CORNING INCORPORATED

Patent Trials and Appeals Board

Jan 26, 2021

2020000493 (P.T.A.B. Jan. 26, 2021)

UNITED STATES PATENT AND TRADEMARK OFFICE
UNITED STATES DEPARTMENT OF COMMERCE
United States Patent and Trademark Office
Address: COMMISSIONER FOR PATENTS
P.O. Box 1450
Alexandria, Virginia 22313-1450
www.uspto.gov
APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO.
16/043,442 07/24/2018 Jaymin Amin SP15-384TA 3819
22928 7590 01/26/2021
CORNING INCORPORATED
SP-TI-3-1
CORNING, NY 14831
EXAMINER
KEYWORTH, PETER
ART UNIT PAPER NUMBER
1777
NOTIFICATION DATE DELIVERY MODE
01/26/2021 ELECTRONIC
Please find below and/or attached an Office communication concerning this application or proceeding.
The time period for reply, if any, is set in the attached communication.
Notice of the Office communication was sent electronically on above-indicated "Notification Date" to the
following e-mail address(es):
usdocket@corning.com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL AND APPEAL BOARD
Ex parte JAYMIN AMIN, XIAOJU GUO, TODD LEROY HECK,
HONGMEI HU, YUHUI JIN, PASCALE ORAM,
and LJERKA UKRAINCZYK
Appeal 2020-000493
Application 16/043,442
Technology Center 1700
Before BEVERLY A. FRANKLIN, JEFFREY B. ROBERTSON, and
SHELDON M. MCGEE, Administrative Patent Judges.
MCGEE, Administrative Patent Judge.
DECISION ON APPEAL
Pursuant to 35 U.S.C. § 134(a), Appellant1 appeals from the
Examiner’s decision to reject claims 1–5, 7, 9–15, and 17–31. We have
jurisdiction. 35 U.S.C. § 6(b).
We affirm-in-part.

1 We use the word Appellant to refer to “applicant” as defined in 37 C.F.R.
§ 1.42. Appellant identifies the real party in interest as Corning
Incorporated. Appeal Br. 2.
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Application 16/043,442

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CLAIMED SUBJECT MATTER
The claims are directed to methods of regenerating a salt bath
containing lithium (Li) ions. Claim 1, reproduced below, is illustrative of the
claimed subject matter, with a key limitation italicized for emphasis:
1. A method for regenerating a salt bath comprising:
heating a salt bath comprising a phosphate salt and at least
one of KNO3 and NaNO3 to a temperature of greater than or
equal to 380°C;
contacting at least a portion of an ion-exchangeable substrate
comprising lithium cations with the salt bath, whereby lithium
cations diffuse from the ion-exchangeable substrate and are
dissolved in the salt bath; and
selectively precipitating, before or between ion-exchange
cycles, dissolved lithium cations from the salt bath, wherein
the concentration of dissolved lithium in the salt bath is
greater than or equal to 0 wt% lithium and less than or equal
to 2.0 wt% lithium, and wherein the concentration of lithium
cations in the salt bath is greater than or equal to the
concentration of phosphate salt in the bath.
Figures 1A, 1B, 2A, and 2B are illustrative of the claimed method.

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Figure 1A depicts a salt bath 100 containing fresh molten salt 101, ion-
exchangeable substrate 105 containing Li ions 130, and alkali metal ions
120. Spec. ¶ 53. Figure 1B depicts a “poisoned” salt bath 100 after an ion-
exchange reaction where some of the Li ions 130 in substrate 105 and
diffuse and are replaced with “larger alkali metal cations.” Id. ¶¶ 55–56.

