Ex Parte Durvasula

Board of Patent Appeals and Interferences

Apr 4, 2011

11146875 (B.P.A.I. Apr. 4, 2011)

UNITED STATES PATENT AND TRADEMARK OFFICE
UNITED STATES DEPARTMENT OF COMMERCE
United States Patent and Trademark Office
Address: COMMISSIONER FOR PATENTS
P.O. Box 1450
Alexandria, Virginia 22313-1450
www.uspto.gov
APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO.
11/146,875 06/06/2005 Ravi Shankar Durvasula 155850-1/YOD
(GERD:0424)
5559
41838 7590 04/04/2011
GENERAL ELECTRIC COMPANY (PCPI)
C/O FLETCHER YODER
P. O. BOX 692289
HOUSTON, TX 77269-2289
EXAMINER
TRINH, THANH TRUC
ART UNIT PAPER NUMBER
1725
MAIL DATE DELIVERY MODE
04/04/2011 PAPER
Please find below and/or attached an Office communication concerning this application or proceeding.
The time period for reply, if any, is set in the attached communication.
PTOL-90A (Rev. 04/07)

UNITED STATES PATENT AND TRADEMARK OFFICE
________________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
________________

Ex parte RAVI SHANKAR DURVASULA
________________

Appeal 2010-001625
Application 11/146,875
Technology Center 1700
________________

Before PETER F. KRATZ, CATHERINE Q. TIMM, and
LINDA M. GAUDETTE, Administrative Patent Judges.

GAUDETTE, Administrative Patent Judge.

DECISION ON APPEAL

Appeal 2010-001625
Application 11/146,875

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Appellant appeals under 35 U.S.C. § 134(a) from the Examiner’s
decision finally rejecting claims 1-21, the only claims pending in the
Application.1 We have jurisdiction under 35 U.S.C. § 6(b).
We AFFIRM-IN-PART.
Of the appealed claims, claims 1, 11, 15, and 21 are independent.
Claims 1, 11, and 21 are representative of the invention and are reproduced
below from the Claims Appendix to the Appeal Brief:
1. An energy conversion system, comprising:
a first optical cover comprising a first surface and a
second surface, wherein the first surface comprises a flat
surface and the second surface comprises a patterned surface
configured to receive solar energy from the first surface and
further configured to concentrate and guide the solar energy;
wherein the patterned surface comprises a plurality of
pyramidal structures, or conical structures, or a combination
thereof;
a second optical cover; and
a plurality of photovoltaic cells located between the
patterned surface of the first optical cover and the second
optical cover and configured to receive the solar energy from
the patterned surface and convert the solar energy into electrical
energy.
11. An energy conversion system, comprising:
a first optical cover comprising a first surface and a
second surface, wherein the first surface comprises a flat
surface and the second surface comprises a patterned surface
configured to receive solar energy from the first surface and
further configured to concentrate and guide the solar energy;

1 Appeal Brief filed Apr. 14, 2008 (“App. Br.”).
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a second optical cover comprising a first surface and a
second surface, wherein the first surface comprises a patterned
surface and the second surface comprises a flat surface; and
a plurality of bifacial photovoltaic cells located between
the patterned surface of the first optical cover and the second
optical cover and configured to receive the solar energy from
the patterned surface and convert the solar energy into electrical
energy,
wherein solar energy incident on the photovoltaic cells is
directly transmitted through the first optical cover, or is
transmitted by total internal reflection of the first optical cover,
or is transmitted by total internal reflection of the second
optical cover, or a combination thereof.
21. An energy conversion system, comprising:
a first optical cover comprising a first surface and a
second surface, wherein the first surface comprises a flat
surface and the second surface comprises a patterned surface
configured to receive solar energy from the first surface and
further configured to concentrate and guide the solar energy;
wherein the patterned surface comprises a plurality of equally
spaced horizontal and vertical triangular troughs intersecting to
form a plurality of equally spaced rectangular regions;
a second optical cover; and
a plurality of photovoltaic cells located between the
patterned surface of the first optical cover and the second
optical cover and configured to receive the solar energy from
the patterned surface and convert the solar energy into electrical
energy;
wherein an angle of inclination of each of the plurality of
triangular troughs is selected based on a refractive index of the
first optical cover, width of the photovoltaic cell, and length of
the photovoltaic cell.
Appeal 2010-001625
Application 11/146,875

