DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA . If status of the application as subject to 35 U.S.C. 102 and 103 is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
Status of Claims
Claims 16-18 & 20-30 are pending in the application and are presently examined. Claims 16-30 were rejected in the 4/10/2026 office action. Applicant cancelled claim 19.
Information Disclosure Statement
The 6/12/2026 information disclosure statement has been considered by the examiner. The reference, with a line through it, has not been considered by the examiner because a translation was not provided.
Response to Amendment / Arguments
The 7/7/2026 amendment, in response to the 4/10/2026 office action, has been entered. Applicant’s claim amendments overcame the objections and the 35 U.S.C. 112(b) rejection.
Applicant's arguments, regarding the 35 U.S.C. 103 rejections, have been fully considered, but they are not persuasive. Claim 16 was rejected under 35 U.S.C. 103 as being unpatentable over US20150340713A1 (Tanno) in view of “Hydrophilic carbon onions synthesized by millisecond pulsed laser irradiation” (Hu), US20130171547A1 (Tanno2). The issue is whether or not the prior art teaches the following claim 16 limitation:
“the surface to be rendered hydrophilic is irradiated with a pulsed laser having a power density of at least 0.5 MW/mm2”
Applicant argues that the following teaching of Tanno teaches away from the “0.5 MW/mm2” claim limitation:
“[0045] …If the laser spot diameter is less than 50 μm, the power density becomes excessive and the separator heats up during processing, giving rise to warping, as a result of which the contact resistance may increase. On the other hand, if this exceeds 800 μm, the power density becomes low and the removal of resin ingredients from the separator surface layer is inadequate, which may lead to declines in the hydrophilicity and electrical conductivity.”
Examiner disagrees that Tanno teaches away from ≥ 0.5 MW/mm2. “0.5 MW/mm2” is a combination of laser power (MW) and spot area (mm2). Tanno only mentions spot diameter, from which spot area can be calculated. Tanno doesn’t address any numerical value of laser power or power density. In paragraph 45, Tanno doesn’t teach the claimed range of ≥ 0.5 MW/mm2 directly, or with laser power and spot area combined, and Tanno doesn’t teach away from it either.
Tanno does give guidance for laser power density optimization: high enough for hydrophilicity but not so high that the separator warps. Thus, Tanno teaches away from use of laser power density that would warp the separator, but not away from a specific laser power density range.
Tanno provides sufficient guidance to one of skill in the art to optimize laser power density and achieve the claimed limitation without undue experimentation (make it hydrophilic but don’t damage it).
Applicant next argues:
“Hu discloses a method of producing carbon onions, and Tanno discloses a method of laser irradiating a surface of an article molded from a composition comprising a graphite powder, an epoxy resin, a phenolic resin, a curing accelerator, and an internal mold release agent. Therefore, the Applicant respectfully submits that one of ordinary skill in the art would not have considered the teachings of Hu pertinent to the invention described in Tanno.”
Examiner disagrees. Hu is directed to using a pulsed laser, with power density greater than 107 W/cm2, to form hydrophilic graphite (abstract; p. 877, right column). This does relate to Tanno’s teachings of making a graphite surface hydrophilic (paragraphs 12, 22, & 44). The fact that Hu refers to the graphite balls as “onions” wouldn’t inhibit one skilled in the art from seeking guidance from Hu regarding laser power density for making their surfaces hydrophilic.
Applicant next argues:
“the Office Action combines certain laser parameters described in Tanno2 with laser parameters described in Tanno and determines that the proposed combination of Tanno and Tanno2 would have resulted in laser irradiation having a power density of more than 0.5MW/mm2… neither Tanno nor Tanno2 alone includes sufficient information to define the power density of laser irradiation used in their respective inventions. In that regard, Tanno only discloses a laser spot diameter and a laser pulse energy but is silent as to a laser pulse duration, such that the power density of the laser irradiation would not be known. Similarly, Tanno2 only discloses a power and a pulse duration but does not disclose a spot size, such that the power density of the laser irradiation would likewise be unknown.”