Figure 2A depicts poisoned salt bath 200 with the ion-exchangeable
substrate removed, where poisoned molten salt 202 contains more than 2 %
by weight of Li ions, and where “phosphate salt 240 may be added before or
after the ion-exchangeable substrate 205 is contacted with the salt bath” to
precipitate out the Li ions, thus “regenerat[ing] the poisoned molten salt.”
Id. ¶ 57. Figure 2B illustrates regenerated salt bath 200 where the phosphate
salt precipitates Li ions out of the salt bath thereby creating insoluble lithium
phosphate 250. Id. ¶ 60.
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REJECTIONS
The Examiner rejects the following claims under 35 U.S.C. § 103:
I. Claims 1–5, 7, 9–15, and 17–20 as unpatentable over Imai;2
II. Claims 21–31 as unpatentable over Imai in view of Gomez.3
Final Act. 2–8.
OPINION
Rejection I
We address the claims separately to the extent so argued by Appellant.
37 C.F.R. § 41.37(c)(1)(iv)(2019).
Claim 1
The Examiner’s findings regarding Imai and conclusions regarding
the obviousness of claim 1 are set forth at pages 2–4 of the Final Office
Action.
Appellant first argues the prior art Imai reference teaches that its
precipitation reaction is carried out “during” the ion exchange reaction and,
thus, does not “selectively precipitat[e] before or between ion-exchange
cycles” as required by claim 1. Appeal Br. 10–13; Reply Br. 4–5. We are
not persuaded by this argument for several reasons.
First, the method of claim 1 does not require the selective
precipitation of dissolved lithium cations to occur solely before or between
ion-exchange cycles. Indeed, claim 1 is open-ended and, as such, may
include non-recited steps such as simultaneous precipitation and ion-
exchange reactions. Thus, the Examiner’s reliance on a reference that may

2 US 8,919,150 B2, issued December 30, 2014.
3 US 2012/0052271 A1, published March 1, 2012.
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also disclose a precipitation reaction occurring during ion exchange does
not, by itself, constitute reversible error.
Further, Appellant’s focus on Imai’s simultaneous precipitation and
ion exchange reactions does not address whether Imai also teaches or
suggests selective precipitation of lithium ions “before or between ion
exchange cycles.” In this regard, Appellant does not squarely address the
totality of the Examiner’s findings that this limitation is met by Imai’s
process. Specifically, the Examiner finds that Imai discloses regeneration
and reuse of the molten salt bath by adding an additive to precipitate ions,
thus “such precipitation reaction would occur before or between ion
exchange cycles.” Final Act. 2–3; see also Ans. 3–4 (finding that Imai
teaches alternating ion-exchange and precipitation cycles, where an ion-
exchange reaction occurs, followed by a precipitation cycle, which then
repeats). Because Imai’s precipitation cycle occurs after one ion exchange
cycle and before another, the Examiner finds that “the precipitation occurs
between the ion exchange cycles” as recited in claim 1. Ans. 3–4.
Moreover, the Examiner finds that “Imai teaches that the additive may
be added per batch or per several batches while producing a plurality of ion
exchanged glass articles.” Ans. 4 (citing Imai 7:51–63). Thus, according to
the Examiner, the disputed limitation is met because “the precipitation
reaction is an inherent effect of Li ions being in the presence of and reacting
with a phosphate salt.” Id. In other words, the Examiner finds that selective
precipitation of lithium ions occurs “between ion exchange cycles” in Imai
because the ion exchange reaction occurs when the substrate is present
within the salt bath; once the substrate is removed, ion exchange ceases, but
precipitation continues based on the amount of phosphate present in the salt
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bath. See Ans. 4 (finding “as long as the phosphate salt and Li ions are
present, the selective precipitating would occur and would overlap the
timeframe between batches, even if not explicitly stated.”).
Here, we acknowledge Appellant’s argument that, in the claimed
method, precipitation would not continue after removing the substrate
because the claimed amount of phosphate does not exceed the concentration
of lithium ions in solution. See Reply Br. 5 (arguing that in the claimed
method, “because the amount of lithium cations is greater than[4] the amount
of phosphate salt, all the phosphate salt will be precipitated before or
between ion-exchange cycles; there will be no phosphate salt after the
precipitating”); see also id. (arguing that, in Imai, “because there is so much
phosphate salt, there will not be any unprecipitated lithium cations when the
ion exchange cycle is done” thus, “between the end of the first ion exchange
cycle and the start of the second ion exchange cycle . . . there will be no
precipitation”). This line of argument is unpersuasive, however, because it
is an assertion unsupported by evidence. See In re Pearson, 494 F.2d 1399,
1405 (CCPA 1974) (“Attorney’s argument in a brief cannot take the place of
evidence.”). In particular, Appellant has not shown that there are no
unprecipitated lithium cations present in Imai’s salt bath between ion
exchange cycles.
Appellant also argues that it would not have been obvious to change
Imai’s method step sequence to arrive at the claim limitation requiring the
precipitation to occur “before or between ion exchange cycles” as claimed.
Appeal Br. 13–14. We need not address this argument, however, because it

