LG Display Co., Ltd.

Patent Trials and Appeals Board

Jun 15, 2020

2019004267 (P.T.A.B. Jun. 15, 2020)

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.
15/198,640 06/30/2016 Byungsoo Kim 002463-5151 3372
9629 7590 06/15/2020
Morgan, Lewis & Bockius LLP (WA)
1111 Pennsylvania Avenue, N.W.
Washington, DC 20004
EXAMINER
TRAN, DZUNG
ART UNIT PAPER NUMBER
2829
NOTIFICATION DATE DELIVERY MODE
06/15/2020 ELECTRONIC
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.
Notice of the Office communication was sent electronically on above-indicated "Notification Date" to the
following e-mail address(es):
karen.catalano@morganlewis.com
patents@morganlewis.com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL AND APPEAL BOARD
Ex parte BYUNGSOO KIM
Appeal 2019-004267
Application 15/198,640
Technology Center 2800
Before LINDA M. GAUDETTE, JAMES C. HOUSEL, and
BRIAN D. RANGE, Administrative Patent Judges.
HOUSEL, Administrative Patent Judge.
DECISION ON APPEAL
STATEMENT OF THE CASE1
Pursuant to 35 U.S.C. § 134(a), Appellant2 appeals from the
Examiner’s decision to reject claims 1, 2, 4–14, and 21–26 under 35 U.S.C.
§ 103 as unpatentable over Weaver (US 2013/0320837 A1, pub. Dec. 05,

1 This Decision refers to the Specification (“Spec.”) filed June 30, 2016, the
Non-Final Office Action (“Non-Final Act.”) dated May 2, 2018, the Appeal
Brief (“Appeal Br.”) filed December 14, 2018, the Examiner’s Answer
(“Ans.”) dated March 8, 2019, and the Reply Brief (“Reply Br.”) filed May
8, 2019.
2 We use the word Appellant to refer to “applicant” as defined in 37 C.F.R.
§ 1.42(a). Appellant identifies the real party in interest as LG Display Co.,
Ltd. Appeal Br. 3.
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2013) in view of Lee (US 2007/0164278 A1, pub. July 19, 2007). We have
jurisdiction under 35 U.S.C. § 6(b).
We AFFIRM.
CLAIMED SUBJECT MATTER
The invention relates to an organic light emitting device having a
structure with a plurality of light emitting units having a combination of
dopant materials that reduce color shift caused by variation of viewing
angle. Spec. ¶ 2. The plurality of light emitting units may include dopant
materials emitting light of different wavelengths such that variation of color
and luminance, which a user perceives as viewing angle varies, is reduced.
Id. ¶ 16. The light emitting units may emit red, green, or blue light, and color
shift caused by variation of viewing angle of white emitted light obtained by
a mixture of red, green, and blue emitted light from red, green, and blue
organic light emitting devices is minimized. Id.
In order to accomplish this objective, Appellant discloses selecting
different dopant materials for the plurality of light emitting units of the
organic light emitting device such that a photoluminance (“PL”) peak of one
dopant (“main dopant”) in one of the light emitting units is within the range
of 0–15 nm of a PL peak of a second dopant (“auxiliary dopant”) in a second
one of the light emitting units. Spec. ¶ 67. In addition, the PL peak of the
auxiliary dopant is biased towards a shorter wavelength as compared to the
PL peak of the main dopant. Id. The main and auxiliary dopants may be
selected such that the out-coupling emittance spectrum curve overlaps with
or is closer to the PL peak of the main dopant when the viewing angle is 0˚
(i.e., in the front direction) and overlaps with or is closer to the PL peak of
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the auxiliary dopant at a wide viewing angle in a lateral or side direction. Id.
¶¶ 68–69.
Claims 1 and 21, reproduced below from the Claims Appendix to the
Appeal Brief, are illustrative of the claimed subject matter:
1. An organic light emitting device, comprising:
an anode and a cathode, which are spaced apart from
each other to face each other; and
a first light emitting unit including a first organic light
emitting layer, a charge generating layer, and a second light
emitting unit including a second organic light emitting layer,
which are between the anode and the cathode,
wherein a main dopant material is doped on any one of
the first organic light emitting layer and the second organic
light emitting layer, and an auxiliary dopant material emitting
the same colored light as that of the main dopant material is
doped on the other one among the first organic light emitting
layer or the second organic light emitting layer having the main
dopant material doped thereon, and
a photoluminescence (PL) peak of the main dopant
material is in the range of 0nm to 15nm from a PL peak of the
auxiliary dopant material,
wherein the organic light emitting device emits any one
of blue light, green light, and red light, and
wherein a peak of an out-coupling emittance spectrum
curve at a viewing angle of 0° of the organic light emitting
device is closer to the PL peak of the main dopant material than
the PL peak of the auxiliary dopant material.

