Home Depot U.s.a., Inc. v. Lynk Labs, Inc.

N OTE: This disposition is nonprecedential.
United States Court of Appeals
for the Federal Circuit
______________________
HOME DEPOT U.S.A., INC.,
Appellant
v.
LYNK LABS, INC.,
Appellee
______________________
2023-2151
______________________
Appeal from the United States Patent and Trademark
Office, Patent Trial and Appeal Board in No. IPR2022-
00023.
______________________
Decided: March 14, 2025
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J ENNIFER L IBRACH N ALL , DLA Piper US LLP, Austin,
TX, argued for appellant. Also represented by BRIAN K.
ERICKSON; BENJAMIN SHAFER M UELLER , Chicago, IL;
STANLEY J OSEPH P ANIKOWSKI, III, San Diego, CA;
N ICHOLAS G. P APASTAVROS , Boston, MA.
STEPHEN T ERRY SCHREINER , Carmichael Ip, Tysons,
VA, argued for appellee. Also represented by J AMES
CARMICHAEL , STEPHEN MCBRIDE, MINGHUI YANG.
______________________
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HOME DEPOT U. S. A., INC. v. LYNK LABS, INC. 2
Before D YK, P ROST , and HUGHES , Circuit Judges.
D YK, Circuit Judge.
Home Depot U.S.A., Inc. (“Home Depot”) petitioned the
Patent Trial and Appeal Board (“Board”) for inter partes
review (“IPR”) of claims 1, 2, and 4 of U.S. Patent
No. 10,517,149 (the “’149 patent”). The Board instituted
IPR as to all challenged claims. In a final written decision,
the Board found Home Depot had shown claims 1 and 4
were unpatentable but had failed to show claim 2 was un-
patentable. Home Depot appeals the Board’s decision as to
claim 2. We reverse.
BACKGROUND
Lynk Labs, Inc. (“Lynk”) owns the ’149 patent, which is
titled “AC Light Emitting Diode and AC LED Drive Meth-
ods and Apparatus.” The ’149 patent states it “is directed
to an LED light emitting device and LED light system ca-
pable of operating during both the positive and negative
phase of an AC power supply.” ’149 patent, col. 12 ll. 36–
38. Specifically, the ’149 patent discloses a driver that is
configured to receive an AC voltage from a “mains power
source” (for example, the voltage emitted from a standard
wall outlet in the United States) and to provide a voltage
and current to an LED circuit. See ’149 patent, claim 1.
Claim 2, which depends from claim 1, is the only claim
at issue in this appeal. Together, claims 1 and 2 recite:
1. A lighting system comprising:
at least one LED circuit having a plurality
of LEDs, wherein the plurality of LEDs in-
cludes same or different colored LEDs;
a driver, wherein the driver includes at
least one transistor and at least one capac-
itor; and
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HOME DEPOT U. S. A., INC. v. LYNK LABS, INC. 3
a package, wherein the package is a heat
sinking reflective material;
the driver and the at least one LED circuit
all mounted on the package; and
the driver is configured to receive an AC
voltage from a mains power source and pro-
vide a voltage and current to the at least
one LED circuit.
2. The lighting system of claim 1, wherein the
driver is configured to receive at least two different
AC forward voltages.
’149 patent, claims 1–2.
In October 2021, Home Depot filed an IPR petition,
challenging claims 1, 2, and 4 of the ’149 patent as obvious
over U.S. Patent No. 5,457,450 (“Deese”) in view of other
references.1 The Board instituted IPR and ultimately con-
cluded that Home Depot had met its burden to prove un-
patentability as to claims 1 and 4 but had failed to meet its
burden as to claim 2. J.A. 53. Lynk does not challenge the
Board’s determinations as to claims 1 or 4. The dispute on
appeal is only as to claim 2 and whether the Board erred in
finding that the Deese prior art reference does not disclose
“wherein the driver is configured to receive at least two dif-
ferent AC forward voltages.”
1 Home Depot argued claims 1 and 2 were unpatent-
able as obvious over a combination of Deese, U.S. Patent
No. 6,019,493 (“Kuo”), and U.S. Patent No. 5,785,418
(“Hochstein”). Home Depot argued claim 4 was unpatent-
able over Deese, Kuo, Hochstein, and U.S. Patent
No. 5,014,052 (“Obeck”).
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HOME DEPOT U. S. A., INC. v. LYNK LABS, INC. 4
Deese discloses an LED traffic signal light with numer-
ous LED arrays connected in series. The total number of
LED arrays in Deese’s circuit is greater than necessary to
provide the appropriate amount of light to control traffic in
normal conditions. The excess LED arrays “provide for am-
ple light output during periods of reduced line voltage such
as is encountered during brown-out conditions.” J.A. 1268,
col. 5 ll. 31–35.
Figure 4 is illustrative:
J.A. 1254. Deese discloses that its “driver”2 receives, at
power line 118, voltages in three different ranges:
[T]he LED circuit 20 operates in one of three differ-
ent modes, depending on the voltage differential
provided across the line voltage power signal 118
2 The Board found Deese describes a “driver” that
“includes at least one transistor and at least one capacitor”
and “is configured to receive an AC voltage from a mains
power source and provide a voltage and current to the at
least one LED circuit,” as required by claim 1; Lynk does
not challenge this finding on appeal.
