E.g. assume first-filed application X disparages the prior art, thus implicitly disclaiming that scope. Does later-filed application Y filing a terminal disclaimer over app X also lose this claim scope even if the app Y on its own would otherwise be considered to retain the scope?

A similar case could arise for parents of continuation applications that have created prosecution history estoppel (e.g. characterize a claim term in a limiting way in an office action response).

Edit: Case law evidence to support a finding either way is desirable.

  • I have to admit I have no idea what you are asking. How does one disparage prior art? Could you perhaps edit the question for clarity?
    – Eric S
    Commented Apr 25, 2018 at 1:11
  • @Eric Shain - one disparages prior art by writing that the prior art doesn't work well in certain cases, or has particular decencies. This was once common in applications. It is no longer recommended because it could be taken by a judge to limit your claim scope narrower than your claim words. If you said the prior art was horrible because it didn't work in the rain and someone infringed the words of your claim but argued that it didn't infringe because it also didn't work in the rain. You implied that anything that doesn't work in the rain isn't your invention.
    – George White
    Commented Apr 25, 2018 at 1:29
  • @GeorgeWhite Thanks, that makes sense. I still don't understand the question. Of course I am not a lawyer...
    – Eric S
    Commented Apr 25, 2018 at 1:38
  • 1
    @EricShain if I invented a car instead of a motorcycle because it has a roof and someone invents a car without a roof even though the roof was actually pretty optionable for my invention, but I said in the decription that the main feature over the prior art "motorcycle" was not getting wet, (then I made a mistake) then I might not be able to claim infringement for the car without roof. The question is, if I do that in an application which is then linked to another application (continuation, TD), does the other application have that too?
    – user18033
    Commented Apr 25, 2018 at 6:23
  • @DonQuiKong Correct, that's what I'm trying to ask.
    – user132162
    Commented Apr 26, 2018 at 1:06

2 Answers 2


"Disparaging" prior art does not automatically disclaim scope. Previously it was good practice to characterize prior art for its strengths and weaknesses - particularly weaknesses. Then some judges decided to read the specification into the claims and say that the the inventor must have meant to only claim less than was claimed. Another problem with characterizing prior art is that you might be in error when you say some prior art device has some specific weakness or limitation. Maybe that was covered on page 201 of the prior art and you didn't see it. You could be accused of hiding the ball and otherwise misleading the examiner. In fact, even calling something prior art is a no-no. There may be a technicality of dates or non-analogous fields that makes it arguable that a specific reference is not actually prior art. Unless you have said it was prior art - then it is admitted prior art you are stuck with.

So, to generalize your question - can disparaging prior art, or other "patent profanity" spill from one of an inventor's applications into another related application? My view is that it wouldn't make sense but worse twisting of the patent laws/rules have happened.

  • Thanks for your answer. I learned a little something today!
    – Eric S
    Commented Apr 25, 2018 at 20:41
  • I don't see why it's unreasonable that "some judges decided to read the specification into the claims". Prosecution history can be considered to narrow claim scope by distinguishing over the prior art. So too can the specification, which according to the CAFC generally holds more weight than pros history.
    – user132162
    Commented May 16, 2018 at 16:14
  • Also, although disparagement is not dispositive of a disclaimer, to disparage an embodiment and then attempt to claim it seems to be "hiding the ball" a bit, as presumably an embodiment was disparaged to distinguish the "inventiveness" of what is claimed.
    – user132162
    Commented May 16, 2018 at 16:16
  • Using the specification to interpret the claims is proper. To override the plain meaning of the claim wording is not proper.
    – George White
    Commented May 17, 2018 at 0:15

TDs aside, patent families may share prosecution history estoppel. From article:

When one or more continuation or divisional applications are subsequently filed, as is often the case, the scope-limiting estoppel may similarly effect those related children applications.


To avoid the cascade of disclaimer and estoppel from parent to child applications, affirmative rescission of the disclaimer can be utilized to recapture the disclaimed subject matter.

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