Chamberlain Group, Inc. v. Lear Corp.

United States Court of Appeals for the Federal Circuit
2007-1314, -1467

THE CHAMBERLAIN GROUP, INC.,

Plaintiff-Appellee,

and

JOHNSON CONTROLS INTERIORS LLC,

Plaintiff-Appellee,

v.

LEAR CORPORATION,

Defendant-Appellant.

Donald R. Dunner, Finnegan, Henderson, Farabow, Garrett & Dunner, L.L.P, of
Washington, DC, argued for plaintiffs-appellees. With him on the brief for Johnson
Controls Interiors LLC, were Don O. Burley and Kara F. Stoll. Of counsel on the brief
were Philip J. Kessler, J. Michael Huget, and Deborah Swedlow, Butzel Long, of Ann
Arbor, Michigan. On the brief for the Chamberlain group, Inc. were Karl R. Fink, Rudy I.
Kratz, and Nicholas T. Peters, Fitch, Even, Tabin & Flannery, of Chicago, Illinois.

Kimball R. Anderson, Winston & Strawn LLP, of Chicago, Illinois, argued for
defendant-appellant. With him on the brief were Gene C. Schaerr and Scott H. Blackman,
of Washington, DC. Of counsel on the brief were Ernie L. Brooks, Frank A. Angileri, and
Mark D. Chuey, Brooks Kushman P.C., of Southfield, Michigan.

Appealed from: United States District Court for the Northern District of Illinois

Senior Judge James B. Moran
 United States Court of Appeals for the Federal Circuit
2007-1314, -1467

THE CHAMBERLAIN GROUP, INC.,

Plaintiff-Appellee,
and

JOHNSON CONTROLS INTERIORS LLC,

Plaintiff-Appellee,

v.

LEAR CORPORATION,

Defendant-Appellant.

Appeal from United States District Court for the Northern District of Illinois in case no.
05-CV-3449, Senior Judge James B. Moran.

___________________________

DECIDED: February 19, 2008
___________________________

Before RADER, Circuit Judge, CLEVENGER, Senior Judge, and DYK, Circuit Judge.

RADER, Circuit Judge.

The Chamberlain Group, Inc. (Chamberlain) owns U.S. Patent No. 6,154,544

(’544 patent), an invention that improves security in garage door openers. Chamberlain

and Johnson Controls Interiors LLC (JCI), Chamberlain’s exclusive licensee with

respect to development of radio frequency transmitters for sale to automotive original

equipment manufacturers, sued Lear Corp. (Lear), charging Lear’s Car2U transmitter

with infringement of claim 4 of the ’544 patent. After a Markman hearing, a claim

construction order, Chamberlain Group, Inc. v. Lear Corp., No. 1:05-CV-03449 (N.D. Ill.
Sept. 11, 2006) (Initial Markman Order), and a modified claim construction order,

Chamberlain Group, Inc. v. Lear Corp., No. 1:05-CV-03449 (N.D. Ill. Feb. 20, 2007)

(Modified Markman Order), the United States District Court for the Northern District of

Illinois issued a preliminary injunction, Chamberlain Group, Inc. v. Lear Corp., No. 1:05-

CV-03449 (N.D. Ill. Mar. 30, 2007) (Preliminary Injunction Order). The trial court,

however, stayed that injunction for Lear’s contracts with General Motors Corp.

Chamberlain Group, Inc. v. Lear Corp., No. 1:05-CV-03449 (N.D. Ill. Apr. 25, 2007)

(Partial Stay Order). Because the district court erred in construing the claim term

“binary code,” this court reverses the district court’s claim construction, vacates the

preliminary injunction, and remands.

I

The remote-control garage door opening systems claimed in the ’544 patent

comprise a transmitter (generally integrated into a vehicle’s visor or rearview mirror) and

a receiver (usually attached to a mechanical device that operates the garage door).

