Ex Parte Lai et al

Board of Patent Appeals and Interferences

Jul 22, 2008

10144126 (B.P.A.I. Jul. 22, 2008)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
____________

Ex parte CHENG-TIEN LAI, TSUNG-LUNG LEE and SHENGHUA
WANG
____________

Appeal 2008-2340
Application 10/144,126
Technology Center 3700
____________

Decided: July 22, 2008
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Before CHUNG K. PAK, ROMULO H. DELMENDO, and LINDA M.
GAUDETTE, Administrative Patent Judges.

GAUDETTE, Administrative Patent Judge.

DECISION ON APPEAL
This is an appeal from the final rejection of claims 1-6, 10-14, and
18. Claims 7-9 and 15-17 are pending, but have been withdrawn from
consideration. We have jurisdiction under 35 U.S.C. § 6(b).
We REVERSE.
Appeal 2008-2340
Application 10/144,126

The invention relates to a heat pipe for a heat sink assembly. (Spec.
[0001]). The general structure and operation of a heat pipe is described in
the Specification (¶ [0003]) as follows:
Conventional heat pipes are sealed vacuum vessels that
are partly filled with working fluid. When external heat is input
at an evaporating end, the working fluid is vaporized, creating a
pressure gradient in the heat pipe. This pressure gradient forces
the vapor to flow along the heat pipe to a cooler section (a
condensing end) where it condenses and releases latent heat that
was absorbed in the process of the vaporization. The condensed
working fluid then returns to the evaporating end through a
wicking structure that provides capillary forces. There are
several types of wicking structures in common use, including
grooves, screening, fibers, and sintered metal powder.

Claims 1 and 10 are illustrative of the heat pipe of the present
invention and a method of use therefor:
1. A heat pipe comprising:
an inner pipe receiving working fluid;
an inner pipe fixedly received in the outer pipe, at least one cutout
being defined in each of opposite ends of the inner pipe for allowing the
working fluid to pass between the inner pipe and the outer pipe; and
a gap defined between the outer pipe and the inner pipe, wherein the
gap is very narrow such that an inner wall of the outer pipe and an outer wall
of the inner pipe cooperatively form a wicking structure;
wherein the inner pipe has a height approximately equal to a height of
the outer pipe and wherein the working fluid passes between the inner pipe
and the outer pipe only through the at least one cutout defined in each of
opposite ends of the inner pipe.

10. A heat pipe for dissipating heat from a heat-generating
electronic device, the heat pipe comprising:
an outer pipe comprising an evaporating end and a condensing end,
one of the evaporating end and the condensing end being integrally sealed;
an inner pipe received in the outer pipe and having a height
approximately equal to a height of the outer pipe, the inner pipe and the
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Application 10/144,126

outer pipe being in communication with each other respectively at the
evaporating and condensing ends only, wherein the inner pipe and the outer
pipe cooperatively form a wicking structure therebetween; and
working fluid received in the evaporating end of the outer pipe and a
corresponding end of the inner pipe,
wherein when the evaporating end of the outer pipe is heated, the
working fluid evaporates, flows inside the inner pipe to the condensing end,
condenses at the condensing end, and flows back to the evaporating end
through the wicking structure.

The Examiner relies on the following prior art references to show
unpatentability:
Levedahl 3,528,494 Sep. 15, 1970
Low 3,789,920 Feb. 5, 1974
Rosenfeld 5,076,352 Dec. 31, 1991

The Examiner made the following rejections:
1. Claim 1 under 35 U.S.C. § 102(b) as anticipated by Levedahl.
2. Claims 2-5, 10-13, and 18 under 35 U.S.C. § 103 as unpatentable
over Levedahl in view of Low.
3. Claims 6 and 14 under 35 U.S.C. § 103 as unpatentable over
Levedahl in view of Rosenfeld.
The Examiner relies on Levedahl for a disclosure of the invention as
claimed in independent claims 1, 10, and 18. (Ans. 3-5.) The Examiner
relies on the secondary references solely for a disclosure of features recited
in the dependent claims. (Ans. 4 (Low) and 5 (Rosenfeld).) Appellants
argue, inter alia, that Levedahl fails to disclose or suggest a heat pipe in
which an inner pipe has a height approximately equal to the height of the
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Application 10/144,126