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Appellant requests review of the following grounds of rejection (App.
Br. 6):
1. claims 1-8, 10-13 and 15-20 under 35 U.S.C. § 103(a) as
obvious over Dahlberg (U.S. 4,291,191, issued Sept. 22, 1981) in view of
Yogev (U.S. 6,020,553, issued Feb. 1, 2000) (Ans.2 3-8);
2. claim 21 under 35 U.S.C. § 103(a) as obvious over Dahlberg in
view of Winston (U.S. 4,240,692, issued Dec. 23, 1980) (Ans. 9-10);
3. claim 9 under 35 U.S.C. § 103(a) as obvious over Dahlberg in
view of Yogev and in further view of Aguilera et al. (U.S. 6,107,564, issued
Aug. 22, 2000) (Ans. 10-11); and
4. claim 14 under 35 U.S.C. § 103(a) as obvious over Dahlberg in
view of Yogev and further in view of Yoda et al. (U.S. 6,528,718, issued
Mar. 4, 2003) (Ans. 11).
Independent claims 1, 15, and 21
Upon consideration of the following two issues raised by Appellant,
we determine the Examiner reversibly erred in rejecting independent claims
1, 15, and 21. Therefore, we reverse the Examiner’s decision to reject
claims 1-10 and 15-21.
Issue 1: Did the Examiner reversibly err in finding that (a) the pyramidal or
conical structures limitation recited in independent claims 1 and 15
encompasses the structures on Yogev’s patterned surface, and (b) the
triangular troughs limitation recited in independent claim 21 encompasses
the troughs in Dahlberg’s patterned surface?

Independent claims 1 and 15 recite “a first optical cover” and a “solar
concentrator,” respectively, comprising “a patterned surface” including “a
plurality of pyramidal structures, or conical structures, or a combination

2 Examiner’s Answer mailed Jun. 24, 2008.
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Application 11/146,875

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thereof.” The Examiner relies on Dahlberg for a teaching of an energy
conversion system, or solar cell arrangement, comprising a first optical
cover having a patterned surface. (Ans. 3, 7-8.) The Examiner concedes
Dahlberg “does not specifically teach the pattern[ed] surface comprises a
plurality of pyramidal structures, conical structures, or a combination
thereof.” (Ans. 4, 8.) The Examiner finds “Yogev teaches an optical cover
having a pattern[ed] surface that comprises a plurality of pyramidal
structures as seen in Figure 1, and the V-shaped grooves (12 and 14)
defining the base area (10) of a patterned structure can follow circular paths
resulting in conical shapes.” (Ans. 4, 8 (citing Yogev col. 3, ll. 18-25).) The
Examiner concludes
[i]t would have been obvious to one of ordinary skill in the art
at the time the invention was made to have modified the system
of Dahlberg by substituting the first optical cover (plate 1) with
an optical cover having the pattern surfaces comprising a
plurality of pyramidal structures, conical structures or a
combination thereof as taught by Yogev, because it would have
provided a geometry of an optical cover that can substantially
directly propagate and/or total internally reflect light onto the
photovoltaic cells.

(Ans. 4, 8.)
Independent claim 21 recites “a first optical cover comprising . . . a
patterned surface . . .; wherein the patterned surface comprises a plurality of
equally spaced horizontal and vertical triangular troughs intersecting to form
a plurality of equally spaced rectangular regions.” The Examiner finds that
Dahlberg teaches an optical cover having a patterned surface comprising
these features. (Ans. 9 (citing Dahlberg Fig. 2).)
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Appellant contends the Examiner erred in finding that the claim 1 and
claim 15 pyramidal/conical structures limitation reads on Yogev’s
“‘truncated cones’ or ‘truncated pyramids’.” (App. Br. 9.) Appellant also
contends the Examiner erred in finding that the claim 21 “triangular troughs”
limitation reads on Dahlberg’s parabolic troughs. (App. Br. 14.)
The respective positions of the Examiner and Appellant are based on
an underlying disagreement as to the scope and meaning of the claim terms
“pyramidal,” “conical,” and “triangular.” Therefore, before considering the
arguments on the merits, we first interpret the claim language in dispute.
Appellant and the Examiner agree the Specification does not
explicitly define the disputed claim terms. (Ans. 13 (as to the terms
“pyramidal” and “conical”); cf. Ans. 20 (as to the term “triangular”).)
Appellant maintains the claim terms “pyramidal” and “conical”
should be interpreted as limited to “structures [which] include side walls that
extend from a base and taper to a point.” (App. Br. 9; see also, Rep. Br.3 3-
4.) Appellant argues the term “triangular” is a common geometric term and
is properly interpreted as “a 3-sided, 3-cornered structure with straight,
planar surfaces.” (Rep. Br. 3; see also, App. Br. 14.)
The Examiner cites to specific figures and paragraphs in the
Specification as supporting a broader interpretation of the claim terms
“pyramidal” and “conical” as reading on Yogev’s truncated structures (Ans.
13). The Examiner maintains “there is nothing in the claim language
indicating a ‘triangular trough’ must have all planar surfaces.” (Ans. 20.)

