MPEP 1400

Correction of Patents (MPEP 1400)

by patentbar on December 8, 2007 · 10 comments

in MPEP 1400

Chapter 1400: Fixing Mistakes in Already Issued Patents: (See 35 U.S.C. 251)

Certificates of Correction

A certificate of correction is a mechanism to correct minor, non-substantive inconsistencies between the application as prosecuted and the patent ultimately issued (clerical corrections). A certificate of correction cannot be used to add new matter or for patents that require substantive reexamination.

Who can request a certificate of correction?

  • If mistake is by the PTO: Commissioner acting sua sponte – on his own accord; Commissioner acting on information provided by 3rd party; or the patentee or assignee – no fee required.
  • If mistake was applicant’s fault: the patentee or assignee may request so long as error was made in good faith; fee required.
  • 3rd Party – PTO has no duty to act upon or respond to 3rd party request for a certificate of correction; patentee is given opportunity to respond; 3rd party papers will not be entered into file wrapper.

What type of errors are correctable via a certificate of correction?

  • Minor Errors – grammatical and typos in spec or drawings; if PTO’s mistake, they have discretion not to issue certificate of correction and instead, may place request in file for public notice purposes
  • Errors that Affect Understanding or Interpretation – misspelled words, error in name, missing text, wrong formula or equation
  • Serious Errors (rare) – PTO may issue a corrected patent

Certificate of correction procedure –

Applicant’s or PTO’s mistake – request made to certificate of correction branch of PTO; identify patent number and issue date; identify how errors occurred; include fee if not PTO’s fault (no small entity discount); identify action requested (certificate of correction, corrected patent, letter in file); use of PTO form is encouraged

Special certificate of correction procedures –

  • Rule 324 Petition to Correct Inventorship Errors: requires statement from each inventor being added that error occurred without deceptive intent on their part; statement from each inventor named (including those being deleted) agreeing to change; statement by all assignees agreeing to change; and fee
  • court order can also change Inventorship
  • Assignee Name Correction: Rule 183 Petition with fee; statement that failure to include was inadvertent; request that R3.81(a) be waived; and copy of Notice of Recordation of Assignment
  • Priority-Related Errors – certificate of correction is proper to correct, only if: 1) domestic or foreign priority properly claimed but not printed on face of patent; 2) foreign priority perfected in a (non-design) parent application but not claimed in patented continuing application; 3) 119(e)/120 domestic priority not claimed in app filed before 11/29/00 , but co-pending app to be added by certificate of correction is identified in app papers; or 4) 120 domestic priority not claimed in app filed on or after 11/29/00, but co-pending app to be added by certificate of correction is identified in application papers (requires R78(a)(3) – unintentional delay – and surcharge

Legal effect of a certificate of correction –

Retroactive – becomes part of patent, and dates back to original issue date


What is a disclaimer?

A disclaimer is a mechanism for any (full or partial) owner of a patent to disclaim “too much” patent protection originally received. Two Types:

  • Statutory – patentee give up subject matter by disclaiming one or more claims of patent
  • Terminal – patentee gives up a portion of the entire patent’s term

Why use a disclaimer?

  • patentee discovers one or more claims are invalid (e.g., too broad) or defective and desires to delete such claims form the issued patent
  • must be without deceptive intent (i.e., discovery must be subsequent to patent’s issuance)
  • patentee desires to dedicated one or more complete claims to the public;
  • disclaimer is irrevocable and binding on the patentee/assignee’s successors in interest
  • each joint inventor can only disclaim his percentage of the patent

Patent Disclaimer Procedure –

  • Addressed to correction of patents branch of PTO
  • Identify Patent Number
  • Identify claims or term to be disclaimed
  • Identify disclaimant and their ownership interest in the patent
  • Include R20(d) Fee – small entity discount applies
  • Signature by patentee/assignee or attorney
  • Disclaimer is placed in file, attached to patent, and listed in OG
  • Terminal Disclaimer filed in an application is revocable until patent issues
  • Terminal Disclaimer filed in an application does not carry over to continuations (unless it says so), but it does carry over to CPAs and RCEs


What is Reissue?

Reissue is a mechanism for correction of scope and contents of patent, which requires substantive examination. “The specification and claims of a patent, particularly if the invention be at all complicated, constitute one of the most difficult legal instruments to draw with accuracy.” A reissue patent offers to surrender original patent, at which point you file an amended application for the unexpired term of the original patent.

