United States Court of Appeals
for the Federal Circuit
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IN RE RAMBUS, INC.
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2013-1192
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Appeal from the United States Patent and Trademark
Office, Patent Trial and Appeal Board in Reexamination
Nos. 95/000,166 and 95/001,122.
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Decided: June 4, 2014
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JAMES R. BARNEY, Finnegan, Henderson, Farabow,
Garrett & Dunner, LLP, of Washington, DC, argued for
appellant. With him on the brief were J. MICHAEL JAKES,
MOLLY R. SILFEN, and AIDAN C. SKOYLES. Of counsel was
KATHLEEN DALEY.
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Before RADER, ∗ MOORE and REYNA, Circuit Judges.
REYNA, Circuit Judge.
This is an appeal from an inter partes reexamination
of claims 26 and 28 of U.S. Patent No. 6,426,916 (“the ’916
patent”). The Patent Trial and Appeal Board (“Board”) at
∗
Randall R. Rader vacated the position of Chief
Judge on May 30, 2014.
2 IN RE RAMBUS, INC.
the United States Patent and Trademark Office (“PTO”)
found that the claims were anticipated by U.S. Patent No.
4,734,909 to Bennett (“Bennett”). Patent owner Rambus,
Inc. (“Rambus”) appeals the Board’s anticipation decision,
arguing that Bennett does not disclose the claimed “value
that is representative of an amount of time to transpire
after which the memory device outputs the first amount of
data.”
After oral argument, requestor Micron Technology,
Inc. (“Micron”) moved to withdraw from this case, which
we granted in a separate order. Rambus has the right to
appeal the Board’s rejection of its claims irrespective of
Micron’s participation in this appeal. See 35 U.S.C. §
315(a)(1) (2006). Thus, despite Micron’s withdrawal, a
live controversy regarding the patentability of Rambus’s
claims remains before us for resolution. 1 We do not reach
Micron’s alternate grounds for affirming the Board,
because these arguments have been withdrawn. As
discussed below, we reverse the Board’s anticipation
decision as unsupported by substantial evidence.
BACKGROUND
The ’916 patent discloses a method and system for
improving the efficiency of computer memory. Broadly
speaking, a computer may need to transfer data between
different memory devices, such as between a memory
controller (sometimes called a master) and a memory
device that stores data (sometimes called a slave). This
data may be transferred via a “bus,” such as a series of
wires, or “lines,” that connect the memory device and the
controller. Some memory systems include a wait signal
that is sent, sometimes over a wait line, from a memory
device to a memory controller that says the memory
1 We note that the PTO does not seek to intervene
in this case.
IN RE RAMBUS, INC. 3
device is not ready to receive or send data. The wait
signal may also indicate when the memory device will be
ready to send data.
Relevant to this appeal, signals may be transferred
via a bus using either “dedicated” lines or “multiplexed”
lines. If a signal has a dedicated line on the bus it means
that this signal does not share its line with other signals.
This can be analogized to a multiple lane road where each
car (signal) has its own lane, which it can travel on at any
time without interfering with a car on another lane. By
contrast, two signals may be multiplexed on a single line.
For example, if a “wait” signal and a “data” signal are
time-division multiplexed, they share a single line on the
bus in a time based manner and cannot use the line at the
same time. This may be analogized to a one lane road
that cars cannot drive on at the same time.
If two memory devices want to use the bus at the
same time but, for technical reasons not relevant here,
they cannot, the process by which the computer chooses
which device goes first is called “arbitration.” A memory
device may be ready to send data to a memory controller
but, if it “loses” arbitration, it will have to wait until the
device that won arbitration has finished using the bus.
The ’916 patent attempts to improve this general
memory transfer system with the addition of two features:
(1) an external clock to synchronize the timing of the data
transfer and, (2) for a particular memory transfer request,
delaying the transfer by a specific, known amount of time.