3 Reply Brief filed Aug. 25, 2008.
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Appellant has persuasively explained why the disclosure relied-upon
by the Examiner fails to support the Examiner’s interpretation of the claim
terms “pyramidal” and “conical.” (See Rep. Br. 4-8.)
Appellant’s proffered definitions of the disputed claim terms are
consistent with the customary meanings of these terms to the ordinary
artisan as evidenced by their dictionary definitions or common usages.
Based on Appellant’s proposed interpretations of the claim terms
“pyramidal,” “conical,” and “triangular,” which we adopt, we agree with
Appellant’s contentions that the Examiner reversibly erred in finding the
claim 1 and claim 15 pyramidal/conical structures limitation reads on
Yogev’s truncated cones/pyramids, and in finding the claim 21 “triangular
troughs” limitation read on Dahlberg’s parabolic troughs.
Issue 2: Did the Examiner reversibly err in finding that (a) Yogev teaches
the use of pyramidal or conical shaped structures would have been a matter
of design choice and easily achievable, and (b) the use of troughs having
planar rather than curved surfaces in Dahlberg’s patterned structure would
have been a matter of design choice?

With respect to claims 1 and 15, the Examiner contends “Yogev
teaches not only the shape of the pattern is just a matter of design choice but
also teaches that it can be achieved easily.” (Ans. 15.) With respect to
claim 21, the Examiner contends “troughs having planar surfaces or curves
[sic] surfaces is just a matter of design choice as supported by the reference
to Yogev.” (Ans. 20.) The Examiner relies, in particular, on Yogev col. 3,
ll. 18-25 in support of these contentions. (Ans. 14-15.)
We agree with Appellant’s position that Dahlberg solely contemplates
the use of parabolic elevations. (App. Br. 14-15; Rep. Br. 3.) We further
agree with Appellant’s assertion that Yogev’s disclosure is limited to
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Application 11/146,875

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patterns of truncated structure, and fails to suggest the use of pyramidal or
conical structures. (Rep. Br. 8-9.) Thus, even if Dahlberg’s optical cover
was replaced with a cover having a pattern as suggested by Yogev, the
resultant optical cover would not have “a plurality of pyramidal structures,
or conical structures, or a combination thereof” as recited in appealed claims
1 and 15.
With respect to claim 21, we agree with Appellant that Dahlberg’s
disclosure is limited to parabolic-shaped troughs (App. Br. 14-16.) We note
the Examiner has not positively included Yogev in the statement of the
rejection. See In re Hoch, 428 F.2d 1341, 1342 n.3 (CCPA 1970) (noting a
reference relied upon to support a rejection, even in a minor capacity, should
be positively included in the statement of the rejection). Thus, Appellant has
persuaded us the Examiner’s evidence is insufficient to establish that it
would have been a matter of design choice to modify the shape of
Dahlberg’s troughs to achieve the invention as claimed in claim 21. (See
generally, Ans. 9-10, 19-21.)
Independent claim 11
With respect to the remaining appealed claims, i.e., claims 11-14,
Appellant’s arguments are limited to independent claim 11. (See generally,
App. Br. 7-13 and 16-17 (discussing the fourth ground of rejection); Rep.
Br. 10-11.) We have thoroughly considered these arguments, but are not
persuaded of reversible error in the Examiner’s conclusion of obviousness as
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to claim 11. The sole issue remaining for our consideration is discussed
below.4
Issue 3: Did the Examiner provide sufficient facts and reasons to support a
finding that Dahlberg’s semiconductor disc having a photovoltaic junction
is a bifacial photovoltaic cell as claimed, and, if so, has Appellant provided
sufficient argument or evidence to refute the Examiner’s finding?