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HOME DEPOT U. S. A., INC. v. LYNK LABS, INC. 5
and the line voltage return signal 120. This volt-
age has a normal value of 120 volts AC. However,
for various reasons, this voltage can drop well be-
low this normal value. Embodiments of the present
invention preferably divide the possible values for
input power into three different voltage ranges, a
low voltage range, an intermediate voltage range
and a full voltage range.
J.A. 1269, col. 8 ll. 18–36. When the input voltage is inter-
mediate or low, Deese describes electrically disconnecting
a subset of the LED arrays from the traffic light circuit. By
removing a subset of LED arrays based on the level of volt-
age received, Deese effectively reduces the minimum volt-
age required to turn on the LED configuration and
maintain the light output of the traffic signal light at a suit-
able intensity utilizing the remaining LED arrays. See
J.A. 1270, col. 9 ll. 30–35.
Deese’s three modes of operation each correspond to
one of the three input voltage ranges: (1) in the full voltage
mode LED arrays 1–12, i.e., all arrays in LED configura-
tion 88, are illuminated; (2) in the intermediate voltage
mode only LED arrays 1–11 are illuminated; and (3) in the
low voltage mode only LED arrays 1–10 are illuminated.
J.A. 1269–70, col. 8 l. 37–col. 9 l. 20. The Board found that
Deese thus teaches “turn[ing] off power to LED arrays 12
and/or 11[,] . . . thereby affect[ing] the voltage drop across
the individual LEDs and the current provided to the indi-
vidual LEDs.” J.A. 32. Such functionality ensures that,
even in times of reduced line voltage such as a brownout,
the received voltage is at least the minimum sufficient to
allow current to flow through the connected LEDs arrays,
thereby illuminating them.
Important to this appeal is the meaning of the term
“forward voltages” as used in claim 2 of the ’149 patent.
Home Depot argued that the Board should construe the
term “forward voltage” as “the minimum voltage difference
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HOME DEPOT U. S. A., INC. v. LYNK LABS, INC. 6
required between the anode and cathode of the LEDs to al-
low current to flow through the LEDs,” i.e., the minimum
voltage required to turn on the LEDs. J.A. 129. Lynk ar-
gued no construction was required because “[one of ordi-
nary skill in the art] would readily understand the plain
and ordinary meaning of the claim language, which is that
the driver is configured to ‘receive an AC voltage from a
mains power source.’” J.A. 286. The Board adopted Home
Depot’s construction. The Board explained that the
’149 patent specification treated “forward voltage” and “AC
mains voltage” as distinct terms that cannot be equated
and that Lynk’s construction erroneously conflated the two
terms.
The Board then determined that Home Depot had not
established that Deese discloses a driver “configured to re-
ceive at least two different AC forward voltages” as con-
strued. The Board explained that “[w]hatever the value of
the AC mains voltage received at lines 118/120 in Deese,
that voltage is still AC mains voltage” and that “[w]hile the
forward voltage in the array may vary if the value of AC
mains voltage varies, neither [Home Depot] nor [its expert]
explain how the forward voltage of the LED array is re-
ceived by the driver.” J.A. 50. The Board thus concluded
Home Depot had not established that claim 2 was un-
patentable.
D ISCUSSION
Obviousness is a mixed question of fact and law. Apple
Inc. v. Gesture Tech. Partners, LLC, 127 F.4th 364, 368
(Fed. Cir. 2025). We review the Board’s legal conclusion of
obviousness de novo and its factual findings for substantial
evidence. Id. We interpret claim terms by looking to their
ordinary meaning in light of the specification and prosecu-
tion history. Id.; Phillips v. AWH Corp., 415 F.3d 1303,
1315–17 (Fed. Cir. 2005) (en banc).
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HOME DEPOT U. S. A., INC. v. LYNK LABS, INC. 7
I
As an initial matter, it is necessary to understand the
scope of the Board’s construction. First, under the Board’s
construction of “forward voltage,” the forward voltage is a
property of the LED circuit—i.e., it is the “minimum volt-
age difference required between the anode and cathode of
the LEDs to allow current to flow through the LEDs” of
that particular circuit. J.A. 18. For the claimed driver to
be configured to receive “at least two AC forward voltages,”
the driver must thus be configured to receive at least two
distinct “minimum voltages,” each of which is associated
with a respective LED circuit.
Second, contrary to Lynk’s assertions, nothing in the
claim limits the driver to being configured to receive only
the exact, “single value” forward voltage. Claim 2, by na-
ture of its dependence from claim 1, is a “comprising” claim
and so is presumptively open-ended. Gillette Co. v. Ener-
gizer Holdings, Inc., 405 F.3d 1367, 1371 (Fed. Cir. 2005).
