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.How to Conduct a Patent Search
To get a basic understanding of patent searches read Searching For Students and in particular read Searching Using Key Words . It was written for students; however, if you can look past the cute language it will quickly get you reading and searching patents online within minutes. It will not be enough to do a diligent (complete) search for prior art by only using the Internet. For that you would need to understand the patent classification system and be prepared to do days or even weeks of research.The Do-It-Yourself Patent Search
If you decide to do the patent search yourself, you have several search methods available: The USPTO (United States Patent Trade Office) Public Search Facility. The USPTO operates a Patent Public Search Facility located in Alexandria, Virginia. Here every U.S. patent granted since 1790 may be searched and examined. Many inventors like to make at least one pilgrimage to the Patent Public Search Facility. It's located fewer than 15 minutes from National Airport by taxi; Metro Rail serves it off the Blue and Yellow lines, King Street Station; and several hotels are within walking distance, so it's easy to get to and around.Patent Searching 101: A Patent Search Tutorial
Inventors and entrepreneurs who are looking to cut costs frequently want to do their own search. This is a wise first move, but you really need to be careful. It is quite common for inventors to search and find nothing even when there are things that could and would be found by a professional searcher. So while it makes sense to do your own search first, be careful relying on your own search to justify spending the thousands of dollars you will need to spend to ultimately obtain a patent. In other words, nothing in this article should be interpreted as me suggesting that inventors can or should forgo a professional patent search. There is simply no comparison between an inventor done patent search and a patent search done by a pro. Having said that, every inventor should spend time searching and looking if for no other reason than to familiarize themselves with the prior art. Of course, if you can find something that is too close on your own you save time and money and can move on to whatever invention/project is next. Another thing you MUST know about when you use Google Patent Search is that there are also some holes in the database. I have specifically looked for patents I know to exist and cannot always find them. I have heard the same experience from other patent attorneys and agents. Additionally, the most recent patents are not available on Google. What this means is you cannot only rely on Google, but you still must use Google. The Google database covers patents that are issued all the way back to US Patent No. 1. This scope is much broader than either Free Patents or the USPTO . So while you might not find everything, while it is difficult to specifically narrow your search, you still really need to check yourself using the Google database to see if there are old references that might be on point. In this case there are not many to choose from. Many times, however, the list will contain hundreds or even thousands of patents depending upon the popularity of the term or phrase selected. For example, if you search "SPEC/thermos", you will find hundreds of patents that use this word in the specification. In fact, at the time this sample search was conducted (March 16, 2012) no fewer than 970 US patents have the word "thermos" in the specification, and that is only for patents issued since 1976. So what should you do now? If you find too many patents, rework the specification field search. For example, if your search were "SPEC/thermos and SPEC/beverage" you get down to 200 US patents. Ultimately, upon receiving manageable results, just click on several of the patents. The key, however, is to start off broad and then narrow your way down to those that are the most likely relevant references. Also remember that it is critically important to figure out what things are called. I cannot stress this enough. You need to use different names and labels. You will find that patent attorneys typically call certain features by a select few names. These names are not always obvious, but once you figure out what the industry calls something you are far more likely to find relevant patents.More on Prior Art
Remember, while patent searching is a big part of prior art , it is not everything. If someone has made your invention before you without patenting that still counts against your patentablity. A complete search for prior art might include for example: searching non-patent literature such as any magazine, newspaper, or trade paper article written about inventions like yours also a complete search would include international patent documents (online) and not just those found at the USPTO. Do not make the mistake of believing that just because no one else is selling your product that it does not already exist. After determining that your idea is patentable and qualifies for a patent - you now need to decide if the expense of patenting is worth it.