Patent and Trademark Depository Library Program

Conducting a Patent Search at a
Patent and Trademark Depository Library (PTDL)

The 7-Step Strategy

1. Index to the U.S. Patent Classification (paper or CD-ROM)

   Begin with this alphabetical subject index to the Manual of Classification. Look for common terms describing the invention and its function, effect, end-product, structure, and use. Note class and subclass numbers.

2. Manual of Classification (paper or CD-ROM)

   Locate class and subclass numbers in the Manual. Note where the terms fall within the U.S. Patent Classification System. Scan the entire class schedule, paying attention to the dot indent. Revise search strategy as needed.

3. Classification Definitions (microfiche or CD-ROM)

   Read the definitions to establish the scope of class(es) and subclass(es) relevant to the search. The definitions include important search notes and suggestions for further search.

4. Patents BIB (CD-ROM or Automated Patent System (APS) Text)

   Check if you are on the right path; search Patents BIB (1969-present) for a particular class/subclass; retrieve results and examine titles. Try other relevant classes/subclasses. Revise your search by using applicable keywords; note the classes and subclasses and go back to 2.

5. Patents CLASS (CD-ROM or APS TEXT)

   Once relevant class(es)/subclass(es) are identified, obtain a list of all patent numbers (1790-present) granted for every class and subclass to be searched.

6. Official Gazette - Patent Section (paper or microform)

   Go to the Gazette and look for exemplary claim(s) and a representative drawing for all patents on the list(s) to eliminate patents unrelated to the invention.

7. Complete Patent Document (microfilm, paper, CD-ROM, or APS IMAGE)

   Search the complete text and drawing(s) of closely related patents to determine how different they are from the invention.