I am in the process of prosecuting a U.S. Patent application and have a concern regarding the way the examiner wants to change the wording of three of my claims.

The examiner states that the claims lack antecedent basis and that “the” should be amended to “a” in these claims. However, this change would introduce a confusing element to the claims in my opinion.

One of the claims in question is claim 3 in which the point at issue comes a little over half way through the claim….

  1. (Currently amended) A device according to claim 1, wherein the indicator member comprises a linear indicator extending through the single point, the static member comprises a substantially transparent sphere for containing the linear indicator so that the linear indicator is constrained to rotate about the single point located at the center of the sphere (THE EXAMINER WANTS 'A' CENTER OF THE SPHERE), and the actuator arrangement is configured to generate an electromagnetic field, and the linear indicator is adapted to respond to changes in the electromagnetic field to rotate about the single point.

As indicated above the examiner wants to change “the center of the sphere” to “a center of the sphere”.

The problem I have with this is that the grammatical use of the indefinite article “a” in “a center of the sphere” in the context of this sentence indicates one of a plurality of centers without giving preference to a specific one. Of course a sphere can only have one center and therefore “a center of the sphere” is confusing since it suggests that a sphere could have more than one center which is an impossibility.

I pointed out to the examiner that I thought I had introduced antecedent basis for "the" center of the sphere with “a substantially transparent sphere” (see claim 3 above) because a sphere must of necessity have a center. If a sphere MUST have a center, then I would have thought that by introducing "a sphere", an antecedent basis for it's center is introduced.

However the examiner was unimpressed with that argument and stated.....

“A substantially transparent sphere” is just a transparent sphere, you need to “a center of a sphere” first before you may claim “the center of the sphere”.

The examiner states that the basis for rejection of my preference for “the” rather than “a” comes from 35 U.S.C. 122(b) which states that….

“The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.”

I want claim 3 (and the two other claims in question that relate to other necessary properties of a sphere) to be clear and precise in meaning and I am concerned that the examiners recommended change lacks clarity of meaning.

My question is …. Is there a way that I can irrefutably back up my argument that I am introducing antecedent basis for "the center of the sphere" with the introduction of “a substantially transparent sphere” …. because a sphere MUST have a center.

I would like if possible a killer argument that forces him to agree with me!! Perhaps there is a precedent that I could quote.

Or alternatively, could anyone suggest a form of words that I could use that would satisfy the examiner and at the same time give the claim the clear and precise meaning that I require.

3 Answers 3


The rejection can easily be overcome by simply amending the claim to "a substantially transparent sphere having a center". You are currently limited by prosecution history estoppel. A telecon or interview with examiner is your best shot currently as any way you are going to amend claim based on his recommendation but He might have more clear understanding if you have personal one-to-one interaction.

However if you insist on extending the argument, the best case for your argument would probably be Bose Corp. v. JBL, Inc., 274 F.3d 1354, 1359, 61 USPQ2d 1216, 1218-19 (Fed. Cir 2001) (holding that recitation of “an ellipse” provided antecedent basis for “an ellipse having a major diameter” because “[t]here can be no dispute that mathematically an inherent characteristic of an ellipse is a major diameter”).


"Patent Pending Guide's" answer is short but good. I would just add that no patent examiner wants to allow a patent that gets invalidated in court. In this case, I think the examiner is trying to be helpful, including helping to avoid problems later with antecedent basis.

One approach is to take the offered allowance (i.e. make the change the examiner suggests) and, if you really want claims issued with "a" instead of "the", file a continuation application prior to issuance. There is some additional cost associated with doing it this way, but an issued patent with wording you don't love and a pending continuation with the wording you prefer is better than a rejected patent with perfect wording.

  • i am not sure if a broader continuation will work in this case, but certainly a good idea..
    – Pushpak
    Mar 26, 2015 at 4:48

Probably too late to help OP specifically, but, for posterity, OP is right. MPEP 2173.05(e) has lots of case law for "provid[ing] by implication [or "reasonably"] the antecedent basis".

A good compromise is changing "the center of the sphere" to "the center of said substantially transparent sphere".

I personally stick to the convention of "a" for new element, "said" for referring back to an element introduced with "a", and "the" for implicitly present antecedent basis.

My position seems to be nearly identical to Mr. Albrecht's comment on the following page:


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