How to Read Your Own Patent: A Plain-English Guide

Read your patent in this order: the front page (who, what, when), the independent claims (what the patent legally covers), the figures (what it looks like), and then the description (how it works). The claims, not the title, abstract or description, set the legal boundaries of the patent.

This guide is general information, not legal advice; talk to your patent attorney about your situation.

The front page

The front page summarizes the patent. The small numbers in parentheses are INID codes, an international standard (WIPO ST.9) used on patents worldwide, so once you learn them you can read the front page of almost any patent.

Look for a line marked "Notice." It may say the term was extended or adjusted under 35 U.S.C. § 154(b) by a number of days (patent term adjustment), or that the patent is subject to a terminal disclaimer, which can shorten it.

Kind codes: what the letters mean

The letter and digit after a US number have followed WIPO Standard ST.16 since January 2, 2001:

US applications are generally published promptly after 18 months from the earliest filing date, which is why B2 is common. B1 means the application was never published before grant, for example because the applicant requested nonpublication or the patent issued before the 18-month mark.

The parts of the description

The specification follows a standard order: cross-references to related applications, background, summary, brief description of the drawings, detailed description, claims and abstract.

The detailed description walks through one or more examples, often introduced as "in one embodiment." These are examples. The patent can reach further than them, or not as far. The claims decide.

Claims: where the legal scope lives

Under 35 U.S.C. § 112, a patent must end with claims that "particularly point out and distinctly claim" the invention. Each claim is written as a single sentence, starting with a capital letter and ending with a period. A claim has three parts:

• Preamble. What the claim is about: "A bicycle lock"
• Transition. Usually "comprising," which is open-ended: a product with extra parts can still fall within the claim. "Consisting of" is closed and excludes anything not listed.
• Body. The elements or steps, each usually on its own indented line.

Here is an invented example:

1. A bicycle lock, comprising: a shackle; a body having a keyway; and a sensor that detects when the shackle is cut.

2. The bicycle lock of claim 1, wherein the sensor triggers an alarm.

Claim 1 is independent. It stands on its own. Claim 2 is dependent. It refers back to claim 1 and adds a limitation, and by statute it includes everything in claim 1. So claim 2 is narrower: it covers only locks with the shackle, keyway, cut sensor and alarm.

Why have both? If claim 1 were ever found invalid over prior art, a narrower dependent claim might survive. Many patents have more than one independent claim, often one for a device and one for a method, so find them all. They are the claims that do not say "of claim."

A useful exercise: rewrite each independent claim as a bulleted list of what it requires. That list is your patent's footprint.

Figures and reference numerals

The drawings show embodiments. The numbers on them are reference numerals, and USPTO rules make them consistent: the same part gets the same numeral in every view, one numeral never labels two different parts, and every numeral in the drawings must be mentioned in the description.

That makes them a navigation tool. If you want to know what part 24 is, search the text for "24." US claims may repeat numerals in parentheses, but many do not.

Where to find your patent and its history

• Patent Center holds your official eGrant and the file history: every office action, amendment and response. What was argued or amended to get the patent allowed can affect how the claims are read, so skim it.
• USPTO Patent Public Search and Google Patents give free full text and drawings.
• To see your patent's claims and drawings on screen, try a free instant trailer, available for US patents granted since about 2001.

A 20-minute reading plan

1. Front page: confirm number, kind code, dates, inventors and owner. (3 minutes)
2. Find every independent claim and list its elements. (7 minutes)
3. Match each element to a figure and reference numeral. (5 minutes)
4. Read the summary and skim the detailed description for anything unclear. (5 minutes)

Next steps: see what to do after your patent is granted or how to explain it to investors.

Sources

• WIPO Standard ST.9, bibliographic data on patents (INID codes): https://www.wipo.int/documents/d/standards/docs-en-03-09-01.pdf
• USPTO, Kind codes included on USPTO patent documents: https://www.uspto.gov/learning-and-resources/support-centers/electronic-business-center/kind-codes-included-uspto-patent
• 35 U.S.C. § 112, specification and claims (Cornell LII): https://www.law.cornell.edu/uscode/text/35/112
• 35 U.S.C. § 122, publication of applications (Cornell LII): https://www.law.cornell.edu/uscode/text/35/122
• 35 U.S.C. § 154, term and term adjustment (Cornell LII): https://www.law.cornell.edu/uscode/text/35/154
• 37 CFR 1.77, arrangement of application elements (Cornell LII): https://www.law.cornell.edu/cfr/text/37/1.77
• 37 CFR 1.84, drawing standards and reference characters (Cornell LII): https://www.law.cornell.edu/cfr/text/37/1.84
• USPTO, MPEP 2111.03, transitional phrases: https://www.uspto.gov/web/offices/pac/mpep/s2111.html
• MPEP 608.01(m), form of claims (BitLaw): https://www.bitlaw.com/source/mpep/608-01-m.html
• USPTO, Patent Public Search: https://www.uspto.gov/patents/search/patent-public-search
• USPTO, Patent number formats: https://www.uspto.gov/patents/apply/applying-online/patent-number