Grounds for Reissue –

  • In order to broaden claims, must file for reissue within two years from the issue date of original patent
  • Cannot introduce any new matter
  • error in specification or claims, which occurred without deceptive intent, that renders patent wholly or partially inoperative or invalid
  • Commissioner may issue one or more patents based on reissue app (can file RCE, continuation and divisional apps off a reissue, but no CIP)

What Errors Can Reissue Correct?

  • any inaccuracy or error which could have been corrected by amendment during prosecution or by filing a continuation in the original app
  • can also correct errors normally done by certificates of correction or Disclaimer only if incidental to Reissue process
  • can conform drawings to spec and vice versa – this is not new matter
  • can cure inadvertent failure to claim a statutory class of invention
  • can cure errors in Inventorship not curable by certificates of correction (e.g., lack of consent or all parties do not agree)
  • can cure errors in priority not curable by certificates of correction, but if patent issued from an application filed on or after 11/29/00: cannot cure failure to claim 119(e) priority (to provisional); and to cure foreign or 120 domestic priority in non-design patent requires a R78(a)(3) petition and the R17(t) surcharge
  • cannot cure R56 or 112P1 (best mode) violations, or totally defective oath

Types of Reissue –

Broadening – when patentee discovers claims are too narrow

  • new or different claims are sought that read on subject matter not read on by original claims;
  • new claims directed to different statutory class of invention;
  • even if some elements of a claim are narrowed, as long as any element is enlarged
  • must be disclosed and enabled in original app spec;
  • two year time limit to file reissue (not to present broader claims)
  • all parties (assignees and inventors) must agree
  • Recapture Doctrine – applicant cannot broaden claims in an attempt to reclaim subject matter given up by a narrowing amendment, argument or cancellation in original application

Narrowing – when patentee becomes aware of prior art

  • seeks to amend claims
  • may act like a disclaimer if any claims are eventually canceled

Same Scope

  • seeking to add claims of same scope is improper
  • may seek, however, to correct indefiniteness errors


  • patentee may seek to present new claims to provoke an interference (copying claims from another issued patent)

Reissue Application Filing Mechanics –

  • a copy of the patent spec (double column, single-sided sheet format), including the claims, and a clean copy of the drawings
  • a copy of any disclaimers, CoC, or reexamination certificates issued in the patent, and disclose any other proceedings in which patent is or was involved
  • may file an amendment either on a separate sheet of paper or by “cutting and pasting” copy of patent. (All [deletions] and additions in spec must be noted; All deletions and additions in text of amended claims must be noted; statement of which claims are cancelled, and separate sheet with status of all claims; and Amendments to drawings must be shown on separate sheet and noted in red with “amended” label. Added drawings must have the “new” label. Deleted drawings must be completely enclosed in brackets and “cancelled.”)
  • must include statement of offer to surrender original patent; the actual ribbon original; or state that it is “lost or inaccessible,” at filing
  • Oath stating: applicant believes patent is wholly or partially inoperative or invalid by reason of claiming more or less, or defective spec or drawings; error arose w/o deceptive intent; specifying at least one error; all info required by R63; AND all assignees consent or statement that there’s no assignee
  • must be signed by all assignees, if any unless seeking to enlarge the scope of claims in which all inventors must sign as well
  • small entity discounts apply

Prosecution of a Reissue Application –

  • Reissue app prosecution is identical to examination of “normal” apps, with one exception: file is open to public for inspection and comment
  • upon filing reissue app, notice is published in OG, file is publicly accessible and 3rd parties may file R291 protest (2 months from OG)
  • filing a reissue app: reopens prosecution as to all claims; allows prior art of record to be reapplied; and there is no presumption of validity
  • reissue apps are granted special status
  • duty of disclosure applies

Effects of a Reissue Patent –

Filing Date: given effective filing date of original app

Result: after reissue app process, patentee may end up with original, broadened, narrowed, or no patent at all

Issuance: when reissue patent issues, original patent is surrendered

Expiration: expires when original patent would have expired

Maintenance: fees based on original issue date and payable on same schedule

Infringement: no effect for reissue patent claims that are common, or substantially identical, to original patent claims

Intervening Rights For New Claims: between issue date of original patent and reissue patent, there is an absolute continued right to use or sell products manufactured before date of reissue and covered by new claims for those who actually relied on the original patent. Court may fashion equitable remedy for products manufactured after date of reissue if substantial preparation was made prior to reissue grant.