Here, the open-ended “comprising” language means that
the claimed driver may also receive other voltages in addi-
tion to the exact forward voltage. This makes sense in
practice because, in order to power an LED circuit, a driver
may receive voltage beyond the exact minimum voltage
that allows current to flow through the LEDs. In other
words, if a driver receives voltage in excess of the forward
voltage, the driver has still received the forward voltage—
it has simply received excess voltage as well.
II
The undisputed facts show that Deese discloses “the
driver is configured to receive at least two different AC for-
ward voltages,” as required by claim 2. The Board’s con-
clusion to the contrary is unsupported by substantial
evidence.
Deese discloses three different LED circuit configura-
tions, each with a different forward voltage—that is, three
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HOME DEPOT U. S. A., INC. v. LYNK LABS, INC. 8
minimum voltages to power three different configurations.
Deese describes three modes of operation: (1) a full voltage
mode with LED arrays 1–12; (2) an intermediate voltage
mode with LED arrays 1–11; and (3) a low voltage mode
with LED arrays 1–10. J.A. 1269–70, col. 8 l. 37–col. 9
l. 20. Deese’s operating mode is determined by the voltage
that its “driver” receives (for example, the voltage input at
power line 118). Deese’s driver is configured to receive
three different voltage ranges corresponding to the three
operating modes. J.A. 1269, col. 8 ll. 18–36. In one embod-
iment, Deese describes that if the input voltage is greater
than 107 V, the system operates in the full voltage mode,
and its “LED circuit” comprises LED arrays 1–12. The for-
ward voltage of that configuration is the “minimum voltage
difference required between the anode and cathode of the
LEDs to allow current to flow through [LED arrays 1–12].”
If Deese’s driver receives a voltage between 96 V and 107 V
(for example, during a power grid brown out), the system
operates in the intermediate voltage mode, and electrically
disconnects LED array 12 from the circuit. The forward
voltage of that configuration is the “minimum voltage dif-
ference required between the anode and cathode of the
LEDs to allow current to flow through [LED arrays 1–11].”
Likewise, the forward voltage of Deese’s low voltage config-
uration is the minimum voltage to allow current to flow
through LED arrays 1–10.
Removing LED arrays 11 and/or 12 lowers the mini-
mum voltage required to turn on the circuit. As Lynk’s ex-
pert explained, a skilled artisan “would understand that
more LED arrays require more forward voltage,” J.A. 2079
(74:9–14)—in other words, the minimum voltage required
to allow current to flow through twelve series-connected
LED arrays is higher than the minimum voltage required
to allow current to flow through only eleven of the same
series-connected LED arrays. The Board accordingly
acknowledged that, in Deese, “the forward voltage in the
array may vary if the value of AC mains voltage [(for
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HOME DEPOT U. S. A., INC. v. LYNK LABS, INC. 9
example, the voltage at power line 118)] varies.” See
J.A. 50. By removing one or more of the series-connected
LED arrays based on the input voltage received, Deese
changes the forward voltage of the circuit to correlate to the
reduced input voltage. This functionality ensures that
there is enough voltage to allow current to flow through the
LED configuration, thereby keeping the connected LED ar-
rays illuminated in their respective operating modes.
Deese thus describes three different LED circuit configura-
tions with three different forward voltages.
It is also undisputed that Deese teaches a driver con-
figured to receive three different voltage ranges corre-
sponding to the three different LED circuit configurations.
Lynk admits that “Deese teaches an LED circuit having a
‘driver’ that receives an AC voltage input from [an AC
mains voltage source].” Appellee’s Br. 14. The Board
found, and Lynk does not dispute, that Deese’s “driver” re-
ceives three different voltages from a mains power source
via power line 118 and provides power to Deese’s twelve
LED arrays. As Lynk further acknowledges, Deese de-
scribes comparing the voltage input at the driver (i.e., the
voltage at line 118) to two threshold values (i.e., an inter-
mediate voltage threshold and a low voltage threshold) and
“if the input voltage is less than either threshold, then . . .
remov[ing] [LEDs] from the LED array.” Appellee’s Br. 29.
Deese thus describes a driver configured to receive at least
a first voltage when the power grid is operating in the full
voltage mode; a second, intermediate voltage when the
power grid is operating in the intermediate voltage mode;
and a third low voltage when the power grid is operating in
the low voltage mode. See, e.g., J.A. 1269, col. 7 ll. 24–33.
Each of these voltages is within the range sufficient to illu-
minate the LED arrays of the associated operating mode.
Accordingly, Deese’s driver is configured to receive at least
three different forward voltages, though the driver may
also receive voltages in excess of the minimum voltage re-
quired to turn on the LEDs. Since claim 2 is an open-ended
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HOME DEPOT U. S. A., INC. v. LYNK LABS, INC. 10
“comprising” claim, the fact that the driver may receive
other voltages is irrelevant.
Based on the undisputed facts, we conclude that Deese
teaches that its driver is “configured to receive at least two
different AC forward voltages.” Accordingly, Deese dis-
closes the claim limitation at issue. The Board’s conclusion
to the contrary is not supported by substantial evidence.
CONCLUSION
Because the undisputed facts show claim 2 is unpatent-
able under the proper claim construction, we reverse the
Board’s decision as to claim 2.
REVERSED
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