This is an obviousness rejection, so combination of references are expected. The fact that each individual reference doesn’t teach all claim limitations doesn’t preclude an obviousness rejection in which multiple reference combine to teach all claim limitations.
As discussed above, Tanno provides sufficient guidance for optimizing laser power density and achieving the claimed limitation. The added guidance from Tanno2 reduces the amount of experimentation required by one of skill in the art.
Both Tanno and Tanno2 teach laser irradiation on a fuel cell separator to increase hydrophilicity. One skilled in the art, seeking to optimize laser power density, would likely seek guidance from both Tanno and Tanno2. Tanno’s laser energy per unit area, combined with Tanno2’s pulse duration, would be a good starting place for experimentation by one skilled in the art. This combination results in values within the claimed laser power density range.
Applicant next argues against combining Tanno and Tanno2 because Tanno teaches two steps for increasing hydrophilicity (roughening then laser irradiation), but Tanno2 teaches only one step for increasing hydrophilicity (laser irradiation). This added teaching in Tanno would not inhibit one skilled in the art from learning details of laser irradiation from Tanno2, and applying this to the teachings of Tanno, for optimizing hydrophilicity.
Tanno’s teaching of roughening the surface introduces another variable into experimentation for optimizing hydrophilicity. This addition of one more variable would not greatly increase the amount of experimentation. “Design of Experiments” (DOE) often have multiple variables. A DOE is well-known, among engineers and scientists, for optimizing a product or process.
Applicant next argues that both Tanno and Tanno2 teach away from too high power density. The fact that Tanno and Tanno2 teach that the power density should not be so high that it results in damage the separator doesn’t mean that they teach away from the claimed range of ≥ 0.5 MW/mm2. The claim doesn’t require separator damage, which is what Tanno and Tanno2 teach away from.
Applicant next refers to WO2026070428A1, and its teaching to avoid too high laser power density for thin separators, in order to avoid damaging them. This does not overcome the combined teachings of Tanno and Tanno2 for the following reasons:
WO2026070428A1 is not prior art to the present application. It was filed more than four years after the effective filing date of the present application. It wouldn’t have been considered by one of skill in the art when the present application was filed.
Prior art not relied on by the examiner doesn’t prevent an obviousness rejection based on prior art that is relied on by the examiner.
WO2026070428A1 gives a caution for thin separators, but makes no statement that the claimed laser power density range should be avoided for all structures.
Applicant next argues the European Patent Office granted a patent for the European equivalent, based on the original claims. Examination of the present USA patent application is independent of the result of the European Patent Office. USPTO patent examiners often review and learn from office action responses in foreign countries, but are never required to comply with the conclusions in any foreign patent office.
Applicant next refers to the new claim 16 limitation:
“the pulsed laser irradiates the surface to be rendered hydrophilic with pulses having a pulse duration of less than 20 ns”
Examiner reviewed Applicant’s comments, and will respond in the 35 USC § 103 obviousness rejection below.
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
Determining the scope and contents of the prior art.
Ascertaining the differences between the prior art and the claims at issue.
Resolving the level of ordinary skill in the pertinent art.
Considering objective evidence present in the application indicating obviousness or nonobviousness.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
The claims are in bold font, the prior art is in parentheses.
Claims 16-18, 20-21, & 23-28 are rejected under 35 U.S.C. 103 as being unpatentable over US20150340713A1 (Tanno) in view of “Hydrophilic carbon onions synthesized by millisecond pulsed laser irradiation” (Hu), US20130171547A1 (Tanno2), and US20130020297A1 (Gupta).
Tanno teaches the following claim 16 limitations:
A method for forming a hydrophilic surface (paragraph 22) on a graphite-containing material (paragraph 22: graphite particles), wherein the surface to be rendered hydrophilic is irradiated with a pulsed laser (paragraphs 12, 22, & 44: pulsed infrared laser irradiation treatment)
Claim 16 also states that the laser has “a power density of at least 0.5 MW/mm2”. Tanno teaches that if the power density is too low, then hydrophilicity and electrical conductivity can decline (paragraph 45). It would have been obvious, to one of ordinary skill in the art, before the effective filing date of the invention, to achieve the claimed power density in order to avoid a decline in hydrophilicity and electrical conductivity, as taught by Tanno.
