Does Size Matter in Patent Claims?

July 28, 2021
By Victor Krichker, Callum Lootsma and Raffi Dergalstanian


Making an article smaller can often have valuable benefits and requires inventive ingenuity to accomplish. However, it is often difficult to convince the US Patent and Trademark Office (USPTO) that a smaller article or dimension is deserving of a patent. USPTO Examiners often view such inventions with suspicion because such scaled-down inventions can appear simple at first glance and with benefit of hindsight.

One such situation was the subject of a decision of the US Patent Trial and Appeal Board (“Board”) in Ex parte Drozdenko (Appeal No. 2020-001293). At issue in the Board decision was the rejection by the Examiner of independent claim 1 and several other claims in US patent application 15/039,929 (“Drozdenko”). Claim 1 related to an airfoil, which claimed a certain size of holes in a woven fabric layer. The Examiner rejected this claim asserting that it was obvious for the Applicant to choose a woven fabric layer having holes that are on average less than 0.001 inches. In re Rose1 (“Rose”) the Board was asked to determine whether the Examiner’s obviousness rejection based on scaling of size was justified. Ultimately, the Board overturned the Examiner’s final rejection. This decision demonstrates possible strategies for rebutting an Examiner’s size-based obviousness rejections.

Reasoning of the Board

In rejecting claim 1 of Drozdenko, the Examiner relied on the previous decision In re Rose (“Rose”) for the proposition that a change in size is generally recognized as within the knowledge of ordinary skill in the art.

In Rose, the inventor claimed a method of transporting large packages of lumber.  However, the prior art disclosed methods of transporting smaller packages of lumber arranged in a similar manner to the inventor’s application. The inventor argued that the claimed “lumber package” required a lift truck for handling due to its large size. However, this argument was rejected on the basis that the claimed “invention” was merely a scaling up of the entirety of the prior art with no inventive concept. Thus, the court held that that “this limitation [(i.e., size and weight of the package)] is [not] patentably significant since it at most relates to the size of the article under consideration which is not ordinarily a matter of invention.”2

Returning to Drozdenko, the Board overturned the Examiner’s rejection for two reasons. First, the Board stated that the Examiner did not demonstrate that the substitution made by the Applicant was an obvious matter of design choice. In Drozdenko, the Examiner did not propose a change to the overall size of the article under consideration. Instead, the Examiner proposed changing the structure of the woven fabric to a tightly woven fabric; a change that goes to the very structure and function of the claimed article. The Board, in rejecting the Examiner’s position, cited In re Gal3, which held that a finding of an obvious design choice is precluded when the claimed structure and the function it performs are different from the prior art. Second, the Board stated that the Examiner did not adequately articulate reasons as to why one of ordinary skill in the art would have been motivated to make the substitution proposed by the Applicant.

Other Size-Based Decisions

A similar situation arose in Ex parte Jones (Appeal No. 2019-003085). In this case, the Board reviewed an obviousness rejection made by the Examiner relating to aircraft miniaturization, and more specifically, to gas turbine engine miniaturization. The cited prior art showed most of the claimed structure, however, the prior art disclosed a full-sized airplane. The Examiner, relying on In Gardner v TEC Syst, Inc.4 (“Gardner”), argued that the claimed invention was obvious because it was simply a change in scaling of the prior art. In that case, most of the applicant’s claimed invention was disclosed in the prior art, but at a much larger scale. However, there were components in the applicant’s invention that, when miniaturized, completely changed the overall structure. Thus, the applicant argued that the structure relied on by the examiner in the prior art would be inoperable if one tried to miniaturize the engine.

The Board, in Ex parte Jones (“Jones”), accepted the Applicant’s arguments, stating that the Examiner’s finding was lacking evidentiary support. The Board looked to the specific facts in Gardner and the evidence available (or lack thereof) to the Examiner and determined that the Examiner’s inquiry into why the engine could not be miniaturized was inappropriate. The Board states that the burden is on the Examiner to make a prima facie case of obviousness, and that this determination requires an analysis of the evidence. Therefore, it is imperative that Examiners pay careful attention to the specification and understand how changes in size affect the structure of a claimed invention, just as the Board did in both Drozdenko and in Jones.

A similar situation arose in Ex parte Rosenberg (Appeal No. 2019-003746). In this case, the Examiner rejected the Appellant’s claims, which were directed at a motorized pet toy with a long shaft in a hollow shell. The Examiner relied on In re Rose to reject the claims, asserting that “it would have been an obvious matter of design choice to make the housing larger or the wand/ball smaller in order to allow the device to operate, since such a modification would have involved a mere change in the size of a component.” However, the Board rejected this assertion, noting that merely stating a particular limitation is a design choice does not make it obvious. The Board went on to state that “the Examiner must still provide a reason for one of ordinary skill in the art, ‘without the benefit of the appellant’s specification, to make the necessary changes in the reference device.’” Ex parte Rosenberg is yet another example of an Examiner making an assertion about a claim without proper justification or evidence.

Practice Points

As can be seen in Drozdenko, rejections of claims directed to smaller or larger dimensions relying on Rose may be misapplied by Examiners when asserting that changing the size of a particular component is an obvious design choice. Drozdenko serves as a guide for the importance of determining whether the resizing in question is for the entire article or only a component. If it is only a component being resized, then the Examiner’s reliance on Rose may be inappropriate. It is also important to consider whether the change in size results in a different function or performance of the claimed invention than that by the prior art.

1220 F.2d 459, 105 USPQ  237 (CCPA 1955).

2In re Rose, 220 F. 2d 459, 105 USPQ 237 (CCPA 1955) at 822.

3980 F. 2d 717, 719 (Fed. Cir. 1992).

4725 F.2d 1338, 220 USPQ 777 (Fed. Cir. 1984), cert. denied, 469 U.S. 830, 225 USPQ 232.

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