4 This argument misstates the claim, which allows the concentration of
lithium to equal that of the phosphate salt in the bath.
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addresses an alternative rationale relied on by the Examiner regarding this
limitation. See Final Act. 3. As discussed supra, we find no error in the
Examiner’s finding that Imai teaches selective precipitation occurring
“between ion exchange cycles.” Final Act. 2–3; Ans. 3–4.
Appellant contends further that the Examiner’s optimization rationale
to arrive at the claimed percentages of lithium and phosphate is not
supported because the prior art does not recognize the concentration of
lithium ions and phosphate salt to be result effective variables. Appeal Br.
14–16. This argument is not persuasive of reversible error because the
Examiner finds, and Appellant does not dispute, that the skilled artisan
“would immediately recognize that in the case of chemical reactions, the
concentration of reactants play a critical role in controlling/optimizing the
chemical reaction.” Ans. 5; see Reply Br., generally. Moreover, Imai
evinces the result effective nature of lithium ions. Imai 4:56–62 (discussing
how the concentration of lithium ions impacts the degree to which sodium
and potassium ions can enter the glass substrate upon equilibrium); see also
id. at 5:3–5 (“the glass strengthening degree changes along with the change
in concentration of Li ions in the molten salt dissolved solution”).
Finally, Appellant argues that the Examiner’s reliance on certain
percentages previously claimed in now canceled claim 8 is in error. This
argument is not persuasive because such reliance on claim 8 was an
alternative to the process optimization line of reasoning supporting the
rejection (Final Act. 4) for which Appellant has identified no error.
In sum, Appellant’s arguments regarding claim 1 fail to identify
reversible error in the rejection of this claim. We, therefore, sustain it, along
with dependent claims 2–5, 7, 9, 10, and 17 not argued separately.
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Claim 11
Claim 11 requires additional steps not recited in claim 1, namely a
measuring of the compressive stress of a first substrate after contact with the
salt bath, additional measuring of the compressive stresses of subsequent
substrates after contact with the salt bath, and adding phosphate salt to the
salt bath “when a compressive stress of a subsequent ion-exchangeable
substrate is from 10 MPa to 70 MPa less than the compressive stress of the
first ion-exchangeable substrate.”
The Examiner finds that Imai fails to teach these additional steps, but
determines these steps would have been obvious in view of Imai’s teaching
that “the process of chemical strengthening allows for the glass substrate to
increase its compressive stress,” and because “modifying the order of the
process would have been an obvious matter of changing the sequence in the
method.” Final Act. 5.
Appellant argues that even if the substrates’ compressive stresses
were measured to see if it was a desired amount, “there is no cogent line of
reasoning as to why that would be used as a factor in determining when to
add phosphate salt to the ion-exchange bath to remove lithium ions
therefrom.” Appeal Br. 17–18. Rather, according to Appellant, Imai
teaches maintaining enough phosphate in the bath so that lithium ions may
be discharged during ion exchange “so that the salt bath does not need to be
replaced.” Id. at 18.
We reverse the rejection of claim 11. The Examiner fails to explain
sufficiently why the skilled artisan would have been motivated to modify
Imai’s process by adding phosphate to the bath once a difference between
compressive stress measurements of between 10 and 70 MPa in the substrate
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is observed. Specifically, the rejection appears to conflate the desire to
removal of lithium ions from a substrate (e.g., to obtain a given compressive
