Ex Parte Larson

Board of Patent Appeals and Interferences

Feb 9, 2006

10028173 (B.P.A.I. Feb. 9, 2006)

The opinion in support of the decision being entered today was not written for
publication and is not binding precedent of the Board.

UNITED STATES PATENT AND TRADEMARK OFFICE

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BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
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Ex parte JAMES MICHAEL LARSON
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Appeal No. 2006-0435
Application No. 10/028,173
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ON BRIEF
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Before CAROFF, OWENS, and FRANKLIN, Administrative Patent Judges.

CAROFF, Administrative Patent Judge.

DECISION ON APPEAL

This is a decision on appeal from the examiner’s final
rejection of claims 1-5. Claims 6-17, the other pending claims
in appellant’s application, stand withdrawn from consideration by
virtue of the imposition of a restriction requirement by the
examiner. Accordingly, only claims 1-5 are before us on appeal.

The appealed claims relate to a method of making a gas
diffusion layer (GDL) for an electrochemical cell which includes

the step of compressing a coated carbon cloth substrate to a
compression of 25% or greater.
Appellant makes no significant distinction between the
individual claims in advocating for patentability. Accordingly,
all of the claims at issue are considered as standing or falling
with independent claim 1 for purposes of this appeal. In re
King, 801 F.2d 1324, 1325, 231 USPQ 136, 137 (Fed. Cir. 1986).
Claim 1 reads as follows:
1. A method of making a gas diffusion layer for an electro- chemical cell
comprising the steps of:

a) providing a plain-weave carbon fiber cloth;

b) coating a surface of said plain-weave carbon fiber cloth with a layer
comprising carbon particles and one or more highly fluorinated polymers to make a
coated plain-weave carbon fiber cloth; and

c) compressing said coated plain-weave carbon fiber cloth to a compression of
25% or greater; wherein said step of compressing does not include attaching said plain-
weave carbon fiber cloth to another layer.

The prior art references relied upon by the examiner are:
Allen et al. (Allen) 4,293,396 Oct. 6, 1981
Fan et al. (Fan) 2002/0134501 A1 Sept. 26, 2002

All of the appealed claims stand rejected for obviousness under 35 U.S.C. §
103(a) in view of Allen taken in combination with Fan.

We have carefully reviewed the record in this case in light of the opposing
positions taken by the appellant and by the examiner. Having done so, we are firmly
convinced that the prior art references relied upon by the examiner support a prima
Appeal No. 2006-0435
Application 10/028,173

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facie case of obviousness. Accordingly, we shall affirm the rejection at issue.
The basis for our decision follows.
As noted by the examiner, Allen teaches forming a GDL or electrode for
electrochemical cells essentially as claimed. However, Allen is silent with regard to any
need for a compression step.
Fan also teaches a method for producing similar GDL electrodes where the
product (a coated carbon cloth) is rolled between two rolls which exert a force on the
cloth sufficient to substantially eliminate cracks in the coating (Fan: designated
paragraphs 30 and 31).
In view of the foregoing, we agree with the examiner that it would have been
prima facie obvious, within the context of 35 U.S.C. § 103, to apply compression to the
GDL electrode of Allen to obtain the benefit (elimination of cracking) taught by Fan.

Appellant is of the view that since the purpose of the rolling step in Fan is to
eliminate cracks in the surface coating on the GDL cloth, an ordinary artisan would
expect that only “superficial deformation” of the surface would be required to obtain the
desired result.
We disagree with appellant on this point for two basic reasons.
First, we are of the opinion that a person of ordinary skill in this field would
understand that a substantial compression of the GDL may very well be necessary to
Appeal No. 2006-0435
Application 10/028,173

4
effectively eliminate or reduce cracking of the surface coating in view of the soft, pliant
nature of the underlying cloth substrate. In other words, in order to generate sufficient
force on the surface coating from the rolls, an ordinary artisan might well expect that the
cloth substrate would have to be substantially compressed. In this regard, we note that
the cloth substrate is generally a porous fabric according to Allen.
Second, we note that at least in some applications the coating layer is likely to be
present throughout a significant portion of the cloth as in Allen (col. 5, lines 16-22).
Certainly in those applications an artisan would understand that

the requisite compression/deformation necessary to prevent cracking of the coating may
very well require more than superficial compression of the entire coated cloth. In this
context we are well aware that Fan (page 2, para. 20) does not require impregnation of
the carbon cloth and, indeed, considers it undesirable. Nevertheless, where
impregnation is mandated (as in Allen), the requisite compression to reduce cracking
would no doubt be considerable. Appellant has not shown otherwise.
Thus, selection of a particular value or range for a recognized result-effective
variable (here compression or compressive force) to achieve optimum results is
considered to be, prima facie, within the realm of ordinary skill absent a showing of any
unexpected result. See In re Boesch, 617 F.2d 272, 276, 205 USPQ 215, 219 (CCPA
1980); In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955).
Appeal No. 2006-0435
Application 10/028,173

5
Appellant also argues that his invention relates to the manufacture of a GDL
which can be incorporated into a membrane electrode assembly (MEA), which includes
a polymer electrolyte membrane (PEM), without increased shorting across the PEM
even when the MEA is under compression. In contrast, the rolling step

of Fan is for the stated purpose of eliminating cracks in a surface coating.
This argument is unpersuasive essentially because appellant’s claims are not
limited to an MEA-type electrochemical cell which includes a PEM and, thus, relates to
a GDL which may be used in another type of electrochemical cell.
Furthermore, at best appellant may have observed yet another advantage
flowing from the teachings of the prior art. However, observation of another benefit
which results from following a suggestion in the prior art is not ordinarily sufficient to
establish a basis for patentability. In this context, see In re Woodruff, 919 F.2d 1575,
1578, 16 USPQ2d 1934, 1936 (Fed. Cir. 1990); In re Kronig, 539 F.2d 1300, 1304, 190
USPQ 425, 427-28 (CCPA 1976); In re Lintner, 458 F.2d 1013, 1016, 173 USPQ 560,
562 (CCPA 1972); In re Swinehart, 439 F.2d 210, 212-13, 169 USPQ 226, 228-29
(CCPA 1971).
For the foregoing reasons, the decision of the examiner is affirmed.

Appeal No. 2006-0435
Application 10/028,173

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No time period for taking any subsequent action in connection with this appeal
may be extended under 37 CFR
§ 1.136(a)(1)(iv).
AFFIRMED

MARC L. CAROFF )
Administrative Patent Judge )
)
)
) BOARD OF PATENT
TERRY J. OWENS ) APPEALS
Administrative Patent Judge ) AND INTERFERENCES
)
)
)
BEVERLY A. FRANKLIN )
Administrative Patent Judge )

Appeal No. 2006-0435
Application 10/028,173

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