21. An organic light emitting device, comprising:
an anode and a cathode; and
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a first light emitting unit including a first organic light
emitting layer and a second light emitting unit including a
second organic light emitting layer, the first light emitting unit
between the anode and the cathode,
wherein the first organic light emitting layer and the
second organic light emitting layer include a main dopant
material and an auxiliary dopant material, and
wherein a photoluminescence (PL) peak of an out-
coupling emittance spectrum curve according to a viewing
angle is alternatively overlapped with a PL peak of the main
dopant material and a PL peak of the auxiliary dopant material,
and
wherein the organic light emitting device emits any one
of blue light, green light, and red light.

OPINION
We review the appealed rejection for error based upon the issues
Appellant identifies, and in light of the arguments and evidence produced
thereon. Ex parte Frye, 94 USPQ2d 1072, 1075 (BPAI 2010) (precedential)
(cited with approval in In re Jung, 637 F.3d 1356, 1365 (Fed. Cir. 2011)
(“[I]t has long been the Board’s practice to require an applicant to identify
the alleged error in the examiner’s rejections.”). After considering the
argued claims and each of Appellant’s arguments, we are not persuaded of
reversible error in the appealed rejection.
Appellant argues each of independent claims 1 and 21, as well as
dependent claim 4 separately, but does not present separate arguments for
the remaining dependent claims. In accordance with 37 C.F.R.
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§ 41.37(c)(1)(iv), claims 2, 5–14, and 22–26 stand or fall with their
respective independent claim.
Claim 1
The dispositive issue before us with regard to the obviousness
rejection of claim 1 is whether Appellant has identified reversible error in
the Examiner’s determination that the combination of Weaver and Lee
would have suggested the limitation “wherein a peak of an out-coupling
emittance spectrum curve at a viewing angle of 0° of the organic light
emitting device is closer to the PL peak of the main dopant material than the
PL peak of the auxiliary dopant material.” We answer this question in the
negative and, therefore, affirm the obviousness rejection of claim 1 for the
reasons given in the Non-Final Office Action and the Examiner’s Answer.
We add the following primarily for emphasis.
The Examiner finds that Weaver teaches an organic light emitting
device having first and second light emitting units disposed between an
anode and a cathode, wherein the units are doped with different dopant
materials of the same color, respectively, such that the PL peak of one
dopant material is at least 4 nm less than the PL peak of a second dopant
material. Non-Final Act. 3. Thus, the Examiner finds that Weaver teaches all
the features of claim 1 except that the organic light emitting device emits
any one of red, green, and blue light.3 Id. at 3–4. For this feature, the

3 The Examiner appears to be interpreting claim 1 as excluding an organic
light emitting device that emits more than one of red, green, and blue light.
However, we see no reason to read claim 1 so narrowly. Instead, we
interpret claim 1 to require that the device emits any one of red, green, and
blue light, but may emit any two or all three of these colors. This
interpretation is consistent with the Specification. See, e.g., Spec. ¶¶ 14, 16,
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Examiner finds that Lee teaches an organic light emitting device emitting
blue light. Id. at 4. The Examiner concludes it would have been obvious to
provide that Weaver’s organic light emitting device emit blue light in order
to provide the brightness and efficiency of the blue emission layers for
improving performance and power consumption, as Lee suggests. Id.
The Examiner acknowledges that the combination of Weaver and Lee
does not expressly disclose that the peak of an out-coupling emittance
spectrum curve at a viewing angle of 0° of the organic light emitting device
is closer to the PL peak of a main dopant material than the PL peak of an
auxiliary dopant material. Non-Final Act. 4. However, the Examiner
determines that this feature would have been obvious in Weaver’s device in
order to improve performance since the general conditions of claim 1 are
disclosed therein and discovering the optimum or workable ranges involves
only routine skill in the art. Id. at 4–5 (citing In re Aller, 220 F.2d 454, 456
(CCPA 1955)). In particular, the Examiner finds that, by selecting the
dopant materials, the peak of an out-coupling emission spectrum curve at a
viewing angle of 0° of Weaver’s device would be closer to the PL peak of
one of the dopants than of the other.
Appellant argues that the Examiner erred in concluding that the
limitation at issue, “wherein a peak of an out-coupling emittance spectrum
curve at a viewing angle of 0° of the organic light emitting device is closer
to the PL peak of the main dopant material than the PL peak of the auxiliary