stress (Imai 4:39–46)) with removal of lithium ions from the salt bath by
adding phosphate. Furthermore, the Examiner fails to explain how the
proffered “order of steps” rationale applies to the facts here.
Because the rejection of claim 11 is deficient, we reverse it, along
with the rejection of dependent claims 12–15 and 18–20.
Rejection II
Because we have reversed the rejection of independent claim 11
supra, the rejection of claims 21–25 depending therefrom also will be
reversed.
Thus, we need only address claims 26–31 because these claims
depend from claim 1. Appellant argues this rejection as a group, except for
claim 30 which is argued separately. Appeal Br. 18–19. We, therefore,
select claims 26 and 30 and decide the appeal of this rejection based on these
claims. 37 C.F.R. § 41.37(c)(1)(iv)(2019).
Claim 26
For claim 26, Appellant relies on the same arguments presented for
claim 1, discussed supra. Because we found those arguments unpersuasive
for claim 1, we do so here, and sustain the rejection of claim 26 and claims
27–29 for the same reasons.
Claim 30
Claim 30 requires “cooling the ion-exchangeable substrate to a
temperature of less than or equal to 100°C in less than or equal to 3 minutes”
after it is removed from the salt bath.
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The Examiner finds that Imai teaches the substrate is rapidly cooled
after being removed from the salt bath and that the skilled artisan would
have expected the recited temperature to be achieved in less than or equal to
3 minutes. The Examiner alternatively determines that the claimed cooling
rate would have been an obvious matter of routine optimization. Final Act.
7; see also Ans. 6 (“The end temperature of the substrate and the time taken
to cool to said temperature are the effects of the method step of the substrate
being immersed in a water bath. Relevant factors that would affect the
degree and rate of the cooling process would be the temperature of the water
bath.”).
Appellant argues that the Examiner’s optimization rationale is
misplaced because the prior art does not recognize the cooling rate as a
result effective variable, “let alone as result-effective of controlling
formation of phosphate crystals as Appellant has.” Appeal Br. 18–19. We
are unpersuaded by this argument.
First, we note that Appellant only presents arguments regarding the
Examiner’s optimization rationale, and does not address the Examiner’s
finding that the skilled artisan would have expected Imai’s cooling process
to achieve the claimed cooling rate. Final Act. 7.
Further, Appellant’s arguments do not address the Examiner’s finding
that the temperature of the water bath is a result effective variable that would
affect the substrate’s cooling rate, and is, therefore, optimizable. Ans. 6;
Reply Br., generally. Rather, Appellant appears to argue that a given
parameter must be known to be result-effective for the feature with which
Appellant is concerned. Appeal Br. 18. This is not the law. In re Applied
Materials, Inc., 692 F.3d 1289, 1297 (Fed. Cir. 2012) (“the prior art need not
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provide the exact method of optimization for the variable to be result-
effective. A recognition in the prior art that a property is affected by the
variable is sufficient to find the variable result-effective.”).
Because we are unpersuaded of reversible error in the rejection of
claim 30, we sustain it, along with the rejection of claim 31 depending
therefrom.
CONCLUSION
The Examiner’s rejection of claims 1–5, 7, 9, 10, 17, and 26–31 is
affirmed.
The Examiner’s rejection of claims 11–15 and 18–25 is reversed.
DECISION SUMMARY
Claims
Rejected
35 U.S.C. § Basis Affirmed Reversed
1–5, 7, 9–15,
17–20
103 Imai 1–5, 7, 9,
10, 17
11–15, 18–
20
21–31 103 Imai, Gomez 26–31 21–25
Overall
outcome
1–5, 7, 9,
10, 17, 26–
31
11–15, 18–
25
TIME PERIOD FOR RESPONSE
No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C.F.R. § 1.136(a). See 37 C.F.R.
§ 1.136(a)(1)(iv).
AFFIRMED-IN-PART