For example, when a memory controller requests data
from a memory device, the controller will ask the memory
device to begin transferring the data after a certain
number of clock cycles (the specification refers to this as a
“delay”). Because the controller will know precisely when
the data will be transferred on the bus, it can be prepared
to receive it and can also use the bus during the delay to
perform other tasks.
4 IN RE RAMBUS, INC.
While there are two necessary features of the design
disclosed in the ’916 patent (the external clock and the
known delay time), only the delay time is at issue in this
appeal. With the relevant language emphasized, claim 26
recites:
A synchronous semiconductor memory device hav-
ing at least one memory section including a plu-
rality of memory cells, the memory device
comprising:
clock receiver circuitry to receive an external clock
signal;
first input receiver circuitry to sample block size
information synchronously with respect to the ex-
ternal clock signal, wherein the block size infor-
mation is representative of an amount of data to
be output by the memory device in response to a
first operation code;
a register which stores a value that is representa-
tive of an amount of time to transpire after which
the memory device outputs the first amount of da-
ta;
and a plurality of output drivers to output the
amount of data in response to the first operation
code and after the amount of time transpires.
(emphasis added). Claim 28 depends on 26 and recites:
The memory device of claim 26 wherein in re-
sponse to a second operation code, the value is
stored in the register.
The parties disputed before the PTO whether Bennett
discloses “a value that is representative of an amount of
time to transpire after which the memory device outputs
the first amount of data.” The examiner found this limi-
tation lacking in Bennett. The Board disagreed and found
that “Parameter VI” in Bennett discloses the claimed
IN RE RAMBUS, INC. 5
“value.” Because the Board’s conclusion is not supported
by substantial evidence, we reverse.
DISCUSSION
Claims are generally given their “broadest reasonable
interpretation” consistent with the specification during
reexamination. See, e.g., In re Yamamoto, 740 F.2d 1569
(Fed. Cir. 1984). This claim construction standard is
justified, at least in part, because a patentee is able to
amend its claims during reexamination. See, e.g., Exxon
Research & Eng'g Co. v. United States, 265 F.3d 1371,
1380 (Fed. Cir. 2001). If, as is the case here, a reexamina-
tion involves claims of an expired patent, a patentee is
unable to make claim amendments and the PTO applies
the claim construction principles outlined by this court in
Phillips v. AWH Corp., 415 F.3d 1303 (Fed. Cir. 2005).
See, e.g., In re Rambus, Inc., 694 F.3d 42, 46 (Fed. Cir.
2012); see also M.P.E.P. § 2258(G) (“In a reexamination
proceeding involving claims of an expired patent, claim
construction pursuant to the principle[s] set forth by the
court in Phillips, . . . should be applied since the expired
claim[s] are not subject to amendment.”); 1 Patent Office
Litigation § 4:70 (justifying the shift from the broadest
reasonable interpretation to the standard used by district
courts because “claims may not be amended in an expired
patent and the sole basis for the ‘broadest reasonable
interpretation’ rubric is the ability to amend claims”). In
this appeal, we apply the Phillips claim construction
standards.
A patent is anticipated “if a single prior art reference
discloses each and every limitation of the claimed inven-
tion.” Schering Corp. v. Geneva Pharm., 339 F.3d 1373,
1377 (Fed. Cir. 2003) (citing Lewmar Marine, Inc. v.
Barient, Inc., 827 F.2d 744, 747 (Fed. Cir.1987). Anticipa-
tion is a question of fact reviewed for substantial evi-
dence. See In re Baxter Travenol Labs., 952 F.2d 388, 390
(Fed. Cir. 1991). Substantial evidence is more than a
6 IN RE RAMBUS, INC.
“mere scintilla of evidence” but something less than the
“weight of the evidence.” In re Kotzab, 217 F.3d 1365,
1369 (Fed. Cir. 2000) (citing in re Gartside, 203 F.3d 1305,
1316 (Fed. Cir. 2000)).
ANTICIPATION
The Board relied on Figs. 25a and 25b in Bennett, and
the related “Parameter VI.” These figures are schematic
representations of operations occurring on a memory bus.
