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Learn more about prior art search, its various use cases, and why it should form part of your IP strategy.

prior art search

What is a prior art search?

A prior art search is a process that involves searching for and examining existing publicly available information to determine if an invention is novel and non-obvious.

The goal of a prior art search is to uncover relevant technology disclosures that predate an invention, or in the context of patents, the effective filing date of the claimed invention. 

Prior art is important in determining the patentability of an inventionvalidity of a patent, and can potentially impact the ability of a business to bring its products and services to market.

What is considered as prior art?

The term “prior art” refers to any publicly available information, which includes patents, patent applications, scientific literature, technical publications, product manuals, and other technology disclosures that describe similar or related inventions or technologies.

In the United States, the legal definition of prior art is set out in 35 U.S.C. § 102, which defines prior art as public disclosures that are “patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.”

Why conduct a prior art search?

In the different stages of the innovation cycle, a prior art search may be conducted to serve various purposes:

  • Assess novelty and non-obviousness of an invention
  • Guide R&D direction
  • Invalidate the claims of an asserted or blocking patent
  • Evaluate the strength and enforceability of a patent before licensing or investing
  • Determine if a product or service infringes on existing patents in a given jurisdiction
  • Gain insights regarding the existing technologies and patented inventions within a technology area

What are the types of prior art search?

Types of prior art search.png

Depending on the specific objectives, prior art searches can be categorized into four distinct types, each serving a different purpose:

  1. Patent Invalidity Search
  2. Patentability Search
  3. Freedom to Operate Search
  4. State of the Art Search


Patent Invalidity Search

patent validity or patent invalidity search is conducted to assess the validity and therefore, the enforceability of an existing patent. One of most common reasons for conducting this type of prior art search is in aid of patent litigation or in the event of a patent infringement suit.

Patent Litigation and Post Grant Proceedings

In a patent infringement suit, a defendant may choose to declare non-infringement. Another course of action is to  invalidate the claims of the asserted patent. In order to invalidate the claims of a patent, there must be evidence of prior art.

Apart from patent litigation in federal courts, the defendant may opt to use the patent invalidation mechanisms provided by the USPTO such as the inter partes review and post grant review, among others. These post grant proceedings are held before the Patent Trial and Appeal Board (PTAB) and may offer a faster and cheaper resolution compared to costly patent litigation.

Regardless of where a defendant chooses to litigate, there must be a thorough prior art or patent invalidity search conducted to prove that there is prior art.

Patent Licensing and IP Strategy

A comprehensive patent validity search is a crucial component of of a well-informed IP strategy.

  • Before acquiring or licensing a patent, the buyer or licensee must make sure that the patent claims are indeed valid in view of the prior art to avoid potential legal risks
  • As a risk management tool, a prior art search can assess the strength of a patent. Can it withstand patent challenges before the courts and other proceedings? This is an important step before a patent holder decides to enforce their patent and engage in patent litigation.

Patentability Search

patentability search, also known as a novelty search, is conducted to identify any prior inventions, publications, or other publicly available information that may be relevant to the invention.

Though this type of search is not a predictor for patentability, it can help a patent attorney evaluate the likelihood of obtaining a patent and provide a patentability opinion. This type of search aims to identify prior art that could potentially hinder the grant of a patent due to lack of novelty or non-obviousness.

A patentability search is a complete must before filing a patent application. It offers valuable insights to strengthen the drafting of the patent application, provide ideas for design-around, etc. It is ideal to conduct this type of prior art search even at the early stages of ideation, allowing for a more informed decision regarding R&D direction.

Freedom to Operate Search

freedom to operate (FTO) search, also called a “clearance search” is conducted before introducing a new product or service to the market. This search identifies existing patents and other intellectual property rights that may potentially be infringed by the new product or service. 

As patent rights are territorial, this type of prior art search is important before entering a new region or market. 

The main focus of this prior art search is to determine if there are existing patents in a given jurisdiction that disclose the same elements as the new product or service. 

A freedom to operate search will be the basis for a freedom to operate opinion that will be provided by a patent attorney.

State of the Art Search

State of the Art (SOA) search, also called a Collection search, is conducted to assess the existing technical advancements in a particular field. It identifies prior art relating to a certain technology which provides insights regarding the patentability of an invention, infringement risks, evaluation of the inventive step, among others.

This wider scope of a prior art search not only identifies technologies that are similar to your idea or invention, but also “competing art” which are technologies that solve the same problem but in a different way. 

How do I conduct a prior art search?

Here’s a basic framework for conducting a prior art search.
  1.  Define the invention and set the scope.
    Every prior art search starts with a thorough understanding of the essential features or the “inventive concept” of the subject matter or claimed invention. Define the “effective filing date” of the invention. This forms the basis of your search criteria.
  2. Identify keywords and classifications.
    Build a list of keywords and keyword strings associated with the invention. Apart from text searching, patent classification codes (CPC or IPC) can improve the precision of the search and narrow down your pool of results.
  3. Use search databases.
    Utilize reputable, publicly available patent databases such as Google PatentsEspacenet and the USPTO. For non-patent literature searching, include academic journals, and conference proceedings etc.
  4. Optimize and analyze results.
    A prior art search is an iterative process, and requires continuous optimization. Refine search queries based on your initial results. Combine various search strategies, e.g. keywords search + CPC.
  5. Keep detailed records of relevant references.
    A typical prior art search report will include a claims mapping or technical mapping chart which maps the claims of a patent or the elements of an invention to the references found. Download a sample report here.
  6. Get a patent search provider.
    As a comprehensive prior art search can be a daunting task, enlisting the help of patent research professionals can also be beneficial. Find a research partner that understands both the legal and technical aspects of a prior art search, and has a proven track record in providing quality results.
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