Independent claim 11 recites “a plurality of bifacial photovoltaic cells
located between the patterned surface of the first optical cover and the
second optical cover and configured to receive the solar energy from the
patterned surface and convert the solar energy into electrical energy.”
“[B]ifacial photovoltaic cells[] allow[] the system to capture solar energy[]
directly through the front cover, as well as by total internal reflection (TIR)
within the system.” (Rep. Br. 10.) The Specification describes the operation
of the bifacial cell illustrated in FIG. 4 as follows: “light rays incident on
the bifacial photovoltaic cell 15, are either directly transmitted through the
front cover 12 to the photovoltaic cell 15 or are reflected from the patterned
surface 23 of the back cover 16 and then reflected from the first surface 18
of the front cover 12 prior to impinging the bifacial photovoltaic cell 15.”
(Spec. [0029].) The Specification indicates the ordinary artisan is familiar
with bifacial cells. (Spec. [0028].)
The Examiner finds Dahlberg’s “plate 2 has two concentrators
attached on the top and bottom sides (or the front face and the rear face)”
and that Dahlberg “teaches the concentrators (or the light transmissive
material glass plates) being used to concentrate light on the plate 2 (or

4 We note the remaining arguments raised by Appellant (App. Br. 11-12)
have been fully addressed by the Examiner and are unpersuasive of
reversible error for the reasons explained by the Examiner (Ans. 15-17).
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semiconductor disc having photovoltaic junction . . .).” The Examiner
further finds “[a] semiconductor disc having a photovoltaic junction is
capable of receiving light on both sides (or both faces, front face and rear
face); [therefore,] it must be bifacial.” (Ans. 16-17.)
Appellant argues the evidence fails to support the Examiner’s position
that Dahlberg discloses or suggests bifacial photovoltaic cells as claimed.
(Rep. Br. 10.) Appellant’s argument is based on Dahlberg’s failure to
explicitly identify the disclosed semiconductor disc having a photovoltaic
junction as being bifacial and to discuss the reflective properties within the
system that would allow such a structure. (Rep. Br. 10-11.)
“[W]hen the prior art evidence reasonably allows the PTO to conclude
that a claimed feature is present in the prior art, the evidence ‘compels such
a conclusion if the applicant produces no evidence or argument to rebut it.’”
In re Crish, 393 F.3d 1253, 1259 (Fed. Cir. 2004) (quoting In re Spada, 911
F.2d 705, 708 n.3 (Fed. Cir. 1990)); see also, In re Best, 562 F.2d 1252,
1254-56 (CCPA 1977).
In our view, the Examiner has provided a reasonable basis for
concluding that Dahlberg discloses a bifacial photovoltaic cell as claimed.
Appellant’s arguments fail to directly address the Examiner’s fact finding
and reasoning. In particular, Appellant has not explained why Dahlberg’s
device would not be capable of functioning as a bifacial photovoltaic cell as
proposed by the Examiner. Accordingly, we determine Appellant has not
shown reversible error in the Examiner’s obviousness determination as to
claim 11. Because Appellant has not presented separate arguments in
support of patentability of claims 12-14, which depend from claim 11, we
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likewise determine Appellant has not shown reversible error in the
Examiner’s obviousness determination as to claims 12-14.
CONCLUSION
Based on our consideration of the issues in this appeal:
We REVERSE the rejections of claims 1-10 and 15-20 under 35
U.S.C. § 103(a) as obvious over Dahlberg in view of Yogev; claim 21 under
35 U.S.C. § 103(a) as obvious over Dahlberg in view of Winston; and claim
9 under 35 U.S.C. § 103(a) as being obvious over Dahlberg in view of
Yogev and in further view of Aguilera.
We AFFIRM the rejections of claims 11-13 under 35 U.S.C. § 103(a)
as obvious over Dahlberg in view of Yogev; and claim 14 under 35 U.S.C.
§ 103(a) as being obvious over Dahlberg in view of Yogev and further in
view of Yoda.

No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C.F.R. § 1.136(a)(1).
AFFIRMED-IN-PART
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