Correcting an issued Patent (part 1) (1400-1412.01)

Reissue Applications:

  1. These are filed to correct errors in the patent that was published. Examples:
    1. Claims were too narrow or too broad
    2. The disclosure had innacuracies
    3. Applicant failed to or incorrectly claimed foreign priority
    4. Applicant failed to or incorrectly made reference to a prior copending application (like in a CIP, Divisional, or CPA situation).
    5. HOWEVER: A reissue does not work if the patent does not properly claim priority over a prior PA (35 U.S.C. 119(e)). (If the later app was filed on or after 20001129)

1403: Time & Diligence:

  1. Usually if filed within 2 years of issue the Reissue request is not considered late or non-diligent due to delay.
  2. Prior to the 2 year limit, reissue apps that are seeking to broaden the scope of claims will not be rejected merely for not having been filed diligently (examiner will not reject on those grounds). After 2 years, reissue apps are not allowed to broaden claims (although other types of reissue apps could occur).

1405: Reissue and the Patent’s Term (Lifespan):

  1. 35 U.S.C. 251 says that the reissue just fills out the rest of the term of the original patent (like a built-in terminal disclaimer, a reissue is just to fix problems with the original patent, it can never extend the term of patent protection). For example: say we eliminate a claim to benefit from an earlier app that was shortening the term of the current app. This is still not extending the term of the app from its original length.

1410: What goes into a Reissue App:
(37 CFR 1.171, 1.173(a))

  1. A full copy of the original app in full must be included in double-column format. (Just retyping the spec is not enough, a true copy)
  2. A special reissue oath or declaration; it must comply with 37 CFR 1.163 (like normal) and additionally 37 CFR 1.175 (extra for this oath/decl).
  3. If the patent has been assigned, the reissue app must also have the consent of the assignee.
  4. How to actually amend the reissue app to correct errors:
    1. 1. Physically incorporate changes by cutting & pasting into the copy of the original (remember to use the underline and formatting used in other amendments as seen in 37 CFR 1.173(d)).
    2. 2. By providing a separate amendment paper along with the app.

1411/1412: Remember: NO NEW MATTER IN A REISSUE APP! Also, the reissue app must be for the same general invention. However, remember that the court will look at the original disclosure as a whole, so this means that the reissue could contain claims over subject matter that was not claimed in the original patent. As long as the original subject matter supports the new claim (with no need for new subject matter) then a new claim can be allowed in the reissue app too.

More on Reissue (Including when broadening claims is allowed) (1412-1450)

1412.02: Denying a Reissue when it tries to ‘recapture’ previously canceled Subject Matter.
When the original patent was granted because the applicant actually gave up subject matter (like narrowing claims, adding limitations) then later on a reissue app is not allowed to ‘recapture’ this material that was already surrendered.
There are 3 steps for this test:

  1. 1. Are the reissue claims actually broader than the original patent, and if so how are they broader? if yes:
  2. 2. Do the broadened claims actually relate to subject matter that was previously surrendered.
    1. Substep 1: Did the original app actually have surrendered material, this can come from amended claims, earlier rejection reasons, arguments the applicant made, anything in the record showing how the patent was narrowed.
    2. Substep 2: If there actually was surrendered material, do the broadened reissue claims actually rely on that material in order to meet the basic description/enablement/best mode & definiteness requirements of a claim?
  3. 3. Finally, if the claims were materially narrowed in other ways to avoid recapture they should not be denied, but if they were not narrowed enough, the reissue claims should be rejected.
    1. For example, a reissue claim cannot broaden scope of the claims back to what it was for a previously rejected & canceled claim that was tried in the original app. (No do-overs on trying to get broad claims)
    2. Also, look for omissions of limitations that were necessary for overcoming prior art. The reissue claims cannot omit limitations after the patent is granted if they were necessary the first time.

1412.03: Steps for rejecting recapture claims:

  1. 1. 35 U.S.C. 251: Remember: There is a 2 year limit from the original issue on the time to make a reissue app if it is going to broaden claims. However, reissue apps can be chained together as long as they are all broadening so: Original app + 18 month for 1st broadening reissue app + 18 months for 2nd broadening reissue app is allowable even though the final reissue app is > 2 years after the original issuance date.
  2. 2. Caveat on what ‘Broadening’ Means:
    1. A ‘broadened’ claim means that a claim is now broader than any claim in the original patent, so for example, a dependent claim that has been given a larger scope in the reissue is still not broadened because it must still have all the limitations of its parent independent claim (assuming the parent independent claim was not itself broadened too).
    2. Remember: A broadened claim must be greater than the scope of each & every claim in the original patent.