HU: Hu provides additional guidance. Hu teaches using a pulsed laser, with power density greater than 107 W/cm2, to form hydrophilic graphite (abstract; p. 877, right column). Hu teaches that the resulting hydrophilic product, which Hu calls “carbon onions", can be used for fuel cells. It would have been obvious, to one of ordinary skill in the art, before the effective filing date of the invention, for Tanno’s pulsed laser to have > 107 W/cm2 power density, as taught by Hu, to form a hydrophilic surface.
Following is an equation converting the pulsed laser units of Hu into the units of claim 1:
10
7
W
c
m
2
*
M
W
10
6
W
*
c
m
2
100
m
m
2
=
0.1
M
W
m
m
2
Hu’s > 0.1 MW/mm2 power density range overlaps the claimed ≥ 0.5 MW/mm2 range. MPEP 2144.05 (II)(A) provides the law for this issue:
“In the case where the claimed ranges ‘overlap or lie inside ranges disclosed by the prior art’ a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976)”
Given that Hu’s range is similar to and substantially overlaps the claimed range, and further given the fact that no criticality is disclosed for the claimed range, the range in claim 16 is an obvious variant of Hu’s range.
TANNO2: Tanno2 provides additional guidance. Tanno2 teaches laser irradiation on a fuel cell separator with graphite powder (paragraph 37) for high electrical conductivity, high hydrophilicity, and low leachability (paragraph 21). Tanno2’s laser pulse duration is 30 to 200 ns (paragraph 44). It would have been obvious, to one of ordinary skill in the art, before the effective filing date of the invention, for Tanno’s pulsed laser to have laser pulse duration of 30 to 200 ns, as taught by Tanno2, for high electrical conductivity, high hydrophilicity, and low leachability.
Combining Tanno2 with Tanno: Tanno teaches laser spot diameter = 300 μm (radius = 0.15 mm) and energy = 10 mJ (0.01 J) (paragraph 60). Tanno’s laser spot size = π*(0.15 mm)2 = 0.0707 mm2. Tanno’s energy per unit area: 0.01J/0.0707mm2 = 0.142 J/mm2. Here are equations combining Tanno’s energy per unit area with Tanno2’s pulse duration:
p
o
w
e
r
d
e
n
s
i
t
y
=
0.142
J
m
m
2
*
200
n
s
*
10
9
n
s
s
e
c
*
M
W
10
6
W
=
0.71
M
W
m
m
2
p
o
w
e
r
d
e
n
s
i
t
y
=
0.142
J
m
m
2
*
30
n
s
*
10
9
n
s
s
e
c
*
M
W
10
6
W
=
4.73
M
W
m
m
2
Combining Tanno’s laser energy & spot area with Tanno2’s pulse duration results in a 0.71 to 4.73 MW/mm2 range which is within the claimed ≥ 0.5 MW/mm2 range.
Claim 16 also states:
the pulsed laser irradiates the surface to be rendered hydrophilic with pulses having a pulse duration of less than 20 ns
The present specification provides the following guidance regarding laser pulse duration:
It is assumed to be advantageous if the pulsed laser irradiates the surface to be rendered hydrophilic with pulses having a pulse duration of less than 1 μs, preferably less than 100 ns or even less than 20 ns or less than 10 ns.
Based on this broad teaching of pulse duration ranges in the present specification, it seems that < 20 ns is not critical, and that similar results should be expected for < 1 μs and < 20 ns.
As discussed above, Tanno2’s laser pulse duration is 30 to 200 ns (paragraph 44), but claim 16 requires < 20 ns. MPEP 2144.05 (I) provides the law for this issue:
“Similarly, a prima facie case of obviousness exists where the claimed ranges or amounts do not overlap with the prior art but are merely close. Titanium Metals Corp. of America v. Banner, 778 F.2d 775, 783, 227 USPQ 773, 779 (Fed. Cir. 1985)… ‘The proportions are so close that prima facie one skilled in the art would have expected them to have the same properties.’”
