関連記事を見つけましたので追加します。(from Patent librarian's notebook)
Re-examination certificates are not indexed in the USPTO's web-based patent database. Instead, users can retrieve a copy of the certificate by retrieving the original patent, e.g. by searching the patent number and clicking on the "Images" button to see the TIFF image. The re-exam certificate is attached after the claims section.
The series code 90 is used for ex parte re-examination proceedings (90/009,335) and 95 for inter partes proceedings (95/001,115). Since 1981 there have been approximately 9,500 ex parte re-examinations filed. And 500 inter partes re-exams have been requested since November, 1999.
It is possible to retrieve re-examination filings in the USPTO's Public PAIR (Patent Application Information Retrieval) System. Simply search the re-examination control number (including the series code, e.g. 90/010334). The file wrapper will contain all the documents and forms involved in the re-examination, including a copy of the patent in question, submitted prior art, e.g. patents and non-patent literature.
(from The invent blog)
The easiest way is to search by serial number
- use the “90? series for ex-parte re-examinations,
- use the “95? series for inter-partes.
For example: APN/90005727 is an ex-parte case, APN/95000050 is an inter-partes.”