1412.04: Correcting the Inventorship via Reissue:

  1. While it is allowable to correct inventorship via reissue, it is preferable to simply use a certificate of correction to fix errors. (37 CFR 1.324). The certificate can be used if:
    1. 1. the only change to the patent is to correct inventorship; and
    2. 2. all parties agree and inventorship is not contested.
  2. However, if other changes need to be made or there is a contention over inventorship, reissue may work:
    1. Since changing inventorship is not broadening claims, the assignee of the entire patent may swear the oath/decl for this change.
    2. However, if the reissue will also change claims, then all the inventors need to sign.

1413: Drawings: (37 CFR 1.173)

  • Just as with the spec, a clean copy of all the original drawings must be included with the reissue app
  • For making amendments to the drawings for reissue:
    • you are not allowed to physically alter the original drawings at all.
    • Instead, if there is a need for a new drawing, it should be submitted on a replacement sheet (clearly labeled with figure numbers being updated). Each replacement must have ‘Amended’, ‘New’, or ‘Canceled’ at the bottom of the sheet (depending upon what is happening to the drawing in question).
    • Optionally, the applicant may also include annotated versions of the amended drawings.

1414: Content of Reissue Oath/Decl: (This is the extra material in 37 CFR 1.175 that is required in addition to the 1.63 oath/decl material).

  1. 1. A statement that the applicant believes the original patent to be wholly/partially invalid:
    1. because of defective spec/drawing OR
    2. because the claims are either > or <>
  2. 2. A statement of at least one error that is relied upon as a basis for reissue.
  3. 3. A statement that all errors being corrected occurred without deceptive intent by the applicant; and
  4. 4. All the information required in 37 CFR 1.63 (the normal oath material).

1415: Show me the $$ (fees):

  1. There are: filing, search, and examination fees for a reissue just as for a normal patent. Also, if the reissue app is > 100 pages or has too many claims, the excess size & claims fees apply too.
  2. Just as with a normal app, it is not necessary to pay the fees on the filing date, but if done > 20050701 there is a surcharge for paying these fees at a later date.
  3. The app size fee for reissue apps kicks in at > 100 sheets and an extra fee for each 50 sheets over that (rounded up).
  4. Claims: For patents after 20041208 the reissue app is treated as: all claims in original patent +- claims in the reissue. So if the final reissue will have > 3 independent claims, and/or > 20 dependent claims, then the 37 CFR 1.16(i) fees apply for excess claims.

1415.01: Maintenance fees on the original patent: The patentee must still pay maintenance on the original patent even if a reissue is pending. If the patentee has not paid these fees under 35 U.S.C. 41(b); 37 CFR 1.20, then the patentee is not allowed to file for reissue. (sort of like abandonment only after the patent is granted).

1416: In the old days the applicant had to actually give up the original ‘ribbon copy’ of the patent when seeking reissue, 37 CFR 1.178(a) says that is not necessary.

1417: Using a reissue to properly claim foreign priority (35 U.S.C. 119(a)-(d)):
EVEN IF THE CLAIM WAS PROPER IN THE ORIGINAL APP: The claim must be properly re-asserted in the reissue application as well.

When the claim for foreign priority is being perfected only in the reissue app (it’s new):

  1. As long as the claim is only being perfected (like a missing copy of the foreign filing is provided in the reissue) this is allowed. In this case, the original app tried to claim foreign priority, but was deficient, so perfecting the error in the reissue is allowed.

1418: Notification of other prior/concurrent proceedings: Under 37 CFR 1.178(b) the applicant must inform the USPTO about any previous or copending actions that relate to the patent, and what the outcome of previous actions was. Also, since the oath/decl of 37 CFR 1.63 is signed, the applicants have the same disclosure requirements as for a normal patent app.

1441: Reissue apps are given priority, but 2 month Delay Period: Reissues get treated as ‘special’ apps to speed up the reexamination. However, there is normally a 2 month delay from the date on which the reissue app is published to when examination begins. This is to allow the public to read & comment on the published reissue app.

1450: Restriction Requirements: Just as with a normal app, the examiner may require the applicant to elect a species if the new claims in a reissue app are claiming separate & distinct inventions. There can be divisionals that come out of reissue apps (see next lesson).