outer pipe as required by each of the independent claims 1, 10, and 14.
(App. Br. 11.)
The issue thus presented is: Have Appellants shown that the
Examiner reversibly erred in rejecting the claims based on an unsupported
finding that Levedahl discloses or suggests a heat pipe in which an inner
pipe has a height approximately equal to the height of the outer pipe? We
answer this question in the affirmative.
The following findings of fact are relevant to our determination of this
issue:
1) Levedahl discloses a heat pipe comprising “an
evaporator section 12, a transport section 14 and a condenser
section 16. The ends of the pipe are closed and are provided
with capillary fluid transport means on the inner surface
thereof.” (Col. 3, ll. 54-57.)
2) Levedahl states that “for each section of the heat pipe,
‘ideal’ capillary configurations are provided to achieve for the
specific function of the respective sections, optimum
condensation, evaporation and capillary transport as required.
(Col. 3, ll. 67-70.)
3) Levedahl discloses that “[u]nder some conditions the
best cross-sectional configuration of the transport section may
be that of two concentric tubular members such as cylinders.”
(Col. 5, ll. 17-19.) Levedahl states that in this configuration,
illustrated in Figure 8, the outer casing 110 acts in a similar
manner to the casing 10 shown in figure 1 (col. 5, ll. 21-23) and
“the inner concentric tubular member 118 acts in conjunction
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Appeal 2008-2340
Application 10/144,126

with the outer casing 110 to form therebetween spaced,
generally parallel surfaces 114 and 112 respectively, forming a
capillary flow path 124 for condensed liquid” (col. 5, ll. 23-27).
The Examiner maintains that “[t]he outer pipe 120 and the inner pipe
110 of the Levedahl’s [sic] reference are approximately equal in height (see
figure 1 and 8).” (Ans. 6.) Appellants argue that Levedahl only discloses
the use of an inner pipe in the transport section 14 and, therefore, the height
of the inner pipe is not approximately equal to that of the outer pipe, which
is the height of the combined evaporator 12, transport 14, and condenser 16
sections. (App. Br. 16.)
During examination, claim terms must be given their broadest
reasonable construction consistent with the specification. In re Icon Health
and Fitness, Inc., 496 F.3d 1374, 1379 (Fed. Cir. 2007). A claim term such
as “approximately” is generally interpreted as meaning something less than
perfect, or allowing for some amount of deviation from an exact boundary.
See Playtex Products, Inc. v. Procter & Gamble Co., 400 F.3d 901, 907
(Fed. Cir 2005) and cases cited therein.
Appellants’ Specification does not include a definition of the term
“approximately equal” nor does the Specification provide any numerical
values for the respective heights of the inner and outer pipes. The
Specification does state that “[t]he inner pipe 20 has a height approximately
equal to a height of the outer pipe 10, and has an outer diameter slightly less
than an inner diameter of the outer pipe 10” (Spec. [0014]). The
Specification further describes the gap between the inner and outer pipes as
“very narrow” such that “surface tension of the working fluid and capillary
action of the outer and inner pipes 10, 20 is enhanced.” (Spec. [0015].)
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Application 10/144,126

Therefore, we interpret the claims as requiring inner and outer pipes in
which any difference in height is something less than the distance of the very
narrow gap, i.e., essentially imperceptible.
Based on this claim interpretation, we are in agreement with
Appellants that Levendahl does not disclose a structure in which the inner
and outer pipes are “approximately equal” in height as claimed (FF 3). We
are further in agreement with Appellants’ contention that Levedahl clearly
discloses three separate sections having distinct configurations (FF 1 and 2).
(App. Br. 15.)
Appellants also argue that the applied prior art fails to disclose or
suggest modification of Levedahl’s structure to achieve the claimed inner
and outer pipes of approximately equal height; i.e., there is no indication in
Levedahl that the evaporator 12 and condenser 16 sections could be
configured using the concentric tubular structure of the transport section 14.
(App. Br. 16.) The Examiner has not addressed this argument. (See Ans. 6.)
The Examiner has not identified a teaching or suggestion in the prior art, nor
explained why one of ordinary skill in the art would have been motivated to
modify Levedahl’s structure such that the inner pipe has a height
approximately equal to the height of the outer pipe. (See Ans. 3-6.)
In view of the foregoing, we find that the Examiner failed to establish
a prima facie case of anticipation (claim 1) and obviousness (claims 2-6, 10-
14, and 18).

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Appeal 2008-2340
Application 10/144,126

REVERSED

tc

WEI TE CHUNG
FOXCONN INTERNATIONAL, INC.
1650 MEMOREX DRIVE
SANTA CLARA, CA 95050

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