Public Prior Use: A Comprehensive Introduction
1. Introduction
In patent law, the concept of “public prior use” plays a crucial role when assessing whether an invention is novel. An invention is considered new only if it was not accessible to the public before the priority date. Public prior use refers to a situation where the technical teaching was already available to the public prior to the filing date, effectively becoming part of the prior art. As a result, a patent or utility model may be refused, revoked, or invalidated because the invention is deemed not new.
In this article, you will learn about the legal framework governing public prior use, the conditions under which it is considered novelty-destroying, the methods and tools used to prove it, and the role of various types of evidence, including witnesses. You will also find practical tips to help you navigate this issue in a corporate environment.
2. Legal Framework and Basics
Novelty is a core requirement for patent protection. Both the German Patent Act (§ 3 PatG) and the European Patent Convention (Article 54 EPC) stipulate that an invention must not be made available to the public prior to its filing (or priority) date. The state of the art includes anything publicly disclosed—whether in writing, orally, through use, or in any other form. Public prior use describes a scenario in which a product, process, or technical solution was openly accessible before the relevant date. Even a single instance of use or a single offer can suffice to destroy novelty.
3. Requirements for Public Prior Use
To establish public prior use, the following conditions must be met:
- Public Accessibility: The technical teaching must have been presented in such a way that an unlimited number of persons could potentially obtain knowledge of it.
- Identifiable Technical Features: Skilled persons should be able to identify the technical aspects without inventive effort, for example by examining, disassembling, or testing a readily available product.
- Occurrence Before the Priority Date: The public use must have taken place before the filing or priority date of the patent or utility model in question.
4. Proving Public Prior Use
Demonstrating public prior use can be challenging. The standard of proof is high, and you must provide conclusive evidence showing who revealed what, when, and to whom. A seamless chain of evidence is essential:
- Who? Who made the invention accessible?
- What? What specific technical feature or product was disclosed?
- When? On what date did the disclosure occur?
- To Whom? Was the invention accessible to an indefinite group of people?
- Where? Where was the disclosure?
If any element of this evidence chain is missing or questionable, the argument for public prior use may fail.
5. Types of Evidence in Detail
Various types of evidence can be used to prove public prior use:
- Documentary Evidence: Invoices, delivery notes, catalogs, and other records that confirm the timing and nature of the disclosure.
- Witness Testimony: Individuals who can credibly attest to having knowledge of the technical teaching or who witnessed its public availability.
- Expert Opinions: Technical experts who can clarify complex relationships and confirm what a skilled person would recognize.
- Inspection (Augenschein): Direct examination of a product or system, potentially involving disassembly to reveal relevant technical features.
- Statutory Declarations (Affidavits, sometimes not evidence): Official statements confirming the authenticity of documents or the source of evidence.
In proceedings before the European Patent Office (EPO), similar evidence options are available under Article 117 EPC.
6. Special Considerations for Utility Models
For German utility models, the definition of prior art is more limited, only including domestic disclosures (written or through public use within Germany). Foreign public uses are irrelevant for utility model novelty. Also, oral disclosures do not count. Strategically, it may be wise to file a parallel utility model alongside a patent application. This can serve as an additional protective measure if a prior use occurred abroad, making it easier to assert rights later.
7. Witness Testimony – Opportunities and Risks
While a witness can fill gaps in your evidence, relying on witness testimony has its downsides:
- Cross-Examination: Under questioning, a nervous or poorly prepared witness may appear less credible.
- Unavailable Witnesses: Illness or job changes can mean a crucial witness is no longer available.
- Credibility Issues: A CEO or someone with a direct stake in the outcome may raise doubts about impartiality.
Avoid influencing witnesses beforehand and consider naming more than one witness. Use statutory declarations primarily to confirm the authenticity and origin of documents, rather than providing the entire narrative. This approach preserves the possibility of calling a witness later if needed.
8. Practical Recommendations
To build a solid chain of evidence, it is advisable to adopt a clear strategy early on:
- Optimize Documentation: Ensure careful archiving of invoices, delivery notes, and catalogs.
- Coordinate Internal Departments: Involve purchasing, R&D, sales, and quality management teams.
- Maintain a Clear “Red Thread”: Make sure product numbers, item codes, and references match across all documents.
- Leverage Catalogs and Timestamps: Old product catalogs with dates or acceptance protocols for software-controlled systems are valuable.
- Handle Supplier Parts and Third-Party Products Wisely: Check if retained samples exist or consider cooperating with the original manufacturer.
- Select Witnesses Prudently: Choose impartial individuals and avoid conflicts of interest.
9. Conclusion and Outlook
Public prior use can be a potent factor in patent and utility model cases. Thorough and credible evidence documentation is key. Invest time upfront to gather all relevant documents and confirm that the technical teaching was indeed accessible to skilled persons. With careful preparation, you can minimize risks and improve your chances of success in examination, opposition, appeal, revocation, or infringement proceedings.
10. Further Information
- German Patent Act (PatG) and European Patent Convention (EPC)
- Commentaries and legal literature on PatG and EPC
- Case law databases and legal resources for precedent research
- Consultation with patent attorneys or IP experts
Armed with this understanding, you are now better equipped to judge whether an invention was genuinely new or if public prior use had already paved the way, making the claimed invention an “old acquaintance” in the state of the art.
