Ex Parte Sharps

Patent Trial and Appeal Board

May 26, 2016

12768457 (P.T.A.B. May. 26, 2016)

UNITED STA TES p A TENT AND TRADEMARK OFFICE
APPLICATION NO. FILING DATE
121768,457 04/27/2010
128940 7590 05/26/2016
SolAero Technologies Corp.
10420 Research Road SE
Albuquerque, NM 87123
FIRST NAMED INVENTOR
Paul R. Sharps
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
ATTORNEY DOCKET NO. CONFIRMATION NO.
6002B/6009-137 5646
EXAMINER
DAM, DUSTIN Q
ART UNIT PAPER NUMBER
1758
MAILDATE DELIVERY MODE
05/26/2016 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 PATENT TRIAL AND APPEAL BOARD
Exparte PAUL R. SHARPS 1
Appeal2014-007719
Application 12/768,457
Technology Center 1700
Before PETER F. KRATZ, BEYERL YA. FRANKLIN and
MICHAEL P. COLAIANNI, Administrative Patent Judges.
COLAIANNI, Administrative Patent Judge.
DECISION ON APPEAL
Appellant appeals under 35 U.S.C. § 134 the final rejection of claims
1-13 and 16-21. We have jurisdiction over the appeal pursuant to 35 U.S.C.
§ 6(b ).
We AFFIRM.
1 Appellant identifies the real party in interest as "Emcore Solar Power, Inc."
(Appeal Brief filed December 17, 2013 ("App. Br.") 1).
Appeal2014-007719
Application 12/768,457
Appellant's invention relates to solar cell semiconductor devices,
particularly, integrated semiconductor devices including a multijunction
solar cell and an integral bypass diode (Spec. 1, i-f2).
Claims 1 and 19-21 are independent. Claim 1 is illustrative (emphasis
added.)
1. An integral semiconductor body having a sequence of layers of
semiconductor material comprising:
a first region in which the sequence of layers of semiconductor
material forms at least one cell of a multijunction solar cell including
a metamorphic layer composed of InGaAlAs with a graded lattice
constant and having a constant 1. 5 e V bandgap throughout the layer
disposed between two subcells that are lattice mismatched with
respect to each other;
and a second region, spaced apart from said first region, in
which the sequence of layers in said second region forms a support for
a bypass diode that functions to pass current when the solar cell is
shaded.
(Claims App'x of Appeal Br. Cl-C5)
Appellant appeals the following rejections to the appealed claims as
unpatentable under 35 U.S.C. § 103:
2
Appeal2014-007719
Application 12/768,457
T l"i1 • -1 -1 A. -1 I"\. -1 ,.... 1 -1 / I"\. -1 , , 1 1 "TT T 1 ') •
L lAanns 1-lu, lL, u ana 10-Ll as unpatentao1e over wamass~ m
view of Sharps3 and of King4 (Final Rejection dated October 2, 2013
("Final Rej.") 3-20).
II. Claim 11 as unpatentable under 35 U.S.C. § 103(a) over Wanlass
in view ofHo5 (Final Rej. 20-21).
Appellant focused the arguments on the independent claims (App. Br.
5-11 ). Any claims not argued separately with regard to Rejections I and II
will stand or fall with our analysis regarding the present independent claims.
FINDINGS OF FACT & ANALYSIS
REJECTION (I): Claims 1-10, 12, 13 and 16-21.
The Examiner finds that Wanlass discloses all the limitations of claim
1 except for the semiconductor material having a sequence of layers in a
second region forming support for a bypass diode and a metamorphic layer
having a graded lattice constant composed of InGaAlAs (free from
phosphorus6) that has a constant band gap of 1.5 e V throughout the layer
(Final Rej. 3-4). The Examiner finds, however, that Sharps teaches adding a
second region to a multi-junction solar cell as support for a bypass diode to
2 U.S. 2006/0144435 Al to Wanlass et al., published July 6, 2006.
3 U.S. 2004/0163698 Alto Sharps et al., published August 26, 2004.
4 U.S. 2005/0274411 Al to King et al., published December 15, 2005.
5 U.S. 2005/0183765 Al to Ho et al., published August 25, 2005.
6 The Examiner found Wanlass disclosing its device having a buffer layer
composed of AlGainAsP, which is the same composition recited in claim 1
for the metamorphic layer but further containing phosphorus (see, e.g.,
Examiner's Answer dated May 7, 2014 ("Ans.") 24).