Parameter VI is the internal parameter in Bennett that
determines whether the data and wait lines in these
figures are dedicated or multiplexed. Specifically, when
Parameter VI is 1 (as in Fig. 25a), these lines are multi-
plexed, and when it is 3 (as in Fig. 25b), each signal has a
dedicated line. As explained in more detail below, the
data transfer in Fig. 25a takes place one clock cycle later
than the data transfer in Fig. 25b.
IN RE RAMBUS, INC. 7
The labels at the top of Figs. 25a and b (T0, T1, T2,
etc.) refer to clock cycles. Bennett has assumed for sim-
plicity that each operation in the figures (begin signal,
arbitration, wait signal, data transfer, etc.) takes exactly
one clock cycle.
In Fig. 25b, the wait and data signals each have dedi-
cated lines. As such, these signals can both be sent on the
bus at the same time. Specifically, the first wait and data
signals are both sent between the T2 and T3 clock cycles.
In Fig. 25a, by contrast, the wait and data signals are
multiplexed, so they cannot use the bus at the same time.
As a result, the first wait signal is sent between T2 and
T3 but the first data signal is sent one clock cycle later,
between T3 and T4.
Micron’s argument below, with which the Board
agreed, is as follows. The multiplexed lines in Fig. 25a
cause a delay of known value (one clock cycle) before data
transfer. Setting Parameter VI to 1 causes the lines to be
multiplexed. Therefore, Parameter VI is a “value that is
representative of an amount of time to transpire after
which the memory device outputs the first amount of
data.”
Rambus responds that these figures are simplified,
hypothetical, illustrations of how the invention in Bennett
works in theory and not schematics of how Bennett works.
For instance, Rambus points out that, in practice, arbitra-
tion takes an unknown amount of time because a device
may lose arbitration a number of times in a row. Rambus
argues that the wait signal may also delay the data
transfer for an indeterminate amount of time if it indi-
cates that the memory device is busy. Thus, according to
Rambus, when the invention disclosed in Bennett actually
functions, it does not include a known delay time; rather,
it has an indefinite delay time based upon arbitration,
busy memory devices, and other functions.
8 IN RE RAMBUS, INC.
We agree with Rambus. In Figs. 25a and b of Ben-
nett, Parameter VI is only “representative” of one source
of delay because the actual delay can be longer due to
other factors. Switching this parameter from 1 to 3 does
not necessarily create a one clock cycle delay before data
is transferred due to further potential delay that may
result from arbitration. As such, Parameter VI is not a
“value that is representative of an amount of time to
transpire after which the memory device outputs the first
amount of data.”
As Rambus points out, arbitration may take an inde-
terminate amount of time because a memory device may
“lose” arbitration on successive occasions. If arbitration
in Fig. 25b happens to take longer than in Fig 25a, the
memory system with multiplexed lines (Fig. 25a) may
actually have less delay before data transfer. Similarly, a
busy memory device with dedicated lines may have a
longer delay, due to wait signals, than an available device
with multiplexed lines. Because of these two additional,
indefinite, sources of delay, changing Parameter VI from 1
to 3 will not produce a set amount of time after which
data is transferred. Therefore, Parameter VI is not
“representative” of an amount of time after which data is
transferred.
The Board found that, in at least some embodiments
in Bennett, Parameter VI meets the claim limitation at
issue. Specifically, when the embodiments in Fig. 25a
and b both (1) win arbitration on the first attempt and (2)
are not busy for an indeterminate amount of time, then
Parameter VI is a “value that is representative of an
amount of time to transpire after which the memory
device outputs the first amount of data.” We disagree. A
value cannot “represent” an “amount of time” if there are
additional factors, wholly unrepresented by that value,
that necessarily impact, or represent, the “amount of
time.” Certainly, Parameter VI is one factor that may
affect the amount of time that passes before data is trans-
IN RE RAMBUS, INC. 9
ferred but it does not represent that time. Accordingly,
we reverse the Board’s decision that Bennett anticipates
claims 26 and 28 of the ’916 patent.
REVERSED