associations, or university intellectual property departments. In larger cities, you can also check the Yellow Pages under "patent searchers." But be careful not to fall into a trap set by some disreputable invention marketing organizations. They list themselves in the phone book under "patent searchers" with a toll-free number. This is another way they hook unsuspecting inventors into service contracts. Get all the facts up front. Some reputable searchers ask for money up front if they don't know you. This is understandable. Just be sure you get the cost of the search beforehand, and get—and check—references. The cost to search a utility patent in the Washington, D.C., area runs between $500 and $1,000. It is roughly $100 per hour for a competent search. Once the search has been completed, if you want to obtain an opinion on the patentability of your invention, add the cost of your lawyer. If you need to show a prospective licensee that your invention has a good shot at a patent or that it's unlikely to infringe on an existing product, a letter from competent patent counsel may do the trick.How long does patent protection last? (As of year 2005)
Utility and plant patents are granted for a term which begins with the date of the grant and usually ends 20 years from the date the applications were filed. You must make the timely payment of the appropriate maintenance fees. Design patents last 14 years from the date you are granted the patent. No maintenance fees are required for design patents.Why is classification so important?
While it is possible to search patents using keywords, the best way to conduct a comprehensive patent search is by classification. Classification helps bring together similar devices and concepts, even when different terms have been used to describe them. When a device is truly new, terminology is not set. For example, before personal computers a mouse was nothing more than a rodent. The inventor of the first "Computer Input and Display Control" would not have found related devices by searching the keyword "mouse." A classification is used both as a tool for finding patents (patentability searches), and for assisting in the assignment of patent applications to examiners for examination purposes. Classifications have definitions. Classifications have hierarchical relationships to one another.