3
Appeal2014-007719
Application 12/768,457
allow current to pass when the solar cell is shaded to prevent reverse bias
causing damage to the cell. (Final Rej. 4). The Examiner concludes that it
would have been obvious to combine Wanlass' tandem solar cell with
Sharps' solar cell having a bypass diode because, inter alia, the bypass diode
would protect Wanlass' device against reverse biasing which could render
the cell inoperable (Final Rej. 4-5).
The Examiner finds King disclosing a transparent graded
metamorphic layer (AlGainAs) to lattice match deposited cell layers and that
King also suggests choosing optimal bandgap values for the buffer layer to
improve performance of the solar cells (Final Rej. 5). The Examiner
concludes that it would have been obvious to replace Wanlass' graded
metamorphic layer (AlGainAsP) with King's graded metamorphic layer
(AlGainAs) because it would lead to minimizing internal stresses and strains
(Final Rej. 5-6). The Examiner further finds that one in the art would be
motivated to optimize the bandgap of the metamorphic graded layer to arrive
at a claimed range of a constant 1.5e V through the buffer layer through
routine experimentation (Final Rej. 6; King, i-f20).
Appellant contends that although Sharps discloses a multijunction
solar cell having a bypass diode, it would not have been obvious to modify
Wanlass' particular multi-junction solar cell to include a bypass diode
because the latter contains a metamorphic or grading interlayer (App. Br. 6).
Appellant contends that the Examiner failed to establish that one skilled in
the art would obtain predictable results by including Sharps' bypass diode in
Wanlass' multi-junction device having a grading/metamorphic layer due to
the two references having varying approaches to lattice matching issues
(App. Br. 6-7). Appellant further relies on the background discussion in the
4
Appeal2014-007719
Application 12/768,457
Specification as support for the unpredictability of combining a bypass diode
with a multi-junctional solar cell having a metamorphic/graded layer. (Reply
Brief entered July 7, 2014 ("Reply Br.") 1-5).
Appellant further contends that King does not suggest its
metamorphic layer (InGaAlAs) having a constant bandgap of 1.5 eV and
relies on the Sharps Declaration 7 to show unexpected results to overcome
this obviousness rejection using experimental data comparing a grading
interlayer ofinGaAlAs having a constant bandgap of 1.5 eV and a layer of
GainAs having a varying bandgap (App. Br. 7-12; Reply Br. 5-6).
The Examiner responds that an ordinarily skilled artisan using a
bypass diode in Wanlass' multijunction solar cell possessing a metamorphic
layer would have had a reasonable expectation of success (predictable result)
in view of Sharps' teachings regarding the benefit of a bypass diode
protecting a cell from reverse biasing during times of shadow or low sun
light (Ans. 22). The Examiner further responds that this teaching is not
limited to solar cells without a metamorphic layer but that the benefit of
including a bypass diode is applicable to solar cells in general (Ans. 22).
The Examiner further responds that Sharps and Wanlass both address the
issue of increasing cell efficiency and are concerned with the identical
problem of matching (or mismatching) lattice constants between adjacent
layers to increase efficiency (Ans. 22-23)
The Examiner further responds that the Sharps Declaration depicts
results from comparative studies between the claimed InGaAlAs layer and
an InGaAs layer but does not provide any data of improved performance
7 Declaration by Paul Sharps (Inventor) filed November 8, 2012 (hereinafter
"Sharps Declaration").
5
Appeal2014-007719
Application 12/768,457
between the claimed metamorphic layer and AlGainAsP, which is the
metamorphic layer disclosed in Wanlass (the primary reference in the
rejections) (Ans. 24). The Examiner also responds that King expressly
discloses that the solar cell voltage is approximately linearly dependent on
the band gap of the semiconductor material and, thus, is teaching that the
bandgap for the metamorphic layer is a result effective variable (Ans. 25;
King, if20).
We have fully considered Appellant's arguments and we find that the
preponderance of the evidence favors the Examiner's conclusion of
obviousness. Contrary to Appellant's contentions, we are in agreement with
the Examiner that a person skilled in the art would have understood from the
teachings in Wanlass and Sharps that it would have been obvious to include
a bypass diode region in Wanlass' multijunction solar cell having a
metamorphic/grading layer to reduce reverse biasing (Ans. 4 and 22-24).
We further agree with the Examiner that in view of Wanlass' and King's
teachings, the ordinary artisan would have appreciated that the bandgap is a
result effective variable and would have routinely optimized the
metamorphic layer in the prior art to have a constant bandgap of 1.5 e V
(Ans. 5 and 25).
