Patent Invalidation Search | How to Challenge a Patent’s Claims?

4. Date Criteria in Invalidation Search: Understanding the Role of Timing

In a patent invalidation search, timing plays a critical role in determining whether a patent’s claims are valid or should be invalidated. The date criteria refer to the specific points in time that must be considered during the search, particularly the priority date and the filing date of the patent.

Understanding these date-related factors is essential for determining whether prior art can be used to challenge a patent’s validity. Here’s a breakdown of the date criteria involved in an invalidation search:

4.1. Priority Date

• Definition: The priority date is the earliest date on which an invention is considered to have been disclosed or filed. It marks the starting point for determining novelty and obviousness. Any prior art published or disclosed after this date cannot be used to invalidate the patent.
  
  
• How It Works: The priority date is typically the filing date of the patent application, but it can also be earlier if the applicant claims priority from an earlier filing in another jurisdiction (e.g., through the Paris Convention or a PCT application). This means that prior art that was published or publicly disclosed before this priority date must be considered when evaluating the novelty and non-obviousness of the claimed invention.
  
  
• Determining the Priority Date: To accurately conduct an invalidation search, it is crucial to identify the priority date for the patent in question. This ensures that only prior art published or disclosed before this date is considered, while information released afterward is excluded from the analysis.

4.2. Filing Date

• Definition: The filing date of a patent is the official date on which the patent application is submitted to the relevant patent office. This is the key date used to establish the timeline for prior art searches.
  
  Filing Date vs. Priority Date: If the priority date is different from the filing date, the filing date is used in jurisdictions where no priority claim is made, or where the application is the first disclosure. The filing date becomes particularly important if the applicant is not claiming priority from an earlier patent application. In cases where priority claims are made, the earlier date (priority date) takes precedence.
  
  Effect on Invalidation Search: The filing date determines which pieces of prior art are relevant to the invalidation search. If prior art exists that was published before the filing date, it is considered valid for challenging the patent’s claims. Prior art released after the filing date is generally disregarded.

4.3. Grace Period

• Definition: Some jurisdictions provide a grace period, which allows the inventor to publicly disclose their invention before filing the patent application without the disclosure being used against them as prior art. This period typically lasts up to one year before the filing date, depending on the jurisdiction.
  
  
• How It Affects Invalidation: If the inventor discloses the invention publicly during the grace period, that disclosure will not be counted as prior art against the patent application. However, if the patent is challenged after issuance, the grace period may be used to determine whether the invention was publicly disclosed before the filing date. An invalidation search must account for any public disclosures made during the grace period to ensure accurate timing for prior art considerations.
  
  
• Jurisdictional Variations: Different jurisdictions have varying rules regarding grace periods. For example, in the United States, the one-year grace period applies only to the applicant’s own disclosures, whereas in other countries (like Europe), any public disclosure before filing may count as prior art, regardless of the grace period.

4.4. Publication Date of Prior Art

• Definition: Prior art is only relevant if it was publicly disclosed before the priority or filing date of the patent. The publication date of prior art (patent publications, articles, patents, conference proceedings, etc.) must be established to determine whether it could affect the patent’s validity.
  
  
• How It Works: In an invalidation search, the publication date of prior art must be carefully compared to the priority or filing date of the patent. If the prior art was published after the patent’s priority date, it is not considered relevant to invalidating the patent. Conversely, any publication that predates the priority date can be examined to assess its potential to invalidate the claims of the patent.
  
  
• Importance in Invalidity Assessment: Determining the publication date of prior art is one of the first steps in the invalidation search. It helps define the pool of relevant prior art that could challenge the patent’s validity. Ensuring that the search includes only those references published before the priority date is crucial for an accurate invalidation search.

4.5. Post-Grant and Opposition Periods

• Definition: In many jurisdictions, there is a post-grant period during which a granted patent can be challenged. This period is often accompanied by opposition procedures or post-grant review mechanisms that allow third parties to present evidence of prior art or other reasons to invalidate the patent.
  
  
• How It Affects Invalidation: In such cases, prior art and any relevant evidence that could invalidate the patent are reviewed during the post-grant period. For example, during an opposition procedure in the European Patent Office (EPO), prior art can be submitted to demonstrate that the patent should never have been granted. The timing of the post-grant review plays a role in determining the acceptable prior art, as the validity of a granted patent is reviewed based on documents available up until the time of the opposition filing.
  
  
• Considerations for Invalidity Searches: During this period, it is critical to review all prior art that could affect the patent’s validity, and searches should cover prior publications that were not initially considered or disclosed during the original examination process. This ensures that invalidity searches conducted after a grant or during opposition can effectively challenge the patent’s claims.

4.6. Prior Art vs. Public Use or Sale

• Public Use and Sale: In some jurisdictions, public use or sale of an invention before the patent filing date can invalidate the patent due to the invention being publicly disclosed. This includes instances where the invention was commercially available or used in public prior to filing the application.
  
  
• How It Works: If the invention was used or sold publicly before the filing date, it can be considered prior art. Invalidating a patent on these grounds requires a precise understanding of the timeline of when the product or idea was first used, sold, or otherwise made publicly available.
  
  
• Considerations for Invalidation Search: It is essential for the invalidation search to include evidence of public use or sale prior to the filing date. This might involve combing through online databases, product catalogs, sales records, and other public disclosures.