Patent disclosure
Also called disclosure requirement, sufficiency of disclosure, enabling disclosure, written description requirement, enablement requirement
Patent disclosure is the information about an invention that an application must set out for the public in return for exclusive patent rights. In most jurisdictions the requirement includes support (written description), enablement and clarity, and in some countries a best mode1.
The tests are set by national or regional law: 35 U.S.C. 112(a) in the US2, Article 83 EPC at the EPO7 and Article 26 of the Patent Law in China10. It is a different thing from an invention disclosure, the internal form on which researchers or engineers describe in brief a potentially patentable invention1.
What the disclosure requirement is for
WIPO explains the requirement as a trade: in return for exclusive patent rights, patent holders must sufficiently disclose information about the invention to the public1. It lets third parties learn about new inventions without reinventing them, ensures rights are not extended to something withheld from the public, and communicates the scope of protection defined by the claims1.
- Support or written description. The description and drawings must give a basis for the claims. In the US the specification must describe the claimed invention in enough detail that a skilled person would reasonably conclude the inventor had possession of it at filing1.
- Enablement. The application must disclose the invention clearly and completely enough that a person skilled in the art can make and use the claimed invention1. If the claims become broader, more extensive disclosure may be necessary1.
- Clarity. The claims must be clear and concise, so third parties can tell what is and is not covered1.
- Best mode. In some countries at least one mode of carrying out the invention must be disclosed. In others, including the US, the best mode contemplated by the inventor must be disclosed1.
The test in the US, Europe and China
United States
- The specification must contain a written description of the invention and of the manner and process of making and using it, in full, clear, concise and exact terms enabling any person skilled in the art to make and use it, and must set forth the best mode contemplated by the inventor or joint inventor (35 U.S.C. 112(a))2.
- The MPEP describes the written description requirement as serving to demonstrate that the inventor was in possession of the claimed invention, and as separate and distinct from enablement (MPEP 2163)3.
- The enablement test asks whether the claimed invention is enabled so that any person skilled in the art can make and use it without undue experimentation (MPEP 2164.01)4.
- In Amgen v. Sanofi (2023) the Supreme Court said the specification must enable the full scope of the invention as defined by its claims6.
- Failure to comply with a requirement of section 112 is a ground of invalidity, except that failure to disclose the best mode is not a basis on which a claim may be canceled or held invalid (35 U.S.C. 282(b)(3)(A))5.
Europe
- The application must disclose the invention in a manner sufficiently clear and complete for it to be carried out by a person skilled in the art (Article 83 EPC)7.
- A detailed description of at least one way of carrying out the invention must be given, and the description must disclose any feature essential for carrying it out (Guidelines F-III, 1)8.
- Where the claims cover a broad field, the application is not usually regarded as satisfying Article 83 unless the description gives a number of examples or describes alternative embodiments or variations extending over the area protected by the claims8.
- If the disclosure is seriously insufficient, the deficiency cannot subsequently be remedied by adding further examples or features without offending Article 123(2) EPC9.
- Insufficient disclosure is a ground of opposition (Article 100(b) EPC)11. It is also one of the limited grounds on which a European patent may be revoked with effect for a Contracting State (Article 138(1)(b) EPC)12.
China
- The description must contain a clear and comprehensive description of the invention or utility model so as to enable a person skilled in the relevant field of technology to carry it out, with drawings where necessary (Patent Law, Article 26)10.
- The claims must be based on the description and define the scope of protection sought in a clear and concise manner (Article 26)10.
- An amendment to the application documents for an invention or utility model may not go beyond the scope of disclosure contained in the original description and claims (Article 33)10.
- These references are to the Patent Law as amended by the decision that took effect on 1 June 202110.
The three tests side by side
| United States | Europe (EPO) | China | |
|---|---|---|---|
| Provision | 35 U.S.C. 112(a)2 | Article 83 EPC7 | Patent Law, Article 2610 |
| Standard for sufficiency | Enable any person skilled in the art to make and use the invention2 | Sufficiently clear and complete for it to be carried out by a person skilled in the art7 | Clear and comprehensive, so as to enable a person skilled in the relevant field to carry it out10 |
| Adding to the disclosure after filing | No amendment may introduce new matter into the disclosure of the invention (35 U.S.C. 132(a))13 | A seriously insufficient disclosure cannot be remedied by adding examples or features (Article 123(2))9 | Amendments may not go beyond the scope of disclosure in the original description and claims (Article 33)10 |
Seen in the record
The US Supreme Court applied the enablement requirement of 35 U.S.C. 112(a) to claims covering a whole class of antibodies defined by their function6.
Amgen Inc. v. Sanofi
Amgen identified the amino acid sequences of 26 antibodies and described two methods for making others, but claimed the entire genus of antibodies that bind specified residues on PCSK9 and block it from binding LDL receptors. The Court held that the courts below correctly concluded the claims were not enabled, and affirmed6.
Draft and prosecute
Patent Drafting AI Agent
An AI agent that drafts claims and a full specification from a disclosure, with a compliance review before you finish.
Start draftingQuestions people ask
What is the difference between written description and enablement?
In the US they are separate requirements. Written description serves to show the inventor was in possession of the claimed invention3, while enablement asks whether a person skilled in the art can make and use it without undue experimentation4. The MPEP states that the written description requirement is separate and distinct from enablement3.
Does the US require the best mode to be disclosed?
Yes, 35 U.S.C. 112(a) requires the specification to set forth the best mode contemplated by the inventor2. However, failure to disclose the best mode is not a basis on which any claim may be canceled or held invalid5.
Can an insufficient disclosure be fixed after filing?
Generally not. At the EPO, a seriously insufficient disclosure cannot be remedied by adding further examples or features without offending Article 123(2) EPC9. In China, amendments may not go beyond the scope of disclosure in the original description and claims10. WIPO makes the same point: new subject matter cannot be added to the disclosure as of the filing date1. In the US, new matter can only be filed in a new application, such as a continuation-in-part, and claims relying on it get only the new application's filing date14.
How it connects
Go from the term to the task
Read how the method works, run it on your own product or idea, then try a free tool.
- 01 / How-toPatentability search: a practical guideCheck whether an invention is new before you spend on a filing.Read
- 02 / AI agentNovelty Search AI AgentAn AI agent that searches prior art for your invention and compares each reference with it feature by feature.Run it
- 03 / Free toolPatent draft style studioRewrite a technical description in claim language.Try tool