For inventions involving the functionality of an apparatus, the United States has only a single type of patent while most other countries have two types.  The single type of patent available in the US is called a utility patent here, but essentially every other country calls it an invention patent (so that the term we will use in this article).  The type of patent which most foreign countries have in addition to invention patents, but for which the US has no equivalent, is called a utility model patent (or “petty patent,” “minor patent” or “innovation patent”).  Utility model patents can be incredibly useful in gaining foreign protection, but because the US has no equivalent most US practitioners don’t consider to recommend utility model patents to their clients.

The main reason utility model patents are so useful is because of their low cost.  Utility model patent applications are considerably cheaper to prepare, file, prosecute, and maintain than invention patents.  The preparation of a utility model patent application will generally cost $1000 to $2000, while the preparation of an invention patent application can cost anywhere from $4000 to $20,000 or more depending on its complexity.  Furthermore, the filing fee for a utility model patent is usually less than half that required for an invention patent.  On top of that, once an invention patent application is filed, the prosecution stage (i.e., the legal wrangling with an examiner at the Patent Office over the scope of the claims during the substantive examination of the application) can cost thousands of dollars.  In contrast, there is no substantive examination during the prosecution stage of a utility model patent since a utility model patent application is only examined for formalities.  (It is only when legal enforcement of a utility model patent is attempted that it is substantively examined.)  And furthermore, utility model patents generally require no maintenance fees, whereas invention patents commonly require maintenance fees over the lifetime of the patent that can add up to thousands of dollars.
 

The preparation of utility model patent applications is considerably less expensive than the preparation of invention patent applications because the level of unobviousness required for a utility model patent to be enforceable is much lower than for an invention patent.  Thus, utility model patents are said to be for incremental inventions.  Utility model patents are therefore usually only a few pages in length, whereas invention patents are usually at least a dozen pages long and commonly much longer. 
 

Of course, there are disadvantages to utility model patents which might warrant the additional cost of acquiring invention patents.  In most countries, utility model patents have a lifetime of only 10 years while invention patents have a lifetime of 20 years.  Utility model patents can only protect apparatuses, while invention patents can protect apparatuses and/or processes.  And monetary rewards available for infringement of utility model patents are generally less than what is available for infringement of invention patents.
 

In summary, it often makes sense to acquire protection in some countries using utility model patents and in some countries using invention patents.  Finding the optimum balance of strength of protection and cost can be a complicated strategic equation.  Consult with patent counsel to find the solution best for you.