The transmitter and receiver communicate via an encrypted signal on a radio frequency

(RF) carrier. In the claimed invention, part of the signal changes with each transmission

(rolling or variable code). The rest of the signal remains fixed (fixed code). The

receiver compares the transmitted fixed code and the rolling code with stored codes to

activate the door opener.

The ’544 patent improved the prior art of remote-control garage doors with an

enhanced encryption system to make cracking the code more difficult for would-be

techno-burglars. Specifically, asserted claim 4, and claims 1 and 3 from which it

2007-1314, -1467 2
depends, recites the generation and transmission of a “trinary code” to encrypt the

transmitted signal:

Claim 1:

A transmitter for sending an encrypted signal to control an actuator, comprising:

oscillator for generating a radio frequency oscillatory signal;

apparatus for enabling the sending of an encrypted signal;

binary code generator responsive to the enabling apparatus for generating a
variable binary code, said variable code being different for each enabling by the
enabling device;

trinary code generator for generating a three-valued or trinary code responsive to
the variable binary code; and

transmitting apparatus for modulating the radio frequency oscillatory signal with
the trinary code to produce a modulated trinary coded variable radio frequency
signal for operation or control of a secure actuator.

Claim 3:

A transmitter for sending an encrypted signal to control an actuator according to claim 1,
comprising apparatus for producing a fixed code signal and for combining said
fixed code signal with a rolling code signal.

Claim 4:

A transmitter for sending an encrypted signal to control an actuator according to claim 3,
comprising apparatus for interleaving trinary bits derived from said fixed code
signal with trinary bits derived from said rolling code signal to produce a trinary
interleaved fixed and rolling code signal.

’544 patent col.9 l.56–col.10 l.4, col.10 ll.10-18. Claim 4 itself includes the additional

feature of producing a trinary code signal comprising trinary bits derived from both a

fixed code and a rolling code, interleaved together.

The key claim construction issue on appeal is the interpretation of the word

“code” as it is used in the ’544 patent. The district court construed four terms that

2007-1314, -1467 3
require an understanding of “code”: “binary code” (claim 1), “binary code generator”

(claim 1), “trinary code generator for generating a three-valued or trinary code

responsive to the variable binary code” (claim 1), and “apparatus for producing a fixed

code signal and for combining said fixed code signal with a rolling code signal” (claim

3). Initial Markman Order at 5-11. Although the district court did not construe it, the

meaning of “trinary code” is also relevant to construing “code” and ultimately to

understanding “binary code,” since “binary” and “trinary” are themselves closely related

terms and presumptively modify “code” in parallel ways.

The district court defined “binary code” as “a code in which each code element

may be either of two distinct kinds of values, which code may represent various kinds of

letters and numbers including, but not limited to, a representation of a base 2 number.”

Id. at 8. On Lear’s motion for reconsideration, the district court clarified that “‘binary

code’ cannot encompass trinary code.” Modified Markman Order at 4. As for “trinary

code,” this term is defined to some extent by the specification as a “three-valued” code.

See ’544 patent, col.9 ll.66-67 (claim 1); see also id. col.3 ll.23-25.

On Chamberlain’s motion for a preliminary injunction, the district court applied its

definitions of “binary code” and the other disputed terms to Lear’s Car2U transmitter.

Lear characterized its transmitter as using only trinary numbers and trinary algorithms,

therefore operating in trinary code rather than binary code. The district court noted that

while Lear’s Car2U code might represent a trinary number, Lear conceded that this

trinary number is still represented as 0s and 1s in a computer. Preliminary Injunction

Order at 6. Indeed, the parties agree that all computers necessarily operate in “binary

code.” In other words, microprocessors and memory devices use low and high voltages

2007-1314, -1467 4
to manipulate, transmit, receive, and store vast amounts of data. A low voltage

represents a 0, while a high voltage represents a 1. Thus the district court

characterized Lear’s trinary number, as represented in a computer, as a “binary-coded

trinary number.” Id. at 7. On this basis, the court concluded that Lear’s accused Car2U

transmitter would likely satisfy the “binary code” limitation. Id. at 6-7. Also, according to

the district court, Lear admitted that its product generated trinary code, so the district

court likewise concluded that Lear’s binary and trinary codes had to be generated by

binary code generators and trinary code generators, making it likely that Lear’s product

met the “binary code generator” and “trinary code generator” limitations. Id. at 7.