Given that there is only a slight difference between Tanno2’s 30 to 200 ns and < 20 ns in claim 16, and further given the fact that no criticality is disclosed for the claimed range, the claimed range is an obvious variant of Tanno2’s range.
Gupta provides additional guidance. Gupta teaches > 0 ns to < 30 ns laser pulse duration (paragraph 31) to make a surface hydrophilic (paragraph 31). It would have been obvious, to one of ordinary skill in the art, to have applied Gupta’s range to the teachings of Tanno, and to try the 0-30 ns range, for making the surface hydrophilic.
Gupta’s 0-30 ns range overlaps the claimed < 20 ns range. MPEP 2144.05 (II)(A) provides the law for this issue:
“In the case where the claimed ranges ‘overlap or lie inside ranges disclosed by the prior art’ a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976)”
Given that Gupta’s range is similar to and substantially overlaps the claimed range, and further given the fact that no criticality is disclosed for the claimed range, the range in claim 16 is an obvious variant of Gupta’s range.
With regard to claims 17-18, modified Tanno teaches the limitations of claim 16 as described above. Tanno also teaches the following limitations of claims 17-18:
Claim 17
the pulsed laser irradiates the surface to be rendered hydrophilic with pulses having a pulse energy per unit area of at least 0.1 J/mm2 (Paragraph 60*****: 0.142 J/mm2. See calculation below.)
Claim 18
the pulsed laser irradiates the surface to be rendered hydrophilic with pulses having a pulse energy per unit area of less than 1 J/mm2 (Paragraph 60: 0.142 J/mm2. See calculation below.)
Tanno teaches laser spot diameter = 300 μm (radius = 0.15 mm) and energy = 10 mJ (0.01 J) (paragraph 60). Tanno’s area = π*(0.15 mm)2 = 0.0707 mm2. Tanno’s energy per unit area: 0.01J/0.0707mm2 = 0.142 J/mm2.
With regard to claims 20-21, modified Tanno teaches the limitations of claim 16 as described above. Tanno also teaches the following limitations of claims 20-21:
Claim 20
the pulsed laser irradiates the surface to be rendered hydrophilic with a pulse frequency of less than 100 kHz (paragraph 60: 30 kHz)
Claim 21
the pulsed laser irradiates the surface to be rendered hydrophilic with wavelengths of between 800 nm and 1500 nm (paragraph 60: 1.064 μm = 1064 nm)
With regard to claim 23, modified Tanno teaches the limitations of claim 16 as described above. Tanno also teaches the following limitation of claim 23:
the graphite-containing material has graphite particles which are embedded in a polymer matrix (paragraph 59: graphite powder mixed with epoxy resin)
With regard to claims 24-25, modified Tanno teaches the limitations of claim 16 as described above. Tanno also teaches the following limitations of claims 24-25:
Claim 24
the pulsed laser is additionally also used to remove from the graphite-containing material a superficial polymer layer and/or surface layer which consists of a material other than the graphite-containing material (paragraph 21: resin is removed during infrared laser irradiation)
Claim 25
the removal of the polymer layer and/or surface layer is carried out with same laser parameters as the formation of the hydrophilic surface (paragraph 21: no mention of different laser parameters for resin removal)
With regard to claims 26-27, modified Tanno teaches the limitations of claim 16 as described above. Tanno also teaches the following limitations of claims 26-27:
Claim 26
the graphite-containing material has a graphite content of at least 60 vol.% (Paragraph 59: 64.4%. See calculation below.)
Claim 27
the graphite-containing material has a polymer content of at least 20 vol.% (Paragraph 59: 23.8%. See calculation below.)
Tanno mixes the following components (assume 1 g / part) (paragraph 59):
100 parts by weight graphite powder (density1 = 2.26 g/cm3, so volume = 100/2.26 = 44.2 cm3.
18.3 parts by weight o-cresol novolak-type epoxy resin (density2 = 1.12 g/cm3, so volume = 18.3/1.12 = 16.3 cm3.
9.6 parts by weight of novolak-type phenolic resin (density3 = 1.32 g/cm3, so volume = 9.6/1.32 = 7.3 cm3.