More on Reissue: Divisionals & RCEs from Reissue; Disclaimers; Certificates of correction (1451-1490)

1451: Divisional Reissue Apps (types of Continuation Apps where the reissue parent is copending):

  1. 1. These can be required by the examiner under 37 CFR 1.176(b) when new claims are directed at separate & distinct inventions. OR
  2. 2. The applicant can elect to make a divisional on his own under 37 CFR 1.177. Requirements:
    1. The original reissue app itself must contain a cross reference to divisionals in the first sentence of the app. (If it does not, the examiner will make an objection and require that the app be amended with the referecences).
  3. Other Continuation Reissue Apps (Like RCE’s)
    1. As long as the continuation complies with rules for reissue (like broadening claims, correcting errors, etc.) then it will be allowed

1452: Requesting an RCE inside of a Reissue: On or After 20000529 the applicant may request the RCE on any reissue that itself was filed on or afer 19950608.

1453: Amending Reissue Apps: (see 37 CFR 1.173(b)-(g); 37 CFR 1.121(i)):

  1. Format (watch out this is slightly different than other formats): When omitting, [put omitted material in brackets]; and new matter should be underlined.
  2. Why no strikethrough? Probably because the strikethroughs are preserved from the original patent? or some other reason?

Modifying the Spec:

  1. Use the markings seen above, except that entire paragraphs may be deleted by just making a statement that the paragraph is deleted.
  2. Any changes are between the amendments are compared to the original patent and not in comparison to earlier amendments to the reissue.

Modifying the Claims:

  • The entire text of each claim that is being modified must be made using the markings seen above.
  • Each new claim has to be presented in full and underlined
  • For canceling a claim (either in the reissue or original app), there should just be a directive to cancel the claim put into the claims, no need to delete it [via brackets] is required.
  • Original patent claims are never renumbered! (37 CFR 1.173) Even canceled claims retain their numbers, and any new claims for the reissue or amendment must come after the original patent claim numbers.

Modifying the Drawings:

  • Remember, drawings are not amended, instead replacement sheets that are clearly marked must be filed with clean copies of the new drawings in full (and note that old drawings on the same sheet that are not changed must be copied as well).


  1. 1. When changing an existing paragraph, remember: COPY THE WHOLE PARAGRAPH into the amendment, and then make the changes using [brackets] to delete and underline for new material:
    1. The quick brown fox jumps over the lazy dog. Please Excuse My Dear Aunt Stacey.
    2. The quick brown fox jumps over the lazy dog. Please Excuse My Dear Aunt [Stacey] Sally.
  2. 2. Claims:
    1. Amend Claim 1 as follow: … amended claim written in its entirety with markup ….
    2. Cancel claim 6. (nothing further needed, no need to bracketize the canceled claim).

1454: Appeal Briefs: You can have an appeal on a reissue app just as on a normal app. However, unlike in a normal apeal where the claims are written out without showing how they have been amended, (not using the editor’s markup) claims on reissue should show the markup in order to show the changes that have occurred during the reissue process (including new claims that should be in the all-underline format seen above).

1455: Allowance & Issue for Reissue Apps:
The stuf omitted from the original patent is in [brackets] but stuff added in the reissue is in italics and NOT underlined! (remember this is the final publication once the reissue is allowed & published).
At least one of the claims from the reissue has to be published in the USPTO’s Official Gazette (for making it publicly known)
All dependent claims that are allowed but have a parent independent claim not-allowed must be rewritten in independent form.

1460: What effect does Reissue have on a Patent:
35 U.S.C. 252: Basically, the granted reissue patent will be treated as if the originally granted patent had contained all the disclosures/claims in the reissued patent.

1470 Public Access: 37 CFR 1.11(b): All reissue apps are open to inspection by the public, and they are also anounced in the USPTO’s official gazette.

1480: Certificates of Correction: When the Office Makes a Mistake.

  1. Under 37 CFR 1.322 the Office may correct the mistake with a certificate of correction, but it is not obligated to do so (35 U.S.C. 254).
  2. Third parties lack standing to demand corrections, but they are allowed to submit info to the Office if they find mistakes.
  3. 1480.01: If the patentee makes a request showing evidence that the Office is solely responsible for a mistake, the Office will attempt to expedite the correction under 37 CFR 1.322.

1481: When the Applicant Makes a Mistake:
These corrections are under 35 U.S.C. 255; 37 CFR 1.323 for when the Office is not responsible for a mistake. If mistakes are not correctable via the certificate of correction, then the applicant should file a reissue app to correct them instead.

Two prong analysis for deciding if a certificate of correction may be used:

  1. 1. Look at the type of mistake it must be in one of these categories:
    1. 1. clerical error
    2. 2. typographical error; or
    3. 3. mistake of ‘minor character’
  2. 2. Additionally, the correction to the mistake itself must not involve changes that would create:
    1. 1. New matter (major no no, not even reissue allows these) or
    2. 2. require a reexamination (a reissue app could be used).