26, 27, 29, 71–73, 81, 82, 92–95, 98, 99; Figs. 4A–4C, 5A–5C, 8, 9. Thus,
claim 1, when properly interpreted, encompasses a device such as Weaver’s
which emits red, green, and blue light that are combined to create white
light. As such, Lee is not necessary to maintain an obviousness rejection
against claim 1.
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dopant material,” would have been obvious over the combination of Weaver
and Lee. Appeal Br. 6–8. In particular, Appellant contends that the
Examiner’s rationale for this obviousness conclusion is based on
impermissible hindsight because this rationale is not disclosed in either
reference and is derived from Appellant’s Specification. Id. at 7–8.
Appellant’s argument is not persuasive of reversible error in the
Examiner’s rejection because the limitation at issue is dependent on
determining which of Weaver’s two dopant materials is the main dopant
material and which is the auxiliary dopant material. We begin, appropriately,
with the claim’s words. See Oakley, Inc. v. Sunglass Hut Int’l, 316 F.3d
1331, 1339 (Fed. Cir. 2003) (explaining that anticipation and obviousness
require comparison of the properly construed claims to the available prior
art); Amazon.com, Inc. v. Barnesandnoble.com, Inc., 239 F.3d 1343, 1351
(Fed. Cir. 2001) (“Only when a claim is properly understood can a
determination be made . . . whether the prior art anticipates and/or renders
obvious the claimed invention.”).
We note that claim 1 recites that the main dopant material may be in
either the first or the second organic light emitting layer, and the auxiliary
dopant material is in the other of these two layers. In addition, claim 1
recites that the main and auxiliary dopant materials emit the same colored
light and have PL peaks within 0–15 nm of each other. Other than the
limitation at issue, claim 1 does not otherwise define or distinguish the main
and auxiliary dopant materials. The Specification similarly does not define
nor distinguish the main and auxiliary dopants other than to disclose that the
auxiliary dopant material has a shorter wavelength than the main dopant
material. Spec. ¶ 67. In re ICON Health & Fitness, Inc., 496 F.3d 1374,
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1379 (Fed. Cir. 2007) (“[T]he PTO must give claims their broadest
reasonable construction consistent with the specification . . . Therefore, we
look to the specification to see if it provides a definition for claim terms, but
otherwise apply a broad interpretation.”). However, the Specification does
not define or otherwise require that the auxiliary dopant material has the
shorter wavelength emission. As such, claim 1 does not require that the
auxiliary dopant has the shorter wavelength emission. In re Van Geuns, 988
F.2d 1181, 1184 (Fed. Cir. 1993) (“[L]imitations are not to be read into the
claims from the specification.”).
There is no dispute that Weaver teaches two dopant materials emitting
the same colored light, each disposed in a different one of first and second
organic light emitting layers, wherein the PL peak of one dopant material is
at least 4 nm less than the PL peak of the other dopant material. However,
because claim 1 does not specify which of the main and auxiliary dopant
materials has the shorter wavelength emission, the main dopant material and
the auxiliary dopant material read on either of Weaver’s dopant materials.
This interpretation is significant considering that the issue before us depends
on which of Weaver’s two dopant materials is the main dopant material and
which is the auxiliary dopant material because claim 1 recites that the out-
coupling emittance spectrum curve at a 0° viewing angle is closer to the PL
peak of the main dopant material than the PL peak of the auxiliary dopant
material. Accordingly, claim 1’s main dopant material reads on whichever of
Weaver’s two dopant materials has a PL peak closer to the out-coupling
emittance spectrum curve at a 0° viewing angle regardless of whether its PL
peak is shorter or longer than the other dopant material’s PL peak. As such,
Weaver meets the limitation at issue.
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Turning to the Examiner’s obviousness rationale for modifying
Weaver to provide the peak of the out-coupling emittance spectrum curve at
a 0° viewing angle that is closer to the PL peak of the main dopant material
than the PL peak of the auxiliary dopant material, the Examiner finds, and