0.19 part by weight of 2-phenylimidazole (density4 = 0.6 g/cm3, so volume = 0.19/0.6 = 0.32 cm3.
0.5 part by weight of carnauba wax (density5 = 0.999 g/cm3, so volume = 0.5/0.999 = 0.5 cm3.
Tanno’s vol% graphite:
T
a
n
n
o
’
s
v
o
l
%
g
r
a
p
h
i
t
e
=
44.2
44.2
+
16.3
+
7.3
+
0.32
+
0.5
*
100
%
=
64.4
%
Tanno’s vol% polymer (epoxy):
T
a
n
n
o
’
s
v
o
l
%
g
r
a
p
h
i
t
e
=
16.3
44.2
+
16.3
+
7.3
+
0.32
+
0.5
*
100
%
=
23.8
%
With regard to claim 28, modified Tanno teaches the limitations of claim 16 as described above. Modified Tanno also teaches the following limitations of claim 28:
A method for manufacturing a bipolar plate of a fuel cell (paragraph 59: fuel cell separator composition) or of a flow battery, wherein the method comprises:
providing a plate-like substrate which, at least adjacent to an exposed surface of the substrate, consists of a graphite-containing material (paragraph 59: graphite mix is placed in a mold and cured), and
forming at least part-regions of the exposed surface as a hydrophilic surface by means of the method according to claim 16 (see discussion under the claim 16 rejection above).
Claim 22 is rejected under 35 U.S.C. 103 as being unpatentable over US20150340713A1 (Tanno), “Hydrophilic carbon onions synthesized by millisecond pulsed laser irradiation” (Hu), US20130171547A1 (Tanno2), and US20130020297A1 (Gupta), as applied to claim 16, and further in view of US20100099000A1 (Kanba). Tanno fails to teach the following limitation of claim 22, which is taught by Kanba:
the surface to be rendered hydrophilic is exposed to a reactive gas atmosphere during the irradiation (paragraph 16: laser irradiation is carried out in a gas atmosphere containing oxygen)
Kanba forms hydrophilic functional groups on a fuel cell separator surface by laser irradiation. The separator includes graphite. Laser irradiation is performed in a gas atmosphere including oxygen. See paragraph 16. It would have been obvious, to one of ordinary skill in the art, before the effective filing date of the invention, for Tanno’s pulsed infrared laser irradiation treatment to be performed in a gas atmosphere including oxygen, as taught by Kanba, to help form hydrophilic functional groups on the fuel cell separator surface.
Claims 29-30 are rejected under 35 U.S.C. 103 as being unpatentable over US20150340713A1 (Tanno), “Hydrophilic carbon onions synthesized by millisecond pulsed laser irradiation” (Hu), US20130171547A1 (Tanno2), and US20130020297A1 (Gupta), as applied to claim 16, and further in view of US20080305385A1 (Smiljanich). Claims 29-30 require a bipolar plate for a fuel cell. Smiljanich teaches a bipolar plate for a electrochemical fuel cell stack (paragraph 28). It would have been obvious, to one of ordinary skill in the art, before the effective filing date of the invention, for Tanno’s fuel cell separator to be a bipolar plate for a electrochemical fuel cell stack, as taught by Smiljanich, to find a practical use for Tanno’s fuel cell separator.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any extension fee pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the date of this final action.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to ROBERT WEST whose telephone number is 703-756-1363 and email address is Robert.West@uspto.gov. The examiner can normally be reached Monday-Friday 10 am - 7 pm ET.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Allison Bourke can be reached at 303-297-4684.
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/R.G.W./Examiner, Art Unit 1721
/ALLISON BOURKE/Supervisory Patent Examiner, Art Unit 1721
1 https://powdermetallurgy.com/density-of-graphite/
2 https://www.chembk.com/en/chem/Ortho-Cresol%20Novolac%20Epoxy%20Resins
3 http://www.complast.com/POLYESTER/PHENOLIC_RESIN_DATA.htm
4 https://www.chemicalbook.com/ChemicalProductProperty_EN_CB8175874.htm
5 https://www.chemicalbook.com/ChemicalProductProperty_EN_CB1242157.htm
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