Further finding that Lear likely met the “fixed code” limitation of claim 3, the district court

concluded that Chamberlain would likely prevail on the merits of its infringement claim.

Id. at 8-9. From there, the district court evaluated the remaining parts of the traditional

four-factor test for injunctive relief, see eBay, Inc. v. MercExchange L.L.C., 126 S. Ct.

1837, 1839 (2006), and imposed a preliminary injunction on Lear, Preliminary Injunction

Order at 9-14 (as modified by Partial Stay Order).

II

This court reviews claim construction as an issue of law without deference.

Cybor Corp. v. FAS Techs., Inc., 138 F.3d 1448, 1451 (Fed. Cir. 1998) (en banc). To

construe a claim term, the trial court must determine the meaning of any disputed words

from the perspective of one of ordinary skill in the pertinent art at the time of filing.

Intrinsic evidence, that is the claims, written description, and the prosecution history of

the patent, is a more reliable guide to the meaning of a claim term than are extrinsic

sources like technical dictionaries, treatises, and expert testimony. Phillips v. AWH

2007-1314, -1467 5
Corp., 415 F.3d 1303, 1318-19 (Fed. Cir. 2005) (en banc). Although it is unacceptable

to import limitations into a claim from the written description, “the specification ‘is always

highly relevant to the claim construction analysis. Usually, it is dispositive; it is the

single best guide to the meaning of a disputed term.’” Id. at 1315 (quoting Vitronics

Corp. v. Conceptronic, Inc., 90 F.3d 1576, 1582 (Fed. Cir. 1996)).

A

The district court defined “binary code” in the ’544 patent as “a code in which

each code element may be either of two distinct kinds of values, which code may

represent various kinds of letters and numbers including, but not limited to, a

representation of a base 2 number.” Initial Markman Order at 8. The trial court also

explained that “binary code” can encompass not only binary numbers, but also other

numbers or symbolic designations that are represented in a system using two types of

values (e.g., 0s and 1s). See id. at 6-8. In other words, “binary code” refers to the basic

form for computer expression or storage of a given number or term, rather than its

meaning. Under the district court’s interpretation, “binary code” could serve as a

medium to express binary (base 2) numbers (0, 1, 10, 11, 100, etc.), trinary (base 3)

numbers (0, 1, 2, 10, 11, etc.), decimal (base 10) numbers (0, 1, 2, 3, 4, etc.), or any

other base for that matter, by aggregating individual bits into combinations representing

higher-based numbers.

Thus for the district court, Lear’s “binary-coded trinary numbers” were binary

code, not trinary code. The significance of this distinction depends on an examination

of the operation of binary and trinary number systems in a computer. For example, the

trinary numbers 0, 1, and 2 can be represented in binary code using pairs of bits 00, 01,

2007-1314, -1467 6
and 10, respectively. Rather than reading each individual bit as representative of a

power of 2, as with binary numbers, the computer must recognize each pair of bits as

representing a power of 3. In a computer, as a further example, the decimal number 4,

equivalent to the binary number 100 and the trinary number 11, would appear in the

computer’s “binary code” as either the binary number 100 or the binary-coded trinary

number 0101. 1 To convert the “binary-coded trinary number” 0101 back to a decimal

number, the former bit pair “01” represents 1 x 31 = 3, and the latter bit pair “01”

represents 1 x 30 = 1, and 3 + 1 = 4. Of course, the person or device reading the string

of 0s and 1s must know the base of numbers that the computer encodes. Otherwise

the person or device cannot know, for example, whether 1000 means 8 (if 1000 is a

binary number), 6 (if 1000 is a “binary-coded trinary number”), 27 (if 1000 is a trinary

number), or something else entirely.

