Clearance Opinion

A clearance opinion (also referred to as a freedom-to-operate opinion) is an opinion as to whether a product or activity will infringe any valid and enforceable patents.  Clearance opinions are territorial.  An opinion covering US patents does not cover activities outside the US.  Since laws in various countries differ, a clearance opinion should be obtained in every country where such an opinion is desired (e.g., where a product is made, used or sold).

Product clearance opinions should be obtained during product development and prior to tooling up for manufacturing a product.  In this way, the opinion can be relied upon for making decisions during product development to “design around” potentially infringed patents and before investing costly time and resources in tooling up for product manufacturing. 

A clearance opinion is based on the results of a clearance search (see Patent Research page).  A good clearance search will consider all of the patents in the most relevant field of art, which includes a review of all patents in the most relevant classes and sub-classes.  This is referred to as a classification search.  In the United States, patent classes and sub-classes are indexed in the US Patent Classification (USPC) System.

A good keyword search should be used to find relevant patents that may not readily turn up in a classification search.  A good keyword search considers relevant terms, analogous terms, and possible misspellings, and may limit the results of the search to a finite number of classes and sub-classes that are relevant to the product to yield a manageable number of patents to consider.  However, a keyword search should not be a substitute for the classification search, as every patent in the most relevant field of art should be carefully considered to ensure that no relevant patent is hastily overlooked.

It should be noted that expired patents are no longer enforceable, so they cannot be infringed.  As a consequence, care should be taken to eliminate any patents (from consideration in a clearance opinion) that are expired and unenforceable.

The term of a patent is typically 20 years from its effective filing date (i.e., the actual filing date or priority date), barring any patent term adjustment.  Expired patents can generally be eliminated by limiting the clearance search results to patents dating back to a given effective filing date (e.g., within the past 20-25 years).

It should be noted that inventions disclosed in expired patents are in the public domain (i.e., the patent rights have expired).  As a consequence, expired patents may be a valuable source of information for use when developing products to “design around” valid and enforceable patent claims (valid patent claims cannot “read on” that which is disclosed in an expired patent).

A patent may become abandoned and unenforceable for failure to pay maintenance fees.  Hence, the maintenance fee status of each patent should be considered.  Those patents that have become abandoned for failure to pay the maintenance fees may be eliminated from consideration in the clearance opinion.  See the USPTO’s Patent Maintenance Fees webpage to determine whether a patent’s maintenance fees are current. 

Unlike a patentability opinion, which considers that which is disclosed in existing patent documents, a clearance opinion considers what is claimed in current and enforceable patent documents.  That is, the results of the clearance search are studied to determine whether any claims are infringed.  In order for a product to be clear of infringement, all patent claims of every patent have to be clear of infringement.

A clearance study generally begins with an analysis of independent claims (i.e., claims that do not refer to any other claims).  If an independent claim is not infringed, no claim dependent therefrom should be infringed.

Even if a claim is not literally infringed, a risk infringement may remain present under a judicial doctrine referred to as the Doctrine of Equivalents.  Generally speaking, a product may infringe a claim under the Doctrine of Equivalents if the difference in a product feature and a claim limitation is insubstantial.

If there is a risk that a claim may be infringed, that claim has to be either invalidated or avoided by designing the product around the claim.

The demand for clearance opinions varies.  Some clients launch products without any opinions and others do not launch any products unless a written opinion is on file. 

Keep in mind that a clearance opinion is at best just that, an “opinion.” Opinions may differ among legal counsel.  So, an opinion is no guarantee that a product will be free from a charge of patent infringement.  In other words, a well-informed court may find that a product infringes, even if a well-reasoned product clearance opinion is obtained.

A clearance opinion may be viewed as a snapshot in time.  That is to say, a clearance opinion is limited to an analysis of patents (and sometimes published applications) preceding the opinion date.  It does not pertain to patents that issue after the opinion is provided.  It often includes a disclaimer about its scope and the extent of the counsel’s liability.  And, it will often state that it may not include all relevant patents or the most relevant patents.  At one time, opinions were important in asserting a position against willful infringement to avoid treble damages.  However, an opinion is no longer necessary to support this position. 

As a final note, if an opinion is desired, it has to be reliable and timely presented, and care should be taken not to circulate the opinion through channels that would compromise the attorney-client privilege.

Opinions are costly.  The typical charge for a non-infringement opinion for a single patent is about $10,000 USD.  Opinions can cost much more.  However, with the cost of litigation climbing, and a typical cost of litigation exceeding $1 million USD, the prevention of a single lawsuit may justify the cost of many opinions.

If you have a question about clearance opinions, askme at