Particularly, we find Appellant's arguments with respect to the lack of
predictable results resulting from including a bypass diode in a multijunction
solar cell having a metamorphic layer as unpersuasive. We agree with the
Examiner that Wanlass and Sharps are both drawn to enhancing the
efficiency of cells by lattice matching/mismatching and that, in view of the
general teachings in Sharps, it would have been obvious to one in the art to
6
Appeal2014-007719
Application 12/768,457
add a bypass diode region to Wanlass' device to stop current from reversing
during shading (Ans. 22-23).
Moreover, we are not persuaded by Appellant's reliance on the
background section of the present Specification as showing that the
"materials and fabrication steps for preparing a solar cell having an inverted
metamorphic structure with an integral bypass diode have neither been
disclosed nor suggested" (Reply Br. 1-4; Spec. i-fi-16-12). To the contrary, the
first document disclosed by Appellant in the portion of the Specification
relied upon as evidence of the lack of suggestion for including a bypass
diode in a multi-junction cell having a metamorphic or graded layer is Iles
(U.S. 6,951,819) (Reply Br. 3; Spec. i-f 12). Iles, however, discloses
including a bypass diode in a reverse (inverted) multijunction solar cell
structure having buffer/lattice grading layers (Iles, col. 3, 1. 62 to col. 4, 1. 2;
col. 6, 11. 31-48; col. 8, 1. 65 to col. 9, 1. 6; Figure 6). Consequently, as
evidenced by Iles, the prior art cited by Appellant discloses and would have
suggested including a bypass diode in an inverted multijunction solar cells
having buffer/ graded layers.
We are also unpersuaded by Appellant's arguments traversing the
Examiner's findings of the bandgap value for the metamorphic layer as a
result effective variable and that one in the art would have optimized the
bandgap by routine experimentation to attain a constant bandgap of 1.5 e V
(App. Br. 10-11). As found by the Examiner, King teaches in paragraph 20
the advantages of using a graded layer to lattice match deposited cells to
minimize stresses/strains and that optimal bandgaps are chosen for the buffer
layer that would improve the cell's performance (Ans. 4-5; King, i-fi-120, 43).
The subsequent paragraph in King describes suitable embodiments
7
Appeal2014-007719
Application 12/768,457
employing a graded layer including a transparent buffer layer of AlGainAs,
which would have reasonably been understood from King's disclosure as
possessing and imparting the desired properties to the solar cell (King, i-f2 l ).
Furthermore, contrary to Appellant's position, Wanlass discloses that exact
bandgap values for solar cells and various layers in between the solar cells in
a multijunction solar cell can be the product of computer calculations and
empirical optimization (Wanlass, i-fi-135, 38, 39, 62 and 66). Consequently,
one in the art, in view of the combined teachings of Wanlass and King,
would have routinely optimized the bandgap of the metamorphic/graded
layer to, for example, a constant value of 1.5 e V.
With respect to the experimental data submitted in the Sharps
Declaration, we are unpersuaded by the results therein because the
comparative data does not address the Examiner's obviousness rejections
based upon Wanlass as the primary reference, which discloses its
metamorphic layer composed of AlGainAsP. We agree with the Examiner,
that the experimental data comparing the claimed metamorphic layer
(AlGainAs) with a ternary metamorphic layer (InGaAs) is not a showing of
unexpected results that overcomes this rejection because the Appellant fails
to provide data comparing Wanlass' metamorphic layer (i.e., the closest
prior art) to that recited in the present independent claims. Therefore, the
comparative data in the Sharps Declaration fails to compare the claimed
invention with the closest prior art. In re Burckel, 592 F .2d 117 5 ( CCP A
1979).
Accordingly, we affirm the Examiner's rejection of claims 1-10, 12,
13 and 16-21under35 U.S.C. § 103(a) as unpatentable over Wanlass,
Sharps and King.
8
Appeal2014-007719
Application 12/768,457
REJECTIONS (II): Claim 11.
Appellant submits that the deficiencies of Wanlass as applied to claim
11 are the same or similar to the deficiencies of Wanlass as applied in
Rejection I and that Ho does not provide that which is missing from
Wanlass.
However, as discussed previously, Appellant's arguments traversing
the Examiner's findings in Rejection I have been deemed unavailing.
Thus, based on this record, we sustain these rejections.
CONCLUSION
Accordingly, on this record and for the above reasons, we sustain the
35 U.S.C. §103 Rejections (I-II) of the claims 1-13 and 16-21 over the cited
prior art.
DECISION
The Examiner's § 103 rejections are affirmed.
No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C.F.R. § 1.136(a).
AFFIRMED
9