Appellant does not dispute, that an ordinary artisan would have known that
each of these peaks is dependent on the dopant material properties. Ans. 4.
The Examiner determines that the ordinary artisan would have selected the
dopant materials so as to provide that the out-coupling emittance spectrum
curve peak is closer to the longer wavelength dopant than the shorter
wavelength dopant in order to improve the organic light emitting device
performance. Id. at 5. Such a determination is consistent with the fact that it
was known that perceived light emitted from an organic light emitting
device shifts to lower wavelengths as the viewing angle increases from a
front to a lateral direction. Therefore, the peak of the out-coupling emittance
spectrum curve also necessarily shifts to lower wavelengths with increasing
viewing angle. As such, the ordinary artisan would reasonably expect that
the organic light emitting device performance at a 0° viewing angle would
improve by ensuring that the out-coupling emittance spectrum curve peak
was closer to or even overlaps with the PL peak of the dopant material
having the longer wavelength emission. Therefore, the Examiner’s rationale
for modifying Weaver is based on Weaver and the inherent properties of
organic light emitting devices and their dopant materials, rather than
Appellant’s Specification.
Appellant does not otherwise challenge the Examiner’s rejection of
claim 1. Accordingly, we sustain the Examiner’s obviousness rejection of
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claim 1, and dependent claims 2, 5–14, and 26, over the combination of
Weaver and Lee.
Claim 21
The dispositive issue before us with regard to the obviousness
rejection of claim 21 is whether Appellant has identified reversible error in
the Examiner’s determination that the limitation “a photoluminescence (PL)
peak of an out-coupling emittance spectrum curve according to a viewing
angle is alternatively overlapped with a PL peak of the main dopant material
and a PL peak of the auxiliary dopant material” would have been obvious
over the combination of Weaver and Lee. We answer this question in the
negative and, therefore, affirm the obviousness rejection of claim 21 for the
reasons given in the Non-Final Office Action and the Examiner’s Answer.
We add the following primarily for emphasis.
The Examiner finds, in relevant part, that Weaver teaches the
limitation at issue. Non-Final Act. 5; Ans. 6. More specifically, the
Examiner finds that “the wavelength at which an organic emissive layer
emits light may generally be readily tuned with appropriate dopants,” i.e.,
the PL peak of an organic light emitting layer depends on the dopant
material. Ans. 7. Therefore, the Examiner finds that given Weaver’s two
dopant materials emitting the same colored light but at wavelengths
separated by at least 4 nm, Weaver inherently provides a PL peak of an out-
coupling emittance spectrum curve according to a viewing angle that
alternatively overlaps with the PL peak of the longer wavelength dopant
material and a PL peak of the shorter wavelength dopant material. Id.
Appellant argues that the Examiner has failed to establish that Weaver
inherently teaches the limitation at issue. Appeal Br. 10. Appellant contends
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that because the Examiner finds that the three peaks (the out-coupling
emittance spectrum curve peak, and the two PL peaks of the dopant
materials) depend on the material properties, the Examiner implicitly
acknowledges that Weaver fails to actually disclose materials that meet the
limitation at issue. Id.
Appellant’s arguments are not persuasive of reversible error because,
in our view, the Examiner has reasonably established that Weaver inherently
provides an organic light emitting device whose out-coupling emittance
spectrum curve peak alternatively overlaps the PL peaks of the two dopant
materials. Similar to claim 1, claim 21 does not require that the main dopant
material has a longer wavelength than the auxiliary dopant material, nor
does claim 21 limit which dopant is in each of the two organic light emitting
layers. Moreover, claim 21 does not specify that the layers are stacked one
upon the other, nor which layer is above the other in a light emitting
direction.
As indicated above, there is no dispute that Weaver teaches two
dopant materials emitting the same colored light, each disposed in a different
one of first and second organic light emitting layers, wherein the PL peak of
