Under current U.S. Patent Law, WIPO publications and issued or published U.S. patent documents may qualify as so-called secret prior art i.e. patent documents issued or published after the effective filing date of a U.S. patent application, but filed prior to the filing of the application[1].  These prior art references are referred to as being ‘secret’ because they become publicly available only after an applicant files a patent application.

The effective date of secret prior art is determined by several factors under current U.S. Patent Law.  For issued or published U.S. patent documents which claim priority only to an earlier filed foreign patent application, the effective date is the actual filing date of the application under section 102(e) of current U.S. Patent Law.  That is, the filing date of the foreign priority application cannot serve as the effective date under section 102(e) in this case.

The Patent Reform Act of 2011 (Senate Bill S.23) appears to eliminate WIPO publications as secret prior art, and expand the class of U.S. issued patents and published applications which qualify as secret prior art.

The Patent Reform Act of 2011 (also referred to herein simply as ‘the Act’) was considered in committee earlier this year, and recommended for consideration by the full Senate.  One major provision which has received much attention is the proposed shift from the traditional first-to-invent system in the U.S. to a first-to-file system.  The proposed first-to-file system includes limited safeguards exempting certain pre-filing inventor activity.[2]

However, secret prior art continues to remain available under the proposed first-to-file system.  Particularly, section 102(a) of the Act in current form reads as follows:

A person shall be entitled to a patent unless–

‘(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention; or

‘(2) the claimed invention was described in a patent issued under section 151, or in an application for patent published or deemed published under section 122(b), in which the patent or application, as the case may be, names another inventor and was effectively filed before the effective filing date[3] of the claimed invention.

To qualify as secret prior art under section 102(a)(2) of the Act, a patent document must be issued under section 151 or published or deemed published under section 122(b).  This is a significant departure from section 102(e) of current U.S. Patent Law in that WIPO publications presumably no longer qualify as secret prior art under the Act.

In addition, the U.S. patent document must be effectively filed before the effective filing date of the claimed invention to qualify as prior art under §102(a)(2) of the Act.

Section 102(d) of the Act defines the effective filing date of U.S. patent documents i.e. U.S. issued patents and published applications.  Namely, section 102(d)(2) specifies the effective filing date of a U.S. patent document as the filing date of the earliest application that describes the subject matter and to which a right of priority is claimed under section 119, 365(a), or 365(b), or to which the benefit of an earlier filing date is claimed under section 120, 121, or 365(c).  Otherwise, the effective filing date is the actual filing date of the U.S. patent document according to section 102(d)(1).

Issued U.S. patents and patent publications which claim priority only to earlier filed foreign applications therefore have an earlier effective filing date under section 102(a) of the Act as compared to section 102(e) of current U.S. Patent Law.  To highlight the differences, consider Example 3 given in section 706.02(f)(1) of the MPEP.  In this example, the section 102(e) effective date is determined for a U.S. patent application filed on 16 August 2001, published on 14 March 2002 and issued on 01 November 2003.  The application claims priority to an earlier U.S. application filed on 21 June 1999, which in turn claims priority to a foreign application filed in Japan on 22 June 1998.  In this example, the effective date of the later-filed published U.S. application under section 102(e) of current U.S. Patent Law is 21 June 1999, the filing date of the earlier-filed U.S. application.  The filing date of the priority Japanese patent application does not serve as the effective date of the U.S. patent publication under section 102(e) in view of In re Hilmer, 149 USPQ 480 (CCPA 1966).

However, the effective date for this same U.S. patent document would be the filing date of the priority Japanese patent application under proposed section 102(d)(2) of the Act.  In another example, there is no earlier-filed U.S. patent application and only a perfected foreign priority claim.  In this case, the effective date of the published U.S. patent application as prior art is the actual filing date of the U.S. patent application under section 102(e) of current U.S. Patent Law whereas.  Under section 102(d)(2) of the Act, the effective date of the reference is the filing date of the foreign priority application.

If passed into law as currently written, the Patent Reform Act of 2011 presumably eliminates WIPO publications as secret prior art.  The Act also rolls back the effective filing date for U.S. patents and published applications which claim priority to only earlier-filed foreign patent applications.

Going forward, certain technical classes of inventions may be subject to more prior art than other classes under the Act.  For example, many semiconductor companies are located in the Far East.  These companies may chose to file for patent protection first in Japan, Korea or China and then file subsequent applications in the U.S. claiming priority to one or more earlier filed foreign patent applications.  Such prior foreign filing activity gives rise to a new class of secret prior art references under section 102(a) of the Patent Reform Act of 2011 which did not exist under section 102(e) of the current Patent Law, or at least these U.S. patent documents will have an earlier effective date as prior art under the proposed law.


[1] See 35 U.S.C. §102(e).

[2] See §102(b) of the Patent Reform Act of 2011.

[3] According to §100(a)(i)(1) of the Patent Reform Act of 2011, the effective filing date of a claimed invention is either (1) the actual filing date of the patent or application for patent containing a claim to the invention or (2) the filing date of the earliest application for which the patent or application is entitled to a right of priority under section 119, 365(a), or 365(b) or to the benefit of an earlier filing date under section 120, 121, or 365(c).