What is a statutory disclaimer of patent claims?

A statutory disclaimer of patent claims is a formal, permanent filing by which a patentee voluntarily gives up the right to enforce one or more specific claims of an issued patent. The governing authority is 35 U.S.C. § 253(a), which permits a patentee, whether of the whole or any sectional interest in the patent, to disclaim any complete claim by making a written declaration at the Patent and Trademark Office.

The two functions of 35 U.S.C. § 253(a)

Section 253(a) does two distinct things in a single provision.

First, it codifies a claim severability principle. The opening sentence establishes that whenever a claim of a patent is invalid, the remaining claims shall not thereby be rendered invalid. This protects a patent owner from losing the entire patent because one claim turns out to be defective.

Second, it provides the voluntary disclaimer mechanism. The patentee may disclaim specific claims by filing a written statement. Once recorded at the USPTO, the disclaimer is considered part of the original patent to the extent of the interest of the disclaimant and those claiming under him.

These two functions are complementary: the severability principle ensures that weak or disclaimed claims do not pull down the remaining claims, and the disclaimer mechanism gives the patent owner a clean procedural path to relinquish claims it no longer needs or cannot defend.

When and why patent owners file a statutory disclaimer

The statutory disclaimer mechanism under 37 CFR § 1.321(a) is a tool for patentees of issued patents. An applicant who wants to drop a claim before the patent is granted does so by canceling it through an amendment to the pending application; the statutory disclaimer is a post-grant filing.

Patent owners typically file a statutory disclaimer in one of two circumstances:

• After an invalidity finding. A court, the Patent Trial and Appeal Board, or another post-grant review body has found specific claims invalid. The owner disclaims those claims to narrow the patent to its defensible scope and to reduce ongoing litigation exposure.
• Proactively. The patent owner concludes on its own that certain claims are too broad or otherwise likely invalid and disclaims them to limit risk before a challenge arises.

What can be disclaimed

A statutory disclaimer must cover complete claims. There is no mechanism to disclaim part of a claim or to use the disclaimer to narrow or modify claim language. A statutory disclaimer is not a vehicle for adding or amending claims, because neither the statute nor the rules provide authority for doing so.

A patent owner who wants to narrow an existing claim rather than eliminate it must use a different procedure. Reissue allows claims to be amended or replaced. Reexamination allows claims to be narrowed or canceled in response to a prior art challenge. The statutory disclaimer does neither of those things: it removes specific claims from the enforceability of the patent, nothing more.

Formal requirements

Under 37 CFR § 1.321(a), a valid statutory disclaimer must:

• Be signed by the patentee or an attorney or agent of record.
• Identify the patent and the specific complete claim or claims being disclaimed.
• State the present extent of the patentee's ownership interest in the patent.
• Be accompanied by the required fee under 37 CFR § 1.20(d).

After the disclaimer is recorded, a notice is published in the Official Gazette and attached to the printed copies of the patent specification, making the disclaimer part of the accessible public record.

Effect of the disclaimer

Once recorded, the disclaimer is thereafter considered part of the original patent to the extent of the interest possessed by the disclaimant and by those claiming under the patent, such as successors and assigns. The patent owner can no longer enforce the disclaimed claims against anyone.

Two limitations on the scope of the disclaimer matter in practice:

The disclaimer is limited to the disclaimant's interest. The statute provides that the disclaimer takes effect "to the extent of the interest possessed by the disclaimant and by those claiming under him." A patent owner's disclaimer does not necessarily relinquish the rights of the public or a third party. A disclaimer filed after an adversarial proceeding, for example, does not automatically undo prior judgments that were entered on the basis of those claims.

Remaining claims are unaffected. Because of the severability principle in § 253(a), disclaimed claims do not bring down the remaining claims of the patent. The patent continues in force on its surviving claims with no change to their scope.

Statutory disclaimer vs. terminal disclaimer

Both mechanisms appear in 35 U.S.C. § 253, but they address completely different objects.

Under 35 U.S.C. § 253(b), a patentee or applicant may disclaim or dedicate to the public the entire term, or any terminal part of the term, of the patent granted or to be granted. Terminal disclaimers under 37 CFR § 1.321(c) are filed primarily to address judicially created double patenting rejections, where the concern is unjustified extension of the patent term, not the validity of specific claims.

The practical rule: when the question is "which claims should this patent have," the statutory claim disclaimer is the tool. When the question is "how long should this patent run," the terminal disclaimer is the tool.

Choosing between a statutory disclaimer and other post-grant tools

For practitioners managing a post-grant portfolio, the statutory disclaimer is the fastest path to shedding claims the owner cannot or will not defend. It does not require a full prosecution proceeding, but it also cannot do what prosecution can do. Once filed, the loss of those claims is permanent.