1
In general, whole, non-negative numbers of base x (e.g. x = 2 for binary
numbers; x = 3 for trinary numbers) can be expressed in the more familiar base 10 (i.e.
decimal) system as:
n

Σi=0
aixi

where a is the base 10 system value of the digit or combination of digits being summed,
n is the number of digits in the number being converted and where i is the position of
the digit in the number, starting with 0 and counting from the right. (To express
fractional or negative numbers, the formula is slightly more complicated. Expression of
integers ≥ 0, however, is sufficient for purposes of this discussion.) To illustrate using
the example above, the binary number 100 can be expressed as 1 x 22 + 0 x 21 + 0 x 20
= 4. Likewise, the trinary number 11 can be expressed as 1 x 31 + 1 x 30 = 4. The
binary-coded trinary number 0101 must first be broken apart into bit pairs, 01 and 01 in
this case, with each bit pair representing a trinary number (here, 01 = 1). The trinary
values of the bit pairs are then plugged into the above formula to convert the binary-
coded trinary number 0101 into the decimal number 4. For further judicial explanation
of the binary system compared with the decimal system of positional notation, see
Gottschalk v. Benson, 409 U.S. 63, 66-67 (1972).

2007-1314, -1467 7
 In this case, Lear argues that the ’544 patent uses the term “binary code” in a

more constrained manner than its broad general application to computer language.

According to Lear, the patent uses the term to represent meaning of the message, not

its mere form. In other words, the computer symbols and language that the district court

called a “binary-coded trinary number,” Preliminary Injunction Order, slip op. at 7, under

Lear’s interpretation, is not a binary code at all. Instead, it is a trinary code, because the

bit pairs symbolize any of three values, rather than two.

In construing “binary code,” the district court first noted that the claims use the

language “binary code” and “binary signal” rather than “binary number” or “base 2

number.” Initial Markman Order at 6. While recognizing that the preferred embodiment

describes translating “trinary bits” back into “a binary number” in the receiver, ’544

patent col.8 ll.45-48, the district court perceived that limiting “binary code” to binary

numbers on this basis alone would improperly import a limitation into the claims from

the specification, Initial Markman Order at 7. The district court then turned to extrinsic

sources, namely the IEEE Standard Dictionary of Electrical and Electronic Terms, Sixth

Edition, to seek the meaning one of ordinary skill in the art would customarily ascribe to

“binary code.” Id. at 7-8. This reasoning led the trial court to its interpretation of the

disputed claim terms.

B

The district court commendably strove to follow this court’s rules for claim

construction. See Phillips, 415 F.3d at 1318-19. In this regard, the trial court weighed

the intrinsic evidence along with the extrinsic evidence and properly sought to avoid

importing a limitation from the specification into the claims. See id. Nonetheless, this

2007-1314, -1467 8
court discerns that the ’544 patent specification gives particular limiting meanings to the

language in the claims. Specifically, the ’544 patent used “binary code” to mean “binary

number.” While the district court’s construction may represent an ordinary or customary

reading of “binary code,” the ’544 patent restricts “binary code” to a narrower meaning.

See id. at 1316 (“The construction that stays true to the claim language and most

naturally aligns with the patent’s description of the invention will be, in the end, the

correct construction.”) (quoting Renishaw PLC v. Marposs Societa’ per Azioni, 148 F.3d

1243, 1250 (Fed. Cir. 1998)).

At the outset, this court examines the meaning of “code” as used in the claims.

In this context, the ’544 patent’s term “trinary code” is relevant to construing “binary

code” because the term “code” presumptively should carry the same meaning

throughout the patent. See id. at 1314 (“claim terms are normally used consistently

throughout the patent.”). The crux of the dispute over “binary code” centers on the

“code” part of that term. The parties agree that “binary” means “base 2,” and “trinary”

means “base 3,” or as claim 1 itself states, “three-valued.” ’544 patent col.9 ll.66-67.