one dopant material is at least 4 nm less than the PL peak of the other dopant
material. Indeed, Weaver teaches that the longer wavelength dopant may be
in either of the first or the second of two stacked organic light emitting
layers. Weaver, Fig. 9. Appellant does not direct us to any difference in
structure or material between Weaver and claim 21, nor between Weaver
and the disclosed structure. Given that it was known that the perceived light
emitted from an organic light emitting device shifts to lower wavelengths as
the viewing angle increases from a front to a lateral direction, the peak of the
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out-coupling emittance spectrum curve also necessarily shifts to lower
wavelengths with increasing viewing angle. Therefore, Weaver’s two
organic light emitting units, which are structurally identical to that recited in
claim 21 and indistinguishable from Appellant’s disclosed structure, would
necessarily provide an out-coupling emittance spectrum curve peak that
alternately overlaps with each of the PL peaks of Weaver’s dopant materials.
Appellant does not otherwise challenge the Examiner’s rejection of
claim 21. Accordingly, we sustain the Examiner’s obviousness rejection of
claim 21, and dependent claims 22–25, over the combination of Weaver and
Lee.
Claim 4
Claim 4 depends from claim 1, and further requires that the out-
coupling emittance spectrum curve peak at a 60° viewing angle is closer to
the PL peak of the auxiliary dopant material that the PL peak of the main
dopant material.
The Examiner finds that the combination of Weaver and Lee fails to
explicitly disclose the limitation of claim 4. Non-Final Act. 7. However, the
Examiner determines that it would have been obvious to provide Weaver
with this feature as a matter of routine optimization in order to improve the
organic light emitting device’s performance. Id.
Appellant argues that the Examiner erred in concluding that the
limitation of claim 4 would have been obvious because the Examiner has
neither established that “general conditions” of this claim are disclosed in
the prior art nor that they are result-effective variables amenable to
optimization. Appeal Br. 10–11.
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In response, the Examiner finds, and Appellant does not dispute, that
an ordinary artisan would have known that each of these peaks is dependent
on the dopant material properties. Ans. 8. The Examiner determines that the
ordinary artisan would have selected the dopant materials so as to provide
that the out-coupling emittance spectrum curve peak is closer to the shorter
wavelength dopant than the longer wavelength dopant at a 60° viewing
angle in order to improve the organic light emitting device performance. Id.
As above, such a determination is consistent with the fact that it was known
that perceived light emitted from an organic light emitting device shifts to
lower wavelengths as the viewing angle increases from a front to a lateral
direction, the peak of the out-coupling emittance spectrum curve also
necessarily shifts to shorter wavelengths with increasing viewing angle. As
such, the ordinary artisan would reasonably expect that the organic light
emitting device performance at a 60° viewing angle would improve by
ensuring that the out-coupling emittance spectrum curve peak was closer to
with the PL peak of the dopant material having the shorter wavelength
emission. Therefore, Appellant has not shown error in the Examiner’s
determination that it would have been obvious to modify Weaver’s dopant
materials such that the out-coupling emittance spectrum curve peak is closer
to the PL peak of Weaver’s shorter wavelength dopant at a 60° viewing
angle.
Appellant does not otherwise challenge the Examiner’s rejection of
claim 4. Accordingly, we sustain the Examiner’s obviousness rejection of
claim 4 over the combination of Weaver and Lee.
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CONCLUSION
Upon consideration of the record, and for the reasons given above and
in the Non-Final Office Action and the Answer, the Examiner’s decision to
reject claims 1, 2, 4–14, and 21–26 under 35 U.S.C. § 103 as unpatentable
over Weaver in view of Lee is affirmed.
DECISION SUMMARY
In summary:
Claims
Rejected
35 U.S.C.
§
Reference(s)/Basis Affirmed Reversed
1, 2, 4–14,
21–26
103 Weaver, Lee 1, 2, 4–14,
21–26

TIME PERIOD FOR RESPONSE
No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C.F.R. § 1.136(a). See 37 C.F.R.
§ 1.136(a)(1)(iv).
AFFIRMED