Brief context

  • I'm in the early stages of product development, pre-prototype. (Subtext: definitely no funds available for a legal opinion. I'll cross that bridge when it becomes feasible; for now, I'm just looking for a better understanding how prior art is generally interpreted in cases like this one.)
  • Bad news: there is an active US patent that covers my concept (most claims are relevant and not easily designed around).
  • Good news (probably): I've found a few instances of prior art that anticipate the patent, invalidating the relevant claims (my own non-lawyerly opinion of course). However, that depends on how the prior art is interpreted, as the patent is not a carbon copy of the prior art.
  • The company does not appear to be practicing the patent anymore (nor are there any other companies doing so), so I don't see a need to go out of my way to invalidate it, but I'm doing a bit of homework now in case at some point in the future, the patent holder makes a fuss.
  • (I recognize that to show invalidity you have to show "that the patent is invalid by clear and convincing evidence, a substantially greater burden" than proving infringement https://chicagounbound.uchicago.edu/cgi/viewcontent.cgi?article=5529&context=journal_articles)
  • (I'll keep this post focused on an issue regarding one instance of prior art; I've made another post regarding a different issue regarding another instance of prior art.)

Rather than citing the patent or prior art here, I'll lay out the key issue in general terms; for the sake of making the discussion a bit less abstract, I'll pretend here that the patent and the prior art refer to bicycles.

  • I've found a blog post (via a search on Google, i.e., the post is publicly accessible) dated a couple of years before the patent's priority date
  • (Note: the blog post is not cited in the patent or its examination.)
  • The blog post describes a bicycle that fits the description of the bicycle described in the patent's claims, apart from minor differences. (The most notable difference is that the bicycle in the blog includes an additional element not described in the bicycle in the patent—but the patent doesn't exclude the possibility that that element could be included—e.g., its claims all use the structure "a bicycle comprising a, b, c..." . Also, a person can still use the bicycle with the additional element in the same way as the bicycle without that element.)
  • The blog post, however, is quite brief. It includes an image which is simply a cropped photograph of part of one bicycle pasted beside a cropped photograph of part of another bicycle, together creating a kind of chimeric bicycle, all done with clunky, beginner-level photo editing. The very brief accompanying text basically says "bicycle type X and bicycle type Y are well-known, and the usefulness of this part of X and this part of Y are well-known, so why don't we see any XY bicycles that are made by simply taking this part of X and mashing it up with this part of Y, like I illustrated in this photo?"
  • The description goes no further; there is no description of the relevant parts of X and Y. However, I think a person of ordinary skill would easily understand from the very brief text and the image how to make the bicycle described in the blog post.
  • (In fact, I think even without the blog post giving the brief description and illustration, the XY bicycle would be obvious to a practitioner of ordinary skill, but my sense is that arguing for obviousness would be a riskier path, and unnecessary anyway if there is an argument that the blog discloses the XY vehicle.)

The question is: how explicit and detailed does this instance of non-patent prior art need to be in order to invalidate the patent?

According to one section of the Manual of Patent Examining Procedure (https://www.uspto.gov/web/offices/pac/mpep/s2152.html#ch2100_d20033_1da60_2e9), the prior art document must disclose every element of the claim "explicitly or inherently", “arranged or combined in the same way as in the claim", and it must enable the person of ordinary skill to make the invention "without undue experimentation."

This reference from the MPEP seems encouraging: while the blog post doesn't explicitly list the various elements of X and Y, those elements are inherent in X and Y, I think.

Another encouraging reference from another section of the manual (https://www.uspto.gov/web/offices/pac/mpep/s2164.html#d0e215634) says that the amount of guidance needed to enable the invention is low in "predictable arts", like bicycle inventions.

Based on my reading of those references from the manual, it seems that the blog post describing the bicycle, though it contains only a very brief description and a rudimentary illustration, would be sufficiently enabling.

Am I on the right track, or am I missing something crucial?

And, not that I want to get too much deeper into this, but can anyone recommend any brief discussions of relevant cases (ideally, in a "predictable art") where non-patent prior art that contained relatively brief description was considered sufficiently enabling to invalidate a patent claim?

  • If the patent has expired, why are you worried? Once a patent expires, anyone can use the invention described by its claims free of charge.
    – Eric S
    Apr 4, 2019 at 2:44
  • It's an unexpired patent, not an expired one—I guess that was an awkward choice of wording, I should have said "active".
    – user1
    Apr 4, 2019 at 3:19
  • A difference in treatment between a patent as prior art and a non-patent reference as prior art is that a patent (expired or not) is presumed to be enabled.
    – George White
    Apr 4, 2019 at 6:25

1 Answer 1


(Note: the blog post is not cited in the patent or its examination.)

This gives the added advantage as the same has not been examined the page could be a potential Novelty destroyer for the patent.

how explicit and detailed does this instance of non-patent prior art need to be in order to invalidate the patent?

The actual scenario would differ case by case. If the prior art describes the same invention from the blog apart from the minor improvements then, please look into the claims. Are the claims scope limited for the minor improvement because the minor improvements ? as such improvements are always patentable.

As for you question how detailed the prior art must disclose depends on An ordinary person skilled in the art (POSA), upon reading the blog could arrive at such invention under any of the two categories.

  1. can such improvement be anticipated based on that blog post (does the post describes the invention within the four corners of the page)
  2. Is it obvious for a POSA to arrive at that invention upon combination of blog with some other document (Eg: The blog describes a cycle without suspension and there is Moped with suspension. To improve the comfort of the cycle ride combining the suspension of moped with cycle to improve would have been obvious as the same is achieved when used in cycle or moped)

In brief the prior alone (blog) alone or in combination with some other document could it be possible for a person skilled in the art to arrive at that invention is the factor that has to be considered in evaluating the prior art.

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