Thus, “binary code” and “trinary code” should have parallel meanings, differing only

insofar as “binary” and “trinary” differ in their relationships to the numbers 2 and 3.

Because the trinary code of the ’544 patent is stored in the transmitter’s

microcontroller, and the transmitter’s microcontroller, like other computers, undisputedly

stores and processes data as sequences of 0s and 1s, “trinary code” as used in the

’544 patent means values stored and processed in the binary language as 0s and 1s.

According to claim 1, the trinary code is generated by the trinary code generator, and is

responsive to a variable binary code. Id. col.9 ll.62-67. Contrary to Chamberlain’s

2007-1314, -1467 9
assertions, 2 the ’544 patent notes that the transmitter’s microcontroller generates the

trinary code. Thus, the last limitation of claim 1, “transmitting apparatus for modulating

the radio frequency oscillatory signal with the trinary code to produce a modulated

trinary coded variable radio frequency signal for operation or control of a secure

actuator,” id. col.10 ll.1-4, cuts against Chamberlain’s position. This claim presupposes

that the trinary code already exists (in the transmitter’s microcontroller) because it

expects the transmitter to use that trinary code to modulate the RF signal. The rest of

the ’544 specification points to the same conclusion. See id. col.5 ll.17-24 (“The

microcontroller 78 is connected by a serial bus 79 to a non-volatile memory 80. An

output bus 81 connects the microcontroller to a radio frequency oscillator 82. The

microcontroller 78 produces coded signals when the button 72 is pushed causing the

output of the RF oscillator 82 to be amplitude modulated to supply a radio frequency

signal at an antenna 83 connected thereto.” (referring to Figure 2, a block diagram of

the transmitter) (emphasis added)); see also id. col.3 ll.23-25 (“The transmitter then

converts the 32-bit fixed code and the mirrored variable code to a three-valued or trinary

2
Chamberlain apparently realized that the only way that the district court’s
construction of “binary code” did not contradict the patent’s use of “trinary code,” as
explained below, is if there is no trinary code inside the transmitter’s microcontroller.
Chamberlain argued that trinary code forms exclusively outside the transmitter’s
“computer,” at the very end of the signal generation and transmission process.
According to Chamberlain, binary code inside the computer, or more accurately, inside
the transmitter’s microcontroller, generates trinary code through the introduction of
timing pulses to modulate a RF oscillating signal. To the contrary, the figures and prose
in the specification do not support Chamberlain’s “no trinary code in the computer”
theory. As explained herein, the specification shows that the “trinary code” in the ’544
patent is in fact generated and manipulated inside the transmitter’s microcontroller.
While the ’544 patent supplies a convincing construction of “binary code” and “trinary
code,” Chamberlain did not identify even any expert reports or testimony in support of
its particular claim meaning theory.

2007-1314, -1467 10
bit fixed code and a three-valued or trinary bit variable code or rolling code.”) (Summary

of the Invention) (emphases added)).

This court also discerns further evidence that the patent places both the

generation and manipulation of the trinary code within the transmitter’s microcontroller.

Specifically, the patent describes the process of generating the trinary-coded RF signal.

Both the preferred embodiment and claim 4 put both the fixed trinary code and the

rolling trinary code in that generating process:

The rolling code is then changed to a trinary code having values 0, 1 and
2 and the initial trinary rolling code is set to 0. It may be appreciated that it
is trinary code which is actually used to modify the radio frequency
oscillator signal and the trinary code is best seen in FIG. 6. It may be
noted that the bit timing in FIG. 6 for a 0 is 1.5 milliseconds down time and
0.5 millisecond up time, for a 1, 1 millisecond down and 1 millisecond up
and for a 2, 0.5 millisecond down and 1.5 milliseconds up. The up time is
actually the active time when carrier is being generated. The down time is
inactive when the carrier is cut off. The codes are assembled in two
frames, each of 20 trinary bits, with the first frame being identified by a 0.5
millisecond sync bit and the second frame being identified by a 1.5
millisecond sync bit.

Id. col.7 ll.13-30 (emphasis added).

The district court explained that its construction of “binary code” encompassed

anything represented in 0s and 1s in a computer. See, e.g., Preliminary Injunction Order

at 6-7. Accordingly, the trial court’s construction of “binary code” would also encompass

values expressed in “trinary code,” as the latter term is used throughout the ’544 patent.

But, as the district court itself recognized, “binary code” cannot include “trinary code.”

The patent claims and specification, moreover, do not permit these two terms to

overlap. See, e.g., ’544 patent col.9 l.67 (the trinary code is “responsive to” the binary

code) (claim 1); col.7 ll.12-14 (the rolling binary code “is changed to” trinary code by the

transmitter); col.3 ll.24-26 (the transmitter “converts” the 32-bit codes (which are binary)

2007-1314, -1467 11
to trinary codes). Thus, the district court’s construction of “binary code” is internally

inconsistent and contradictory to the rest of the patent. To resolve this contradiction

and preserve the independent meaning of “binary code” as compared to “trinary code”

in the ’544 patent, this court reads “binary code” as limited to binary numbers, and

“trinary code” as limited to trinary numbers. Because the substance, rather than the

form, controls whether a “code” is “binary” or “trinary” for the ’544 patent, trinary code is

still trinary code when expressed as a trinary number represented by (base 2) bit pairs,

using 0s and 1s, as in the transmitter’s microcontroller, or when expressed as a trinary

number represented in (base 3) timed pulses as in the modulated RF signal transmitted

to the receiver. The “binary-coded trinary number[s]” described by the district court,

Preliminary Injunction Order at 7, are therefore trinary codes, not binary codes.

C

Because “binary code” or “trinary code” appears in the other three claim terms

construed by the district court, the district court’s erroneous interpretation of “binary

code” also necessarily renders incorrect its construction of these other terms. On this

appeal, Lear does not identify any other errors in the district court’s claim construction.

III

This court reviews a grant or denial of a preliminary injunction for abuse of

discretion. Amazon.com, Inc. v. Barnesandnoble.com, Inc., 239 F.3d 1343, 1350 (Fed.

Cir. 2001). Where a district court relies on an erroneous claim construction in granting

injunctive relief, this legal error may well constitute an abuse of discretion requiring this

court to vacate the injunction. See SRAM Corp. v. AD-II Eng’g, Inc., 465 F.3d 1351,

1352-53 (Fed. Cir. 2006) (“Because the district court erred in construing claim 16, we

2007-1314, -1467 12
vacate the district court’s . . . grant of an injunction against AD-II, and remand for further

proceedings consistent with this opinion.”). A preliminary injunction requires analysis of

the likelihood of success on the merits. See Abbott Labs. v. Andrx Pharms., Inc., 452

F.3d 1331, 1334 (Fed. Cir. 2006) (quoting Polymer Techs., Inc. v. Bridwell, 103 F.3d

970, 973 (Fed. Cir. 1996)). This factor, in turn, depends fundamentally on the meaning

of the asserted claim and its relationship to the accused product or process. Therefore,

a correct claim construction is almost always a prerequisite for imposition of a

preliminary injunction.

In this case, this court discerns that the errors in claim construction will

fundamentally influence the likelihood of success in proving infringement. Thus, the

district court’s erroneous construction of the disputed terms requires this court to vacate

the preliminary injunction. On remand, the district court will also have the opportunity to

reassess admissions by either party that were contingent on rejected claim meanings. 3

REVERSED, VACATED, AND REMANDED

COSTS

Each party shall bear its own costs.

3
For example, Lear’s contention that its product generated trinary codes
(but not binary codes) does not necessarily admit that Lear’s product met the “trinary
code generator” limitation. See Preliminary Injunction Order at 7. Instead Lear’s
contention may only illustrate its reliance on a different interpretation of “binary code”
and “trinary code generator.”

2007-1314, -1467 13